Ball valve, for on/off control without pressure drop. Butterfly valve, for flow regulation in large pipe diameters.Choke valve, a valve that lifts up and down a solid cylinder which is placed around or inside another cylinder which has holes or slots. Used for high pressure drops found in oil and gas wellheads. Check valve or non-return valve, allows the fluid to pass in one direction only.Diaphragm valve, some are sanitary predominantly used in the pharmaceutical and foodstuff industry.Expansion valve, used pressure reduction of fluid in general. Type of restrictor valve to reduce refrigerant pressure and temperature in short period of time in adiabatic expansion.Gate valve, mainly for on/off control, with low pressure drop.Globe valve, good for regulating flow.Knife valve, for slurries or powders on/off control.Needle valve for accurate flow control. Piston valve, for regulating fluids that carry solids in suspension. Pinch valve, for slurry flow regulation. Plug valve, slim valve for on/off control but with some pressure drop. 4-stroke cycle engine valves: an application of piston valve spin 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 overpressures in a fallout shelter or a bunker Cock: colloquial term for a small valve or a stopcock Demand valve: on a diving regulator Double beat valve Double check valve Duckbill valve Flipper valve Flow control valve: an application which maintains a constant flow rate through the 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 Freeze valve: 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 Leaf valve: one-way valve consisting of a diagonal obstruction with an opening covered by a hinged flap Pilot valve: regulate flow or pressure to other valves Poppet valve and sleeve valve: commonly used in piston engines to regulate the fuel mixture intake and exhaust Pressure reducing valve (PRV), or pressure regulator: 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 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 Safety valve or relief valve: operates automatically at a set differential pressure to correct a potentially dangerous situation, typically over-pressure