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Cylinder, with slide valve removed to show ports A double-acting slide valve cylinder. Steam enters via the steam port SP, and is admitted by the slide valve SV through the upper passage S to push down the piston P. At the same time, exhaust steam from below the piston passes back up the lower passage S, via the valve cavity, to exhaust E. As ...
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.
Needle valve for accurate flow control; 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 ...
Process control instrumentation and designation (names, numbers, unique tag identifiers), including: Valves and their types and identifications (e.g. isolation, shutoff, relief and safety valves, valve interlocks) Control inputs and outputs (sensors and final elements, interlocks)
Control valves can also work with hydraulic actuators (also known as hydraulic pilots). These types of valves are also known as automatic control valves. The hydraulic actuators respond to changes of pressure or flow and will open/close the valve. Automatic control valves do not require an external power source, meaning that the fluid pressure ...
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.
All mass flow controllers have an inlet port, an outlet port, a mass flow sensor and a proportional control valve. The MFC is fitted with a closed loop control system which is given an input signal by the operator (or an external circuit/computer) that it compares to the value from the mass flow sensor and adjusts the proportional valve ...
Ordinary valves can have many ports and fluid paths. A 2-way valve, for example, has 2 ports; if the valve is open, then the two ports are connected and fluid may flow between the ports; if the valve is closed, then ports are isolated. If the valve is open when the solenoid is not energized, then the valve is termed normally open (N.O.).