(2) Check type: such as check valve, check valve is also called one-way valve or check valve. Inversion, and leakage of container media. The bottom valve of the water pump suction valve also belongs to the check valve category.

(3) Safety category: such as safety valves, explosion-proof valves, emergency valves, etc. The function of the safety valve is to prevent the medium pressure in the pipeline or device from exceeding the specified value, so as to achieve the purpose of safety protection.

(4) Regulating type: such as regulating valve, throttle valve and pressure reducing valve, whose function is to adjust the pressure, flow and other parameters of the medium.

(5) Diversion: such as distribution valves, three-way valves, and steam traps. Its function is to distribute, separate or mix the medium in the pipeline.

(6) Special purpose categories: such as pigging valves, vent valves, blowdown valves, exhaust valves, filters, etc. The exhaust valve is an indispensable auxiliary component in the pipeline system, and is widely used in boilers, air conditioners, oil and gas, water supply and drainage pipelines. It is often installed at commanding heights or elbows to remove excess gas in the pipeline, improve the efficiency of pipeline use and reduce energy consumption.