US 3036585 A
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Description (OCR text may contain errors)
May 29, 1962 E. N. SHAWHAN 3,036,585
FUEL DISPENSING SYSTEM Filed Aug. 8, 195s n4 ne A, |46
AMPLIFIER d Lloza' 8N S gt* gip-r rx' O u-I E 5% 'E INVENTOR. 3 rc3 ELBERT NEIL SHAWHAN A 'Q BY v ATTORNEYS cumulated price are all determined electrically.
This invention relates to a fuel dispensing system and has particular reference to a gasoline pump by which two fuel constituents are blended in desired proportions for delivery to the fuel tank lof a vehicle, with provisions for indication of total quantity delivered yand the price thereof.
Whereas it has long been customary for gasoline stations to provide separate pumps for the delivery of individual grades of gasoline, the grades being characterized by different octane ratings, there have more recently come into use arrangements whereby a single unit may deliver fuels of various grades, each comprising in definite proportions fuels drawn from two supplies one of which may, for example, contain a fuel of minimum usable octane rating while the other may contain a fuel of the highest desired octane rating or an additive which may not in itself be desirably marketed as a fuel but which, added in proper proportions to the basic fuel, may increase its octane rating to a desired degree. The devices in use for this purpose are mechanical, the proportions of the constituents which are to be delivered being determined by variable gear settings. Pricing may be elfected in various ways. For example, a price per gallon may be assigned to each constituent, and the quantity of that constituent delivered may be multiplied by the price and then the separate total prices added to arrive at the total value of the delivery. Alternative, and more satisfactory, is an arrangement by which the proportioning of the two constituents is effected to a high degree of accuracy so that the price may be arrived at by multiplying by a price per gallon the total volume of the blend delivered.
The general object of the present invention relates to the last mentioned type of operation in which the controlling of Ia blend, total gallons delivered and the ac- The advantages of such a system involve not only the elimination of mechanical complexity but also the possibility that the controlling and computing apparatus may be remote from the point of delivery and the control 4and computing apparatus may also be used to service various points of delivery. F or example, it is quite common that the actual delivery of fuel represents only a fraction of the time a vehicle may stand at a conventional pump, the remaining part of the time being consumed in such matters as checking oil and water, cleaning of the windshield, the giving of road information, etc. Thus, for a considerable portion of time an entire complete delivery and computing assembly is unavailable for its useful operation even though additional vehicles may be awaiting service. The complete controlling and computing assembly is expensive and hence it is not economical for a particular gasoline station to add pumps merely to take care of peak periods of demand such as may occur at certain times of day, on weekends, or the like. In accordance with the present invention, a major part of the apparatus involved in the proportioning and computing operation may be physically separate from the hose and associated devices immediately concerned with the delivery of fuel to a vehicle tank. By simple electrical switching a limited number of controlling and computing devices may be made available for connection to, and control of, a large number of delivery points. In fact, with additional valving under electrical control even the number of fuel arent Ffire pumps and associated meters may be reduced to a number considerably less than the number of servicing points.
Other objects of the invention particularly relating to details of construction and operation will become apparent from the following description, read in conjunction with the accompanying drawing, in which the figure indicates in diagrammatic form the mechanical and electrical elements involved in the invention.
Indicated in several portions of the diagram at 2 are conventional alternating power supply terminals provided with alternating current at conventional power frequency. These terminals 'are 4indicated only where they supply current to motor field windings or to a bridge arrangement hereafter described. It will be understood that the same power supply is used in conventional fashion for supplypower to amplifiers, etc.
