SPECIFIC GRAVITY MEASURING KIT
ƒ
ƒ
ƒ
for ASB series
for BPS series
for ABX series
MRCLTD
HAGAVISH 3 HOLON ISRAEL
TEL. 972-3-5595252
FAX. 972-3-5594529
E-Mail: [email protected]
Contents
1. INTRODUCTION .............................................................................................. 3 2. PRINCIPLE OF DENSITY MEASUREMENT ................................................... 4 2.1. DEFINITIONS ........................................................................................... 4 2.2. ERROR FACTORS ................................................................................... 5 3. MEASURING KIT – COMPONENTS ............................................................... 7 3.1. Measuring kit for precision balances .................................... .................... 7 3.2. Measuring kit for analytical balances ........................................................ 8 4. INSTALLATION OF THE COMPONENTS FOR ANALYTICAL
BALANCES ......................................................................................................... 9 4.1 INSTALLATION FOR THE COMPONENTS FOR PRECISION
BALANCES ................................................................................................... 10 4.2 INSTALLATION FOR THE COMPONENTS FOR ANALYTICAL
BALANCES AS SERIES ................................................................................ 11 5. MEASURING THE DENSITY FOR BALANCES............................................ 12 5.1. DENSITY FUNCTION IN THE BALANCE MENU ................................... 12 5.2. FUNCTION ACTIVATION ....................................................................... 13 5.3. SOLID DENSITY – VIEW MENU ............................................................ 13 5.4. LIQUID DENSITY – VIEW MENU ........................................................... 14 5.5. MEASURING THE DENSITY OF A SOLID ............................................ 15 5.6. MEASURING THE DENSITY OF A LIQUID ........................................... 18 6. MEASURING THE DENSITY OF SOLIDS FOR BALANCES PS SERIES.... 21 6.1. MEASURING THE DENSITY OF SOLIDS ............................................. 21 6.2. MEASURING THE DENSITY OF A LIQUID ........................................... 27 7. MEASURING THE DENSITY BALANCES .................................................... 31 7.1. DENSITY FUNCTION IN THE BALANCE MENU ................................... 31 7.2. MEASURING THE DENSITY OF A SOLIDS .......................................... 32 7.3. MEASURING THE DENSITY OF A LIQUID ........................................... 36 8. MANUFACTURER’S RECOMMENDATIONS ............................................... 41 Table 1. Dependences of density of distilled water on the temperature....... 42 Table 2. Dependences of density of water on the temperature (Official
Journal of Measures No 7/94) ...................................................................... 43 Table 3. Density of some substances (Engineer Mechanic Guide
Volume 1)...................................................................................................... 44 Table 4. Density if some liquids at 20 °C (Engineer Mechanic Guide
Volume 1)...................................................................................................... 44 -2-
1. INTRODUCTION
Density of solids and liquids is measured in most of the laboratories.
0R& company prepared software which improves process of
measuring density.
In traditional method operator has to perform many laborious
measurement and toilsome measurements.
In effect the result of density measurement can be faulty. User needs a
lot of time to determine density of liquid or solid.
If balances with function for measure density of solids or liquids is used
this procedure can be simplified and quickened. Time which user needs
to receive final result is short because all countings are performed by
balance software. User operates the balance keyboard, puts samples on
the pans and hooks the float only.
The density of solids and liquids can be determined by the
measuring kit. It is part of the additional equipment of laboratory balance.
The software has following advantages:
• Simplicity of operation (all activities are presented on the
display to user),
• reliability (all counting are done automatically),
• fast processing of the data (user receives the result after
determination sample mass in water or float in the liquid),
• reliable processing of the data (before every measurement
the indication is set to zero. The results are reliable),
• printing results on any printer or sending them to computer to
transform them.
-3-
2. PRINCIPLE OF DENSITY MEASUREMENT
2.1. DEFINITIONS
• Density
Density refers to the total amount of mass of sample per unit
volume.
