GB2100036A - Measuring the amount of a supplied commodity - Google Patents

Abstract

A microprocessor 2 receives on an input channel 4 electrical pulses each representing supply of a predetermined amount of a commodity such as electricity, water, gas, or liquid fuel the supply of which is observed by a transducer arrangement 60. The microprocessor counts the pulses and the aggregate total of the amount of the commodity supplied can be digitally displayed on a visual display 12 and/or a print-out thereof provided by a printer 20. Also the microprocessor can calculate the cost of the amount supplied and that cost is shown by digital display and/or by print-out. If the commodity is A.C. electrical energy the transducer arrangement can be a Hall effect device 60 giving a continuous voltage signal which is a function of the volt-amperes taken by a load circuit. That voltage signal is filtered at 64 to remove the reactive power component and the remainder of the voltage signal relating to the real power taken by the load is converted by voltage to frequency converter 56 to the pulse signal. If the commodity is liquid or gas the voltage signal can be derived by an ultrasonic or infra-red Doppler shift device. <IMAGE>

Description

SPECIFICATION Method and apparatus to measure the amount of a supplied commodity This invention concerns a method of measuring the amount of a commodity supplied, and also concerns apparatus for measuring the amount.

The invention further concerns a method of measuring the incurred cost of a supplied commodity, and also concerns apparatus for measuring that cost.

The term "commodity" used herein is intended to mean anything of value for which a charge may be rendered in respect of the supply. For example the commodity may be supplied electrical energy or a supplied fluid such as a gas or liquid for example, water, liquid fuel, for example petrol, diesel oil or fuel oil, of fuel gas for example from the mains.

According to a first aspect of the invention a method of measuring an amount of a commodity supplied comprises observing the supply and producing a pulse signal in which each pulse represents supply of a predetermined amount of the commodity, and counting the pulses.

According to a second aspect of the invention a method of measuring an incurred monetary cost of a supplied commodity comprises measuring the amount of the supplied commodity as in the first aspect of the invention, and using the count and a monetary charge value of a pre-determined quantity of the commodity in a computation to derive the cost of the supplied amount.

According to a third aspect of the invention an apparatus for measuring the amount of a commodity supplied comprises observing means arranged to observe the supply of the commodity and produce a pulse signal in which each pulse represents the supply of a predetermined amount of the commodity, and counting means to count the pulses.

According to a fourth aspect of the invention an apparatus for measuring an incurred monetary cost of a supplied commodity comprises apparatus for measuring the amount of the commodity supplied as in the third aspect of the invention and computing means adapted to be supplied with data defining a monetary charge value of a pre-determined quantity of the commodity and to use the monetary charge value and the count to compute the cost of the supplied amount.

The invention will now be further described by way of example with reference to the accompanying drawings in which: Figure 1 diagrammatically shows electrical apparatus in accordance with the third and/orfourth aspect of the invention capable of performing the first and/or second aspects of the invention; Figure 2 diagrammatically shows a variation of the apparatus of Figure 1; Figure 3 diagrammatically shows a further variation of the apparatus in Figure 1; Figure 4 diagrammatically shows transducer means to observe flow of fluid along a conduit; Figure 5 diagrammatically shows Hall effect means to observe A.C. electrical power supplied; Figure 6 diagrammatically shows a pair of Hall effect means of the kind in Figure 5, to observe A.C.

three-phase power supplied using a three conductor system; Figure 7 diagrammatically shows three Hall effect means of the kind in Figure 5, to observe A.C.

three-phase power supplied using a four conductor system.

In the drawings and following description like references refer to like or similar parts.

With reference to Figure 1, the apparatus comprises a microprocessor 2 having an input channel 4. Manual entry means 6, for example, a keyboard, is provided whereby, via a signal encoder 8, data and instructions can be supplied to a microprocessor 2 and interogations applied thereto. Information, conveyed by signals from microprocessor 2, via decoder 10, can be displayed visually on digital visual display means 12.

The signals entering microprocessor 2 on channel 4 are electrical pulse signals in which the occurrence of each pulse represents the supply of a pre-determined quantity of a commodity. For example the signal can be a square wave pulse signal in which the frequency is a function of the rate of supply of the commodity and the occurence of each pulse indicates the supply of a pre-determined amount of the commodity since the occurrence of the immediately preceding pulse.

