GB2231668A

GB2231668A - Remote reading and cutoff system for domestic gas meters

Info

Publication number: GB2231668A
Application number: GB9010978A
Authority: GB
Inventors: Josep Picanyol Valls
Original assignee: PARA LA FABRICACION D Cia; Repsol Butano SA
Current assignee: PARA LA FABRICACION D Cia; Repsol Butano SA
Priority date: 1989-05-16
Filing date: 1990-05-16
Publication date: 1990-11-21
Also published as: FR2647209A1; ES2011576A6; IT1242052B; IT9020314A1; GB9010978D0; DE4015757A1; FR2647209B1; IT9020314A0

Description

--:;>:3 -1- C_ > REMOTE READING AND CUTOFF SYSTEM FOR DOMESTIC GAS METERS

The invention refers to a system for the remote reading and cutoff of domestic gas meters, based on a set of interconnected electronic, mechanical and electromechanical devices. The aim of this system is to enable the remote reading of a certain number of domestic gas meters, as well as to allow the remote opening or shutting off of stopcock valves connected in series with the meters.

The system proposed is based on an impulse emitting device linked to every meter, and on a gas electrovalve forming the subject of our co-pending U.K.

Patent Application No. (our ref 33451M). Both elements (impulse emitting device and electrovalve) are connected in series and electrically linked to a concentrating device, which will be placed at a location accessible to the gas utility company, which is where the system is driven from.

It also comprises a portable terminal optically linked to said concentrator, which terminal provides access to all the information contained (values of the meter counters, system parameters, status of the alarms, etc.); such that the opening or shutoff of any stopcock valve can be controlled by means of said terminal.

From the above, it may be clearly deduced that the scope of application of the system can be made extensive to all the domestic distribution networks of combustible gases.

Prior to the relevant description of the system, and of its operation, a number of characteristics defining the present technical state of this field will be mentioned. In this respect, it is a fact that gas

2 utility companies are trying to solve the three major problems given below:

1._ Reading of consumption levels: There is an attempt to achieve systems which enable faster and more reliable reading procedures and which allow the automation of the data processing, which implies a reduction in cost (less errors, shorter time lapse between reading and invoicing, etc.) 2.Supply cutoff: Utility companies are often faced with the prospect of having to cut off the supply of gas to a household, due to various reasons (safety, unauthorized handling of installation by the user, failure to pay the bills).

3.- Access to the user's household: The development of a system enabling the above stated procedures without having to travel to the user's household is an extremely attractive feature, both in order to avoid disturbing said user, and so as not to encounter such legal problems as might arise when the utility company must perform the above stated procedures by entering the user's household.

The equipments currently in existence are quite varied, and present one or several of these shortcomings. Therefore, equipments and systems may be found which improve the reading of meters, making it faster, systems which allow remote cutoff of the gas supply without having to enter the user's household, or systems which provide a solution to both matters without optimizing either of them.

The systems developed on a world scale to try to solve these three problems; i.e. to improve the reading of meters and to cut off the supply, can be summarized t:

3 into three groups, although each of them includes several ways of achieving its aim, and these three major groups are:

a) Systems which improve the reading of meters; b) Remote supply cutoff systems; and, c) Intelligent cutoff systems.

As regards the first group (systems which improve the reading of meters), it may be summarized as follows:

Manual reading systems The simplest system is to use a portable terminal instead of the reader's notebook. In this way, the reader's route is programmed and the company employee simply has to key in the reading into the terminal. This type of reading requires the employee to travel to the meter location, with all the attendant difficulties.

Other systems consist of a codifier adapted to the gas meter counter, which sends the counter value from a remote location, by means of electrical conductors, to an external device which may be situated at an easily accessible location, and from which the information may be taken by means of a portable terminal.

While these systems increase the meter reading productivity, they are still subject to the fact that the reading is carried out on a counter to counter basis.

Concentrators The term concentrator is applied to the electronic equipment (usually installed at a location easily accessible for the utility company) to which are connected a set of counters. This equipment enables the 4 reading and recording or consumption figures by means of a display, or they may be read directly through a portable terminal which may be connected to the concentrator.

One such concentrators has been developed in Spain by the present Applicants, and has been on the market for several years.

Radio Frequency System Each meter is linked to a codifier, a power supply and a radio frequency transceptor. A data receptor unit, which can be either fixed or mobile, receives, when requested, the readings of the meters it is linked up to. Its present configuration does not contemplate acting on electrovalves.

