Efficient recycling of laminate waste, Remscheid
Meike Schulz, RHEWUM GmbH
The separation of particles whose size is sometimes difficult to assess with the naked eye can be a difficult screening task and requires precise technology. For a manufacturer of wooden floors, a RHEWUM screening machine is the solution to increase efficiency.
The laminate manufacturing process involves many steps. The biggest waste, however, occurs when the wooden boards are cut into planks. Both cut waste and sawdust are produced, which can hardly be sold as a final product. This was exactly the problem that RHEWUM's screening machines were used to deal with in 2016, when one of the global leaders in wooden flooring and interior design relied on RHEWUM to recycle its waste and thus increase the overall efficiency of its production. The special challenge here was the separation of the finest sawdust from a mill. In general, wood-based materials tend to clog the screen cloth easily. During the screening process, the fine particles can get stuck in the meshes and reduce the screening performance.
In this case, the customer's grain spectrum was broad. From easily visible wood chips with a size of more than 10.0 mm, which have to be crushed again, to the screening of fine dust below 400 microns, which accounts for almost one third of the total feed material. The visible wood chips are now crushed to a size between 0.4 mm and 10.0 mm. The fine dust below 0.4 mm is recovered to heat the furnace. Effectively none of the material has to be thrown away and is economically re-used.
Reliable screening technology
The cut waste and sawdust produced during production are an optimal task to combine the RHEWUM screen mesh types WA and WAU. Driven by an unbalance motor, the WAU principle is ideally suited for medium-size screen cuts such as the 10.0 mm screen cut used. The small drives have the power to transmit sufficient vibrations to the thicker wire diameter of such a net. The fine dust below 0.4 mm was processed with the electromagnetic drives of WA developed by RHEWUM itself. By means of a high-frequency beater bar movement, the material to be screened is discharged at right angles from the screen cloth - the inclination of the cloth enables the material to be screened to be transported over the screen. Tough electromagnets work outside the screen housing and transmit the vibrations to the screen fabric via vibrating axles. The electromagnets achieve accelerations of 15 g and more on the screen mesh. The RHEWUM screen fabric is excited to high-frequency vibrations by means of the beater bar movement.
The delivered screens measure a total of 2.2 meters and 6.0 meters length each. They process on two decks per screen a conveying capacity of 3 - 6 tons per hour for the aforementioned cut-offs of 10.0 millimetres and 0.4 millimetres. With a comparatively low bulk material of 0.23 kilograms per liter, this nets a total volume of more than 10 – 20 cubic meters per hour and per screen.
Unique brush cleaning
Especially for applications with difficult to screen materials RHEWUM is developing a brush cleaning system which supports the screening process. The brush is a further add-on to the cleaning cycle which keeps the screen surface open and thus maintains efficiency. It is a round brush which moves and rotates automatically along the screening surface in programmable cycles and can only be applicated on static screeners. If it is not needed, it folds up automatically in order not to block the valuable screen surface. In addition, this feature increases the efficiency and life expectancy of the machine, while reducing the hours required for manual cleaning.
When processing bulk materials, the efficient screening of various materials plays a decisive role. The selection of the right machine type and size requires a lot of experience and the possibility to adapt the machine characteristics to the desired product specifications. We are pleased to have worked with the customer to find an efficient and more environmentally friendly solution for their wood waste.
Would you also like individual advice on how to process your secondary raw materials more efficiently? Then please contact us to arrange a callback from our screening experts.