An air release valve, automatic air vent, or automatic bleeding valve is a self-acting valve or device that automatically releases or purges trapped air out of the loop of a hot water, cold water or chilled water system, through a float-type vent.

Automatic air vent is installed mainly at the height points of the system, or wherever pockets of air bubbles are expected (heat exchangers, coils, horizontally installed concentric reducers, etc.)

Alarm check valve is a check valve assembly that is used in the wet standpipe fire sprinkler system to prevent backflow and to trigger the water motor gong to indicate a flow in a fire case.

An angle valve is a manually operated where the inlet and outlet ports are at 90◦ (perpendicular) to each other. It is used to control the flow in some applications such as boiler feed water, sanitary supply water, kitchen sink supply water and heater drain service.

An air release valve, automatic air vent, or automatic bleeding valve is a self-acting valve or device that automatically releases or purges trapped air out of the loop of a hot water, cold water or chilled water system, through a float-type vent.

Automatic air vent is installed mainly at the height points of the system, or wherever pockets of air bubbles are expected (heat exchangers, coils, horizontally installed concentric reducers, etc.)

An automatic balancing valve is a dynamic throttling valve that is used to ensure that the design flow rate is achieved at all times irrespective of any pressure changes within the system.

In an ABV, a set constant flow is maintained, within +/- 5% of the designed flow, by a number of cartridges that react against pressure fluctuation by means of their spring loaded mechanism.

When the pressure increases, the spring is compressed and the piston reduces the outlet area to maintain the same flow rate; when differential pressure decreases the spring is uncompressed and the piston return to the normal open position to increase outlet area.

An air release valve, automatic air vent, or automatic bleeding valve is a self-acting valve or device that automatically releases or purges trapped air out of the loop of a hot water, cold water or chilled water system, through a float-type vent.

Automatic air vent is installed mainly at the height points of the system, or wherever pockets of air bubbles are expected (heat exchangers, coils, horizontally installed concentric reducers, etc.)

An Automatic control valve or control valve is an actuated throttling or On/Off valve that regulates the fluid (water, fuel, gas, etc.) flow, and controls the consequential variables including pressure, temperature and fluid level, by changing the cross area of the flow passage (valve orifice). Control valves normally respond to signals generated by devices such as flow meters, temperature gauges or thermostats.

Control valves are fitted with actuators that operate electrically, hydraulically or pneumatically. The body of the control valve can be 2-way (2-port) globe valve and quarter-turn valves (ball and butterfly valves) and 3-way (2-port) rotary shoe valve.

The control valve is the final control element of a process loop (besides a sensing device such as temperature sensor or switch and a controller such as thermostat or DDC).

An automatic expansion valve (AXV) is an expansion valve that is equipped with a pressure-actuated diaphragm or bellows that is attached, from the top with a controlling spring. The torsion of the controlling spring is adjusted by a pressure setting screw. It operates with prefixed constant pressure in the evaporator.

The spring pressure along with the atmospheric pressure, above the diaphragm, will push the diagram down and accordingly the valve needle (attached to the bottom of the diaphragm) will move down away from the valve seat to open the valve. On the other hand, the evaporator pressure, below the diaphragm, will push the diagram up and accordingly the valve needle (attached to the bottom of the diaphragm) will move up toward the valve seat to close the valve.

By achieving equilibrium between the evaporator pressure and the spring pressure, the valve maintains a certain opening to allow the flow of refrigerant through it and hence it automatically maintains a constant pressure inside the evaporator as per the setting of the spring pressure.

Automatic expansion valve (AXV) is less efficient when compared to other expansion valves.

A balancing valve is static or dynamic throttling valve that is used to ensure that the design flow rate is achieved. In the static type, the set design flow can’t be maintained when the pressure in the system fluctuates, while in the dynamic type, the set design flow will remained unchanged at all times irrespective of any pressure changes within the system..

A ball valve is a quarter-turn manual straight-through flow valve that uses a metal ball bored in the center and held between two seats to control flow. A ball valve is a quarter-turn (moves from open to close position within 90° turning). It can be used in gas, vapor and water applications.

A ball check valve is a lift check valve that has a spherical ball instead of the disc used in the swing or wafer check valve. The ball moves up and down inside the valve. The seat is machined to fit the ball, and the chamber is conically shaped to guide the ball into the seat to seal and stop/block a reverse flow. In normal flow direction, the ball will be lifted up when there is enough pressure.

Float valve or ball-cock is a device that admits or discharges a liquid to or from a tank and regulated by a float (ball) on the surface of the liquid within the tank to maintain a nearly constant height of liquid. The float (ball) is attached to a level that moves up or down, along with float based on the liquid level, to close or open the valve, respectively.

A basket strainer is a closed vessel with cleanable and removable screen designed to remove and retain foreign particles and ingredients down to 0.001 inch diameter from various flowing fluids. In comparison with Y-type strainers, basket strainers can be only installed horizontally, they are used for higher flow capacities and thus they can stand lower operating pressure.

A bib tab is a faucet with a nozzle or hose union that is bent downward. Bib tap is used to provide a water supply for garden, parking, roof, garbage, etc. Bib tap is a wall mounted cock that can be connected to the main water pipe by its ½ inch male thread inlet.

A non-rising stem gate valve, rotary stem gate valve or a blind stem wedge gate valve is a valve where the outside stem will turn to open and close the closure element (gate, wedge, etc), but the stem does not move up or down as it turns. Unlike, the rising stem gate valve, the observer can’t distinguish from a distance whether the non-rising stem gate valve is opened or not.

A block valve is a valve that either allows full flow or stops flow completely. It should only be operated in the fully open or fully closed position. Examples of block valves are gate valve, slide valve, butterfly valve, ball valve and plug valve.

