Anesthesia apparatus having negative pressure relief means

Claim 1

In an anesthesia apparatus having an anesthetic gas conduit line with an inhalation end from which a patient receives an anesthetic gas mixture and an exhalation end into which the patient exhales carbon dioxide and any unabsorbed anesthetic gas, said gas conduit line further having a rebreathing bag, a carbon dioxide absorbing cannister, check valves to prevent patient''s intake of exhaled gases and to maintain the flow of anesthetic gas mixture towards the patient, a vaporizer chamber for the anesthetic, an anesthetic gas inlet and a relief valve for discharging preset gas pressure overloads out of the conduit line, the improvement which includes a gas diverting body member mounting a negative pressure relief valve, said gas diverting body member having a passageway communicating with the conduit line, an elongated tubular member mounted at one end to said gas diverting body member and mounted at the other end to a vacuum source to provide communication between said passageway and vacuum source, and said negative pressure relief valve having a chamber communicating with said passageway and means operable to communicate the chamber with atmospheric pressure upon development of negative pressures in the gas conduit line to thereby protect the patient against occurance of negative gas pressures and operable to close said chamber when said negative pressure condition is relieved.