Optimal size reduction with roller crushers by Händle

»1 Händle-WMM 628f

In materials preparation, roller crushers are responsible for the “rough stuff“. They are optimally suited for the primary size reduction of soft or hard, moist or dry clods of clay with or without rock inclusions exhibiting Mohs hardness levels up to 6. Roller crushers render cloddy raw materials meterable and prepare them for effective further processing in downstream equipment. Size reduction is achieved by application of pressure and shear forces between two slowly rotating rollers, which may or may not be equipped with one-piece toothed disks or individually replaceable knives. The choice of crushing elements depends on the nature of the mill feed and on the targeted grain size. It is important that the knives or teeth be properly arranged in a spiral pattern, hence reducing the number of knives/teeth in simultaneous engagement, so the mill feed is moved around more over the rollers during comminution. This also avoids overloading and requires less power. The size-reduction ratio is easily adjusted by altering the roller gap anywhere between approx. 5 mm to 100 mm.

Händle makes two basic types of roller crushers: WMH with hydraulic drive and WMM with mechanical drive. The WMM models have advanced drives with modern conical spur gears and flanged-on motors. An interposed clutch that separates motor and gearing in case of an overload ensures very good operational safety and reliability. This also makes the drive assembly much more compact than before, with its previously employed type of coupling and belt drive. For raw materials containing substantial amounts of hard rock inclusions, reverse mode is recommended, and hydraulic crushers are particularly good at that. As soon as a certain, preset torque is exceeded, both rollers automatically go into reverse. The rock causing the overload is forced into a different position, making it easier to split and crush. The mechanical roller crushers can also be designed for reverse-mode operation. All they need is a variable-frequency motor. The standard version needs no such motor, because roller crushers are normally operated at a constant speed of rotation.

The size of the crusher depends on the throughput and on the nature of the mill feed. Each crusher comes mounted on a base frame for easy installation. A number of options are available for optimal customerization.