Patent ID: 7347224

Claim:
A supply and exhaust pipe, comprising: a receptacle formed at one end of said pipe for connecting another pipe; and an insert portion formed at the other end of said pipe for being inserted into a receptacle of another pipe, wherein a bead for an O-ring is formed on the internal surface of said receptacle; a modified O-ring inserted in the bead for O-ring, the modified O-ring comprising a cap and a neck presenting a cross-sectional mushroom shape, during insertion of an insert portion into a receptacle, the modified O-ring has a neck pushed by an external surface of the insert portion and has a cap inclined within the bead for the O-ring to the opposite direction from the insert direction, and the cap contacts closely to the internal surface of the bead for the O-ring, and by contacting closely to the external surface of the insert portion with part of the circumference of the cap, the modified O-ring is intended to increase sealing efficiency at the joint when being connected with a design to establish close contacts to the external surface of the insert portion at two points including an edge of the neck and the cap, and to maintain sealing efficiency with a design to follow a bending when it is formed on the joint.