GB898468A - Gas dispensing apparatus - Google Patents

Abstract

898,468. Respiratory appliances. MINE SAFETY APPLIANCES CO. March 31, 1959, No. 10876/59. Class 81 (2). [Also in Groups XIX and XXIX] A pressure-reducing valve for dispensing gas, e.g. oxygen for breathing, at low pressure from a high-pressure container 2 comprises a highpressure chamber 12 connected by a conduit 14 with the container, a low-pressure chamber 16 connected by a restricted passage 60 with an outlet 17 and containing a flexible diaphragm 36 loaded by an adjustable spring 45, and a valve closure member 25 controlling communication between the chambers 12, 16 by cooperation with a seat 19 of moulded plastic or other material. The valve member is urged towards its closed position by a spring 30 acting through a ball 31 and has a stem 24 against which abuts a head 32 of an actuating rod 33 secured to the diaphragm 36. The passage for gas between the chambers 12, 16 is through the clearance between the valve stem 24 and holes in the seat 19 and in a threaded plug 18 and also through a passage 22 in the plug 18, and the effective cross-sectional area of the passage between an intermediate chamber 23 and the chamber 16 is at least equal to and preferably greater than the cross-sectional area of the passage 60. The spring 45 is adjusted by rotation of a screw-threaded knob 40 having a spring-loaded plunger 70 which engages recesses 73 so that an operator may feel various positions of adjustment. To obtain a large rate of flow in an emergency a lever 50 carried by the knob may be operated to depress the rod 33. The conduit 14 communicates with a charging fitting 5, a main shut-off valve (not shown) and a fusible safety plug (not shown). The container is fitted with a pressure indicator 81 as described in Specification 898,469.