GB482492A - Improvements in and relating to breathing apparatus - Google Patents

Abstract

482,492. Bourdon pressure gauges. DEGEA AKT.-GES. (AUERGES.). Aug. 3, 1937, No. 21421. Convention date, Aug. 15, 1936. [Class 106 (ii)] [Also in Group VI] In breathing-apparatus employing oxygen or other gas under pressure delivered through a pressure-reducing valve, warning of the exhaust of the gas supply is given by the provision, between a delivery nozzle for the gas and a whistle or other signal arranged opposite thereto, of a plate, having one or more apertures, and moved by a Bourdon tube connected to the high-pressure side of the valve, the plate normally diffusing the gas but permitting operation of the signal when an aperture in the plate registers with the nozzle. In the drawing, oxygen from a cylinder is delivered through a pipe 1 and a pressure-reducing valve 2 to a nozzle 5 arranged in a partition 5<1> in a connection 7 for a breathing bag 6. A whistle 14 is mounted on a bracket opposite the nozzle and is operated by the gas when permitted to escape through one of two slits 13 in a plate 12 which normally diffuses the gas. The plate 12 forms part of a lever 11 connected by a link 10 to a Bourdon tube 9, the tube being connected by a pipe 8 with the high-pressure pipe 1 and moving in accordance with the fall of pressure therein. The lever 11 may by pivotally mounted on a second lever rotatable about the nozzle 5 by a screw threaded rod against the action of a leaf spring in order to adjust the signal to operate at any predetermined degree of exhaustion. The plate 12 may have any number of apertures of the same or different widths to give a corresponding number of successive signals of the same or different periods. The whistle may be replaced by thin metal foil arranged to bend under the gas current and close an electric circuit including an optical or acoustic signal. Instead of the nozzle 5 the signal may be arranged to be operated by the jet of a lung operated valve 4 also mounted on the partition 5<1>.