Divided by power:

Automatic valve: a valve that operates by relying on the force of the medium itself. Such as check valves, pressure reducing valves, drain valves, safety valves, etc.

Drive valve: a valve that is operated by external forces such as manpower, electricity, fluid power, and pneumatic power. Such as globe valves, throttle valves, gate valves, disc valves, ball valves, plug valves, etc.

Classified by purpose:

Disconnect valve: Cut off or connect the medium in the pipeline. Such as globe valves, gate valves, ball valves, plug valves, etc.

Regulating valve: regulates the pressure or flow rate of the medium. Such as pressure reducing valves and regulating valves.

Check valve: prevents medium backflow. Like a check valve.

Distribution valve: Changes the flow direction of the medium and plays a distribution role. Such as three-way cocks, three-way globe valves, etc.

Safety valve: When the pressure exceeds the limit value, excess medium is discharged to ensure equipment safety. Such as safety valves and accident valves.

Gas blocking and drainage valve: retain gas and discharge condensate, such as a drain valve.

Classified by manipulation method:

Manual valve: a valve that is manually operated using handwheels, handles, levers, sprockets, gears, worm gears, etc.

Electric valve: a valve operated by electricity.

Pneumatic valve: a valve operated by compressed air.

Hydraulic valve: a valve operated by transmitting external forces through liquids such as water and oil.

Classified by medium temperature:

Ordinary valves: valves between -40 to 450 ℃ (medium temperature).

High temperature valve: valve with medium temperature ranging from 450 to 600 ℃.

Heat resistant valve: a valve with a medium temperature above 600 ℃.

Low temperature valve: a valve with a medium temperature of -40 to -70 ℃.

Cryogenic valves: valves with medium temperatures ranging from -70 to -196 ℃.

Ultra low temperature valve: valves below -196 ℃ (medium temperature).

Classified by nominal diameter:

Small caliber: valves with a nominal diameter less than 40 millimeters.

Medium diameter: valves with a nominal diameter of 50 to 300 millimeters.

Large caliber: valves with a nominal diameter of 350 to 1200 millimeters.

Extra large diameter: valves with a nominal diameter greater than 1400 millimeters.

The above classifications are not absolute and can be classified from other perspectives. As long as you master these basic classifications, it is still very beneficial to understand the wide variety of valves.