rotary backflush Patt filtration continuous rotary ROTARY BACKFLUSH A ribbon type screenchanger also requires a specific screen which costs double or even triple that of the rotary backflush screens. The savings on screen costs with a rotary backflush system are substantial especially when using a high percentage of regrind or recycled material. Leakage is a problem with most screenchangers. In use they are usually torqued up to prevent leaks and then backed off when a screen change is needed. Rotary backflush screenchangers have a huge sealing surface and leakage is not a common problem. The body blocks and the faces of the disc are superbly machined and polished to mirror like finishes. Using very precise torquing techniques, manufacturers squeeze the disc to unbelievable values.