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A Check valve often called as Non Return Check valve or One-way valve is a vale that normally only allows fluid to flow forward one direction. Check valves have two ports, one for entering and the other one for leaving.
FLOWORK® mainly produces Check valves according to the standard of API 6D. (API 6D Check valves)
According to different design standards, FLOWORK® provides you DIN Check valves as well.
The body of Check valves may be made of metals. Such as: Forged Steel Check valves，Stainless Steel Check valves, Alloy Check valves, Bronze Check valves, Cast Steel Check valves and Carbon Steel Check valves,ect. FLOWORK® mainly produces Forged Steel Check valves according to the standard of API 602. and Stainless Steel Check valves according to the standard of API 603,We call them API 602 Forged Steel Check valves and API 603 Stainless Steel Check valves.The body can also be made of Non-Metal materials. For example, Ceramic Check valves, which have good performance of abrasion and hardness under high pressure and high temperature.Some other Globe valves are made of special materials, such as HastelloyCheck valves,Special SteelCheck valvesand Special AlloyCheck valves.Transmitting and processing of media that are heavily corrosive, Duplex Stainless Steel Check valves or Super Stainless Steel Check valves are usually selected to mitigate the problems for they can work well in the area with corrosive surroundings.
Check valves are normally operated automatically without control of human beings or external force, thus needing no hand levers or stems. The only one exception is the Stop Check valves in which fluid can be stopped flowing suddenly under the control of external forces when necessary.
According to its different constructions,Check valves can be divided into 3 types, they are Lift Check valves, Swing Check valves and Butterfly Type Check valves.When the fluid flows and stops continuously，Lift Check valvescan be selected. However,Lift Check valvescan only be installed in a horizontal pipe.
The most common Check valves are Swing Check valves. When the valves are fully opened, the fluid receives only small resistance.The Butterfly Type Check valves also referred to as Disc Check valves have simple structure and good sealing, which can only be installed in horizontal pipes.
There are other types of Check valves. A Ball Check valve is a type of Check valve with a ball without a hole for a disc. A Duckbill valve shaped like the beak of a duckis a type of Check valve. Usually made from rubber , the Duckbill valvesareoften used as backflow prevention devices in some applications, for example, medicine.
According to different types of connections, there are Screwed Check valves, Flanged Check valves, Butt Weld Check valves, Socket Weld Check valves and Wafer Check Valves. Bronze Wafer Check Valves can work well in highly corrosive conditions. Check valves normally will make great noise when they are working, except for the Dual Plate Wafer Check Valves. With the flow of the fluid, the two-spring-loaded plates hinged on a central hinge pin swing like a butterfly’s wings. When the flow decreases, the plates close by the action of torsion spring before flow reversal takes place. This design prevents Water Hammer and Slam at the same time, thus making the Dual Plate Wafer Check Valves the most efficient and versatile design. That’s why they are also referred to as Silent Check valves.
FLOWORK provides different valves under different operating conditions，especially different temperatures. High Temperature Check valves, Low Temperature Check valves/ Cryogenic Check valves and Jacket Check valves are adopted to work under different operating temperatures. Jacket Check valves help to prevent the line fluid’s temperature loss. For high temperature conditions, we can also select High Nickel Alloy Check valves. Under high pressure, sedelon’s High Pressure Check valves are good choices.
Pressure Seal Check Valves can adjust the pressure of sealing ring automatically to fit with the different inner pressures in the pipeline. This type of Check valves is usually used in high temperature and high pressure operating conditions.
A Double Check valve commonly used in applications which have great demands of preventing pollution from backflow, like, keeping potentially contaminated water from flowing back to watersupply lines.
