GB2068131A - Metering devices - Google Patents

Abstract

A device for registering the amount of electrical power supplied to a consumer, comprising inductive coupling means 10 for surrounding an electrical lead 11 by which electrical power is supplied to the consumer and arranged to provide a voltage indicative of the flow of current in said lead, means 14, 15, 16 for converting said voltage into a pulse train the pulse repetition frequency of which is directly proportional to the rate of electrical power supply in said lead, means for adding pulses of said train into a store, means 17 for receiving signals indicative of the count of said store and of the charge to be made in respect of one unit of the electrical current supplied and for providing an output signal indicative of the charge to be made for the electrical power supplied and means 22 for displaying said output signal. <IMAGE>

Description

SPECIFICATION Metering devices The invention relates to metering devices.

Certain services provided to a householder, for example gas, water and electricity (hereinafter referred to as products) are supplied to the consumer through an analogue metering device which measures, usually mechanically, the amount of the product passing therethrough to be supplied to the consumer (for example the device may measure water supplied in thousands of gallons, gas supplied in cubic feet and electricity supplied in kilowatt hours).

Meters at present in use provide a visual indication of the amount of the product supplied to the consumer, and are arranged to be read periodically by a servant of the company supplying the product to the consumer. After each periodic reading a charge is rendered by the company to the consumer on the basis of the indicated quantity of the product consumed.

It is possible but not easy for a consumer to determine, by looking at the display given by the company's metering devices the charge that will be made to him and it is therefore difficultforthe consumerto budget his use of a product being supplied.

The present invention aims to provide a device which will readily enable a consumer to see at any moment how much he will be charged for a product with which he has been supplied.

The present invention provides a device for measuring the quantity of a product supplied to a consumer and providing a display of the charge to be madetherefor.

The device preferably comprises first means for producing an electrical signal indicative of the quantity of a product supplied to a consumer, second means for receiving said signal and operative in response thereto to provide a further electrical signal indicative of the charge to be made to the consumer and third means for displaying said further signal.

Preferably the quantity of product consumed is measured electrically.

Said first means for providing a signal indicative of the quantity of product consumed preferably provides a pulsed signal the pulse repetition frequency of which is proportional to the rate at which the product is being supplied.

Pulses of the pulsed electrical signal indicative of the quantity of product supplied may be added to a store, the total of pulses held in the store being modified in accordance with a further signal indicative of the rate to be charged for each unit of the product consumed thereby to produce an output signal indicative of the charge to be made to the consumer in respect of the quantity of product supplied.

The output signal may be displayed, for example using a light-emitting diode or liquid crystal display.

Modifications of the described device provide an arrangement in which a signal indicative of a fixed charge, equivalent for example to a standing charge to be madeto a consumer, is initially read into the store as a base figure to which pulses of said pulsed signal are subsequently added.

A preferred arrangment of the invention provides means for registering the amount of electrical power supplied to a consumer said means comprising inductive coupling means for surrounding an electrical lead by which electrical power is supplied to a consumer and arranged to provide a voltage indicative of the flow of current along said lead, means for converting said voltage into a pulse train the pulse repetition frequency of which is directly proportional to the rate of electrical power supply along said lead, means for adding pulses of said train into a store, means for receiving signals indicative of the count of said store and of the charge to be made in respect of one unit of the electrical current supplied and for providing an output signal indicative of the charge to be made for the electrical power supplied and means for displaying said output signal.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows schematically a circuit diagram of a device for indicating the charge to be made for electrical power supplied to a consumer, and Figures 2 and 3 show, respectively, a perspective view of the front, and a rear view of the device of Figure 1.

The drawings show at 10 an inductive coupling arranged to surround a mains lead 11 carrying current, for example to an electrical supply company's metering unit, in a consumer's home. Coupling 10 is arranged to feed an induced voltage to one input of a D.C. differential amplifier 12 the other input of which is fed with a reference voltage from a reference voltage source 13 (not shown). The arrangement is powered by a battery, not shown.