Fuel delivery lines from a pair of fuel pumps are indicated at 4 and 6, one of these lines delivering the base fuel and the other the additive lwhich is to be mixed with the base to provide fuels of selected octane ratings. As is usual, the pumps supplying these lines are motor driven and provided with by-passes for flow so that the pumps may be operated even though delivery is stopped by the use of one or more shut-olf valves. In the lines 4 and 6 check valves 8 and l10 are provided preceding proportioning valves 12 and 14 which are mechanically interconnected and motor controlled so that las one is opened the other is correspondingly closed, the arrangement being desirably such that the total ow of both fuel constituents is approximately constant for a given setting of a manually controlled delivery valve. This, however, it not important, the important aspect of the arrangement being merely that of proportioning the fuel constituents in a desired volumetric ratio. Desirably, the arrangement is such that the valve controlling additive may be closed completely with the other fully opened so that the base fuel may be delivered alone. If the arrangement is such that the additive is also desirably delivered alone, consisting of the highest grade fuel which is to be delivered, then the arrangement is such that this can be accomplished by closure of the base-controlling valve while the additive valve is fully opened.
The lines `4 and 6 following the valves already referred to deliver their respective constitutents to meters 16 and 18 of conventional type for the accurate measure- Vment of ow therethrough.
Beyond the meters 16 and 18 are desirably shut-off valves 20 and 22 which are solenoid controlled by respective solenoids 42 and 44 connected in parallel across terminals 45. While not essential for various aspects of the present invention, each of these valve arrangements may desirably be of the type disclosed in my application, Serial No. 716,757, filed February 2.1, 1958, now Patent No. 2,918,095, issued December 22, 1959. As disclosed in lsaid `application each valve may be normally closed but opened upon energization of the associated solenoid, the
solenoid being automatically deenergized to shut olf the flow through both valves when the fuel level in the receiving tank rises to a predetermined extent detected by a capacitance provided in a delivery nozzle, the capacitance having an increase in its capacity value due to the action of the fuel as a dielectric between suitable plate elements. In this opera-tion, when the fuel in the receiving tank reaches a critical level the solenoids 42 and 44 are deenergized to close the valves 20 and 22 despite the continued open condition of a valve provided in the nozzle. Additionally, these solenoids are arranged to be deenergized when the number of gallons delivered or the accumulated price reach predetermined set amounts, as will be described hereafter.
Beyond the valves 20 and 22 the lines 4 and 6 are connected to the respective concentric hose conduits 24 and 26 wlhich deliver the fuel constituents to a delivery nozzle 28 provided with the manually controlled valve 30. The inner hose desirably terminates at 32 immediately preceding the valve 30 so that when the valve 30y is closed the hose connections will contain only a negligible quantity of the mixed'constituents. This is to avoid, fol-lowing one delivery, the delivery to a subsequent customer of a proportioned mixture which he has not called for.
What has been so far described is typical of the mechanically operating mixing pumps presently in use. There will now be described the novel aspects of the invention having to do with the electrical controls and computing devices.
The motor which controls the valves 12 and 14 is shown at 34 and the mechanical connections to these valves are indicated at 36. These `connections may include reduction gearing so that the motor may have fa relatively large movement for small adjustments of the valves. The motor is of reversible type comprising the field windings 38 and 40, the direction of rotation depending upon the relative phasing of the currents through these windings. The winding 40 is energized from the supply terminals 2.
