Mitsubishi Plastics Industries Limited

Haneda Humepipe Co., Ltd.

Sueo Yokota

A method of producing a lined Hume pipe wherein an inner surface of a Hume pipe having a large-diameter socket at one end thereof and a spigot at the other end is covered with a synthetic resin pipe. The method includes the steps of (1) inserting the synthetic resin pipe into the Hume pipe and fitting end caps with the projecting end portions of the synthetic resin pipe in such a manner that the socket and the spigot are closed by the end caps; (2) inducing a heating medium into the synthetic resin pipe so as to soften the same, inducing a pressurized fluid to expand the same until the synthetic resin pipe comes into almost tight contact with the inner surface of the Hume pipe, and ejecting the pressure fluid; (3) removing one of the end caps cutting away the projecting end portion, press-fitting a die into the end portion so as to make the synthetic resin pipe tightly contact with the inner surface of the socket; (4) closing the opposite end portions, inducing the heating medium again to soften the same, inducing the pressure fluid again until the outer surface of the synthetic resin pipe comes into complete contact with the inner surface of the Hume pipe, and ejecting the pressurized fluid and (5) heating to soften the end portion of the synthetic resin pipe and folding outwardly the projecting end portion to cover an end surface and an outer surface of the spigot of the Hume pipe.

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Nagahama, Japan

Sueo Yokota