FR2653554A1 - Electronic water meter allowing remote measurement of consumption - Google Patents

Abstract

The device according to the invention is an electronic meter allowing remote reading of consumption, without the requirement of entering the premises of the subscribers. It includes an electronic subscriber meter counting the pulses emitted by a screw (impeller) driven by the water. It is supplied with energy by another screw driving an electric generator. The content of the meter is periodically emitted in the form of ultrasound propagating through the water and received by another general meter. All the data are managed by a central processing unit capable of transmitting its data via the telephone network to the central computer.

Description

TECHNICAL DESCRIPTION
The present invention relates to water meters, and more particularly to electronic meters that can be raised remotely.

 In known systems of this kind, such as, for example, the system marketed under the name of MAYA, the transmission of information is carried out by a cable drawn between the meter and a recording unit common to a building or a lot. pavilions.

 Electronic counters are also known which count pulses generated by the rotation of a wheel or a propeller. This technique is directly derived from mechanical counters. In fact, the number of turns made by the wheel or the propeller is counted electronically instead of being counted mechanically as was traditionally the case. In meters that can be read remotely, there is generally a transmission of the electrical impulses delivered by the wheel, while the counting takes place in the central unit.

 All these devices have in common the defect of requiring electrical wiring consisting in ensuring a connection between the central unit e and the meter, or in bringing the electrical sector to supply the autonomous electronic meters. These cables are very expensive, which limits the advantage of these devices.

 Electronic meters without transmission could certainly be powered by batteries, but they should be changed periodically.

 The device according to the invention avoids these drawbacks, since it requires no wiring or the maintenance of any battery. In addition, the cost of making the meters is lower than that of known devices.

The invention relates to an electronic water meter, making it possible to record consumption remotely, comprising
- an electronic subscriber counter using a technique
conventional propeller or wheel (1), (6), (7).

- a general counter (2), (8), (9), which can be placed at
the entrance to a building, subdivision or any
set of subscribers, using a technique analogous to
previous.

- means (3), (5), making it possible to emit ultrasound
capable of constituting the remote read signal,
by propagation in water.

- means (4), (6), allowing reception of the signal
ultrasonic.

- a central unit (12) intended to process the information
of consumption.

 According to another characteristic, at least one of the electronic counters (1) or (2) is supplied with electrical energy by a paddle wheel or a propeller (13) or (14), driving an alternator or a dynamo ( 15) or (16), suitable for charging a battery (17) or (18).

 According to another characteristic, the means making it possible to emit ultrasounds or those making it possible to receive them use piezoelectric transducers (3) or (4), immersed in water or fixed to the wall of the pipe.

 According to another characteristic, the instants of transmission of the subscriber counter (1), all different from each other, are managed temporally by means of a clock (19) with quartz or equivalent, the instant of transmission allowing the central unit to identify the sending subscriber counter.

According to another characteristic, the central unit (12) consists essentially of a microprocessor capable of managing the consumption of each subscriber, of comparing the sum of consumption with that indicated on the general counter (9), in order to detect any failure or leak , and finally to transmit the information to a central computer
According to another characteristic, the transmission procedure consists in transmitting the binary content of the counter in the form of a series of dual-frequency pulses (one for zero, the other for 1), the instant of transmission to identify the issuer.

 According to another characteristic, the transmission means are not used, the subscriber counter having to be read by an operator.

 According to another characteristic, the receiver (4) is used as transmitter, in order to periodically readjust the clock (19), (3) then being receiver, read by the electronics (21).

 According to another characteristic, the electronic meter has only one propeller or impeller, allowing both to deliver energy while allowing metering.

 According to another characteristic, the transmission procedure is carried out using a single frequency.

 According to another characteristic, the subscriber counter-general counter link is amplified periodically, when the transmission conditions so require, by means of a repeater.

The characteristics and advantages of the invention will emerge more clearly from the description which follows, given with reference to the appended drawings, in which
- Figure 1 shows the general block diagram, allowing
understand the general operation of the counter and the
transmission of information
- Figure 2 shows a section of a counter
electronic.

