KERN & Sohn GmbH Ziegelei 1 D-72336 Balingen E-Mail: info@kern-sohn.com Tel: +49-[0]7433- 9933-0 Fax: +49-[0]7433-9933-149 Internet: www.kern-sohn.com Operating instruction Set for density determination KERN ALS/PLS-A01 Version 1.
KERN ALS/PLS-A01 GB Version 1.5 04/2008 Operating instruction Set for density determination for precision and analytical balances KERN ALT, KERN PLT, KERN ALS/ALJ, KERN ALS..N/ALJ..N, KERN PLS/PLJ Contents: 1 INTRODUCTION ............................................................................................................................ 4 1.1 SCOPE OF DELIVERY .................................................................................................................
1 Introduction When acquiring a density set as accessory for your electronic balance there are 2 models available: KERN ALS-A01 for analysing balances of the KERN ALT, KERN ALS/ALJ and KERN ALS..N/ALJ..N series (only suitable for models with readability d = 0.1 mg). KERN PLS-A01 for analysing balances of the KERN PLS/PLJ and KERN PLT series (only suitable for models with readability d = 1 mg). This manual only descries working with the density determination set.
KERN PLS-A01 No.
2 Installation of density determination set Ö Remove the following parts from the balance Model KERN ALT: (1) Weighing plate (2) Screening ring (1) Weighing plate (2) Support for weighing plate (3) Screening ring Model KERN ALS/ALJ: 1 2 3 6 ALS/PLS-A01-BA-e-0815
Model KERN PLS/PLJ, PLT: (1) Windshield cover (2) Windshield (3) Weighing plate Ö Installation of density determination set Models KERN ALS/ALJ, KERN ALT: Central 1-point receptacle ALS/PLS-A01-BA-e-0815 7
Models KERN ALS..N/ALJ..
Models KERN PLS/PLJ, PLT: 4-point receptacle Attention: • The platform for the beaker must not touch the frame! • When the density set is installed, adjustment is not possible. For adjustment, re-install weighing plate.
3 Principle of density determination Three physical magnitudes are the volume and the mass of bodies as well as the density of matter. Mass and volume are connected with each other in density: Density [ ( ] is the relation of mass [ m ] to volume [ V ]. 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.
For density determination of liquids The density of a liquid is determined by using a sinker, whose volume ([ V ] is known see embossment). The sinker is weighed in air [ A ], as well as in sample liquid [ B ]. According to the law of Archimedes, a body that immersed in a liquid is exposed to buoyancy [ G ]. The absolute value of this force equals the weight of the liquid displace by the volume of the body. The volume [ V ] of the immersed body equals the volume of the displaced liquid.
4 Density determination of solids Prepare balance as in chapter 2 "Installation of density determination set". Ö Install holder for the thermometer on beaker rim. Ö Suspend thermometer Ö Fill your measuring liquid, whose density ρo is known, into the beaker. Filling height should be approx. ¾ of the capacity. Ö Place beaker in the centre of the platform Ö Suspend sample dishes from the centre of the frame Ö Heat measuring liquid until temperature is constant.
4.1 Models KERN ALS/ALJ/PLS/PLJ Key Display Description Turn on balance; balance will carry out self-check. Wait until the stability and balance zero-display shows or Menu selection: Press TARE -key; the display shows horizontal lines; while this display is shown, press the F -key. The first function “Add“ or “Pieces” appears. Keep the F –key pressed until the density function for solids "Co" is displayed. Confirm your selection. The balance is now in density determination mode for solids.
Select measuring liquid: Use the F -button to choose between the following settings: H20 = Distilled water C2H5OH = Ethanol nother = Measuring liquid of your choice, whose density is known If you selected distilled water or ethanol as measuring liquid, enter the temperature of the measuring liquid in the next menu step. Confirm your selection. TE-L 0O Read the temperature of the measuring liquid from the suspended thermometer and then enter it as follows (current number is blinking).
If you selected “nothEr“ as measuring liquid enter the density of your measuring liquid in the next menu step. Confirm your selection. z00000O z00000O z90000O Enter the density of your measuring liquid (the current number is blinking). Use the ON/OFF – key to select the place you want to change, the currently active place is blinking Use the F – key to change the value of the number z997800 Confirm your entry.
After entering the parameters for the measuring liquid follow the automatic user interface of the balance. LQADA Place the solid in the upper sample dish 1.928 g Wait until the weight display of the balance is stable. Actuating the PRINT -key will safe the weight of the sample in air. LQADL The display Load L prompts you to remove the sample from the upper sample dish and to place it into the lower sieve dish.
g Wait until the weight display of the balance is stable. Actuating the PRINT – key will save the weight of the sample in measuring liquid. F 1.990 g The density of the sample (ρ) is now automatically calculated and shown on the display [ g/cm3 ]. 1.788 Data output to the serial interface RS 232. The result is issued in g/cm³. Remove sample; the measuring result still on display. Use the TARE -key to return to weighing mode.
