(1) Cut-off valve : The cut-off valve is also called a closed-circuit valve, and its function is to connect or cut off the medium in the pipeline. Cut-off valves include gate valves, globe valves, plug valves, ball valves, butterfly valves and diaphragms.

(2) Check valve: Check valve also known as unidirectional valve or non-return valve, its role is to prevent the medium flow back in the pipeline. The bottom valve of the water pump suction switch also belongs to the check valve category.

(3) The role of safety valves is to prevent the pressure of the medium in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.

(4) Regulating valve: Regulating valves include control valve, throttle valve and pressure reducing valve, whose function is to regulate the pressure and flow parameters of medium.

(5) Shunt valve: Shunt valves include various distribution valves and traps, whose function is to distribute, separate or mix the medium in the pipeline.

(6) Exhaust valve: Exhaust valve is an indispensable auxiliary component in the pipeline system, which is widely used in boilers, air conditioning, oil and gas, water supply and drainage pipelines. It is often installed at the commanding point or elbow to remove the excess gas in the pipeline, improve the use efficiency of the pipeline and reduce the energy consumption.