EP0024377A2

EP0024377A2 - Device for controlling, indicating and metering quantity and price of transferred liquid

Info

Publication number: EP0024377A2
Application number: EP80302865A
Authority: EP
Inventors: Froie Edwin Tessier
Original assignee: Gilbarco Australia Ltd
Current assignee: Gilbarco Australia Ltd
Priority date: 1979-08-20
Filing date: 1980-08-19
Publication date: 1981-03-04
Also published as: EP0024377A3; AU6152480A

Abstract

The present invention is directed towards the provision of a metering means which is particularly adapted for use with mechanical petrol pumps; there is provided an electronic metering means for a petrol pump comprising a flow meter connecting means (11), signal generating means (6) operable by said connecting means to generate a first electrical signal representative of the volume of petrol flow, price per unit of petrol flow control means (7) to provide a second electrical signal representative of the cost per unit volume, means (7) for generating a third electrical signal separating the product of the first and second electrical signals, indicating means (8) to receive the said third electrical signal and provide a required indication of the cost of the petrol supplied; display means (9) connected to the first electrical signal indicate the volume of petrol dispensed; magnetic means are provided to keep the displays set at their last value even when actuating signals or power are not present; circuitry provides slowing down of the pump-motor as the amount of petrol dispensed approaches an even dollar value or a preset value and then switching off the pump-motor when the required value is reached.

Description

The present invention relates to improvements in and relating to metering systems.
More particularly, the present invention relates to the metering of petrol flow from a petrol pump and computing the charge for that petrol.
Since the oil crisis in 1973 large increases in retail petrol prices have created many problems, one major problem being the affect of higher price settings on mechanical petrol pump computers.
Each upward movement of a price setting range on its mechanical price cone gear results in an increased mechanical resistance in the computer which must be overcome by the flowmeter immediately below the computer. With each price increase the speed of the money wheels also increases.
The problems caused by these increasing retail petrol prices on mechanical petrol pump computers can therefore be summed up as (a) an increased damage to the money wheels and (b) an increased requirement for recalibration of the flow meter.
Both these major problems have direct financial consequences for pump owners and service station operators in that both (a) cost money to remedy, (b) cause unscheduled pump downtime and (c) overmeasure means undercharging for petrol issued.
Answers to the above problems have been searched for internationally and apart from reducing or at least holding the retail price of petrol two solutions to these problems are in use and two others have been suggested. These four solutions are:

1. To remove the computer from the pump
2. to use a mechanical computer with double transfer wheels
3. to slow down the pump
4. to use an electronic dispensing pump.

Dealing with the first of these solutions, the removal of the computer from the pump creates difficulties in calculations of the charge, to arguments with petrol station customers, to a slow down in station throughput and additionally in the practice of purchasing fuel by money value rather than volume.
Dealing with the second of these solutions the use of a double transfer wheel reduces the speed of the money wheel and damage to the wheels is therefore reduced. However, the problem of increased torque is not resolved and calibration problems still persist.
Turning now to the third solution the slowing down of the pump reduces the pumps effectiveness and also volume throughput and some major petrol service station installations it is believed could with such a solution become marginal or in-operable.
Turning to the final of the above solutions the use of electronic pumps does directly tackle and solve both the increased torque and increased money wheel speed problems. However, electronic pumps available have the major disadvantages of both high pump costs and also a reduced pumping speed which reduces the cash return potential per pump per minute.
The above solutions therefore to the present time at the best only partially solve the problem outlined above.
The present invention is therefore directed towards the provision of a metering means which is particularly adapted for use with mechanical petrol pumps and in such use would obviate the problems of previous systems to the present time. According to one embodiment of the present invention there is thus provided an electronic metering means for a petrol pump comprising a flow meter connecting means, signal generating means operable by said connecting means to generate a first electrical signal representative of the volume of petrol flow, price per unit of petrol flow control means to provide a second electrical signal representative of the cost per unit volume, means for generating a third electrical signal representing the product of the first and second electrical signals, indicating means to receive the said third electrical signal and provide a required indication of the cost of the petrol supplied.
The present invention will now be described by way of example and with reference to one possible embodiment thereof which is shown in the accompanying drawings wherein;

FIGURE 1 : shows schematically and diagrammatically, an electronic metering means according to one embodiment of the invention in block diagram form.
FIGURE 2 : shows, diagrammatically, a front perspective view of the electronic metering means according to one embodiment of the invention.

