Tubular-pneumatic action

"Tubular-pneumatic action" refers to an apparatus used in many pipe organs built during the late 19th and early 20th centuries.

In any organ, each pipe has a valve located at its foot which responds to the organist's commands from the console's keyboard, pedalboard and stop controls.

In 1845, Prosper-Antoine Moitessier, an organ-builder of Montpellier, France, patented the tubular-pneumatic system, [1] which allowed the console to be at a much greater distance from the organ pipes.

Cavaillé-Coll, Henry Willis and Edwin Horsell Pulbrook were pioneers in perfecting and introducing the pneumatic action.

Both use three major components for each key and stop: a valve (within the console), a pneumatic motor, commonly called a 'pneumatic' (within the windchest), and a lead tube that connects them.

Depressing a key increases the pressure in the tube, inflating the pneumatic, which opens the pipe's valve.

Depressing a key lets this pressure exhaust, which collapses the pneumatic and opens the pipe's valve.