Efficient recycling of laminate waste
Rhewum screening machine as a solution for wood recycling
The manufacturing process of laminate includes many steps. However, the largest amount of waste is produced when the wooden boards are cut into planks. Both waste and sawdust are produced, which can hardly be sold as an end product. This was exactly the problem in 2016 when one of the world`s leading manufacturers of wooden flooring and interior fittings relied on RHEWUM screening machines to recycle its waste in order to increase the overall production efficiency. The special challenge here was the separation of the fine sawdust which comes from a mill. In general wood-based materials tend to clog the screen fabric easily. This is because 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 wide. From highly visible wood chips of more than 10.0 mm in size that have to be shredded again, to the screening of fine dust below 400 microns, which makes up almost a third of the total feed material. The visible wood chips are now shredded to a desired size between 0.4 mm and 10.0 mm. The fine dust below 0.4 mm is recovered to heat the kiln. This means that in future there will be no need to dispose of wood waste, as it will be economically reused.
The cutting waste and sawdust that accumulate during production is an optimal task for combining the Rhewum sieve mesh types WA and WAU. Driven by an unbalance motor, the WAU principle is best suited for medium separation cuts, such as the 10.0 mm separation cut used here. The small drives have the power to transmit sufficient vibrations to the thicker wire diameter of such a mesh. The fine dust below 0.4 mm was processed with the electromagnetic drives of WA, developed by RHEWUM themselves. By means of a high-frequency beater bar movement the screenings are thrown off the screen mesh at right angles - the inclination of the mesh allows the transport of the screenings over the screen. Outside the screen housing, robust electromagnets work, which transmit the vibrations into the screen cloth via vibrating axles. The electromagnets cause accelerations of 15 g and more on the screen fabric. By means of the beater bar movement the RHEWUM screen cloth is excited to high-frequency vibrations. In the constructed screening machine the total width of the screens was 2.2 m, the length 6.0 m. They process on two decks per screen a conveying capacity of 3 - 6 tons per hour for the mentioned separation cuts of 10.0 mm and 0.4 mm. With a comparatively low bulk material of 0.23 kilograms per litre, this results in a total volume of more than 10 - 20 cubic metres per hour and per screen.
Especially for such applications with difficult to screen materials RHEWUM developed a brush cleaning system which supports the screening process. It is a round brush which can only be used with static machine bodies. It is a further addition to the cleaning cycle which protects the screening surface from clogging and therefore maintains the efficiency. The brush moves and rotates automatically along the screen surface in programmable cycles. When it is not needed, it folds up automatically so as not to block the valuable screen surface. In addition to increasing efficiency, this additional feature reduces the number of hours required for manual cleaning as well as the life expectancy of the machine.
When processing bulk materials, efficient screening plays a decisive role. Choosing the right type and size of machine requires a lot of experience. We are pleased to have found a beneficial and more environmentally friendly solution for our customers` wood waste.