The present invention can broadly be said to comprise an electronic computing head, suitably using solid state microprocessor circuitry, which is adapted for use with a mechanical petrol pump and represents in such use a direct replacement for the mechanical computer heads used to the present time.
The electronic computing head of the present invention is adapted or is readily adaptable, to be compatible with all types of flowmeters used in petrol pumps particularly the four to one and two to one flowmeters presently in use.
The computing head of the present invention will generally include the visual read out from both sides of the pump which largely comprises the only similarity between this present invention and what is presently used.
Basically, the present invention comprising the electronic computing head is operably connected to the flow meter which is driven by the fuel passing through it, a drive generally off the top of the flowmeter being connected to the base of the present invention.
The flowmeter connecting means of the present invention will in turn be connected with a signal generating means which may suitably comprise a slotted disc which as it is caused to rotate interrupts a light beam. This interruption is detected by a photo electric cell connected into a pulse generating circuit, the pulse train generated thereby thus being representative of the volume of petrol flow through the petrol pump and the movement of the flowmeter caused thereby.
The pulse train is then caused to provide a volume display and, in conjunction with a price per unit volume control means, also a cost display, the cost and volume displays continually changing during the delivery until completion of the delivery when the final volume and cash amounts are held until a resetting occurs for the next delivery.
Regulations in most countries usually require that a resetting to zero of the displays occurs before any fuel can be delivered and in conventional systems with a mechanical computer this is achieved by a series of levers or linkages. These linkages start the pump motor and operate a delay valve which remains closed until the mechanical computer is reset. These linkages are of course subject to constant use and can rapidly misalign themselves, the delay valve also being subject to wear and can stick if any slightly dirty fuel is in the station's tanks. These faults in previous systems do result in pump down time and unnecessary expense.
In contrast, the present invention may essentially eliminate the previous mechanical linkages although in one embodiment thereof may have a single mechanical linkage from a lever in the nozzle boot which operates the resetting means in the computer when the nozzle is removed from the nozzle boot. In this embodiment the segmented displays will all operate, generally flashing a single numeral together, and a timed delay sequence, for example of about 15 seconds may then be started. At the completion of this time delay the logic system of the present invention will then start the petrol pump motor, the timed delay sequence statisfying the regulations previously mentioned in ensuring that the pump is reset before a delivery can commence. The lack of power to the pump motor until it is needed to operate the pump obviates the provision of the customary delay valve and the electronic control sequence obviates the necessity to provide the mechanical linkages to the delay valve and the motor. It is to be appreciated that this elimination of now unnecessary components, which components are subject to failure, will be of considerable advantage in substantially reducing pump downtime.
When fuel is being dispensed both the volume and cash totals will continually increment visually on the respective displays and when the nozzle is stowed in the boot the last figures may be retained until the nozzle is removed from the nozzle boot for the next delivery. The displays may hold their last figures indefinitely if the resetting of the present invention is not effected. Unlike electronic pumps presently operating the displays of the present invention may be magnetically operated for example with mechanical seven segment displays, permanent electromagnets holding the display until an electric current passes through the coils behind the display units. An advantage of such a system is that even in the event of total power loss the displays will hold their last readings without the need for a battery back-up system, this resulting in a much simpler unit that provides for a permanent display. Totalizers, for example of an electromechanical type may also be included in the display to show accumulated volume and cash throughput through the petrol pump. These totalizers may be relatively smaller units and positioned on each side of the present invention with permanent displays and may be sealed for example under a Weights and Measures seal to ensure tamper-proof recording.
The price setting on the present invention is able to be effected in a simple and effective manner which is in direct contrast with the previous range arm system used on the mechanical computers to the present time.
The price setting of the present invention may suitably comprise a sequence of thumb wheels which can be readily turned by an operator's thumb to give a required setting, for example four thumb wheels may allow a maximum price setting of $9.999 per litre. The present invention will generally have the cost and volume displays and also the thumb wheels for other price setting means provided on both sides and in the event that the price setting on both sides is not the same before a delivery is attempted then the unit may be suitably provided with protection means whereby the pump will remain inoperable and the displays may suitably flash. This preferably automatic inbuilt feature would of course safeguard both the motorist and the service station proprietor. Should an unscrupulous attendant attempt to alter the fuel price during delivery the pump will enter the same fault mode and will not operate until the prices are correctly set on both sides. After a price adjustment a delay, for example of the order of one minute, sequence may be entered so as to ensure that no fuel can be delivered accidentially before the computer head of the present invention confirms that the prices are correctly set. An additional feature that may readily be incorporated into the present invention is what can be termed a "rollover" protection whereby should any user of the pump try to dispense more than for example 999.99 litres or $999.99 worth of fuel through the pump, the present invention will enable the pump motor to be rendered inoperable until a resetting operation has been carried out.
The logic circuitry of the present invention as aforementioned suitably uses well known solid state micro processor techniques and together with all power sources may suitably be provided within a flame proof die cast aluminum housing so as to comply with dangerous goods requirements and for the same purpose the displays are suitably contained within gas proof enclosures fully sealed against the unlikely event of vapour concentration in this area of the pump. In that the present invention is associated with a constant low torque loading even at very high price settings, the previous aforementioned problem associated with the holding of calibration of mechanical computers is substantially obviated. Additionally, the present invention enables a much more accurate calibration to be made in that by the provision of a calibration switch the decimal point on the volume wheels may be taken one digit to the left allowing volumes to be read in millilitres. Accordingly the pump may then be very accurately calibrated for example to within three millilitres in 20 litres a significant improvement on currently available calibration.
