... 3.Easy Installation 4.High efficiency 5.ISO9001:2008 LS Spiral Screw Conveyor/Elevator for food/ ... and light industry, food and food industry. LS screw conveyor mainly convey powder, granular and small-block materials ... screw, but won't move forward, it will form contragradation at the plot bearing so that the machine ... one year (except for fragile items) High Efficiency Coal Screw Conveyor Machine