In recent years conventional roller screens proved more and more successfully as sturdy and effective organs for the screening of fines in the feed material of crushing plants.
On the roller screen the separation surface is formed by rotating disc-fitted rollers, which transport the material fed in, circulate and loosen it. The separation of the fines is effected in the gap between the individual rollers whilst the coarse material is transported via the screen into the overflow. The form of the discs as a polygon supports the material conveyance.
Especially in case of difficult to screen bulk material (moist material with loamy or argillaceous shares) this kind of screening appears to distinctly outclass the oscillating screening machines, which frequently show baking and adhesions with these materials. Adhesions due to the movement in the separation surface and the resulting self-cleaning properties do not occur at roller screens. In addition, each roll has scraper elements for a guaranteed cleaning.
Furthermore the downstream crusher is relieved through a roller screen which obviously results in a lesser wear, a reduced energy consumption and – at best – in using a smaller crusher. Hence in general roller screens entail reduced energy and operational costs and/or an increased operational safety.
Transporting the material is effected horizontally so that the subsequent crusher is fed gently and constantly.
The compact design, resulting from the horizontal material flow, as well as a multitude of options permit the application in many ranges – above as well as underground. Plants of this type are suited for different operations in limestone, clay, argil, coal, natural stone, salt, gypsum and other materials.
The HAZEMAG roller screen HRS is available as a one or multi-stage device as well as with a variable gap setting, thus meeting all customer requirements.
Due to a modularization of the roller screen length almost any sizes of separation surfaces may be realized.
The HAZEMAG VARIOwobbler® HVW constitutes the new generation of roller screens. Its distinctive feature is that the gap setting between the individual shafts and thus the separation is infinitely adjustable at the push of a button and without any tools.
This leads to a distinct extension of the field of application and a solid increase of flexibility by being able to very quickly respond to changing requirements and permitting a permanently correct adjustment of the roller screen.
The distance between the individual shafts is infinitely adjusted by a mechanic-hydraulic system. In the front part of the machine the roller distance is fixed in most cases at the smallest required gap, whilst the rear part is correspondingly adjustable. This permits to respond very flexibly to changing input, market and operational requirements.
Advantages of the VARIOwobbler®
- no adhesions or clogging in case of difficult to screen bulk materials
- vibration-free and low-noise operation
- gentle and continuous feeding of the downstream crusher
- suitable for thick-layer screening because the material is considerably better
- loosened and circulated
- low construction height