Breeching inlet connection or breeching inlet valve is a fitting that have 2-way or 4-way spring loaded inlet connections at one side and 4"(100mm) or 6"(150mm) outlet flange at the other side.

Breeching inlet is installed outside the building in an accessible location at the ground floor to induce water by the fire department personal into the fire standpipe or riser mains to charge-up the dry riser valve or landing valve at each floor.

Breeching inlet connection or breeching inlet valve is a fitting that have 2-way or 4-way spring loaded inlet connections at one side and 4"(100mm) or 6"(150mm) outlet flange at the other side.

Breeching inlet is installed outside the building in an accessible location at the ground floor to induce water by the fire department personal into the fire standpipe or riser mains to charge-up the dry riser valve or landing valve at each floor.

A butterfly valve is a quarter-turn manual or motorized rotary motion valve that blocks or regulates the flow. It has a quarter-turn (0° to 90°) rotating round disk as the closure element. Unlike the gate valve, the butterfly valve is lighter, occupies less space, and needs less force and time to open or close. Also, high-performance butterfly valves offer zero leakage design.

A bypass valve is a valve connecting two main lines, usually fitted in between within a bypass line using branch tees, to divert the total or a portion of the flow from one line to the other.

A bypass valve can be manual and used in maintenance to isolate the downstream valves or the valves fitted between two sets of bypass valves (e.g. PRV Station).

A bypass valve can be motorized and used to reduce the differential pressure between two main lines (e.g. decoupler line in the chilled water primary-secondary pumping scheme).

A capillary tube is the simplest type of expansion valve that provides a passive control of the refrigerant pressure. It’s a fixed system with no moving part that does not fluctuate with load changes. Therefore, the refrigerant amount should be calibrated properly at the factory level.

Capillary tube is a copper tube of diameter 0.5 to 2.0 mm and length 1.0 to 6.0 m.

When the high pressure refrigerant liquid, coming from the condenser, passes through this long and narrow tube, the refrigerant will expand into a low pressure mixture of liquid and gas which will boil at lower temperature when passing through the evaporator.

A check valve, non return valve, one-way valve, reflux valve, or retention valve is a self-acting backflow prevention device that is designed to allow the fluid to flow in one direction only and prevents the backflow in the other direction.

Main types of check valves are: Swing Check Valve, Non-Slam Check Valve (Swing with Spring), Lift Check Valve (Ball, Piston, and Poppet), Wafer/Butterfly Check Valve (Disk, Duo-Check, Double Door, and Dual Plate), Tilting-Disc and Stop Check Valve.

A Chain wheel valve is a large gear operated large butterfly valve or ball valve that is installed at an elevated position where it is not possible to access them easily, erect a platform or add a ladder.

An Automatic control valve or control valve is an actuated throttling or On/Off valve that regulates the fluid (water, fuel, gas, etc.) flow, and controls the consequential variables including pressure, temperature and fluid level, by changing the cross area of the flow passage (valve orifice). Control valves normally respond to signals generated by devices such as flow meters, temperature gauges or thermostats.

Control valves are fitted with actuators that operate electrically, hydraulically or pneumatically. The body of the control valve can be 2-way (2-port) globe valve and quarter-turn valves (ball and butterfly valves) and 3-way (2-port) rotary shoe valve.

The control valve is the final control element of a process loop (besides a sensing device such as temperature sensor or switch and a controller such as thermostat or DDC).

A cryogenic valve is a valve designed for cryogenic applications such as liquefied industrial gases and other media with temperatures below -40 degrees Celsius.

A deluge valve is a hydraulically operated diaphragm valve that is used to deliver, in a short period of time, huge quantities of water, with or without foam, over large areas or high hazardous areas where fires can spread rapidly (e.g. chemical storage, transformers).

Deluge valve is used in fire suppression systems where downstream pipe is dry (empty) until the deluge valve is actuated by a fire detection system installed in the same areas as the spray nozzles or remote manual operation to distribute pressurized water from open nozzles or sprinklers over the area where the fire has been detected.

A diaphragm valve or membrane valve is a bi-directional linear motion valve that uses a flexible disk (i.e. elastomeric diaphragm or rubber membrane) to start/stop or regulate fluid flow.

Diaphragm valve types are mainly straight through diaphragm valve and weir diaphragm valve, and the controlling actuators can include manual, electric, pneumatic, and hydraulic.

Diaphragm valve may be used in hygienic applications, high viscous liquids (e.g. slurries) where other valves might clog and wherever the application requires that the flow stream to be separated from the closure element (Ball, gate, plug, clapper, disc, wedge, etc) or tight shutoff (no leakage).

A digital control valve is an electrically actuated, hydraulically operated, by diaphragm self fluid actuated type, that is used for many functions.

It consists of diaphragm operated Y-pattern design globe valve, and two solenoid valves (first one normally open (N/O) at the inlet and the second one normally closed (N/C) at the outlet of the diaphragm) that control the bypass flow between the main valve and the hydraulic diaphragm which will respond to the pressure changes and consequently will open or close the main valve to maintain the design flow as required.

A digital mixing valve is used in heating application to remotely regulate and control water temperatures on the supply side of the distribution system (domestic hot water supply system, radiant floor heating system, etc.) by mixing between the hot water and the cold water to maintain a specific temperature set point .

A digital mixing valve is used when a domestic hot water system has a recirculation pump (i.e. continuously pumped circulating hot water system) to provides enhanced water temperature control accuracy which resists zero system demand when there is no draw from fixtures at night or at the early morning to prevent the overheated (temperature creep) or underheated (temperature droop) hot water when the system is not properly piped, without the use of a manual throttling valve or a temperature activated pump shut-off device.

A differential pressure control valve is a valve that can control the pressure difference between the upstream and the downstream ports of a valve (delta P). DPCV is used to eliminate the pressure fluctuation in the system to maintain constant design flow preset by a balancing valve.

