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A shutdown valve (also referred to as SDV or emergency shutdown valve, ESV, ESD, or ESDV; or safety shutoff valve) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.
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Isolation valves must effectively stop the passage of fluids. [4] Gate valves, ball valves and plug valves are generally considered to provide tight and effective shut-off. Globe valves and Butterfly valves may not be tight shut-off due to wear on the plug or the seat, or due to their design, and may not be appropriate to provide effective ...
A DIN standard for gas cylinder valves for test pressures up to 300 bar (4,400 psi). EN 15202 [9] A European standard for LPG equipment and accessories, specifying LPG cylinder valve connections. [10] EN 417: European norm specification concerning non-refillable metallic cartridges for liquefied petroleum gases.
Its function is distinct from that of pressure relief valves, which are passive devices opening if pressure reaches a value above the process safety trip, but still below the design pressure of the equipment. Relief valves complement the PSD. A process plant is typically divided into isolatable sections by emergency shutdown valves (ESDVs).
Valves can be categorized into the following types, based on their operating mechanism: Ball valve, for on–off control without pressure drop. Ideal for quick shut-off, since a 90° turn completely shuts off, compared to multiple 360° turns for other manual valves; Butterfly valve, for on–off flow control in large diameter pipes
Plug valves are valves with cylindrical or conically tapered "plugs" which can be rotated inside the valve body to control flow through the valve. The plugs in plug valves have one or more hollow passageways going sideways through the plug, so that fluid can flow through the plug when the valve is open. Plug valves are simple and often economical.
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.