Valves can be categorized into the following basic types:
- Ball valve, for on/off control without pressure drop, and ideal for quick shut-off, since a 90° turn offers complete shut-off angle, compared to multiple turns required on most manual valves.
- Butterfly valve, for flow regulation in large pipe diameters.
- Ceramic Disc valve, used mainly in high duty cycle applications or on abrasive fluids. Ceramic disc can also provide Class IV seat leakage
- Clapper valve, Used in appliances like the Siamese fire appliance to allow only 1 hose to connected instead of two (the clapper valve blocks the other side from leaking out.
- Check valve or non-return valve, allows the fluid to pass in one direction only.
- Choke valve, a valve that raises or lowers a solid cylinder which is placed around or inside another cylinder which has holes or slots. Used for high pressure drops found in oil and gas wellheads.
- Diaphragm valve, which controls flow by a movement of a diaphragm. Upstream pressure, downstream pressure, or an external source (e.g., pneumatic, hydraulic, etc.) can be used to change the position of the diaphragm.
- Gate valve, mainly for on/off control, with low pressure drop.
- Globe valve, good for regulating flow.
- Knife valve, similar to a gate valve, but usually more compact. Often used for slurries or powders on/off control.
- Needle valve for accurate flow control.
- Pinch valve, for slurry flow regulation and control.
- Piston valve, for regulating fluids that carry solids in suspension.
- Plug valve, slim valve for on/off control but with some pressure drop.
- Poppet valve, commonly used in piston engines to regulate the fuel mixture intake and exhaust
- Spool valve, for hydraulic control
- Thermal expansion valve, used in refrigeration and air conditioning systems.
- Pressure Reducing Valve
- Sampling valves
- Safety valve