Patent ID: 7530602

Claim:
A double-pipe joint in combination with an inner and outer pipe structure which only passes fluid through said inner pipe and wherein: said double-pipe joint has an inner joint portion and an outer joint portion, said inner joint portion having: an inner-pipe receiving port for receiving an inner-pipe end portion of an inner-pipe joint body in an inward fitting state; a cylindrical inner-pipe sleeve which is to be pressingly inserted and fitted into said inner-pipe end portion; an inner-pipe union nut which is to be fitted onto said inner-pipe end portion, and which is screwable with said inner-pipe receiving port; an inner-pipe sealing face which is formed in said inner-pipe receiving port; and an inner-pipe sealing portion which is formed by pressing said inner-pipe end portion from an outer side by fastening due to screw advancement of said inner-pipe union nut toward said inner-pipe receiving port, and causing by the pressing function said inner-pipe end portion and said inner-pipe sealing face to be in close contact with each other, said inner joint portion connecting and coupling said inner pipe of a double pipe to said inner-pipe joint body, said double pipe comprising said outer pipe which is made of a synthetic resin, and said inner pipe which is disposed inside said outer pipe, and which is made of a synthetic resin; and said outer joint portion having: an outer-pipe receiving port for receiving an outer-pipe end portion in an outer-pipe joint body in an inward fitting state; a cylindrical outer-pipe sleeve which is pressingly inserted and fitted into said outer-pipe end portion; an outer-pipe union nut which is screwable with said outer-pipe receiving port while being fitted onto said outer-pipe end portion; an outer-pipe sealing face which is formed in said outer-pipe receiving port; and said outer joint portion connecting and coupling said outer pipe to said outer-pipe joint body with which said inner-pipe union nut is formed integrally.