What is a check valve?

Time:2025.03.06 Posted By: Peter

As an indispensable component in fluid control systems, check valve play a key role in domestic water supply, industrial production and public facilities.

 

Definition of Check Valve

A check valve, also known as a one-way valve or non-return valve, is an automatic valve that is mainly used to control the one-way flow of fluid and prevent the medium from flowing back. Its core function is to allow the fluid to pass freely in one direction and automatically close when the fluid tries to flow in the opposite direction, thereby preventing the occurrence of backflow.

 

Working principle of check valve

The working principle of the check valve mainly depends on the fluid pressure: when the fluid flows in from the inlet end, the valve disc opens under the action of pressure to allow the fluid to pass; when the fluid tries to flow in the opposite direction, the valve disc quickly closes under the action of gravity or spring force to prevent backflow.

 

The difference between check valve and stop valve

characteristic

Check valve

Stop valve

Function

Prevent fluid backflow and ensure one-way flow

 Completely open or close fluid flow

How to operate

Automatic operation, no human intervention required

 Manual or actuator operation

structure

Simple structure,no external driving parts

 Complex structure, with valve stem and hand wheel and other parts

Sealing performance

Better, but may leak slightly at low pressure

 Zero leakage can be achieved

Classification of check valves

Rising Threaded End Check Valve

The vertical check valve opens due to the medium pressure at the inlet end of the pipeline, overcoming the resistance of the valve spring. When the medium pressure at the inlet end is lower than that at the outlet end, the spring pushes the valve core to the valve seat to close the valve to prevent the medium from flowing back.

Wafer Check Valve

The wafer-type check valve has two semicircular discs. The fluid pressure pushes the disc to open. When reverse flow occurs, the disc closes. It is suitable for places with limited space.

Swing Check Valve

The disc of the swing check valve rotates around the axis and is suitable for large-diameter pipelines. It has a simple structure and good sealing performance.

Application scenarios of check valves

1. Water supply system: In household and building water supply systems, check valves prevent water from flowing back when the pump stops running, protecting the pump equipment.
2. Industrial pipelines: In the chemical, petroleum, and electric power industries, check valves are used to prevent medium backflow and ensure the stability of the process flow.
3. HVAC system: Check valves prevent hot and cold water from mixing and maintain the thermal efficiency of the system.
4. Sewage treatment: In sewage treatment systems, check valves prevent sewage from flowing back and avoid environmental pollution.
5. Firefighting system: Check valves play a key role in firefighting pipelines to ensure that firefighting water is available at any time.

 

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