A RISER CONNECTOR

摘要

A system for connecting and disconnecting a lower end of a marine riser (25) to and from a blow out preventer stack on a subsea wellhead comprises gripping members (26) for the marine riser and a lock element (27) for locking the gripping members (26). The system comprises first primary actuators (28), second primary actuators (29) and secondary actuators (30) for moving the lock element (27) to an unlock position, and hydraulic circuitry for actuating the actuators. The system further comprises a hydraulic backup unlock circuit (9, 11, 16) comprising a triple flow divider (8) for dividing fluid flow from a source (16) into one flow for actuating the first primary actuators (28), one flow for actuating the second primary actuators (29) and one flow for actuating the secondary actuators (30).