GB1019956A - Improvements in or relating to fluid flow control valves - Google Patents

Abstract

1,019,956. Valves. MINISTER OF AVIATION. Oct. 22, 1964 [Oct. 24, 1963], No. 41991/63. Heading F2V. A valve for controlling the supply of oxygen to a breathing apparatus comprises a housing having an inlet 14, the Figure (not shown), leading to a tube 13 which opens into chambers 11 and 12. Each chamber is bounded by a diaphragm 16, 17 which can seat on the tube 13 to close the supply. The diaphragms are rigidly connected by rod 18 so that one valve is open while the other is closed. A spring 20 acts on the diaphragm 17 and the rod 18 is connected to a button 19. The chambers 11, 12 each have an outlet 21, 23 and the chamber 12 is also connected to a second supply sourec 26 controlled by a valve 27. In operation, with the valves in the position shown flow tubes place from supply 14 through chamber 11 to outlet 21 and the pressure acting on diaphragm 16 holds the valves in the position shown. If the supply 14 fails, the valve 27 is opened and flow tubes place through chamber 12 to outlet 23. The increase in pressure in the chamber 12 acts on the diaphragm 17 to close the lower end of the tube 13 and open the upper end, a non- return valve 15 preventing flow through the line 14. When the pressure in line 14 is restored, it now flows through chamber 12 and closes a non-return valve 29. The valve can be reset to the position shown by closing valve 27 and pushing down on the button 19.