Mechanism laying pipe on sea-bed under constant pipe tension - has pipe feed chains with support bogies pressurised via plates by air bags

摘要

Mechanism for maintaining constant mechanical longitudinal tension in a pipeline whilst this is laid on the seabed, comprises an upper and lower unit contg. respective pairs of driven parallel endless chains, each pair carrying V-shaped transverse bridge members with two rubber blocks per member to grip the pipe perimeter. Each unit comprises a frame, the upper frame being vertically adjustable relative to the lower to accommodate different pipe dias. (e.g. 8"-44"). Each frame comprises bogie sets with rollers paris to support the respective chains. The bogie sets are mounted on flexible plates each supported by a number of pneumatic elements (air bags) adjacent the respective sets which maintain constant radial force on the pipe. Control systems are provided to control the pipe feed rate such that a constant tensile stress is maintained. Used in laying pipeline from vessel on to seabed.