According to JIS, the definition of a valve is as follows:
A generic name for a device with a moveable feature that allows it to open and close a passageway in order to allow, prevent or control the flow of fluids.There are many different types of valves in the world, but the among the most typical manual valves used on steam systems are globe valves, ball valves, gate valves, and butterfly valves.
Valves may also be classified by how they are actuated:
Hydraulic: Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Hydraulic valve
is worked by the use of pressurized liquids.
Pneumatics: Pneumatics valve is worked by the use of pressurized gas to affect mechanical motion.
Manual: which is controlled by the human.
Solenoid: A solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid coil. Solenoid valves may have two or more ports: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports. Multiple solenoid valves can be placed together on a manifold.
Motor: Motor valve is refers to a valve that creates motion by a motor.
Basic types
Ball valve
A ball valve is a valve that opens by turning a handle, gearbox or other actuation methods attached to a ball inside the valve. The ball has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. The handle or lever will be inline with the port position letting you "see" the valve's position, position indicators will be applied to gearbox or actuators when required. Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore an excellent choice for shutoff applications. There are two type of ball valve based on the ball type, floating ball valve and trunnion mounted ball valve. Depends on the bore size, ball valve is separated into full port ball valve and reduced port ball valve. There are three type of body styles of ball valve: one-piece, two piece split, three piece split, top entry and welded, FBV ball valves are available in two piece split, three piece split and welded.
Butterfly valve
A butterfly valve is from a family of valves called quarter turn valves. The "butterfly" is a metal disc mounted on a rod. When the valve is closed, the disc is turned so that it completely blocks off the passageway. When the valve is open, the disc is rotated a quarter turn so that it allows unrestricted passage. The position of the disc is effected from outside the valve.
Choke valve
For the control of high pressure drop and contaminated fluids in gas/oil production, gas lift, water injection, depressurisation flow lines, glycol units, etc.
Check valve
Check valves are generally used in drip irrigation emitters and irrigation sprinklers. Composition disc valves are ideal for applications involving gritty liquids. A clapper valve is a type of check valve which is used in fire fighting. Poppet check valves find use in "macro" flow applications. Arterial check valves are used in applications requiring centrifugal pumps to prevent retrograde flow along the arterial line. Check valves are mechanical valves that permit gases and liquids to flow in only one direction, preventing process flow from reversing. They are classified as one-way directional valves. Fluid flow in the desired direction opens the valve, while backflow forces the valve closed. The mechanics of check valve operation are not complicated. Most check valves contain a ball that sits freely above the seat, which has only one through hole. The ball has a slightly larger diameter than that of the through hole. When the pressure behind the seat exceeds that above the ball, liquid is allowed to flow through the valve. But once the pressure above the ball exceeds the pressure below the seat, the ball returns to rest in the seat, forming a seal that prevents backflow.
Ceramic Disc valve
used mainly in high duty cycle applications or on abrasive fluids. Ceramic disc can also provide Class IV seat leakage
Diaphragm valve
Diaphragm valves are related to pinch valves. But use an elastomeric diaphragm, instead of an elastomeric liner in the valve body, to separate the flow stream from the closure element. Instead of pinching the liner closed to provide shut-off, the diaphragm is pushed into contact with the bottom of the valve body to provide shut-off. Diaphragm valves are excellent for controlling the flow of fluids containing suspended solids and offer the flexibility of being installed in any position. These types of valves have found widespread use in the pharmaceutical, food processing, and water treatment industries.
Gate valve
A gate valve, also known as a sluice valve, is a valve that opens by lifting a round or rectangular gate/wedge out of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces between the gate and seats are planar. The gate faces can form a wedge shape or they can be parallel. Typical gate valves should never be used for regulating flow, unless they are specifically designed for that purpose. On opening the gate valve, the flow path is enlarged in a highly nonlinear manner with respect to percent of opening. This means that flow rate does not change evenly with stem travel. Also, a partially open gate disk tends to vibrate from the fluid flow. Most of the flow change occurs near shutoff with a relatively high fluid velocity causing disk and seat wear and eventual leakage if used to regulate flow. Typical gate valves are designed to be fully opened or closed. When fully open, the typical gate valve has no obstruction in the flow path, resulting in very low friction loss.
Globe valve
Globe valve is a type which disc along the valve seat centerline movement. It??s very suitable for control the medium, because of this type of valve??s stem opening or closing at a short trip, and it has very reliable breaker function. Therefore, this type of valve is suitable for cutting, adjusting and throttling the medium.
