GB862367A - Improvements in or relating to lung-controlled breathing apparatus - Google Patents

Abstract

862,367. Respiratory appliances. DRAGER, O. H. July 1, 1957 [June 30, 1956], No. 20701/57. Class 81 (2). Lung-controlled breathing apparatus comprises first and second chambers 8, 9 separated by a wall 7 movable in response to increased pressure in the second chamber 9 on exhalation to open a pressure-reducing valve 5 in an inlet 1 for gas under pressure to the first chamber, the first chamber being connected to the respiratory organs of the user by an outlet 12 to which the second chamber is also connected by a further duct 14 having a valve 13 which permits exhaled gas to pass into the second chamber. Gas under high pressure enters a chamber 8, on one side of a diaphragm 7, through a bore 3 and a valve seat 4 on which bears a spring-loaded valve member 5. On inhalation through a pipe 12 connecting the user to the chamber 8, the diaphragm 7 moves inwardly of the chamber 8 and operates a lever to open the valve member 5. On exhalation through the pipe 12, gas opens a non-return valve 13 and flows into a second chamber 9 on the other side of the diaphragm 7. An exhalation valve 21, the closure pressure of which is such that a positive pressure is maintained in the chambers 8 and 9, permits gas to be exhausted to atmosphere. The exhalation valve 21 is connected through a spring 22 to an aneroid capsule 24 exposed to the atmosphere, so that with increase in altitude the closing pressure of the valve 21 is increased. Thus at increased altitudes the pressure in second chamber 9 rises and is transmitted through the diaphragm 7 to gas in the first chamber 8. A bleed aperture 15 in the non-return valve 13 allows the gas pressure on both sides of the diaphragm 7 to be equalized when the apparatus is not in use.