EP0354975A1

EP0354975A1 - Commodity meters

Info

Publication number: EP0354975A1
Application number: EP88307584A
Authority: EP
Inventors: Patrick Bass; Constantine Michaelides
Original assignee: Smith Meters Ltd
Current assignee: Smith Meters Ltd
Priority date: 1987-07-18
Filing date: 1988-08-16
Publication date: 1990-02-21
Anticipated expiration: 2008-08-16
Also published as: HK79191A; GB2207269B; EP0354975B1; GB8716987D0; GB8816236D0; GB2207269A

Abstract

Commodity meter (11) is adapted for prepayment by insertion of credit card (32) into a card reader and eraser unit (30). The unit sends a command signal over a multicore cable (21) to drive a motor (18) within the meter casing.

Motor (18) drives a cam (16) to a rotational orientation representing the amount of credit. Mechanical drive (17) from metering elements (not shown) drives cam (16) to reduce the amount of credit. At zero credit cam (16) holds a valve (14) closed, while in credit representing positions it is opened. The valve is connected in the flow line of the commodity through the meter.

Should cable (21) be severed, the mechanical drive continues to reduce the credit until the valve closes.

Description

This invention relates to commodity meters through which a flowing commodity is supplied, the meter measuring the volume of commodity for payment or other purposes.
Such meters have commonly been arranged as prepayment meters into which coins are inserted, thus freeing the meter to supply a specific volume of the commodity. Such meters are liable to attempts at theft of the money in them and efforts have been made to meet this problem by replacing the coins with tokens of negligible intrinsic value. However, meters using tokens are liable to attempts to avoid payment.
This invention provides a metering apparatus for a flowing commodity arranged to operate on a prepayment system, wherein metering elements are enclosed in a casing, a valve is located in the same casing connected in the flow path through the meter so as to control the supply of the commodity, and a separate token-operated device provides an electrical credit signal to credit storage means connected to control the valve.
The credit storage means may include cam means controlling the opening and closing of the valve, the orientation of the cam comprising a measure of the credit stored. The cam means may be driven by electrically-powered means to insert credit. The cam means may be driven by the operation of the metering elements to remove credit.
According to another arrangement, the credit storage means may comprise an electronic memory controlling electrically-powered means which opens and closes the valve. The memory receives data from the metering elements which progressively reduces the credit recorded in the memory until at zero credit the valve is caused to close.
By using an internal valve with an external token-operated device it is found that a higher degree of security can be achieved than at first appears. Attempts to interfere with the device simply stop further credit being inserted without causing the valve to stay open.
Preferably the commodity meter is a gas meter. The electrically-powered means may be a motor or other actuator such as a solenoid, or a stepping motor.
Two specific embodiments of the invention are shown in the accompanying drawings, in which:-

Figure 1 comprises a representation of a token-operated gas metering apparatus,
Figure 2 shows diagrammatically the operations of the apparatus of Figure 1,
Figure 3 shows diagrammatically the operations of another apparatus, and
Figure 4 is a three dimension representation of part of the apparatus of Figure 3.

