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A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. [ 1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level. In automatic control terminology, a control valve is ...
A solenoid valve is an electromechanically operated valve . Solenoid valves differ in the characteristics of the electric current they use, the strength of the magnetic field they generate, the mechanism they use to regulate the fluid, and the type and characteristics of fluid they control. The mechanism varies from linear action, plunger-type ...
The most common final control element in the process control industries is the control valve. The control valve manipulates a flowing fluid, such as gas, steam, water, or chemical compounds, to compensate for the load disturbance and keep the regulated process variable as close as possible to the desired set point. [ 1]
Electrohydraulic servo valves may consist of one or more stages. A single-stage servo valve uses a torque motor to directly position a spool valve. Single-stage servo valves suffer from limitations in flow capability and stability due to torque motor power requirements.
These water valves are operated by rotary handles. A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category.
Flow coefficient. The flow coefficient of a device is a relative measure of its efficiency at allowing fluid flow. It describes the relationship between the pressure drop across an orifice valve or other assembly and the corresponding flow rate . Mathematically the flow coefficient Cv (or flow-capacity rating of valve) can be expressed as. where.
Valve actuator. Electric actuator (blue cylinder) on a valve in a power plant. A black handwheel is visible on the actuator, which allows manual positioning of the valve. The blue valve body is visible in-line with the pipe. The valve actuator opens or closes the butterfly disc of the valve based on electrical signals sent to the actuator.
Pinch valve, for slurry flow regulation and control. Piston valve, for regulating fluids that carry solids in suspension. Piston valve (steam engine) Plug valve, slim valve for on–off control but with some pressure drop. Solenoid valve, an electrically actuated valve for hydraulic or pneumatic fluid control.