GB1438164A - Liquid dispensing apparatus - Google Patents

Abstract

1438164 Dispensing liquids LLEWELLYN LEWIS Ltd 16 May 1974 [21 June 1973] 29573/73 Heading A4T Blending dispensing apparatus e.g. for petrol comprises flowmeters 3, 4 for measuring the flow of two respective constituents, a stepping motor (not shown) for simultaneously operating valves controlling flow of the constituents so that rotation of the motor in respective direction increases or decreases the proportion of one constituent, and a control circuit for actuating the motor in accordance with processed pulses from the meters 3, 4. If, for example, a blend of 75%:25% high octane: low octane petrol is to be dispensed, the number 25 corresponding to the low octane percentage is set into a memory 1. With the valves correctly set, the high octane meter 3 will produce 3 pulses for every one from the low octane meter 4, and a total of four pulses per low octane pulse will be summed by an OR gate 7 and fed to a logic circuit 9. The input from the gate 7 is multiplied by the number from the memory 1 to produce an output of 100 pulses per low octane pulse, which is divided by 100 by a divider 11 and fed to a logic circuit 12, having two outputs 13, 14 for respectively stepping the motor and determining the direction of movement. If the pulse frequency output of the divider 11 is greater than the pulse output of the meter 4, indicating an excess proportion of high octane petrol, the motor will be actuated to increase the low octane proportion, whereas a lesser output will actuate the motor in the opposite direction to increase the high octane proportion. Identical outputs will result in stepping of the motor in alternate directions as the pulses are received, to maintain a uniform overall blend ratio. The output of the gate 7 also actuates a counter 15 for operating displays at the dispensing point and a central station, indicating the quantity dispensed, and governs a line 25 for terminating dispensing if a maximum allowed volume is reached. It is also fed through a settable divider 16, set according to whether the petrol is priced e.g. by the gallon or the litre, to a second logic circuit 19 having a memory 2 into which the unit price is set, the circuit producing an output for controlling a total price display. Lines 23 may further be provided to enable the incorporation of means for setting the apparatus to dispense petrol to a given total price or for the inclusion of a note validator.