Fields of application

Roll crushers are used for the crushing of medium-hard rock as
well as for sticky and soft materials, i.e. lignite and mineral coal,
clay, marl, limestone and similar raw materials.


Functioning

The feed material is crushed by shear- and tensile forces being
generated by high rotor torques at low circumferential speeds.
The individual crushing tools are arranged to allow fines in the
feed material to flow unrestrained between the crushing rolls -
similar to screening by roller screens. Because of that, the speci-
fic power requirement, the wear rate and the fines content in the
finished product are considerably lower than with other crushing
machines.


Roll crushers for primary, secondary and tertiary crushing

Depending on its design and application roll crushers achieve
crushing ratios ranging between 3:1 and 6:1. Different sizes with
throughput rates of up to 14,000 t/h are available. The roll crusher
is designed to accept lumps with edge lengths of up to 1,700 mm
for use in a primary function and of up to < 8 mm for use in a terti-
ary function.


Crushing tools

The type of crushing tool and fastening system employed depends
on the application. The crushing tools can be executed as crushing
ring, segments or picks thus ensuring an easy handling.


Drive

The crushing rolls are driven by two drive lines arranged on either
side of the housing. The drive unit can be designed as V-belt drive
or direct drive.


Hydraulic overload protection system

The hydraulic system consists of a hydraulic power unit and two
cylinders and is utilized for the adjustment of the crusher gap and
overload protection. The floating roll is moved manually with the
help of the hydraulic system and the crusher gap is adjusted with
shim plates. During automatic operation, a pre-pressure applied
by the hydraulic cylinders keeps the floating roll in its crushing
position. To protect the crusher from undue damage, the floating
roll retracts parallel in an overload situation thus relieving the sep-
aration forces and allowing the foreign object to pass.