Abstract: A subsea valve actuator apparatus is disclosed for actuating a subsea valve. The valve actuator apparatus includes a housing which defines an enclosure and a rim. A cover cooperates with the rim for sealing the enclosure. A gearbox is disposed within the enclosure the gearbox including a worm wheel which is connected to the subsea valve for actuating the valve. The gearbox includes a seal which is disposed between the worm wheel and the housing for sealing the worm wheel relative to the housing so that lubricant disposed within the enclosure for lubricating the gearbox is sealed within the enclosure. A pressure compensator is disposed within the enclosure for maintaining pressure of the lubricant disposed within the enclosure at substantially the same pressure as the pressure of seawater outside the gearbox.

Abstract: A subsea valve actuator apparatus is disclosed for actuating a subsea valve. The valve actuator apparatus includes a housing which defines an enclosure and a rim. A cover cooperates with the rim for sealing the enclosure. A gearbox is disposed within the enclosure the gearbox including a worm wheel which is connected to the subsea valve for actuating the valve. The gearbox includes a seal which is disposed between the worm wheel and the housing for sealing the worm wheel relative to the housing so that lubricant disposed within the enclosure for lubricating the gearbox is sealed within the enclosure. A pressure compensator is disposed within the enclosure for maintaining pressure of the lubricant disposed within the enclosure at substantially the same pressure as the pressure of seawater outside the gearbox. The pressure compensator includes a cylindrical wall having a first and a second end, the wall defining a chamber.