KERN ABT-A01 User manual

GB
KERN ABT-A01
Version 1.0 2/2007
Operating Manual
Density Determination Set for Analytical Balance KERN ABT
Contents:
1INTRODUCTION............................................................................................... 24
1.1 SCOPE OF DELIVERY ..................................................................................... 25
2INSTALLING THE DENSITY DETERMINATION SET...................................... 27
3PRINCIPLE OF DENSITY DETERMINATION.................................................. 29
3.1 INFLUENCING MAGNITUDES AND ERROR SOURCES............................................ 30
4DENSITY DETERMINATION OF SOLIDS........................................................ 31
4.1 ACTIVATE FUNCTION ..................................................................................... 32
4.2 ENTERING DENSITY FOR FLUID ...................................................................... 33
4.3 CARRYING OUT MEASUREMENT..................................................................... 34
5DETERMINING DENSITY OF LIQUIDS ........................................................... 34
5.1 ACTIVATE FUNCTION ..................................................................................... 34
5.2 ENTERING DENSITY OF GLASS PLUMMET........................................................ 36
5.3 CARRYING OUT MEASUREMENT..................................................................... 37
6PRECONDITIONS FOR PRECISE MEASUREMENTS.................................... 38
6.1 CALCULATION OF RESULTS............................................................................ 38
6.2 INFLUENCE FACTORS FOR MEASUREMENT ERRORS......................................... 39
6.2.1 Air bubbles.............................................................................................. 39
6.2.2 Solid Specimen....................................................................................... 39
6.2.3 Liquids.................................................................................................... 39
6.2.4 Surface................................................................................................... 39
6.2.5 Glass Plummet for Measuring Fluids...................................................... 40
6.3 GENERAL INFORMATION ................................................................................ 40
6.3.1 Density / Relative Density....................................................................... 40
6.3.2 Drift of Balance Display .......................................................................... 40
7DENSITY TABLE FOR FLUIDS ....................................................................... 41
8UNCERTAINTY OF MEASUREMENT FOR DENSITY DETERMINATION OF
SOLIDS.................................................................................................................... 42
9USER INSTRUCTIONS..................................................................................... 43
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1 Introduction
Safety instructions:
In order to guarantee a safe and smooth operation of this instrument, you have to
comply with the precautions below.
1. Carefully read the operating instructions.
2. Handle this set and the balance with care as they are precision instruments.
This set contains parts made of glass. Protect all parts against shocks and
impacts.
3. Do not disassemble this set nor the balance.
KERN ABT-A01 Density determination set for analytical balances of the
KERN ABT series (readability d= 0.1 mg).
This set is designed for the efficient determination of the density of solids by means
of an analytical balance.
In addition the density of fluids may be determined by means of an additional
plummet.
These operating instructions only describe the operation of the density determination
set. For further information on how to operate your balance please refer to the
operating instructions supplied with each balance.
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1.1 Scope of delivery
SAMPLE DISH
FILTER BOWL
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No. Designation
1 Platform assembly (sample dish and sifting bowl), 2 x
2 Weighing platform with rack
3 Beaker
4 Platform for glass beaker
5 Thermometer
6 Holder for thermometer
7 --
8 Glass plummet
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2 Installing the density determination set
1. Turn off and disconnect the power supply for the balance
2. Open the lateral glass doors of the weighing space of the balance and remove the
grading ring, the weighing plate and the support of the weighing plate.
3. Carefully insert the weighing platform with rack onto the floor of the weighing
space.
4. Place the platform for the glass beaker above it without touching the weighing
platform, as shown.
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5. Attach the platform assembly (sample dish and sifting bowl) to the rack of the
weighing platform. In doing so, bear in mind that the centering of the upper sample
dish matches the notch in the upper part of the weighing platform.
6. Close the glass doors and connect the power supply for the balance. Wait for the
auto test of the balance and the display message "oFF“. Some models additionally
carry out an automatic adjustment before displaying “oFF“. (Connect the balance to
the platform assembly but without any fluid in the glass beaker. )
7. Turn on the balance by pressing the [ON/OFF] key, so that gram appears on the
display.
8. Attach the holder with thermometer to the glass beaker. Fill the glass beaker with
known fluid (for density determination of solids) or test fluid (for density determination
of fluids).
9. To be able to place the glass beaker in the centre of the platform, the platform
assembly must first be removed from the rack.
10. Reattach the platform assembly to the rack and ensure that the sifting bowl does
not touch the glass beaker.
11. Observe the waiting time until the test fluid, the known fluid, the instruments or
the plummet have the same temperature. For the balance also observe the required
warm-up time. (For details please refer to the operating instructions for the balance)
Attention:
•The platform for the beaker must not touch the frame!
•When the density set is installed, correct adjustment is not possible. To
achieve correct adjustment reinsert the weighing plate.
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3 Principle of Density Determination
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 ].
ρ =
A
A
-
B
o
ρ
ρ = m
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:
1
g
c
m
3
,
1k
g
m
3
,
1
g
l
The application of this density determination set in combination with the KERN ABT
balance provides fast and safe determination of solids and fluids. Our set uses the
"Principle of Archimedes" 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:
Density determination of solids:
This balance enables 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
ρo = density of measuring fluid
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Determining density of liquids:
The density of a fluid is determined with the help of a plummet providing a known
volume [ V ]. The plummet 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 force equals the weight force of the fluid displaced by
the volume of the body.
The volume [ V ] of the immersed body equals the volume of the displaced fluid.
ρ =
G
V
G = buoyancy of plummet
Buoyancy of plummet =
Weight of the sinker in air [ A ] - weight sinker in sample liquid [ B ]
From this follows:
ρ =
V
A
-
B
L
ρ
+
ρ= density of sample fluid
A = weight of plummet in air
B = weight of plummet in sample fluid
V = volume of plummet
ρL = air density (0.0012 g/cm³)
3.1 Influencing magnitudes and error sources
ÖAir pressure
ÖTemperature
ÖVolume deviance of the sinker (±0.005 cm3)
ÖSurface tension of the liquid
ÖAir bubbles
ÖImmersion depth of the sample dish of sinker
ÖPorosity of the solid
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4 Density determination of solids
Prepare balance as described in chapter 2 "Installation of density determination set".
ÖInstall holder for the thermometer on beaker rim.
ÖSuspend thermometer
ÖFill your measuring liquid, whose density ρois known, into the beaker.
Filling height should be approx. ¾ of the capacity.
ÖPlace beaker in the centre of the platform
ÖSuspend sample dish from the centre of the frame
ÖHeat measuring liquid until temperature is constant.
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4.1 Activate function
Press several times the [UNIT] key to change the display between activated units,
piece counting, percentage and density determination mode.
This does not require additional software.
Settings have to be activated in the menu:
Repeatedly press the [CAL] key until "FUnC.SEL" appears.
Press [TARE] key
(Example) Repeatedly press the [CAL] key until "Unit.SEL" appears.
Press [TARE] key
Use the [CAL] key, to select the settings below:
„ U- ,d“ („ ,“ this is an upside down triangle)
Current settings are indicated by the standstill display ( ).
Confirm your selection by pressing the [TARE] key.
The [TARE] key is also used to deactivate a unit or function if
the corresponding setting with standstill display is shown in the
display.
Repeatedly press the [ON/OFF] key. This takes you back to the
menu/weighing mode.
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