Portable drag compressor powered mechanical ventilator

A flow transducer for measuring the flow rate of a fluid, said transducer comprising:

• a housing defining a first fluid flow path therethrough;
• a deflectable flapper disposed transversely within said fluid flow path such that said flapper will deflect in the direction of fluid flow, thereby creating a fluid flow restriction permitting some fluid to flow pass said flapper and through said flow path;
• a first pressure port located upstream of said flapper for measuring the pressure of fluid within said flow path, upstream of said flapper;
• a second pressure port downstream of said flapper for measuring the pressure of fluid flowing through said flow path, downstream of said flapper;
• means associated with said first pressure port for determining the pressure of fluid flowing upstream of said flapper;
• means associated with said second pressure port for determining the pressure of fluid flowing downstream of said flapper;
• means for determining the difference between the pressure of fluid flowing upstream of said flapper and the pressure of fluid flowing downstream of said flapper;
• means for computing the flow rate of fluid through said flow path, based on the measured difference in pressures upstream and downstream of said flapper;
• said deflectable flapper comprising a rigid frame having a central aperture formed therein;
• a flat sheet of pliable material mounted within said frame member and forming a flapper disposed transversely within said central aperture of said frame and deflectable in at least one direction to permit fluid to flow pass said flapper and through said central aperture;
• said frame being mounted transversely within said flow path such that fluid flowing in a first direction through said flow path will strike said flapper thereby causing said flapper to deflect in the direction of flow such that the flowing fluid may pass through said central aperture;
• and
• a cushioning member associated with said frame to distribute the force exerted by said frame on said flat sheet of pliable material, thereby distributing any stresses created within said flat sheet of pliable material.