The output of amplifier 12 is fed to a voltage-tofrequency converter 14 the output of which is in the form of a signal frequency modulated by an amount proportional to the current flowing in the lead 11 and therefore proportional to the power being supplied to the consumer.

The output of converter 14 is fed to a pulse shaped circuit 15 to provide a square pulse train at a pulse repetition frequency proportional to the rate at which current flows along lead 11. The output of the circuit 15 is fed to a divider circuit 16, arranged to provide an output signal in the form of a pulse train with a very low pulse repetition frequency. For example the divider 16 is preferably arranged to provide one output pulse per hour if the power being drawn along the feed 11 is one kilowatt (that is to say the consumer is drawing a current approximately equal to 4.2 amps). The output of divider 16 is fed to a chip 17 arranged to add pulses supplied from divider 16 into a store. The output from divider 16 may be fed to chip 17 via interfacing circuitry if necessary.

The signal held in store in the chip 17 is arranged to provide an output signal at a lead 19 indicative of the product of the sum of the pulses received from the divider 16 and a signal indicative of a figure set, in a unit 20, indicative of the cost per kilowatt hour of electricity supplied.

The output 19 of chip 17 therefore provides a signal indicative of the product of the sum of pulses supplied to it from the divider 16, and signal from the unit 20.

In the present example if the price per kilowatt hour of electricity supplied to a consumer is 2.65p the unit 20 will be arranged to provide a signal indi cative of this sum to the chip 17 and the output 19 of the unit 17 will carry a signal indicative of the pro duct of the number of pulses received by it from the divider 16 and the figure 2.65. Thatistosaythe signal at output 19 will be indicative of 265 after one pulse has been received by the circuit 17,265 after 100 pulses have been received, 530 after 200 pulses have been received and so on.

Output 19 of device 17 is coupled to a decoder21 which in turn drives a light-emitting diode display 22. Display 22 is arranged to show a consumer the total charge he may expect in respect of the electricity that has been supplied to him. Display 22 is actuable by a consumer by depressing a switch 23 The unit 20 is arranged to provide a sigrrat indicative of the cost per kilowatt-hour of electrical being supplied by the adjustment of thumb wheels, orthe like, such as are shown in Figure 3.

Chip 17 is arranged to respond to operation of a control switch 24to resetthe count in the storeto a base figure, for example when the meter provided by the electrical company has been read. A start circuit 25 is provided for the chip.

Figure 2 shows that a device embodying this invention comprises a box roughly 15mm by 10mum by Smm and having on one side a display 26 divided as shown to show units of currency, for example, pounds and pence.

One end of the device is provided with an aperture 27 through which the inductive coupling 10, in-the form of a clamp 28, extends. Clamp 28 may be per ated, by means not shown, to close (as shown in Figure 2) around the lead 11 carrying electrical power to the consumer.

Button 29 provided on the front panel of the device enabling the device to be started. Depression of button 29 device triggers circuit 25 or alternatively may feed into the chip 17 a signal indicative ofabase figure such as a standing charge which isto be charged to a consumer by the company supplying the product.

A second switch 30 is also provided enabling the pulse count of the store in chip 17 to baresetto a base figure when desired.

Figure 3 shows the back of the device as including a plurality ofthumb wheels 31 (in the example shown there are four thumb wheels)* enabling the rate per kilowatt hour of power supplied to a consumer to be read into the device, by adjusting the setting of the device 20 feeding a modifying signal to the chip 17 of the circuit of Figure 1.

As shown in the example of Figure 3 the thumb wheels 31 have been adjusted to give a cost per kilowatt hour of electricity, of 2.65p. They could of course be setto any other figure which is adopted by the electrical supply company, and enable adjust ment, for example to account for possible increase in the cost of electrical power supplied to a customer within one electrical supply company area orto enable the device to be moved between areas served by different electrical supply companies which sup ply electrical power at different rates.