Telephone System Similar to the abovet with the only difference that it uses a telephone line for transmitting data form the meter to the utility company. Each meter is provided with a modem to perform this function.

A major functional difference with this type of telephone transmission equipment arises from the origin of the communication, there being two types of equipment: those where the call is generated by the meter itself, and those where the call is generated by the gas utility company, which "activates" the counter and requests the reading from it. Another difference which can be observed is whether the equipment requires an exclusive switchboard telephone line or whether it can share the userls line.

PLC System There exists as well a type of equipment which performs transmission by modulating the data and injecting it into the main electrical network itself. Therefore each meter uses the low voltage installation as channel for the transmission of data between itself and concentrating device, usually installed at the medium voltage-low voltage transforming station feeding the area involved. The concentrator installed at the transforming station handles the readings of the meters belonging to it, and generates printouts or creates files with the corresponding data, which are later collected by the utility company. These systems have been developed in the U.S.A., Italy, Spain, Japan and France.

As regards the second group (remote supply cutoff systems) this has the aim of cutting off the gas supply on the part of the utility company, without having to enter the user's household.

Among the better known systems to carry out such a procedure, it is worth noting equipment developed in the U.S.A., which performs cutoff by means of a valve mounted on the meter and linked to a cable (maximum length: 30 m) which provides the interconnection between said valve and an outside connector, through which the valve-is acted upon, by means of a portable terminal. The reopening of said valve is manual, and is performed by means of a special tool, which means that the person authorized to do so must have access to said tool.

Finally, as regards the third group (intelligent cutoff systems) it may be said that an automated meter is manufactured in Japan which does not allow automatic reading, but incorporates a processor and a set of sensors, which allow detection of:

6 - Consumption of an excessive gas flow. - Consumption of gas for excessively long periods. - Earth tremors.

Carbon monoxide in the surroundings.

According to these alarms, the system acts upon a valve located inside the meter, and performs the gas cutoff.

It must be noted that this system does not allow remote cutoff of the gas supply by the utility company.

From all the above it may be deduced that none of the existing systems solves simultaneously and satisfactorily the three fundamental questions stated at the beginning (reading of gas consumption figures, supply cutoff and access to the user's household).

However, the system hereby proposed solves simultaneously all three questions, since it is devised to perform all the functions of a reading station, containing the counter values of the meters connected to it, allowing, as well the manual reading or by means of a portable terminal, or even through a telephone line, PLC system or others, provided the suitable interfaces are fitted, with the advantage over other individual systems that the cost of one interface is spread between all the meters connected to the station.

Basically, the system includes: the gas meters with their corresponding volume impulse emitter; cutoff valves; a concentrator and a portable terminal, all of them suitably interconnected to achieve the functions and aims intended.

---7 Furthermore, it drives from a remote location the cutoff valves installed in series with the meters, so that both can be installed in the user's household. By means of the same portable terminal used for reading, it is possible to reopen or cut off any valve. In addition, the system itself provides continuous control of certain variables, which would cause the automatic cutoff of the corresponding valve, in case their values should exceed certain preset validity limits. Such would be the case of: excess flow, short circuit or open circuit on the wires linking the meter or the valve to the concentrator, gas leakages, etc. For the performance of all the above stated functions it is not required to enter the user's household.

The use of a concentrator linked to the valves enables a significant saving in the installation of household gas, since the individual cutoff facility for every meter makes it possible for these, together with the valves, to be installed inside the user's house, thus eliminating the need for a r.eter room, and it also allows the use of a general conduit with branches for every user.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shotis a diagram corresponding to an impulse emitter which forms part of the system of the invention, and Figure 2 shows an illustration of the different blocks referring to the corresponding elements and/or devices which, as a whole, and suitably linked and electrically connected together, constitute the system of the invention, including two meters arranged in series.

8 As can be seen, the system is made up of a concentrator 1,. to which may be connected a number of meters 2, up to a maximum of 32, there being linked to every meter a special cutoff valve 3, disclosed and claimed in our co-pending U.K. Patent application no.

(our ref. 33451M), which will obviously permit the flow of or cut off the gas coming from the mains supply pipe 4, from which there diverge the corresponding branches 5, to which must be fitted each valve 3 and metering device 2. As is also known, the counter 6 of each meter 2 will be connected to the cutoff valve itself 3. The connection of each valve 3 to the concentrator 1 is made through a corresponding conduit 7, while between the valve 3 and the counter 6 associated to it, there will be another conduit 8.

