This manual contains instructions for installing and operating the Parr 6400 Calorimeter.
For ease of use, the manual is divided into 13 chapters.
Installation
Quick Start
Operation
Menu Descriptions
Calculations
Reports
Memory Management
Maintenance
Troubleshooting
Technical Service
Parts Lists
Drawings
Tables
Subsections of these chapters are identified in the Table of Contents.
To assure successful installation and operation, the user must study all instructions
carefully before starting to use the calorimeter to obtain an understanding of the
capabilities of the equipment and the safety precautions to be observed in the operation.
Additional instructions concerning the installation and operation of various component
parts and peripheral items used with the 6400 calorimeter should be made a part of
these instructions. Additional instructions for the optional printer are found in the
respective printer package and should be made a part of this book.
No. Description
201M Limited Warranty
207M Analytical Methods for Oxygen Bombs
230M Safety in the Operation of Laboratory and Pressure Vessels
483M Introduction to Bomb Calorimetry
Note:
The unit of heat used in this manual is the International Table (IT) calorie,
which is equal to 4.1868 absolute joules.
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6400 Calorimeter Instruction Manual
Purpose
Heats of combustion, as determined in an oxygen bomb calorimeter such as the 6400
Isoperibol Calorimeter, are measured by a substitution procedure in which the heat
obtained from the sample is compared with the heat obtained from a standardizing
material. In this test, a representative sample is burned in a high-pressure oxygen
atmosphere within a metal pressure vessel or “bomb”. The energy released by the
combustion is absorbed within the calorimeter and the resulting temperature change is
recorded.
Explanation of Symbols
I
O
~
On position
Off position
Alternating Current (AC)
This CAUTION symbol may be present on
the Product Instrumentation and literature.
If present on the product, the user must
consult the appropriate part of the
accompanying product literature for more
information.
Protective Earth (PE) terminal. Provided
for connection of the protective earth
(green or green/yellow) supply system
conductor.
Chassis Ground. Identifies a connection
to the chassis or frame of the equipment
shall be bonded to Protective Earth at the
source of supply in accordance with
national and local electrical code
requirements.
Earth Ground. Functional earth
connection. NOTE: This connection shall
be bonded to Protective earth at the
source of supply in accordance with
national and local electrical code
requirements.
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Safety Information
To avoid electrical shock, always:
1. Use a properly grounded electrical outlet of correct voltage and current handling
capability.
2. Ensure that the equipment is connected to electrical service according to local
national electrical codes. Failure to properly connect may create a fire or shock
hazard.
3. For continued protection against possible hazard, replace fuses with same type
and rating of fuse.
4. Disconnect from the power supply before maintenance or servicing.
To avoid personal injury:
1. Do not use in the presence of flammable or combustible materials; fire or
explosion may result. This device contains components which may ignite such
material.
2. Refer servicing to qualified personnel.
Intended Usage
If the instrument is used in a manner not specified by Parr Instrument Company, the
protection provided by the equipment may be impaired.
Before connecting the calorimeter to an electrical outlet, the user must be certain that
the electrical outlet has an earth ground connection and that the line, load and other
characteristics of the installation do not exceed the following limits:
Voltage: Fluctuations in the line voltage should not exceed 10% of the rated nominal
voltage shown on the data plate.
Frequency: Calorimeters can be operated from either a 50 or 60 Hertz power supply
without affecting their operation or calibration.
Current: The total current drawn should not exceed the rating shown on the data plate
on the calorimeter by more than 10 percent.
Environmental Conditions
Operating: 15ºC to 30ºC; maximum relative humidity of 80% non-condensing.
Installation Category II (overvoltage) in accordance with IEC 664.
Pollution degree 2 in accordance with IEC 664.
Altitude Limit: 2,000 meters.
Storage: -25ºC and 65ºC; 10% to 85% relative humidity.
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6400 Calorimeter Instruction Manual
INSTALLATION
Note:
Some of the following manual sections contain information in the form of
warnings, cautions and notes that require special attention. Read and
follow these instructions carefully to avoid personal injury and damage to
the instrument. Only personnel qualified to do so, should conduct the
installation tasks described in this portion of the manual.
Each Parr 6400 Calorimeter was completely assembled and thoroughly tested prior to
shipment. Unpack the calorimeter and carefully check the individual parts against the
packing list. If shipping damage is discovered, save the packing cartons and report it
immediately to the delivering carrier.
This apparatus is to be used indoors. It requires at least 4 square feet of workspace on a
sturdy bench or table in a well-ventilated area with convenient access to an electric
outlet, running water and a drain. The supply voltage must be within ± 10% of marked
nominal voltage on the apparatus. The supply voltage receptacle must have an earth
ground connection.
