What is the working principle of spring check valve

Check valves are widely used and there are many types. The following are commonly used check valves for water supply and heat:

1. Spring type: The liquid moves from bottom to top, relying on the pressure to lift the valve disc controlled by the spring. After the pressure disappears, the spring force presses the valve disc to seal the backflow of the liquid. Often used for small diameter check valves.

2. Gravity type: Similar to the spring type, it is closed by the self-gravity of the valve disc to prevent backflow.

3. Swing type: The liquid flows straight through the valve body, and the rotary valve flap on one side is opened by the pressure. After the pressure is lost, the valve flap returns to its position by its own weight, and the reverse liquid pressure closes the valve flap.

4. Plastic diaphragm type: The shell and diaphragm are all plastic, and the diaphragm is made of silicone resin, fluorine resin, etc.

Other one-way valves (check valves), such as sewage check valves, civil air defense explosion-proof valves and liquid check valves, are basically similar in decoration.

A one-way valve is a directional control valve in which the airflow can only move in one direction and cannot move in the opposite direction. Its working principle is the same as that of hydraulic check valve. Compressed air enters from the corpse port, overcomes the spring force and frictional force to open the valve port of the one-way valve, and the compressed air flows from P to A; when there is no compressed air at the P port, the spring force and the A port (cavity) residual air force act. down; the valve port is in a closed state, so that the air flow from A to P is blocked. The one-way valve is used in situations where the reverse flow of the airflow is not allowed. For example, when the air compressor is inflating the air tank, a one-way valve is set between the air compressor and the air tank. When the air compressor stops working, it can prevent the air tank from working. The compressed air is returned to the air compressor. One-way valves are also often combined with throttle valves and sequence valves to form one-way throttle valves and one-way sequence valves.