Counting means 14 in the microprocessor counts the pulses. The microprocessor is programmed to process the count to derive the amount of the commodity supplied since a known start of measuring the supply. Then either automatically or in response to an instruction by the key-board the amount of the commodity supplied since that start is displayed digitally on the display 12.

In addition or as an alternative the microprocessor 2 can operate on the count to derive the cost of the supplied commodity since the known start time and this cost may be automatically displayed by the display means 12 or in reponse to a demand from the keyboard.

In both instances the digital numerical value displayed is updated automatically in accordance with the processing of the count.

The microprocessor can include clock means 16 so that either automatically or on demand by the keyboard the display means 12 can show the time and/or the date when the microprocessor includes a date function in combination with the clock means.

If desired the microprocessor can be programed to automatically provide signals to the display means 12 whereby the digital display charges function automatically to display for predetermined periods each for example of 5 seconds, in cyclical succession the time, the date and the growing cost of the commodity consumed.

The date and time can be initially inserted and subsequently altered by data input by keyboard 6.

The keyboard can also be arranged to insert in the microprocessor data defining the charge per unit of the supplied commodity. The pricing system may comprise a number of tiers in which the charge per unit of supplied commodity changes after a pre-determined amount has been supplied and/or changes depending on the time of day of the supply. In addition keyboard 6 can be used to insert data relating to any fixed or standing charges automatically incurred. The microprocessor can be programmed so that on instruction from the keyboard 6 the cost displayed on display means 12 can include the standing charge component.

If desired the microprocessor 2 can be connected to a computer 18, for example a main frame computer, which may be operated by the person or utility providing the commodity. This computer can signal the microprocessor and update its charging data in accordance with any changes in the charging structure. Also the microprocessor can send data to computer 18 relating to the amount of commodity consumed and/or cost of the consumed commodity whereby the computer can record these details and operate to provide a communication to the consumer of a demand for payment, for example by a conventional bill or by sending a signal to microprocessor 2 causing the demand to be displayed on the display 12 or be printed as a bill by printer means 20 at the consumer's premises.This printed bill may be dated and include the time at which it was printed as well as giving the amount of commodity used and the charge.

If the commodity is electrical energy data transmission between microprocessor and computer 18 can be by the signals on the electrical mains cable.

The microprocessor 2 can be programmed to cause printer means 20 to give a print out, on demand by the keyboard of any of the data which the display means 12 can show.

The microprocessor can be programmed so that rate of commodity consumption can be represented by display means 12 on demand from the keyboard 6. The rate of consumption number may represent the rate of consumption per second and derived by counting the number of pulses accruing in a unit of time. This rate of consumption displayed may be updated every second so that from one second to another it is apparent if the rate is varying. By displaying the rate of consumption of electricity, for example in joules per second (watts), one can observe how much power any particular electrical appliance or machine is using.

Microprocessor 2 may also be programmed so that on a demand inserted from keyboard 6 the display means 12 will show how long at the present rate (or any other rate inserted by the keyboard) of consumption it will take to incur a pre-determined monetary charge for which data has been inserted by the keyboard.

Thus it is possible for example when the commodity is electrical power to predict, for a certain monetary sum how long an electrical apparatus may be operated until that sum is used up.

The microprocessor can be programmed to respond to signals from a coil or monetary token detection means 22 so as to allow supply of the commodity up to the monetary value of coins or token inserted in the detection means 22. When that monetary value is used up the microprocessor initiates operation of cut-off means 24to initiate interruption of the commodity supply.

The microprocessor can be programmed to respond to signals from a data reading means 26 arranged to read data (for example representative of a certain pre-paid monetary sum) provided on a data support. In response to the signal from the reading means 26 the microprocessor 2 allows supply of the commodity up to the monetary value represented by the data on the support. When that value is used up, interruption of the supply is initiated. The reading means may accept the data support to prevent its unauthorized re-use. Or the data may be in a magnetic or other form which is obliterated or removed from the support, for example a card, by the reading means 26 after the data has been read.

In the event of a consumer incurring an undesirably high debt, or incurs a charge which attains the value of his predetermined credit limit or uses up a previously paid sum allocated to his credit, the microprocessor 2 either in response to its own computations or in response to signals from computer 18 can initiate operations of shut-off means 24 to interupt supply of the commodity. Before operating the shut-off means 24, signal means 28 may be first operated on a pre-determined charge being incurred to signal to the consumer that his debt should be paid or a further sum paid to increase the amount to his credit.