The differential pressure control valve is usually used along with a balancing valve that does not have the pressure fluctuation elimination feature, such as a double regulating valve (DRV).

A diverter valve is a valve that can change the direction of the fluid flow to two or more different directions.

A diverting control valve is a 2-port (2-way) 2-position modulating control valve that diverts the total flow diverted either one way or the other.

In chilled water or hot water application, the diverting control valve diverts the water flow totally to the return when the demand is achieved (i.e. served space temperature is either equal or close to the set point). 2-Port Control valves are used when the pumps are VFD controlled.

A double block and bleed valve is a device that combines between two block valves and one intermediate bleed valve. Closure of the tightly sealed seats of the two block valves should provide positive isolation against fluid flow from both directions and prevention against leaks at any side, while the bleed valve will drain or vent any excess medium.

DBB valves are resistant to vibration and pressure shock waves, and mainly used in the repair and maintenance procedures of the critical and high pressure live process services including oil, and gas, petrochemical, cryogenic, storage, and transmission industries.

A double check valve, double disc check valve or split disc check valve is a check valve with two discs that are hinged together, fold together when the flow is in the correct direction and swing closed together when the flow is reversed.

Double check valve is suitable for prevention of back pressure and back siphonage.

A double check valve, double disc check valve or split disc check valve is a check valve with two discs that are hinged together, fold together when the flow is in the correct direction and swing closed together when the flow is reversed.

Double check valve is suitable for prevention of back pressure and back siphonage.

A double regulation valve is a static balancing valve that can be used in chilled, cold and hot water systems to regulate both flow and pressure. Because of the static design of the orifice, the design flow can’t be maintained under if the network pressure fluctuates. For that reason, a differential pressure control valve (DPCV) might be need especially in variable flow systems.

A drain cock is a tap or a valve used to draw off a liquid, water oil or fuel, from the lowest part of a water system, cooling unit, tank, boiler, etc.

A dry riser valve is a landing valve installed only on dry fire standpipe or riser mains of a building at the each level of the staircase landing. Dry riser valve is used to provide an easy accessibility for the firefighters to extinguish the fire at each floor of the building.

An electronic expansion valve (AXV) is an expansion valve that is equipped with a permanent magnet stepper motor that changes the valve position, by moving the valve needle to allow or throttle the refrigerant mass flow, based on the command signal received from the controller.

The controller receives feedback signal from a pressure transducer, a temperature sensor or a thermistor sets at the evaporator outlet, and consequently sends electrical signals to the stepper motor to energize the coils and create an electromagnetic field so that the permanent magnet will rotate and the valve needle will move in either upward or downward direction.

Electronic expansion valve is the most efficient when compared to other expansion valves.

An expansion valve is a device with passive orifice that sets just before the evaporator in a vapor-compression cycle. It holds back the high pressure liquid refrigerant from the condenser and decreases the pressure to allow expansion of the refrigerant into a low pressure mixture of liquid and gas which will boil at lower temperature when passing through the evaporator.

Types of expansion valves are capillary tube, automatic expansion valve, electronic expansion valve, hand expansion valve (manual expansion valve) and thermostatic expansion valve.

A fixed orifice double reregulating valve is a static balancing valve that has both test points at the inlet of the valve orifice. Pre-sizing can be done using the flow measurement graphs provided specifically by the manufacturer for each model/side.

Float valve or ball-cock is a device that admits or discharges a liquid to or from a tank and regulated by a float (ball) on the surface of the liquid within the tank to maintain a nearly constant height of liquid. The float (ball) is attached to a level that moves up or down, along with float based on the liquid level, to close or open the valve, respectively.

A foot valve is a backflow prevention device that is equipped with a strainer or screen at the free inlet side, and is usually used inside a water tank at the suction line of water pumps.

A gate valve is a bi-directional multi-turn linear motion block valve used to start or stop a flow completely. Gate valve should not be used to control the flow rate (i.e. by throttling) as partial open position can damage the valve due to the erosion of the seat and disk so that it will not seal well anymore. Gate vale can be classified in terms of the following types:

Stem: Non-Rising Stem and Rising Stem or OS & Y (Outside Stem and Screw)

Closing Element: Parallel disk (e.g. knife), solid/single wedge, flexible wedge, split wedge.

Body Bonnet Joint: Screwed Bonnet, Bolted-Bonnet, Welded-Bonnet and Pressure-Seal Bonnet.

A gearbox valve or gear operated valve is a large butterfly valve or ball valve that is equipped with a handwheel that can be rotated manually or by a chain wrapped around a semicircle section of the handwheel and used as a pulley to turn the stem. In the latter case, it will be called chain wheel valve.

A gearbox valve or gear operated valve is a large butterfly valve or ball valve that is equipped with a handwheel that can be rotated manually or by a chain wrapped around a semicircle section of the handwheel and used as a pulley to turn the stem. In the latter case, it will be called chain wheel valve.

A globe valve is a multi-turn linear-motion valve that is designed to regulate the fluid flow rate by operating partially opened. Unlike the gate valve which can be either with rising stem above the handwheel or non-rising stem where the stem rotates without elevating the wheel, the stem in globe valves is fixed to the wheel and both are rising together when opening the valve.

Globe valve is designed in a straight pattern, 45 deg. Y pattern and 60 deg. Y pattern. It is used for both on–off and throttling applications. The geometry of the globe valve is used in some balancing valve such as the double regulating valves (DRV).

A hand expansion valve or manual expansion valve is a manual throttling or flow regulating valve used for metering or flashing expansion of liquid refrigerants in specific applications including ammonia, halocarbons, fluorocarbons, nitrogen, and carbon dioxide.

