Valve
A valve is a mechanical device that regulates the flow of fluids (either gases and liquids) by opening, closing, or partially obstructing various passageways.
There are a number of names for particular types of valve:
- Ball cock, often used as a water level controller (cistern)
- Ball valve
- Bibcock
- Butterfly valve
- Cock, colloquial term for a small valve
- Gate valve
- Globe valve
- Hydraulic valve (diaphragm valve)
- Non-return valve or check valve, allows the fluid to pass in one direction only
- Pilot valves regulate flow or pressure to other valves.
- Solenoid valve, an electrically controlled hydraulic valve
- Tap (British english), Faucet (US english)
- A flow control valve maintains a constant flowrate through the valve
- A safety valve operates automatically to correct a potentially dangerous situation.
- 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.
- The poppet valve is commonly used in piston engines to regulate the fuel mixture intake and exhaust. The sleeve valve is another valve type used for this purpose.
- Heart valves regulate blood flow through the heart in many organisms.
- Thermionic valves, also known as vacuum tubes, are used in valve amplifiers to amplify sound signals.
- Three way valves route fluid from one direction to another.