A gas meter (11), in both embodiments, is of the kind comprising flexible diaphragms driven back-and-forth by flowing gas, which is of proven accuracy and reliability. The meter has a mechanical counter mechanism of conventional kind providing a read-out (12) of the measured volume of gas which has passed through the meter, and also has means for providing an electrical reproduction of the read-out, either as a series of electrical pulses or as a coded representation of the number. Suitable examples of such means are described in our patent applications numbered 2 187 010 and 2 187 011.
Referring now to Figures 1 and 2, there is located in a main gas flow path through the meter, an on/off valve (14), which may be a poppet valve operated by pivotting of a lever (19) against spring resistance by means of a rotatable cam (16). When open, the valve is held in that position by the cam (16). A drive pinion (17) connected to rotate the cam directly or indirectly is driven by the mechanical counter mechanism so that as gas is consumed the cam is rotated. At a position at which all the credit is used up, as described hereinafter, the cam reaches a release position at which valve (14) closes under the spring pressure. Spindle (15) driven by a DC motor (18) also rotates cam (16) through a clutch mechanism, in the sense that motor (18) advances the cam while the drive pinion (17) reverses it.
A card reader and eraser unit (30) is located at a position convenient to a user and may be remote from the gas meter (11). The unit has a slot (31) into which a gas card (32) may be manually inserted. The gas card carries a magnetic code relating to its face value (shown as £2), and the unit operates to read the code and send a corresponding command signal over a multicore cable (21) for a period of time related to the said face value. During this period of time, motor (18) operates to rotate the cam (16) through an angle related to the face value, and to open the valve (14). Subsequent use of gas mechanically drives pinion (17) to return the cam toward its initial position. Clearly, larger rotations of cam (16) require larger gas usage to return the cam to the initial position where the valve (14) closes. Thus the angular position of the cam acts as a mechanical credit store. The mechanism is normally adjusted so that the amount of gas used is valued at the face value of the card, but may be adjusted to provide a smaller quantity of gas so that bad debts may be recovered in stages.
When the unit (30) has read the card, it erases the magnetic code so that the card cannot be used again.
The read-out (12) is reproduced at (33) on the card reader unit (30) by means of the electrical signals described above, which are transferred on cable (21).
All of the electrical functions, as seen best in Figure 2, including the electrical reproduction of the read-out (12), are powered by a replaceable dry battery (34) mounted in the unit (30).
A mechanically driven indicator (35) in the meter is interconnected with the cam (16) so that an indication of the unused amount of prepaid gas is shown. This indication is also transferred to be shown on unit (30) at indicator (35′). Both indicators (33) and (35′) may be provided by a single display unit.
The magnetically coded gas cards (32) may be purchased at appropriate retail outlets, and discarded when used. Alternatively, the same card may be re-activated at the retail outlet on payment of the face value. Thus there is nothing to be collected from the meter, neither money nor token.
The apparatus described has a high degree of Inbuilt security against fraud. It will be noted in particular that if cable (21) is severed, the winding back operation through pinion (17) is not interrupted, because this is entirely mechanical, powered by the gas pressure. Thus the valve (14) will close when the prepaid gas is used up and all that will happen is that the user is unable to insert more credit into the meter. The valve (14) being mounted inside the meter has the same degree of security as the meter index. A further advantage is that there is no internally generated electrical supply in the meter, the battery (34) being used for all the electrical requirements, including the electrical coding of the meter reading. If desired, the electrical representation of the meter reading can be directed further afield, for instance to an official reading station or directly to a computer which checks the gas usage and compares it with records of the user's purchases of gas cards.
In the alternative apparatus shown in Figures 3 and 4, the gas meter (11) has a gas valve (14) internally fitted as described with reference to Figure 1. The valve (14) is driven to open position by a DC motor (40) mounted on the outer surface of the meter. A card reading and erasing unit (30) similar to that described in relation to Figure 1 is mounted in a position convenient for access. When a gas card is inserted into the unit, the face value is read and transferred to an electronic credit storage unit (41) which is also mounted inside the unit. When credit is thus established, a signal to motor (40) causes it to open valve (14). As the gas is used, the meter (11) produces electrical pulses which are sensed by the credit storage unit (41) and substracted from the credit stored. When the credit has returned to zero, another signal releases a solenoid (42) to close valve (14) as described hereinafter. In this arrangement, both the card reading unit (30) and the meter have their own replaceable dry batteries (34) and (34′).
Referring now to the detail of Figure 4, the DC motor (40) drives cam (44) through a gear train (45). A roller (46) Mounted on a pivoted cradle (47) runs on the cam so that cradle (47) rocks. A shaft (48) is secured at one end to a closure member (49) of the gas valve (14) within the meter and extends out through the wall of the meter (not shown) to extend freely through bearings in the cradle (47). A lever (50) is secured at one end to rotate with the shaft (48) and at the other end carries an armature (51) which co-operates with solenoid (42). As shown in full lines in the Figure, a valve closing spring (52) is urging the lever (50) upwards so as to rotate shaft (48) in the sense to maintain the gas valve (14) in the closed position. In order for the valve to be opened, armature (51) must take up the position shown in dotted lines. Solenoid (42) is of the 'self holding' type, incorporating a permanent magnet strong enough to hold the valve open, but also having means for producing a flux in opposition to the holding flux which thus cancels it and releases the armature (51).
When credit is established in storage unit (41) an electrical signal actuates motor (40). This drives cam (44), rocking cradle (47) first to raise solenoid (42) from the position shown In dotted lines until it contacts armature (51). The permanent magnet then carries the armature down as the solenoid returns to the position shown in dotted lines, thus opening the valve. The cam (44) rotates until homing microswitch (53) is operated, indicating that the cam has completed a full circle, at which point motor (40) ceases to operate. The valve then remains open until an electrical 'release' signal is received by the opposition flux circuit of the solenoid (42). This releases the armature (51) so that spring (52) can lift lever (50) and open the valve. On cessation of the release signal, the armature (51) is too far distant from the solenoid for the holding magnet to attract it against the spring force. Thus the valve can only be opened when cam (44) again rotates and lifts solenoid (42) into close proximity to the armature (51).
The 'release' signal is produced on the occurrence of several different situations. The main one is of course when the credit in storage unit (41) runs out, but it is also used for safety features. In the event of tampering with the gas meter, for instance tilting or cutting of the electrical connection wire (21), or tampering with the card reading and erasing unit (30), a 'release' signal is produced which causes the valve to close. It will be noted that the release will work even whilst credit has been added and the motor is opening the valve.
The battery (34′) may be a long life, high density primary cell or a rechargeable battery or a low leakage capacitor charged by external means.
Although a gas card with magnetic information is described above, it is within the invention to use other tokens for inserting credit. For instance, rechargeable tokens each incorporating a micro-processor which can be programmed to represent any credit sum desired may be used.
Both apparatus described can incorporate an emergency supply system in which the user is allowed a limited free supply on demand, payment for which is then deducted from the next credit input. In the Figure 1 embodiment this is provided by a button-operated circuit in the card reader (30), which provides one only free credit input to the motor (18) and then deducts the same credit from the next card inserted. In the Figure 3 embodiment, this is provided by a special memory section of the credit store (41) which provides one only free credit and then deducts this from the next input from the card reader (30).
In another apparatus (not shown) the valve (14) is driven to open and shut positions by the same DC motor under the control of the credit storage unit. The motor and credit storage unit are mounted within the meter casing.
Although the invention has been described in relation to gas meters, it may be used in any other kind of meter in which a flowing commodity is controlled by a valve.

