Mettler Toledo 33360 Mode D'emploi page 9

4. How to perform density determinations
Reminders:
- It is recommended to check the calibration.
- Along with the text below, please check the illustrated instructions which are enclosed with this description.
4.1 Determining the density of liquids
- Use displacement body 210260 + density determination kit for liquids 33360.
- Place empty beaker on bridge 4, centered below suspension 7; insert thermometer 8.
- Attach sinker 6. It must not touch the beaker or the thermometer.
- Tare balance to show exactly zero.
- Pour liquid to be tested into beaker up to about 10 mm above the eyelet of the sinker. No air bubbles should
adhere to the sinker. If necessary, brush off bubbles with a fine brush or the like.
- The balance displays (with minus sign in front) buoyancy P
must now be divided by 10. After that, add 0.001 g/ ml.
The result is density ρ
P
s
=
ρ
1
V
s
If the direct buoyancy indication is to be dispensed with, P
sinker in air; B = sinker in liquid. Procedure is the same as above, but the balance is tared before the sinker is
s
attached. With the sinker attached, the balance then indicates value A
indicates (without additional taring!) value B
Example with buoyancy indication: Determining the density of acetone.
Measured P = 7.898 g
s
values: T = 20 °C
The density of the acetone tested amounts to 0.7908 g/ ml at 20 °C.
METTLER TOLEDO 33360 + 210260
(g/ ml) at a given temperature T (to be read).
1
P [g]
s
+ L = + 0.001 g/ ml at T °C
s
10 ml
.
s
ρ
1
Arrangement
1 Weighing pan of METTLER TOLEDO balance
2 Bracket attached to weighing pan ...
3 ... clamping screws hold bracket in place
4 Bridge placed on balance housing across weighing pan.
Warning: Weighing pan 1 and bracket 2 must not brush
against bridge:
5 250 ml beaker placed on bridge
6 Sinker or gem holder ...
7 ... suspension; the sinker or gem holder should hang
freely in center of beaker without touching.
Please note: The first weighing is dry!
8 Thermometer
The listing of the various parts is repeated on page 33 (Parts
List)
of the sinker. Value P
s
can be obtained from two separate weighings: A
s
. After the liquid is filled in, the balance
s
7.898 g
+ 0.001 g/ ml = 0.7908 g/ ml at 20 °C
10 ml
displayed by the balance
s
(P = A - B )
s s s
=
s
7