When Swagelok Tube Fittings are used, the instructions for installation are:
1. Simply insert the tubing into the Swagelok Tube Fitting. Make sure that the
tubing rests firmly on the shoulder of the fitting and that the nut is fingertight.
2. Before tightening the Swagelok nut, scribe the nut at the 6 o’clock position.
3. While holding the fitting body steady with a back-up wrench, tighten the nut
1-1/4 turns. Watch the scribe mark, make one complete revolution and
continue to the 9 o’clock position.
4. For 3/16" and 4mm or smaller tube fittings, tighten the Swagelok nut 3/4 turns
from finger-tight.
Swagelok tubing connections can be disconnected and retightened many times. The
same reliable leak-proof seal can be obtained every time the connection is remade using
the simple two-step procedure.
1. Insert the tubing with pre-swaged ferrules into the fitting body until the front
ferrule seats.
2. Tighten the nut by hand. Rotate the nut to the original position with a wrench.
An increase in resistance will be encountered at the original position. Then
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6400 Calorimeter Instruction Manual
tighten slightly with a wrench. Smaller tube sizes (up to 3/16” or 4mm) take less
tightening to reach the original position than larger tube sizes.
The type of tubing and the wall thickness also has an effect on the amount of tightening
required. Plastic tubing requires a minimal amount of additional tightening while heavy
wall metal tubing may require somewhat more tightening. In general, the nut only needs
to be tightened about 1/8 turn beyond finger tight where the ferrule seats in order to
obtain a tight seal.
Over tightening the nut causes distortion (flaring) of the lip of the tube fitting where the
ferrule seats. This in turn causes the threaded portion of the body to deform. It
becomes difficult to tighten the nut by hand during a subsequent re-tightening when the
fitting body becomes distorted in this manner.
Consumables, Utilities and Power Requirements
The 6400 Calorimeter requires availability of oxygen, 99.5% purity, with CGA 540
connection, 2500 psig, maximum.
The 6400 Calorimeter requires availability of nitrogen or air, oil and water free, with CGA
580 connection, 2500 psig, maximum.
Approximately 16L of distilled water are required to fill the external pressurized rinse
tank.
Approximately 2L of tap water, with a total hardness of 85 ppm or less, are required for
filling the internal cooling reservoir.
The power requirements for the sub-assemblies of the 6400 Calorimeter are:
Calorimeter
5A @ 120 VAC
3A @ 230 VAC
Printer
(100 to 240 VAC, 50/60 Hz) 0.35 A
Electrical Connection
Plug the power line into any grounded outlet providing proper voltage that matches the
specification on the nameplate of the calorimeter. Grounding is very important not only
as a safety measure, but also to ensure satisfactory controller performance. If there is
any question about the reliability of the ground connection through the power cord, run a
separate earth ground wire to the controller chassis.
Turn the power switch to the ON position. After a short time, the Parr logo will appear on
the LCD display followed by a running description of the instrument boot sequence.
When the boot sequence is complete, the Main Menu is displayed.
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6400 Calorimeter Instruction Manual
Figure 1 - 6400 Calorimeter Back Panel - Label
Water Connection
Remove the cap plug on the water filling elbow and fill the internal reservoir tank with
water having a total hardness of 85 ppm or less, until the water level is at the bottom of
the filling elbow. The calorimeter water tank will initially accept about 2 liters.
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6400 Calorimeter Instruction Manual
Fill the external rinse tank with about 16 liters of distilled water through the large opening
at the top of the tank. The cover for this opening is removed by lifting up on the handle,
pushing down on the lid, tilting and removing. Replace and close the cover after filling.
The two connections between the calorimeter and the 1576 Rinse Tank should be made
with two pieces of 1/8” nylon pressure hose (HX0012TB024).
Figure 2 - 6400 External Plumbing
Gas Connection
Make the connections to the oxygen supply at this time. Refer to Figure 2. 1/8” O.D.
nylon pressure hose (HX0012TB024) is used to connect the oxygen supply. The inlet
connection incorporates a flow restrictor just behind the inlet connection. When making
the oxygen connection, a back-up wrench should be placed on the restrictor to insure a
secure connection and to prevent over tightening the flow restrictor. The delivery
pressure for oxygen should be set to 450 psig. To install the regulator, unscrew the
protecting cap from the tank and inspect the threads on the tank outlet to be sure they
are clean and in good condition. Place the ball end of the regulator in the tank outlet and
draw up the union nut tightly, keeping the gages tilted slightly back from an upright
position. Open the tank valve and check for leaks. The bomb must never be filled to
more than 600 psig (40 atm).