Operation of the device described, by a consumer, is quite straightforward.

the consumer arranges that the clamp 28 sur rounds on of the leads, preferably a line lead, lead ing to or from the meter placed in his home bythe company supplying electrical power to him. Hethen adjusts the thumb wheels 31 on the rear of the device to show the rateatwhich poweristo be charged to him by the company, (in the example shown in lFigure32.65pperunit).

He then presses the start button 29 on the front of the device. Subsequent depression of button 32 gives the consumer a running total on display 26, of the charge to be made to him by the company supplying him with electricity.

It is envisaged that modifications to the above described arrangement may be provided for example the user may use the thumb wheels 31 on the back of the device to enter the standing charge to be made to him by the company' supplying him with electrical power. Upon depression of a button, for example button 30 on the frontofthe unit, this figure could then be read into the store in chip 17.

Adjustmentofthe thumb wheels on the back of the device to show the rate charged per unit by the company supplying him with electricity and the depression of the button 29 would then enable the consumer to know the total bill he is likely to receive from the company supplying him with power.

It might be advantageous to incorporate the device in a domestic consumer unit, commonly known as a fuse-box, so that the clamp 28 could be built in.

The above described arrangement may further be modified to be usable, for example, in measuring any other products supplied to a consumer. For example the inductivecoupling 10 may be replaced by a mechanical device driven to rotate at a predetermined rate by the passage passed it of a given amount of fluid, for example water or gas. The pulses produced buy the device measuring the flow rate offiflid may then be fed to the chip 17 in much the same way as has been described above to enable a consumer to know the cost ofsupply to him of such services as gas andlorwater.

A major advantage of the described arrangement is thatit enables aconsumerto see, at advance, the costtohim him of the, productwith which he has been supplied. In particular this arrangement enables a consumer to readily adjust the rate at which the meter gives an indication of his charge to be made to him take account of variations in the standing charge andlorrate per unit charge made to him bythecom- pany supplying him with the product.

Such devices are readily produced at low cost and have advantages for example in the case of multioccupied dwellings to enable a landlord to readily ascertain the correctcharge to be made to each of his tenants. At the same time the devices enable each tenant two know the charge they are to receive for the product consumed, from the landlord.

Claims (9)

1. A device for measuring the quantity of a pro duct supplied to a consumer and providing a display of the charge to be made therefor, comprising first means for producing an electrical signal indicative of the quantity of a product supplied to the consumer, second means for receiving said signal and operative in response thereto to provide a further electrical signal indicative of the charge to be made to the consumer and third means for displaying said further signal.

2. A device according to claim 1, wherein the quantity of product consumed is measured electrically.

3. A device according to claim 1 or claim 2, wherein the first means provides a pulsed signal, the pulse repetition frequency of which is proportional to the rate at which the product is being supplied.

4. A device according to claim 3, wherein pulses of the pulsed electrical signal are added to a store, the total of pulses held in the store being modified in accordance with a further signal indicative of the rate to be charged for each unit of the product consumed thereby to produce an output signal indicative of the charge to be made to the consumer.

5. A device according to claim 4, wherein the output signal is displayed using a light-emitting diode or liquid crystal display.

6. A device according to any one of claims 3 to 5, wherein a signal indicative of a fixed charge is initially read into the store as a base figure to which pulses of said pulsed signal are subsequently added.

7. A device for registering the amount of electrical power supplied to a consumer, comprising inductive coupling means for surrounding an electrical lead by which electrical power is supplied to the consumer and arranged to provide a voltage indicative of the flow of current in said lead, means for converting said voltage into a pulse train the pulse repetition frequency of which is directly proportional to the rate of electrical power supply in said lead, means for adding pulses of said train into a store, means for receiving signals indicative of the count of said store and of the charge to be made in respect of one unit of the electrical current supplied and for providing an output signal indicative of the charge to be made for the electrical power supplied and means for displaying said output signal.

8. A device according to any preceding claim, incorporated in a domestic consumer unit.

9. A device substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.