A knife gate valve is a gate valve with a knife shaped closure element sliding between two sealing rings. Knife gate valves are used mainly for on/off and isolation services in systems with high content of suspended solids, and slurry, viscous, corrosive and abrasive media.

A landing valve is a valve installed on wet or dry fire standpipe or riser mains of a building at the each level of the staircase landing. Landing valve is used to provide an easy accessibility for the firefighters to extinguish the fire at each floor of the building.

A lift check valve or piston check valve is a check valve that prevents flow reversal by having a free floating element, a ball, a piston, a poppet or a plug (disk). When the check valve is under high pressure from the inlet or the downstream fluid, the floating element off its seat will be lifted up to allow the fluid flowing to the outlet or downstream side. A guide keeps motion of the floating element on a vertical line, so the valve will reseat properly when there is not enough pressure from the inlet side.

A linear valve or multi-turn valve is a valve where the actuator (handwheel, lever, etc.) can be turned more than 360 degree to slide to the stem multiple turns to push the closure element (disk, wedge, plus, etc.) move the valve from the fully open to the fully closed position and vice versa.

Examples of linear or multi-turn valves are gate, globe and needle valves.

Lockshield valve is an isolating valve (e.g. gate valve) with actuator (handwheel, handle, level, etc.) removed to prevent accidental change in the opening/closing position.

In hot water radiators application, a lockshield valve is the valve on a radiator inlet that is covered with a plastic cap and can be adjusted to balance the hot water distribution between the hot water radiators installed in individual space to ensure they all heat up at the same rate.

A manual valve is a valve that is worked by manual operation, such as a handwheel or a lever.

A hand expansion valve or manual expansion valve is a manual throttling or flow regulating valve used for metering or flashing expansion of liquid refrigerants in specific applications including ammonia, halocarbons, fluorocarbons, nitrogen, and carbon dioxide.

A diaphragm valve or membrane valve is a bi-directional linear motion valve that uses a flexible disk (i.e. elastomeric diaphragm or rubber membrane) to start/stop or regulate fluid flow.

Diaphragm valve types are mainly straight through diaphragm valve and weir diaphragm valve, and the controlling actuators can include manual, electric, pneumatic, and hydraulic.

Diaphragm valve may be used in hygienic applications, high viscous liquids (e.g. slurries) where other valves might clog and wherever the application requires that the flow stream to be separated from the closure element (Ball, gate, plug, clapper, disc, wedge, etc) or tight shutoff (no leakage).

A mixing control valve is a 3-port modulating control valve that mixes partially between the supply flow and the return flow to regulate the temperature of the cold water or hot water that feed a load (e.g. AHU’s, FCU’s, Radiators. etc.) according to the temperature setpoint. Mixing Control Valves are used when the pumps are not VFD controlled.

A modulating control valve is a control valve that modulates either the direction of the water flow (diverting 3-port control valve), the direction and distribution of the water flow (mixing 3-port control valve) or quantity of the water flow (modulating 2-port control valve) as a response to the cooling or heating demand (i.e. served space temperature is either equal or close to the set point).

A motorized valve is a valve that uses an actuator driven by an electric motor to open or close its orifice as a response to a programmed control signal or remote override by an operator.

A linear valve or multi-turn valve is a valve where the actuator (handwheel, lever, etc.) can be turned more than 360 degree to slide to the stem multiple turns to push the closure element (disk, wedge, plus, etc.) move the valve from the fully open to the fully closed position and vice versa.

Examples of linear or multi-turn valves are gate, globe and needle valves.

Needle valve is a multi-turn valve that derives its name from the needle shaped closing element. Available in small sizes and used to regulate gas or water, through an appliance or system

A check valve, non return valve, one-way valve, reflux valve, or retention valve is a self-acting backflow prevention device that is designed to allow the fluid to flow in one direction only and prevents the backflow in the other direction.

Main types of check valves are: Swing Check Valve, Non-Slam Check Valve (Swing with Spring), Lift Check Valve (Ball, Piston, and Poppet), Wafer/Butterfly Check Valve (Disk, Duo-Check, Double Door, and Dual Plate), Tilting-Disc and Stop Check Valve.

A non-rising stem gate valve, rotary stem gate valve or a blind stem wedge gate valve is a valve where the outside stem will turn to open and close the closure element (gate, wedge, etc), but the stem does not move up or down as it turns. Unlike, the rising stem gate valve, the observer can’t distinguish from a distance whether the non-rising stem gate valve is opened or not.

A check valve, non return valve, one-way valve, reflux valve, or retention valve is a self-acting backflow prevention device that is designed to allow the fluid to flow in one direction only and prevents the backflow in the other direction.

Main types of check valves are: Swing Check Valve, Non-Slam Check Valve (Swing with Spring), Lift Check Valve (Ball, Piston, and Poppet), Wafer/Butterfly Check Valve (Disk, Duo-Check, Double Door, and Dual Plate), Tilting-Disc and Stop Check Valve.

An on/off control valve is a 2-port control valve that stops completely the supply water flow when the cooling or heating demand is achieved (i.e. served space temperature is either equal or close to the set point). On/Off Control valves are used when the pumps are VFD controlled.

OS&Y gate valve stands for outside stem and yoke or outside screw and yoke. OS&Y is a rising stem gate valve where the closure elements (gate) lowers into or rises out of the valve to show remotely the position of the valve. OS&Y is used in Fire Fighting / Fire Protection applications.on/off control valve is a 2-port control valve that stops completely the supply water flow when the cooling or heating demand is achieved (i.e. served space temperature is either equal or close to the set point). On/Off Control valves are used when the pumps are VFD controlled.

A parallel gate valve, parallel slide gate valve, penstock valve, slide gate valve, or sluice valve is a gate valve with a flat disc shaped closure element sliding between two sealing parallel free floating seat rings.

