INSTRUCTION MANUAL
Laboratory Equipment Pty Ltd
email: sales@labec.com.au
Ph: 02 9560 2 811 • Fax: 02 9560 61 3 1
www.labec.com.au
2014
Operation Manual for
Milk Analyzer
MIA-LA
PLEASE READ THIS MANUAL CAREFULLY BEFORE OPERATION
Ultrasonic milkanalyser
Switching Adapter
• Input: 100 - 240 V ~1.6 A max.
50-60 Hz
• Output: +12 V
4.17А min.
• Output power: 50 - 65 W
Measurement modes
• cow milk
• sheep milk
• UHT milk
• goat milk
• buffalo milk
• cream
• whey
• recovered milk
• other /pasteurized milk/
CAUTION!
Keep the switching adapter dry!
Please, read and follow strictly all the instructions in the manual.
Due to continuous improvement in milk analyser, information contained in this
manual is subject to change without notice. Contact producer for revisions
and corrections
Ultrasonic milkanalyser
SAFETY INSTRUCTIONS
1. Read this manual carefully and make sure that you understand all the
instructions.
2. For safety purposes the device is equipped with grounded power
cable. If there is no grounded electrical outlet where the device will
be used, please, install such before using the device.
3. Place the device on leveled and stable plate. In case it falls or is
severely shocked it may be damaged.
4. Connect to the electrical network in such a way that the power cable
to stay away from the side for accessing the device and not to be
stepped on.
5. Every time before cleaning the device switch it off and unplug it from
the electrical outlet. The device has to remain unplugged till the
cleaning completion.
6. Do not disassemble the unit in order to avoid possible electrical
shock. In case of malfunction contact your local dealer.
7. Handle the liquids the device works with carefully, following all the
instructions for their preparation.
8. Place the switching adaptor in such a way as to be protected from
overflow and spillage of liquids.
Ultrasonic milkanalyser
PARTS AND ACCESSORIES
In the table below the standard delivery configuration of the milk analyser is
listed:
№ Description
Item № pcs
1. Ultrasonic portable milk analyzer LSLA001 1
1 sample measurement time
90 sec.
60 sec
30 sec
2. Operation manual LSLA002 1
3. Plastic sample holder LSLA003 2
4. Spare Pipes LSLA004 2
5. 12 V DC Power Supply Cable LSLA005 1
6. Alkaline cleaning solution Lactodaily 100 g 1
7. Acidic cleaning solution Lactoweekly 100 g 1
In the table below the milk analyser spares and accessories, which are
delivered on customers’ request are listed:
№ Description
a) included in the set:
Item № pcs
/
b) not included in the set (may be
additionally bought):
8. RS232 Interface Cable - Analyser-IBM PC LSLA006
9. Service Pack - CD LSLA007
10. pH measuring system LSLAS009 1
11. pH probe with cable and holder LSLA010 1
12. Buffer solution Ph 60 ml
LSLA011 1
(pH7.00±0.01/20˚C)
13. Buffer solution pH 60 ml
LSLA012 1
(pH4.00±0.01/20˚C)
14. Milk conductivity measuring system LSLA013 1
15. Buffer solution conductivity 50 ml (5.02
LSLA014 1
(±5%) mS/cm (18±0.1˚C)
16. Real time clock LSLA015 1
17. High-fat measuring function LSLA016 1
Ultrasonic milkanalyser
18. ECS POS Serial Printer LSLA017 1
19. 12 V Serial Printer Power Supply Cable LSLA018 1
20. RS232 Interface Cable - Milk Analyser –
Serial Printer
21. Power supply from embedded accumulator
with charger
LSLA019 1
LSLA021 1
1
22. Plug type
1
Ultrasonic milkanalyser
1. FUNCTION
The function of the milk analyser is to make quick analyses of milk on
fat (FAT), non-fat solids (SNF), proteins, lactose and water content
o
percentages, temperature (
С), pH, freezing point, salts, conductivity as
well as density of one and the same sample directly after milking, at
collecting and during processing.
Ultrasonic milkanalyser
2. TECHNICAL PARAMETERS
2.1. Working modes characteristics:
The program of the milk analyser has four working modes.
2.1.1. Measurement mode milk / dairy product – first type
2.1.2. Measurement mode milk / dairy product – second type
2.1.3. Measurement mode milk / dairy product – third type
These modes have been calibrated on customers’ request for 3 milk types
from the following: cow, sheep, UHT, buffalo, goat, camel milk, cream, ice
cream mixtures, whey, recovered milk, etc. before leaving the production
facilities and the text on the display will be for the corresponding types, as is
indicated on page 2 Measurement modes.
2.1.4. Cleaning
2.1.4.1. Current
2.1.4.2. Final
Ultrasonic milkanalyser
2.2. Measuring range:
Fat ………………..................... …………..from 0.01% to 25% (45%*)
SNF ……………………………… ...…………………....from 3% to 40%
Density ** ………………………. ……...…….from 1000 to 1160 kg/m3
Proteins …………………………. ……………………..from 2% to 15%
Lactose ………………………... …………………from 0.01 % to 20 %
Water content ………………… ……………...……..from 0 % to 70 %
Temperature of milk …………… from 5oC to 40oC (if measurement is
30 sec, then t° is from 15 to 40°)
Freezing point ****……………… …………..from – 0,400 to – 0,700oC
Salts ……………………………. …...…………...………from 0,4 to 4%
PH***……………………………... …………………..………from 0 to 14
Conductivity** ………………… ……………...…from 2 to 14 [mS/cm]
* Option, on customers’ request
** Density data are shown in an abbreviated form. For example 27.3 have to
3
be understood as 1027.3 kg/m
. To determine the milk density, write down
the result from the display and add 1000.
Example: result 21,20; density = 1000 + 31,20 = 1031,2 kg/m
3
The abbreviated form of the density is used also when entering data for
samples in working mode Recalibrate, for example:
If the measured sample density is 1034.5 kg/m3, then in the menu for
entering the samples parameters used for calibration, across the parameter
Den = , you have to enter 34.5.
*** pH and conductivity measurements are optional and are embedded in the
device on customers' request.
**** Please, carefully read Appendix Freezing Point.
Ultrasonic milkanalyser
2.3. Accuracy:
Fat …..………………………………..
SNF …………………………………..
Density ………………………………
Proteins ……………………………...
Lactose ………………………………
Water content ……………………….
Temperature of milk ………………..
Freezing point………………………..
Salts ………………………………...
…...………………….…...± 0.06%
…………...………….…...± 0.15%
………………………..± 0.3 kg/m
……...……………….…...± 0.15%
.…………………………...± 0.20%
.…………………………….± 3.0%
.………………………………± 1
..……...…………………± 0.005
…..…………...…………...± 0.05%
PH** …………………………………. ………………………………±0.05
Conductivity** ………………………. ……………………..±0.05[mS/cm]
o
o
3
C
C
Accuracy values in point 2.3 are in dependence on the correctness of the
corresponding chemical method, used for component content determination.
In point 2.3. are used the following reference methods: Gerber – for fat,
gravimetric – for SNF, Kjeldahl – for protein. The boundary for maximum
variation of repeatability when the power supply voltage is from +10 to – 15%
from the nominal voltage values (220V) have to be no more than 0.8
accuracy according point 2.3. The analyser is used in conditions free of outer
electrical and magnetic fields (except the magnetic field of the Earth) and
vibrations.
2.4 Correct ambient conditions:
Accuracy is guaranteed in case of normal ambient conditions:
Air temperature………………………… ….…from 10
o
C to 40oC (43 oC)
Relative humidity ……………………… ……………...from 30% to 80%
Power supply ………………………… …………………...220V (110V)
extent of contamination at normal environmental conditions…………..2
2.5. Dimensions:………………………….250/290/300 mm, mass 4,0 kg
2.6. Continuous working time:
………….………………………….…...……....non-stop
2.7 Milk sample volume per one measurement:
3
………………………………..………..15 cm
(= 15 ml)
Ultrasonic milkanalyser
Fig.1 Front panel
1. Button Up 6.pH probe holder
2. Display 7.input pipe
3. Button Enter 8. sample holder
4. Button Down 9.waste liquid pipe
5.pH probe 10. ss grid
Ultrasonic milkanalyser
Fig.2 Back panel
1. Power switch 8. Com Port 2
2. AC adaptor input 9. Com Port 1
3. DC Power Supply output 10. Connector for the cleaning solution
4. Parallel printer connector 11. Plastic pipe
5. pH probe input (option) 12. Metal pipe
6. Weigh Scale input (option) 13. Switching adapter
7. pH probe
Ultrasonic milkanalyser
Fig 3 Principle working scheme
Ultrasonic milkanalyser
Fig. 4 Connecting peripheral devices
Ultrasonic milkanalyser
Fig. 5 Cable Description
Art. Number 30011
RS232 Interface Cable - Milk Analyser – Serial Printer
Art. Number 30012
RS232 Interface Cable - Milk Analyser – IBM PC
2. TxD
3. RxD
5. GND
Milk
Analyser
DB 9-pin
male
PC
DB 9-pin
female
2. Receive Data
(RxD)
3. Transmit Data
(TxD)
5. Signal Ground
(GND)
Art. Number 10128
Probe pH with cable
Art. Number 30030
DC 12V Power Supply Milk Analyser Cable
1. GND
2. No connection
3. No connection
4. 12V DC
Ultrasonic milkanalyser
3. QUALIFICATION OF RAW MILK, THERMALLY TREATED
MILK, OTHER DAIRY PRODUCTS AND DERIVATIVES
3.1. Taking samples and preparation for analyses
In order to receive reliable results in qualification of milk, dairy products and
derivatives are needed: precise samples taking; correct samples storing (in
need to be preserved); correct preparation before making measurement. The
rules and requirements for this are described in details in Appendix Milk
sampling.
3.2. Making the measurement.
3.2.1. Preparing the analyser for working mode
3.2.1.1. Put the analyser on the working place, providing good ventilation and
not in the vicinity of heat providing devices or sources. The temperature in the
premises has to be in the boundaries 10-40
3.2.1.2. Check if the power switch is in "0" position and that the outlet voltage
complies with the voltage indicated on the switching adapter of the analyser
3.2.1.3. Switch on the “POWER” button, which starts the identification
procedure. For a short time the display shows the number of the software
versions, for example:
Milk analyser xxx
LCD vers xx
MA vers yy
MA ser. N. xxxx
Where:
Milk analyser xxx - is the time for measurement.
LCD vers XX - is display control software version.
MA vers YY - is the motherboard software version.
MA ser. N. xxxx - is the serial number .
o
C.
Ultrasonic milkanalyser
If in the process of exploitation there is a need to ask a question the
company-producer, you have to send the data, written on the display during
the above described initialization procedure.
3.2.1.4.Till the analyser is prepared for work (at about 5 minutes) the
following message is written on the display: “Getting ready”. Above pointed
time is in dependence of the environmental temperature and increases with
decreasing the temperature.
3.2.1.5. When the device is ready for work, a beep is heard and the display
shows: “Ready to start”. The analyser is ready to make analyses in mode 1
(normally Cow)
3.2.1.6. If you want to pass to another mode press the button Enter and hold
it pressed. The following message appears on the display:
Release button to
start menu
Release the button Enter. The display shows the possible working modes:
Milk selector
Cal1 – Cow
Cal2 – Sheep
Cal3 – UHT
-----------------------------Cleaning
Final clean
Using “up”▲and”down”▼buttons choose the working mode and press Enter
in order to start it.
3.2.2. Making analyses
Ultrasonic milkanalyser
Make sure the analyser is still during measurement. Vibrations may lead to
inaccurate results.
To start measurement:
- pour the preliminary prepared sample in the sample holder (now you may
use holders with different size - plastic and glass 100 ml);
Fig.6 Input pipe
The input pipe of the analyser is knee-joint (mobile). Move it forward in order
to be possible to dip its end in the milk sample and place the sample holder in
the recess of the analyser..
- press the button Enter.
The analyser sucks the milk, makes the measurement and used milk sample
is poured through the holes of the grid below the input pipe of the analyser
and enters the vessel for collecting waste liquids (see Fig. 3 Principle working
scheme of the analyser). During the measurement the temperature of the
sample is shown on the display.
Ignore the results received immediately after switching on the analyser and
after measuring distilled water. Make a second measurement with new
portion of the same sample.
3.2.3. Displaying the results
3.2.3.1. When the measurement is finished, the sample returns in the
sample-holder and the display shows the results. For example:
Results:
F=ff.ff S=ss.ss
D=dd.dd P=pp.pp
L=ll.ll W=ww.ww
Where:
Ultrasonic milkanalyser
F= ff.ff - measured FAT in percentage;
S= ss.ss - measured SNF in percentage;
D= dd.dd - measured density in percentage;
P= pp.pp - measured protein in percentage;
L= ll.ll - measured lactose in percentage;
W= ww.ww - measured sample’s added water in percentage;
By pressing the button” Down” ▼ the display shows the second page,
containing the results:
Page 2 Results:
T=tt.tC pH=pp.pp
FP=-0.fff sol=0.sss
Where:
tt.tC - sample’s temperature;
pp.pp - sample’s pH result – if there is a pH probe connected;
-0.fff - measured sample’s freezing point;
0.sss - measured salts values;
By pressing the button”Up” ▲ display shows the third page with results:
Page 3 Results:
L=l.ll
Where:
L= ll.ll - measured Lactose in %;
By pressing the buttons “up”▲ and”down”▼, the operator has the possibility
to pass from one page result to another.
If the device has an embedded option “Conductivity” and "conductivity
measurement" started, the result is shown on the display, showing the basic
results replacing lactose results in the following way:
C=xx.xx
In this case the Lactose result is shown on a new page - Page 3 Results.
xx.xx is the measured milk sample’s conductivity in [mS/cm]. If the results are
outside the limits for this type of sample (see table from the Appendix
Ultrasonic milkanalyser
Conductivity measurement), the cursor flashes after the letter С, reminding
that the sample is not correct. On the printout it is printed as !!!.
If the conductiity value is outside measuring range (2-14 mS/cm), the
following message appears on the display:
C=OutRg (Out of Range), and on the printout there isn’t any line with
conductivity value.
3.2.3.2. Write down the results in the form. The results remain on the display
till a new measurement is started. If the analyser is connected to a computer,
it automatically sends the data to the computer and/or prints them.