Knife valve
Knife-type valve Knife gate valve - also known as knife type gate valve, knife-type slurry valve, has a simple structure and compact, well designed, light materials, sealing reliable, flexible and lightweight, small size, channel flow, flow resistance in small, light weight, easy to install and easy to demolition, etc., can be pressure 1.0MPa-2.5MPa, temperature -29-650 C degree, normal working circumstances. knife gate valve with its shearing function, may seal the surface of the adhesive curettage material, automatic removal of debris, stainless steel gate sealed to prevent leaks caused by corrosion.
Needle valve
Needle valves are similar in design and operation to the globe valve. Instead of a disk, a needle valve has a long tapered point at the end of the valve stem. The long taper of the valve element permits a much smaller seating surface area than that of the globe valve; therefore, the needle valve is more suitable as a throttle valve. Needle valves are used to control flow into delicate gauges, which might be damaged by sudden surges of fluid under pressure. Needle valves are also used to control the end of a work cycle, where it is desirable for motion to be brought slowly to a halt, and at other points where precise adjustments of flow are necessary and where a small rate of flow is desired.
Piston valve
A piston check valve, is essentially a lift check valve. It has a dashpot consisting of a piston and cylinder that provides a cushioning effect during operation. Because of the similarity in design to lift check valves, the flow characteristics through a piston check valve are essentially the same as through a lift check valve.
Pinch valve
The pinch control valve consists of a sleeve molded of rubber or other synthetic material and a pinching mechanism. All of the operating portions are completely external to the valve. The molded sleeve is referred to as the valve body.
Plug valve
Plug valves are valves with cylindrical or conically-tapered "plugs" which can be rotated inside the valve body to control flow through the valve. It have some other name,such as:plug valves,car plug valve,lubricated plug valve.The plugs in plug valves have one or more hollow passageways going sideways through the plug, so that fluid can flow through the plug when the valve is open. Plug valves are simple and often economical.
Spool valve
Iclued Rotary Spool Valve and Sliding Spool Valve.
The sliding spool four-way directional control valve is simila in operation to the two-way valve previously described in this chapter. It is simple in its principle of operation and is the most durable and trouble-free of all four-way directional control valves. The valve described in the following para- graphs is a manually operated type. The same principle is used in many remotely controlled directional control valves.
The thermal expansion
The thermal expansion valve is an automatic device which controls the flow of liquid refrigerant to theevaporator according to changes in superheat of the refrigerant gas leaving the evaporator. The thermalexpansion valve maintains a relatively constant degree of superheat in the refrigerant gas leaving theevaporator regardless of suction pressure. Thus, the valve has a dual function: (a) automatic expansioncontrol, and (b) prevention of liquid refrigerant return to compressor.
Poppet valve
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide. In most applications a pressure differential helps to seal the valve and in some applications also open it.
Reductive "self" valve
The invention relates to a reduction valve for mounting on a gas container valve for a bottle for liquified gas comprising an activating spindle which is displaceable for opening of a self-closing valve in the gas container valve by overcoming the bias from the valve spring of the self-closing valve. The invention also relates to a gas container valve for a bottle for liquified gas for connection with a reduction valve, and comprising a self-closing valve which by a valve spring is biased for closing, the self-closing valve being adapted to open by displacement of an activating spindle in the reduction valve by overcoming the bias from the valve spring.
Specific Types
4-stroke cycle engine valves: an application of piston valve
Aspin valve: which consists of a cone-shaped metal part fitted to the cylinder head. Aspin valves were first patented by Frank Metcalf Aspin in 1937 although the idea was probably devised before this time.
A ballcock: is a device which is designed to enable the filling of water tanks without overflow. You may also hear ballcocks referred to as balltaps or fill valves, and the most well-known example of a ballcock is the assembly used in most modern toilets.
Bibcock: provides a connection to a flexible hosepipe
Blast valve: This blast valve is designed and tested to protect an underground shelter from a 100 pound per square inch detonation. Blast valves are mounted on the air intake and air outflow pipes inside a bomb shelter. As a high pressure wave from a nearby detonation passes over the shelter, the pressure travels down the pipes and into the shelter. If this high pressure is not stopped, it will destroy the air filtration equipment and injure or kill the occupants. Directly behind this high pressure wave is a vacuum wave - all of the atmosphere is blown outward from the epicenter of the detonation. This vacuum wave can be as deadly as the pressure wave. That is why these valves are double acting - pressure and vacuum.
