BELLOWS EXPANSION JOINT Russian patent published in 1997 - IPC

FIELD: erection of pipe lines. SUBSTANCE: bellows compensation joint includes two bellows pieces of smaller diameter and one bellows piece of larger diameter interconnected by means of spacers. Inner spacer is provided with centering ring fitted in outer spacer at guaranteed clearance and tubular piston. Centering ring has circular groove with fluoroplastic ring located in it. Flexible sealing member is mounted between outer spacer and tubular piston. Inner cavity of bellows of larger diameter is brought in communication with main; cavities between first and second bellows of smaller diameter and outer spacer are brought in communication with excessive pressure source. EFFECT: enhanced efficiency. 6 cl, 2 dwg