/
ρ
M
V
- density
- mass
- volume
• Specific gravity
Specific gravity refers to the ratio of the density of a sample to the
density of pure water (with the same volume as that of the
sample) at 4oC, at pressure 1013,25 hPa.
S
M
V
ρn
- specific gravity
- mass
- volume
- density of water at 4oC, at pressure 1013,25 hPa
• Archimedes’ Principle
A body immersed in a fluid undergoes an apparent loss in weight
equal to the weight of the fluid it displaces.
• Density of solid
The density of solid can be obtained according to the weight of
the sample of the specimen in air and the density of the liquid.
ρ
A
B
ρo
- density of specimen
- weight in air
- weight in liquid
- density of liquid
-4-
• Density of liquid
The density of a liquid is obtained in accordance with following
formula:
ρ
A
B
V
d
- density of liquid
- weight of float in air
- weight of float in liquid
- volume of float
- density of air ( max 0,001 g/cm3 )
2.2. ERROR FACTORS
The software counts and shows density results on the digital display with
capacity 0,001 g/cm3. The result may have some errors.
• Error of mass measurement
Sample mass (in the air and in the water) is obtained by balance
with accuracy 0,001g.
• Buoyancy of Air
The buoyancy of air is obtained by:
1
t
p
0,0012932
0,0036728
1013,25
- air temperature [oC]
- air pressure
• Temperature of liquid
When the density of solid is measured the density of liquid
changes with the temperature.
Density of liquid (H2O and C2H5OH) is collected from tabels in
the balance processor by the balance software depending on
temperature of liquid before the measurement.
Density of other liquid is noted in the balance memory by user
before density measurement.
Corrections of density of distilled water and alcohol are noted by the
balance software automatically.
-5-
• Volume of Float
The tolerance of measured value of the volume of float is ± 0,005
cm3.
• Surface tension
When the density of a solid is measured a force (surface
tension) is applied to the pan between the wire (0,2 mm in dia) of
the pan and the surface of the liquid. This force has no influence
on result of measurement.
• Bubbles
The buoyancy of a bubble of 1 mm in diameter is about 0,5 mg.
Stickiness of bubbles depends on the shape and material of a
specimen. Make measurements considering these characteristic
of bubbles.
Air bubbles stick to greasy surfaces easily.
-6-
3. MEASURING KIT – COMPONENTS
3.1. Measuring kit for precision balances
Draw 1. Components of the KIT for precision balances
Components of the kit:
1
2
3
4
5
6
Pan stand
Bottom pan
Wire
Top pan for density of
solids measurement
Beaker
Float hook
7
8
9
Thermometer
Thermometer clamp
Float
10
Beaker stand
11
Additional pan stand
-7-
3.2. Measuring kit for analytical balances
Draw 2. Components of the KIT for analytical balances
Components of the kit:
1
2
3
4
5
6
Beaker stand
Pan stand
Float
Beaker
Thermometer clamp
Thermometer
7
8
9
10
11
12
Wire
Float hook
Top pan
Wire
Bottom pan
Additional weights
Attention:
− Store the components in the kit box.
− Do not put pans set and float on the table because these elements
can be damaged.
− If pans set or float are not used they should be stored on additional
stand.
-8-
4. INSTALLATION OF THE COMPONENTS FOR ANALYTICAL
BALANCES XA SERIES
Take the pan off. Install gravity measuring kit as it is presented on the
drawing below.
Draw 3. installation of the components
-9-
4.1 INSTALLATION FOR THE COMPONENTS FOR PRECISION
BALANCES
Draw 3.1. installation of the components
- 10 -
5. MEASURING THE DENSITY
BALANCES
5.1. DENSITY FUNCTION IN THE BALANCE MENU
Draw 4. The balance menu – density function
The density value should be set as 1 (enabled). It is possible to get
directly to this function through MODE button.
Draw 5. Buttons on the balance keyboard
If specific gravity measuring kit is installed on the balance it is not possible to
calibrate the balance correctly. To perform calibration process put the pan
instead of gravity measuring kit.
- 12 -
1. INTRODUCTION
Density of solids and liquids is measured in most of the laboratories.