In the event of a consumer wishing to pay the cost he has incurred, he may use the key board 6 to signal computer 18, (via microprocessor 2) whereby his instruction is transmitted from computer 18 to a computer 30 of the consumer's bank which makes the payment and signals computer 18 accordingly.

The microprocessor 2 can be programmed to operate shut-off means 24 automatically to interupt supply of the commodity or reduce the rate of supp]y in the event of the consumer's demand exceeding a predetermined rate or in the event of the monetary value, amount or rate used at a particular time of day exceeding a predetermined value.

The apparatus may be provided with an auxilliary supply of electricity from batteries coming automatically into operation in the event of failure or other interruption of the normal supply powering the apparatus. This auxilliarysupply ensures vital data is retained in memories of the microprocessor.

However the memories of the microprocessor may be of the non-volatile type, in which case the need for an auxiliary supply is not as critical.

In the arrangement shown in Figures 2 and 4 the supply of gas or liquid commodity along the conduit 32 is observed by transducer means 50 providing on channel 52 a continuous D.C. output voltage having a value which is a function of the velocity of the fluid along the conduit. Since the conduit is of constant and known cross-section the voltage on channel 52 is a function of the amount of commodity supplied in unit time.

Transducer means 50 is preferably located wholly externally of conduit 32 so as not to intrude into the fluid or conduit.

The transducer means 50 is of known type in which an electrical frequency signal on input 54 causes the emission through the fluid of infra-red or ultrasonic signals which when the fluid is moving in conduit 32 change frequency due to the Doppler effect. Receiving means in the transducer means receives the Doppler shifted frequency which is compared with the emission frequency and the difference between the emitted received frequencies is obtained. This difference is proportional to the fluid velocity and the voltage output signal which is proportional to the Doppler shift is produced.

Amplifier 54 amplifies the signal from channel 52 and the amplified output is fed to a voltage to frequency converter means 56 giving an output pulse signal on channel 4. The frequency of this pulse signal is a function of the rate of supply of the commodity and the occurrence of each pulse signifies the supply of a predetermined amount of the commodity since the immediately preceding pulse. The pulses may be of substantially the same width and the pulse signal may be a square wave signal.

With reference to apparatus in Figure 3 transducer means 60 is arranged to observe or measure the apparent power to volt-amperes of a load powered by A.C. from, for example, the mains. The transducer means given on channel 62 a continuous output voltage of a value which at any instant is a function of voltamperes or apparent power Pa.

VI Pa=-2 | [Cos 0 - Cos (2wt + p)], where V is the instantaneous voltage across the load, I is the instantaneous current through the load, 0 is the power factor, w is the A.C. frequency, and t is time The component VI Cos (2wt + ) 2 represents the reactive power which does no work on the load and accordingly should not be included in the measurement of the amount of energy taken by the load or in the cost of that energy. Impressed on the voltage signal on channel 62 is a frequency component which is a function of the reactive power.Therefore the signal on channel 62 is subjected to filter means 64 to remove or substantially remove the reactive power frequency component so that the continuous voltage signal output from the filter means is simply at any instant a function of the real power P of the load, where VI P=-2 Cos Thus even if the A.C. applied to the load is non-sinusoidal the real power is still accurately measured.

The voltage output from filter 64 is amplified by amplifier 52 and then converted to the pulse signal by converter 56. The occurrence of each output pulse represents the consumption by the load of a predetermined number of joules since the occurrence of the immediately preceding pulse.

The apparatus is arranged to measure the supply of a commodity upto a maximum amount A. Where a is any amount of the commodity upto A, the frequency b of the pulse signal emitted by converter 56 is in accordance with the equation a = k x b, where k is a predetermined constant. Therefore when a has maximum value A, b has maximum value B Hz and each pulse from converter 56 represents the numerical value k = A/B units of the amount of the commodity.

The cost of a unit U of the commodity is C. Accordingly the cost increment C is incurred each time U x B/A pulses have been counted.

If one wishes to increase the aggregate total of the cost of the commodity supplied by a fraction f of the cost C, the fractional charge increment F x C is incurred each time the pulse count attains the number f x U x B/A.

Since each pulse represents an amount of A/B of supplied commodity, the amount U of the commodity has been supplied each time the pulse count attains a value U x B/A.

If one wishes to increase the aggregate total of the amount of commodity supplied by a fraction F of the unit U, the aggregate total amount increases by the value F x U each time the pulse count attains the number F x U x B/A.