Parallel slide gate valves are used to provide isolation and transmission of flow in a piping system in applications such as the petroleum and natural gas.

A parallel gate valve, parallel slide gate valve, penstock valve, slide gate valve, or sluice valve is a gate valve with a flat disc shaped closure element sliding between two sealing parallel free floating seat rings.

Parallel slide gate valves are used to provide isolation and transmission of flow in a piping system in applications such as the petroleum and natural gas.

Pilot-operated relief valve (PORV) is a large main pressure relieve valve operated by a small pilot valve. In the main valve, the spring is replaced with a piston or disk that moves vertically up or down according to the pressure balance between the dome (volume above the piston) and the main valve inlet (upstream of main valve seat under the piston).

This pressure balance is created by a small tube called pilot supply line which pickups the internal pressure from the main valve inlet to the dome, and since the dome area is larger than that of the main valve inlet, the result is a larger force on the dome side than the upstream side. This produces a net sealing force and the piston will close the main relief valve.

The pressure at which the small pilot valves relieve at is the functional set pressure of the PORV. When the small pilot valve reaches set pressure, or crosses a threshold, it opens and releases the pressure from the dome. The piston is then free to open and the main valve exhausts the system fluid. The small pilot valve opens either to the main valve exhaust pipe or to atmosphere.

Pilot-operated relief valve (PORV) is also known as pilot- operated pressure relief valve (POPRV), pilot-operated safety valve (POSV), and pilot-operated safety relief valve (POSRV).

Pilot valve is a small valve that is used to operate a larger valve like a pilot-operated relief valve. Pilot valve functional pressure is set by an adjustment screw, otherwise it’s solenoid operated.

Pinch Valve is a full bore linear motion valve that is used to start, stop or regulate the flow of corrosive, abrasive or granular media. This valve is often used in slurry and mining applications, as its operation is not affected by solid matter in the medium.

A lift check valve or piston check valve is a check valve that prevents flow reversal by having a free floating element, a ball, a piston, a poppet or a plug (disk). When the check valve is under high pressure from the inlet or the downstream fluid, the floating element off its seat will be lifted up to allow the fluid flowing to the outlet or downstream side. A guide keeps motion of the floating element on a vertical line, so the valve will reseat properly when there is not enough pressure from the inlet side.

A plug valve is a full-port quarter-turn (rotary motion) valve which uses a cylindrical or tapered plug shaped disk to start, stop or regulate the gas or fluid flow. When the plug is turned 90° from the open position, the solid part of the plug blocks the flow. Plug valve is used as quick operation block or isolating valve. It can be used in high-pressure temperature services.

Post indicator valve (PIV) is a free standing isolating valve (e.g. gate) installed in the water supply main line to control the water supply to the domestic water, fire suppression system, fire sprinkler system or fire hydrants. Post indicator valve (PIV) is mounted vertically outside the building.

Preaction Valve / Pre-Acting Valve is an automatic electrically operated valve that used in the automatic sprinkler systems to keep the downstream piping dry (e.g. filled with air or nitrogen) till a signal is received from the Fire Alarm Control Panel. This valve is used so that the protected sensitive areas will not be exposed to water in case of accidental break of the sprinklers without fire breaking out. Also it can be used to protect freezing areas such as refrigeration installations.

A pressure independent control valve (PICV) is a dynamic control and balancing valve that is equipped with an actuator (e.g. electrical) to change the orifice opening as response to the system pressure fluctuations to maintain a fixed design flow. A PICV combines the functions of control valve, balancing valve and differential pressure control valve.

A pressure reducing valve, pressure regulating valve, safety valve or safety relief valve is a valve used to reduce to drop with pressure, with maintaining the same flow, to protect the downstream elements of the system such as bathroom taps from excessive pressure.

The opening and closing of the valve is based on the outlet pressure and is controlled by a spring (loaded by a adjusting screw) attached to a diaphragm, diaphragm is moving along with the valve stem and disk upward and downward according to the outlet pressure.

When the outlet pressure at the bottom of the diaphragm increases, approaches the design pressure and overcomes the spring pressure (higher than the setpoint), the outlet pressure of the valve forces the diaphragm upward, toward the seat, to shut the valve.

When the outlet pressure at the bottom of the diaphragm decreases and drops below the set point of the valve, the spring pressure overcomes the outlet pressure and forces the valve stem and disk downward, away from the seat, to open the valve.

A pressure reducing valve, pressure regulating valve, safety valve or safety relief valve is a valve used to reduce to drop with pressure, with maintaining the same flow, to protect the downstream elements of the system such as bathroom taps from excessive pressure.

The opening and closing of the valve is based on the outlet pressure and is controlled by a spring (loaded by a adjusting screw) attached to a diaphragm, diaphragm is moving along with the valve stem and disk upward and downward according to the outlet pressure.

When the outlet pressure at the bottom of the diaphragm increases, approaches the design pressure and overcomes the spring pressure (higher than the setpoint), the outlet pressure of the valve forces the diaphragm upward, toward the seat, to shut the valve.

When the outlet pressure at the bottom of the diaphragm decreases and drops below the set point of the valve, the spring pressure overcomes the outlet pressure and forces the valve stem and disk downward, away from the seat, to open the valve.

A pressure relief valve is a device used to protect a hot water system, steam system, compressed air system or a vessel against damage due to excessive pressure by relieving over-pressurization pressure of these systems or equipment at a pre-determined setpoint pressure. PRV is held closed by a spring that presses a disk or piston on a seat, which will be forced to open if the applicable system pressure is greater than the mechanical value of the spring.

Unlike the rapid action and full opening of the safety valve, a relief valve opens as necessary and gradually as the inlet pressure increases above the setpoint to relieve the over-pressure condition.

