Expansion mold, production line and method for producing PVC-O, BOPVC and biaxially oriented PVC pipes

Abstract

The invention discloses an expansion mold for producing PVC-O, BOPVC and biaxially oriented PVC pipes. The expansion mold comprises a guide section, pipe diameter expansion units and a fixed diameter section; the pipe diameter expansion units are of a cone structure, a small-diameter end of the pipe diameter expansion units is connected with the guide section, and first through holes are formed in the surfaces of the pipe diameter expanding units; the fixed diameter section is arranged at the rear end of the pipe diameter expanding units, and a second through hole is arranged on the fixed diameter section. According to the expansion mold, the pipe diameter expansion units can form a step-shaped pipe diameter expanding structure so that the product quality after expanding the diameter of the PVC-O pipe can be improved, and the operation difficulty of bidirectional stretching of the pipe can be greatly reduced; a plurality of the through holes are formed in the expansion units and the fixed diameter section, the pressure can be output outwards through the through holes in the expansion mold to counteract the retraction force of the tube itself so that a blank tube can pass through the mold in a small resistance state, the problem that the resistance between the blank tube and the mold is large can be greatly solved, and therefore the biaxially oriented operation difficulty of the PVC pipe is greatly reduced.

Description

technical field [0001] The present invention relates to the technical field of biaxial stretching equipment for PVC pipes, more specifically, to an expansion die for producing PVC-O, BOPVC, and biaxially stretched PVC pipes, and an expansion die for producing PVC-O, BOPVC, and biaxially stretched PVC A production line for pipes and a method for producing PVC-O, BOPVC, biaxially stretched PVC pipes. Background technique [0002] PVC-O pipe (BIAXIAL ORENTED PVC PIPE) is also called biaxially stretched PVC pipe. Because of its excellent pressure-bearing performance, economy and safety, it has been widely used in urban water supply and other fields in developed countries. It is a substitute for traditional PVC-U pipes, PE pipes, and ductile iron pipes in the water supply field. Countries such as Britain, France, the Netherlands, Portugal, the United States, Australia, South Africa and Japan have used it for many years, and the economic and social benefits are remarkable. Howe...

AI Technical Summary

Problems solved by technology

However, due to the difficulties in the manufacturing process, foreign technology secrecy and high cost of imported technology, China has not yet commercially produced oriented polyvinyl chloride (PVC-O) pipes on the market.

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