Make the connections to the nitrogen supply at this time. Refer to Figure 2. 1/4” O.D.
nylon pressure hose (HJ0025TB035) is used to connect the nitrogen supply. When
making the nitrogen connection, a back-up wrench should be placed on the restrictor to
insure a secure connection and to prevent over tightening the flow restrictor. The
delivery pressure for nitrogen should be set at 80 psig. To install the regulator, unscrew
the protecting cap from the tank and inspect the threads on the tank outlet to be sure
they are clean and in good condition. Place the ball end of the regulator in the tank
outlet and draw up the union nut tightly, keeping the gages tilted slightly back from an
upright position. Open the tank valve and check for leaks.
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6400 Calorimeter Instruction Manual
Note:
A hissing sound will occur while the rinse tank is being pressurized. This
is normal. Adjust the pneumatic supply regulator to 80 psig as needed.
During extended periods of inactivity, close the tank valve to prevent depleting the tank
in the event of a leak. Close the tank valve prior to removing the regulator when
changing tanks. Do not use oil or combustible lubricants in connection with any part of
the oxygen filling system. Keep all threads, fittings and gaskets clean and in good
condition.
Bomb Exhaust Connections
The exhaust and vent connections at the rear of the calorimeter, are made with the dual
tube A1006DD assembly. The end of the assembly with the bomb exhaust diffuser
should be placed into the 10 liter carboy (231C2). The carboy should be placed at or
below the level of the calorimeter to facilitate complete draining of these lines.
Alternatively:
The A1050DD Bomb Rinse Container Assembly is provided as an accessory to the 6400
Calorimeter. See Figure 28. This device allows for complete and systematic recovery of
the bomb combustion products. These combustion products include the initial line
exhaust after the fill cycle and the portion expelled during the bomb rinse cycle. The
Bomb Rinse Container Assembly is connected to the rear of the calorimeter, in place of
the portion of the waste tube assembly that is connected to the bomb exhaust fitting.
Combustion products are discharged from the bomb in two steps. The first step occurs
during the initial rapid release of the residual bomb gases. The 1053DD bottle has
sufficient strength and volume to deal effectively with this sudden pressure release. Gas
is expelled from the four holes on the perimeter of the 1052DD bottle cap, leaving any
discharged liquid in the bottle. As an additional safety measure, the bottle is supported
in a 1054DD acrylic cylinder which serves to keep the bottle upright and contained in the
unlikely event the bottle ruptures. At the end of the bomb exhaust step the aqueous
combustion products reside in the bomb, associated tubing as well as the 1053DD
bottle. The bomb rinse step flushes these combustion products from the bomb and the
tubing into the 1053DD bottle. The bottle can then be unscrewed from the assembly and
capped, until the sample is to be analyzed. Some users find it useful to add the contents
of the rinsed combustion capsule to the washings collected in the bottle. Three 1053DD
bottles are provided with the assembly. Additional bottles may be ordered separately
from Parr.
Communication Connections
There are three RS-232 serial ports at the rear of the calorimeter. These ports are
designated Terminal, Printer and Balance. The pin-out of these three ports are identical
and can be found in Table 1.
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6400 Calorimeter Instruction Manual
Table 1 - 6400 Calorimeter Serial Ports Pin-Out
9 pin D Connector Pin # Description Direction
(6400 – External Device)
2 Received Data
3 Transmitted Data
4
5 Signal Ground
6
7 Ready to Send (RTS)
8 Clear to Send (CTS)
The RS232 balance port is a female port whereas the RS232 printer port is a male port.
The 6400 Calorimeter is also equipped with an RJ45 Ethernet port for connection to a
computer. Before making any of these connections, the data transmission rate of the
Calorimeter and the printer, balance or computer must be matched. Generally the baud
rates on either device can be changed to achieve this match.
The 6400 will also allow the user to specify the IP addresses of one or more Balance
Interface devices on the network by selecting the Network Data Device menu in the
Communications Controls menu. Balance Interface devices are polled from device 1 to
15 for sample and / or spike weights when the weight entry mode is set to Network.
Figure 3 - 6400 Calorimeter Peripherals
Í
Î
Í Î
Î
Í
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6400 Calorimeter Instruction Manual
Multiple Alternate Configurations
Printer Connections
The printer port settings are on the Communication Controls Menu: Printer Port
Communications Menu. The default parameters for the 6400 are set up for use with the
Parr 1757 Printer. Table 1 identifies and describes the pin-out for the RS-232 port.
Balance Connections
The 6400 Calorimeter supports input from the multiple balance types. Additionally, a
generic input driver is provided for communications with balances that do not conform to
the eight supported protocols. A new feature supported by all balance input drivers is the
ability to change the expected number of characters in the data field. The number of data
characters indicated for each of the drivers, below, are default values. This feature virtually
eliminates the need for balance input drivers to be re-written in the event the balance
manufacturer elects to alter the output string of a balance when new models are
introduced.
