GB703646A - Improvements in high-altitude oxygen breathing apparatus - Google Patents

Abstract

703,646. High altitude. respiratory appliances. BENDIX AVIATION CORPORATION. May 8, 1951 [May 12, 1950], No. 10834/51. Class 81(2) In an oxygen demand regulator in which a reducing valve controls the inlet and a demand valve passes oxygen from the reducing valve through an injector to the outlet, the movement of the reducing valve towards its open position is assisted by a pressure supplied from the inlet side of the injector. The path, through the regulator, followed by the oxygen from inlet 14, Fig. 2, leads past a stop valve 30 and filter 38 to the reducing valve 48, which is biased to the closed position by a spring 54 and to the open position by a spring 58, adjustable by screw 60, cooperating with an aneroid bellows 56. Oxygen thus flows through the valve into chamber 52 until the pressure therein collapses the bellows 56 sufficiently to close the valve 48. From chamber 52 the oxygen passes to a further chamber 62, Fig 3, normally closed by a demand valve 74. When this is opened, by the user's inspiration, oxygen flows through a nozzle 96, thereby entraining ambient air through ports 100 and passing on to the outlet 166. If the demand exceeds a predetermined minimum the pressure in the space 82 lifts the nozzle body 84 off its seating 94, against a spring 88, and the excess oxygen flows through ports 102, space 106 and ports 108 tothe outlet 16. The pressure in the space 82 is communicated through ducts 114 and 120, Fig. 2, to the interior of the bellows 56, thereby increasing the opening of the reducing valve 48 to increase the flow of oxygen to meet the greater demand. Specification 690,382 is referred to.