Retsch AS 200 tap 30.025.1001 - Manual (Page 18)

8 January 2008 Retsch GmbH
18
Doc. no. D 98.025.9999
Working Instructions
Sieving aids
For materials that are difficult to separate we recommend the
additional use of sieving aids in the individual sieve fractions. For
this purpose and depending on the mesh size of the sieve and the
preselected oscillation intensity, balls of agate, rubber, porcelain or
nylon brushes and Vulkollan® cubes can be used. See also the table
below.
Make sure that the sieve mesh is not stretched excessively by
overloading with sieving aids, as this would impair the precision
of your analytical sieves.
For recommendations with regard to quantities of material
to be sieved, see the section on “Sieving Quantities”
Overview Table
Sieving aids Quantity per
sieve or sieved
material
Supplier Field of application Caution !!
Vulkollan® cubes 5 pcs., 12x12 RETSCH, Haan when planar sieve
machines are used
Brushes 3 pcs. RETSCH, Haan
Plastic rings 3 pcs., various
diameters
Small brushes with manual sieving
Highly dispersed silicic acid
(Aerosil) 0.5 to 2% Degussa,
Frankfurt on
Main with fine, sticky sieve
materials that contain
fat and are
electrostatically charged Before adding, check usability and
compatibility!
- - Aluminium oxide 0.5 to 1% Degussa,
Frankfurt on
Main
- - Talcum with crude rubber and
rubber powder
Drying with very wet/very
humid sieve materials
Pass dry warm air through the
set of sieves with hygroscopic sieve
materials
TAP function for fine materials that
stick easily and fall
through the machine
with difficulty A TAP function is built into the AS 200
tap tapping sieve machine and can be
switched off at will.
Quantities of material to be sieved
The stack of sieves required for sieve analysis is made up
of a number of analytical sieves arranged one on top of
the other in ascending order of hole width.
To ensure quick fractioning with an exact result, the
quantity of material to be sieved must be adapted to the
sieve diameter and the nominal diameter of the openings.
Guide levels for this are given in the respective standard
specifications for sieve analysis, e.g. according to DIN
22019/1 the following maximum added quantities are
recommended:
Nominal diameter of
sieve openings
Material quantities in dm3 for
diameters of 200mm
8 0 . 5 0 0
3 . 1 5 0 . 3 0 0
1 0 . 1 4 0
0 . 5 0 . 1 0 0
0 . 2 0 . 0 6 0
0 . 0 6 3 0 . 0 3 5
0 . 0 2 0 0 . 0 2 0