The format of an unknown balance can be determined by logging the balance output to
the printer attached to the calorimeter. Those protocols which send a command string to
the balance will do so while logging is active. In order for the logging to produce
meaningful results, the cable connecting the balance to the balance input port of the
calorimeter must be correctly wired or configured. In addition, the specifics of the data
frame, such as the baud rate, # of data bits, parity, # of stop bits and handshaking (if
used) must be the same for both the balance and the calorimeter.
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Mettler 011/012 Interface
The ID field must contain “S_” to
indicate a stable mass. The data field
contains the current mass, right
justified, with a decimal point. The
balance should be configured to send
continuously.
Sartorious Interface
The polarity field must contain either a
“+” or a space. Leading zeros in the
data field are blanked, except for the
one to the left of the decimal point.
The stability field must contain “g_” for
the calorimeter to accept a mass. The
balance should be configured to
transmit data upon receipt of the
following command string:
[ESC] P [CR] [LF]
Note:
The automatic data output option should not be used.
6400 Calorimeter Instruction Manual
Field Length
ID 2
space 1
data 9
space 1
g 1
CR 1
LF 1
Field Length
polarity 1
space 1
data 8
space 1
stability 2
CR 1
LF 1
Generic Interface
The data field should consist of 9
numeric characters (0 through 9, +, and space) terminated with a carriage
return (CR). Leading zeros may be blanked as spaces and are counted.
Non-numeric characters are ignored and will reset the input buffer if the data
field has not been filled. Any characters received after filling the data field
and before the carriage return are ignored.
Field Length
data 8
CR 1
Bar Code Port
The use of barcodes in the laboratory has become a highly accurate, rapid and
inexpensive way to identify samples. When purchasing this feature, the user must
supply Parr with the MAC address of the calorimeter (found in the Software & Hardware
Info menu screen). This allows Parr to activate the feature key. In order to enable the
calorimeter to use the bar code feature, the feature key needs to be entered into the
instrument. Select the “Program Information and Control” key from the Main Menu.
Next, select “Feature Key” and enter the feature key purchased from Parr Instrument
Company into the instrument by using the touchpad. Pressing the key labeled “ABC”
allows the user to switch from upper case letters, to lower case letters, to numerals, and
finally to symbols. A CD containing all the necessary documentation and setup
information for using both the scanner and the printer is provided at the time of
purchase. A PC based program used for printing bar coded labels is also provided on
this CD.
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6400 Calorimeter Instruction Manual
Computer Connections
If the 6400 Calorimeter is to be
connected to a computer, the Ethernet
connection should be used. Test data
can be transferred to an Ethernet
network connected computer using the
FTP File Transfer Protocol. First, you
must know the IP address of the
network-connected calorimeter. The
network DHCP (Dynamic Host
Configuration Protocol) server
provides this address shortly after the
calorimeter is turned on. The address
can be seen on the Software &
Hardware Info” screen, under Program
Info and Control Menu (see the example screenshot). Users who don’t have a network
infrastructure can create a simple network by connecting a router with DHCP server
capability to the calorimeter using an ordinary CAT 5 network cable. The calorimeter
should be connected to LAN side of the router. The PC in turn is also connected to the
LAN side of the router using a similar CAT 5 cable. A D-Link 614+ router is
recommended for this purpose. For this router, operated without a WAN connection, the
primary DNS address of the router (WAN setup) must be set to the IP address of the
router found on the LAN setup page. Other routers behave differently in the absence of
a WAN connection. Providing an active upstream connection to the WAN port of most
routers generally minimizes the use of any obscure setup configurations. An FTP
enabled web browser can be used to access stored test data. The URL is of the
following form:
ftp://root:rootroot@192.168.0.125/../flash/data/
In this case, 192.168.0.125 is the IP address of the calorimeter.
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6400 Calorimeter Instruction Manual
The following screenshot illustrates the contents of the calorimeter data directory as
presented by a web browser.
You can drag and drop or copy and paste test data files (with the csv suffix) from the
web browser window to any convenient folder or directory on the PC.
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6400 Calorimeter Instruction Manual
The calorimeter offers a web server service. Test reports can be viewed with a web
browser using a URL of the following form: http://192.168.0.125
the IP address of the calorimeter.
Clicking on the Sample Data tab displays a list of reports currently in the instrument
memory.
, where 192.168.0.125 is
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6400 Calorimeter Instruction Manual
Clicking on any given report will provide a display similar to the following:
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6400 Calorimeter Instruction Manual
QUICK START
1. Turn on the heater and pump in the Calorimeter Operation menu. Allow at least 20
minutes for the calorimeter to warm up.
2. Initiate a pretest to run the calorimeter through the fill and cool/rinse cycles. This
function is used to pre-condition the calorimeter if it has been sitting idle for an extended
period of time (greater than 15 minutes).
3. Prepare and weigh the sample to 0.0001g.
4. Gently tap capsules that contain powdered samples to compact the material. (Pellets
are easier to handle than loose samples and they burn slower in the bomb, thereby
reducing the chances for incomplete combustion).
