1. In order to prevent the medium from flowing against current, check valves shall be installed on equipment, devices and pipelines;

2. Check valve is generally suitable for cleaning medium, and is not suitable for medium with solid particles and high viscosity;

3. Generally, horizontal lifting check valve shall be used for horizontal pipes with nominal diameter of 50mm;

4. The straight lift check valve can only be installed in horizontal pipe;

5. For the water pump inlet pipeline, the bottom valve should be selected. The bottom valve is generally only installed on the vertical pipe at the pump inlet, and the medium flows from the bottom to the bottom;

6. The lift type is better than the swing type, and the fluid resistance is large. The horizontal type should be installed on the horizontal pipe and the vertical one is installed on the vertical pipe;