Ultrasonic milkanalyser
4. CLEANING THE ANALYSER
This procedure prevents gathering milk fat residues and milk stone on the
sensor. The milk stone consists of milk solids, calcium, iron, sulphates,
magnesium, etc. All these substances form layer on the pipe and sensor’s
walls, which leads to deviations in the measurement results and blocking up
the piping.
The company-producer recommends usage of the chemicals, supplied with
the analyser – alkaline and acidic (Lactodaily and Lactoweekly). You may
order them separately or together with the analyser. Try to use only these
chemicals for cleaning the analyser.
In case you missed to order these chemicals the alternative is to use alkaline
and acidic cleaning solutions for dairy, produced by one the companies,
supplying such chemicals:
http://www.johnsondiversey.com/Cultures/en-GB/OpCo/Your+Business/Dairies.htm
http://www.ecolab.com/SolutionGuide3.asp?name=1345&PS_GRP_CD=FDBV&BUS_NM
http://www.calvatis.com/documents/products/produkte_farm_melkhygiene.pdf
4.1. Automatic cleaning the analyser
Analyser's contamination as a result of the irregular cleaning is the basic
reason for inexactness during measurement. In order to be avoid this, in the
milk analysers with peristaltic pump is embedded automatic cleaning. For this
purpose the analyser has to be prepared on the following way:
The reservoir with the cleaning solution have to be connected towards the
analyser and outgoing pipe towards reservoir for collecting the measured
samples and used cleaning solution, as is shown on Fig.2.
Pay attention to the pipes in both reservoirs. The pipe in the reservoir with the
cleaning solution has to be well dipped in the cleaning solution while the pipe
in the reservoir with the already used samples and cleaning solution MUST
NOT be dipped in the liquid.
Pay attention to the level of the cleaning solution in the reservoir. Add
solution when the level is below 2/3!
Description of the cleaning procedures:
Ultrasonic milkanalyser
There are two ways of cleaning the analyser embedded in it – current and
end (final) cleaning.
4.1.1. Current cleaning.
4.1.1.1. Automatic start
The current cleaning is made with alkaline solution (for working solution
preparation see 4.2.1.), with which the reservoir for the cleaning solution is
filled in.
It is automatically started, without operator's interference after the set time
intevals elapse
1. 55 min. after switching on the power supply of the analyser,
but idle work;
2. 15 min. after the last measurement of real milk sample.
After cleaning a new measurement is started in the above described
intervals.
The display shows the following message and a sound signal is emitted:
Auto clean
started!
Put empty glass
After this the cleaning is started. The display shows:
Cleaning
Please wait
If there is a glass with sample it is completely emptied and then the analyser
automatically fulfills procedure for sucking the cleaning solution and c rinsing
the analyser's inner system. In order the input metal pipe to be cleaned out
for a short time a cleaning solution is pumped out for a short time in the
already empty glass or in case there is no empty glass there – in the funnel
for the waste liquids. It is filled to the middle and then is sucked back and
poured in the reservoir with the used liquids. In case that you are sure that
you’ll not use the analyser for a longer period, but it will be connected to the
power supply and switched on, which means that the process of automatic
clean will be active, do not leave sample holder in the recess of the analyser,
in order not to be overfilled during cleaning from the output pipe. Then the
cleaning solution will be directly poured in the funnel for waste liquids.
Ultrasonic milkanalyser
After the cleaning is finished the displays shows the following:
End of cleaning
After 2 seconds the display shows:
Analyser ready
Then the analyser is ready for normal measurement.
4.1.1.2. Manual start
The current cleaning may be completed by manual start of the menu
Cleaning. It is used before starting the menu Final Clean. It serves for
cleaning the fats from the measuring tract with alkaline cleaning solution with
which the canister is filled in. It is started using the menu for choosing the
working mode of the analyser. After the measurement is completes, by
continuous pressing the button Enter, the possible analyser operation modes
are shown on the display.
Cow
Sheep
UHT
Cleaning
Final Clean
By choosing Cleaning the current cleaning is started. The display shows the
following:
Auto clean
started!
Put empty glass
In this way the current cleaning is started. The procedure and operator’s
actions are described above.
Ultrasonic milkanalyser
Do not switch off the device at the end of the working day before the
automatic cleaning procedure is completed. If it is not automatically cleaned
and there is not a possibility to wait starting the automatic cleaning, then start
manually the cleaning procedure with alkaline cleaning solution and if it is
necessary with acidic cleaning solution as it is described below.
4.1.2. End (final) cleaning.
4.1.2.1. Final cleaning.
It is done with acidic cleaning detergent (for working solution preparation see
4.2.2.). It is done daily. Serves for cleaning the protein deposits from the
measuring system of the analyser, which were not removed during work with
the alkaline cleaning solution and removing milk stone layers.
Do not use chemicals, which are not intended for milking equipment and
vessels in dairy industry. Pay particular attention to the acidic cleaning
solution concentration. The higher concentration may damage the measuring
sensor.
Always before the final acidic cleaning rinse the device with alkaline cleaning
solution by manual starting if it was not already automatically cleaned. It is
necessary to be done in order to remove the milk residues which could react
with the acidic cleaning solution.
Do not forget to rinse with clean water!
It is started using the working modes menu. After the measurement is
completed, by pressing and holding pressed the button Enter, the display
shows the possible working modes of the analyser.
Cow
Sheep
UHT
Cleaning
Final Clean
Ultrasonic milkanalyser
1. Choose Final Clean. After choosing the final cleaning, the following
message appears on the display:
Put filled with
Water glass
and press Enter
to Continue
2. Put a glass filled with water and press the button Enter in order to continue
the procedure. Then the following message appears on the display:
Cleaning
Please wait
Do not miss to clean with water because the residues from the alkaline
cleaning solution could react with the acidic solution, which will lead to gas
and sediment formation.
After rinsing with water, the display shows the following:
Put filled with
Detergent glass
and press Enter
to Continue
3. Pour warm alkaline solution in the glass and press the button Enter, in
order to continue the cleaning.
Then the following message appears on the display:
Cleaning
Please wait
Ultrasonic milkanalyser
Follow repeatedly sucking/pouring out the cleaning solution and heating it up.
After the cleaning is finished, the cleaning solution is emitted in the reservoir
with the waste liquids.
For maximum cleaning effect it is recommended the cleaning solution to be
preliminary heated up to 40-50 degrees centigrade.
Follows rinsing with water:
4. Put a glass with water for rinsing the device.
Put filled with
Water glass
and press Enter
to Continue
After rinsing the display shows the following:
End of cleaning
After 2 seconds the following appears on the display:
Analyser ready
After this the analyser is ready for normal measurement or to be switched off
from the power supply.
Ultrasonic milkanalyser
4.2. Preparation of cleaning solution
4.2.1. Preparation of alkaline cleaning solution
Preparation of 1 % alkaline solution of Lactodaily for circulation cleaning in
the milk analyser:
1. Take the package 100 g concentrated powder chemical Lactodaily
2. Carefully cut the upper end, paying attention not to spill it.
3. In appropriate vessel (for example bucket) pour 1 l water.
4. Add the powder and then again water up to 10 l.
Then follow the instruction for milk analyser cleaning.
4.2.2. Preparation of acidic cleaning solution
Preparation of 1 % acidic solution of Lactoweekly for circulation cleaning in
the milk analyser:
1. Take the package 100 g concentrated powder chemical Lactoweekly
2. Carefully cut the upper end, paying attention not to spill it.
3. In appropriate vessel (for example bucket) pour 1 l water.
4. Add the powder and then again water up to 10 l.
Then follow the instruction for milk analyser cleaning.
For final cleaning with the syringe it is recommended to use 1% acidic
solution of Lactoweekly, preliminary heated up to 70 ˚C.
Fig. 7 Labels for acidic cleaning chemical Lactoweekly and alkaline
cleaning chemical Lactodaily
Ultrasonic milkanalyser
4.3. Working with the peristaltic pumps
There are two peristaltic pumps in the analyser – 1 for the sample and 1 for
the cleaning.
Fig.8 Peristaltic pumps
Ultrasonic milkanalyser
Fig. 9 Peristaltic pump SL 16
Ultrasonic milkanalyser
5. POSSIBLE MALFUNCTIONS AND ERROR MESSAGES,
TROUBLESHOOTING
In the table below are described the possible malfunctions during the milk
analyser’s exploitation and ways for their repair/remedy. If the problem
persists after all recommended measures are taken, please, connect the
nearest service center.
Error
message
MA
overheated
Accompanied
by a
continuous
sound signal
Empty
Camera
Sample
Overheat
Possible
problem /cause
Overheated milk
analyser
Insufficient
quantity of the
milk sample
sucked in the
system or air in
the sample
Sucked
overheated
sample
Repair/remedy
Immediately switch off the analyser.
Pay attention the analyser to be situated away from
direct sunlight or heating devices.
Wait 5-10 minutes the device to cool down or to be
normalized the ambient temperature and switch it on
again.
The analyser is ready to measure the next sample.
In order to avoid the future appearance of the same
error message, please, check the following:
- The sample is prepared according the
instructions and there aren’t air bubbles in it.
- There is a real suction of the sample after
starting measurement, i.e. it is obvious that the
level of the milk sample in the sample holder
decreases. In other case – there is damage in
the suction system.
- Avoid the end of the suction pipe to be above
the surface of the liquid (not dipped enough).
- Avoid curdling of the milk sample. Clean
immediately if there is a sample curdled in the
system.
- In mode Measurement, after starting the
measurement, remove the sample holder and
see if there is no milk poured back in the
sample holder.
The analyser is ready to measure the next sample.
In order to avoid the future appearance of the same
error message, please, check the following:
-The sample is prepared according the instructions
and its temperature does not exceed the maximum
permissible sample’s temperature.
-Complete the procedure for checking the analyser
in case of error message Empty Camera.
Ultrasonic milkanalyser
6. MAKING CORRECTIONS AND RECALLIBRATION OF THE
DEVICE
At least once monthly check the correctness of the results and need of
corrections and calibration.
In the process of work with the analyser there is a possibility the results to
start differing between the data for some of the measuring parameters when
measured with the milk analyser and the corresponding reference method of
analyses (Gerber for fat, Kjeldhal for proteins etc). In order to establish the
possible discrepancy and to correct the readings of the milk analyser do the
following:
6.1. Taking samples and preparation of samples for checking the
accuracy of the milk analyser, making corrections and recalibration
This is a basic moment for the correct checking the accuracy of the analyser
and for making correct and precise correction and calibration. It is
accomplished according Appendix Taking and preparation of samples for
checking correctness of the milkanalyser, making corrections and
recalibration.
6.2. Determination the type of the discrepancy:
6.2.1. Making measurements
Make measurements with different samples (not less than 3) with known
values of a separate parameter (for example fat content), determined by the
known reference methods of analyses (for example Gerber's method for
determination of fat content). For more accuracy it is recommended among
these samples to be also such with values, close to the lowest and highest
bounds for the measured parameters.
Make 5-time measurement for each of the samples. Calculate the average
value for each sample parameter, without taking into consideration the first
measurement for each sample.
6.2.2. Analyzing the measurement results
Make comparison between the values of the parameter from the reference
sample and measured with the analyser. Make analyses of the difference
received.
Ultrasonic milkanalyser
6.2.2.1. If the received differences are relatively constant value for samples
with different content of the analyzed parameter, it is necessary to make
correction.
For example
М% of the reference samples: 2,20 3,00 3,80 4,60 5,20
М% average when measuring
with the analyser: 2,38
3,17 4,01 4,79 5,42
Difference: 0,18 0,17 0,21 0,19 0,22
Conclusion: the difference is relatively constant value and correction is
possible to be done with – 0,2 % (see Corrections, p. 6.3.3)
6.2.2.2. If the differences are not a constant value it is necessary recalibration
to be done.
For example.
М% of the reference samples: 2,20 3,00 3,80 4,60 5,20
М% when measured with the
analyser: 2,02
2,93 3,76 4,75 5,44
Difference: -0,18 -0,07 -0,04 0,15 0,24
Conclusion: It is obvious that the difference is variable value and
recalibration has to be done (See Recalibration, p.6.4).
6.3. Making corrections
6.3.1. Possible corrections, limits and changing steps
Every parameter from each calibration may be separately corrected. Below is
the table with possible corrections, limits and changing steps:
Parameter Increasing Decreasing Step
FAT 0.95% 0.95% 0.01%
SNF 4.75% 4.75% 0.05%
Density 4.75% 4.75% 0.05%
Lactose 0.95% 0.95% 0.01%
Salts 0.95% 0.95% 0.01%
Proteins 0.95% 0.95% 0.01%
Added water 9.00% 9.00% 1.00%
Sample’s temperature 9.90oС 9.90oС 0.1oС
6.3.2. Preparing the analyser for mode Corrections
Ultrasonic milkanalyser
6.3.2.1. Press the button Enter and without releasing it switch on the power
supply of the device, wait for the starting identification messages and release
the button after the following message appears on the display:
Release button
to start setup
After releasing the button on the display is shown:
MA Setup
followed by possible to be entered by the operator menus:
Special modes
Corrections
Settings
-----------------------------Tests
pH & Co Meter
Accessories
Exit
6.3.2.2. By using buttons “up” ▲ and “down” ▼position on Corrections and
press Enter.
6.3.3. Making correction
6.3.3.1 Determining the correction mode
When starting Corrections, the following appears on the display
Corrections:
Calibration 1
Calibration 2
Calibration 3
--------------------------Temperature
Exit
Ultrasonic milkanalyser
By using buttons “up”▲ and”down”▼position on the corresponding
calibration (for example Correction 1 – cow) and press Enter.
6.3.3.2. Choosing correction parameter
After choosing calibration mode the display shows the following:
Cal1 Correct’s
FAT
SNF
Density
-----------------------------Lactose
Salts
Proteins
Water
-----------------------------Exit
Using the buttons “up”▲ and”down”▼position on the parameter to be
corrected (for example FAT) and press the button Enter.
6.3.3.3. Making correction
After choosing parameter (for example fat) the display shows the following:
FAT Correction
0,05
- OK +
Using the buttons “up”▲ and”down”▼is possible to increase or decrease the
value of the measured parameter in the above pointed limits. Leaving this
mode means saving the correction value and activating it.
