GB2101781A

GB2101781A - Commodity Meters

Info

Publication number: GB2101781A
Application number: GB08216245A
Authority: GB
Inventors: Roy Ernest White
Original assignee: UNITED GAS IND PLC
Current assignee: UNITED GAS IND PLC
Priority date: 1981-07-17
Filing date: 1982-06-03
Publication date: 1983-01-19
Also published as: GB2101781B

Abstract

A gas meter has electrical pulse producing means for indicating the amount of gas metered, which comprises reed switch S1, connected to output lines (13, 14). A resistance R1 is connected in parallel with S1, and a resistance R2 and disturbance switch S2 are connected in series with S1. The disturbance switch may be a tilt switch or an acceleration or trembler switch. Lines (13, 14) are connected to a logic device which determines from the circuit resistance whether or not the disturbance switch is operated. <IMAGE>

Description

SPECIFICATION Commodity meters This invention relates to commodity meters, for instance, gas, water or electricity meters, of the kind which have an electrical pulsed output related to the rate of use of the commodity.

The invention provides a commodity meter of the kind described having an electrical circuit providing a pulsed electrical output on an output line and electronic logic means operating on the output of said circuit to detect variation in a circuit parameter from a value or values corresponding to correct operation of said circuit and providing an alarm signal when such variation is detected.

The logic means may be built in to the meter with said circuit or may be in a remote position. In the remote position it may form part of a data logging device receiving the pulsed output from the meter and possibly from other meters, which acts as an interface between the meter and means for transmitting the reading of the meter to an outside station.

Specific embodiment of the invention are illustrated by the accompanying drawings, in which: Figure 1 is a circuit for use in a gas meter, Figure 2 is another circuit for use in a gas meter, and Figure 3 is yet another circuit for use in a gas meter.

A gas meter (not shown) has means for producing an electrical pulse for each predetermined unit of gas which is measured by the meter, so that the consumption of gas can be determined by a counting device receiving the pulses. The gas meter may have a cyclometer mechanical counting device providing a direct read-out of the consumption in addition to the electrical pulse output.

As shown in Fig. 1, the electrical pulse producing means for such a gas meter may be reed switch S, which is closed at intervals to produce an electrical pulse, by magnet means (not shown) moved by the meter mechanism.

External contacts (11, 12) on the gas meter provide connections to two output lines (13, 14) over which the pulses are transmitted to a remote date logging device (16). The data logging device may, for instance, provide said pulse counting device, so that the consumption can be determined directly from the device and may also providean interface for feeding signais related to the consumption to another reading station, for instance over telephone or electricity supply lines.

The circuit within the gas meter comprises a resistance R, in parallel with switch S" another resistance R2 in series with the S, R, arrangement, and a normally closed disturbance switch S2 in series with the whole circuit. The disturbance switch S2 may be a tilt switch, e.g. a mercury or gravity switch which is opened when the meter is tilted more than a predetermined angle from its normal position. Alternatively, it may be an acceleration detecting switch or trembler switch set to operate when more than normal disturbance of the meter occurs. It may alternatively be a reed switch located to detect the application of an external magnetic force to the switch S, which would tend to hold switch S, closed.

The disturbance switch may be a combination of two or more switches which each detect a different form of disturbance. Whichever form of disturbance switch is used, however, it is operated when there is an attempt to interfere with the normal operation of the meter or when some accident disturbs its normal operation.

The remote data logging device has internal circuits which are only indicated by a dotted line in the main, but has also a logic circuit (17) connected across the lines (13, 14). The logic circuit may be a microchip comparator, and detects the resistance state of the gas meter circuit by comparing the applied voltage with the resultant current flow. The logic circuit accepts as valid the normal resistance R, + R2 which occurs when the switch S, is open and the normal resistance R2 which occurs when the switch S, is closed. If the logic circuit detects other resistance states than this then it provides an alarm signal on line (18) into the circuit of the device. The alarm signal may be used to add a "false reading" indication to the gas meter reading output or to operate an alarm device.The resistance states indicating a false reading are a zero resistance due to a short circuit fault or to other interference or infinite resistance due to the external connection being cut or disconnected or to the disturbance switch S2 being opened.

By using the logic device it is possible to detect a number of possible faults and disturbance of the meter while still only using the two electrical lines connected to the meter over which the pulsed output is carried.

The circuit of Fig. 2 has similar items to those of Fig. 1 indicated by the same reference numerals. However, the disturbance switch S2 is here connected in parallel with the whole circuit, and is arranged to be normally open, closing on detecting disturbance.

The logic device (1 7) will therefore see a short circuit when this disturbance swith is operated.

The gas meter circuit of Fig. 3 also has similar items to those of Fig. 1, indicated by the same reference numerals. Here the two resistances R1 and R2 are placed in parallel with the changeover switch S, so that the two valid resistance states of the circuit are Ri or R2 depending on the state of switch S1.