The meter 16 is arranged to drive through a mechanical connection 46- including a disengageable and engageable clutch 47 the contact 50 of a potentiometer 54. In similar fashion, the meter 18 drives through a mechanical connection 48 including a clutch 49 the contact 52 of a potentiometer 56. These potentiometers may be of precision multiple turn type available on the market but are not connected as potentiometers but rather as rheostats by reason of the connections of the contacts 50 and 52 to respective ends of the potentiometer resistances. Accordingly, they provide variable resistors. They are joined at the terminal 58. The arrangement of the potentiometers is such that they may be manually zeroized desirably to minimum resistance values, by disengagement of the clutches 47 land 49 following each completed delivery of fuel. Then, by reengagement of the clutches 47 and 49 they may thereafter be driven by the respective meters. The variable resistors thus provided are involved in a plurality of bridges and receive excitation from terminals 2 through the connections 60 and 62 and the resistance 64 provided between connection 62 yand the lower end of the potentiometer 56. A diode 66 polarized as indicated connects the upper end of potentiometer 54 with the upper .terminals of a group of potentiometers such as 68, 68 and 68", there being a number of these potentiometers corresponding to the number of grades of fuel to be dispensed. Manually settable contacts of these potentiometers indicated as 70, 70 and 70 are joined respectively to switch contacts 76 with which ian adjustable arm 78 may be selectively engaged. The lower terminals of these potentiometers are similarly connected to the contact points 72 engageable by the switch arm 74 which is ganged with the arm 78 so that they simultaneously engage contacts corresponding to the lower terminals and adjustable contacts of the potentiometers. The switch arm 74 is connected to the lower end of potentiometer 56 at 80, the connection including the diode 82, polarized as indicated. As will be evident from the diagram, the potentiometers 68, 68 and 68" are energized during those half cycles of the supplied excitation Which involve Aa relatively positive potential at the upper terminal of potentiometer 54. The terminal 58 and the switch contact 78 provide an input to an amplifer 88 through the respective connections 84 and 86. This is an alternating current amplifier arranged to amplify, in particular, the component at the supply frequency which appears .at its input as the result of half-Wave rectification produced by the diodes 66 and 82 and the unbalance of the bridge. The amplifier 88 supplies current to the winding 38 of motor 34.
Considering the operation of the part of the circuit so far `described (which, as will more fully appear hereafter, is independent of operation of the remaining parts v64 and 100 merely providing a iixed scale ratio.
of the illustrated circuit), what occurs during a delivery of the fuel constituents is as follows:
Considering a particular setting of the switches 74 and 78 corresponding to a desired ratio of the fuel components which is to be delivered, it will be evident that the bridge will be balanced and a zero input delivered to the amplifier 88 only when the effective resistances provided at the potentiometers 54 and 56 have the same ratio as the resistances appearing above and below the adjusted contact of the potentiometer which is selected by the switches. When the ratio of the resistances at 54 and 56 is different, the winding 38 will be energized depending upon the direction of deviation from the ratio to effect drive of the motor 34 in one direction or the other, a phase reversal occurring as the output of the bridge passes through zero. The meters 1'6 and 18 adjust the resistances at 54 and 56 in linear accordance with the meter outputs, and the connections are so made that if the ratio changes from that set on one of the potentiometers 68 the motor 34 will operate the valves 12 and 14 in such direction as to readjust the iiows of the two constituents to bring the resistance ratios into proper correspondence to secure zero input to the amplifier. Thus, during a delivery operation the ratio of the fuel constituents delivered is maintained substantially constant, the motor 34 providing for rapid readjustment of the valves to attain this end. It will be noted that the operation is cumulative and not dependent on instantaneous rates of iiow, with the result that the total quantity delivered during an operation will be very close to that predetermined by the switch settings. Using preoision multi-turn potentiometers, accuracy well within the requirements of the law may be secured.
Reference may now be made to the part of the circuit providing a second bridge. As shown, the terminals Z connected to the leads 60 and 62 are respectively con-i nected at 90 and 92 through diodes 94 and 96 to the series arrangement of potentiometer 98, connected as a variable resistor, and fixed resistor which are joined at the junction 102. The diodes 94 and 916 are polarized as indicated, and it will be evident that these diodes con'- `duct current only when thephase of the supply is opposite that previously described, i.e., during the half cycles for which the upper end of potentiometer 54 is negative. The result of this polarization is that the portions of the circuit to the left of the diodes 66 and 82 are isolated, eifectively, when the diodes 94 and 96 are conducting and similarly the portion of the circuit to the right of the diodes 94 and 96 is isolated from the bridge previously described when the diodes 66 and 82 are conducting.
