Joint for high-pressure pipes and joint structure

A pipe joint for high pressure pipes for connecting a first pipe and a second pipe to be used for a pressure equal to or higher than 14.7 MPa, said pipe joint comprising:

• a first joint to be connected to a first pipe;
• a second joint to be connected to a second pipe;
• a clamp having a band portion for covering a butting portion, an edge portion of the first joint and an edge portion of the second joint being opposed to each other with a gap, for connecting the first joint and the second joint under a butted state;
• a seal ring made of a metal material for maintaining a seal efficiency at a butting portion and being abutted to a part of edge portions on both sides;
• a tightening member for contracting an inner diameter of the band portion by a tightening operation;
• each of the first joint and the second joint having a pipe joining portion to be screwed to a pipe end portion, an intermediate portion having a fixed pipe thickness and an end portion having an outer diameter larger than the diameter of the intermediate portion, each being formed in order toward a butting portion, and a plate shaped recess to be abutted against a seal ring being formed at the center of an end surface at the end portion of the joint;
• and
• an outer diameter of each end of the first joint and the second joint at a butting portion being larger than an outer diameter of the middle portions of the first joint and the second joint, and an inner surface of the band portion being formed for the inner surface of the band portion at the clamp and each end portion of the first joint and the second joint becoming fitted under a butting state of the first joint and the second joint.

A pipe joint for high pressure pipes for connecting a first pipe and a second pipe to be used for a pressure equal to or higher than 14.7 MPa, said pipe joint comprising:

• a first joint to be connected to a first pipe;
• a second joint to be connected to a second pipe;
• a third joint having one end portion to be butted against the first joint and another end portion to be butted against the second joint;
• a first clamp having a band portion for covering a butting portion, an edge portion of the first joint and an edge portion of the third joint being opposed to each other with a gap, for connecting the first joint and the third joint under a butting state;
• a second clamp having a band portion for covering a butting portion, an edge portion of the second joint and an edge portion of the third joint being opposed to each other with a gap, for connecting the second joint and the third joint under a butting state;
• a seal ring made of a metal material for maintaining seal efficiency at a butting portion and being abutted against a part of an edge portion on both sides;
• a tightening member for contracting an inner diameter of a band portion by a tightening operation;
• each of the first joint and the second joint having a pipe joining portion to be screwed to a pipe end portion, an intermediate portion having a fixed pipe thickness and an end portion having an outer diameter larger than a diameter of the intermediate portion, each being formed in order toward the butting portion, and a plate shaped recess to be abutted against a seal ring being formed at the center of an end surface at an end portion of the joint;
• the third joint having an intermediate portion with a fixed pipe thickness and an end portion having an outer diameter larger than the outer diameter of the intermediate portion at both end portions of the joint, each being formed in order toward the butting portion, and a plate shaped recess to be abutted against a seal ring being formed at the center of an end surface at an end portion of the joint;
• the outer diameter of each end portion of the first joint and the third joint at the butting portion of the first joint and the third joint being larger than the outer diameter of the intermediate portion of the first joint and the third joint, and an inner surface of the first band portion being formed for the inner surface of the first band portion at the first clamp and each end portion of the first joint and the third joint to be fitted under a butting state of the first joint and the third joint;
• and
• the outer diameter of each end portion of the second joint and the third joint at the butting portion of the second joint and the third joint being larger than the outer diameter of the intermediate portion of the second joint and the third joint, and an inner surface of the second band portion being formed for the inner surface of the second band portion at the second clamp and each end portion of the second joint and the third joint to be fitted under a butting state of the second joint and the third joint.

