WO2001033386A2

WO2001033386A2 - Inventory management system and method

Info

Publication number: WO2001033386A2
Application number: PCT/CA2000/001232
Authority: WO
Inventors: John Robert Lowndes
Original assignee: Timeline Technology Inc.
Priority date: 1999-10-29
Filing date: 2000-10-27
Publication date: 2001-05-10
Also published as: AU7896600A; WO2001033386A3; CA2288396A1

Abstract

An inventory management system and method for consolidating fuel inventory in a storage tank with fuel sold by one or more fuel pumps. The system determines a delta corresponding to determined differences between changes in the volume of fuel stored in the storage tank and the volume of fuel reported as being delivered from one or more fuel pumps supplied from the storage tank. These deltas are stored and are used by a consolidator to produce a corrected consolidation of inventory. Deltas are stored for each pump and can also be stored for combinations of simultaneously operating pumps. The consolidator can also employ the deltas to produce an error corrector factor for each pump, which factor can be applied to the pump to correct and reduce the delta. The consolidator can be located at the same location as the storage tank and pumps or can be remotely and connected to the site by a network, telecommunication link or the relevant information can be provided to the consolidator via physical means, such as a disk, tape, etc.

Description

Inventory Management System and Method

FIELD OF THE INVENTION

The present invention relates to an inventory management system and method. More specifically, the present invention relates to a system and method for managing and controlling the inventory of a fueling station, such as a motor vehicle fuel sales station.

BACKGROUND OF THE INVENTION

Motor vehicle fuel sales stations, or service stations, are well known. In fact, many tens of thousands of such stations exist within North America alone. One important aspect of the operation such stations is the management of their inventory, i.e. - the fuel to be sold. This inventory management comprises several aspects, including ensuring that adequate inventory is on hand and monitoring the condition and/or operation of facilities such as tanks, pumps, etc. to ensure that leakage, mis-measurement and/or employee theft is reduced or eliminated.

To date, inventory management at service stations has largely consisted of reconciliation between the amounts of fuel in inventory and the total amounts sold. Records are kept of the total volume of a fuel delivered to a storage tank at a station, the total volume of fuel in the tank and the total volume of the fuel sold. Theoretically, it is possible to reconcile these volumes to a high degree of accuracy and, in fact, in many jurisdictions such an accurate reconciliation is required by regulators to identify unacceptable losses due to leakage and/or venting of the tanks and/or inaccuracies in the sales pumps. However, due to a variety of reasons, it is generally not possible to reconcile fuel volumes to the desired, or required, degree of accuracy. Some of the reasons for inaccurate reconciliations include differentials in the temperature of the fuel in the storage tank and at the sales pumps, drift or errors in the calibration of the sales pumps, losses due to leakage from the tanks and/or delivery pipes, errors in tank volume measurement, etc. As the cost of inventory (fuel costs) have steadily risen over the last decade, inaccurate reconciliations result in increased costs or losses by the operator of the service station. Perhaps more importantly, inaccurate reconciliations can result in leakage being undetected for unacceptable time periods, resulting in economic losses and environmental damage.

It is therefore desired to have an inventory management system and method which allows more accurate reconciliations to be obtained. SUMMARY OF THE INVENTION

It is an object of the present invention to provide a novel method and system for managing and/or reconciling an inventory which obviates or mitigates at least one disadvantage of the prior art. According to a first aspect of the present invention, there is provided a fuel inventory management system comprising: a probe to determine the volume of fuel in a storage tank; at least two fuel sales pumps each operable to deliver a volume of fuel from said storage tank to a consumer and to measure said volume of fuel delivered; at least two accumulators, each accumulator operable to store data representing the measured delivered volume from each respective pump; a consolidator operable to determine differences between changes in volume indicated by said probe and said measured delivered volumes from said at least two accumulators for each of said at least two fuel sale pumps; and a storage device to store said determined differences, said consolidator operable to employ said stored determined differences to create a corrected consolidation between volume changes in said storage tank and fuel volumes delivered by said at least two fuel pumps.

