Automatic stainless steel bar screen mechanical sieves for wastewater pre-treatment The high efficient bar screen for wastewater treatment is installed at the inlet of pump station or water treatment system. It is composed of pedestal, specific plough shaped tines,rake plate, elevator chain and motor reducer units etc. It is assembled into different space according to different flow rate or channel width.The rake plate ,which is fixed in the elevator chain,starts clockwise movement under the drive of the driving device, hooking residue from down to up together with the elevator chain. Under the effect of steering guide and guiding wheel, residue gets discharged by gravity while the rake plate reached the top of bar screen. The rake tines moved to the bottom of the equipment and starts to work for another round, residue moves continuously.