Patent GB-1452353-A (GB)
Title: Liquid dispensing apparatus
IPC: B67D7/22
Filed: 1974-05-14
Abstract: 1452353 Photo-electric flow measurement TOKHEIM CORP 14 May 1974 21275/74 Heading G1A [Also in Division G4]  Liquid dispensing apparatus comprises: a manually-operated nozzle valve; a motor-driven pump; a mechanical flowmeter driving an electrical pulser; an electronic store and calculator; data transmission means; counters and numerical displays; and zero resetting means. A fuel dispenser 1 on a service station island 2 includes a motor-driven pump 7, 6 for delivering fuel to a nozzle valve 3 via a mechanical flowmeter 8. A seven-bar numerical display 15 presents gallons-dispensed to four figures, a corresponding four-figure delivery cost, and a three-figure unit price on which the delivery cost is calculated. A computer 10 in the station building 11 processes data derived from a pulser 9 coupled to the flowmeter 8 and supplies the display 15 with signals based on a unit price predetermined by setting manual controls 12, 13, 14 on the computer 10. A handle 4 on the dispenser 1 actuates a pulser switch 5 for resetting the fuel-dispensed and delivery-cost displays to zero before the next delivery begins. The flowmeter pulser 9 comprises, Fig. 6, an apertured disc 63 illuminated by two LEDs 61, 62 and scanned by two phototransistors 64, 66 positioned to be alternately illuminated. Phototransistor output pulses are given more precise definition by a pair of NAND gates 65, 67 in bi-stable connection. Flowmeter pulses, representing 0.001 gallon increments, enter a computer correlator Fig. 4 comprising three divider units 31, 32, 33 in divide-byten cascade, each arranged to supply pulses at any rate from zero to nine for every ten input pulses, according to the position of a respective selector 12, 13, 14 manually set to a digit of the unit price, e.g. 27.9 cents. An arrangement of NAND gates 34-37 combines the divider outputs, feeding pulses representing 0.1-cent increments to a decade divider 38 arranged to round off the cost to the nearest cent, by producing a pulse every time the number of 0.1-cent increments passes an odd multiple of five. To ensure that the delivery cost display shall not change in the intervals between 0.01-gallon fuel-dispensed increments, pulses from the divider 38 are stored in a bi-stable circuit 39, 40, from which they are gated by the next 0.01- gallon incremental pulse obtained from the divideby-ten terminal C of the first divider unit 31 and applied to a gate 42. The fuel-dispensed and delivery-cost pulses are counted and stored in respective four-figure decade counters of the computer (23-26 and 43-47), Fig. 2A, (not shown) which further encode the information in a form suitable for a seven-bar numerical display. Similarly, three-figure unit price signals are generated by encoders (117-119) Fig. 2 (not shown) responsive to the settings of the correlator selectors 12-14. The coded outputs of the two four-figure counters and the three-figure encoders are converted to serial form by parallel/serial converters (50-53, 27-30 and 47-49) gated by a clockpulse generator (56). The resultant 77-bit serial data, and pulses from the clock generator, are transmitted by respective conductors of a twowire transmission line from the computer 10, Fig. 1 to the display 15, where serial/parallel converters (70-80) Fig. 3, (not shown) followed by drivers (81-91) energize respective digits (92-102) of the seven-bar numerical display.