5. Carefully place the capsule into the capsule holder, attach 10 cm of ignition thread and
install the bomb head in the calorimeter.
6. Close the calorimeter cover making sure that the latch is engaged.
7. Select determination or standardization as appropriate on the Calorimeter Operation
page, by toggling the operating mode key. Press the Start Key. The calorimeter will
now prompt the operator for Bomb ID number, sample ID number, sample weight and
spike weight in accordance with the instructions set into the operating controls page.
8. The calorimeter will now take over and conduct the test. During the time it is establishing
the initial equilibrium, it will display PREPERIOD on the status bar. Just before it fires
the bomb, it will sound a series of short beeps to warn the user to move away from the
calorimeter. Once the bomb has been fired, the status bar will display POSTPERIOD.
The calorimeter will check to make certain that a temperature rise occurs and will then
look for the final equilibrium conditions to be met. If it fails to meet either the initial or
final equilibrium conditions, or if it fails to detect a temperature rise within the allotted
time, the test will terminate and advise the user of the error.
9. At the conclusion of the test, the calorimeter will signal the user.
10.
Open the cover and remove the head. Examine the interior of the bomb for soot or other
evidence of incomplete combustion. If such evidence is found, the test will have to be
discarded.
11. Titrate the bomb washings with a standard sodium carbonate solution using methyl
orange, red or purple indicator. A 0.0709N sodium carbonate solution is recommended
for this titration to simplify the calculation. This is prepared by dissolving 3.76 grams of
Na
2CO3
normality may be used.
12. Analyze the bomb washings to determine the sulfur content of the sample if it exceeds
0.1%. Methods for determining sulfur are discussed in Analytical Methods for Oxygen
Bombs, No. 207M.
in the water and diluting to one liter. NaOH or KOH solutions of the same
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6400 Calorimeter Instruction Manual
OPERATION
Menu System
All configurations and operations are
handled by a menu-driven system
operated from the bright touch screen
display. The settings and controls are
organized into ten main sections as
displayed on the MAIN MENU.
Note:
Keys with a “double box” in the
upper left hand corner lead to
sub-menus.
Menu Keys
The controls that change the data field information in the menus will be one of the
following:
1. Toggles. These data fields contain ON/OFF or YES/NO choices. Simply touching
the key on the screen toggles the choice to the other option. The current setting is
displayed in the lower right corner of the key.
2. Option Selection. These data fields contain a list of options. Touching the key on
the screen steps the user through the available choices. The current setting is
displayed in the lower right corner of the key.
3. Value Entry Fields. These data fields are used to enter data into the Calorimeter.
Touching the key on the screen brings up a sub-menu with a key pad or similar
screen for entering the required value.
clear the current value before entering a new value. Once entered the screen will
return to the previous menu and the new value will be displayed in the lower right
corner of the key.
4. Data Displays. Most of these keys display values that have been calculated by the
calorimeter and are informational only. Certain ones can be overridden by the user
entering a desired value through a sub-menu. The value is displayed in the lower
right corner of the key.
Note:
Some keys will respond with an opportunity for the user to confirm the
specified action to minimize accidental disruptions to the program and/or
stored data.
Some keys lead to multiple choices. Always
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6400 Calorimeter Instruction Manual
Control Keys
There are five control keys which always appear in the right column of the primary
displays. These keys are unavailable when they are gray instead of white.
1. Escape. This key is used to go up one level in the menu structure.
2. Main Menu. This key is used to return to the main menu touch screen from
anywhere in the menu structure.
3. Start. This key is used to start a test.
4. Report. This key is used to access the test results stored in the calorimeter, to enter
thermochemical corrections, and to initiate a report on the display, printer or attached
computer.
5. Help. This key is used to access help screens related to the menu currently
displayed on the touch screen.
Programming
The program in the 6400 Calorimeter can be extensively modified to tailor the unit to a
wide variety of operating conditions, reporting units, laboratory techniques, available
accessories and communication modes. In addition, the calculations, thermochemical
corrections and reporting modes can be modified to conform to a number of standard
test methods and procedures. Numerous provisions are included to permit the use of
other reagent concentrations, techniques, combustion aids and short cuts appropriate for
the user’s work.
Note:
Changes to the program are made by use of the menu structure. Any of
these items can be individually entered at any time to revise the operating
program.
Default Settings
Units are preprogrammed with default settings. See Table 2 for a listing of the factory
default settings. A more in-depth explanation of these parameters is found on the
corresponding parameter group help pages. These default settings remain in effect until
changed by the user. Should the user ever wish to return to the factory default settings,
go to the Program Info and Control Menu, User/Factory Settings, touch Reload Factory
Default Settings and YES. Non-volatile memory is provided to retain any and all
operator initiated program changes; even if power is interrupted or the unit is turned off.
