Polyethylene corrugated pipe and expansion molding process thereof

Abstract

The invention discloses a polyethylene corrugated pipe and an expansion molding process thereof, and relates to the field of plastic pipeline molding methods. According to key points of the technicalscheme, the expansion molding process includes the following steps that S1, the corrugated pipe is fed onto an expansion mold; S2, the flaring end is heated by an annular far-infrared heating part; S3, heating does not exceed the critical temperature of melting, and after softening, the end needing to be expanded is flared through the expansion mould; S4, cooling molding is conducted; S5, air is fed into the inner wall of the pipe through an air blowing system in a contact adsorption state; and S6, demolding is conducted. The polyethylene corrugated pipe and the expansion molding process thereof have the technical effects that 1, the annular far-infrared heating part is used for heating, heating equipment with glycerin used as a heating medium is avoided, and thus the situations that the glycerin is mixed with water inevitably, the decomposition temperature of the glycerin is lowered, and a large amount of smoke is produced to pollute the environment are avoided; and 2, by changing theheating form and controlling the temperature difference, the axial shrinkage ratio of the corrugated pipe is well controlled, use of the large heating equipment is avoided, and 50% of electricity issaved compared with the large heating equipment.

Description

technical field [0001] The invention relates to the field of molding methods for plastic pipes, in particular to an expansion molding process for polyethylene corrugated pipes. Background technique [0002] The tubing is easily uniaxially (ie, axially) stretched orientated during the forming process. This orientation can be achieved simply by increasing the speed ratio of pipe pulling and extrusion. However, this axial stretch orientation is meaningless to the performance of the pipe, because although it increases the strength of the pipe in the axial direction through stretch orientation, it reduces the radial, that is, the hoop strength of the pipe. [0003] This is very harmful to plastic pipes, especially water supply pipes. Because it will reduce the hydraulic burst strength of the pipe. This is also the reason why in the quality standard of the pipe, it is stipulated that the longitudinal retraction rate of the pipe must be less than or equal to 5%. Ideal stretch o...

AI Technical Summary

Problems solved by technology

[0005] To sum up, when the pipe is flaring, the radial direction of the pipe is increased, and the proportional flaring of the pipe becomes difficult. If the wall thickness of the pipe is reduced, the hoop strength at the pipe flaring will be reduced, which improves the The tightness of the interface, but the original hydraulic burst strength of the pipe cannot be maintained

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