- Every valve needs a means by which it can be operated. There are a variety of options to achieve this by means of hand wheels, levers, wrench, gears, and actuators. Actuators are a means by which a valve can be automated so that no human interaction with the valve put together is necessary to cycle the valve.
- Actuators can be remotely operated and can act as shutdown mechanisms in case of an emergency situation, wherein human interaction can be dangerous. At a basic level, an actuator is a control mechanism that is operated by an energy source. This energy can be hydraulic pressure, pneumatic pressure, or electric current which moves the internal mechanical parts of the actuator.
- They can be designed to fail-open (in the case of actuator failure, the valve will stay open) or fail-close (in the case of actuator failure, the valve will stay closed). They also are distinguished by whether they are for quarter-turn (ball valves, plug valves, butterfly valves etc..) Or linear (gate valves, globe valves etc..) Valve operation."
- Flowchem make pneumatic actuators utilize compressed air to generate the operating energy. These actuators are quick to respond, but are not ideal for environments under high pressures, as gas is compressible. Pneumatic actuators can be either spring return or double acting.
- Flowchem actuators in a spring return configuration have air or liquid supplied to only one side of the piston, and the energy to move the mechanisms comes from a spring on the opposite side. This arrangement uses the air or liquid as energy to open or close the valve, while the spring acts to affect the opposite motion