Hitachi Metals, Ltd.

Tokyo Gas Company Limited

Sanko Gas Seiki, Ltd.

Minoru Fujiyoshi

Fumitaka Satoh

Tomoyuki Minami

Tamaki Hamaguchi

Morio Saito

Shinichi Kanomata

Masahiro Mohri

Michio Hasegawa

Takashi Anamizu

The formation of a resin layer, a metal layer and an insulating resin layer on an outer surface of a corrugated metal pipe for flowing a fluid provides a flexible pipe, whose corrugated metal pipe does not suffer from having apertures even with spark discharge by induced lightning.

Flexible pipe

A pipe joint for connecting a flexible corrugated tube includes a joint body, a sleeve received in an axial through bore in the joint body for holding a free end of the flexible corrugated tube, and a nut threadedly fitted in a threaded portion of the joint body. A shoulder is formed on an inner surface of the through bore, and has an air-tight surface directed toward one end of the through bore. A tapering surface, decreasing in diameter progressively toward the shoulder, is formed on the inner surface of the through bore in adjacent relation to the shoulder. An annular groove of a generally channel-shaped cross-section is formed in the inner surface of the through bore in adjacent relation to the tapering surface. The sleeve has projections extending radially inwardly from one end thereof facing said shoulder, the sleeve having an end surface at the other end thereof. The projections are pivotally movable resiliently relative to the remainder of the sleeve so as to be received in a predetermined one of valleys in the outer peripheral surface of the corrugated tube. The nut has a holding portion for holding outer surfaces of the projections of the sleeve in registry with the annular groove. The nut has a flange surface for abutment against the end surface of the sleeve.

Pipe joint for connection of corrugated tube

Growing community of inventors

Mie-ken, Japan

Minoru Fujiyoshi