6.3.3.4. Making verification
After the corrections are made put the milk analyser in working mode
following the sequence below:
1. Switch off the power supply.
2. Switch on the “POWER” button, which starts the identification
procedure. For a short time the display shows the number of the
software versions, for example:
Ultrasonic milkanalyser
Milk analyser xxx
LCD vers xx
MA vers yy
MA ser. N. xxxx
3. Till the analyser is prepared for work (at about 5 minutes) the following
message is written on the display: “Getting ready”.
4. When the device is ready for work, a beep is heard and the display
shows: “Analyser ready”. The analyser is ready to make analyses in
mode 1 (normally Cow).
5. make several times measurement of reference samples with known
values of the corrected parameter. If the difference between the values
of the parameter from the reference methods and milkanalyser are in
the limits for the parameter it may be considered that the correction is
successfully made.
If the discrepancy between the measurements from the milk analyser and
classical methods is bigger than is necessary to make second correction
according above described way.
If after the second correction the results are unsatisfactory we recommend
making a calibration of the analyser. In dependence of the conditions and
your requirements you may make the calibration using a personal computer
type IBM PC and the company's calibration program or autonomous - by
recalibration.
When making corrections or calibrations be 100% sure in the accuracy of the
reference methods result.
6.4. Recalibrating the milk analyser
6.4.1. Running the analyser in mode Recalibrate
6.4.1.1. Press the button Enter and without releasing it switch on the power
supply of the device, wait for the starting identification messages and release
the button after the following message appears on the display:
Release button
to start setup
Ultrasonic milkanalyser
After releasing the button on the display is shown:
MA Setup
Followed by the possible to be entered by the operator menus:
Special modes
Corrections
Settings
-----------------------------Tests
pH & Co Meter
Accessories
Exit
6.4.1.2. By using buttons “up” ▲ and “down” ▼ position on Settings and
press button Enter.
6.4.1.3. Analogically, position on Recalibrate and press the button Enter.
6.4.2. Making recalibration
6.4.2.1. Determining the calibration mode
After starting Recalibrate, the display shows the following:
Recalibrate
Calibration 1
Calibration 2
Calibration 3
----------------------------Edit samp’s 1
Edit samp’s 2
Edit samp’s 3
Edit FrPoints
---------------------------- Exit
Ultrasonic milkanalyser
Using the buttons “up” ▲ and “down” ▼ position on the corresponding
calibration (for example if you need to recalibrate cow milk, which is assigned
in the milk analyser as Calibration 1 - cow) and press the button Enter.The
following message appears on the display:
Calibration 1
Getting ready
6.4.2.2. Entering values for the separate sample parameters
Wait for the sound signal and the following menu on the display:
Cal1 Samp High
Fat=f.ff
SNF=y.yy
Den=d.dd
-----------------------------Lac=l.ll
Sol=s.ss
Pro=p.pp
Exit
In this display is possible to be entered the results from the milk with high
FAT chemical analyses, which were received by the methods from Appendix
Methods.
For example:
- by using the buttons “up” ▲ and ”down” ▼, choose the needed
parameter to be entered;
- by pressing “Enter” the cursor will mark the number to be changed. For
example: FAT=01.29;
- using the buttons “up” ▲and ”down” ▼, enter the needed value;
- by next pressing of Enter pass towards the next number;
- after completion of entering the needed FAT value, press Enter;
- the cursor returns to its starting position.
Cal 1 Samp.High
Fat=f.ff
SNF=y.yy
Den=d.dd
Ultrasonic milkanalyser
With the button “down” ▼ move the cursor across SNF and analogical to the
above described consequence enter the value for SNF and after that the rest
of the values.
Using menus Edit samp's 1(2, 3) the operator has the possibility preliminary
to prepare the data for the parameters for each recalibration separately or to
check the sample data.
6.4.2.3. Making recalibration with the available samples
After entering the values for the separate parameters of the sample position
the cursor across Exit, press Enter and the following menu appears on the
display:
Recalibrate 1
Put sample High 5
times
Which reminds us to put 5 times the sample with high FAT.
The sample has to be with temperature in the boundaries 15-25°С.
Before each measurement:
1.Stir 2-3 times the milk sample before each measurement by pouring it from
one vessel to another.
2.Pour the needed quantity in the sample-holder and put it in the recess of
the device.
3.Start the measurement.
4. The sample is sucked.
Appears the following menu:
Recallibrate 1
Put sample high 5
times
Samp T=16.8
After the sample is measured, appears the following menu:
Ultrasonic milkanalyser
Recalibrate 1
Put sample High
Cal meas=1/5
Follow the procedure till the 5th measurement.
After 5th measurement completion automatically appears the menu:
Cal 1 Samp Low
Fat = f.ff
SNF=y.yy
Den=d.dd
-----------------------------Lac=l.ll
Sol=s.ss
Pro=p.pp
Exit
Which reminds to enter the values for the sample with low FAT? Enter the
values analogically to the procedure, described in the previous sample. After
entering the last parameter position the cursor on “Exit”, press “Enter” and
the following menu will appear:
Recal 1
Put sample Low 5
times
Make 5 times measurement of the low FAT sample.
After 5th measurement completion automatically appears the menu:
Recal 1
Put sample water
Which reminds for 5-times water measurement? There is no need to enter
values after placing the sample-holder. Measurement starts directly.
Ultrasonic milkanalyser
The used water has to be distilled or boiled.
After the 5
th
measurement appears the menu:
Recalibrated
Analyser ready
This means that the calibration was completed successfully and the analyser
is recalibrated for cow milk, marked as “Calibr 1”.
Switch off the power supply of the device and switch it on again.
The device is ready to work with the new calibration.
If during work the sample’s temperature exceeds the temperature range 1525° С the following message appears:
Temperature out of
range
Wait till the end of the measurement. When the message appears:
Put sample again
Put sample with temperature in the temperature range and continue the
measurement till completion of 5-time measurement.
Ultrasonic milkanalyser
7. STARTING THE DEVICE IN A SERVICE TEST/SETUP
OPERATIONAL MODE. MENUS DESIGNATION
7.1. Starting the device in a service Test/Setup operational mode.
In order to start the Setup of the device the operator has to press the button
Enter and without releasing it to switch on the power supply of the device, to
wait for the starting identification messages and to release the button after
the following message appears on the display:
Release button
to start setup
After releasing the button on the display is shown:
MA Setup
Followed by possible to be entered by the operator menus:
Special modes
Corrections
Settings
-----------------------------Tests
pH & Co Meter
Accessories
Exit
You may move in the menus by using buttons “up” ▲ and “down” ▼.
If by pressing the button Enter you choose a menu, each menu offers new
points/submenus. When Exit is chosen the device leaves the Setup mode
and returns to normal work.
Ultrasonic milkanalyser
Due to continuous device improvement or due to the type of ordered type device
it is possible some of the functions of the analyser to be not active (options not
included). In this case, when trying to enter such function will display the
following message: Not available option
7.2. Menus Function:
7.2.1. Special modes.
Serve for choosing special (technological) working modes. After starting it the
following appears on the display:
Special modes
Calibration
Cycle
Exit
This mode is normally used in production conditions.
7.2.1.2. Calibration mode
In mode Calibration the analyser is ready to make measurement and to send
the received results towards the technological milk analysers calibration
system. For this purpose you need personal computer type IBM PC,
company’s calibration system LSC.EXE and methods for calibration of milk
analysers (see the corresponding documents). To start measurement in this
mode, the operator has to put a sample-holder containing milk sample in the
recess of the analyser and to press the button Enter.
7.2.1.2. Cycle mode
Mode Cycle serves for training the analysers. When you start this mode, the
analyser, without additional commands, sucks the sample, makes the
measurement, pours the sample out in the sample-holder and displays the
received results cyclically.
7.2.2. Corrections
Serves for entering corrections in the measured data. Detailed description in
point 6.3.2 and 6.3.3.
Ultrasonic milkanalyser
7.2.3. Settings.
Serve for assigning different working parameters (modes).
7.2.3.1. Net number.
Serves for assigning the device network number when connecting it in the
production network. The possible numbers are from 0 to 15 including.
After starting this function the display shows the following:
Net number
0
- OK +
By using the button “up”▲ the operator has the possibility to increase the
number, showing the channel’s number, and by button “down”▼, to decrease
it. Pressing the button Enter saves the chosen channel and exits the function.
When connected in the production network each device has to have a
unique number.
7.2.3.2. COM1 mode.
Serves for choosing the working mode of COM1 (RS232 on the rear panel).
Chooses the device towards which the measurement results are send. There
are two possibilities:
- towards a personal computer - PC;
- towards serial printer - Prn.
After staring this function the display shows the following:
COM1 mode:
Prn _
PC OK Prn
Using the button “up”▲” the operator has the possibility to send the results
towards Prn, and by button “down”▼, towards PC. Pressing the button Enter
saves the chosen output device and exits the function.
Forwarding the printer towards COM1 is necessary when connecting
additional external keypad to the analyser. In this case the keypad is
connected to connector Printer, and the printer – to connector RS 232.
Ultrasonic milkanalyser
Forwarding the printer could not be necessary if there is a special cable –
fork-joint (from the company-producer), which allows both the keypad and
serial printer to be connected towards connector Printer. In this case the
connector RS232 is free and may be used for communication with computer
IBM PC type.
7.2.3.3. LCD Setup.
Serves to adjust the backlight of the display. The two parameters may be
changed in two modes:
- fast – for rough adjustment;
- fine – for precise adjustment.
After starting this function the displays shows the following:
LCD Setup:
B. Light fast
B.Light fine
Exit
7.2.3.4.Recalibrate.
Serves for changing definite calibration. Methods are described in point 6.4.
7.2.3.5. Edit FrPoint
Through this menu you have the possibility to enter the basic freezing point
separately for each calibration. For more information, see Appendix Freezing
point. After choosing the menu the following is displayed:
Edit FrPoints
FrPoint Calibr1
FrPoint Calibr2
FrPoint Calibr3
---------------------------- Exit
After choosing freezing point for the calibration, the following is displayed:
Ultrasonic milkanalyser
FrPoint Calibrx
-0.fff
- OK +
Where:
Calibrx - basic freezing point to be edited for chosen calibration;
-0.fff - basic freezing point current value;
By pressing the buttons:
“up”▲ - you may increase the absolute value of the freezing point;
”down”▼ - you may decrease the absolute value of the freezing point;
“Enter” - saves the edited value and exits the menu;
7.2.3.6. Save/Rest Cal.
Through this menu you may save the new calibration in the device or to
restore the old one (factory) calibration. This is necessary in case that you’ve
calibrated the device for cow milk, but after that the device is not measuring
correctly and you decide to restore the factory calibration settings. Position
the cursor across “Restore calibration” and press “Enter”
Possibilities:
Save calibration – saves the chosen calibration in an internal buffer.
Restore calibration – restores the chosen calibration from the internal
buffer.
The procedure Save/Restore is done for each calibration separately.
Current working
calibration (1, 2 or 3)
Internal storing
Save Æ
buffer
Current calibration content is not changed, the analyser continues using it,
but there is a reserve copy in an internal buffer.
Current working
calibration (1, 2 or 3)
Internal storing
Restore Å
buffer
The current calibration is replaced with the calibration from the internal buffer
and the analyser starts working with it. The content of the internal buffer is not
changed.
Ultrasonic milkanalyser
If after recalibration “Save calibration” is pressed the new calibration
settings will be saved over the factory settings. After that is impossible
to restore the factory settings of the calibration. Save the newly made
calibration only if you are sure about its correctness.
7.2.3.7. Settings Page 2.
After this menu is started the display shows the following:
Settings Page2
Final clean Cnt
Auto Print Res
Larg Res En/Dis
Set Calibr Name
Exit
Now there is a possibility one of the following options to be set:
7.2.3.7.1. Final Clean Cnt
Sets the number of cleaning cycles.
7.2.3.7.2. Auto Print Res.
It is possible (if it is needed) to prohibit the automatic printing the measurement
results. If there is external keypad connected, then the results could be printed
by pressing the button 1 from the keypad. It is possible to print out unlimited
number of printouts for one and the same measurement.
7.2.3.7.3. Larg Res En/Dis.
The format of the measurement data send towards the computer is set.
If the option Large Disable, is chosen, then only the main results are send to
the computer – Fat, SNF, Density, Lac, Proteins, Added Water, sample
temperature, device serial number and calibration number.
If the option Enable, is chosen, except the above mentioned parameters also
data for Salts, Freezing Point, pH, Conductivity will be send to the computer. In
this case is necessary the software in the computer to be conformable to the
format of the sent data. After starting the menu, the display shows (for example):
Large Results
No
No OK Yes
Ultrasonic milkanalyser
7.2.3.7.4. Set Calibr Name.
Sets the names of the separate calibrations. The name could be chosen from
the group of predefined calibrations names or to edit a new one. When editing
the new name there is a possibility all ASCII codes to be used, as letters (caps
and normal), numbers and punctuation marks and popular symbols. The
calibration name consists of 8 symbols.
Example:
When it is suitable to us this possibility of the analyser? For example if you have
a device factory calibrated for Cow milk, Sheep Milk and UHT milk, but yоu need
oftenly to measure camel milk. Using the methods, explained in details in
Appendix Methods you may make a new calibration without need to send the
analyser back to the producer for calibration. Using this procedure you may
make calibrations for most oftenly analysed milk and to write down the exact
calibration name, which will be shown on the display and printed on the printer.
After starting this menu the display shows:
Select Calibr
Cal1: Sheep
Exit Yes Next
There are the following possibilities:
With button Exit – to leave the menu.
With button Yes – to confirm the chosen for editing calibration name.
With button Next – to choose the next calibration name for editing.
If a calibration for change or edit of name is chosen, the display shows
(example):
Cal:Sheep
PreDef Exit Edit
There are the following possibilities:
With button PreDef – to choose a calibration name from the list of preliminary
given names.
With button Exit – to leave the menu.
With button Edit – to edit the new calibration name.
Ultrasonic milkanalyser
If a name from the preliminary given names list is chosen, the display shows:
Cal1: Sheep
UHT
Exit Yes Next
There are the following possibilities:
With button Exit – to leave the menu.
With button Yes – to confirm the chosen from the list calibration name.Now the
program returns to the beginning of the menu for setting calibration names.
With button Next – to show the next calibration name from the list.
If it is decided a new calibration name to be edited, the display shows:
Cal1: Sheep
User Edited
Name:
Prev Set Next
There are the following possibilities:
With button Prev – to display the previous ASCII symbol.
