Fluidization patient support control system

Claim 1

A fluidization patient support system without excess air flow that causes "pinging" around the patient comprising: an elongated fluidization tank having an open top; a porous, flexible filter sheet secured over said open top; fluidizable granular material below said sheet to support a patient thereon when fluidized; a diffuser beneath said granular material to diffuse pressurized fluid flowing to said granular material and to support said granular material when not fluidized; a plenum beneath said diffuser to receive air to be diffused; a compressor-blower having an air inlet to the ambient atmosphere and having an outlet; conduit means from said outlet to said plenum for conducting compressed air to said plenum and thence to said diffuser; variable control valve means in said conduit means for controlling the flow of compressed air to said plenum; a diversionary discharge outlet from said conduit means at said control valve means to divert air from flow to said plenum, said variable control valve means being shiftable over a variety of positions enabling control of the ratio of air flow to said plenum with respect to air flow to said diversionary discharge outlet; and actuator means for said control valve means, allowing regulation of said ratio of air flow to said plenum and said diversionary discharge outlet and thereby flow of air through said porous sheet to be regulated for providing adequate patient support while preventing excessive flow through said porous sheet causing unpleasant pinging sensations for the patient.