Furthermore, the present invention may be provided with an in-built Weights and Measures test sequence whereby switching to this mode allows a Weight and Measure inspector to test the calculating ability of the present invention at various price settings, the invention for this purpose being programmed with several pre-recorded deliverys. When the reset mechanism is operated in this mode the display will show one of these final deliverys and the cost of the delivery calculated from the price set per litre. The inspector can then use his own calculations to check that the cost shown is correct. By varying the cost setting the inspector can satisfy himself that the unit is functioning properly throughout its full range of price setting, each resetting operation bringing in a new volume value thereby fully testing the unit throughout the range.
In an alternative embodiment the present invention may be associated with a suitable valve arrangement, for example a solenoid valve and slowdown valve assembly, to enable a preset operation if this is required. With such operation the selected value of the petrol to be dispensed will be shown .on a display and the pump will then be operated in the normal manner until the pump gets to within a small cost value of the preset value when the slowdown valve will operate such that the slowed down delivery will enable the final shut-off to be made smoothly and without throwing any strain on the pump. In such a preset operation sequence the operator would be able to stop delivery before the preset value is reached merely by hanging up the nozzle which will stop the pump and reset the preset to zero.
Another alternative feature is the automatic sensing of flow rate near to even values of money units (such as dollars) or volume units (such as litres). This allows the user to more easily "shut off" at even amounts, irrespective of the use of the "preset" arrangement of the previous paragraph.
In both the "preset" and the "even value" arrangements shut off is achieved without a value in the hydraulic systems. This is done by controlling the pump-motor speed.
For example when the operator sees the cost approaching say an even dollar he will slow down the flow by hand. This slowing of the flow is electronical-ly sensed and the motor is then automatically controlled to slow the flow and cut it right off when the next even dollar is reached.
Referring now to the accompanying drawings, Figure 1, shows, schematically in block diagram form one possible sequence of connections untilized for the electronic computing head of one embodiment of this invention.
Thus there is indicated in Figure 1 an electrical switch 1 which is closed upon removal of the nozzle P from the nozzle boot, the closing of the switch 1 switching on a timer circuit 2 which will provide a suitable delay, for example of the order of 15 seconds, before connecting power to the pump motor 3.
The fuel pumped by the pump motor 3 and flowing from the pump nozzle P will cause the operation of the flow meter 4 which is then connected to the electronic computing head of the present invention as indicated by the flow meter connection 5 and signal generator 6.
The signal generator 6 will provide a signal suitably in the form of a pulse train which is representative of the volume of fuel being dispensed.
The signal from signal generator 6 provides an input signal to a volume display 9 and, in conjunction with a signal from the setting of a price per unit control 7, a further signal is produced and fed to a cost display 8.
The cost and volume displays 8 and 9 will show increased values consistent with the increasing volume of fuel as it is dispensed and when fuel flow has ceased will be held until subsequent resetting to zero when the next fuel delivery commences with the pump nozzle P again being removed from the nozzle boot.
Referring to the displays 8 and 9 these, as previously mentioned are suitably magnetically operated with mechanical segments being attracted and repelled so as to provide the appropriate display. Magnetic remanence holds the segments in their last set position when the actuating signal is removed, either in normal operation or say in the event of a power failure. This arrangement provides a system of data rentention without a battery back-up.
To the present time this attraction and repelling of magnetic segments in a display has been associated with a corresponding charging of a capacitor which when the display is to be cleared is discharged.
It has been found that such capacitor discharge arrangements prove unreliable and thus the present invention also provides in one preferred embodiment thereof a driver circuit for a magnetic display. This driver circuit includes a triac and logic switching circuit connected across a bipolar supply which allows the capacitor discharge circuitry previously used to be discarded in that the triac driver circuit allows the drive to the magnetically operated displays 8 and 9 to be switched to a required polarity depending on whether a display is being set or reset.
Accordingly this embodiment of the invention thus provides a drive circuit for a magnetically operated display including a bipolar voltage supply means and bipolar switching means connected thereacross to provide an appropriate signal to segments of the magnetic display dependant on whether the segments of the display are to be set or reset.
Referring to Figure 2 a flameproof housing, for example an aluminium casting 10, includes an input drive 11 along arrow A from a flow meter (not shown), the drive 11 causing, in this embodiment shown, the rotation of a disk 17 having a plurality of slots 18, the rotation of the disk 17 causing the interruption of a light beam which in turn causes the generation of pulses representative of the rotation of the disk 17 in a suitable electronic pulse generating circuit (not shown) suitably using solid state microprocessor techniques.
It is to be appreciated that the housing 10 will be positioned at the top of a petrol pump with a pair of display supports 14 facing outwardly on either side of the petrol pump and through appropriate windows in the petrol pump frame, exposing on either side, cost displays 15 and volume dispensed displays 16.
Also exposed through appropriate windows in the petrol pump framework on either side thereof is a price per unit display which in the example shown comprises numbered disks 12 rotatable by thumb wheels 13 which can readily be turned by the operator's thumb to give the required setting and which in conjunction with the decimal point which will be included on the pump framework itself may show a maximum price setting e.g. of $9.999 per litre. This price per unit setting in conjunction with the signal representative of the volume of fuel being dispensed enables the appropriate value to be indicated on the cost displays 15 together with the equivalent volume on the volume displays 16.
The electronic circuitry included within the housing 10 may suitably include a check on the settings of the price per unit controls such that both must be the same otherwise the fuel pump would be rendered inoperable.
The displays themselves may suitably as mentioned comprise electromagnets which will hold the display at the end of one delivery until being reset to zero by the commencement of a second delivery.
It will be seen that this facility in the present invention of speedily and effectively changing the price per unit value of the fuel being dispensed will obviate those problems hereinbeforementioned inherent in the previous mechanical computers with their price cone gearing.
Where in the description reference has been made to specific components or integers having known equivalents such equivalents are herein incorporated as if individually set forth.
Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that modifications and improvements may be made thereto without departing from the scope or spirit of the invention.