With button Set – to confirm the ASCII symbol, shown on the display and
passes to editing the next symbol from the calibration name.
With button Next – to show the next ASCII symbol.
After editing the last (eighth) name symbol, the display shows:
Cal1: Sheep
User Edited
Name:MilkShp
Exit Save
There are the following possibilities:
With button Exit – to leave the menu.
With button Save – to confirm already edited calibration name and to save it in
the device. The program returns to the beginning of the menu for setting
calibration names.
Ultrasonic milkanalyser
7.2.4. Tests.
Start different tests. Possibilities:
7.2.4.1. Test pump.
Starts pump’s test. The number of the completed suction/display cycles is
indicated.
7.2.4.2. Ultrasound.
Test for the ultrasonic system. Used in production conditions.
7.2.4.3. Serial Prn.
Display a short text of a serial printer, connected to COM2 – output with
inscription Printer on the back panel of the device.
7.2.4.4. Set Amplitude.
Serves for ultrasound amplitude adjustment. It is used under production
conditions or by the customer (after sensor change) according the
instructions in the document SetCell.pdf.
Please, use this menu only after reading the above pointed document
SetCell.pdf
7.2.5. pH meter & Co meter
Ph and conductivity measuring are additional possibilities for the analyser
and are optional. Their usage is described in Appendices PH Measurement
and Conductivity Measurement.
7.2.6. Exit
By pressing the button you may leave the program and pass towards another
menu.
Ultrasonic milkanalyser
7.2.7. Summary of milk analyser setup functions
Analyzer Setup
Special
modes
Calibration
Corrections
Calibration 1
Fat
Calibration 2
Fat
Calibration 3
Fat
Temperature
Cond
Settings
Net number
Contrast fast
Recalibrate
Calibration 1
Cycle
Reports
Shut Down
SNF
Density
Lactose
Salts
Proteins
Water
SNF
Density
Lactose
Salts
Proteins
Water
SNF
Density
Lactose
Salts
Proteins
Water
measure
COM1 mode
LCD Setup
Contrast fine
B.Light fast
B.Light fine
Calibration 2
Calibration 3
Edit samp's 1
Edit samp's 2
Ultrasonic milkanalyser
Edit samp's 3
Edit FrPoints
FrPoint Calibr1
FrPoint Calibr2
FrPoint Calibr3
Save/Rest
Cal
Save Calibr 1
Save Calibr 2
Save Calibr 3
Rest Calibr 1
Rest Calibr 2
Rest Calibr 3
Fan Temp
Offs
Settings
Page2
Final clean cnt
Auto Print Res
Larg Res En/Dis
Set Calibr Name
Option Select
Sel Pump Speed
Speed for Cal 1
Speed for Cal 2
Speed for Cal 3
HFSpeed for Cal
OutSample Delay
Reslt
Precision
Fat - Precision
SNF - Precision
Den - Precision
Lac - Precision
Sol - Precision
Pro - Precision
AdW - Precision
Properties
PCB Main Identi
PCB LCD Identi
Tests
Test pump
Ultrasound
Serial Prnter
KeyPad
Displays
Parallel Prn
pH & Co
Meter
Ultrasonic milkanalyser
pH
Calibration
pH
Measuring
pH
En/Disable
pH U Display
pH Test U[V]
Co Meter
Calibr
Co Meter
Test
Co Meter
En/Dis
Accessories
Weight scale
Raw Test
Battery
Measure Bat U
RT Clock
Display Time
Calibration
Measure
On Line En/Dis
Ctrl Enabl/Dis
Adjust Time
Adjust Date
Ultrasonic milkanalyser
8. ADDITIONAL POSSIBILITIES OF THE ANALYSER
8.1. Connecting to 12 V DC power supply.
If there is a need the analyser to work on place without electrical supply
available, then it could be powered by car battery or other 12 V DC external
power supply. Use the 12 V power supply cable (art. number 30030).
8.2. Connecting to IBM PC
The analyser can be connected to IBM PC using the RS232 interface cable
(art. number 30012, Parts and Accessories, point 16). In order to make the
connection: switch off both the milk analyser and PC. Connect the RS 232
cable towards Com. Port 1 and towards the computer. Turn on both analyser
and PC. Now the device is ready to communicate with IBM PC. For more
detailed information regarding milk collection data program see the file
resLS_SupLiters.pdf from the CD, accompanying the device.
8.3. Connecting additional serial printer (option).
The interface connector for the printer is on the rear panel of the device
(Com. Port 2). The printer should be connected towards it. Connect it via
cables, delivered by the company-producer. If the printer is connected directly
to the electrical network, then the analyser and the printer should be
connected to one and the same electrical phase.
Communication parameters: 9600 bps, No parity, 8 bits, 1 stop bit. It’s oneway communication (uses one line) – the analyser only sends and the printer
only accepts data.
8.4. Connecting matrix printer (option).
If the device is working n milk collection center, where work load is heavy,
and there are a lot of results to be printed out, we suggest an option
connecting standard matrix printer (paper expenses would be less, the
reliability better).
Interface connection with the printer is at the rear panel of the analyser
“Parallel printer interface”.
8.5. Connecting and working with external keypad (option).
It is possible external keypad (supplied by the producer of the device) to be
connected to the device, using special cable to the serial printer connector.
In order to connect external keypad to the milk analyser, follow the procedure
below:
1. Connect the keypad towards connector labeled Printer.
2. Connect the printer towards connector labeled RS 232.
3. Forward the printer towards output RS 232, doing the following:
o Press the button Enter (on the front panel of the analyser).
Ultrasonic milkanalyser
o While holding it pressed, switch on the analyser’s power supply.
o Release the button Enter.
o Using the buttons Up/Down choose menu Settings and press
Enter.
o Using the buttons Up/Down choose menu COM1 Mode and
press Enter.
o With the right button (Up) choose COM1 Mode – Prn, press
Enter and leave the menu.
With the external keypad 4 digit identification number of the milk deliverer
may be entered (from 1 to 9999) and quantity of delivered milk in liters (from
0,1 to 9999.9) (accurateness up to 0.1 l). These data entering have to be
completed before starting measurement. Pressing the button Enter on the
keypad will display the following:
Enter Data
Del N:
Now enter the deliverer’s identification number. After pressing Enter on the
external keypad, the display shows:
Enter Data
Del N:xxxx
Liters =
Now, enter how many liters have been delivered and press the button Enter
on the external keypad the following is displayed:
Del N:xxxx
Liters=yyyy.y
Are you sure?
0-No Yes-Enter
Where:
хxxx - entered by the operator identification number of the deliverer
yyyy.y - entered by the operator liters.
Ultrasonic milkanalyser
The operator has two possibilities:
1. To cancel the entered data by pressing the button 0 on the external keypad
and to start entering them again.
2. Confirm the entered data by pressing the button Enter on the external
keypad. The display shows currently chosen calibration. The device is ready
to start measurement. After completing the measurement, the data for the
deliverer are printed out.
8.6. Measuring high fat samples (option).
The standard device measures samples up to 25% fat.
On customer’s request, the device could be produced with possibility to
measure samples up to 50% fat. The customer can choose which calibration
to have this possibility and which not, as well as during the process of
exploitation to change the measuring mode i.e. to pass from measuring
normal fat percentage towards high and vice versa.
What the operator sees during these passes is the difference in the speed of
sucking the sample. For that purpose, the high-fat sample has to be
preliminary heated up to 30С +- 3С.
To choose the mode, follow the sequence below:
Setup->Settings->Settings
Page2->Option
Select->SelPumpSpeed->Speed for Cal x
After which the display shows:
Calibr x
Pump Speed
Normal OK HiFat
By pressing the correspondent buttons the operator can choose the type of
measurement and to exit the menu.
When changing the type of measurement on a calibration is necessary a new
calibration of the device on the new speed to be done. When calibrating
measuring high fat sample, before starting the calibration procedure, the
operator has to choose from the menu:
Setup->Settings->Settings
Page2->Option
Select->SelPumpSpeed-> HFSpeed for Cal
Ultrasonic milkanalyser
By which the device passes in a mode of measuring high fat samples.
This calibration mode is active till the power supply of the device is switched
off i.e. it has to be always set if the device will be calibrated for high fat
measurement.
8.7. Working with embedded accumulator (option).
On customers’ request accumulator could be embedded in the milk analyser.
In this way it could work independently on the electrical network. In this case
the Power switch on the rear panel of the analyser serves for close / open the
electric circuit of the outer power supply. After closing the circuit, in order to
start the analyser, the operator has to press the Start button on the front
panel of the analyser.
Switching off the analyser could be done on one of the following ways:
Through the analyser – by switching the Power button on the rear panel of
the analyser.
Through the software – by using the option Shut Down from the Calibration
and Working mode menus.
After pressing and holding pressed the button Enter (when choosing
calibration), the following is displayed:
Milk selector
Cal1 – Cow
Cal2 – Sheep
Cal3 – UHT
----------------------------Cleaning
Final clean
Shut Down
By choosing the option Shut Down the operator may switch off the power
supply of the analysers.
In case that the external power supply from the electrical network, the
analyzer automatically starts working with power supply from the battery.
Possible working modes with battery:
1. The analyser is powered by the battery, works normally, the display shows
the following message
Battery Powered
Ultrasonic milkanalyser
2. The analyser is in mode Sleep – do not accept any commands, expects
change in the power (supply from switching adapter for starting the battery),
display shows the following
Low Battery
3. The battery power is under the allowed minimum, milk analyser is
automatically switched off. Before switching off, for a short time, the display
shows
Out of Battery
8.8. Embedded real time clock (option).
On customer’s request, a real time clock could be embedded in the device,
showing astronomical time and date. The clock is powered by battery, so it is
independent on power supply of the device. The advantage of this option is
that on the print out with the measurement results are shown also the exact
time, when the measurement is made, for example:
The embedded clock is controlled by the device’s Setup, from the main menu
Accessories, submenu RT Clock. When chosen, the display shows the
following:
Display Time
Ultrasonic milkanalyser
Adjust Time
Adjust Date
Exit
Using these menus, the operator has the possibility to show on the display
the current time and date, and if necessary – to adjust them.
The time is shown in the format:
hh:mm:ss
dd:mm:yy
Exit
where:
hh - the current hour
mm - current minutes
ss - current seconds
dd - current day
mm - current month
yy - current year
Ultrasonic milkanalyser
APPENDICES
APPENDIX 1 METHODS
1. Determination of milk's density
1.1. General
Milk density is defined as relation between the mass of definite milk volume at
temperature 20
temperature 4
Density, alone, could not be used as a control parameter at milk quality
control. Using the density the tentative figures for the SNF and salts could be
determined.
1.2. Sampling and preparation for analyses
Sampling milk or other milk derivatives and their preparation for analyses is
done according corresponding Appendices.
Milk density is determined not earlier than 2 h after milking. The milk must be
with temperature from 10 to 25
Before determination of density the milk must be well stirred. To avoid foam
formation, it has to be carefully poured on the cylinder’s walls. The cylinder
must be slightly tilted.
Before taking the readings the cylinder, with the milk must be placed on an
even surface, facing the light, so the readings could be easily seen.
1.3. Basic principles.
The density of the milk is determined using aerometer, also called lactodensity-meter (milk density meter) and is expressed with a number,
representing milk density meter degrees, decreased 1000 times or only with
milk density meter degrees.
1.4. Necessary devices and reagents
- Aerometer /lacto-density-meter, milk meter/.
- Cylinder – with inner diameter not less than 5 сm, and length, corresponding
to the dimensions of the lacto-density-meter.
- Ammonium with preliminary defined relative density.
1.5. Making the determination:
Dry and clean, the lacto-density-meter is slowly dipped in the milk till division
1,030, and then is left in free-floating state. The lacto-density-meter must not
touch the cylinder’s walls and to be on at least 5 mm from them.
When taking the readings the eyes must be on one and the same level with
the meniscus. The reading is done in the meniscus’ upper end with accuracy
till 0,0005, and the temperature – with accuracy till 0,5
o
С and the mass of equal volume distilled water at
o
С.
o
С.
o
С.
Ultrasonic milkanalyser
The difference between two parallel determinations must be not more than
0,0005.
1.6. Recalculating the values according lacto-density-meter at 20 oС.
If the milk, when determining its density, has temperature, higher or lower
o
than 20
o
С.
Density recalculation towards 20
for every temperature degree over 20
value are added 0,2
С, the readings from lacto-density-meter are recalculated towards 20
О
С is done on the following way:
О
o
for the cow and goat milk and 0,25 o for sheep and
С from the received by the milkmeter
buffalo milk lacto-density-meter degreed or 0,0002, respectively 0,00025
o
towards density; and for every temperature degree under 20
С from the
readings of milkmeter value are deducted 0,2-0,25 lacto-density-meter
degrees or 0,0002, (0,00025) from the density.
2. Determination of fat content in the milk and milk derivatives.
2.1. General
For making analyses are used pure reagents for analyses (pure reagents for
analyses (p.r.a.) and distilled water or water with equivalent purity.
2.2. Sampling
Milk and milk derivatives sampling is done according Appendices Milk
sampling and preparation of samples for analyses ad Sampling and
preparation of samples for verification the accuracy of the milk analyser,
making corrections and recalibration.
2.3. Basic principles.
The method uses dissolving the milk and dairy products proteins with
sulphuric acid with definite concentration in butyrometer and separating the
fat under the influence of amilic alcohol, heating and centrifuging in a form of
dense transparent layer, the volume of which is measured in the graduated
part of the butyrometer.
2.4. Necessary devices and reagents
- Butyrometers for milk, special for skimmed milk and cream;
- Rubber stopples for butyrometers;
- Stand for butyrometers;
- Special pipettes or automatic for milk, sulphuric acid and изоамилов
alcohol from 1, 10 and 11 сm
- Pipettes from 1 and 20 сm
3
;
3
;
Ultrasonic milkanalyser
- Glasses from 25 till 50 сm3;
- Centrifuge for Gerber;
- Water bath;
o
- Mercury thermometers up to 100
- Sulphuric acid with density 1,82 at 20
С with value scale 1 oС;
o
С for determination of fat content
of the milk;
- Isoamilic alcohol for Gerber with density 0,811 to 0,812.
2.5. Making the determination:
Preparation of samples for analyses.
