Kern PLT-A01, ALT-A02 User guide

KERN & Sohn GmbH

Ziegelei 1

D-72336 Balingen

E-Mail: info@kern-sohn.com

Phone: +49-[0]7433- 9933-0

Internet: www.kern-sohn.com

Operating instructions

PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N

KERN ALT-A02 / PLT A01

Version 1.0

01/2013

Fax: +49-[0]7433-9933-149

Set for density determination for analytical and precision balances KERN ALT-B,PLT-A, PLT-F, ALS-A / ALJ-A,

ALT-A02/PLT-A01-BA-e-1310

PLJ-A, PLS-F / P LJ-F, PLE-N

KERN ALT-A02 / PLT A01

Contents:

1 INTRODUCTION ............................................................................................................................ 3

1.1 SCOPE OF DELIVERY ................................................................................................................. 4

2 PRINCIPLE OF DENSITY DETERMINATION ............................................................................... 5

2.1 INFLUENCING MAGNITUDES AND ERROR SOURCES ...................................................................... 6

3 HOW TO PREPARE THE WEIGHING BALANCE ........................................................................ 7

4 INSTALLING THE DENSITY DETERMINATION SET .................................................................. 8

5 DENSITY DETERMINATION OF SOLIDS ................................................................................... 10

5.1 BALANCES WITH GRAPHIC DISPLAY (KERN ALT-B, PLT-A, PLT-F) .......................................... 13

5.2 BALANCES WITH LCD DISPLAY (KERN ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N) 17

Version 1.0 01/2013

Operating instructions Set for density determination for analytical and precision balances KERN ALT-B,PLT-A, PLT-F, ALS-A / ALJ-A, PLS-A /

6 DETERMINING DENSITY OF LIQUIDS ...................................................................................... 20

6.1 BALANCES WITH GRAPHIC DISPLAY (KERN ALT-B, PLT-A, PLT-F) .......................................... 21

6.2 BALANCES WITH LCD DISPLAY (KERN ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N) 25

7 PRECONDITIONS FOR PRECISE MEASUREMENTS............................................................... 28

7.1 CALCULATION OF RESULTS ..................................................................................................... 28

7.2 INFLUENCE FACTORS FOR MEASUREMENT ERRORS ................................................................. 28

7.2.1 Air bubbles ....................................................................................................................... 28

7.2.2 Temperature .................................................................................................................... 28

7.2.3 Solid matter sample ......................................................................................................... 29

7.2.4 Liquids .............................................................................................................................. 29

7.2.5 Surface ............................................................................................................................. 29

7.3 GENERAL INFORMATION .......................................................................................................... 29

7.3.1 Density / Relative Density ................................................................................................ 29

7.3.2 Drift of Balance Display ................................................................................................... 29

8 DENSITY TABLE FOR LIQUIDS ................................................................................................. 30

9 USER INSTRUCTIONS ................................................................................................................ 31

2 ALT-A02/PLT-A01-BA-e-1310

1 Introduction

The density sets ALT-A02 and PLT-A01 differ in the support of the weighing plate. For the density set suitable for your balance, please refer to the following overview.

KERN ALT-A02 KERN PLT-A01 Set for density determinati o n for

analytical and precision balances d= 0.1 mg / 1 mg

KERN ALT-B / PLT-A / PLT-F, ALS-A / ALJ-A, PLS-A / PLJ-A, PLS-F / PLJ-F, PLE-N

• In order to guarantee a safe and trouble-free operation, please read carefully the operating instructions.

• These operating instructions only describe the operation of the density determinati on set . For further information on how to operate your balance please refer to the operating instructions supplied with each balance.

Set for density determinati o n for precision balances d= 10 mg

KERN PLT-A, PLT-F PLS-A / PLJ-A, PLS-F / PLJ-F

ALT-A02/PLT-A01-BA-e-1310 3

Thermometer

Sinker with storage box

Allen key

3.356g/cm3

1.1 Scope of delivery

 Check packaging and density determination set immediately when unpacking for

possible visible damage.

 Make sure that all parts are completely present.