Claims

1. A metering apparatus for a flowing commodity of the kind arranged to operate on a prepayment system, having metering elements enclosed in a casing and a valve means (14) located in the same casing in the flow path of the commodity so as to control the availability of the commodity, characterized by a separate, token-operated device (30) adapted to provide an electrical credit signal to credit storage means (16, 41), which credit storage means controls the opening and closing of the valve means (14).

2. A metering apparatus as claimed in claim 1, further characterized by said valve means (14) being arranged to close either immediately or when credit runs out on normal operation of said token-operated device (30) being interrupted.

3. A metering apparatus as claimed in claim 1 or claim 2, further characterized by said credit storage means (16) including cam means controlling the opening and closing of the valve means (14), the orientation of the cam means comprising the stored credit value, and also including electrical drive means (18) for the cam means operated by the said electrical credit signal.

4. A metering apparatus as claimed in claim 3, further characterized by mechanical drive means (17) from the metering elements to drive the said cam means (16) in the opposite sense to the electrical drive means (18), whereby the credit value stored is increased by the electrical drive means and decreased by the mechanical drive means as the commodity is used, the cam means closing the valve means (14) at an orientation representing zero credit value.

5. A metering apparatus as claimed in claim 4, further characterized by the cam means (16), electrical drive means (18) and mechanical drive means (17) being all mounted within the said casing.

6. A metering apparatus as claimed in claim 1 or claim 2, further characterized by the credit storage means comprising an electronic memory (41), and there being an electrical drive means (40, 42) for the valve means (14) operated by said electrical credit signal.

7. A metering apparatus as claimed in claim 6, further characterized by the metering elements being adapted to provide an electrical "commodity used" signal which is directed to the electronic memory (41) to reduce the stored credit value, the electronic memory controlling electrical signals which operate said electrical drive means (40, 42) to open the valve when there is positive credit and to close it when the credit value drops to zero.

8. A metering apparatus as claimed in claim 7, further characterized by said electrical drive means comprising an electric motor (40) and a self-holding solenoid (42), operation of the motor being in consequence of a positive credit signal from the electronic memory, said solenoid (42) having a "release" circuit which is adapted to be operated by a zero credit signal from the electronic memory, causing the solenoid to close the valve means.

9. A metering apparatus as claimed in claim 8, further characterized by said motor (40), in order to open the valve means, moving the said solenoid (42) in the sense to cause the solenoid to hold the valve means open, whereby when the said release circuit is energized the solenoid releases the valve means which then returns to a closed position.

10. A metering apparatus as claimed in claim 8 or claim 9, further characterized by means for sensing tampering or damage to the apparatus, which means is adapted to produce a "valve close" command signal having the same effect as the zero credit signal from the electronic memory.

11. A metering apparatus as claimed in claim 10, further characterized by said tamper sensing means being adapted to sense when the separate token-operated device (30) and/or an electrical connection between it and the casing is damaged.

12. A metering apparatus as claimed in any of claims 1 to 11, further characterized by said separate token-operated device being adapted to read credit information on a credit card, and to cancel that information on the credit card after accepting the credit value for insertion into the said credit storage means (16, 41).