The milk is mixed well in order to become homogenous mixture (if necessary
it is slowly heated up to 35-40
о
20±2
С. The samples from whey and buttermilk are preliminary filtered
through double layer gauze and is then tempered to 20±2
are placed in water-bath at temperature 35 till 40
sample is received and cooled down to 20±2
о
С ) and is carefully shaken and tempered to
о
С. Cream samples
о
С.
о
С, stirred till homogenous
2.6. Making measurement
With butyrometer for milk
For milk, whey and buttermilk.
With automatic or special for acids pipette are measured 10 сm
3
acid with d=1,820 кg/m
butyrometer's walls are piled up 11 сm
at 20 оС in the milk butyrometer. Carefully on the
3
from the prepared sample. The
3
sulphuric
pipette is held till its full drainage.
For cream
From the prepared sample is measured 10 g with error up to 0,001 g and 50
3
сm
water are added. Mixture is well stirred and heated up to 30-35 оС, then
is again stirred and cooled down to 20±2
with the milk sample using sulphuric acid with d=1,789 till 1,790 кg/m
о
С, and the following steps are as
3
.
With butyrometer for cream
For cream
5 g from the sample are measured with butyrometer with error up to 0,0001 g
and then 5 сm
3
кg/m
at 20 оС and 1 сm3 изоамилов alcohol. The butyrometer is closed with
3
water are added, 10 сm3 sulphuric acid with d=1,780 to 1,790
rubber stapple and is shaken till the proteins are fully dissolved.
2.7. Calculating the results
By using milk butyrometer
Milk, whey, buttermilk.
Using the butyrometer's graded scale the grams fat in 100 g product are read
directly. When the milk is curdled, the result is increased with 0,1 g for every
degree.
By using cream butyrometer.
Ultrasonic milkanalyser
Cream
Using the butyrometer's graded scale the fat content in the products is
directly read in percentages.
2.8. Measurement accuracy
By using milk butyrometer
The difference between two parallel determinations could not exceed:
For skimmed milk, whey and buttermilk - 0,05 g for 100 g product;
For cream - 0,5 g for 100 g product;
For milk - 0,1 g for 100 g product;
By using cream butyrometer
The difference between two parallel determinations could not exceed 0,5 g
for 100 g cream.
3. Determination of water content and solids in the milk and milk
derivatives.
3.1. General
The solids represent the fat content, proteins, carbohydrates and salts.
Sampling is done according Appendices Milk sampling and preparation of
samples for analyses ad Sampling and preparation of samples for verification
the accuracy of the milk analyser, making corrections and recalibration.
3.2. Basic principles.
Water content is determined by weight when drying at temperature (102±2)
о
С of the weighted product till constant mass, expressed in grams for 100 g
product.
The solids/dry substance is the mass of the dry remainder, received after
о
dehydration of determined quantity product at temperature (102±2)
С till
constant mass and is expressed in grams for 100 grams of the product.
3.3. Necessary devices and reagents
- Assay balance with loading bounds 200 g and error 0,0002 g.
- Mercury thermometers from 0 to 100
o
scale division 1
- Pipettes from 5 to 10 сm
С;
3
, class II;
- Glass banks with grind stopples with volume 100-200 сm
- Drying-oven with thermal regulator for keeping the temperature (102±2)
О
С and from 0 to 150 oС with value of
3
;
o
С;
- Exicator with silicagel or another hygroscope material;
- Weight plates;
- Peg for the weight plates;
- Glass pods with rounded ends;
- Quartz, sea or river sands.
Ultrasonic milkanalyser
−
3.4. Making the determination:
Sample preparation for analyses.
The milk (whey, cream, and buttermilk) is well shaken. If needed, the sample
о
is heated slowly up to 38-40
С, it is well mixed and cooled down to 20оС.
Mixing and pouring are done at least three times in dry and clean vessel.
3.5. Making the measurement
The weight plate with 20-30 g washed out and tempered sand and glass rod
is dried at 102±2
о
С for 1 h, and then is taken out, covered with the cap,
tempered with exicator (up to 30 min) and the mass is weighted with
3
accuracy up to 0,0005 g. In the weight plate, using pipette, at about 10 сm
milk are poured, covered and weighted. With the help of the glass rod milk is
well mixed with the sand and without a cap is heated on a water-bath till a
homogenous mass is formed. Then the weight plate is put in a drying-oven at
temperature 102±2
о
С, it is dried out for 3 h, it is taken out of the oven,
covered with the cap, tempered in exicator (up to 30 min) and the mass is
weighted. Weight-glass is placed in the drying-oven again and is dried 1 h,
then is taken out, tempered and weighted. This procedure is repeated till the
difference between two consequent measurements becomes not more than
0,004g. In case that at the second or following drying procedure mass
increases, then for the calculation is taken the previous measurement.
3.6. Calculating the results
Water content in grams for 100 g product (milk or milk derivatives), is
calculated by the formula:
=
X
MM
32
100
∗
−
MM
12
Where
М1 - the mass of the plate with the sand and the glass rod, g;
М2 - the mass of the plate with the sand, the glass rod, and the sample
before drying, g;
М3 - the mass of the plate with the sand, the glass rod, and the sample after
drying, g;
The dry substance (Y) is calculated using the formula:
Y= 100 - Х,
Where:
Х is the calculated water content.
3.7. Measurement accuracy.
Ultrasonic milkanalyser
The difference between tow consecutive measurements of one and the same
sample could not be more than 0,2 g for 100 g product.
4. Determination of casein content in the milk.
4.1. General
The methods are based on the Volker's method.
For making the analyses are used pure reactive for analyses (p.r.а.) and
distilled water or water with equal purity.
4.2. Sampling
According corresponding Appendices.
4.3. Basic principles.
Added to the milk formalin liberates acidic residuum from the protein's end
groups, which are titrated with soda caustic solution. The soda caustic
quantity is proportional to the casein in the milk content.
4.4. Necessary devices and reagents
3
- Glass 250 сm
- Pipettes Foll - 25,5 сm
- Pipettes Mor from 1 сm
.
3
.
3
, with division 0,1 сm3.
- Soda caustic p.r.а. - 0,143 n solution.
- Formalin 40% p.r.a - freshly neutralized.
- Phenolphthalein - 2 % solution in 70 % ethyl alcohol.
- Potassium oxalate p.r.а. 28 % water solution.
- Cobalt sulphate p.r.а. 5 % water solution.
4.5. Making the determination:
For cow milk
Reference sample preparation.
20 cm
cm
3
from the measured milk are poured in a glass vessel together with 1
3
3 % water solution of cobalt sulphate. The sample is shaken and a slight
rose color of the solution is received, which serves as a standard in the
research.
4.6. Making the measurement
20 cm
3
from the milk are measured in a glass and a titrated with 0,1 N soda
caustic, using phenolphthalein as an indicator, till the color of the standard
sample is reached. The volume of the used soda caustic is not taking into
consideration.
3
4 cm
38-40 % formalin are added towards the neutralized sample and the
rose color disappears as a result of the liberated carboxylic groups. It is well
Ultrasonic milkanalyser
stirred and titrated with 0,1 N soda caustic, till slight rose color is recovered.
At the second titration the volume of the used soda caustic is measured.
For sheep milk
Casein content in sheep milk is determined on the same way. The only
3
difference is that instead of 4 cm
3
cm
, and the standard/reference sample is prepared with 1 cm3 4 % solution
38-40 % formalin in the milk are added 6
of cobalt sulphate.
4.7. Calculations
The quantity of the 0,1 N soda caustic in cm
3
, used in the second titration,
multiplied by the coefficient 0,7335 is equal to the casein content in the milk
in percentages.
The following tables could be used for quicker readings of casein's
percentage on the base of used cm
3
0,1 N soda caustic:
Table I
Calculation of casein content in the cow milk on the base of used cubic
centimeters 0,1 N soda caustic:
0,1 n NaOH cm3 Casein% 0,1 n NaOH cm3Casein % 0,1 n NaOH cm3 Casein %
3,00 2,20 3,35 2,46 3,70 2,71
3,05 2,24 3,40 2,49 3,75 2,75
3,10 2,27 3,45 2,53 3,80 2,79
3,15 2,31 3,50 2,56 3,85 2,82
3,20 2,35 3,55 2,6 3,90 2,86
3,25 2,38 3,60 2,64 3,95 2,90
3,30 2,42 3,65 2,68 4,00 2,93
Ultrasonic milkanalyser
Table II
Calculation of casein content in the sheep milk on the base of used cubic
centimeters 0,1 N soda caustic:
0,1 n NaOH cm3 Casein% 0,1 n NaOH cm3Casein % 0,1 n NaOH cm3 Casein %
5,40 3,96 6,10 4,47 6,80 4,99
5,45 4,00 6,15 4,51 6,85 5,02
5,50 4,03 6,20 4,55 6,90 5,06
5,55 4,07 6,25 4,58 6,96 5,10
5,60 4,10 6,30 4,62 7,00 5,13
5,65 4,14 6,35 4,66 7,05 5,17
5,70 4,18 6,40 4,69 7,10 5,21
5,75 4,22 6,45 4,73 7,15 5,24
5,80 4,25 6,50 4,77 7,20 5,28
5,85 4,29 6,55 4,80 7,25 5,32
5,90 4,33 6,60 4,84 7,30 5,35
5,95 4,36 6,65 4,88 7,35 5,39
6,00 4,40 6,70 4,91 7,40 5,43
6,05 4,44 6,75 4,95 7,45 5,46
4.8. Measurement accuracy.
Two parallel samples are measured and the difference between them could
not exceed 0,1 %.
The accuracy of the method require the work to be done at place with good
natural illumination, titration to be done evenly, without interruptions, colorless
formalin to be used, preliminarily neutralized with soda caustic and
phenolphthalein indicator.
Formalin titration is easy method, but it is not enough precise. More accurate
results for casein content are obtained using Kjeldhal's method, but it requires
special appliances.
5. Determination of salts in the milk
5.1. General
For the mineral substances in the milk conclusions can me made on the
ashes content.
5.2. Sampling
According Appendices Milk sampling and preparation of samples for analyses
ad Sampling and preparation of samples for verification the accuracy of the
milk analyser, making corrections and recalibration.
Ultrasonic milkanalyser
5.3. Basic principles.
Milk is dried, carbonized and turned to ashes till constant mass. The ashes
received are calculated in percentages.
5.4. Necessary devices and reagents
- Assay balance;
- Crucibles;
- Water-bath or infrared lamp;
- Hot plate or burner;
- Drying-oven with thermal regulator;
- Muffle furnace;
- Exicator;
- Quantity filter.
5.5. Making the determination:
In preliminary tempered and weighted crucible of the assay balance at about
10 g milk is weighted with accuracy up to 0,0005 g. The crucible with the
sample is placed in a water-bath or infrared lamp till the evaporation of milk to
dry state. Then it is carbonized with the burner or on a hot plate, paying
attention not to be splashed out. The crucible is placed in a muffle oven and
turns to ashes slowly, without the sample to be kindled, at temperature 500-
о
550
С till white or grey-white ashes. It is tempered in an exicator and is
weighted till the appointed accuracy. Heating up in the oven is repeated till a
constant mass is received.
5.6. Calculations
Ashes content is calculated using the formula
)(
−
AC
100
ashes
=
∗
)(
−
AB
Where:
А – the mass of empty, tempered crucible, g
В – the mass of the crucible together with the milk, g
С – the mass of the crucible with the received ashes, g
5.7. Measurement accuracy
The difference between tow parallel determinations could not be more than
0,02 %.
Ultrasonic milkanalyser
APPENDIX 2 REPRESENTATIVE SAMPLES FROM MILK AND
OTHER MILK DERIVATIVES FOR MILK ANALYSER’S
CALIBRATION
1. General
The samples used for analyser’s calibration have to be representative for the
corresponding milk type and have to be with known quality parameters: fat in
percentage, SNF in percentage, density, lactose in percentage, total protein
in percentage and salts in percentage. Changes in the analyzed parameters
in the samples have, if possible, to cover the whole measuring range – i.e.
used samples to be with low, middle and high content of the analyzed
components.
The exact value of the parameters is decisive for correct and accurate
calibration, because if the parameters are not set correctly during calibration
the same parameter will not be measured correctly.
2. Necessary quality parameters values determination
For more precise determination of above listed quality parameters of the milk
and its derivatives is advisable they to be examined in an authorized
laboratories, using the corresponding arbitration methods for this purpose.
2.1. Laboratory methods
2.1.1. Determination of fat content
Determination of fat content in the milk and its derivatives (cream, whey,
buttered milk) is one of the most important analyses in the dairy production
and milk processing. According this parameter the payment schemes are
made and it is observed from the point of view correct production process
and the basic economy balances are made with its help.
А/ Röse-Gottlieb method
The fat content is determined using the gravimetric method, fat extraction
from ammonia-alcohol milk solution using diethyl and petroleum ether,
evaporation of the solvent and weighting the residuum.
B/ Gerber method
The proteins in the milk and dairy products are dissolved with sulphuric acid
with definite concentration in butyrometer and the fat is separated under the
influence of amyl alcohol, heating and centrifuging in a form of dense,
Ultrasonic milkanalyser
transparent layer. The volume of this layer is measured in the divided part of
the butyrometer.
This is quick, easy method with sufficient accuracy. We recommend it for
usage. For more detailed description see Appendix Methods.
2.1.2. Milk density determination
А/ With picnometer and Mor-Vestval scales
This is the most exact method for determination of milk and its derivatives’
density.
B/ with aerometer (lacto-density-meter)
Compared with the above method this is quick and easy readable with
satisfactory accuracy. We recommend it. For more detailed description see
Appendix Methods.
During the lactation period and under the influence of different zoo
engineering factors the density of the different milk kinds varies in the
following bounds:
Milk kind Minimum Maximum Average
Cow 1,027 1,033 1,030
Buffalo 1,026 1,032 1,029
Goat 1,027 1,033 1,030
Sheep 1,031 1,040 1,034
2.1.3. Determination of total proteins
А/ Kjeldahl method
Heating with concentrated sulphuric acid in the presence of catalyst
mineralizes a definite volume of the milk sample. The liberated ammonium
combines with the sulphuric acid and forms ammonium sulphate. After adding
surplus soda caustic ammonium is liberated. When distilled it combines with
the boronic acid. The quantity of the combined ammonium is determined by
titration with acid with determined titer. From the combined with the
ammonium acid the initial nitrogen content is determined, and also the
proteins in the milk.
