A is a device that regulates the flow of Fluid s (either Gas es, fluidised solids, slurries or Liquid s) by opening, closing, or partially obstructing various passageways.
Valves are used in a variety of industrial, military, commercial, and residential applications.
Some valves are driven by pressure only, they are mainly used for safety purposes in Steam Engine s and domestic heating or cooking appliances. Others are used in a controlled way in Otto Cycle Engines driven by a camshaft, and they have a major part in engine cycle control.
- 4-stroke Cycle Engine Valves ,
- Ball Cock , often used as a water level controller (cistern);
- Ball Valve , which is good for on/off control;
- Bibcock , provides a connection to a flexible Hosepipe
- Blast Valve , used to prevent rapid overpressures in a Fallout Shelter or a Bunker ;
- Butterfly Valve , particularly in large pipes;
- Check Valve or Non-return valve, allows the fluid to pass in one direction only;
- Cock , colloquial term for a small valve or a Stopcock ;
- Double Check Valve ;
- Freeze Valve , in which freezing and melting the fluid creates and removes a plug of material acting as the valve;
- Gate Valve , mainly for on/off control;
- Globe Valve , which is good for regulating flow;
- Hydraulic Valve (diaphragm valve);
- A Leaf Valve is a one-way valve consisting of a diagonal obstruction with an opening covered by a hinged flap.
- Pilot Valve s regulate flow or pressure to other valves;
- Plug Valve , for on/off control;
- Presta and Schrader Valve s are used to hold the air in Bicycle Tyre s.
- Rotary Valve s and Piston Valve s are parts of brass instruments used to change their pitch.
- Schrader Valve s are used to hold the air inside Automobile Tyre s.
- Solenoid Valve , an electrically controlled hydraulic or pneumatic valve;
- Stopcock s restrict or isolate the flow through a pipe of a liquid or gas.
- Tap (British English), faucet (American English) is the common name for a valve used in homes to regulate water flow;
Different valves may be used for a variety of purposes:
- A Flow Control Valve maintains a constant flow rate through the valve.
- A Heart Valve regulates blood flow through the heart in many organisms.
- A Poppet Valve is commonly used in Piston Engine s to regulate the fuel mixture intake and exhaust. The Sleeve Valve is another valve type used for this purpose.
- A Pressure Reducing Valve reduces pressure to a preset level downstream of the valve.
- A Pressure Sustaining Valve maintains pressure at a preset level upstream of the valve.
- A regulator is used in SCUBA Diving Equipment and in gas cooking equipment to reduce the high pressure gas supply to a lower working pressure
- A Safety Valve or Relief Valve operates automatically at a set differential pressure to correct a potentially dangerous situation, typically over-pressure.
- A three-way valve routes fluid from one direction to another.
- Vacuum breaker valves prevent the back-siphonage of contaminated water into pressurized, potable water supplies.
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