Patent ID: 7934561

Claim:
A depth compensated subsea passive heave compensator comprising: a first cylinder having an upper end and a lower end; connector means mounted at the upper end of the first cylinder for connecting the first cylinder to a vessel at the sea surface; a first piston located within the first cylinder for reciprocation with respect thereto; a first piston rod connected to the first piston and extending downwardly therefrom through the lower end of the cylinder; connector means for securing the first piston rod to subsea equipment located beneath the first cylinder; a quantity of high pressure oil contained within the first cylinder between the first piston and the lower end of the first cylinder; a second cylinder having an upper end and a lower end; a second piston located within the second cylinder for reciprocation with respect thereto; a quantity of high pressure gas located within the second cylinder between the upper end thereof and the second piston; a quantity of high-pressure oil located in the second cylinder between the lower end thereof and the second piston; conduit means operably connecting the lower end of the first cylinder to the lower end of the second cylinder; a third cylinder having an upper end and a lower end; a third piston mounted within the third cylinder for the reciprocation with respect thereto; a quantity of low pressure oil contained with the third cylinder between the upper end thereof and the third piston; conduit means operably connecting the upper end of the third piston and the upper end of the first piston; a quantity of low pressure gas contained within the third cylinder between the lower end thereof and the third piston; and a second piston rod connected to the third piston and extending downwardly therefrom through the lower end thereof for applying the pressure of the sea to the third piston.