List of valves
Valves are quite diverse and may be classified into a number types.
Basic Types - by operating principle
Valves can be categorized into the following types, based on their operating mechanism.
- Ball valve, for on/off control without pressure drop. Ideal for quick shut-off, since a 90° turn completely shuts-off, compared to multiple 360° turns for other manual valves.
- Butterfly valve, for on/off flow control in large diameter pipes.
- Choke valve, raises or lowers a solid cylinder placed around or inside a second cylinder with holes or slots. Used for high pressure drops found in oil and gas wellheads, not to be confused with engine choke valve.
- Diaphragm or Membrane valve, controls flow by movement of a diaphragm. Used in pharmaceutical applications.
- Gate valve, mainly for on/off control, with low pressure drop.
- Globe valve, good for regulating flow. Uses a cylinder movement over a seat.
- Knife valve, similar to a gate valve, but usually more compact. Often used for slurries or powders on/off control.
- Needle valve for accurate flow control.
- Pinch valve, for slurry flow regulation and control.
- Piston valve, for regulating fluids that carry solids in suspension.
- Plug valve, slim valve for on/off control but with some pressure drop.
- Solenoid valve, an electrically actuated valve for hydraulic or pneumatic fluid control
- Spool Valve, for hydraulic control, similar to the choke valve
Basic Types - by function
Valves can be categorized also based on their function
- Check valve or non-return valve, allows the fluid to pass in one direction only.
- Flow control valve, to maintain and control a variable flow rate through the valve
- Poppet valve, commonly used in piston engines to regulate the fuel mixture intake and exhaust
- Pressure Reducing Valve, to regulate the pressure of the fluid.
- Thermal expansion valve, used in refrigeration and air conditioning systems.
- Safety valve or relief valve: operates automatically at a set pressure to correct a potentially dangerous situation, typically over-pressure
- Sampling valve
These are more specific types of valves, used only in particular fields or applications. Often they are subcategories of the classification by operating principle and by function.
- Aspin valve: a cone-shaped metal part fitted to the cylinder head of an engine
- Ball cock: often used as a water level controller (cistern)
- Bibcock: provides a connection to a flexible hosepipe
- Blast valve: prevents rapid overpressuring in a fallout shelter or a bunker
- Boston valve: three-part two-port check valve used on inflatable boats, air mattresses, airbeds etc.; available in two sizes, normal and small
- Cock: colloquial term for a small valve or a stopcock
- Ceramic Disc valve, used mainly in high duty cycle applications or on abrasive fluids. Ceramic disc can also provide Class IV seat leakage
- Choke valve, Butterfly valve used to limit air intake in internal combustion engine. Not to be confused with choke valves used in industrial flow control.
- Clapper valve: a type of check valve used in the Siamese fire appliance to allow only 1 hose to be connected instead of two (the clapper valve blocks the other side from leaking out).
- Demand valve: on a diving regulator
- Double beat valve
- Double check valve
- Duckbill valve
- Flapper valve
- Heimlich valve: a specific one-way valve used on the end of chest drain tubes to treat a pneumothorax
- Foot valve: a check valve on the foot of a suction line to prevent backflow
- Four-way valve: was used to control the flow of steam to the cylinder of early double-acting steam engines
- Freeze seal/Freeze plug: in which freezing and melting the fluid creates and removes a plug of frozen material acting as the valve
- Gas pressure regulator regulates the flow and pressure of a gas
- Heart valve: regulates blood flow through the heart in many organisms
- Hydrodynamic vortex valve: a passive flow control valve that uses hydrodynamic forces to regulate flow
- Larner–Johnson Valve: needle control valve often in large sizes used in water supply systems
- Leaf valve: one-way valve consisting of a diagonal obstruction with an opening covered by a hinged flap
- Pilot valve: regulates flow or pressure to other valves
- Pinch valve, "beach ball valve": simple, single-part two-port check valve made from soft plastic and molded on to inflatable units such as beach balls, air mattresses, water wings; can be inflated by pump or by mouth.
- Plunger valve: To regulate flow while lowering the pressure
- Poppet valve and sleeve valve: commonly used in piston engines to regulate the fuel mixture intake and exhaust
- Pressure regulator or pressure reducing valve (PRV): reduces pressure to a preset level downstream of the valve
- Pressure sustaining valve, or back-pressure regulator: maintains pressure at a preset level upstream of the valve
- Presta, Schrader or Dunlop valves are used to hold the air in bicycle tires
- 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
- Regulator: used in SCUBA diving equipment and in gas cooking equipment to reduce the high pressure gas supply to a lower working pressure
- Rocker valve
- Rotolock valve
- Rotary valves and piston valves: parts of brass instruments used to change their pitch
- Rupture disc: a one time use replaceable valve for rapid pressure relief, used to protect piping systems from excessive pressure or vacuum; more reliable than a safety valve
- Saddle valve: where allowed, is used to tap a pipe for a low-flow need
- Schrader valve: used to hold the air inside automobile tires
- Slide valve: used in early steam engines to control admission and emission of steam from the piston.
- Stopcock: restricts or isolates flow through a pipe
- Swirl valve: A specially designed Joule-Thompson pressure reduction/expansion valve imparting a centrifugal force upon the discharge stream for improving gas–liquid phase separation
- Tap (British English), faucet (American English): the common name for a valve used in homes to regulate water flow
- Tesla valve: A form of check valve with no moving parts, invented by Nikola Tesla for use with fluids.
- Thermostatic mixing valve
- Thermostatic radiator valve
- Trap primer: sometimes include other types of valves, or are valves themselves
- Vacuum breaker valve: prevents the back-siphonage of contaminated water into pressurized drinkable water supplies