GB781025A - Improvements in or relating to automatic shut-off valve systems for pressure indicators - Google Patents

Abstract

781,025. Pressure gauges. ARO EQUIPMENT CORPORATION. June 14,1955 [Dec. 6, 1954], No. 17067/55. Class 106 (2). To protect a manometer 48 against loss of the indicating liquid an automatic shut-off valve A is connected to its upper end and operated by pressureresponsive means 74 connected to its lower end. As shown applied to apparatus for testing the oxygen regulator 14 of an aviator's helmet, two manometers 56, 48 for high and low pressures respectively are connected in parallel by pipes 50a, 52, 54a, the valve A being fitted in the low-pressure pipe 52 and comprising a diaphragm 74 connected at 80 to a pipe 50b leading to the high-pressure pipe 50a and carrying a valve 66 adjustable by a screw 70 accessible by removing a screw plug 67. The oxygen regulator is placed in a chamber 12 capable of subjection to pressure or vacuum, and the hose 20 that is ordinarily connected to the aviator's helmet is connected to a suction source through a flowmeter 36. Oxygen is supplied to the regulator 14 from a cylinder 28 through a valve V<SP>0</SP>, and the chamber 12 is connected to the atmosphere through a flowmeter 46 and valve V<SP>3</SP> and to the low-pressure connection 54a by a pipe 54. If there is a leak in the oxygen regulator that increases the pressure in the chamber 12 above the maximum reading of the gauge 48 the valve 66 closes preventing loss of liquid through pipe 52, the high-pressure gauge 56 continuing to operate. A similar shut. off valve may be fitted in the pipe 54 to protect the manometer 56 against loss of liquid.