GB850603A - Improvements in or relating to pumping systems for dispensing volatile liquid - Google Patents

Abstract

850,603. Dispensing petrol. TOKHEIM CORPORATION. June 13, 1957 [June 13, 1956], No. 18758/57. Class 116 [Also in Group XXIX] Dispensing petrol. A pumping system for dispensing volatile liquids such as petrol from a storage tank comprises a first motor-driven pump adjacent the tank delivering liquid to a second motor-driven pump at the point of delivery, the first pump being started automatically on starting of the second pump. As shown, after removal of the dispensing nozzle 67 of a petrol pump 71 from its hook 75, a switch 77 may be closed manually to start an electric motor 31 driving a pump 29 and simultaneously by means of a relay (not shown) to start a motordriven pump unit 3 in the storage tank 1. While the manually-operated nozzle 69 is kept closed petrol from pump 29 will circulate via chamber 37, Fig. 4, piston-operated valve 35 and the pump suction chamber 39. Any petrol which passes through the air vent 41, Fig. 4, is returned via a float-operated valve 47 to the chamber 39. Opening of the nozzle 69 causes reduced pressure in the line 27 which in turn causes reduced pressure in chamber 91, Fig. 3, of a control valve 25, causing a diaphragm 89 to move against the pressure of a spring 107 and open a valve 103. This allows pressure fluid, supplied by the pump 3 through conduit 26, chamber 83 and restricted orifices 87, to escape from chamber 85, causing a second diaphragm 81 to move downwards and open valve 99, whereupon fluid can flow directly from chamber 83 to chamber 91. A restricted air vent 95 damps oscillations of the diaphragm 89. If the line 27 is broken by impact of a vehicle, the break occurs at the weak point 30 and any suction in the line is removed thereby closing the control valve 25. The electrical connections are arranged so that pump 3 may be switched out and the system used in the normal way. If the pump 3 is of the positive displacement type this involves having a suction line 223, Fig. 1, then closing valve 23 and opening valve 225. Where the storage tank is above ground level an additional control valve 25 may be provided adjacent the tank, which valve may, in the case of only one dispenser, be alternative to the control valve under the dispenser.