R& company prepared software which improves process of
measuring density.
In traditional method operator has to perform many laborious
measurement and toilsome measurements.
In effect the result of density measurement can be faulty. User needs a
lot of time to determine density of liquid or solid.
If balances with function for measure density of solids or liquids is used
this procedure can be simplified and quickened. Time which user needs
to receive final result is short because all countings are performed by
balance software. User operates the balance keyboard, puts samples on
the pans and hooks the float only.
The density of solids and liquids can be determined by the
measuring kit. It is part of the additional equipment of laboratory balance.
The software has following advantages:
• Simplicity of operation (all activities are presented on the
display to user),
• reliability (all counting are done automatically),
• fast processing of the data (user receives the result after
determination sample mass in water or float in the liquid),
• reliable processing of the data (before every measurement
the indication is set to zero. The results are reliable),
• printing results on any printer or sending them to computer to
transform them.
-3-
Temperature
Temperature which is presented on the display and should be written
during the procedure. For OTHER read out the density in the table. The
tables show dependences on the temperature.
Density
Density of liquid which depends on the temperature. For WATER and
ALCOHOL this value is counted automatically. For OTHER write the
density of liquid.
Statistics
Statistics counting for following density measurements.
Run
Start the procedure.
5.4. LIQUID DENSITY – VIEW MENU
Draw 8. Liquid density – view menu
Procedure
Select the procedure of density of solids and liquids measuring.
Sinker volume
Capacity of the float is presented on the float hook. Record this value in
the balance memory.
Statistics
Statistics counting for following density measurements.
Run
Start the procedure.
- 14 -
-
Press the ENTER button when the result is stable.
End of procedure.
Draw 25. End of procedure – final result
Function keys:
Draw 26. Function keys
6. MEASURING THE DENSITY OF SOLIDS
6.1. MEASURING THE DENSITY OF SOLIDS
Take the pan off and install measuring kit following point. 7. Set the
beaker on the stand so that it does not touch the pan. Attach the
thermometer clamp to the beaker and insert the thermometer in the
thermometer clamp holes. Pour a liquid into the beaker (distilling water,
alcohol or any other with known density)to about ¾ of the capacity. Place
the pan on the pan stand centrally. Put the pan stand in the central
position of beaker, then check the temperature in the beaker. Remember
to keep the temperature inside beaker stable during measurements (the
density of liquids depends on the temperature - can change results of
measurement). The kit is prepared to measurements now.
- 21 -
Procedure:
•
•
•
Press key Mode, pressing UNITS key choose submenu F6
d_Co,
Select one of the 3 liquids H20 (disilled water), C2H5OH (spirit
100% ± 0.1% in temp. 200C) or Another (any other liquid with
known density),
for H20 and C2H5OH, give the temperature of the liquid and
follow below instructions,
Draw. 27. Procedure of density solids determination (selected liquid is H20).
- 22 -
•
For selected liquid Another, give the liquid density and follow
the procedure on the picture below
Draw. 28. Procedure of solids density determination (selected liquid: Another).
•
•
After selecting type of the liquid the balance shows Load A then
zero (if the balance does not show zero press
ESC/ZEROTARA),
Then put the sample on the upper pan and weight it in the air.
- 23 -
•
Balance shows density in [g/cm3].
During measurements check if there is any air bubbles on the surface of the
sample. They can cause errors in measurements. .
To select other liquid press F:
Draw. 32. Method of reselecting liquid
To return to weighing press Mode and then press Zero/Tara:
Draw. 33. Return to weighing
- 26 -
To weight the sample again press the key Units:
Draw. 34. Procedure of return to weighing.
6.2. MEASURING THE DENSITY OF A LIQUID
Take the pan off ,install the measuring kit following the point 7. If „null” is
on the display, use additional load on the kit. Then press Zero/Tara, if
there is different value to zero on the display. Then pour the liquid into
the beaker – the plunger should be immersed in the liquid completly.
