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  2. Pilot-operated relief valve - Wikipedia

    en.wikipedia.org/wiki/Pilot-operated_relief_valve

    PORV are also called pilot-operated safety valve (POSV), pilot-operated pressure relief valve (POPRV), or pilot-operated safety relief valve (POSRV), depending on the manufacturer and the application. Technically POPRV is the most generic term, but PORV is often used generically (as in this article) even though it should refer to valves in ...

  3. Three Mile Island accident - Wikipedia

    en.wikipedia.org/wiki/Three_Mile_Island_accident

    In fact, the light when on only indicated that the PORV pilot valve's solenoid was powered, not the actual status of the PORV. [40] While the main relief valve was stuck open, the operators believed the unlighted lamp meant the valve was shut. As a result, they did not correctly diagnose the problem for several hours. [41]

  4. Surge control - Wikipedia

    en.wikipedia.org/wiki/Surge_control

    Pilot operated surge relief valves are typically used to protect pipelines that move low viscosity products like gasoline or diesel. This style of valve is installed downstream of the pump/valve that creates the surge. The valve is controlled by an external, normally closed pilot valve.

  5. Safety valve - Wikipedia

    en.wikipedia.org/wiki/Safety_valve

    An oxygen safety relief valve DN250-safety valves. A safety valve is a valve that acts as a fail-safe.An example of safety valve is a pressure relief valve (PRV), which automatically releases a substance from a boiler, pressure vessel, or other system, when the pressure or temperature exceeds preset limits.

  6. Pilot valve - Wikipedia

    en.wikipedia.org/wiki/Pilot_valve

    Pilot valves are useful because they allow a small and easily operated feed to control a much higher pressure or higher flow feed, which would otherwise require a much larger force to operate; indeed, this is even useful when a solenoid is used to operate the valve. Pilot valves are often used in critical applications (e.g., emergency and SIS ...

  7. Relief valve - Wikipedia

    en.wikipedia.org/wiki/Relief_valve

    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.

  8. Piping and instrumentation diagram - Wikipedia

    en.wikipedia.org/wiki/Piping_and_instrumentation...

    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) Miscellaneous - vents, drains, flanges, special fittings, sampling lines, reducers and swages; Interfaces for class changes; Computer control system

  9. Talk:Pilot-operated relief valve - Wikipedia

    en.wikipedia.org/wiki/Talk:Pilot-operated_relief...

    In the diagram 'Cutaway view of PORV' the pilot tube is labelled 'pitot tube', which is confusing and wrong. A pitot tube would be pointing directly into the direction of flow. I do not know how to edit the diagram: I leave that to those with more experience. 106.69.240.142 06:23, 2 March 2017 (UTC)Chris Carter . Just noticed the same thing.