Cannula gas flow meter

摘要

A meter for visual determination of proper oxygen or gas flow to a facemask or cannula from a pressurized gas supply. The device features a body with a central cavity extending axially therein adapted for translation of a piston biased toward an incoming gas stream from the pressurized supply. A cup-shaped endwall of the piston increases the area on which the incoming air stream acts. The incoming air stream is focused to impact a center portion of the endwall at a higher rate of speed using a narrowing incoming conduit resulting in increased force and translation of the piston even under the low pressures in which cannulas operate. The piston translates to a point where it may be viewed alone or adjacent to indica to ascertain proper oxygen flow to the user, by a caretaker from a distance.