A check valve consists of three parts: the valve body, the valve core, and the spring. During operation, the medium enters the valve body through the inlet. When the medium flows in the specified direction, the valve disc opens under the force of the medium, allowing normal flow. In reverse flow, the valve disc closes under its own weight and the opposing force of the medium, preventing backflow. Due to this principle, a check valve will have some impact on the water pressure and flow rate; however, if a properly sized check valve is used, the impact is negligible.
The structure of a check valve is relatively simple, mainly consisting of the valve body, valve core, and spring. The inlet and outlet on both sides are connected to the pipeline via connectors. A check valve only allows the medium to flow in one direction, and is completely closed in the opposite direction. When air pressure is applied to the left side, the air pressure acting on the valve core overcomes the spring force and friction, opening the valve core and connecting the inlet and outlet of the medium. The flow of medium from left to right is called forward flow. To ensure stable flow from the inlet to the outlet, a certain pressure difference should be maintained between the inlet and outlet to keep the check valve in the open position.
The check valve prevents backflow of the medium entering it. However, while doing so, the check valve also has some impact on the water pressure of the internal medium. Because the check valve prevents backflow through its valve disc, it will affect the flow rate to some extent. The specific impact depends on the inner diameter of the check valve. If the rated flow rate of the selected check valve matches the required flow rate, the impact is negligible. However, if an unsuitable check valve is selected, it may have a significant impact on the flow rate.
The pressure difference generated by the flow through the check valve is related to the opening pressure of the check valve. Using a properly sized check valve has a relatively small impact on the water pressure unless the system pressure is too low. If it is found that the check valve is reducing the water pressure, the following two methods can be used to solve the problem: one is to increase the pressure in front of the check valve. This method is relatively simple, but not economical. The more economical approach is to change the structure of the check valve, that is, to select a check valve with a smaller pressure drop.