US Patent 8342202 Pipe coupling member for high-pressure fluid

A pipe coupling member for high-pressure fluid such as liquefied hydrogen includes a seal ring having a highly effective sealing function to prevent leakage of the fluid. The seal ring (72) is set in a seal ring setting space (39) defined by a second radial surface (36) and a seal ring setting surface (38) of a first tubular member (20), a forward end surface of a second tubular member (22), and the outer peripheral surface of a valve seat member (24). A forward end portion of the second tubular member (22) is provided with a communication hole (84) radially penetrating the forward end portion. The pressure of the high-pressure fluid on the downstream side of a valve seat surface (52) causes a fluid path in the second tubular member to be communicated with the sealing ring setting space (39) via the communication hole (84) and via a gap between the seal ring setting surface (38) and the outer peripheral surface of the forward end portion of the second tubular member.