Steam injection valve actuator, system, and method

A valve actuator system comprising:

• a valve actuator assembly having a body defining an exterior that is sealed and an interior cavity, and a piston coupled to a piston rod and movable within a piston cylinder provided within the interior cavity, the piston cylinder having a first chamber on a first side of the piston and a second chamber on a second rod side of the piston;
• one or more electronic components, including at least one processor, within the interior cavity, the one or more electronic components configured to send a signal to a valve of one or more manifolds to move the piston via controlled air pressure and to continuously monitor and/or determine a position of the piston rod relative to the piston cylinder;
• a fail-safe reservoir coupled to a source of air, the fail-safe reservoir connected to both the first chamber and the second chamber to provide operating air thereto;
• and
• a controller configured to communicate with the processor of the one or more electronic components remote from the body and to selectively monitor and control functions of the valve actuator system,
• wherein the first chamber is maintained at a constant pressure within the constraints of the system, and wherein the second chamber is varied in pressure to move and/or to hold the position of the piston to place the piston rod at a desired position relative to the piston cylinder,
• wherein a portion of the interior cavity is maintained at a positive pressure, such that the portion of the interior cavity is maintained at a pressure above a pressure adjacent the exterior of the body, and
• wherein the positive pressure of the portion of the interior cavity resists environmental conditions or contaminants from entering the interior cavity of the body.

A method of controlling a steam control valve of an industrial process, the industrial process including a valve actuator assembly having a body defining an exterior that is sealed and an interior cavity and a piston coupled to a piston rod and movable within a piston cylinder provided within the interior cavity, the piston cylinder having a first chamber on a first side of the piston and a second chamber on a second rod side of the piston, and the piston rod coupled to an actuator of the steam control valve, the method comprising:

• moving the piston, via one or more electronic components within the interior cavity, through controlled air pressure, the one or more electronic components including at least one processor configured to control the air pressure;
• continuously monitoring and/or determining, via the one or more electronic components, a position of the piston rod relative to the piston cylinder to control operation of the steam control valve;
• selectively monitoring and/or controlling, via a controller disposed remote from the valve actuator assembly and configured to communicate with the processor of the one or more electronic components, functions of the valve actuator system;
• and
• providing operating air from an external source of air to both the first chamber and the second chamber via a fail-safe reservoir disposed within the interior cavity of the body,
• wherein a portion of the interior cavity is maintained at a positive pressure, such that the portion of the interior cavity is maintained at a pressure above a pressure adjacent the exterior of the body, and
• wherein the positive pressure of the portion of the interior cavity resists environmental conditions or contaminants from entering the interior cavity of the body.