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Partial stroke testing (or PST) is a technique used in a control system to allow the user to test a percentage of the possible failure modes of a shut down valve without the need to physically close the 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.
Double pipe heat exchanger Fixed straight tubes heat exchanger: U-shaped tubes heat exchanger Spiral heat exchanger Covered gas vent Curved gas vent Air filter: Funnel or tundish: Steam trap: Viewing glass Pressure reducing valve: Valve: Gate valve: Control valve: Manual valve Check valve: Needle valve: Butterfly valve: Diaphragm valve: Ball ...
A Larner–Johnson valve is a mechanism used in dams and water pumping to control the flow of water through large pipes. The valve is suited to handling high velocity flow with minimal turbulence, even when partially open, and the actuating force can be provided by the water flow it is controlling.
To keep water hammer low, pipe-sizing charts for some applications recommend flow velocity at or below 1.5 m/s (4.9 ft/s). Fit slowly closing valves. Toilet fill valves are available in a quiet fill type that closes quietly. Non-slam check valves do not rely on fluid flow to close and will do so before the water flow reaches significant velocity.
A relief valve DN25 on cooling water pipe from heat exchanger Schematic diagram of a conventional spring-loaded pressure relief valve. A relief valve or pressure relief valve (PRV) is a type of safety valve used to control or limit the pressure in a system; excessive pressure might otherwise build up and create a process upset, instrument or equipment failure, explosion, or fire.
This means that they are installed as a component of the completion string and run in during completion. Retrieving the valve, should it malfunction, requires a workover. The full name for this most common type of downhole safety valve is a Tubing Retrievable Surface Controlled Sub-Surface Valve, shortened in completion diagrams to TRSCSSV.
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. Another valve actuator is visible in the background, with windows to indicate the valve position. A valve actuator is the mechanism for opening and closing a valve. Manually ...