Valve
For other uses, see Valve (disambiguation).A
valve is a device that regulates the flow of
fluids (either
gases, fluidised solids, slurries or
liquids) 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 engines 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.
*
Demand valve on a
diving regulator.
*
Double check valve.
* A
flow control valve maintains a constant flow rate through the valve.
*
Freeze valve, in which freezing and melting the fluid creates and removes a plug of frozen material acting as the valve.
*
Gate valve, mainly for on/off control.
*
Choke valve, Is a heavy duty valve which controls flow to a certain Flow Coefficient (
CV) determined by how far the valve is opened, regularly used in the
Oil industry.
*
Globe valve, which is good for regulating flow.
* A
heart valve regulates blood flow through the heart in many organisms.
*
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.
*
Needle valve for gently releasing high pressures.
*
Pilot valves regulate flow or pressure to other valves.
*
Piston valves
*
Plug valve, for on/off control.
* A
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.
* 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.
*
Presta and
Schrader valves are used to hold the air in
bicycle tires.
* A
Reed valve consists of two or more flexible materials pressed together along much of their length, but with the influx area open to allow one-way flow, much like a heart 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
*
Rotary valves and
piston valves are parts of brass instruments used to change their pitch.
* A
safety valve or
relief valve operates automatically at a set differential pressure to correct a potentially dangerous situation, typically over-pressure.
*
Schrader valves are used to hold the air inside
automobile tires.
*
Solenoid valve, an electrically controlled hydraulic or pneumatic valve.
*
Stopcocks 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.
* A
three-way valve routes fluid from one direction to another.
*
Vacuum breaker valves prevent the back-
siphonage of contaminated water into pressurized drinkable water supplies.
]Image:Valve2.jpg|Ball valveImage:Globevalve.jpg|Globe valve*
Backwater valves
*
Plumbing*
Variable Valve Timing *
Zone valve*
wog (
aka WOG)
*
Valve Sizing and Selection*
Flow in known Design Types of Shut-off Valves
