FRITSCH PULVERISETTE 1, Model I classic line - Manual (Page 22)

Page 20
crushing chamber
5.3 Crushing of material
5.3.1 Setting the jaw gap
The opening of the gap between the crusher plates determines the average grain
size of the crushed material. With the indexing cranked handles (7) the opening gap
can be selected by steps between about 1 mm and 15 mm. (In the lowest position
the gap is the smallest).
To select a different gap, pull out the knurled knob of the indexing cranked handles
(7) and insert the indexing cranked handles into the desired position. The indexing
cranked handles is fixed when the knurled knob snaps in.
Difficult to crush material (i. e. metal alloys) should first be pre-crushed at a larger
gap opening before the final gap setting is selected for a second pass.
If no experience is available regarding the fragility of your material, you should
break a test piece carefully in a first stage.
5.3.2 Introducing the material to be crushed
Larger pieces of material
• model I max. edge length 60 mm,
• model II max. edge length 95 mm
should be introduced piece by piece into the funnel.
A new piece of material should not be introduced before the crushing noise has
distinctly decreased.
You should never introduce more material to be
crushed than the volume of the crushing
chamber can accept. The crushing chamber is
limited by the upper edge of the lateral support
walls (13) and the crushing plates (18, 22).
No material to be crushed should be placed
above that limit.
Also when working on a continuous basis, no
more material to be crushed must be added than
crushed material comes out of the crushing gap.
The feed rate depends on the crushing behaviour of the material. For each new
material observe the crushing (crushing noise) and determine the optimum amount
of material.
5.3.3 Dust exhaust
When crushing certain materials (e.g. coal, boulders, stones) dust can be
generated that collects in the crushing chamber. In order to prevent this spreading,
the laboratory jaw crusher can be equipped with a vacuum. See chapter 6.1.
TIP
The instrument must be switched-on/running before
filling material into the funnel.