Check valve is also called one-way valve, check valve and back pressure valve. Such valves are automatically opened and closed by the force generated by the flow of the mediator itself, which is an automatic valve. The function of the check valve is to prevent the backflow of the medium, prevent the reversing of the pump and its driving motor and the discharge of the medium in the container. The check valve is suitable for pipes of various media according to the different materials of the housing and the inner parts. Check valves can be divided into the following types according to their different structures.
1. closed check valve closed check valve
The swing check valve has a single valve check valve and a valve "valve" with multiple multiple valve check valves; it also has a split diameter swing check valve and a full diameter swing check valve. The structure of the single valve swing check valve is generally used in nominal size DN50~DN500; the multi disc swing check valve three 0 is generally used for nominal size DN600. The structure of the reduced diameter swing check valve is shown in figure 2-79. The structure of the full diameter swing check valve is shown in Figure 2-80.
2. lift check valve
The lift check valve is a check valve moving parallel to the axis of the seat hole. This check valve can only be installed on the horizontal line. The lift check valve, which is specially designed for the bottom of the pump suction pipe, is also called the bottom valve. Its function is to prevent the backflow of the medium when the pump is stopped, and to maintain the water column needed for pumping.