B/ Titration with formalin
Formalin, added to the milk, combines with the amino group in the protein’s
molecule and forms methyl groups, which have no alkaline reaction. Milk
acidity increases by the liberated carboxylic groups, which are titrated with
soda caustic solution. The used volume soda caustic is proportional to the
protein content in the milk.
Ultrasonic milkanalyser
2.1.4. Determination of casein content in the milk
А/ Kjeldahl method
The total nitrogen content in the milk is determined. Casein is precipitated
with acetic acid (acetate buffer) and is filtrated. The content of nitrogen in the
filtrate is determined. Casein content is the difference between the two results
for nitrogen using the Kjeldahl’s method.
B/ Titration with formalin
More details for this method – see Appendix Methods.
2.1.5. Determination of salts in milk.
For the salts in milk and its derivatives is judged by its ashes content. Milk
dries, becomes carbonized and turns to ashes till constant mass. The ashes
received are calculated in percentage.
2.1.6. Determination of solids in milk
Solids describe the content of fats, proteins, carbohydrates and salts. Its
value may be used for determination of each of these parameters in case of
known other values.
Salts are determined by drying till constant mass – see Appendix Methods.
2.2. Express methods by using another milk analysers
It is possible another device to be used for determination of some of the
quality parameters of milk and its derivatives samples, intended for
calibration, but it has to be noted that it is possible incorrect values to be
received, that’s why it is necessary to be completely sure in the accuracy of
their readings.
Usage of Milkoscan and other milk analysers based on the infrared
measurement principle.
By using it the fat, lactose and protein content may be determined. Problem
may arise with determination of salts and SNF. This is due to the impossibility
of the infrared method to determine the solids and in order to receive the
solids in the sample their meaning is accepted as a constant.
Ultrasonic milkanalyser
APPENDIX 3 MILK SAMPLING AND PREPARATION OF
SAMPLES FOR ANALYSES
1. General
Milk sampling and qualification of raw, thermally treated milk and its
derivatives (cream, whey, buttermilk etc.) is accomplished for every separate
homogeneous batch. As homogeneous batch is accepted:
- Milk, delivered by a separate producer (an individual farm, farm etc.),
and received from one kind of animals after their complete milking,
independently from the number of milk-cans and tanks.
- Milk, received from one or several farms or milk collecting centers, but
delivered in a joint vessel.
- In the enterprise – from one and the same kind raw milk poured in one
vessel.
- For cream, whey, buttermilk etc. – produced as a result of milk
processing and its derivatives from one and the same kind and quality,
poured in a separate vessel.
Milk is qualified not earlier than 2 hours after milking.
When the milk is frozen it has to be warmed up to 10-15
according the below-described procedure.
A sample is taken from every separate vessel proportionally to the quantity of
the milk in it. Samples from the different vessels are mixed well and from the
received medial sample are taken 200 - 250 cm
3
for accomplishing the
needed analyses.
2. Stirring the milk and its derivatives before sampling
Milk stirring
It is a very important condition for receiving exact results. Before taking
samples from big vessels the milk (fresh or thermally treated, whole-milk or
whipped) has to be well stirred for no less than 5 min., by vertical and circular
slow movements. Mixing spoon with long handle is used, allowing the lowest
layers of the liquid to be reached.
The milk in the milk-cans is stirred 5 to 8 times from the surface to the bottom
and reverse with slow circular movements.
Cream stirring
Due to the fact that the cream is significantly thicker liquid than the milk and
contains high percentage fat it has to be preliminary very well stirred from the
surface to the bottom with reciprocation movements at about 20-25 times.
Whey and buttermilk stirring
It is analogical to milk stirring.
o
С and stirred
Ultrasonic milkanalyser
3. Sampling
Samples from milk, whey or buttermilk are taken with metal or glass pipe (dry,
clean and stainless-steel) with diameter at about 10 mm, which is slowly
dipped till the bottom of the vessel and its upper end remains open. In this
way it is filled with milk simultaneously with its dipping. When the pipe is
taken out of the vessel its upper end has to be tightly closed with a thumb.
For a bigger reliability of the analyses results it is recommended the quantity
of the taken sample to be no less than 200 ml.
Cream sample is carefully well stirred in order not to form foam. For taking a
medial sample from milk-cans and tanks a sample pipe is used. Stuck to its
outer surface cream has to be removed by using filter paper, napkin or clean
cloth, preventing in this way the proportionality between the samples and the
total amount of the cream to be disturbed.
4. Sample preservation
The vessels where the samples will be put have to be clean, dry, glass, metal
or from other suitable material, to be tightly closed with rubber or other
stopples. The stopples not to absorb water and fat and not to influence the
analyses sample content.
In summer the sample fills up to the top the vessel, but in winter – at least 3/4
from the vessel’s volume. Each sample for analyses has to be labeled and
described in a way not allowing to be mixed up.
The samples are stored in conditions, assuring temperature, corresponding to
o
the requirements for storing such kind of product (advisable – 1
С).
If there is a need of longer sample storing they have to be preserved; the
most commonly used preservative is potassium dichromate (K
2Cr2O7
) - 1 g
for 1 000 ml. The samples have to be stored in a cold and dark place after the
preservation. Have in mind that during the analyses the results for SNF% will
be increased with 0,1 %. After adding the preservative the sample has to be
well stirred.
Do not make analyses if the acidity of the milk is more than 25oT for cow and
28 oT for sheep milk.
5. Preparing the samples for analyses
Milk – raw and thermally treated
Ultrasonic milkanalyser
When examining samples taken immediately before analyses and shortly
stored, the milk is poured several times from vessel to vessel in order to
distribute the fat content uniformly. To avoid foam formation or separation of
milk fat, the samples have to be carefully poured using the walls of the
vessels, as they are tilted slightly. For a better mixing the sample it has to be
poured at least 3 times. When needed the same is tempered to the
temperature within the measuring range.
If there is fat stuck on the walls of the vessel and the stopple (when the
samples were stored for a long time), the milk has to be slowly heated up to
o
35-40
C. At the same time it has to be slowly shaken. The cream, stuck to
the walls of the vessel is removed. The sample is poured several times and is
cooled down (advisable up to 20
o
С).
If there is separated liquefied fat or white particles with irregular form on the
vessel’s walls reliable results could not be received.
Whey
Before making analyses the whey sample is filtered through double sheet
gauze put over the glass funnel in order to separate the fat grains get into
liquid by incidence and if it is needed the sample is tempered and carefully
stirred.
Buttermilk
Before making analyses the buttermilk sample is filtered through single sheet
gauze put over the glass funnel in order to separate the big protein particles
and if it is needed the sample is tempered and carefully stirred.
Cream
o
The sample is slowly warm up to 35 – 40
С in water bath. The fat is
dispersed wholly by carefully shaking and if necessary, by stirring with glass
stick. The sample is poured from vessel to vessel several times and is cooled
o
down (advisable to 20
С). If after this procedure the sample is not
homogenous, the measurement is not carried out.
Sample for analyses is prepared from homogenized cream by diluting it with
distilled water in degree, sufficient for the components of the diluted cream to
be reached in the measuring range of the analyser.
Ultrasonic milkanalyser
APPENDIX 4 SAMPLING AND PREPARATION OF SAMPLES
FOR VERIFICATION THE ACCURACY OF THE MILK
ANALYSER, MAKING CORRECTIONS AND RECALIBRATION.
1. Necessary consumables and devices
- Distilled water;
- Minimum 3 milk samples with known content of fat, SNF, protein,
density, lactose, solids;
- Heating water bath;
- Cooling water bath or chamber;
2. General
Milk sampling and storage of samples of raw, thermally treated milk and its
derivatives (cream, whey, butter-milk etc.) aiming verification the accuracy of
the analyser, making corrections and recalibration is accomplished following
the recommendations below:
- Sample to be taken from homogeneous batches, observing all the
requirement;
- The sample’s volume to be enough for making minimum 5
measurements for each sample or not less than 0.5 l;
- The samples to correspond to the standard physic-chemical and
microbiological requirements, to be pure, without admixtures, without
added cleaning or other unusual substances and without falsifications;
- Do not use samples with total acidity of milk more than 17
- Vessels, where the samples will be handled have to be clean, dry, glass,
metal or other suitable material, to be tightly closed with rubber or other
stopples. The stopples not to absorb water and fat and not to influence
the analyzed sample content;
- Till the start of the analyses the samples are stored in conditions,
assuring preservation of their content and quantities (advisable low
temperature – 1-3
o
С).
For longer storage of the samples a preservative is added as was already
described in p.9.1.1, and then the sample has to be well stirred.
3. Representative Samples
The samples have to be representative for the corresponding milk type.
Changes in the analyzed parameters in the samples have, if possible, to
cover the whole measuring range – i.e. used samples to be with low, middle
and high content of the analyzed components.
o
T;
Ultrasonic milkanalyser
Exemplary recommended values:
Cow milk
Parameter Low value High value
% fat content 2,00 6,00
% Solids-Non-Fat content 8,00 9,00
The Lactose percentage content (4,0-5,5; average-4, 7), Protein (2,00-4,00;
average-3, 3), salts (0,7-0,8) is proportional to the SNF content. When
preparing samples these values vary within limited bounds.
Sheep milk
Parameter Low value High value
% fat content 5,50 10,00
% Solids-Non-Fat content 9,00 11,50
The Lactose percentage content (average - 4,6), Protein (average - 5,8), salts
(average - 1,0) is proportional to the SNF content. When preparing samples
these values vary within limited bounds.
Buffalo milk
Parameter Low value High value
% fat content 5,50 10,50
% Solids-Non-Fat content 9,00 11,00
The Lactose percentage content (average - 4,7), Protein (average - 4,3), salts
(average - 0,8) is proportional to the SNF content. When preparing samples
these values vary within limited bounds.
Goat milk
Parameter Low value High value
% fat content 2,00 6,00
% Solids-Non-Fat content 8,00 9,00
The Lactose percentage content (average - 4,6), Protein (average - 3,7), salts
(average - 0,8) is proportional to the SNF content. When preparing samples
these values vary within limited bounds.
Ultrasonic milkanalyser
Cream
Parameter Low value High value
% fat content 8,00 20,00
% Solids-Non-Fat content 2,50 5,00
The cream samples are diluted with distilled water. Degree of dilution is 2-3
times, in dependence of the initial fat content in the cream.
Whey
Parameter Low value High value
% fat content 0,20 0,80
% Solids-Non-Fat content 5,00 7,50
The content of fat and SNF in the whey depends on the kind of the dairy
product as a result of which the whey is received.
4. Samples preparation
Milk – raw or thermally treated
For raw milk sample with average content of the analyzed components is
advisable to be used milk, collected from at least 10 animals from the most
commonly met breed in the region where the analyser will be functioning.
Low fat and high fat samples are prepared on the following way:
Available fresh or thermally treated milk is poured in a separating funnel,
which is place in a refrigerator for at least 12 hours at temperature 4 - 6 °С in
order to stratify. For a bigger stratification a longer time is required.
The layer at the bottom is poured in a vessel. It is well mixed by pouring it
from vessel to vessel and is warmed up to 40 °С in a water bath.
The upper layer is poured in another vessel.
Using the certified methods the density and the concentration of the analyzed
components - fat, protein, SNF, lactose, salts are determined.
The analyser’s accuracy depends only on the correctness of the chemical
analyses of the components in the samples and the normal acidity during
calibration!
It is recommended the first cow milk sample with low fat content to be with
the following parameters:
Ultrasonic milkanalyser
1.8-2% FAT; 8.7-9% SNF; 3,3-3,5 % Protein; 4,8-4,9% Lactose; 0,75 Salts;
3
1030-1033 kg/m
Density.
The second cow milk sample with high fat content to be with the following
parameters:
5-5,5% FAT; 8.4-8,79% SNF; 3,1-3,2% Protein; 4,6-4,7% Lactose; 0,7 Salts;
1028-1029 kg/m
3
Density.
Samples with medial values of the separate parameters are received by
mixing the two boundary values in a definite proportion.
Preserve the samples, using above described method for their longer
storage.
When using samples, stored shortly, preliminary pour the sample from one
vessel to another in order to distribute the milk components evenly paying
attention not to form foam in the sample.
When the samples are stored for a longer period it is recommended to warm
it up to 35-45 °С, and the vessel to be shaken carefully. In case that there is a
cream stuck on the vessel’s surfaces – remove it. The sample is poured from
vessel to vessel several times and is cooled down (advisable to 20 °С /.
If there is separated liquefied fat or white particles with irregular form on the
vessel’s walls this sample could not be used.
Whey and buttermilk
The samples are poured several times from vessel to vessel and if needed
gradual heating with stirring with cooling down is done.
Cream
The sample is slowly warmed up to 35 – 40 °С in water bath. The fat is
dispersed wholly by carefully shaking and if necessary, by stirring and
pouring it from vessel to vessel till its full homogenization.
From homogenized cream is prepared sample for analyses by diluting it with
distilled water in degree, sufficient for the components of the diluted cream to
be reached in the measuring range of the analyser.
5. Advisable scheme for independently determination the content of
different parameters in milk and its derivatives
When is not possible to use the help of authorized laboratories and above
mentioned milk analysers we recommend you to follow the scheme:
Ultrasonic milkanalyser
−+∗
−+∗
5.1. For cow milk (whole milk, low fat, skimmed milk) and UHT milk
Determination of fat content – Gerber’s method, described in Appendix
Methods.
Density determination – using aerometer, described in Appendix Methods.
SNF determination – by formula – p. 3.2.3.1.B
Determination of Lactose content – by formula – p.3.2.3.2.А
Determination of salts content – by formula – p. 3.2.3.3.А
Total protein content determination – by formula – p. 3.2.3.4.А
Example: Determination of the quality parameters for two samples cow milk
(low fat and high fat), obtained and prepared according p. 2.3.1 and 2.4.1.
– determine the fat content in the samples, using the Gerber’s method
First
(p.3.2.)
Suppose that for the first sample the result is 2,0 %F, for the second – 5,9
%F.
Second
– determine the milk density, using aerometer (p.3.1.)
