DANSK DSF/FPRCEN/TR 17838 PDF

Screw conveyors are mechanical devices for the continuous move, discharge or variable rate feeding of bulk materials in form of powder, granules or grain. They are often used horizontally or at a slight incline to discharge or feed silos, storage bins, cyclones, filter units, mills or other equipment in many bulk handling industries. This Technical Report describes requirements on screw conveyors which can in addition be used as explosion isolation systems to prevent a dust explosion transmission into connected plant items. The scope of this technical report is limited to rigid tubular screw conveyors which consist of a spiral blade coiled around a shaft held in external bearings (the rotating part of the conveyor is sometimes called “auger”). Additional internal bearings can be necessary if the tubular screw conveyor exceeds a certain length.