Control valves are used to change process conditions such as flow, temperature, level, and pH. A complete control system would include: a sensor, controller, positioner or current to pressure transducer, and control valve. Globe valves, such as the Dwyer Series 2000VA/ 3000WA Hi-Flow™ Control Valve, are a very common type of control valve.
The Dwyer Hi-Flow™ Series control valves have pneumatic actuators that modulate the valve for flow control. The opening, closing and throttling of the valve plug is accomplished by varying the air pressure to the diaphragm in the actuator. Typically the control pressure signal is 3 to 15 psig. There are two types of actuators: Air-To-Lower and Air-To- Raise. Continue reading “Control Valve Actuator Sizing and Valve Action Selection”