Patent ID: 8087424
Filing Date: 2012-01-03
Classification: F16K,Y10T

Abstract:
1. A subsea valve actuator apparatus for actuating a subsea valve, said valve actuator comprising: a housing defining an enclosure and a rim; said housing including: a cover cooperating with said rim for sealing said enclosure; a gearbox disposed within said enclosure; said gearbox including: a worm wheel connected to the subsea valve for actuating the valve; a seal disposed between said worm wheel and said housing for sealing said worm wheel relative to said housing so that lubricant disposed within said enclosure for lubricating said gearbox is sealed within said enclosure; a pressure compensator disposed within said enclosure for maintaining pressure of the lubricant disposed within said enclosure at substantially the same pressure as the pressure of seawater outside the gearbox; said pressure compensator including; a cylindrical wall having a first and a second end, said wall defining a chamber; a piston slidably disposed within said chamber, said piston having a first and a second end so that said piston separates said chamber into a first and a second cavity, said first cavity being disposed adjacent to said first end of said piston, said second cavity being disposed adjacent to said second end of said piston; said first cavity being in fluid communication with the seawater disposed outside the enclosure; and said second cavity being in fluid communication with the lubricant disposed within said enclosure so that a pressure differential between the pressure of seawater outside the enclosure and the pressure of the lubricant disposed within said enclosure slides said piston within said chamber such that said pressure differential of said first cavity relative to said second cavity is reduced to zero so that the pressure of the lubricant disposed within said enclosure is maintained at substantially the same pressure as the pressure of seawater outside said enclosure such that a pressure difference across said seal is minimized.