Screw special for polyvinyl chloride (PVC) cold bending tube extruder

The utility model relates to a screw, in particular to a screw special for a polyvinyl chloride (PVC) cold bending tube extruder. A plasticizing section is arranged on the screw, and a feed back chute is arranged on the screw edge of the plasticizing section. The length Z of the plasticizing section is from 130mm to 150mm, the width D of the feed back chute is from 20mm to 22mm, and the distance between the bottom of the feed back chute and the bottom of the screw edge is from 4mm to 5mm. The preferable length Z of the plasticizing section is 140mm, and the preferable width D of the feed back chute is 20mm. When tubes are produced by the screw special for the PVC cold bending tube extruder, even though materials are small, a part of materials can be sent back through the feed back chute and mixed with the next sent materials so as to achieve the purpose of being fully plasticized. The screw special for the PVC cold bending tube extruder can guarantee the load stability of a main motor and ensures the extruded