Retainer of immersion basket Universal immersion basket for

floating and descending solid matter

∅ 70 mm, 95 mm high

Retainer for sinker Glass beaker for density

determination „solid matter“

Platform for glass container

∅ 55 mm, 150 mm high

Glass beaker for density determination „liquid“

4 ALT-A02/PLT-A01-BA-e-1310

ρ =

A-B

ρ =

m V

2 Principle of Density Determinat ion

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 frequentl y applied units include:

, , The application of this density determination set in combination with the KERN

ABS/ABJ balances provides fast and safe determination of solids and liquids. Our set uses the "Principle of Archimedes" to determine density:

BUOYANCY IS A FORCE. IT AFFECTS A BODY THAT IS IMMERSED INTO A LIQUID. THE BUOYANCY OF THE BODY EQUALS THE WEIGHT FORCE OF THE DISPLACED LIQUID. THE FORCE OF BUOYANCY ACTS VERTICALLY UPWARDS.

Thus, density is calculated according to the formulae below:

To determine the density 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 the sample in the aid liquid

= Density of the aid liquid

ALT-A02/PLT-A01-BA-e-1310 5

ρ =

A-B

Determining density of liquids

The density of a liquid 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 test liquid [ B ]. According to the Archimedes’ Principle a body immersed in a liquid experiences a force of buoyancy [ G ]. This force equals the weight force of the liquid displaced by the volume of the body. The volume [ V ] of the immersed body equals the volume of the displaced liquid.

G = buoyancy of sinker Buoyancy of sinker =

Weight of the sinker in air [ A ] - weight of sinker in test liquid [ B ] From this follows:

ρ = density of sample liquid A = weight of sinker in air B = weight of the sinkers in test liquid 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

= 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 or of the sinker  Porosity of the solid

6 ALT-A02/PLT-A01-BA-e-1310

3 How to prepare the weighing balance

When the density set is installed, correct adjustment is not possible. Perform necessary adjustment before installation of the density set using the

standard weighing plate. If the balance is equipped with an internal adjustment weight (ALT / PLT, ALJ-A,

PLJ-A, PLJ-F) carry out an internal adjustment. After adjustment, enable “external adjustment” in the adjus tme nt mo de me nu. This will avoid a request of an internal adjustment, when the density set is installed.

If the balance is equipped with an external adjustment weight (ALS-A, PLS-A, PLS- F, PLE-N) carry out an external adjustment.

For carrying out please refer to the operating instructions supplied with each balance

ALT-A02/PLT-A01-BA-e-1310 7

weighing plate.

4 Installing the density determin ation 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

 Disconnect scale fr om power supply.  Remove the standard weighing plate acc. to fig.

Models ALT, ALS/ALJ Models PLE, PLS/PLJ, PLT; d = 0.1 mg - 1 mg

Models PLS/PLJ, PLT; d = 10 mg

8 ALT-A02/PLT-A01-BA-e-1310

Installed density set for solid matter „precision balances“

d= 10 mg

d = 0.1 mg - 1 mg

 Install density determination set

(for solid matter please see chap. 5, for liquids see chap. 6)

Installed density set for solid matter “analytical balances”

ALT-A02/PLT-A01-BA-e-1310 9

5 Density determination of solids

For the determination of the density of solids, the solid is first weighed in air and then in the aid liquid, whose density is known. From the weight difference results the buoyancy from where the software calculates the density. As aid liquid, usually distilled water or ethanol is used, see density table chapter 8.

Prepare balance as described in chapter 3 "Installation of density determination set".

 Place the retainer of the immersion basket on the cone of the weighing plate.  Place the platform for glass containers in a way that it does not touch the

retainer of the immersion basket.

 Place beaker in the centre of the platform Make sure that it has no contact with

the retainer or with the immersion basket.

 Hang the immersion basket on the retainer. Make sure that it is centred in the

recess.

 Fill the aid liquid into a glass beaker. Fill in so much liquid that the solid matter

after immersion remains at least 1 cm under the liquid level. Immerse thermometer

 Bring aid liquid / instruments / sample to the right temperature until you

achieve a constant temperature. Observe the warm-up time of the balance.

 Connect balance to power supply, the balance will carry out a self-test. Switch

on using the ON/OFF button and wait until the gram display appears.

10 ALT-A02/PLT-A01-BA-e-1310

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