According to another aspect of the present invention, there is provided a method of managing fuel inventory at a fuel delivery station including a fuel storage tank and at least two fuel delivery pumps, comprising the steps of:

(ii) determining a volume of fuel indicated as being delivered by at least one of said at least two fuel pumps;

(iii) determining the change in volume of fuel stored in said storage tank supplying said at least one fuel pump; (iii) determining and storing a delta representing the difference between said determined volume of fuel indicated as being delivered by said at least one fuel pump and said determined change in volume of fuel stored in said storage tank;

(iv) consolidating the inventory of said fueling station by correcting said delivered volumes with said delta.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described, by way of O 01/33386

-3- example only, with reference to the attached Figures, wherein:

Figure 1 shows a block diagram of a prior art reconciliation system for a service station;

Figure 2 shows a block diagram of an embodiment of an inventory control system in accordance with the present invention;

Figure 3 shows a flowchart of the operation of the inventory control system of Figure 2; and

Figure 4 shows a block diagram of another embodiment of an inventory control system in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a prior art reconciliation system 36. System 36 includes a tank level probe 40 which produces an output 44 which indicates the level of fuel in a storage tank 48. Output 44 can be processed, manually or automatically, to determine the volume of fuel in tank 48 by considering the known geometry of tank 48. Probe 40 can also provide temperature information so that temperature compensation can be performed for the volume of fuel in tank 48.

Tank 48 has one or more fuel delivery lines 52 which feed one or more fuel sales pumps 56. Each fuel sales pump 56 includes a flow meter 60 that provides an output 64 representing the volume of fuel which flows through pump 56. Outputs 64 are applied to an accumulator 68 which provides an output 72 representing the total volume of fuel which the pumps have delivered, i.e. - the sum of the volumes represented by outputs 64, in a selected time period. Reconciliation is then performed between the change in volume of fuel in storage tank 48 and the volume of fuel delivered by pumps 56 over some period of time, for example a two day period. In even the best circumstances, a reconciliation error of 1% to 2% of the total fuel delivered by pumps 56 may have to be accepted. This error can result from temperature compensation errors at pumps 56, inaccuracies in the geometry of storage tank 48 employed to determine the volume of fuel in tank 48, leakage from storage tank 48 or fuel delivery lines 52, drift and/or inaccuracies in flow meters 60, etc.

Figure 2 shows an inventory management system 100 in accordance with an embodiment of the present invention wherein like components to those shown in Figure 1 are indicated with like reference numerals. In system 100, the output 64 of each flow meter 60 is applied to its own accumulator 104. Accumulators 104 are connected to a consolidator 108, which is also connected to the output 44 of probe 40. Consolidator 108 can be any suitable device for operating on the data outputs from accumulators 104 and output 44 from probe 40 to consolidate the inventory. In one embodiment of the present invention, consolidator 108 is a ruggedized general purpose computer, such as an IBM PC compatible computer in an industrial enclosure, which executes a program, as described below, to consolidate inventory. In this embodiment, accumulators 104 can be memory or other data storage in the computer.

In another embodiment of the present invention, consolidator 108 is a general purpose computer which is located at a remote location from the service station and which receives the data outputs via a suitable communications network, such as the Internet, a dedicated telecommunications link or by physical transfer of a tape, disk or the like holding the necessary information. In this latter embodiment, a single consolidator 108 can be placed in a remote location and employed to consolidate inventory at a variety of service stations. This embodiment also allows inventory to be consolidated at a higher level, such as on an enterprise-wide basis.

