Joint for duplex pipes

A joint for connecting a first duplex pipe to a second duplex pipe, each of the first and second duplex pipes including an outer pipe for passing a first fluid, and an inner pipe disposed inside the outer pipe, the inner pipe for passing a second fluid, the joint comprising:

• a first outer pipe seal unit attached to an end of the outer pipe of the first duplex pipe;
• a second outer pipe seal unit attached to an end of the outer pipe of the second duplex pipe;
• a first inner pipe seal portion formed at an end of the inner pipe of the first duplex pipe;
• a second inner pipe seal portion formed at an end of the inner pipe of the second duplex pipe;
• a first sealing member disposed between the first outer pipe seal unit and the second outer pipe seal unit, the sealing member for sealing the outer pipes to prevent leakage of the first fluid;
• a second sealing member disposed between the first inner pipe seal portion and the second inner pipe seal portion, the sealing member for sealing the inner pipes to prevent leakage of the second fluid;
• and
• a connection structure for connecting the first and second duplex pipes, under a condition that the first sealing member is disposed between the first outer pipe seal unit and second outer pipe seal unit, and the second sealing member is disposed between the first inner pipe seal portion and the second inner pipe seal portion,
• wherein a clearance between the first outer pipe seal unit and the second outer pipe seal unit is defined larger than a clearance between the first inner seal portion and the second inner pipe seal portion.