Rotary valve

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. Rotary valves have been applied in numerous applications, including:

In the context of brass instruments, rotary valves are found on horns, trumpets, trombones, flugelhorns, and tubas. Many European trumpet players tend to favor rotary valves.

Trombone F-attachment valves are usually rotary, with several variations on the basic design also in use, such as the Thayer axial-flow valve and Hagmann valve.

Joseph Riedl is credited with the first use of rotary valves on brass instruments in 1832.

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.

The rotary valve combustion engine possesses several significant advantages over the conventional assemblies, including significantly higher compression ratios and rpm, meaning more power, a much more compact and light-weight cylinder head, and reduced complexity, meaning higher reliability and lower cost. As inlet and exhaust are usually combined special attention should be given to valve cooling to avoid engine knocking.

Rotary valves have been used in several different engine designs. In Britain, the National Engine Company Ltd advertised its rotary valve engine for use in early aircraft, at a time when poppet valves were prone to failure by sticking or burning.

From the 1930s, Frank Aspin developed a design with a rotary valve that rotated on the same axis as the cylinder bore, but with limited success.

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