Procedure
•
•
Press key Mode, then select submenu F7 d_Li,
Then enter capacity of the plunger, accuracy of the capacity
depends on the value given
- 27 -
Draw. 35. Measuring the density of liquids.
•
After capacity of the plunger is entered into balance memory
(key Print/Enter) balance shows command Load A and zero (if
the balance does not show zero press ESC/ZEROTARA),
- 28 -
To enter density of the pluger again, press F:
Draw. 37. Entering density of plunger
To return to weighing press Units, and then key Zero/Tara:
Draw. 38. Return to weighing.
To restart weighing plunger in the air press Units:
Draw. 39. Procedure of beginning following weighing.
- 30 -
7. MEASURING THE DENSITY BALANCES
7.1. DENSITY FUNCTION IN THE BALANCE MENU
Draw 40. Balances menu – LCD series
- 31 -
7.2. MEASURING THE DENSITY OF A SOLIDS
Procedure:
−
−
−
Press key MODE. Pressing UNITS key, choose F6 d_Co.
Press PRINT to start density function.
Press UNITS key and select liquid in with density will be
determined.
Draw 41. Solids density – select liquid
Thickness of solids can be tested in one of 3 liquids:
• H2O (distilled water),
• C2H5OH (spirit 100% +/- 0.1% in temp. 20°C),
• AnotHEr (another liquid with known thickness).
− After selecting liquid confirm by PRINT.
- 32 -
−
If H2O or C2H5OH are selected the program moves to
following step, introducing actual liquid temperature. The
information on the display enables to introduce liquid
temperature from the thermometer. Enter the temperature
using UNITS or MODE key.
Draw 42. Solids density – set temperature
−
After adjusting the temperature, press PRINT key to confirm
it.
If AnotHEr liquid was selected after pressing ENTER key the program
moves to following step when the density of the liquid should be noted.
Introduce the density value of this liquid by function key of the balance.
−
−
−
Press the UNITS or MODE key to change the digit value.
Press the F key to select the digit.
After adjusting the temperature press PRINT key to confirm
it.
After writing information about the liquid parameters the balance
software moves to following process steps automatically. Commands
which inform user that the software is ready to receipt following data
(mass of the sample in air and in liquid) necessary to correct counting
density of examined sample.
Draw 43. Solids density – measure in air
- 33 -
Key function after procedure
The result is presented on the display in [g/cm3]. It does not change
even when the sample is taken off. Press F key to do back to menu.
7.3. MEASURING THE DENSITY OF A LIQUID
Basic element for measuring thickness of liquid is glass plunger. It has
precise capacity shown on hook.
INSTALLATION
1. Disassemble the pan.
2. Set the pan stand on the bumpers.
3. Set the beaker stand so that it does not touch the pan stand (as
it is presented on below drawing).
4. Attach the thermometer clamp to the beaker and insert the
thermometer in the thermometer clamp holes.
5. Pour liquid (about ¾ of the capacity) – which specific gravity is
known – into the beaker and place the beaker on the beaker
stand.
6. Hook the float on the float hook.
7. Wait until the temperature stabilizes, the result on the
thermometer do not change.
8. Preparations for measurement are now completed.
- 36 -
−
−
−
Press PRINT to start density function.
Order to write float capacity vol appears on the display.
The volume of float can be noted with the same accuracy as
the balance shows. If actual scale interval is 0.001 g in the
balance the volume stamped on the float hook should be
noted with accuracy to 3rd place after the decimal point.
Write the volume of float using the keys:
−
−
−
Press the MODE or UNITS key to change the digit value.
Press the F key to select the digit.
Press PRINT key to confirm value.
If the density of liquid is performed last float capacity appears on the
display. Check if it is the same as the volume of the float stamped on the
hook.
Draw 49. Liquids density – set volume of float
The volume of the float is noted into the balance memory. LoAd A and
0.000 appears on the display.
Draw 50. Liquids density – step 1
Weight the float in air, hook it on the pan stand without beaker.
- 38 -
The result is presented on the display in [g/cm3]. It does not change
even when the sample is taken off.
