Check valves, also known as round-trip valves or check valves, have a relatively simple and direct working principle. Its core function is to ensure that fluids (such as gases and liquids) can only flow in one direction and prevent them from flowing in the opposite direction. The following is the main working principle of the check valve:
Opening and closing of disc (or spool) :
When fluid flows through the inlet end of the check valve, the pressure of the fluid pushes the disc (or spool) away from its seat, allowing fluid to flow through the valve to the outlet end.
When the fluid pressure is greater at the outlet end than at the inlet end, or when the fluid tries to reverse flow, the disc (or spool) is tightly pressed against the seat by the reverse pressure or its own gravity, thus preventing the reverse flow of the fluid.
Spring assist:
In some check valve designs, springs are used to assist in disc closing. When the fluid pressure is reduced or disappeared, the spring's elasticity helps the disc return to the closed position quickly and reliably, preventing fluid backflow.
The use of the spring can also improve the sealing performance of the check valve under reverse pressure.
Fluid characteristics and check valve design:
The design of the check valve will vary depending on the type of fluid being handled (e.g. gas, liquid, corrosive fluid, etc.). For example, check valves that handle corrosive fluids may require the use of special materials to prevent corrosion.
Fluid pressure, temperature, and flow characteristics also affect the choice and design of check valves.
Application and Importance:
Check valves are widely used in a variety of industrial systems, such as hydraulic systems, pneumatic systems, chemical processes and water supply systems.
They are essential to prevent fluid backflow, protect system components from damage, and maintain stable system operation.