GB793452A - Improvements in breathing apparatus for use in aircraft - Google Patents

Abstract

793,452. Respiratory apparatus. KIDDE CO., Ltd., W. Feb. 16, 1956 [Feb. 16, 1955], No. 4584/55. Class 81 (2). [Also in Group XXIX] Multiple outlet breathing apparatus comprises a master regulator 33 which is connected to a high-pressure oxygen supply 31 and supplies oxygen to a multiple outlet distribution manifold 34 at an intermediate pressure of the order of 100 p.s.i., each outlet 35 of the distribution manifold 34 being connected to an individual face mask 38 and a slave regulator in the form of a reducing valve 37, the outlet pressures of the slave regulators being controlled by change in outlet pressure of the master regulator 33. The face masks 38 are connected to selfsealing outlets 35 and receive the oxygen through the reducing valves 37. The master regulator, Fig. 6, is provided with a cone-shaped valve member 61 controlled by a diaphragm 62. Sealed bellows 63 carry a thrust-member 64 which, as atmospheric pressure is reduced due to increased altitude, augments a control spring 65 in bearing on the diaphragm 62, the arrangement being such that the outlet pressure increases as atmospheric pressure decreases. The bellows 63 may be arranged to reduce the loading of the spring 65 as atmospheric pressure decreases. One form of reducing valve, Fig. 1, which gives a decreased mask pressure as the pressure in the manifold increases includes a valve head 5A which is on the inlet side of the valve and which is controlled by a diaphragm 2 exposed to the outlet pressure. In another form of reducing valve, Fig. 2, which gives an increased mask pressure with an increase of manifold pressure, the valve seat 21 is mounted on a diaphragm 22 and as manifold pressure increases moves away from the valve head 20 which is controlled by a diaphragm 16 on the outlet side of the valve. A venturi 24 which is closed by the valve seat 21 as manifold pressure increases allows outside air to be drawn into the outlet side of the valve through apertures 25 at lower altitudes. A release valve (see Group XXIX) which automatically opens when atmospheric pressure falls to a predetermined value, may be provided between the oxygen supply and the regulator 33. Such a release valve has an over-riding manual control.