| 摘要 |
A hydraulically operated actuator for a sliding gate valve designed for use in a subsea environment. The actuator includes a manual override system that functions independently of the actuator's hydraulic piston and return spring, an externally accessible valve gate drift adjustment, an externally adjustable upstop for the actuator stem, a stem thread assembly that can be manufactured from a material different from the actuator stem to prevent or reduce the possibility of thread galling, a hydraulic control pressure porting system integral with the hydraulic cylinder to minimize space requirements, and a facility for accommodating an optional external electrical stem position indicator package.
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