GB763804A - Improvements in or relating to breathing apparatus - Google Patents

Abstract

763,804. Respiratory apparatus. SVENSKA AKTIEBOLAGET GASACCUMULATOR. Jan. 25, 1955 [Jan. 26, 1954], No. 2203/55. Class 81(2) Breathing apparatus comprises a valve arrangement for controlling supply of gas such as oxygen including a valve chamber connected to a breathing mask or the like through an exhalation passage and having an exhalation outlet valve, and valve means for controlling the supply of oxygen to the mask through an inhalation passage separate from the exhalation passage, the valve means being responsive to pressure in the valve chamber whereby the valve means is closed during exhalation, when pressure within the chamber exceeds atmospheric pressure, and opens when pressure in the chamber falls on inhalation. A diaphragm 2 forms one side of a valve chamber 1 and is provided with an exhalation valve formed by a flexible disc 4 which opens or closes holes 3 in the diaphragm 2. The valve chamber 1 is connected to a mask 21 having a window 22 by an exhalation passage 12. An inhalation passage 11 is provided inside the exhalation passage 12 and connects a passage 10 through which oxygen is supplied to the mask 21. A spring-closed valve 9 controls the oxygen supply through the passage 10 and is operable by the diaphragm 2 through a pivoted lever 7 so that it opens when pressure in the chamber 1 falls during inhalation. The inhalation passage 11 may be connected with a tight-fitting breathing mask within a face mask. In an alternative construction the exhalation valve is provided in the wall of the chamber opposite the diaphragm and is connected to the diaphragm so that when the pressure in the chamber rises the valve moves away from an exhalation aperture.