| 摘要 |
A valve system and method is disclosed that includes, in one preferred embodiment, a compact valve system that may be configured in many different ways so as to be especially suitable for conforming to the dimensional requirements of many particular subsea installations such as lower riser packages. Thus, the height of the hydraulic actuator and/or manual override operators can be varied depending on the necessary configuration. However, operation of the manual override operators is the same as previously utilized subsea manual override operators. In one presently preferred embodiment, a hydraulic actuator which may be a fail-safe actuator, is connected to a gate valve utilizing an operating stem which extends through a first bonnet secured to one side of a gate valve body. A moveable gate is attached to the operating stem and is therefore operably connected for control by the hydraulic actuator. On an opposite side of the gate valve body, a second bonnet is secured. Attached to the second bonnet is a manual override operator having a rotary drive shaft and slave member. The slave member is attached to a balance stem which is secured to an opposite side of the gate with respect to the operating stem. The rotary drive shaft and slave member comprise reverse threads to thereby operate in the same manner as if the manual override operator were operably secured to the hydraulic actuator. The valve body is preferably symmetrical such that the position of the hydraulic actuator and manual override operator could be switched, if desired.
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