8. MANUFACTURER’S RECOMMENDATIONS
1. Density of solids should be determined after more than one
measurement.
2. Examined sample should be degreased.
3. If the sample is oval it is difficult to catch it by the tweezers. It is
necessary to cut notch which simplifies catching the sample.
4. The surface of the sample cannot be rough. Air bubbles fasten to
rough surfaces easily.
5. Before every measurement dry the sample. If the sample is not
dried the sample mass in air is different during following
measurement and density counted by the balance software is
faulty.
6. Set samples on the pans gently to avoid impacts.
7. Adjust the amount of the liquid so that the bottom pan arm is all
immersed.
8. Select the sample mass to size of the pans.
9. The sample mass should be bigger than 5g.
10. Element which can cause errors is water on the tweezers. The
tweezers should be also dried.
11. Density of liquids should be determined after few measurements.
12. Temperature of examined temperature should be stable.
13. The beaker should be degreased. If the surface is greasy air
bubbles fasten easily to the sample and causes errors.
14. Wash the beaker before the measurement.
15. Adjust the amount of the liquid so that the specimen is 10 - 15 mm
below the surface of the liquid.
16. Hook the float gently to avoid impacts.
17. Element which can cause errors is examined liquid. It fastens to
the float. The mass of the liquid can be different in following
measurements. The float should be dried after every weighing in
liquid.
- 41 -
CAUTION
− Do not use plastic cloth to dry the float because it causes electric
charge. It is recommended to wet the cloth in antistatic agent.
− If the float is damaged during exploitation (breaks) it is not
repared under the conditions of guarantee.
Table 1. Dependences of density of distilled water on the
temperature
TEMP
0
1
2
3
4
0
0,99984
0,99990
0,99994
0,99996
0,99997
10
0,99970
0,99961
0,99949
0,99938
0,99924
20
0,99820
0,99799
0,99777
0,99754
0,99730
30
0,99565
0,99934
0,99503
0,99470
0,99437
TEMP
5
6
7
8
9
0
0,99996
0,99994
0,99990
0,99985
0,99978
10
0,99910
0,99894
0,99877
0,99860
0,99841
20
0,99704
0,99678
0,99651
0,99623
0,99594
30
0,99403
0,99368
0,99333
0,99297
0,99259
- 42 -
Table 2. Dependences of density of water on the temperature
(Official Journal of Measures No 7/94)
[°C]
Density of water [g/cm3]
17,0
0,9988
17,5
0,9987
18,0
0,9986
18,5
0,9985
19,0
0,9984
19,5
0.9983
20,0
0,9982
20,5
0,9981
21,0
0,9980
21,5
0.9979
22,0
0,9978
22,5
0,9977
23,0
0,9975
- 43 -
Table 3. Density of some substances
(Engineer Mechanic Guide Volume 1)
Name
Bakelite
Cotton
Trick
Sugar
Wood oak
Felt
Gum
Linoleum
Building paper
Paper
Leather
Polished plate
glass
Peat
Calcareous
plaster
Glass wool
Wax
Density
[kg/m3]
1270
1300
1400
1600
900
300
1200
1200
1100
900
1000
Copper
Aluminium
Iron
Platinum
Gold
Silver
Molibden
Tin
Lead
Cadmium
Mercury
Density
[g/cm3]
8,9
2,7
7,8
21,4
19,3
10,5
10,2
7,3
11,4
8,65
13,6
2550
Ind
7,3
130
Bismuth
9,9
1700
Tantal
16,6
200
950 – 980
Nickel
Brass
8,9
8,4 - 8,7
Name
Table 4. Density if some liquids at 20 °C
(Engineer Mechanic Guide Volume 1)
Name
Ammonia
Petrol
Glycerine
Nitric acid 20%
density
[kg/m3]
610
680 – 740
1260
1120
Name
Spindle oil
Kerosene
Ice 0o C
Acetic acid
- 44 -
Density
[kg/m3]
871
800 - 850
917,6
1050