In both embodiments, consolidator 108 operates to consolidate the changes in volume of fuel in a storage tank 48, as indicated by output 44, with the volumes of fuel sold, as indicated by the values of outputs 64 for each corresponding pump 56, as stored in accumulators 104. Consolidator 108 compares measured volumes of fuel sold from each operating pump 56 with the volume changes indicated by output 44 to determine differences between these volumes, which differences are stored, as described below, and used to produce a corrected consolidation 112. In the simplest case, a single pump (e.g. - pump 56a) is operating and consolidator

108 compares the decrease in volume in tank 48 with the volume of fuel sold, as indicated by accumulator 104 for that pump. Any discrepancies between the two volumes are noted and stored by consolidator 108 for that pump. In another case, two pumps (e.g. - pumps 56a and 56b) can be simultaneously operating and consolidator 108 will compare the total volume of fuel sold, as indicated by the two pumps, with the change in volume of the fuel in storage tank 48. Again, any discrepancies between the two volumes are noted and stored by consolidator 108 for those pumps. In another case, multiple pumps are operating (e.g. - pumps 56a, 56c and 56d) and consolidator 108 determines the total volume being sold, as indicated by the operating pumps, and compares this volume to the change in volume of fuel in storage tank 48. Again, any determined discrepancies are noted and stored by consolidator 108.

From the determined and stored discrepancies, consolidator 108 can make a variety of determinations. For example, consolidator 108 can have a stored discrepancy Δ_a for pump 56a O 01/33386

-5- which indicates that pump 56a is indicating that it has delivered 2% less fuel than has been removed from storage tank 48. Consolidator 108 can also have a stored discrepancy Δ_ac for pumps 56a and 56c which indicates that these two pumps indicate that they have delivered a total volume of 1% less fuel than has been removed from storage tank 48. By considering these two discrepancies, consolidator 108 can derive that pump 56c must be delivering a total volume of 1% more fuel than it indicates is has removed from storage tank 48. As will be apparent to those of skill in the art, by determining discrepancies for each possible combination of pumps operating, consolidator 108 can make accurate determinations of the errors in measurements by each pump and errors in measurements by probe 40. The errors determined for each pump 56 and for probe 40 can then be employed by consolidator 108 to provide a corrected reconciliation between the volume of fuel sold and the volume of fuel removed from the storage tank.

Figure 3 is a flowchart of the process employed by system 100. At step 200, a request is received and authorization for operation of a sales pump is performed. This request can result from a customer operating a self-serve pump or from a pump operator at a full serve station and the authorization enables the pump to commence a sale. When the request is received, the starting volume for storage tank 48 is determined, either from probe 40 or from previously stored volume information and is stored as V_st__ιn at step 204. At step 208, the volume sold from all of the operating pumps is recorded. The process loops at step 212, back to step 208, updating the recorded volume of fuel sold, until either a sale from an operating pump is complete or until a request to authorize another pump is received. If either test at step 212 is true, the process determines the change in the volume of fuel in storage tank 48, V,_c at step 216.

Next, at step 220, the process determines the delta ("Δ"), which is the difference between the change in volume of fuel in storage tank 48 and the recorded amount of fuel sold by the operating pumps 56. At step 224 this delta is stored, in a storage location corresponding to the pumps 56 which were operating, and V_start is determined again. At step 228 a determination is made as to whether any pumps 56 remain operating. If at least one pump 56 remains operating, a determination is made at step 232 as to whether a request to authorize a pump is pending. If such a request is pending, the pump is authorized at step 236 and the process proceeds to step 208 where the volume of fuel sold by the operating pumps 56 is recorded.

If, at step 228 it is determined that no pumps 56 remain operating, the process waits at step 200 to receive an authorization request or to service a pending request. „,,„_. PCT/CA O/ O 01/33386

-6- As an example of the process of Figure 3, assume that a request for authorization of pump 56a is received and the pump is authorized at step 200. W_aan is determined to be ten thousand litres at step 204 and pump 56a commences its sale and the volume of fuel sold is recorded at step 208 from the flow meter 60 in pump 56a. As pump 56a indicates that twenty-five litres of fuel have been sold, and the process is looping at step 212, a request for authorization of pump 56c is received. As a condition at step 212 is now true, the process proceeds to step-216 wherein V,_ is determined to be nine thousand, nine hundred and twenty-six litres.

