Patent ID: 7137652

Claim:
A pipe joint structure comprising: a vessel provided at an outer circumference with a first flat surface and at a circumferential wall with a through-hole having one end opened to the first flat surface and another end opened to an interior of the vessel; a joint fitting member having an interior insertion hole diameter larger than the diameter of the through-hole and a first screw thread at an inner circumferential wall or an outer circumferential wall, the joint fitting member being bonded to the vessel so that the first flat surface is positioned radially inside the insertion hole and surrounds an entire outer periphery of the through-hole opened to the first flat surface; a joint member provided with an insertion portion having (a) a second flat surface formed at an end, (b) a pipe connection portion having a conical pressure receiving seat formed at another end, and (c) a pipe mounting screw thread at an outer circumference, the insertion portion and the pipe connection portion being connected by an internal fluid passage with one end opened in the second flat surface and another end opened to the conical pressure receiving seat; a distribution pipe provided at an end thereof with a conical portion; and a mounting nut fastened into the pipe mounting screw thread so that the conical portion is pressed against the conical pressure receiving seat, wherein the joint member is further provided at a position inside the inner circumferential wall of the insertion hole or a position outside the outer circumferential wall of the joint fitting member with a second screw thread screwed with the first screw thread so that the insertion portion is inserted into the insertion hole so that the second flat surface is pressed against and in fluid tight contact with the first flat surface while the fluid passage communicates with the through-hole.