SPEAKING VALVES AND TRACHEOSTOMY TUBE ASSEMBLIES

摘要

A tracheostomy tube speaking valve (2) without any moving parts is formed with a Tesla valvular conduit of the kind having a flow passage (23) with a series of loops (26) and (27) the opposite ends of which are inclined towards the patient end (22) of the passage. This allows air to flow through the valve (2) preferentially from the machine end (21) to the patient end (22) to enable the patient to inhale but restricts flow in the opposite direction so that the major part of air exhaled by the patient is diverted to flow to the vocal folds. The length of the speaking valve (2) is contained entirely within the bore (18) of the tracheostomy tube (1).