Starting with apparatus measuring the supply of the commodity from time zero the pulses from the converter 56 are counted in counter 70 in the microprocessor 2. At the end of a predetermined time frame, of for example one second, measured in pulses from the clock means 16, the content of the counter is transferred to a memory 72 and the counter counts in further pulses over the next time frame and when that frame expires transfers its count to memory 72 and commences counting again. Each time the content of memory 72 equals or exceeds the number f x U x B/A that number is substracted from the number in the memory and any remainder is left in that memory and the content of memory 73 increases by one charge increment f x C.When F charge increments F x C have arrived in memory 73 that memory is emptied and the aggregate monetary charge stored in memory 74 is increased by the charge amount C. As or when desired, a digital representation of the content of memory 74 is displayed by the display means 12 and/or printed out by printing means 20.

If it is predetermined that F = f, then each time the number in memory 72 equals or exceeds f x U x B/A an increment F x U is added to memory 75 storing the aggregate amount of the supplied commodity which can be digitally displayed as and when desired on display means 12. If the time frame is one second then the content of the counter 70 at the end of each time frame represents the rate of supply of commodity per second and the microprocessor can also convert the count into rate of supply per second data (for example watts) for digital display by display means 12 in response to demand from keyboard 6.

In a particular example relating to supply of A.C. power the apparatus can be arranged so that A = 20 Kw = 2 x 104joules per second at which frequency B from converter 56 is 1 x 104Hz. Accordingly each pulse counted represents a consumption of 2 joules of electrical energy since the immediately preceding pulse. f and F can both equal 0.01. U can be 36 x 105 joules or 1 kilo-watt-hour (Kwh) and C the cost of one Kwh.

fx U x B/Athusequals 18 x 103. Accordingly each timethe content of memory 72 reaches 18 x 103, the aggregate cost of supply in memory 73 increases by 0.01 C and the aggregate amount of the supply in memory 75 increases by 0.01 Kwh.

It will be appreciated from the above that since the apparatus can display the amount of commodity consumed, when that commodity is electrical energy, the apparatus can function as a kilo-watt-hour meter and can if desired, give a continuous, or normally continuos digital display of the amount in kilo-watt-hours of electrical energy consumed by a particular circuit system observed by the transducer means.

The transducer means 60 measuring the apparent A.C. power taken at any instant by a load is a Hall effect device shown in more detail in Figure 5 in which mains A.C. supply 70 powers a load 72 via lines 74 and 76.

The Hall effect device is shown at 78 and comprises semi-conductor 80 forming part of a tube 82 of which the remainder is of magnetically permeable material, for example ll-metal,toconcentratea magnetic flux path through the semi-conductor. Electric line 76 passes through tube 82. When electric current I flows through load 72 via line 76 a resultant magnetic field B is applied by tube 82 to semi-conductor 80. A transformer 84 has a primary winding 86 across load 72 and a secondary winding 88 applying current i generated therein, to semi-conductor 80 via lines 88 and 90. The current through the semi-conductor 80 is therefore a function of voltage V across the load 72.Output voltage Von channel 62 of the Hall effect device is a function of B x and thus a function of the volt-amperes or apparent power taken by circuit 70, 72, 74,76 namely the aforesaid VI 2 [Cos- Cos(2wtf PJ)I Figure 6 shows a three-phase AC supply powering loads 72 using three live lines 100, 102, and 104 in which two Hall effect transducer devices 60 are used to observe the apparent power.

Figure 7 shows how three Hall effect transducer devices 60 can be used to observe the apparent power when the three phase AC supply uses three lines 100, 102 and 104 and a neutral line 106.

Each of the output channels 62 from the transducers 60 includes filter means 64 to extract the reactive component from the voltage signal on each channel before the signals are added using an operational summing amplifier arrangement 54' giving an amplified and continuous D.C. voltage output signal to the voltage to frequency converter 56.

The transducer means 50 and 60 can be constructed for ready dismantling and re-assembly so it may be used at any desired location provided long enough channels or leads 52 and 62 are provided to connect the transducer means to the microprocessor 2.

The microprocessor 2 can also be programmed so that during any overall time period over which the processor is computing the amount and/or cost of the commodity supplied, it can also on instruction from keyboard 6 compute the amount and/or cost of the commodity supplied during a shorter time (within the overall period) for visual display and/or printout of that data relating to the shorter time.

