A valve is a component that is used to control or shut off the flow of liquids or gases.
Table 1. Possible subdivision of valves| Task or function | Terminating body | Actuator | Housing shape | Valve seat | Number of valve seats |
|---|
| Shut-off valves | Disc valves | Solenoid valves | Globe valves | Straight seat valves | Single seat valves |
| Control valves | Plug valves | Float valves | Angle valves | Angle seat valves | Double seat valves |
| Throttle valves | Diaphragm valves | Motorised valves | 3-way valves | | |
| Safety valves | Needle valves | Thermostatic valves | | | |
| Overflow valves | Ball valves | Pneumatic valves | | | |
| Check valves | Piston valves | Hydraulic valves | | | |
