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 contol
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

Specific types

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 and Schrader 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