A pressure safety valve is fail-safe device that can have the same definition of a pressure relief valve except that it’s used also as the last resort to protect more critical systems including power plants, petrochemicals, boilers, oil and gas, and pharmaceuticals, its actuation response is rapid, it opens full and trips automatically to let go excess pressure and prevent the damage due to the accumulation of pressure in a vessel, equipment or system beyond a preset limit. The safety valve closes as soon as the pressure is reduced to the prescribed limit. In summary, it has a swift action.

A quarter-turn valve or rotary valve is a valve that moves from open to close position within 90° turning). Examples of quarter-turn valves are ball valves, plug valves, and butterfly valves.

A radiator air vent is an automatic bleeding valve or air release valve that is used to release the air bubble trapped within a radiator to allow hot water circulates fully in the upper part of a radiator and hence the heating power of the radiator is increased.

A check valve, non return valve, one-way valve, reflux valve, or retention valve is a self-acting backflow prevention device that is designed to allow the fluid to flow in one direction only and prevents the backflow in the other direction.

Main types of check valves are: Swing Check Valve, Non-Slam Check Valve (Swing with Spring), Lift Check Valve (Ball, Piston, and Poppet), Wafer/Butterfly Check Valve (Disk, Duo-Check, Double Door, and Dual Plate), Tilting-Disc and Stop Check Valve.

A regulating valve is valve type used to regulate flows to provide a constant pressure output.

A resilient wedge gate valve (RWGV) is a gate valve with a closure element (wedge) that is fully rubber-sealed. This design prevents the embedding and buildup of sand and sediment, and preserves sealing capability, and interior coating integrity for a long usual reliable operation.

Resilient wedge gate valve can be available in different designs such as non-rising stem (NRS) post indicator valve (PIV), non-rising stem with stuffing box, and outside screw and yoke (OS&Y) with handwheel. RWGV is used in drinking water, sewage, irrigation and fire protection systems

A check valve, non return valve, one-way valve, reflux valve, or retention valve is a self-acting backflow prevention device that is designed to allow the fluid to flow in one direction only and prevents the backflow in the other direction.

Main types of check valves are: Swing Check Valve, Non-Slam Check Valve (Swing with Spring), Lift Check Valve (Ball, Piston, and Poppet), Wafer/Butterfly Check Valve (Disk, Duo-Check, Double Door, and Dual Plate), Tilting-Disc and Stop Check Valve.

A rising stem gate valve is a valve where the stem, which is threaded and mated with the bushing threads of a yoke right under the hand wheel, will rise above the hand wheel as the valve opens. This type of valves helps the observer easily distinguishing from a distance whether the valve is opened or not. Usually this valve is used critical application such as fight protection.

A quarter-turn valve or rotary valve is a valve that moves from open to close position within 90° turning). Examples of quarter-turn valves are ball valves, plug valves, and butterfly valves.

A non-rising stem gate valve, rotary stem gate valve or a blind stem wedge gate valve is a valve where the outside stem will turn to open and close the closure element (gate, wedge, etc), but the stem does not move up or down as it turns. Unlike, the rising stem gate valve, the observer can’t distinguish from a distance whether the non-rising stem gate valve is opened or not.

A tank valve is a drain valve fitted at the bottom or lowest point of a tank or process vessel, to allow full draining, cleaning or sterilizing of the tank. Tank valve is usually manually operated.

Thermal balancing valves are valve that are used in circulating hot water systems. The balancing valve regulates the flow of water based on the temperature. Once the water temperature rises to its set point (60°C, 70°C, etc.) the thermal balancing valve restricts the flow.

Thermal balancing valves (TBV) are Two-Way valves.

A thermostatic mixing valve is a valve that mixes between hot water and cold water to ensure constant and safe outlet temperature at the water heater, calorifier and the point of delivery to the fixture of shower and bath, preventing scalding and growth of Legionella.

Thermal mixing valves (MBV) are Three-Way valves.

A thermostatic radiator valve is a self-regulating valve fitted to hot water heating system radiator; it measures the temperature in the room and then adapts the heat output of the radiator by changing the flow of hot water to the radiator. When the room temperature reaches the desired level, the valve closes to stop the flow of water and prevent the radiator from getting any hotter.

A throttle valve is a valve designed to open or close partially to regulate the fluid flow by creating a pressure drop across the valve. Examples of throttle valves: globe valves, butterfly valves, diaphragm valves and needle valves.

Tilting disc check valve is a valve similar to the swing check valve. However, since the tilting disc check valve fluctuates between 60% and 84%, while the opening of the swing check valve is 94%, the tilting check disc check valve can be used in both horizontal and vertical installation without the potentiality that the disc will gets stuck in the opening position in case of vertical installation.

Tilting disc check valve can be fitted with an external lever and weight if the reverse flow pressure is insufficient to cause a tight seal between the disc and the seat.

A trunnion mounted ball valve is a quarter-turn valve in which the closure element is a hollow, fixed/supported and rotating ball that is used to start, stop and regulate the fluid flow through it.

TMBV ball is supported at the base by a shaft. This valve is more common on larger pipe sizes and higher pressure ratings because of the weight of the ball.

A two-way control valve is a control valve that controls the flow rate of a fluid either by partial closure (modulating type 2-port control valve) or full closure (On/Off type 2-port control valve) as a response to the control demand signal (e.g. served space temperature is either equal or less than the set point). 2-port control valves are usually used when the pumps are VFD controlled.

A 3-way control valve is a modulating control valve that either modulates the direction of the fluid flow (diverting 3-port control valve), or modulates both of the direction and flow rate of the fluid (mixing 3-port control valve) as a response a control demand signal (e.g. served space temperature is either equal or less than the set point). 3-port control valves are usually used when the pumps are not VFD controlled.