Claims

1. Electronic metering means for a petrol pump comprising a flow meter connecting means, signal generation means operable by said connecting means to generate a first electrical signal representative of the volume of petrol flow, price per unit of flow control means to provide a second electrical signal representative of the cost per unit volume of petrol, means for generating a third electrical signal representing the product of the first and second electrical signals, indicating means to receive said third electrical signal and provide a required indication of the cost of the petrol supplied.

2. Electronic metering means as claimed in Claim 1 wherein indicating means are also included to receive the first electrical signal and provide a required indication of the volume of the petrol supplied.

3. Electronic metering means as claimed in Claim 1 or 2 wherein the indicating means comprise electrical pulse operated magnetic actuating means which move visual display panels.

4. Electronic metering means as claimed in Claim 3 wherein magnetic remanence in the magnetic actuating means causes the display panels to remain in their set positions when the magnet actuation is absent.

5. Electronic metering means as claimed in Claim 1 or 2 wherein means are provided for slowing down the pump-motor when the value of the petrol dispensed approaches an even dollar or other denomination or approaches a preset value and also to stop the pump-motor when the even dollar or preset value is reached.

6. Electronic metering means as claimed in Claim 1 or 2 wherein the removal of the nozzle from the nozzle boot actuates means to reset the indicating means and means to initiate a time delay to prevent the pump-motor from starting before the resetting of the indicating means.

7. Electronic metering means as claimed in Claim 1 or 2 wherein the price per unit of flow control means comprises a sequence of thumb wheels having the price displayed thereon and wherein variation of the thumb wheels varies the second electrical signal.