If the unit experiences an intentional or unintentional “Cold Restart”, the controller will
return to the last known settings.
The default parameters of the 6400 calorimeter can be changed to guarantee that the
calorimeter, when cold restarted, will always be in the desired configuration before
beginning a series of tests. Users who wish to permanently revise their default settings
may do so using the following procedure:
• Establish the operating parameters to be stored as the user default settings.
• Go to the Program Info and Control Menu, User/ Factory Settings, User Setup ID,
and enter the desired User Setup ID.
• Select Save User Default Settings
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6400 Calorimeter Instruction Manual
To re-load the user default setting, go to the Program Info and Control Page,
User/Factory Settings, Re-load User Default Settings, and YES.
Sample Preparation
Sample Size
To stay within safe limits, the bomb should never be charged with a sample which will
release more than 8000 calories when burned in oxygen. The initial oxygen pressure is
set at 30 atmospheres (450 psig). This generally limits the mass of the combustible
charge (sample plus benzoic acid, gelatin, firing oil or any combustion aid) to not more
than 1.1 grams. To avoid damage to the bomb and calorimeter, and possible injury to
the operator, it should be a standing rule in each laboratory that the bomb must never be
charged with more than 1.5 grams of combustible material.
When starting tests with new or unfamiliar materials, it is always best to use samples of
less than 0.7 grams with the possibility of increasing the amount if preliminary tests
indicate no abnormal behavior and sample will not exceed the 8000 calorie limit.
Samples containing sulfur should contain no more than 50 mg of sulfur and have a
calorific value of at least 9000 BTU/lb.
Samples containing chlorine should be spiked to insure that sample contains no more
than 100 mg of chlorine and liberates at least 5000 calories
Particle Size and Moisture Content
Solid samples burn best in an oxygen bomb when reduced to 60 mesh, or smaller, and
compressed into a pellet with a 2811 Parr Pellet Press. Large particles may not burn
completely and small particles are easily swept out of the capsule by turbulent gases
during rapid combustion.
Note:
Particle size is important because it influences the reaction rate.
Compression into a pellet is recommended because the pressure
developed during combustion can be reduced as much as 40% when
compared to the combustion of the material in the powder form. In
addition to giving controlled burn rates, the formation of pellets from
sample material keeps the sample in the fuel capsule during combustion.
Materials, such as coal, burn well in the as-received or air-dry condition, but do not burn
completely dry samples. A certain amount of moisture is desirable in order to control the
burning rate. Moisture content up to 20% can be tolerated in many cases, but the
optimum moisture is best determined by trial combustions. If moisture is to be added to
retard the combustion rate, drop the water directly onto the loose sample or onto a pellet
after the sample has been weighed. Then let the sample stand to obtain uniform
distribution. Low volatile samples with high water content, such as urine or blood, can
be burned in an open capsule by absorbing the liquid on filter paper pulp or by adding a
combustion aid, such as ethylene glycol.
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6400 Calorimeter Instruction Manual
Sample Types
Because of the difference in combustion characteristics of the many different materials
which may be burned in an oxygen bomb, it is difficult to give specific directions which
will assure complete combustions for all samples.
The following fundamental conditions should be considered when burning samples:
•Some part of the sample must be heated to its ignition temperature to start the
combustion and, in burning, it must liberate sufficient heat to support its own
combustion regardless of the chilling effect of the adjacent metal parts.
•The combustion must produce sufficient turbulence within the bomb to bring
oxygen into the fuel cup for burning the last traces of the sample.
•A loose or powdery condition of the sample which will permit unburned particles
to be ejected during a violent combustion.
•The use of a sample which contains coarse particles will not burn readily. Coal
particles which are too large to pass a 60 mesh screen may not burn completely.
•The use of a sample pellet which has been made too hard or too soft can cause
spalling and the ejection of unburned fragments.
•The bottom of the cup should always be at least one-half inch above the bottom
of the bomb or above the liquid level in the bomb to prevent thermal quenching.
•If the moisture, ash and other non combustible material in the sample totals
approximately 20% or more of the charge, it may be difficult to obtain complete
combustion. This condition can be remedied by adding a small amount of
benzoic acid or other combustion aid.
Foodstuffs and Cellulosic Materials
Fibrous and fluffy materials generally require one of three modes for controlling the burn
rate. Fibrous materials do not pelletize readily and generally require either moisture
content or a combustion aid such as mineral oil to retard the burn rate and avoid
development of high pressures. Partial drying may be necessary if the moisture content
is too high to obtain ignition, but if the sample is heat sensitive and cannot be dried, a
water soluble combustion aid such as ethylene glycol can be added to promote ignition.
Material such as Napthalene should not be burned in loose powder form but should be
formed into a pellet.
