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Manual Linear Actuated Subsea Gate Valve

IP.com Disclosure Number: IPCOM000241658D
Publication Date: 2015-May-20
Document File: 2 page(s) / 17K

Publishing Venue

The IP.com Prior Art Database

Abstract

A manually operated actuator for a sliding gate valve designed for use in a subsea environment. The actuator would be similar in concept to that typically used on existing hydraulically actuated subsea gate valves that are fitted with a linear override mechanism, which use a power spring, to return the valve to the unactuated position. In this case, the tool used to move the valve between positions (i.e. open to closed or vice versa) would only need to be capable of pushing the valve stem in the direction required to compress the power spring. Alternatively, the actuator may not be fitted with a power spring, in which case the tool used to move the valve between positions would need to be able to both push and pull the valve stem, in order to move the valve between positions (i.e. open to closed or vice versa). A locking device would be required for either design, such that the valve would not unintentionally move from the open to closed position or vice versa.

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Manual Linear Actuated Subsea Gate Valve

Abstract                

A manually operated actuator for a sliding gate valve designed for use in a subsea environment.  The actuator would be similar in concept to that typically used on existing hydraulically actuated subsea gate valves that are fitted with a linear override mechanism, which use a power spring, to return the valve to the unactuated position.  In this case, the tool used to move the valve between positions (i.e. open to closed or vice versa) would only need to be capable of pushing the valve stem in the direction required to compress the power spring.  Alternatively, the actuator may not be fitted with a power spring, in which case the tool used to move the valve between positions would need to be able to both push and pull the valve stem, in order to move the valve between positions (i.e. open to closed or vice versa).  A locking device would be required for either design, such that the valve would not unintentionally move from the open to closed position or vice versa.

Main Body

Background of the invention

This invention relates generally to gate valve actuators, and more particularly to manually operated actuators for subsea gate valves as used on subsea trees, manifolds, pipeline end terminations, etc.

For some time the offshore oil and gas industry has required manual actuators for operating gate valves on subsea well Christmas trees, pipe manifolds and other underwater subsea production system apparatus, and such actuators of various designs are in widespread use for this purpose.  Existing valves of this kind use a threaded drive mechanism, however these are prone to failure due to galling of the threads on the interfacing components within the valve actuator.

Existing hydraulically actuated subsea gate valves are often fitted with a manual override mechanism such that the valve can be manually moved between positions (i.e. open to closed or vice versa) using a tool deployed by a diver or by a Remote Operated Vehicle (ROV).  Such manual override mechanisms involve either a rotary or a linear actuation override mechanism. 

Rotary override mechanisms involve the use of a rotary tool (deployed by diver or ROV) which locates in receptacle at the rear of the actuator (in order to provide a torque reaction point) combined with a threaded drive mechanism within the actuator, to move the valve between positions.  A rotary override mechanism has the advantage that the rotary tool can be removed at any time during the operation and the valve will remain in the position it was last in (i.e. open, closed, or partway in between), however such rotary override mechanisms are prone to failure due to galling of the threads on the interfacing components within the actuator. 

Linear override mechanisms involve the use a hydraulic cylinder (deployed by diver or ROV) which attaches to the rear of the actuator (in order to provide a push reaction point) and pushes the valve...