Abstract: In the present invention, a pipe joint has housing parts as a housing obtained by dividing the housing into three parts in a circumferential direction. The first housing part has connecting parts. The second, third housing parts have connecting parts, respectively. Connecting parts are provided to be detachably mutually connected by fastening with tightening members, at end parts protruding outward from vicinities of an inner peripheral surface with a sealing member arranged in sides opposite to sides of the first housing part.

Abstract: In a water-hammer preventing unit for a check valve according to the present invention, a retainer pipe having openings at two edges thereof is provided inside a short pipe to form a circular space with the short pipe, and openings are formed on this retainer pipe. Further an elastic tube is provided on an external peripheral surface of the retainer pipe and covers the openings, and a communication path is formed between the short pipe and the valve body holder, and the communication path communicates the circular space to the flow path in the upstream side of the valve body and, when a fluid flows in the reverse direction, a portion of the fluid is accommodated from the opening into the circular space by expanding the elastic tube toward the circular space, and also flows a portion of the fluid in the said circular space to the flow path in the upstream side from the valve body.

Abstract: A pipe joint is made up of a hollow cylindrical joint body made of an elastic material with a prescribed length, a circular flange embedded into each of the ends of the joint body, through holes provided axially at prescribed intervals in the direction of the circumference of the flanges and the joint body, and both flanges connected to the joint body with a connecting appliance penetrating into these through holes.

Abstract: This pipe joint comprises a hollow cylindrical joint body made of elastic material such as heat-resistant rubber with a prescribed length, and a circular flange for connecting piping attached to the both sides of the joint body, on the side of the inner circumference of the joint body is provided a bellows metal pipe closely contacted with the joint body, and the thickness of the joint body is at least larger than the size of the summit or the trough of bellows of the metal pipe.