GB742520A - Improvements in or relating to safety devices in oxygen respirators - Google Patents

Abstract

742,520. Respiratory appliances. AUERGES., AKT.-GES. Dec. 30, 1953 [Dec. 30, 1952], No. 36178/53. Class 81(2). A safety device in a protective respirator provided with a lung-controlled oxygen supply valve comprises a change-over valve device interposed between the lung-controlled oxygen supply valve and a pressure reducing valve of an oxygen supply reservoir, the change-over device being arranged when actuated by means outside the protective housing of the respirator, to cut off the lung-controlled valve and to open a by-pass conduit provided with a throttle aperture to ensure uniform-rate oxygen delivery. The change-over device 12 is interposed between the pressure reducing valve 10 of an oxygen canister 3 and the lung-controlled oxygen supply valve 15 which is connected with the respiration circuit by a pipe 17. A conduit 16 connecting the changeover valve device 12 with the pipe 17 by-passes the lung-controlled valve 15. The change-over valve device 12 comprises a housing 20 in a central bore 23 of which oxygen passes through a conduit 11. In normal operation of the apparatus oxygen flows through a first nozzle 24 to a conduit 14 and the lung operated valve 15, a second nozzle 26 being closed by a spring-pressed valve member 28. In the event of failure of the lungcontrolled valve 15 the valve member 28 is moved in the bore 23 to close the first nozzle 24 and open the second nozzle 26 by operating a thrust pin 32 by means of a handle 13 on the outside of the apparatus. Oxygen then flows into the respiration circuit of the apparatus through the by-pass conduit 16. A throttle aperture 37 or the annular gap between the second nozzle 26 and the thrust pin 32 are so dimensioned that the required uniform-rate oxygen delivery is provided. A by-pass valve 8 is connected to the respiration circuit by pipes 8a, 17.