4.2 Models ALJ..N/ALS..N Procedure: . Pressing UNITS key, choose F6 d_Co. − Press key − Press PRINT to start density function. − Press UNITS key and select liquid in with density will be determined. Ø 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.
If AnotHEr liquid was selected after pressing PRINT 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 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.
− LoAd L appears on the display. It is order to take a sample off top pan and put it on the bottom pan. Press the PRINT key when the result is stable. This mass is noted in the balance memory as mass in liquid and density of a sample is counted automatic. Check if there are any air bubbles fastened to a sample. It could cause errors during measurements. 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.
4.3 Models KERN ALT, PLT Key Display 20.02.05 P 8 01 02 03 04 05 06 07 08 Mode Parts Count Checkweighing Filling Percont Animal Density Formulation Statistics 20.02.
Parameter 02 Liquid The current menu item is blinking Density setup M6 or 01 Procedure 02 Liquid 03 Temperature 04 Density 05 Statistics 06 Run SOLID DENSITY WATER C 22 g/cm3 1.0546 OFF Select your measuring liquid: Water = Distilled water Alcohol = Ethanol Other = Measuring liquid of your choice whose density is known Confirm your selection.
If you selected Other as measuring liquid enter the density of your measuring liquid (temperature dependent) in the next menu step. Parameter 04 Density Density setup M6 01 Procedure 02 Liquid 03 Temperature 04 Density 05 Statistics 06 Run SOLID DENSITY WATER C 22 g/cm3 1.0546 OFF Enter the density of your measuring liquid (the current menu item is blinking) Change the value of the number or Select the place to be changed, the active place is blinking or Confirm your selection.
Parameter 06 Run After entering the parameters, follow the automatic user interface of the balance to determine density. Density setup M6 01 Procedure 02 Liquid 03 Temperature 04 Density 05 Statistics 06 Run 27.3.05 Density W e ig h in g in t h e a ir. P la c e a n o b je c t [ E n te r ] 0.0001 g 0% 27.3.05 With the parameter selection "06 Run" to get into density determination mode and the graphic display appears. 100% Density W e ig h in g in t h e a ir.
27.3.05 0% 27.3.05 0% Density W e ig h in g in a liq u i d P la c e a n o b je c t [ E n te r ] 2.5200 g 100% Density W e ig h in g in a liq u i d P la c e a n o b je c t [ E n te r ] 0.0000 g 100% You will be prompted to remove the sample from the upper sample dish and place it into the lower sieve dish. To do this, use the supplied pincers and ensure that there are no air bubbles adhere to the solid. 27.3.05 0% 27.3.05 W 1=2.
Return to weighing mode: 20.02.05 M0 M1 M2 M3 M4 M5 M6 Mode Basic weighing Parts counting Checkweighing Filling Percent Animal weighing Density Cursor (►) to „M0 Basic weighing“ Weighing 15.10.01 13:47:32 0.0000 Overview of display: 6 5 4 27.3.05 W 1=2.5200 Density W 2=2.0035 ... t o c o n t in u e 0% 3 D=0.9986 [ U n it s ] 4.87 g/ cm3 2 100% 1 1. 2. 3. 4. 5. 6.
5 Density determination of liquids Prepare balance as described in chapter 2 "Installation of density determination set". PLS/PLJ ALS/ALJ Ö Install holder for the thermometer on beaker rim. Ö Suspend thermometer Ö Fill your measuring liquid into the beaker. Filling height should be approx. ¾ of the capacity. Ö Heat measuring liquid until temperature is constant.
noKK Ö If the display shows the error message " ", mount the additional weights for balancing the removed weighing plate on the side of the frame.
5.1 Models KERN ALS/ALJ/PLS/PLJ Key Display Description Turn on balance; balance will carry out self-check. Wait until the stability and balance zero-display shows Menu TARE-key; the display shows horizontal lines; while this display is shown, press the F -key. The first function “Add“ appears. -L - VOL ALS/PLS-A01-BA-e-0815 Keep the F- key pressed, until the density function for liquids die "Li" appears. Confirm your selection. The balance is now in density determination mode for liquids.
00000.000g For first commissioning, the display will only show zeroes. 00009.998g If density determinations have been carried out previously the volume of the sinker last used is displayed. Enter the volume of the sinker (see embossment on suspension hook, information in cm3 e.g. 9.9984 cm³): 00000.000g Use the ON/OFF – key to select the place you want to change, the currently active place is blinking 00009.000g Use the F – key to change the value of the number 00009.998g Confirm your entry.
