KERN ACS-A03 Operating Instructions Manual
KERN & Sohn GmbH
Ziegelei 1
D-72336 Balingen
E-Mail: info@kern-sohn.com
Phone: +49-[0]7433- 9933-0
Fax: +49-[0]7433-9933-149
Internet: www.kern-sohn.com
Operating instructions
Set for Density determination for
Analytical Balances KERN ACJ / ACS
KERN ACS-A03
Version 1.0
04/2012
GB
ACS-A03-BA-e-1210
2 ACS-A03-BA-e-1210
GB
KERN ACS-A03
Version 1.0 04/2012
Operating instructions
Density Determination Set for Analytical Balances
KERN ACJ / ACS
Contents:
1 INTRODUCTION ................................................................................................................................. 3
1.1 SCOPE OF DELIVERY .................................................................................................................. 3
2 PRINCIPLE OF DENSITY DETERMINATION ................................................................................... 5
2.1 INFLUENCING MAGNITUDES AND ERROR SOURCES ....................................................................... 6
3 INSTALLING THE DENSITY DETERMINATION SET ....................................................................... 7
4 DENSITY DETERMINATION OF SOLIDS ......................................................................................... 9
4.1 ACTIVATE "DENSITY DETERMINATION SOLID MATTER" MODE ......................................................... 9
4.2 CALCULATE DENSITY ...............................................................................................................11
4.3 DENSITY DETERMINATION OF SOLID MATERIAL WITH A DENSITY OF LESS THAN 1 G/CM3 ................12
5 DETERMINING DENSITY OF LIQUIDS ...........................................................................................13
5.1 DETERMINE VOLUME OF THE GLASS SINKER ..............................................................................13
5.2 CALL UP "DENSITY DETERMINATION FLUID" ................................................................................14
5.3 CALCULATE DENSITY ...............................................................................................................15
6 DATA-HOLD FUNCTION .................................................................................................................16
6.1 ACTIVATE FUNCTION ................................................................................................................16
6.2 HOLD / DELETE RESULT OF DENSITY DETERMINATION ON DISPLAY...............................................16
7 PRECONDITIONS FOR PRECISE MEASUREMENTS ................................................................17
7.1 CALCULATION OF RESULTS ......................................................................................................17
7.2 INFLUENCE FACTORS FOR MEASUREMENT ERRORS ..................................................................17
7.2.1 Air bubbles ........................................................................................................................17
7.2.2 Solid matter sample ..........................................................................................................17
7.2.3 Liquids ...............................................................................................................................18
7.2.4 Surface ..............................................................................................................................18
7.3 GENERAL INFORMATION ...........................................................................................................18
7.3.1 Density / Relative Density .................................................................................................18
7.3.2 Drift of Balance Display ....................................................................................................18
8 DENSITY TABLE FOR FLUIDS ....................................................................................................19
9 MEASUREMENT UNCERTAINTY DURING DENSITY DETERMINATION OF SOLID MATTER20
10 USER INSTRUCTIONS .................................................................................................................21
ACS-A03-BA-e-1210 3
1 Introduction
• In order to guarantee a safe and trouble-free operati on, pl ease
read carefully the operating instructions.
• These operating instructions only describe the operation of the
density determination s et. For further information on how to
operate your balance please refer to the operating instructions
supplied with each balance.
1.1 Scope of delivery
Check packaging and density determination set immediately when unpacking for
possible visible dam age.
Make sure that all parts are completely present.
Fig. 1 Scope of delivery
No. Description Number
(1) -1 Immer sion basket for descending solid matter (density > 1 g/cm³) 1
(1) -2 Immer sion basket for floati ng solid matter ( density < 1 g/cm³) 1
(2) Weighing tray holder 1
(3)
Glass container ∅ 90 mm, h = 60 mm
1
(4) Platform for glass c ontainer 1
(5)
Thermometer
1
(5) -1 Rubber stop for t hermometer 1
(6) Holder for thermometer 1
(7) Glass sinker 1
Operating instructions 1
(7)
4 ACS-A03-BA-e-1210
Fig. 2: Installed density set KERN ACS-A03
Fig. 3: Immersion basket for solid matter
A Upper sample dish (weight of the sample in air)
B Lower sample dish (weight of the sample in measuring liquid)
ACS-A03-BA-e-1210 5
ρ =
A
A-B
o
ρ
ρ =
m
V
2 Principle of Densi ty Determinati on
Three physical magnitudes are the volume and the mass of bodies as well as the
density of matter. In density mass and volume are related.
Density [ ρ ] is the relation of mass [ m ] to volume [ V ].
SI-unit of density is kilogram divided by cubic meter (kg/m³). 1 kg/m³ equals the
density of a homogenous body that, for a mass of 1 kg, has the volume of 1 m³.
Additional frequently applied units include:
, ,
The application of this density determination set in combination with the KERN
ABS/ABJ balances provides fast and safe determ ination of solids and fluids. O ur set
uses the "Principle of A rchim edes" to determine density:
BUOYANCY IS A FORCE. IT AFFECTS A BODY THAT IS IMMERSED INTO A FLUID. THE
BUOYANCY OF THE BODY EQUALS THE WEIGHT FORCE OF THE DISPLACED FLUID. THE
FORCE OF BUOYANCY ACTS VERTICALLY UPWARDS.
Thus, density is calculated according to the formulae below:
To determine the densit y of solid matter
Our balances enable weighing of solids in air [ A ] as well as water [ B ]. If the density
of the buoyancy medium is known [ ρo ] the density of the solid [ ρ ] is calculated as
follows:
ρ = density of sample
A = weight of the sample in air
B = weight of sample in measuring fluid
ρ
o
= density of measuring fluid
1
g
cm
3
1
kg
m
3
1
g
l
6 ACS-A03-BA-e-1210
ρ =
V
A-B
Determining density of liquids
The density of a fluid is determined with the help of a sinker providing a known
volume [ V ]. The sinker is weighed in air [ A ] as well as in the sample fluid [ B ].
According to the Archimedes’ Principle a body immersed in a fluid experiences a
force of buoyancy. [ G ]. This for ce equal s t he w eight force of the fluid displaced by
the volume of the body.
The volume [ V ] of the immersed body equals the volum e of the displaced fluid.
G = buoyancy of sinker
Buoyancy of sinker =
Weight of the sinker in air [ A ] - weight sinker in sample liquid [ B ]
From this follows:
ρ = density of sample fluid
A = weight of sinker in air
B = weight of sinker in sample fluid
V = volume of sinker*
* If the volume of the sinker is unknown, this can be determined by a solid body
density measurement e.g. in water and be calculated as follows.
V = volume of sinker
A = weight of sinker in air
B = weight of sinker in water
ρ
W
= density of water
2.1 Influencing magnitudes and error sources
Air pressure
Temperature
Volume deviation of the sinker
Surface tension of the liquid
Air bubbles
Immersion depth of the sample dish of sinker
Porosity of the solid
ACS-A03-BA-e-1210 7
3 Installing th e den sity determination set
• If necessary, carry out necessary adjustment before installation of the density
set.
• When the density set is installed, correct adjustment is not possible.
• For reasons of adjustment, take away the density set and place the standard
weighing plate.
1. Switch off balance and separate it from the power supply.
2. Remove standard weighing plate,
screening ring and weighing plate
carrier.
3. Insert balance tray holder
carefully
4. Place the platform for glass
containers in a way that it does not
touch the balance tray holder.
5. Mount the immersion basket; ens ur e
that it hangs centrically in the recess
of the weighing tray holder.
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