When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Piping and plumbing fitting - Wikipedia

    en.wikipedia.org/wiki/Piping_and_plumbing_fitting

    Valves stop (or regulate) the flow of liquids or gases. They are categorized by application, such as isolation, throttling, and non-return. Isolation valves temporarily disconnect part of a piping system to allow maintenance or repair, for example. Isolation valves are typically left in either a fully open or closed position.

  3. Shutdown valve - Wikipedia

    en.wikipedia.org/wiki/Shutdown_valve

    A blowdown valve (BDV) is a type of shutdown valve designed to depressurize a pressure vessel by directing vapour to a flare, vent or blowdown stack in an emergency. BDVs fail-safe to the open position upon failure of the control system. [1] The type of valve, type of actuation and performance measurement are similar to an ESD valve.

  4. Valve actuator - Wikipedia

    en.wikipedia.org/wiki/Valve_actuator

    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 ...

  5. Piping and instrumentation diagram - Wikipedia

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

    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 ...

  6. Butterfly valve - Wikipedia

    en.wikipedia.org/wiki/Butterfly_valve

    Unlike a ball valve, the disc is always present within the flow, so it induces a pressure drop, even when open. A butterfly valve is from a family of valves called quarter-turn valves. In operation, the valve is fully open or closed when the disc is rotated a quarter turn. The "butterfly" is a metal disc mounted on a rod. When the valve is ...

  7. Gate valve - Wikipedia

    en.wikipedia.org/wiki/Gate_valve

    Gate valves are used to shut off the flow of liquids rather than for flow regulation, which is frequently done with a globe valve. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low flow resistance. [1] The size of the open flow path generally varies in a nonlinear manner as the gate is moved.

  8. Christmas tree (oil well) - Wikipedia

    en.wikipedia.org/wiki/Christmas_tree_(oil_well)

    The two lower valves are called the master valves (upper and lower respectively). Master valves are normally in the fully open position and are never opened or closed when the well is flowing (except in an emergency) to prevent erosion of the valve sealing surfaces. The lower master valve will normally be manually operated, while the upper ...

  9. List of valves - Wikipedia

    en.wikipedia.org/wiki/List_of_valves

    Saddle valve: where allowed, is used to tap a pipe for a low-flow need; Schrader valve: holds the air inside automobile tires; Security valve, a type of automatic shut-off valve (ASV): used to stop the flow of natural gas upon sudden pressure changes. Increased pressure or decreased pressure closes the valve (without using any external power ...