Brass instrument valves

Brass instrument valves are valves used to change the length of tubing of a brass instrument allowing the player to reach the notes of various harmonic series. Each valve pressed diverts the air stream through additional tubing, individually or in conjunction with other valves. This lengthens the vibrating air column thus lowering the fundamental tone and associated harmonic series produced by the instrument. Valves in brass instruments require regular maintenance and lubrication to ensure fast and reliable movement.

The first piston-valved musical instruments were developed just after the start of the 19th century. The Stölzel valve (invented by Heinrich Stölzel in 1814) was an early variety. The piston valve found in the majority of valved brass instruments was invented in 1838 and patented in 1839. They are sometimes called Périnet valves after their inventor, François Périnet. They work by diverting air obliquely through ports in the stock of the valve so that a loop of tubing is included in the air stream, lowering the pitch. The stock of the valve is cylindrical and moves up and down through a larger cylindrical casing.

The rotary valve works using a short circular plug housed in a larger cylindrical casing. Ports are cut along one plane through the stock and direct the airflow into the lengths of tubing when the stock is rotated 90 degrees. 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. Horns almost always have rotary valves, and many tubas have rotary valves. Joseph Riedlin is credited with the first use of rotary valves on brass instruments in 1832.

The Thayer axial flow valve is an alternative for the traditional rotary valve found on trombones with valve attachments. It was invented by Orla Ed Thayer (with assistance from Zig Kanstul) in 1976. It uses a conical plug, allowing a deflection of the airflow by only 25 degrees or less.

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