GB841026A - Device for sensing and indicating changes in flow conditions in a fluid pumping system - Google Patents

Abstract

841,026. Indicating vibrations. BRITISH OXYGEN CO. Ltd. June 26, 1958 [June 26, 1957], No. 20152/57. Class 106 (4). [Also in Group VI] Apparatus for sensing and indicating changes in flow conditions in a fluid pumping system comprises a pump 3 actuated by pressure fluctuations in the system, a reservoir 7 pressurized by the pump 3, pressure-responsive bellows 7 movable in response to pressure changes within the reservoir 7 and signalling means B operated by the bellows 7 to indicate relevant changes in flow conditions. The pulsating pressure in the pumping system is applied through inlet 6 to a chamber 4, causing a diaphragm 2 to fluctuate and so pump gas from chamber 3 to bellows 7 through a non- return valve 9. Gas pressure in the bellows 7 is relieved through a passage 11 and narrow bleed 12 which discharges into a bag 13 of such volume and flexibility that its internal pressure remains substantially atmospheric, while a second non-return valve 14 permits gas to flow from the bag 13 through a passage 15 to the pump chamber 3. The free end of the bellows 7 operates, through a push-rod 16, a microswitch in an alarm circuit, which can be held open only so long as a sufficient pressure is maintained in the bellows 7 by the pumping action of the diaphragm 2 and this will fail and cause the alarm to be given after a period of time in a number of different conditions. The projecting end of the inlet 6 and annular projection 10 surrounding the passage 8 each act as stop limiting movement of the diaphragm 2 and the guide bush 17 limits movement of the bellows. The supply system may be of gas to an artificial respirator or of fluid to tools in automatic processes.