Cock: colloquial term for a small valve or a stopcock
Demand valve: The Demand Valve Resuscitator provides a fast, simple, and effective means to ventilate non-breathing patients and provides 100% oxygen to patients suffering from respiratory distress "On Demand". It Provides fast, effective method to ventilate the non-breathing patient. Allows both hands to remain on the mask when depressing the Manual Ventilation Button.
Double Beat Valves: which are used in Sugar Factories in the Juice Heater Section. These Valves are used to allow liquid to flow through Juice Heater or bypass the Juice Heater whenever the particular Juice Heater is on maintenance. These Valves have two ports each toward the bottom and the top. These valves can be closed at the bottom port section or at the top port section. Whenever the valve is closed at the ports section, the juice goes to the Juice Heater, gets heated up and then goes out through the valve. Whenever the valve is closed at the bottom port, the juice goes out directly to the next section without going through the particular Juice Heater.
Double check valve: A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. It consists of two check valves
Duckbill check valves: which Vernay Duckbill Check Valves, widely used in the demanding applications of many industries, are precision-molded, one-piece elastomeric valves that provide reliable backflow prevention at low pressure differentials. Duckbill check valves allow free flow with positive differential pressure. With negative differential pressure, backflow is checked. Pressure drop across the valve is a feature unique to Duckbill Check Valves. They can be designed to operate in a few millimeters (inches) of water to several hundred kPa (psi), depending on valve size, geometry and compound characteristcs. Duckbill Check Valves are also designed to start functioning at specific opening and closing pressure ranges, depending on your specifications.
flow control valve: which regulates the flow or pressure of a fluid. Control valves normally respond to signals generated by independent devices such as flow meters or temperature gauges.
Four-way valve: The four-way valve or four-way cock is a fluid control valve whose body has four ports equally spaced round the valve chamber and the plug has two passages to connect adjacent ports. The plug may be cylindrical or tapered, or a ball.
Freeze valve: in which freezing and melting the fluid creates and removes a plug of frozen material acting as the valve
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 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
Rotary valves and piston valves: parts of brass instruments used to change their pitch
Rupture disc: A rupture disc or bursting disc is a non-reclosing pressure relief device that protects a vessel, equipment or system from overpressurization or potentially damaging vacuum conditions.
A saddle valve: A saddle valveis a valve used to supply liquid where a low volume, low pressure stream is required. The name is derived from the fact that it is mounted in such a way that it "saddles" the line, mounting it from both sides.
Safety valve or relief valve: operates automatically at a set differential pressure to correct a potentially dangerous situation, typically over-pressure
Schrader valve: The Schrader valve (also called American valve)[1] invented by August Schrader in 1891[2] consists of a valve stem into which a valve core is threaded, and is used on virtually all automobile tires and most wider rimmed bicycle tires. The valve core is a poppet valve assisted by a spring.
A solenoid valve: A solenoid valve is an electromechanical valve for use with liquid or gas. The valve is controlled by an electric current through a solenoid coil.
A stopcock: A stopcockis a valve used to restrict or isolate the flow of a liquid or gas through a pipe.
Tap (British English), faucet (American English): the common name for a valve used in homes to regulate water flow
Swirl valve: Swirl valve technology has been developed by Twister BV of the Netherlands primarily for the gas processing market.[1] This technology is similar to the swirl tube[2] and can also be applied for liquid/liquid separation applications such as oil/water separation and for oil degassing.
Thermal expansion valve: A thermostatic expansion valve (often abbreviated as TXV or TX valve) is a component in refrigeration and air conditioning systems that controls the amount of refrigerant flow into the evaporator thereby controling the superheat at the outlet of the evaporator.
Thermostatic Mixing Valve: A Thermostatic Mixing Valve (TMV) is a valve that blends hot water (stored at temperatures high enough to kill bacteria) with cold water to ensure constant, safe outlet temperatures preventing scalding.
Thermostatic Radiator Valve: A Thermostatic Radiator Valve (TRV) is a self-regulating valve fitted to hot water heating system radiators.
Trap primer: sometimes include other types of valves, or are valves themselves
Vacuum breaker valve: An Atmospheric Vacuum Breaker (AVB) is a backflow prevention device used in plumbing to prevent backflow of non-potable liquids into the drinking water system.