Suppose that the results are 1,0316 for the first sample and 1,0274
for the second
Third
– Calculate the SNF content using the formula (p.3.2.3.1.B)
=SNF
378,0
0316,1/1001000,2075,0
=
%50,8
=SNF
378,0
0274,1/1001009,5075,0
=
%23,8
Fourth
– determine the lactose content by the formula (p.3.2.3.2.А)
Lact. = SNF * 0,55 = 8.50 * 0.55 = 4.67 %
Lact. = SNF * 0,55 = 8.23 * 0.55 = 4.53 %
– determine the salts content by formula (p.3.2.3.3.А /
Fifth
Salts = SNF * 0,083 = 8.50 * 0.083 = 0.71 %
Salts = SNF * 0,083 = 8.23 * 0.083 = 0.68 %
Sixth
– determine the total protein content by formula (p.3.2.3.4.А)
Proteins = SNF * 0,367 = 8.50 * 0.367 = 3.12 %
Proteins = SNF * 0,367 = 8.23 * 0.367 = 3.02 %
So, when calibrating the milk analyser we’ll use samples with the following
parameters:
I Ist sample
(low fat)
II nd sample
(high fat)
Ultrasonic milkanalyser
−
+
−+∗
milk fat 2,00 5,90
SNF 8,50 8,23
density 1,0316 1,0274
lactose 4,67 4,53
salts 0,71 0,68
proteins 3,12 3,02
5.2. For sheep milk
Determination of fat content – Gerber’s method, described in Methods p. 3.4.
Density determination – using aerometer, described in Methods p. 3.3.
SNF determination – by formula – p. 3.2.3.1.B
Determination of Lactose content – by formula – p. 3.2.3.2.А
Determination of solids/salts content – by formula – p. 3.2.3.3.А
Total protein content determination – by formula – p. 3.2.3.4.А
Example: Determination of the quality parameters for two samples sheep
milk (low fat and high fat), obtained and prepared according p. 2.3.1 and
2.4.1.
– determine the fat content in the samples, using the Gerber’s method
First
(p.3.2.)
Suppose that for the first sample the result is 5,6 %М, for the second – 9,8
%М.
Second
– determine the milk density, using aerometer (p.3.1.)
Suppose that the results are 1,0352 for the first sample and 1,0300
for the second
Third
– Calculate the SNF content using the formula (p.3.2.3.1.B)
=SNF
∗
378,0
0352,1/1001006,5075,0
=
%11,10
=SNF
378,0
0300,1/1001008,9075,0
=
%65,9
Fourth
– determine the lactose content by the formula (p.3.2.3.2.А)
Lact. = SNF * 0,45 = 10.11 * 0.45 = 4.55 %
Lact. = SNF * 0,45 = 9.65 * 0.45 = 4.34 %
Fifth
– determine the solids content by formula (p.3.2.3.3.А /
Solids = SNF * 0,075 = 10.11 * 0.075 = 0.76 %
Solids. = SNF * 0,075 = 9.65 * 0.075 = 0.72 %
Sixth
– determine the total protein content by formula (p.3.2.3.4.А)
Proteins = SNF * 0,475 = 10.11 * 0.475 = 4.80 %
Proteins = SNF * 0,475 = 9.65 * 0,475 = 4.58 %
Ultrasonic milkanalyser
So, when calibrating the milk analyser we’ll use samples with the following
parameters:
I Ist sample
(low fat)
milk fat 5,60 9,80
SNF 10,11 9,65
density 1,0352 1,0300
lactose 4,55 4, 34
salts 0,76 0,72
proteins 4,80 4,58
5.3. For wheat, buttermilk and cream
Determination of fat content – Gerber’s method, described in Methods p. 3.4.
Density determination – using aerometer, described in Methods p. 3.3.
SNF determination – using drying - p. 3.3. and formula – p. 3.2.3.1.А
II nd sample
(high fat)
Ultrasonic milkanalyser
−+∗
APPENDIX 5: EASY CALIBRATION OF THE MILK ANALYSER
BY CALCULATING THE BASIC PARAMETERS VIA FORMULAS
DETERMINATION OF THE BASIC PARAMETERS IN THE MILK SAMPLE
BY USING FORMULAS IS NOT AS PRECISE AS USING THE ARBITRARY
METHODS, BUT IS SUITABLE FOR USAGE IN FIELD WORK.
5.1. Determination some of the parameters by formulas
There is dependence between the different parameters in milk and its
density, which may be expressed with mathematical equation. On this base
different formula, tested and confirmed by the classical laboratory methods
for analyses, are developed. We recommend the following:
5.2. SNF determination.
For determination of SNF the correlation dependence exists between the
milk’s density, fat and SNF in the milk. When the density and the fat are
known, the SNF can be calculated.
There are several formulas with different applicability.
А/ When the salts and fat are known
SNF is calculated by subtracting the fat percentage from the salts.
SNF = Salts – F (%)
Where
Salts – salts in (%),
F – fat content in (%),
This formula is used for determination of SNF in whey, buttermilk, and cream.
B/ Known quantity of fat and density (most commonly used method when
maximum accuracy is needed).
We recommend the following formula:
SNF
=
378,0
This is a universal formula and actual for milk of almost all kind of cows and
sheep all over the world.
/100100%075,0 densityF
Ultrasonic milkanalyser
5.3. Determination of lactose content
We recommend the following formulas:
А/ for cow milk
Lact. = SNF * 0,55 (% )
Where
SNF – content of SNF in percentages (%),
0,55 – constant coefficient.
B/ for sheep milk
Lact. = SNF* 0,45 (% )
Where
SNF –solids-non-fat content in percentages (%),
0,45 – constant coefficient.
This is an actual coefficient for sheep breeds on the territory of the Balkan
Peninsula.
5.4. Determination of salts content
We recommend using the following formulas:
А/ for cow milk
Salts = SNF* 0,083 (% )
Where
SNF – solids-non-fat content in percentages (%),
0,083 – constant coefficient.
B/ for sheep milk
Salts = SNF * 0,075 (% )
Where
SNF – solids-non-fat content n percentages (%),
0,075 – constant coefficient.
Ultrasonic milkanalyser
This is an actual coefficient for sheep breeds on the territory of the Balkan
Peninsula.
5.5. Determination of total proteins content
We recommend using the following formulas:
А/ for cow milk
Protein = SNF * 0,367 (% )
Where
SNF - solids-non-fat content in percentages (%),
0,367 – constant coefficient.
B/ for sheep milk
Protein = SNF * 0,475 (% )
Where
SNF – solids-non-fat content in percentages (%),
0,475 - constant coefficient.
This is an actual coefficient for sheep breeds on the territory of the Balkan
Peninsula.
Ultrasonic milkanalyser
APPENDIX 6 FREEZING POINT DETERMINATION
1. Methods for determination.
The milk analyser determines the freezing point of each sample and the
quantity of added water. The milk analyser does not measure the freezing
point, but calculates it from the components it depends on. The basic
components in the milk are water, solids, lactose, FAT, proteins, minerals
(salts) and acids. The freezing point depends only on the diluted in the milk
components and quantity of the solvent (in the milk it is water). The ultrasonic
technology allows direct measurement of FAT, proteins, lactose + salts (the
soluble components, only influencing the freezing point), and the quantity of
the solvent in % is determined by 100 % – total solids %, total solids = lactose
% + FAT % + proteins % + salts % + acids %.
Without understanding the meaning of the freezing point – determined or
shown from the milk analyser added water result easily may lead to a mistake
for the value of this parameter.
2. The basic freezing point.
Milk freezes at lower temperature than water. The average freezing point of
the raw milk in the most regions is at about -0,540°С. The average reading
for your region is called “basic” freezing point.
The freezing point of milk is a “physiological constant”. This does not mean
that it will not vary. In fact feed, breed, season, time of lactation, climate,
whether the sample is taken at the beginning, middle or end of lactation – all
these factors will have an effect on the freezing point of the individual sample.
This means that there is an average value of all these numbers. The more
samples used in obtaining this average, the more reliable it is as a base. Or
the basic freezing point is an average of freezing points of milk, taken from
many cows. When a laboratory checks a producer, it is only comparing the
average of the producer’s cows against a larger area average.
The Health authorities establish the basic freezing point or agriculture
departments in some regions, sometimes by universities, separate dairy
producers, or their associations. Frequently, tolerances have been
established on top of a basic freezing point to allow some variations in the
milk as well as device or operator variations.
Without mentioning the basic freezing point, the Association of Official
Analytical Chemists now recommends an upper limit freezing point at 0,525°C (2,326 standard deviations above the most recently determined
North American average of –0,5404°C), below which there will be at 95%
Ultrasonic milkanalyser
confidence that will show 99% of all freezing point determinations on milk
without added water:
“if the freezing point is –0,525°C or below, milk may be presumed to be free
of water or may be confirmed as water free by tests, specified below. If the
freezing point is above –0,525°C, milk will be designated as “presumptive
added water” and will be confirmed as added water or added water free by
tests specified below. Evaluate extreme daily fluctuations in the freezing point
of herd, pooled herd, or processed milk for presence of added water”.
“Presumed added water”, as described above, must be “confirmed” by means
of tests on authentic milk samples obtained as specified in the АОАС
METHODS.
After determination the freezing point of your sample via the milk analyser,
the added water is calculated using the following formula:
AddedWater
Where:
FrPo
−
int
=
intint
FrPoFrPo
Base
CalcBase
[%]100
∗
FrPointBase is the basic freezing point
FrPointCalc is measured freezing point
Note:
If the freezing point is not correctly determined, the result for the added water
is not valid. In this case results for FrPoint and AddWater are not shown on
the display and on the printout from the printer. If the density of the measured
sample is 0, the result for AddWater is not valid and is also not shown on the
display and the printouts.
Sample:
First variant
If you’ve entered for milk analyser basic freezing point -0.520°C (according
article 5.9 of the EU Milk Hygiene Directive 92/46/ЕЕС), measured freezing
point –0.540°C, using the above pointed formula you’ll receive –3,8%.
Because it is not possible the added water to be negative value, the milk
analyser indicates 0% added water. The reason for this is the tolerance in the
basic freezing point, reasons for which are described below.
If in the same milk we add 3,8% water, and the basic freezing point is the
same, the milk analyser will measure freezing point –0.520°C, and will
indicate again 0% added water.
Second variant
Ultrasonic milkanalyser
If you’ve entered for the device basic freezing point –0.540°C, measured
freezing point –0.540°C, the milk analyser will indicate 0%. When you add
3,8% water, the device will indicate 3,8%-added water.
From the above mentioned follows that it is very important to enter correct
basic freezing point in the device.
The device’s results for added water may give information about doubt of
added water in the milk and the exact value of this added water may be
determined after a “cowshed sample” is taken and the result for the freezing
point, measured by the milk analyser of the “cowshed sample” is entered as
basic freezing point in the formula for calculation of added water.
Then the result from this formula will give us the absolute value of the added
water for the corresponding milk supplier.
Ultrasonic milkanalyser
APPENDIX 7 PH MEASURING (ONLY FOR DEVICES WITH
EMBEDDED FUNCTION)
1. General information
PH probe is a unit, measuring the solution acidity or alkalinity degree. It is
measured on scale of 0 to 14. The term pH is derived from "p", the
mathematical symbol for the negative logarithm, and "H", the chemical
symbol of Hydrogen. The formal definition of pH is the negative logarithm of
the Hydrogen ion activity.
2. pH Electrode
For pH measurement the milk analyser needs a combination electrode,
compatible with most pH electrodes that have BNC connectors and zero
potential (the pH where the mill volt output of the electrode equals 0) near 7
pH.
2.1. Electrode part
The electrode is the most important part of the pH measurement. The
electrode glass membrane is fragile and must be handled with care. To
protect the glass membrane and to maintain activation, a protective rubber
cap containing a suitable storage solution covers the glass membrane.
2.2. Electrode care & Electrode maintenance
pH Electrodes are susceptible to dirt and contamination and need to be clean
regularly depending on the extent and condition of use. At no time should one
touch or rub the glass bulb as this causes the build-up of electrostatic charge.
2.3. Storage
For best results, always keep the pH bulb wet. An optimal storage solution for
combination electrode is pH 4 buffer with 225 grams of KCl per liter. Table
salt, NaCl, can be used if KCl is not really available. Other pH buffers or tap
water are also acceptable storage media, but avoid storage in de-ionized
water. The protective rubber cap filled with the buffer solution provides ideal
storage for long periods.
2.4. After Use
After measurement is completed, follow the sequence below for storage.
- Wash the electrode and reference junction in de-ionized water.
- Close the refilling hole by returning its rubber sleeve or stopper cap.
(Necessary for only refillable electrode).
Ultrasonic milkanalyser
- Store the electrode as mentioned above (see section Storage).
2.5. Electrolyte Replacement (for refillable electrode only).
The reference electrolyte needs to be refilled when the electrode has been
used for a long period, or when the internal electrolyte has dried up. To
accomplish this, follow the procedure described below.
- Remove the protective rubber cap or sleeve;
- Remove the protective rubber sleeve to expose the filling port of the
electrode;
- Remove the old reference electrolyte with a syringe;
- Fill the new reference electrolyte.
2.6. New electrolyte preparation:
- Open the KCl container;
- Add in de-ionized water until it reaches the level of 20 ml;
- Close the container and shake it to dissolve the KCl;
- Add in fresh electrolyte until it reaches the level of the refilling port. The
reference electrolyte used should be 3M(Mol) KCl;
- Replace the rubber sleeve.
2.7. Re-use the electrode.
- Rinse the liquid junction with de-ionized water.
If these steps fail to restore normal electrode response, you may attempt to
rejuvenate it (See: Electrode Rejuvenation).
2.8. Electrode cleaning
Electrodes which are mechanically intact can often be restored to normal
performance by one or combination of the following procedures.
- Salt deposits:
Dissolve the deposit by immersing the electrode in tap water for ten to fifteen
minutes. Then thoroughly rinse with de-ionized water. Wash the electrode pH
bulb in a little detergent and water. Rinse electrode tip in with de-ionized
water.
- Oil/Grease films:
Wash electrode pH bulb in a little detergent and water. Rinse electrode tip
with de-ionized water.
- Clogged Reference Junction:
Ultrasonic milkanalyser
pH electrodes have junction, which allows the internal fill solution of the
measuring electrode to leak out into the solution being measured. The
junction can become clogged by contamination in the solution. If a clogged
junction is suspected it is best to clear the junction.
Heat up the diluted KCl solution to 60-80°C. Place the sensing part of the pH
electrode into the heated KCl solution for approximately 10 minutes. Allow the
electrode to cool while immersed in some unheated KCl solution.