The whole assembly will be complemented by a portable terminal 9, optically linked, as at 10, to the concentrator 1.

As to the characteristics of the gas meters 2, these may be the ones traditionally fitted in the user's households, provided said meters are equipped with a volume impulse emitter like the one shown in Figure 1, which includes an emitter contact 11 of the type known as potential free contact type, which is complemented with an array of resistances 12 and 12'. Said emitter will be connected, as may be expected, to the concentrator 1, through the emitter terminals 13. The most suitable values for the resistances 12 and 121 are 750 ohms 1% for resistance 12' and 240 ohms for resistance 12. With the contact open, the impedance is 3150 ohms 1%, compared to 750 ohms 1% when the contact is closed.

The concentrator 12, for its part, is an electronic device capable of withstanding the connection M value.

9 of up to 32 gas meters (two wires each) and 32 cutoff valves (two wires each). Its functions are as follows:

- Reading the counter 6 values on each of the meters 2, and viewing on the alphanumeric LCD display provided.

- Monitoring of the proper operation of the system, detection of one or more alarms among the following:

- Short circuit between the wires joining it to any of the impulse emitting devices.

- Open circuit between the wires joining it to any of the impulse emitting devices.

- Maximum flow through a meter, exceeding a preset - Automatic cutoff of the valve of the conduit where one or several of the foregoing alarms was detected.

- Periodic monitoring of the condition of the valves 3, and automatic cutoff of one or several of them in case a short circuit or open circuit is detected in the wires 7,8 of said valve.

- Checking of system internal parameters, and generation of the corresponding warning systems, through the alphanumeric display: - Battery status - Status of the data storage RAM memory. - Status of the alphanumeric display.

The device is equipped with a battery which allows it to continue working even when the mains power supply fails.

The device has a non volatile EPROM memory area automatically to store the data contained, in case of a mains voltage failure for a period of time exceeding the battery duration period.

The device has a two way infrared optical port 10 for the connection of the portable terminal 9, through which it is possible to transmit commands to the system, and receive information, the nature of said commands being as follows:

Carry out a test on the display and the RAM memory Save data on the EPROM memory zone. Preset the counter value for one channel. Preset the serial number of a meter. Preset the maximum allowed flow rate for each channel Erase the alarms of one or all the channels.

- Reopen, cut off or deactivate a valve.

- Reading the information contained: counter values status of system and alarms.

The device has a connector 14 enabling remote reading through switchboard telephone line, PLC or radio channel, using a suitable modem.

As to the portable terminal 9, it may be any of the currently existing ones on the market, provided it has the following minimum characteristics.

A RS232-C serial port An optical interface compatible with that of the z, concentrator A sufficient RAM memory capacity to contain the data and programme to be stored in it.

4 12

Claims

1. A system for remote reading and cutoff of domestic gas meters which, being devised to enable the remote reading and cutoff of a number of meters, without having to enter the user's household, is characterized by being made up of an electronic concentrator to which are connected electrically and independently a number of meters, each one of which is provided with a special cutoff electrovalve, through which a connection has been made between the concentrator and the respective meter; each meter also being fitted with a volume impulse emitter linked to an array of resistances connected in series and in parallel; with the particular feature of including as well a portable terminal optically linked to the concentrator itself, which terminal enables the respective commands for the opening and shutting of any of the electrovalves to be given, as well as to obtain the information relative to the meter counter values, general parameters, status of alarms, etc.

2. A system for remote reading and cutoff of domestic gas meters, as claimed in Claim 1, characterized in that the electronic concentrator also includes a connector for linking up to a modem which enables reading through a switchboard telephone line, PLC radio channel.

3. A system for remote reading and cutoff of domestic gas meters, as claimed in Claim 1 or Claim 2, characterized in that the impedance of the emitter from the outside has two possible values, which are 3150 ohms 1% or 750 ohms 1%, depending on whether the contact is open or closed.

j 13

4. A system for remote reading and cutoff of domestic gas meters substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

Published 1990 at The Pa.e,-,,.0flice.S.,atcHo,.ise.66 71 High Holborn. London WC1R4TP. Further copies maybe obtained from The Patent Office. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1187