The electronic constituents of the microprocessor may be provided on a single chip.

Claims (28)

1. A method of measuring an amount of a commodity supplied comprising observing the supply and producing a pulse signal in which each pulse represents supply of a predetermined amount of the commodity, and counting the pulses.

2. A method of measuring an incurred monetary cost of a supplied commodity comprising measuring the amount as claimed in claim 1, and using the count and a monetary charge value of a predetermined quantity in computation to derive the cost of the supplied amount.

3. A method as claimed in claim 1, in which the count of the pulses is processed to produce a visual digital display of the amount of commodity supplied and/or a printed record of the amount.

4. A method as claimed in claim 3, in which the commodity is electrical energy.

5. A method as claimed in claim 4 in which the or a said visual digital display is in kilo-watt-hours.

6. A method as claimed in claim 2, in which derived cost data of the supplied amount is processed to produce a visual digital display and/or printed record of the cost of the supplied commodity.

7. Apparatus to measure the amount of a commodity supplied comprising means arranged to observe the supply of the commodity and produce a pulse signal in which each pulse represents the supply of a predetermined amount of the commodity, and computing means provided with counting means to count the pulses.

8. Apparatus to measure an incurred monetary cost of a supplied commodity comprising apparatus measuring the amount of the commodity consumed as claimed in claim 7, and the computing means being adapted to be supplied with data defining a monetary charge value of a pre-determined quantity of the commodity and to use the monetary charge value and the count to compute the cost of the supplied amount.

9. Apparatus as claimed in claim 7 or claim 8, in which an arrangement comprising transducer means observes the supply of the commodity and produces a second signal which is a function of the amount of the commodity supplied, and conversion means to convert said second signal to said pulse signal.

10. Apparatus as claimed in claim 9, in which the second signal is a continuous voltage signal and the conversion means is voltage-to-frequency converter means.

11. Apparatus as claimed in claim 9 or claim 10, in which the apparatus is to measure the amount and/or cost of supplied fluid, and the transducer means is mounted on a conduit carrying said fluid.

12. Apparatus as claimed in claim 9 or claim 10, in which the apparatus is to measure the amount and/or cost of supplied electrical energy.

13. Apparatus as claimed in claim 12, in which the transducer means is arranged to give a continuous output voltage signal which is a function of observed power taken by an electrical load circuit system.

14. Apparatus as claimed in claim 13 in which the electrical energy is provided by an A.C. supply.

15. Apparatus as claimed in claims 10 and 14, in which the output voltage signal is a function of the volt-amperes observed in the load circuit system, filter means is provided to substantially filter a reactive power component from said output signal before the signal is fed as an input to said voltage-to-frequency conversion means.

16. Apparatus as claimed in claim 15, in which the transducer means comprises a Hall effect device.

17. Apparatus as claimed in any one of claims 7 to 16, in which the computing means comprises a microprocessor.

18. Apparatus as claimed in any one of claims 7 to 17, in which visual display means is provided to digitally display one or more measurements made by the apparatus.

19. Apparatus as claimed in claim 8 and claim 18 in which the visual display means can display the time, date and incurred cost automatically in cyclical succession.

20. Apparatus as claimed in claim 18 in which the digital display means can display rate of supply of the commodity.

21. Apparatus as claimed in any one of claims 7 to 20, in which printer means is provided to provide print-out of information comprising one or more measurements made by the apparatus.

22. Apparatus as claimed in any one of claims 7 to 21 having manual entry means to provide the computing means with data and/or instruct and/or interogate the computing means.

23. Apparatus as claimed in any one of claims 7 to 22, in which the computing means is powered by a first electrical supply and a second electrical supply comprising battery means is provided to power the computing means in the even of failure of the first supply.

24. Apparatus as claimed in any one of claims 7 to 23, in which the computing means comprises at least one non-volatile memory.

25. Apparatus as claimed in any one of claims 7 to 24, in which the computing means is connected to second computing means in a manner admitting transmission of data between them.

26. Apparatus as claimed in claim 8, or in any one of claims 9 to 25 when appended to claim 8, provided with areas to accept pre-payment of the cost of the supplied commodity.

27. Apparatus as claimed in claim 8, or in any one of claims 9 to 26 when appended to claim 8, provided with means to cut off supply of the commodity.

28. Apparatus as claimed in any one of claims 7 to 27, serving as a kilo-watt-hour meter.