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Globe valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle. This has an opening that forms a seat onto which a movable plug[ 2] can be screwed in to close (or shut) the valve. The plug is also called a disc. [ 3]
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]
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. In an open valve, fluid flows in a direction from ...
Control valve. 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 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.
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.
The ASME B16 Standardization of Valves Flanges, Fittings and Gaskets Committee, which operates under ASME ’s Board on Pressure Technology Codes and Standards is responsible for standards covering valves, flanges, pipe fittings, gaskets and valve actuators for use in pressure services. The B16 Standards Committee currently meets once a year in ...