Mask for adminstering an anesthetic gas to a patient

Claim 1

A mask for administering gas to a patient comprising: (a) an inner cup-shaped wall having an inner surface and a peripheral edge, said inner wall being constructed and configured to fit over the nose or mouth of the patient and to engage the face of the patient along the peripheral edge thereof to form a gas chamber confronting the face of the patient, said inner wall being formed with a valve seat having at least one opening therein communicating with said gas chamber; (b) an outer wall detachably secured to said inner wall by a releasable securing means for facilitating the removal of said outer wall from said inner wall to enable said outer wall to be reused while discarding said inner wall, said outer wall being spaced from said inner wall to define an exhaust passage therebetween; (c) gas inlet means supported by said outer wall and including a conduit communicating with said gas chamber for introducing gas into said gas chamber to be administered to the patient, said conduit being detachably secured to said inner wall; (d) exhaust outlet means supported by said outer wall and communicating with said exhaust passage for the removal of exhaust gas from said exhaust passage; and (e) a flexible floating valve disc attached to said valve seat and arranged to form a sealing closure with said valve seat overlying said opening in said valve seat, said flexible floating valve disc being interposed between said valve seat and said outer wall, said floating valve disc forming a sealing closure with said valve seat over said opening in said valve seat in response to the patient inhaling to inhibit communication between said gas chamber and said exhaust passage, said floating valve disc being radially displaced from said opening in said valve seat for exhaust gas in said gas chamber to enter said exhaust passage in response to the patient exhaling.