A motor 104 drives the contact of the potentiometer 98 to provide a variable resistance. Lead 106 connected to the junction 102 and lead 108 connected to the left hand end of resistor 64 provide the input to an ampler similar to amplifier 88, the amplifier 110 providing current to the winding 112 of reversible motor 10'4, the other winding 114 of this motor being energized from terminals 2. This motor 104 may be similar to the motor 34 previously described. The last bridge arrangement provides an output counting the gallons delivered. That this is the case is explainable as follows:
If the various connections are traced, it will be evident that a bridge is provided which in one of its arms contains the series resistances provided at 54 and 56, in a second arm the resistance 64, in a third arm the resistance 100, and in its fourth arm the variable resistance 98 adjusted by the motor 104. Balance of the bridge will exist when the ratio of the sum of resistances at 54 and 56 to the resistance at 64 is equal to the ratio of resistance at 98 to resistance 100. It will, therefore, be evident that the resistance at 98 is a measure of the surn of the resistances at 54 and 56 and, therefore, a measure of the total gallons of fuel delivered, the resistors at The motor 104 is driven by the output of the bridge to maintain balance by adjustment of the contact of potentiometer 98, which potentiometer should also be of precision multi-turn type. The motor 104 may drive a gallons counter 140 mechanically, and this counter will indicate the total gallons delivered during an operation. The counters should be of a type capable of accumulating in either direction, so that automatic zeroizing will occur at the beginning of each delivery operation. lf the layout of the service station requires, the counter 149 may be driven electrically from the shaft of motor 164 through a selsyn or similar servo system.
A third bridge arrangement very similar to the last is provided to secure an indication of total price of a delivery. For this purpose, the diodes 94 and 96 are joined through connections 116 and 118 to a further pair of resistances. One of these resistances is provided by the precision multi-turn potentiometer 12), the contact of which is connected to provide a variable resistance. The other resistance of this pair is provided by a selected one of a group of adjustable resistances 122, 122 and 122 connected to individual contacts 12d of a switch the movable arm 126 of which is connected to 118 and mechanically ganged to the switch arms 74 and 78. Adjustments of the resistances at 122, 122 and 122 provide for the settings of prices per gallon of the various mixtures which are to be delivered. The junction 130 between the potentiometer 1243 and the various resistances 122, 122 and 122 is connected at 132 to one input terminal of the amplifier 134, the other input terminal of which is connected through 103 and 193 to the left hand end or" resistor '64. This amplifier 134 has the same characteristics as the amplifiers 8S and 110 previously described and provides its output to one of the ield windings 136 of the reversible motor 128 which drives the adjustable contact of potentiometer 120. The other ield winding 138 of this motor is energized from the supply terminals 2. The motor 128 drives a reversible price counter 142 either mechanically or electrically as previously described in connection with counter 140.
The operation of the last described bridge is essentially the same as that of the second bridge which was described, except that in this case the resistor 109 which provided a lixed ratio is now replaced by one of the resistances 122, 122 or 122" which is selected and which has been set for the price per gallon of the mixture delivered. Balance is achieved automatically by operation of motor 128 with the result that its displacement corresponds to a factor representative of price multiplying the total gallons represented by the sum of the resistances at S4 and 56. Here also Zeroizing of the counter 142 is automatically elected by the automatic rebalancing of the bridge when zeroizing of the resistances at 54 and 56 occurs.
It is quite customary for customers to request either a specilic number of gallons of fuel or an amount of fuel corresponding to a specific price. Operation to stop delivery in either of these situations is simply provided by the arrangement of switches le@ and 146 adjustable relative to the potentiometers 9S and 12o so as to be opened when the movable contacts of these potentiometers reach predetermined points. These switches are included in the series connections to the valve solenoids (l2 and 44 to provide deenergization and closure of the associated valves. Alternatively, switching arrangements may be connected to the counters 14d and 142 to be opened when particular amounts are accumulated thereon.
