Vertical wave motion compensator - for ship-board derrick e.g. in off-shore oil well operations

摘要

System for compensating for the rise and fall due to wave motion of lifting tackle installed on a ship, partic. in the course of drilling or maintaining an off-shore oil well, of the known type having an oleo-pneumatic circuit forming an elastically deformable device, with at least one suspending hydraulic actuator in which the liq. pressure is generated by the wt. of the load carried on the lifting hook and is transmitted to a gaseous fluid accumulator forming a buffer, but more esp. also comprising, an auxiliary correcting actuator in parallel with the suspension actuator and controlled by a hydro-electric control circuit which is capable of generating a correcting force in the correcting actuator, in response to the rise and fall of the ship, opposing at any instant such rise and fall so as to eliminate all alternative motion of the load caused by this.