Heat sterilizable patient ventilator

Claim 1

In a heat-sterilizable patient ventilator of the type including a ported center-body having means defining a circumscribing annular shoulder, a shell mounted on said shoulder for defining in juxtaposition with the center-body an hermetically sealed reservoir for confining gas consisting essentially of a bacteria-free mixture of ambient atmospheric gas and pure oxygen, and means for discharging said mixture from said reservoir including a first tubular gas conduit extended from said reservoir to a discharge fitting, the improvement comprising: means for delivering bacteria-free gas to said reservoir including, A. a second tubular gas conduit of relatively constant diameter extending from said reservoir having means defining at one end thereof a gas discharge port communicating with said reservoir and means defining at the other end thereof an ambient gas intake port remotely related to said gas discharge port; B. filter means connected to the second tubular gas conduit at the said other end thereof for substantially sealing said ambient gas intake port against entry of microorganisms including: 1. a filter housing, 2. a dust filtration unit seated in said housing formed of Scott filter foam, 3. a microbial filtration unit seated in said housing in juxtaposition with said dust filter unit including a plurality of screen-supported bacterial retentive pads formed of FM-004 fiberglass filter material, and 4. a media migration filtration unit seated in said housing in juxtaposition with said microbial filtration unit formed of Scott filter foam; and C. means including a gas jet coaxially related to said second tubular gas conduit for discharging into the second conduit a stream of gas consisting essentially of pure oxygen.