As will be evident from the foregoing description, various selected portions of the circuit may be remotely connected with respect to points of delivery so as to minimize the apparatus at such points. The meters 16 and 18 may well drive electrically the potentiometer contacts 5t? and 52. The motor 34 may be located at the point of delivery with remote energization from its arnplitier `88. Great freedom of layout of the elements is thus afforded.
Furthermore, it will be obvious that with suitable switching the major components of the entire system may be provided in less number than the delivery points, with switching provided to make connections from any delivery point to a computing and control arrangement which may be, at the time, idle. This provides for the situation above mentioned wherein a particular delivery point may be tied up through the rendering of other services than the delivery of fuel. A minimum of installation at the delivery point may Ibe provided. With suitable piping and valving it is even possible to have a pair of meters service a number of delivery points.
What is claimed is:
l. Electrical apparatus for ycontrolling the llows of a pair of fluids so as to maintain them approximately in a preselected desired ratio, comprising a first lbalanceable circuit including a pair of adjustable impedances, means for adjusting said impedances as functions of the ows of the respective fluids, and means establishing a preselected ratio -for said impedances corresponding to balance of the circuit and corresponding to the preselected ratio of the tluid flows; means providing excitation 0f said circuit, means responsive to an output signal from said circuit for adjusting the relative tlows of said fluids, a second balanceable circuit including as one element thereof said pair of impedances in series, and as another element thereof an adjustable impedance for balancing said second circuit :for different values of said one element; means providing excitation of said second circuit, and means responsive to an output signal from said second circuit to adjust the last-mentioned impedance to balance said second circuit.
2. Apparatus according to Iclaim 1, wherein the means establishing a preselected ratio comprises one of a plurality of ratio-establishing means selected in accordance with the ratio of liuid flows desired.
3. Apparatus according to claim l, wherein said two means for excitation of the respective balanceable circuits comprise a common alternating current source, and rectifying means for exciting said respective balanceable circuits during opposite -half cycles of the alternating current.
4. Apparatus according to claim 3, wherein the means establishing a preselected ratio `comprises one of a plurality of ratio-establishing means selected in accordance with the ratio or' fluid ows desired.
5. Apparatus according to claim 3, wherein the second balanceable circuit includes as still another element thereof one of a plurality of impedances selected in accordance with the price assigned to the particular uid flow ratio selected.
6. Apparatus according to claim 5, wherein the means establishing a preselected ratio comprises one of a plurality of ratio-establishing means selected in accordance with the ratio of Huid flows desired.
7. Apparatus according to claim 1, wherein the second `balanceable circuit includes as still another element thereof one of a plurality of impedances selected in accordance with the price assigned to the particular fluid ilow ratio selected.
8. Apparatus according to claim 7, wherein the means establishing a preselected ratio comprises one of a plurality of ratio-establishing means selected .in accordance with the ratio of fluid ows desired.
9. In combination, means including a circuit having a pair of adjustable impedances Vfor controlling the flows of a pair of uids so as to maintain them approximately in a preselected desired ratio; a balanceable circuit including as one element thereof said pair of adjustable impedances in series, and as another element thereof an adjustable impedance for balancing said last-mentioned circuit rfor dierent values of said one element; said firstmentioned means including also means for adjusting said pair of impedances as functions of the flows of the respective uids; means providing excitation of said Ibalanceable circuit, and means responsive to an output sig- 7 nal from said balanceable circuit to adjust the balancing impedance to balance said last-mentioned circuit.
References Cited in the le of this patent UNITED STATES PATENTS 843,814 Hewlett Feb. 12, 1907 2,252,368 Germer Aug. 12, 1941 2,428,382 Prangley Oct. '7, 1947 Dean June 8, 1948 De Gers Ma-y 30, 1950 Goddard Jan. 6, 1953 sserstedt Mar. 23, 1954 Walker Feb. 12, 1957 Hollenbach Apr. 8, 1958 Young Oct. 28, 1958 Kolisch Feb. 10, 1959