1. A commodity meter of the kind de

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Commodity meters This invention relates to commodity meters, for instance, gas, water or electricity meters, of the kind which have an electrical pulsed output related to the rate of use of the commodity. The invention provides a commodity meter of the kind described having an electrical circuit providing a pulsed electrical output on an output line and electronic logic means operating on the output of said circuit to detect variation in a circuit parameter from a value or values corresponding to correct operation of said circuit and providing an alarm signal when such variation is detected. The logic means may be built in to the meter with said circuit or may be in a remote position. In the remote position it may form part of a data logging device receiving the pulsed output from the meter and possibly from other meters, which acts as an interface between the meter and means for transmitting the reading of the meter to an outside station. Specific embodiment of the invention are illustrated by the accompanying drawings, in which: Figure 1 is a circuit for use in a gas meter, Figure 2 is another circuit for use in a gas meter, and Figure 3 is yet another circuit for use in a gas meter. A gas meter (not shown) has means for producing an electrical pulse for each predetermined unit of gas which is measured by the meter, so that the consumption of gas can be determined by a counting device receiving the pulses. The gas meter may have a cyclometer mechanical counting device providing a direct read-out of the consumption in addition to the electrical pulse output. As shown in Fig. 1, the electrical pulse producing means for such a gas meter may be reed switch S, which is closed at intervals to produce an electrical pulse, by magnet means (not shown) moved by the meter mechanism. External contacts (11, 12) on the gas meter provide connections to two output lines (13, 14) over which the pulses are transmitted to a remote date logging device (16). The data logging device may, for instance, provide said pulse counting device, so that the consumption can be determined directly from the device and may also providean interface for feeding signais related to the consumption to another reading station, for instance over telephone or electricity supply lines. The circuit within the gas meter comprises a resistance R, in parallel with switch S" another resistance R2 in series with the S, R, arrangement, and a normally closed disturbance switch S2 in series with the whole circuit. The disturbance switch S2 may be a tilt switch, e.g. a mercury or gravity switch which is opened when the meter is tilted more than a predetermined angle from its normal position. Alternatively, it may be an acceleration detecting switch or trembler switch set to operate when more than normal disturbance of the meter occurs. It may alternatively be a reed switch located to detect the application of an external magnetic force to the switch S, which would tend to hold switch S, closed. The disturbance switch may be a combination of two or more switches which each detect a different form of disturbance. Whichever form of disturbance switch is used, however, it is operated when there is an attempt to interfere with the normal operation of the meter or when some accident disturbs its normal operation. The remote data logging device has internal circuits which are only indicated by a dotted line in the main, but has also a logic circuit (17) connected across the lines (13, 14). The logic circuit may be a microchip comparator, and detects the resistance state of the gas meter circuit by comparing the applied voltage with the resultant current flow. The logic circuit accepts as valid the normal resistance R, + R2 which occurs when the switch S, is open and the normal resistance R2 which occurs when the switch S, is closed. If the logic circuit detects other resistance states than this then it provides an alarm signal on line (18) into the circuit of the device. The alarm signal may be used to add a "false reading" indication to the gas meter reading output or to operate an alarm device.The resistance states indicating a false reading are a zero resistance due to a short circuit fault or to other interference or infinite resistance due to the external connection being cut or disconnected or to the disturbance switch S2 being opened. By using the logic device it is possible to detect a number of possible faults and disturbance of the meter while still only using the two electrical lines connected to the meter over which the pulsed output is carried. The circuit of Fig. 2 has similar items to those of Fig. 1 indicated by the same reference numerals. However, the disturbance switch S2 is here connected in parallel with the whole circuit, and is arranged to be normally open, closing on detecting disturbance. The logic device (1 7) will therefore see a short circuit when this disturbance swith is operated. The gas meter circuit of Fig. 3 also has similar items to those of Fig. 1, indicated by the same reference numerals. Here the two resistances R1 and R2 are placed in parallel with the changeover switch S, so that the two valid resistance states of the circuit are Ri or R2 depending on the state of switch S1. CLAIMS

1. A commodity meter of the kind de scribed having an electrical circuit providing a pulsed electrical output on an output line and electronic logic means operating on the output of said circuit to detect variation in a circuit parameter from a value or values correspond ing to correct operation of said circuit and providing an alarm signal when such variation is detected.

2. A meter as claimed in claim 1, wherein said electrical circuit includes disturbance switch means operable on the occurence of a disturbance to change said circuit parameter.

3. A meter as claimed in claim 2, wherein said disturbance switch means is a tilt switch or an acceleration switch or a trembler switch or a reed switch or any combination of such switches.

4. A meter as claimed in claim 2 or claim 3, wherein said electrical circuit includes one or more resistances and said switch means is connected so that on operation it puts said resistance or resistances in or out of circuit so that said logic circuit may detect a resistance change, said resistance comprising said circuit parameter.

5. A meter as claimed in claim 4, wherein said electrical circuit comprises a pulsing switch, a resistance in parallel with said pulsing switch, a resistance in series with said parallel combination, the disturbance switch being connected either in parallel or series with the whole circuit, said meter also comprising means for operating said pulsing switch at intervals related to the rate of use of the commodity.

6. A meter as claimed in claim 4, wherein said pulsing switch is a changeover switch alternating between two different resistances which are thereby connected in circuit in turn.

7. A meter as claimed in any of claims 1 to 6, wherein said electronic logic means is a comparator which detects said parameter and compares it with programmed acceptable values of said parameter.

8. A meter as claimed in claim 7, wherein said comparator is a microchip circuit.

9. A meter as claimed in claim 7 or claim 8, combined with a data logging device which houses said logic means and also has alarm means operated when disturbance is detected.

10. A meter as claimed in claim 9, wherein said data logging device also houses a pulse counting device connected to count pulses from said meter output line.

11. A meter as claimed in claim 10, wherein said data logging device also houses an interface for feeding signals representing the commodity use to another reading station.

1 2. A commodity meter substantially as described hereinbefore with reference to Fig.

1 or Fig. 2 or Fig. 3 of the accompanying drawings.

1 3. A meter as claimed in any of claims 1 to 1 2 adapted to measure gas usage.