Continuous production of plastic pipe with bell end - by extruding cutting and then forcing onto bell forming die

摘要

Plastic (e.g. PVC) tubes with a bell end are formed by extruding a continuous tube from an extruder and feeding it through a thickness gauge and an external calibrating gauge. The tube is cut by a cutter and the cut length of tube advanced by a feed device onto an e.g. conical die mechanism to form a bell end on the cut length of tube. Dependent on the material being extruded the thickness gauge is used to control the extrusion rate and therefore the thickness of the pipe to ensure correct formation of the bell end. The pipes can be easily joined by telescopically engaging a plane end of one pipe into the bell end of another pipe. Continuous prodn. of pipes with a bell end is achieved.