A though-conduit gate valve is a full-bore gate valve with a flow resistance coefficient equal to that of the piping (very low pressure drop). Because of the full-bore design, these valves allow for the passage of pipeline pigs or scrapers for cleaning, de-watering, batching, etc.

A pressure reducing valve, pressure regulating valve, safety valve or safety relief valve is a valve used to reduce to drop with pressure, with maintaining the same flow, to protect the downstream elements of the system such as bathroom taps from excessive pressure.

The opening and closing of the valve is based on the outlet pressure and is controlled by a spring (loaded by a adjusting screw) attached to a diaphragm, diaphragm is moving along with the valve stem and disk upward and downward according to the outlet pressure.

When the outlet pressure at the bottom of the diaphragm increases, approaches the design pressure and overcomes the spring pressure (higher than the setpoint), the outlet pressure of the valve forces the diaphragm upward, toward the seat, to shut the valve.

When the outlet pressure at the bottom of the diaphragm decreases and drops below the set point of the valve, the spring pressure overcomes the outlet pressure and forces the valve stem and disk downward, away from the seat, to open the valve.

A sampling valve is a non-inline valve that is fitted to a tank, pipeline or reactor to extract sample (for testing) from or inject product into. The setback of this valve is that inappropriate installation or use may result in spillage or leakage.

Shut-Off Valve, Safety Shut-Off Valve, Shutdown Valve (SDV), Emergency Safety Valve (ESV), and Emergency Shutdown Valve (ESDV) is a an emergency block valve that is designed to fully stop the flow of a fluid in hazardous applications and processes (e.g. compressed air, flammable fluids, chemical liquids) to protect the operators, systems and equipment.

A single block and bleed valve is a device that combines between one block valve and one bleed valve. Closure of the tightly sealed seat of the two block valve should provide positive isolation against fluid flow from one directions and prevention against leaks at the side of that direction, while the bleed valve will drain or vent any excess medium.

SBB valves are usually used in the repair and maintenance procedures of the non-critical, non-hazardous, non toxic, non hydrocarbon and low pressure live process services

A parallel gate valve, parallel slide gate valve, penstock valve, slide gate valve, or sluice valve is a gate valve with a flat disc shaped closure element sliding between two sealing parallel free floating seat rings.

Parallel slide gate valves are used to provide isolation and transmission of flow in a piping system in applications such as the petroleum and natural gas.

A parallel gate valve, parallel slide gate valve, penstock valve, slide gate valve, or sluice valve is a gate valve with a flat disc shaped closure element sliding between two sealing parallel free floating seat rings.

Parallel slide gate valves are used to provide isolation and transmission of flow in a piping system in applications such as the petroleum and natural gas.

A solenoid valve is an electrically controlled valve with a solenoid (an electric coil made of many turns of tightly wound copper wire) attached to a movable ferromagnetic core (plunger or piston) in its center. In the rest position, the plunger closes off a small orifice by the force of the coil. When energized, an electric current will flow through the coil and built up a magnetic field or flux which will pull the plunger (piston) against the action of a spring (coil).

Solenoid valve is used as automatic flow control device in many pneumatic and hydraulic systems including air compressors, DX units refrigeration, irrigation and automobiles.

A double check valve, double disc check valve or split disc check valve is a check valve with two discs that are hinged together, fold together when the flow is in the correct direction and swing closed together when the flow is reversed.

Double check valve is suitable for prevention of back pressure and back siphonage.

A stop check valve is a combination of a lift check valve and a globe valve. The glove valve part is used as an override control to stop flow regardless of flow direction or pressure. When the stem is operated to the open position, the valve operates as a lift check. When the stem is operated to the close position, the closure element (disk) seals the seat and flow is stopped.

A strainer is a device or vessel equipped with a holes punched or crossed wires filter for separating solid matter and particles down to particular size, based on efficiency, from a liquid.

General types of strainer are Y-Strainer, Basket Strainer and Suction Diffuser.

A subsea valve is a valve that is designed for use in seawater and used to isolate or control the flow of the fluid in a undersea (submarine) pipeline. Typical applications are oil and gas.

A suction diffuser is one of the strainer types used at the suction side of pump (usually the single suction pump or end-suction pump) to replace the strainer, the elbow and the reducer between the pump and the suction header. That’s to say, a suction diffuser is a combination of strainer, elbow, reducer, and straightening vane (straightening vane has two functions; to prevent the swirling action of water coming out of the elbow and to diffuse the water into the pump).

Supervisory switch butterfly valve or tamper switch butterfly valve is a control valve installed in the automatic sprinkler system and is equipped with a supervisory switch (tamper switch) which is a safety device used to detect if any fire sprinkler control valve is closed and send a signal to the Fire Alarm Control Panel (FACP) or sound a local alarm to warn the operator(s) about this fault.

A swing check valve is a check valve that prevents flow reversal by having a disc that swings on a hinge or shaft. When the check valve is under high pressure from the inlet or the downstream fluid, the disk will swing away from its seat to allow the fluid flowing to the outlet or downstream side. The check valve is under high pressure from the outlet side (reversal flow), the disk swings to the closed position (toward the seat) to prevent the backflow.

Supervisory switch butterfly valve or tamper switch butterfly valve is a control valve installed in the automatic sprinkler system and is equipped with a supervisory switch (tamper switch) which is a safety device used to detect if any fire sprinkler control valve is closed and send a signal to the Fire Alarm Control Panel (FACP) or sound a local alarm to warn the operator(s) about this fault.

A tank valve is a drain valve fitted at the bottom or lowest point of a tank or process vessel, to allow full draining, cleaning or sterilizing of the tank. Tank valve is usually manually operated

A thermal expansion valve or thermostatic expansion valve (abbreviated as TEV, TXV, or TX) is a mechanical expansion valve that is equipped with a membrane (diaphragm) inside the valve housing, and is also combined with a capillary tube and sensing thermal bulb that is located the outlet of the evaporator to regulate the superheat of the refrigerant vapor leaving the evaporator by comparing the temperatures/ pressures before and after the evaporator.

