Introduction to the principle of check valve

Check valve, also known as check valve, check valve, its working principle is mainly based on the automatic opening and closing of the valve disc to control the one-way flow of the medium and prevent backflow. The following is a detailed introduction to the working principle of the check valve:

First, the basic working principle

The working principle of the check valve can be summarized as follows: when the medium (such as liquid, gas, etc.) flows in a predetermined direction, the valve disc is automatically opened by the pressure of the medium, allowing the medium to pass through; When the medium tries to reverse flow, the valve disc automatically closes under the action of the medium pressure and its own gravity, preventing the medium from backflowing.

Second, the specific working principle

According to the structural form of the check valve, its working principle is slightly different, but the basic principle is similar. The following uses swing check valves and lift check valves as examples:

1. Swing check valve

Structural features: The disc of swing check valve is connected with the valve body through the hinge mechanism, and can be freely rotated. The disc is usually disc-shaped and rotates around a pin in the center of the seat.

Working principle: When the medium is flowing forward, the valve disc is subjected to the pressure of the medium, and rotates around the pin shaft to allow the medium to pass; When the medium flows backward, the valve disc is subjected to the double action of the medium pressure and its own gravity, and rotates around the pin shaft to prevent the medium from flowing backward.

2. Lift check valve

Structure features: The flap of the lift check valve moves up and down along the axis. The disc is usually located on the seat sealing surface of the valve body and can be lifted and lowered freely.

Working principle: When the medium is flowing forward, the valve disc is lifted by the pressure of the medium, and the channel is opened to allow the medium to pass; When the medium flows backward, the valve disc is reduced by the double action of the medium pressure and its own gravity, and the channel is closed to prevent the medium from flowing backward.

Third, work characteristics

Check valves have the following operating characteristics:

1. Automaticness: The check valve is an automatic valve that does not require external control or intervention to achieve one-way flow of the medium and prevent backflow.

2. Sealing: The check valve has a good sealing performance between the disc and the seat to ensure that the medium can be effectively prevented when the reverse flow.

3. Reliability: The check valve has simple structure and reliable operation, and can maintain stable working performance under various working conditions.

Fourth, application field

Check valves are widely used in a variety of fluid systems, such as water supply and drainage systems, HVAC systems, industrial production processes, etc., to prevent media backflow and protect equipment and systems from damage.

To sum up, the check valve controls the one-way flow of the medium and prevents backflow through the automatic opening and closing of the valve disc. Its working principle is simple and reliable, and it plays an important role in various fluid systems.