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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 ...
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]
Control Valve Handbook – Fisher Controls International (4th Edition) – a complete 297-page online book. Process Instrumentation (Lecture 8): Control valves Archived 2015-05-29 at the Wayback Machine – an article from a University of South Australia website.
Pilot-operated relief valve. Cutaway view of PORV. Like other pressure relief valves (PRV), pilot-operated relief valves ( PORV) are used for emergency relief during overpressure events (e.g., a tank gets too hot and the expanding fluid increases the pressure to dangerous levels). PORV are also called pilot-operated safety valve ( POSV ), pilot ...
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.
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 ...
The hot water supply hose of the umbilical is connected to a supply manifold at the right hip of the suit, which has a set of valves to allow the diver to control flow to the front and back of the torso and the arms and legs, and to dump the supply to the environment if the water is too hot or too cold.
In mathematical statistics, the Fisher information (sometimes simply called information[ 1]) is a way of measuring the amount of information that an observable random variable X carries about an unknown parameter θ of a distribution that models X. Formally, it is the variance of the score, or the expected value of the observed information .