The movement of the membrane (diaphragm) controls the position of the internal valve needle, up or down, away from or toward the valve seat, respectively, and hence controls the flow of refrigerant entering the evaporator. Superheat set point can be adjusted by a screw or stem that change the tension of a controlling spring attached to the needle valve from the bottom.

A thermal expansion valve or thermostatic expansion valve (abbreviated as TEV, TXV, or TX) is a mechanical expansion valve that is equipped with a membrane (diaphragm) inside the valve housing, and is also combined with a capillary tube and sensing thermal bulb that is located the outlet of the evaporator to regulate the superheat of the refrigerant vapor leaving the evaporator by comparing the temperatures/ pressures before and after the evaporator.

The movement of the membrane (diaphragm) controls the position of the internal valve needle, up or down, away from or toward the valve seat, respectively, and hence controls the flow of refrigerant entering the evaporator. Superheat set point can be adjusted by a screw or stem that change the tension of a controlling spring attached to the needle valve from the bottom

Thermal balancing valves is a 2-Way valve that are used in circulating hot water systems. The balancing valve regulates the flow of water based on the temperature. Once the water temperature rises to its set point (60°C, 70°C, etc.) the thermal balancing valve restricts the flow.

A thermostatic mixing valve is a 3-way valve that mixes between hot water and cold water to ensure constant and safe outlet temperature at the water heater, calorifier and the point of delivery to the fixture of shower and bath, preventing scalding and growth of Legionella.

A thermostatic radiator valve is a self-regulating valve fitted to hot water heating system radiator; it measures the temperature in the room and then adapts the heat output of the radiator by changing the flow of hot water to the radiator. When the room temperature reaches the desired level, the valve closes to stop the flow of water and prevent the radiator from getting any hotter.

A throttle valve is a valve designed to open or close partially to regulate the fluid flow by creating a pressure drop across the valve. Examples of throttle valves: globe valves, butterfly valves, diaphragm valves and needle valves.

Tilting disc check valve is a valve similar to the swing check valve. However, since the tilting disc check valve fluctuates between 60% and 84%, while the opening of the swing check valve is 94%, the tilting check disc check valve can be used in both horizontal and vertical installation without the potentiality that the disc will gets stuck in the opening position in case of vertical installation.

Tilting disc check valve can be fitted with an external lever and weight if the reverse flow pressure is insufficient to cause a tight seal between the disc and the seat.

A trunnion mounted ball valve is a quarter-turn valve in which the closure element is a hollow, fixed/supported and rotating ball that is used to start, stop and regulate the fluid flow through it.

TMBV ball is supported at the base by a shaft. This valve is more common on larger pipe sizes and higher pressure ratings because of the weight of the ball..

A two-way control valve is a control valve that controls the flow rate of a fluid either by partial closure (modulating type 2-port control valve) or full closure (On/Off type 2-port control valve) as a response to the control demand signal (e.g. served space temperature is either equal or less than the set point). 2-port control valves are usually used when the pumps are VFD controlled.

A 3-way control valve is a modulating control valve that either modulates the direction of the fluid flow (diverting 3-port control valve), or modulates both of the direction and flow rate of the fluid (mixing 3-port control valve) as a response a control demand signal (e.g. served space temperature is either equal or less than the set point). 3-port control valves are usually used when the pumps are not VFD controlled.

A though-conduit gate valve is a full-bore gate valve with a flow resistance coefficient equal to that of the piping (very low pressure drop). Because of the full-bore design, these valves allow for the passage of pipeline pigs or scrapers for cleaning, de-watering, batching, etc.

UL FM Valve is any valve that is listed by UL (Underwriters Laboratory) and approved by FM (Factory Mutual). UL listing and FM approval is mainly required for Fire Protection Valves.

A variable orifice double regulating valve is a static balancing valve that has two test points, one test point upstream of the orifice and the other one downstream of the orifice. Pre-sizing is more difficult than that of the FODRV as the residual pressure at each VODRV should be calculated to be used as one of the inputs in the sizing software provided by the valve’s manufacturer.

A wafer check valve is a flangeless single or dual plate check valve. It is made to fit in tight spaces between two flanges and used in applications that require valves with short takeout lengths.

Wall Post indicator valve (WPIV) is a wall mounted isolating valve (e.g. gate) installed in the water supply main line to control the water supply to the domestic water, fire suppression system, fire sprinkler system or fire hydrants. WPIV is attached horizontally to the building.

A wedge gate valve is a gate valve with a wedge shaped closure element that seats against two inclined seats. Wedge gate valves are used mainly in high flow, vibrating, chattering or turbulent applications such as steam systems.

A wellhead valve is a valve used to isolate the flow of oil or gas at the takeoff from oil or gas well. The design is usually a plug or gate valve, inline or angle pattern.

A Y-strainer is a closed vessel with cleanable and removable screen, 45 or 60 degree Y- shaped and designed to remove and retain foreign particles and ingredients from various flowing fluids.

Y pattern strainers are mainly installed horizontally, but can also be installed vertically with less efficiency. Strainer mesh hole diameter varies proportionally based on the strainer size. Typical mesh hole diameters are 0.75 mm, 1.4 mm, 1.5 mm and 3.0 mm.

Zone control valve (ZCV) is a valve combines butterfly valve, water flow switch, pressure gauge and test & drain valve. ZCV has two functions; the first function is to indicate that there is a flow induced to the line serving a group of sprinklers in a specific zone in the case of fire, and the second function is to separate that zone in case of maintenance.