- Protein Deposits
Prepare 1% pepsin solution in 0.1 M HCI. Allow the electrode to stand in this
solution for five to ten minutes. Rinse the electrode with de-ionized water.
2.9. Electrode activation
Generally, if the procedure of storage and maintenance had been closely
followed, the electrode can
be used immediately. However, should the electrode response become
sluggish, it may be possible that the bulb has dehydrated.
The bulb can be dehydrated by immersing the electrode in an ideal storage
solution (e.g. buffer pH 4 solution) for 1-2 hours. If this fails, the electrode
may require re-activation. If the above procedure does not reactivate the
electrode to acceptable status, try rejuvenation the electrode by following the
procedure outlined below.
2.10. Rejuvenation Procedure
Dip and stir the electrode in freon or alcohol for 5 minutes.
Leave the electrode in tap water for 15 minutes.
Dip and stir the electrode in concentrated acid (HCI, H
) for 5 minutes.
2S4
Leave the electrode in tap water for 15 minutes.
Dip and stir in strong base (NaOH) for 5 minutes.
Leave the electrode in tap water for 15 minutes.
Test with standard calibration solution.
Finally, test with standard calibration buffer solution to see if the electrode
yields acceptable results. You may repeat again for better response
(maximum 3 times). If the response does not improve, then the electrode has
completed its useful life. Replace with a new electrode.
2.11. Electrode Lifespan
pH electrodes have a finite lifespan due to their inherent properties. How long
a pH electrode will last will depend on how it is cared and the solution it is
used to measure. Even if an electrode is not used it still ages. Electrode
demise can usually be characterized by a sluggish response, erratic readings
or a reading, which will not change. When this occurs an electrode can no
longer be calibrated. pH electrodes are fragile and have a limited lifespan.
Ultrasonic milkanalyser
How long an electrode will last is determined by how well is maintained and
the pH application. The harsher the system, the shorter the lifespan. For this
reason it is always a good idea to have a back-up electrode on hand to avoid
any system down time.
3. Buffer Solutions
Buffers are solutions that have constant pH values and the ability to resist
changes in that pH level. They are used to calibrate pH measurement
system.
PH buffer solution description (Pharmacopoeia standard)
Use only these types’ standard buffers for calibration!
Description pH 7.00±0,01/20ºC pH 4.00±0,01/20ºC
Composition Potassium dihydrogen
phosphate, Di-sodium
Borax, Sodium
hydroxide solution
hydrogen phosphate
Temperature
parameters
10ºC - 7.06
25ºC - 6.99
20ºC - 7.00
30ºC - 6.98
40ºC - 6.95
50ºC - 6.91
10ºC - 4.00
25ºC - 4.00
20ºC - 4.00
30ºC - 4.00
40ºC - 4.00
50ºC - 4.05
4. pH Electrode Calibration
pH Electrodes are like batteries; they run down with time and use. As an
electrode ages, its glass changes resistance. For this reason, electrodes
need to be calibrated on a regular basis. Calibration in pH buffer solution
corrects for this change.
Calibration is an important part of electrode maintenance. This assures not
only that the electrode is behaving properly but that the system is operating
correctly.
Usually pH meters require calibration at 2 specific pH values. One calibration
is usually performed at pH 7, second pH 5.
It is the best to select a buffer as close as possible to the actual pH value of
the sample to be measured. Use standard calibration buffers that the
temperature and the sample solution are the same.
Use the operation manual for the corresponding pH meter.
Ultrasonic milkanalyser
For pH electrodes, originally supplied with milk analyser read the
following information:
Temperature compensations
The output of pH electrodes varies with temperature in manner, predicted by
theory. When needed, Sensorex can supply electrode holders with build-in
automatic temperature compensators. The need of automatic compensation
depends on the temperature variation, the pH value being measured. At pH
of about 7 there is no error due to temperature and, of course, at a constant
temperature there is no error. As shown in the following table, the pH error
due to temperature is a function of both the temperature and the pH value
being measured. At a pH of about 7 there is no error due to temperature and,
of course, at a constant temperature there is no error. The more the
temperature changes from the ambient calibration temperature and the more
the pH departs from 7 the greater is the pH error.
pH temperature error table
°C
pH
2 3 4 5 6 7 8 9 10 11 12
5 .30 .24 .18 .12 .06 0 .06 .12 .18 .24 .30
15 .15 .12 .09 .06 .03 0 .03 .06 .09 .12 .15
25 0 0 0 0 0 0 0 0 0 0
35 .15 .12 .09 .06 .03 0 .03 .06 .09 .12 .15
45 .30 .24 .18 .12 .06 0 .06 .12 .18 .24 .30
55 .45 .36 .27 .18 .09 0 .09 .18 .27 .36 .45
65 .60 .48 .36 .24 .12 0 .12 .24 .36 .48 .60
75 .75 .60 .45 .30 .15 0 .15 .30 .45 .60 .75
85 .90 .72 .54 .36 .18 0 .18 .36 .54 .72 .90
0 pH Error Range Less than .1 pH Error Range
5. PH helpful hints
For greatest accuracy in pH measurement, follow these guidelines:
- Use the same technique to measure samples, which was used for
calibration.
- Be consistent with stirring rates, times and conditions.
- Calibrate with buffers, which are close in temperature to that of the
sample.
- Calibrate the pH electrode regularly, e.g. once a day for accuracy to
within 0.05 pH.
Ultrasonic milkanalyser
- Use fresh buffers for calibrations. Avoid contamination of the stock buffer
solution and do not use it beyond the expiry date.
- Keep all connections dry.
- Immerse the electrode far enough into the solution to insure the
reference junction is below the surface.
- Allow adequate time for the electrode to stabilize in standards and
samples before taking a reading.
- Clean the electrode periodically. Allow more time for aged electrodes.
- Do not use the pH electrode in solutions of fluoride ion at low pH. This
will etch the glass membrane.
- Sulphide vapors can permeate the electrode wick and contaminate the
reference element. Minimize contact in such environments and change
the reference electrolyte frequently.
Milk acidity and рН
In the table below the connection between pH value and acidity in °T is
shown
°T
deviation рН
average
°T
deviation рН
average value
value
Raw milk Pasteurized milk
16 6,74-6,70 6,72 16 6,68-6,64 6,66
17 6,69-6,65 6,68 17 6,63-6,58 6,61
18 6,64-6,58 6,62 18 6,57-6,52 6,55
19 6,57-6,52 6,55 19 6,51-6,46 6,49
20 6,51-6,46 6,49 20 6,45-6,40 6,43
21 6,45-6,40 6,43 21 6,39-6,35 6,37
22 6,39-6,35 6,37 22 6,34-6,30 6,32
23 6,34-6,30 6,32 23 6,29-6,24 6,26
24 6,29-6,24 6,25 24 6,23-6,19 6,21
Ultrasonic milkanalyser
7. PH measuring.
Measuring pH is an additional feature of the analyser and is optional.
Remove the protective rubber cap of the pH electrode. Take care to handle it
appropriate in order not to be damaged. Use de-ionized or distilled water to
rinse the electrode before usage. Fill in the sample holder with milk, put it in
the recess of the analyser and dip the pH electrode into the milk sample,
ensuring complete dip of the electrode in the sample. Stir gently for
homogenization of the sample.
Measuring can be done in two modes:
Off line by starting the menu pH & Co Meter | Measuring, when the
analyser works only as a pH meter.
On line automatic pH measuring, when measuring the rest of the sample’s
parameters.
When starting work with рН meter first connect the probe/sensor, and then
the power supply of the device.
Having in mind the characteristics of the process of pH measuring it is
necessary to dip the рН probe in the sample and then to press the button
Enter.
рН probe is knee-joint (mobile) and is adjusted towards the input pipe of the
analyser.
Move them forward in order to be possible to dip probes’ end in the milk
sample and place the sample holder in the recess of the analyser.
After starting the menu pH & Co Meter the following message appears on
the display:
Ultrasonic milkanalyser
pH Calibration
pH Measuring
pH En/Disable
pH U Display
------------------------pH Test
Co Meter Calibr
Co Meter Test
Co Meter En/Dis
------------------------Exit
8. pH Calibration.
Serves for calibrating the pH meter. For that purpose use 2 standard buffers,
shown on the display as Low buffer (for example 5.00 pH) and High buffer
(for example 7.00 pH). The procedure is following:
1. Start menu Calibration.
2. Put the pH probe in Low buffer.
3. By pressing the buttons of the analyser enter the exact buffer value. The
display shows:
pH Calibr
Put Izopot buff
Buf=xx.xxx
4. Input the buffer value when the probe is in its isopotential point and with
which our probes are accompanied with.
Then the display shows:
pH Calibr
Put Izopot buff
Buf=xx.xxx
V=x.xxxV Set
Where x.xxx is measured by the probe voltage.
Ultrasonic milkanalyser
5. After the readings calm down, the operator has to press the button below
the inscription Set.
6. Repeat the procedure with Next buffer.
The following is displayed:
pH Calibr OK
This means that the procedure for analyser calibration was successfully
completed.
7. pH measuring mode is started automatically.
8. Check calibration correctness by measuring buffer solution 7.00.
9. pH Measuring.
After starting this menu the measurement is done in mode off line, i.e. the
analyser works only as a pH meter. The operator has to dip the probe in the
sample and on the display the following is shown:
pH measuring
x.xxxV
y.yy pH
Exit
Where:
x.xxx – measured by the probe voltage
y.yyy – measured probe’s pH
By pressing the button Exit, the operator may exit the program and to pass
towards another menu.
10. pH En/Disable
Serves for enabling/disabling the pH measuring during normal work of the
analyser - On line. After starting it the display shows:
pH Measuring
XXX
No OK Yes
Ultrasonic milkanalyser
Where XXX is the current situation of the working mode. By pressing the
buttons below the corresponding inscriptions it could be changed, as Yes –
means that during normal work of the analyser – measuring the rest of the
parameters, pH will also be measured. If No is chosen, then pH is not
measured.
11. pH U Display
Serves for allowing/forbidding the value of the pH probe voltage during pH
parameter measuring. After starting it the display shows:
PHUDisplay
XXX
No OK Yes
Where XXX is the current state of the displaying mode. By pressing the
buttons below the inscriptions it could be changed, as Yes – means that
during pH measuring the voltage of the pH probe will be shown.
If No is chosen, it will not be shown. It refers to both of the measuring modes.
12. pH test
serves for testing the measuring system in production mode.
Ultrasonic milkanalyser
APPENDIX 8 CONDUCTIVITY MEASURING (ONLY FOR
DEVICES WITH EMBEDDED FUNCTION)
1. Method of determination.
Conductivity (or Electrolytic Conductivity) is defined as the ability of a
substance to conduct electrical current. It is the reciprocal of the resistance.
In a healthy animal*, the mean value of electric conductivity is:
Milk type Conductivity values
Cow milk between 4 to 6 mS/cm (18°C);
Sheep milk between 3 to 5 mS/cm (18°C);
Buffalo between 2,5 to 5 mS/cm (18°C);
*These values depend on the geographical region, the breed and on other
factors.
Milk conductivity changes on the concentration of ions in the milk:
Added water, sugar,
proteins, insoluble
solids
Added salts Increase the ion's concentration. Milk conductivity
Significantly extreme
value (6,5 - 13,00
mS/cm (18°C)
Decrease the ion's concentration. Milk conductivity
decreases.
increases. Often the milk is falsified by adding salt:
towards milk with good characteristics: fat 4%,
SNF 8,8, conductivity 4,5 are added salt and
water. Then the results are changed to 3,2 and
8,8, conductivity 10. In other words adding water
regulates the increased value of SNF and density
till normal (within the boundaries/parameters) and
even the fat is normal. By the values of these
parameters may be determined if the sample is
falsified, but the only characteristic, proving this is
conductivity, which is out of boundaries
nevertheless added water. But be careful, as the
falsification is not the only possible reason for
conductivity increasing. The other possibility is
mastitis that’s why we recommend using another
(chemical) method for checking it.
Should indicate the development of mastitis.
Infections damage the tissue of the udder. This
allows sodium and chlorine ions from the blood to
Ultrasonic milkanalyser
be released into the milk. The concentration of
ions in the milk is thereby raised, and it can more
easily conduct an electrical current - the
conductivity of the milk increases.
Milk conductivity can be used as tests for degree of water evaporation in
condense milk production.
Milk conductivity change notifies of powder (dry) milk solution rate.
2. Conductivity measurement
Conductivity measurement is additional possibility of the analyser and is
delivered on customers request/
3. Co Meter Calibr
Serves for conductivity measuring system calibration. Clean the analyser
before starting conductivity measurement. (see p. 4.1). You need a standard
buffer with conductivity 5.02[mS/cm] (you may order it for delivery together
o
with the analyser), with temperature 18
С. After starting this mode, the
analyser makes preparation for measurement and when it is ready, the
following message is displayed:
Co Meter Cal
Put 5.02 buff
and press Enter
to start
The operator has to put the buffer and to start the measurement. The
following message appears on the display:
Measurement
started
Wait please
The buffers' temperature is indicated during measurement. After finishing the
measurement the following message appears on the display:
Ultrasonic milkanalyser
Co Pass 1/5=xxxx
Put new sample
and press Enter
to start
Where xxxx is the result from the first calibration measurement. The operator
have to put a new buffer, N.B. do not use one and the same buffer more than
once! Then start the next measurement. This procedure has to be repeated 5
times. At the end the following message appears on the display:
Cond Meter
Calibr= xxxx
Switch Off/On
Now the operator has to switch off the power supply of the analyser. After
switching it on again, the analyser has to be cleaned again with water, which
ends the calibration of the conductivity measurement system calibration.
Note:
Another possibility for calibration of analyzer’s conductivity measurement
function.
You need conductivity meter. First measure milk with normal acidity with
conductivity meter and use it as sample for calibrating the analysers
conductivity measurement function.
4. Co Meter Test.
Serves for testing the working mode of the milk's sample conductivity
measurement system. It is used in the production conditions. After this menu
is chosen, the analyser executes the procedure for sample's measurement
and the display shows the data, used for obtaining the samples conductivity.
Co Meter Test
CoADC= xxxx
Power Off - Stop
5. Co Meter En/Dis.
Enables or disables the conductivity measurement system. The following
message appears on the display:
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