At step 220, Δ. is determined to be minus one litre or -4% (i.e. (25-26)/25) and is stored in a storage location for pump 56a in consolidator 108 and _sαΛ is set to nine thousand, nine hundred and twenty-six litres. A determination is made at step 228 that at least one pump remains operating (in this example pump 56a is still operating) and the process proceeds to step 232 wherein it is determined that a pump, in this example pump 56c, requires authorization. Pump 56c is authorized at step 236 and the process proceeds to loop between steps 208 and 212. When the sale from pump 56a has completed (indicated for example by deactivating the control lever for the pump), one of the conditions at step 212 is true (e.g. - a sale has been completed) and the process proceeds to step 216 wherein V_tc is determined to be nine thousand, eight hundred and eighty-five litres.

In the period between authorization of pump 56c and completion of the sale of fuel from pump 56a, the recorded volume of fuel sold indicated by the respective flow meters 60 of pumps 56a and 56c, is determined to be forty-three litres. At step 220, Δ_ac is determined to be minus two litres or -4.9% (i.e. (41-43)/41) and is stored in a storage location for pumps 56a and 56c in consolidator 108 and V^ is set to nine thousand, eight hundred and eighty-five litres.

A determination is made at step 228 that at least one pump remains operating (pump 56c is still operating) and the process proceeds to step 232 wherein it is determined that no pump is awaiting authorization. The process thus proceeds to loop at steps 208 and 212 until the sale from pump 56c is completed. As a condition at step 212 is now true, the process proceeds to step 216 wherein V_lc is determined to be nine thousand, eight hundred, seventy-five and nine one hundredths litres. In the period between completion of the sale from pump 56a and completion of the sale of fuel from pump 56c, the recorded volume of fuel sold indicated by flow meter 60 of pump 56c, is ten litres.

At step 220, Δ_c is determined to be minus nine one-hundredths of a litre or - 0.09% (i.e. (9.91-10)/9.91) and is stored in a storage location for pump 56c in consolidator 108 and V , „ is set to nine thousand, eight hundred and seventy-five and nine one hundredths litres. A determination is made at step 228 that no pumps remain operating and the process proceeds to step 200 where a request for authorization is awaited.

As shown, at this point consolidator 108 has data for Δ_, Δ_a_ and Δ_c. In this example, with four pumps, consolidator 108 will eventually have data for each combination of pumps, i.e. - Δ_a, Δ_b, Δ_c, Δ_d, Δ_ab, Δ_ac, Δ_ad, Δ^, Δ_M, Δ^, Δ-_b-, Δ_abd, Δ_3C(1, Δ^ and Δ_abcd. It is however contemplated that in many cases, especially where more than four pumps are present, this will be more data than required for a desired degree of accuracy and that fewer deltas can be stored. For example, a sufficient set of deltas can be a delta for each individual pump and for each pair of pumps. Any additional information can be derived from such a set of deltas. Of course, other appropriate and sufficient sets of deltas will be apparent to those of skill in the art.

In any event, from a sufficient set of deltas stored therein, consolidator 108 can produce a corrected consolidation 112, representing to a high degree of accuracy the actual amount of fuel sold and fuel held in inventory. As will be apparent to those of skill in the art, each Δ for a pump, or combination of pumps, can be updated each time at least a portion of a sale involving the pump, or pumps, occurs. It can also be desired to weight changes to each Δ over some selected time period or sales volume to average the Δ's, thus avoiding spikes or swings in their values which may occur due to anomalous events.

It will also be apparent to those of skill in the art that by analyzing the values of Δ's in consolidator 108, leaks in tank 48 or supply lines 52 can be detected. Such leaks can be determined, for example, by examining the magnitude of the Δ's. In this example, one or more pumps 56 with large Δ's would be tested and recalibrated and the Δ's again determined. If large Δ's still occur, a leak or other problem must exist.

