A rotary valve is a type of valve in which the rotation of a passage or passages in a transverse plug regulates the flow of liquid or gas through the attached pipes.
The common stopcock is the simplest form of rotary valve.
Figure : airflow of rotary valve in two positions
Rotary valves have been applied in numerous applications, including:
- Changing the pitch of brass instruments.
- Controlling the steam and exhaust ports of steam engines, most notably in the Corliss steam engine.
- Periodically reversing the flow of air and fuel across the open hearth furnace.
- Loading sample on chromatography columns.
- Certain types of two-stroke engines.
- Most hydraulic automotive power steering control valves.
Uses
In industry, a rotary valve is used to regulate the flow of a product, usually to reduce the flow rate to a level more suitable to the process being undertaken. Typical applications are for feeding a weighed hopper or for feeding a mill that can be clogged by the product.
As part of the material exchange process, the valve is often used as a measuring or metering device.
A rotary valve in the pharmaceutical, chemical and food industry is used to dose and feed solid bulk products within the processes.
Airlock type rotary valve is often used to enter or extract material from two chambers with different pressure level.