A pipe joint for high pressure pipes for connecting a first pipe, a second pipe and a third pipe to be used for a pressure equal to or higher than 14.7 MPa, said pipe joint comprising:

• a first joint to be connected to a first pipe;
• a second joint to be connected to a second pipe;
• a third joint to be connected to a third pipe;
• a fourth joint having a first end portion to be butted against the first joint, a second end portion to be butted against the second joint and a third end portion to be butted against the third joint;
• a first clamp having a first band portion for covering a butting portion of the end portion of the first joint and the first end portion of the fourth joint with a gap, and for connecting the first joint and the fourth joint in a butted state;
• a second clamp having a second band portion for covering a butting portion of the end portion of the second joint and the second end portion of the fourth joint with a gap, and for connecting the second joint and the fourth joint in a butted state;
• a third clamp having a third band portion for covering a butting portion of the end portion of the third joint and the third end portion of the fourth joint with a gap, and for connecting the third joint and the fourth joint in a butted state;
• a seal ring made of a metal material for maintaining seal efficiency at a butting portion and being abutted against a part of an edge portion on both sides;
• a tightening member for contracting an inner diameter of a band portion by a tightening operation;
• each of the first joint, the second joint and the third joint having a pipe joining portion to be screwed to a pipe end portion, an intermediate portion having a fixed pipe thickness and an end portion having an outer diameter larger than a diameter of the intermediate portion, each being formed in order toward the butting portion, and a plate shaped recess abutting against a seal ring being formed at the center of an end surface at the end portion of the joint;
• and
• the fourth joint, at all the end of the joint, having an intermediate portion with a constant pipe thickness, an end portion having an outer diameter larger than the outer diameter of the intermediate portion being formed in order toward the butting portion, and further a plate like recess to be abutted against a seal ring being formed at the center of the end surface of the end portion of the joint, the outer diameter of each end portion of the first joint and the fourth joint at the butting portion of the first joint and the fourth joint being larger than the outer diameter of the intermediate portion of the first joint and the fourth joint and an inner surface of the first band being formed for the internal surface of the first band portion of the first clamp and each end portion of the first joint and the fourth joint to be fitted in the butting state of the first joint and the fourth joint;
• the outer diameter of each end portion of the second joint and the fourth joint at the butting portion of the second joint and the fourth joint being larger than the outer diameter of the intermediate portion of the second joint and the fourth joint, and the inner surface of the second band being formed for the internal surface of the band portion of the second clamp and each end portion of the second joint and the fourth joint to be fitted in the butting state of the second joint and the fourth joint;
• the outer diameter of each end portion of the third joint and the fourth joint at the abutting portion of the third joint and the fourth joint being larger than the outer diameter of the intermediate portion of the third joint and the fourth joint and an inner surface of the third band being formed for the inner surface of the band portion of the third clamp and each end portion of the third joint and the fourth joint to be fitted in the abutting state of the third joint and the fourth joint.

A joint for high pressure pipes for connecting N (larger than 3) pipes for a pressure equal to or higher than 14.7 MPa, said pipe joint comprising:

• N sub joints to be connected to each pipe;
• a main joint having N end portions to be butted against sub joints;
• N clamps having a band portion for covering a butting portion of an end portion of the sub joint and an end portion of the main joint being opposed to each other with a gap, for connecting a sub joint and a main joint in a butting state;
• a seal ring made of a metal material for maintaining seal efficiency at an abutted part and being abutted against a part of the end portions on both sides;
• a tightening member for contracting an inner diameter of a band portion by a tightening operation;
• the sub joint having a pipe joining portion to be screwed to a pipe end portion, an intermediate portion having a fixed pipe thickness and an end portion having an outer diameter larger than the outer diameter of the intermediate portion at the both end portion of the joint, each being formed in order toward the butting portion, and a plate shaped recess to be abutted against a seal ring being formed at the center of an end surface at the end portion of the joint;
• the main joint with intermediate portions having a fixed pipe thickness and end portions having an outer diameter larger than the outer diameter of the intermediate portion being formed in order toward the butting portion at N ends of the joints, in addition, a plate shaped recess to be abutted against a seal ring being formed at the center of an end surface at the end portion of the joint;
• and
• the outer diameter of each end portion of the sub joint and the main joint at the butted portion of the sub joint and the main joint being larger than the outer diameter of the intermediate portion of the sub joint and the main joint and the inner surface of the band portion being formed for the inner surface of the band portion at a clamp and each end portion of the sub joint and the main joint to be fitted under an butting state of the sub joint and the main joint.