Figure 4 shows an inventory management system 300 in accordance with another embodiment of the present invention wherein like components to those shown in Figure 2 are indicated with like reference numerals. In this embodiment, consolidator 108 supplies an error correction signal 304 to each pump 56. As will be apparent to those of skill in the art, modem fuel sales pumps are microprocessor based systems wherein the output of the flow meter 60 in a pump 56 is converted from a pulse train or other output signal into a sales volume which is displayed to the purchaser. Once consolidator 108 has an appropriate Δ for a pump 56, a corresponding error correction signal 304 can be created by consolidator 108 and transmitted to the pump 56. For example, one hundred pulses from a flow meter 60 may nominally represent one litre of fuel sold. Consolidator 108 may determine that Δ_a, for pump 56a, is -10% (i.e. - pump 56a is delivering 10% less fuel than it otherwise indicates) and an error correction signal 304 can be applied to pump 56a such that now one hundred and ten pulses will represent one litre of fuel sold. As will be apparent to those of skill in the art, error correction signals 304 can be applied to pumps 56 at appropriate intervals, such as after each sale, or each day, etc.

Many modem fuel sales pumps are in fact multi-pump (allowing more than one user to purchase fuel at a time) and/or multi-product (allowing dispensing of different fuel blends, such as regular or premium fuels) units. It will be apparent to those of skill in the art that, as used herein, the term pump is intended to comprise any mechanism for dispensing and metering a fuel to a purchaser. Thus, a multi-pump unit is considered to be multiple pumps, each having its own Δ. A multi-product pump, if it has only a single flow meter 60 which is used to measure each product, can be considered to be a single pump and can have a single Δ which is used irrespective of the product dispensed. The above-described embodiments of the invention are intended to be examples of the present invention and alterations and modifications may be effected thereto, by those of skill in the art, without departing from the scope of the invention which is defined solely by the claims appended hereto.

Claims

„a, O 01/33386-9- We claim:

1. A fuel inventory management system comprising: a probe to determine the volume of fuel in a storage tank; at least two fuel sales pumps each operable to deliver a volume of fuel from said storage tank to a consumer and to measure said volume of fuel delivered; at least two accumulators, each accumulator operable to store data representing the measured delivered volume from each respective pump; a consolidator operable to determine differences between changes in volume indicated by said probe and said measured delivered volumes from said at least two accumulators for each of said at least two fuel sale pumps; and a storage device to store said determined differences, said consolidator operable to employ said stored determined differences to create a corrected consolidation between volume changes in said storage tank and fuel volumes delivered by said at least two fuel pumps.

2. A fuel inventory management system according to claim 1 wherein said storage device is integral with said consolidator.

3. A fuel inventory management system according to claim 1 wherein said consolidator is connected to said at least two accumulators and to said probe via a telecommunications network.

4. A fuel inventory management system according to claim 1 wherein said consolidator is further operable to produce an error correction signal, corresponding to said determined difference to each respective one of said at least two pumps, each of said at least two pumps employing said error correction signal to reduce said difference in a future delivery of fuel.

5. A method of managing fuel inventory at a fuel delivery station including a fuel storage tank and at least two fuel delivery pumps, comprising the steps of:

6. The method of claim 1 further comprising the step of, for each said at least one fuel pump, determining an error correction factor corresponding to said stored delta and applying said error correction factor to said respective pump to correct further determined volumes of fuel delivered by said pump.

7. The method of claim 5 wherein when two or more of said at least two fuel pumps are operating simultaneously, step (iii) is performed to determine and store a delta corresponding to said at least two simultaneously operating pumps and wherein when step (iv) is performed with said delta for each said at least one fuel pump and with each said delta corresponding to simultaneously operating pumps.