Coarse Samples
In most cases it may be necessary to burn coarse samples without size reduction since
grinding or drying may introduce unwanted changes. There is no objection to this if the
coarse sample will ignite and burn completely. Whole wheat grains and coarse charcoal
chunks are typical of materials which will burn satisfactorily without grinding and without
additives or a special procedure.
Corrosive Samples
The 1138 bomb is made from alloy 20; a special niobium stabilized stainless steel
selected for its resistance to the mixed nitric and sulfuric acids produced during the
combustion process. The 1138CL is made from the halogen resistant Hastelloy G30™.
Hastelloy 30™ is an alloy rich in cobalt and molybdenum and is able to resist the
corrosive effects of free chlorine and halogen acids produced when burning samples
with significant chlorine content. While no alloy will completely resist the corrosive
atmospheres produced when burning samples containing halogen compounds; users
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6400 Calorimeter Instruction Manual
who intend to test these materials are urged to select the 1138CL Bomb. These bombs
are 250 mL in volume and are rated to a maximum working pressure of
bombs are hydrostatically tested to 3000 psi and the sample range is ~1g or 5000 – 8000
calories.
Explosives and High Energy Fuels
Materials which release large volumes of gas which detonate with explosive force or
burn with unusually high energy levels, should not be tested in this calorimeter. Rather,
they should be tested in a model 6100 or 6200 Calorimeter which can be equipped with
an 1104 High Strength Oxygen Bomb designed specifically for these types of samples.
Volatile Sample Holders
Volatile samples are defined as one with an initial boiling point below 180ºC per ASTM
D-2. Volatile samples can be handled in a Parr 43AS Alloy Capsule which has a sturdy
wall with a flat top rim. These holders can be sealed with a disc of plastic adhesive tape
prepared by stretching tape across the top of the cup and trimming the excess with a
sharp knife. The seal obtained after pressing this disc firmly against the rim of the cup
with a flat blade will be adequate for most volatile samples. The tape used for this
purpose should be free of chlorine and as low in sulfur as possible. Borden Mystic Tape,
No. M-169-C or 3M Transparent Tape, No. 610, are recommended for this purpose. The
3M Transparent Tape can be ordered through Parr, Part No. 517A.
Figure 4 - Volatile Sample Technique
The weight of the tape disc must be
determined separately and a correction
applied for any elements in the tape
which might interfere with the
determination. The approximate Heat of
Combustion of the tape is 6300 cal/g. An
actual amount should be determined by
running a blank test with tape alone using
a sample weighing 1.0 gram. The
compensation for heat of tape may be
done through the spike option; see Spike
Controls, Heat of Combustion of Spike.
Note:
Tape should always be stored in a sealed container to minimize changes in
its moisture and solvent content.
Use the following procedure when filling and handling any of these tape-sealed sample
holders:
1. Weigh the empty cup or capsule; then cover the top with tape, trim with a knife
and press the trimmed edge firmly against the metal rim. Also cut and attach a
small flag to the disc (see Figure 4).
2. Puncture the tape at a point below the flag, then re-weigh the empty cup with its
tape cover.
3. Add the sample with a hypodermic syringe; close the opening with the flag and
re-weigh the filled cup.
2000 psi. The
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6400 Calorimeter Instruction Manual
4. Set the cup in the capsule holder and arrange the auxiliary fuse so that it touches
the center of the tape disc.
5. Just before starting the test, prick the disc with a sharp needle to make a small
opening which is needed to prevent collapse of the disc when pressure is
applied.
6. Fill the bomb with the usual oxygen charging pressure.
7. The calorimeter will fire the bomb and complete the test in the usual manner.
Combustion Aids
Some samples may be difficult to ignite or they may burn so slowly that the particles
become chilled below the ignition point before complete combustion is obtained. In such
cases white oil or other suitable material of known purity can be mixed with the sample.
Ethylene glycol, butyl alcohol or decalin may be used for this purpose.
Note:
It must be remembered, that a combustion aid adds to the total energy
released in the bomb and the amount of sample may have to be reduced
to compensate for the added charge.
When benzoic acid is combusted for standardization runs, it should be in the form of a
pellet to avoid possible damage to the bomb which might result from rapid combustion of
the loose powder.
Combustion Capsules
Non-volatile samples to be tested in Parr oxygen bombs are weighed and burned in
shallow capsules measuring approximately 1" diameter and 7/16" deep. These are
available in stainless steel, fused silica and platinum alloyed with 3-1/2% rhodium.
Stainless steel capsules (43AS) are furnished with each calorimeter. The stainless steel
capsules will acquire a dull gray finish after repeated use in an oxygen bomb due to the
formation of a hard, protective oxide film. This dull finish not only protects the capsule,
but it also promotes combustion and makes it easier to burn the last traces of the
sample. New capsules are heated in a muffle furnace at 500ºC for 24 hours to develop
this protective coating uniformly on all surfaces. This treatment should be repeated after
a capsule has been polished with an abrasive to remove any ash or other surface
deposits. Heating in a muffle is also a good way to destroy any traces of carbon or
combustible matter which might remain in the capsule from a previous test. Capsules
should be monitored for wear. Do not use the capsule if the wall or base thickness is
less than 0.025”.
