Patent ID: 8857175
Filing Date: 2014-10-14
Classification: E21B,F15B

Abstract:
1. A two-stage actuator adapted to be submerged in a liquid to provide a source of power without any umbilical power connection to the surface of said liquid for operating a submerged actuator on a blow-out preventer, comprising: a first cylinder; an intensifier piston mounted in said first cylinder for sealed sliding movement therealong; said intensifier piston having a large-area surface which, in use, is continuously exposed to the pressure of said liquid at the depth at which said actuator is submerged, and having a small-area surface; a second cylinder having an end wall; an actuator piston mounted in said second cylinder for sealed sliding movement therealong; an actuator rod connected to said actuator piston for movement therewith and having an intermediate portion sealingly penetrating said second cylinder end wall; said actuator piston having a large-area surface and a small-area surface; an intermediate chamber communicating said intensifier piston small-area surface with said actuator piston large-area surface; and an incompressible fluid in said chamber; whereby the pressure of said liquid at the depth to which said actuator is submerged in use creates pressure in said intermediate chamber for urging said actuator piston to move toward said second cylinder end wall for operating said actuator on said blow-out preventer.