METHOD AND APPARATUS FOR CONTINUOUSLY PRODUCING DOUBLE-WALL PIPE HAVING PIPE SOCKET

摘要

PROBLEM TO BE SOLVED: To form an inside pipe and an outside pipe so as to have desired wall thicknesses respectively during the production of a pipe socket. SOLUTION: This apparatus is provided with two extruders extruding an outside pipe 37 and an inside pipe 39 through a joining crosshead 8 in order to continuously produce a double wall pipe consisting of a smooth inside pipe and the outside pipe having lateral grooves provided thereto and having a pipe socket. Switches 50, 51, 56, 57 are provided in order to produce the pipe socket 41 and, by these switches, the speeds of the extruders are corrected so as to reduce the mass flow of a molten plastic material for producing the outside pipe 37 during the production of the pipe socket 41 or to increase the mass flow for producing the inside pipe 39.