Note:
After heating, place the capsules in a clean container and handle them
only with forceps when they are removed to be weighed on an analytical
balance.
When combusting samples that contain metal particles such as aluminum or
magnesium, the non-metallic (fused silica) 43A3 Capsule is required.
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6400 Calorimeter Instruction Manual
When superior corrosion resistance is needed, the Platinum Rhodium 43A5 Capsule is
required.
Test Process
Loading the sample
Prepare and weigh the sample to 0.0001g. Gently tap capsules that contain powdered
samples to compact the material. (Pellets are easier to handle than loose samples and
they burn slower in the bomb, thereby reducing the chances for incomplete combustion).
Carefully place the capsule into the capsule holder. A cotton thread (845DD2) is used
as an auxiliary fuse to ignite the sample. Remove any moisture from the heating wire
prior to attaching the cotton thread.
Figure 5 - Cotton Thread Assembly
Four inches of thread is recommended for this auxiliary thread which is looped over the
heating wire, doubled on itself, twisted to form a single strand and fed into the sample
cup to lay on the sample. When contact is made through the heating wire, the thread
will ignite, drop into the sample cup and ignite the sample. One spool of thread, part
number 845DD, is 563 yards. Part number 845DD2 contains approximately 1000 pieces
of thread pre-cut to 4 inches.
Closing the bomb
Care must be taken not to disturb the sample when moving the bomb head from the
support stand to the bomb cylinder in the calorimeter. Check the sealing ring to be sure
that it is in good condition and moisten it with a bit of water so that it will slide freely into
the cylinder.
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6400 Calorimeter Instruction Manual
Notice that the bomb head grounding lug extends beyond the outside diameter of the
bomb head. A slot for this lug is cut into the top of the calorimeter bucket which holds
the bomb cylinder. Position this lug approximately 20 degrees to the operators right and
slide the head into the cylinder and push it down as far as it will go. Now rotate the
bomb head 20 degrees to the left until the lug contacts the left edge of the cut out and is
pointed to the front of the calorimeter.
Fill Cycle
Once the calorimeter is started and the cover is closed, the fill sequence begins.
Figure 6 - Bucket Fill Flow Diagram
1. The calorimeter checks the bomb ignition circuitry for continuity.
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6400 Calorimeter Instruction Manual
2. The water fill solenoid opens and water is pumped from the internal tank into and
through the bucket that surrounds the bomb. Overflow from the bucket is
returned to the closed water tank. Because the jacket and bucket are both filled
with water from the closed water tank, initial equilibrium will be reached quickly.
3. The oxygen fill solenoid is opened and oxygen is added slowly to the bomb to
bring its pressure to approximately 30 atm.
Pre-Period
At the completion of the fill sequence, the pre-period begins.
Figure 7 - Pre-Period / Post-Period Flow Diagram
1. The water fill solenoid valve closes and isolates the water in the bucket from the
rest of the system. Water within this bucket is circulated by the stirrer. Water
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6400 Calorimeter Instruction Manual
continues to circulate from the closed water system through the jacket
surrounding the bucket.
2. The oxygen filling valve closes and the pressure in the filling line is vented. The
automatic check valve at the top of the bomb closes and isolates the bomb from
the oxygen filling line.
3. The controller monitors the operating temperature until it confirms that the initial
equilibrium has been established.
Bomb Firing
Once the initial equilibrium is confirmed, the controller initiates the firing sequence.
There are no changes to the circulation pattern, as shown in Figure 7, from the preperiod through the bomb firing and post-period. A warning of short beeps is sounded
indicating the bomb is about to be fired.
Post-Period
A minimal temperature rise will confirm that the sample has ignited. After this verification,
the post-period begins. See Figure 7.
1. The controller monitors the temperature rise and determines the final temperature
2. Once the final temperature rise is determined, it is recorded with the test results.
rise by either the dynamic or equilibrium criteria as established by the user.
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6400 Calorimeter Instruction Manual
Cool / Rinse
At the completion of the post-period, the rinse and cool sequence begins.
Figure 8 - Rinse & Cool Flow Diagram
1. Chilled water is circulated through the bucket to cool the bomb to the starting
temperature.
2. The release valve in the bottom of the bomb is opened and the residual pressure is
released through the bomb exhaust line.
3. Once the excess oxygen is vented, the bomb rinse water from the rinse water tank is
admitted through the bomb rinse solenoid valve and the check valve at the top of the
bomb. The bomb rinse water is released to the wash bottle.
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