1. Valve A valve is a device that regulates the flow of fluids (either gases, fluidized solids, slurries, or liquids) by opening, closing, or partially obstructing various passageways. fluidsgasesliquidsfluidsgasesliquids Valves are used in a variety of applications including industrial, military, commercial, residential, transportation. industrial militarycommercial transportationindustrial militarycommercial transportation

2. Valve 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, like in Otto cycle engines driven by a camshaft, where they play a major role in engine cycle control. Steam engines appliancesOtto cycle enginescamshaftSteam engines appliancesOtto cycle enginescamshaft

3. Application A large variety of valves are available and have many applications with sizes ranging from tiny to huge. The cost of valves ranges from very cheap simple disposable valves in some items to very expensive valves for specialized applications. Often not realized by some, small valves are even inside some common household items including liquid or gel mini-pump dispenser spigots, spray devices, some rubber bulbs for pumping air, etc., manual air pumps and some other pumps, and laundry washers.

4. Application Valves are almost as ubiquitous as electrical switches. Often a valve is part of some object, the valve body and the object made in one piece; for example, a separatory funnel. Faucets, taps, and spigots are all variations of valves. Many fluid systems such as water and natural gas lines in houses and other buildings have valves. Fluid systems in chemical and power plants and other facilities have numerous valves to control fluid flow. separatory funnelFaucetstapsnatural gaschemicalpower plants separatory funnelFaucetstapsnatural gaschemicalpower plants

5. Valve parts BodyPorts Connections to ports Discs and rotors SeatStemBonnet

6. Valve operating positions 2-way valves 3-way valves

7. Types of valves 4-stroke cycle engine valves4-stroke cycle engine valves, 4-stroke cycle engine valves Ball cockBall cock, often used as a water level controller (cistern). Ball cock Ball valveBall valve, which is good for on/off control. Ball valve BibcockBibcock, provides a connection to a flexible hosepipe hosepipe Bibcock hosepipe Blast valveBlast valve, used to prevent rapid overpressures in a fallout shelter or a bunker. fallout shelterbunker Blast valvefallout shelterbunker Butterfly valveButterfly valve, particularly in large pipes. Butterfly valve Check valveCheck valve or Non-return valve, allows the fluid to pass in one direction only. Check valve CockCock, colloquial term for a small valve or a stopcock. stopcock Cock stopcock

8. Types of valves Demand valveDemand valve on a diving regulator. diving regulator Demand valvediving regulator Diaphragm valveDiaphragm valve, a sanitary valve predominantly used in the pharmaceutical industry Diaphragm valve Double check valveDouble check valve. Double check valve A flow control valve maintains a constant flow rate through the valve. flow control valveflow control valve Freeze valveFreeze valve, in which freezing and melting the fluid creates and removes a plug of frozen material acting as the valve. Freeze valve Gate valveGate valve, mainly for on/off control. Gate valve Choke valveChoke 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. CVOil industry Choke valveCVOil industry Globe valveGlobe valve, which is good for regulating flow. Globe valve A heart valve regulates blood flow through the heart in many organisms. heart valveheart valve HydraulicHydraulic valve (diaphragm valve). Hydraulic

9. Types of valves A leaf valve is a one-way valve consisting of a diagonal obstruction with an opening covered by a hinged flap. leaf valveleaf valve Needle valveNeedle valve for gently releasing high pressures. Needle valve Pilot valvesPilot valves regulate flow or pressure to other valves. Pilot valves Piston valves Piston valves Plug valvePlug valve, for on/off control. Plug valve 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. poppet valvepiston enginesexhaustsleeve valvepoppet valvepiston enginesexhaustsleeve valve A pressure reducing valve, also called pressure regulator, reduces pressure to a preset level downstream of the valve. pressure reducing valvepressure reducing valve A pressure sustaining valve, also called back-pressure regulator, maintains pressure at a preset level upstream of the valve. pressure sustaining valvepressure sustaining valve PrestaPresta and Schrader valves are used to hold the air in bicycle tires. Schrader valvesbicycle tires PrestaSchrader valvesbicycle 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 Reed valveReed valve

10. Types of valves 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 SCUBA diving equipmentSCUBA diving equipment Rotary valvesRotary valves and piston valves are parts of brass instruments used to change their pitch. piston valves Rotary valvespiston valves A safety valve or relief valve operates automatically at a set differential pressure to correct a potentially dangerous situation, typically over-pressure. safety valverelief valvesafety valverelief valve Schrader valvesSchrader valves are used to hold the air inside automobile tires. automobiletires Schrader valvesautomobiletires Solenoid valveSolenoid valve, an electrically controlled hydraulic or pneumatic valve. Solenoid valve StopcocksStopcocks restrict or isolate the flow through a pipe of a liquid or gas. Stopcocks TapTap (British English), faucet (American English) is the common name for a valve used in homes to regulate water flow. Tap 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. siphonage