1. Field of the Disclosure
The present disclosure relates in general to valves associated with hydrocarbon recovery wells, and in particular to actuators to actuate valves. Yet more particularly, the present disclosure relates to an adapter for coupling together actuators of varying designs to valve stems.
2. Description of Related Art
Valves typically have a valve member attached to a linearly translating member, such as a stem, for moving the valve member between the open and closed positions. Some valves, such as gate valves, have an aperture that aligns with the bore to allow flow through the valve. The valve can be normally open, and thus the valve is closed when it is moved linearly to push the aperture out of alignment with the bore. Alternatively, a valve can be normally closed, and thus the valve is opened when it is moved linearly to position the aperture into alignment with the bore. Regardless of whether the valve is normally open or normally closed, the valve can be actuated, or moved between the open and closed position by a valve actuator.
Certain valve actuators have threaded downstops for connecting to the valve stem. If the valve stem is a nub stem instead of a threaded stem, an actuator with a threaded downstop would not be able to connect to the valve stem. Often valve actuators that have downstops with profiles, instead of threads, for mating with nub stems have to be assembled in a shop in order to compress the biasing member and insert a snap ring, to maintain the biasing member in a compressed position and trap the biasing member within the valve body. Having to use a press in a shop to disassemble or reassemble an actuator assembly requires moving the actuator assembly from the valve assembly location to a shop. Therefore certain operations, such as replacing parts, performing maintenance operations, or retrofitting a new actuator onto an existing valve cannot be undertaken in the field. Performing such operations in a shop with a press can be costly and time consuming and can lead to excess downtime of the systems to which the valve assembly is attached.