Valves can be divided into two main categories.
1. Automatic valve—a valve that acts on the condition of the medium itself, such as check valves, pressure reducing valves, steam traps, etc.
2. Drive valves - valves that rely on manpower, electricity, hydraulics and pneumatics, such as manual shut-off valves, electric gate valves, etc.
We can also classify in the following ways.
1. According to the structural features, it is divided into gate type, as of the door type, and the swing type.
2. According to the use, it is divided into cutting, non-returning, and adjusting.
3. Classified by manipulation method:
Manual: Direct transmission with hand wheel or with handle; transmission through gear or turbine; long distance transmission through sprocket or universal joint.
Electric: It is driven by a motor through a reducer and an electromagnetic drive.
Hydraulic and pneumatic.
4. Classified by media pressure:
Vacuum valve: A valve with an absolute pressure below 0.1 MPa.
Low pressure valve: A valve with a pressure below 1.6 MPa.
Medium pressure valve: A valve with a pressure of 2.5 - 3.6 MPa.
High pressure valve: A valve with a pressure higher than 9.8 MPa.
5. According to the temperature of the medium: ordinary valves, high temperature valves and ultra-high temperature valves.
6. Classified by nominal diameter: small diameter valves, medium diameter valves, large diameter valves and extra large diameter valves.