In this article, we will go through what is check valve, the parts of a check valve, the types of check valves, their function, and the application of a check valve. After reading this complete post your queries related to what is check valve is will be cleared. So let’s dive into detail about what is check valve.
What is check valve?
A check valve is a one-way valve that prevents the backflow in the pipeline. It is also known by several other names such as Non-return valve, Reflux valve, One-way valve, and Retention valve.
The primary purpose of this valve is to allow the flow in one direction and prevent backflow in the system. The check valve operates on the principle of differential pressure concept.
All types of check valves are self-operated valves i.e. they do not require any kind of mechanism or system to operate it. These kinds of features make it easier to operate, and effective & economic solutions for the system.
Amazing facts about the Check valve
- They are one of the essential components in the design of an efficient piping system.
- They are self-operated valves and do not require any supporting mechanism to operate like a lever, actuator, or gear.
- Check valves should be selected based on their size for their application & flow and not merely on pipe diameter.
- It is an essential valve in the design of an efficient pumping system.
- Often pressure surge or sudden wave is observed when a fluid is forced to stop suddenly or change direction and this causes water hammer in the line.
- The water hammer can be reduced significantly with the choice of a correct check valve.
- Some sort of leakage is usually observed in metal seated check valve while soft seat such as Viton, Nitrile, and Buna-N offers bubble-tight shutoff (zero leakage).
Different types of check valves
As per the various designated applications, different types of check valves are available. One can choose different types of check valves as per the design & application area. Let us see each one of the types of check valves.
- Ball Check Valve
- Disc Check valve or Wafer check valve
- Dual plate check valve
- Lift Check valve
- Non-slam check valve
- Nozzle Check valve
- Piston Check valve
- Swing Check valve
- Stop Check valve
- Tilting Disc Check valve
Ball check valve
In the Ball check valve, a loose ball is used inside the body as a stopper. The ball then moves up and down inside the ball check valve.
The seat of the ball check valve is machined in such a way that the ball fits perfectly and the ball chamber is conically shaped to stop the reverse flow.
It has simple flow efficiency and has maintenance-free design due to which it has been specifically used in submersible wastewater lift stations.
Sometimes the ball check valve makes noise during operation it may be due to pump capacity or water hammer issues.
Disc Check valve or wafer check valve
A Disc Check valve is also known as a wafer type of non-return valve. It consists of Disc, spring & main body. The opening & closing of the disc check valve is determined by the flowing direction of the fluid in the pipeline.
The pressure of the fluid opens the check valve thru spring compression but it does not allow the reverse flow as it closes the disc. They are called disc check valves as they tend to fit between any flanges of various standards and in any position, including vertical direction.
A disc check valve or wafer check valve is commonly used for handling water, steam, and oil.
Note: Disc check valve or wafer check valve is not suitable for those applications where heavy and pulsating fluid exists such as the compressor.
Dual plate check valve
A dual plate check valve is also known as a non-return valve or retainer less check valve. The dual plate check valve consists of two spring-loaded plates hinged on the center hinge pin.
It is an all-purpose non-return valve that is much stronger, lighter in weight, and compact in design as compared to a conventional swing check valve or lift check valve.