Determination of the weight sinker in air Suspend sinker from the centre, Measurement is carried out without beaker 10.256 g Wait until the weight display of the balance is stable. Actuating the PRINT – key will save the weight of the sinker in air. Determination of the weight sinker in sample liquid LQADL Remove sinker Place beaker with measuring liquid in the centre of the platform. Immerse sinker in measuring liquid and suspend from frame. The measuring liquid should cover the sinker at 10 -15 mm.
9.563 g F 0.925 g Wait until the weight display of the balance is stable. Actuating the PRINT – key will save the weight of the sinker in the sample liquid. The density of the liquid (ρ) is now automatically calculated and shown on the display [ g/cm3 ]. Data output to the serial interface RS 232. The result is issued in g/cm³. Remove sample; the measuring result still on display. Use the TARE -key to return to weighing mode.
5.2 Models KERN ALJ..N/ALS..N Procedure: − Press key . Pressing UNITS key, choose F7 d_Li. Ø − 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.
The volume of the float is noted into the balance memory. LoAd A and 0.000 appears on the display. Weight the float in air, hook it on the pan stand without beaker. − To note this value into the balance memory, press the PRINT key when result is stable. − LoAd L appears on the display – it is order to weight float in examined liquid. Take float off pan stand and set beaker with liquid on beaker stand. Adjust the amount of liquid in order float was immersed 10 - 15mm below the liquid surface.
− When the result is stable, press the PRINT key to note this value into the balance memory. − The result of liquid density is presented and kept on the display. − To avoid mistakes in measure units the letter F is before the result. Check if there are any air bubbles fastened to a float. It could cause errors during measurements. 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.
5.3 Model KERN ALT, PLT Key Display 20.02.05 P 8 01 02 03 04 05 06 07 08 Mode Parts Count Checkweighing Filling Percont Animal Density Formulation Statistics 20.02.
Parameter 02 sinker volume Enter the volume of the sinker (see embossment on suspension hook, information in cm³ e.g. 10.085 cm³): Density setup M6 01 Procedure 02 Sinker volume 03 Statistics 04 Run LIQUID DENSITY g/cm3 1.00000 OFF The current menu item is blinking Change the value of the number or Select the place to be changed, the active place is blinking or Density setup M6 01 Procedure 02 Sinker volume 03 Statistics 04 Run LIQUID DENSITY g/cm3 10 .0850 OFF Confirm your setting.
Determination of the weight sinker in air 27.3.05 Density W e ig h in g in t h e a ir. P la c e a s i n k e r [ E n te r ] 0 0% 0.0000 g 100% Wait until the stability and balancezero display shows. Suspend sinker from the centre, Measurement is carried out without beaker 27.3.05 0% 27.3.05 0% 38 Density W e ig h in g in t h e a ir. P la c e a s i n k e r [ E n te r ] 24.9617 g 100% Density W e ig h in g in a liq u id P la c e a s i n k e r [ E n te r ] 24.
Determination of the weight sinker in sample liquid 27.3.05 0% Density W e ig h in g in a liq u id P la c e a s i n k e r [ E n te r ] 0.0000 g 100% KERN ALT: Remove sinker, place beaker with sample liquid in the centre of the platform. Immerse sinker in the measuring liquid and suspend above from the suspension eyelet. The sample liquid should cover the sinker at 10 -15 mm. KERN PLT: 27.3.05 0% Density W e ig h in g in a liq u id P la c e a s i n k e r [ E n te r ] 14.8795 g 100% 27.3.
Remove sample or sinker, the measuring result is still on display. To start a new measuring cycle, press the UNIT-key. Data output to the serial interface RS 232. The result is issued in g/cm³. Return to weighing mode: 20.02.05 M0 M1 M2 M3 M4 M5 M6 Mode Basic weighing Parts counting Checkweighing Filling Percent Animal weighing Density Cursor (►) to „M0 Basic weighing“ Weighing 15.10.01 13:47:32 0.0000 Overview of display: 6 27.3.05 W 1=24 .9617 5 4 3 Density W 2=14 .8795 ...
6 Density table for water * The star indicates that the numeral to the left of the decimals is decreased by 1. Table from "Mass determination" by M. Kochsiek, M.
7 Recommendations • To form a reproducible mean value several density measurement are necessary • Remove fat from solvent-resistant sample /glass sinker /beaker. • Regularly clean sample dishes/glass sinker/beaker, do not touch immersed part with your hands • Dry sample/glass sinker/pincers after each measurement. • Adjust sample size to sample dish (ideal sample size > 5 g). • Only use distilled water.