 - Figure 3 shows the transmission procedure.

- Figure 4 shows the detailed circuit of the counter
subscriber.

- Figure 5 shows an electronic propeller counter
single, with the counting circuit, as well as that of
energy recovery.

- Figure 6 shows the detailed circuit of the counter
general.

 The operation of the counter can be understood by referring to FIG. 1.

We can distinguish a main pipe (10), from which more or less directly branch off (11), leading to subscriber counters (1). Upstream of the pipe (10) is placed a general counter (2). There are thus two meters in series, which will allow the proper functioning of the set of meters to be checked. It will thus be possible, thanks to the central unit (12) comprising a microprocessor, to carry out various operations, such as:
- compare the sum of the indications of all the counters
of consumption subscribers debited from the general meter. We
can thus detect a malfunction, as well
of the general counter as of one of the subscriber counters.

- detect leaks, observing a sudden increase
consumption of a subscriber.

The subscriber counter (1) comprises, in its most general version
- a propeller or wheel (6) with paddles such as those
used in conventional mechanical counters, which
performs a number of turns proportional to the volume of water
debited.

- another wheel or propeller, also rotated by the
water flow, the function of which is to charge an accumulator
cadmium-nickel, which powers all of
counter electronics, without the need to
worry about it.

- a piezoelectric transducer (3), capable of emitting
ultrasonic trains in the water but also to operate
as a receiver.

- electronics, itself comprising different elements
.. a storage battery (17), charged by a
food (15), itself receiving its energy from
the wheel (13).

.. an electronic counter (7), which counts the
impulses from the wheel (6) and keeps them in
memory until the clock (19) gives the signal
resignation. At this time, the transmitter (5), which comprises
a shift register addressed by the counter (7), goes
emitting pulse trains at two frequencies
separate f1 and f. These two frequencies, which
can, for example, be 35 and 45 Hz, correspond
to "O" and "1" of the binary digit contained in the
counter (7). This emission will be done by pulses
relatively narrow (10 ms for example), spaced
long enough for all the echoes
of an impulse in the different branches of the
have time to ease before
the arrival of the next impulse. We will take, for example, a period of 1 second. So all
subscriber counters (1) will transmit to the same
frequency, the differentiation being done only by
the instant of emission, as we will see later. As soon as the transmission is finished, the clock (19)
resets the counter (7) to zero. The show may have
place once a day.

.. a reception circuit (21), which is attacked by the
transducer (3). To avoid clock drift
(19), the general counter (2) can transmit, by means
of the transducer (4), a frequency f3 very
different from f1 and f2 (20 kHz, for example). The circuit (21), which includes a monitored amplifier
of a narrow band filter set on f3, can
be activated by this readjustment signal for, for example, 5 seconds. As soon as a signal leaves (21),
it forces the clock (19) to reset to one hour
specific for each subscriber, and which is displayed
by mechanical switches (22).

The general counter (2) includes elements similar to the previous one, namely
- a propeller (14), which supplies energy to the power supply
(16), charging the battery (18). In some cases,
may be easier to connect the general counter (2)
on the sector.

- a propeller or volumetric counting wheel (8), similar to
(6), attacking the electronic counter (9). The content of
this is read periodically by the microprocessor
(12).

- a transducer (4), which drives a receiver circuit (6),
comprising a frequency discriminator making it possible to
reconstruct the word transmitted by ultrasound. It is
then stored in the microprocessor (12), which
also records the transmission time. It is indeed,
as we have seen, which will identify the
subscriber account to which the
consumption for the last counting period, such
that it has just been transmitted by the ultrasonic signal.

The transducer can also be periodically attacked
by the generator emitting at frequency f (during a
fairly long duration (5 seconds for example) after
of a command carried out by the microprocessor (12). The
receiving circuit (6) is protected from transmission signal
of (20) by a suitable filter.

Referring to Figure 3, we can see an embodiment of the electronic counter, given for information, and, of course, not limiting. The circuit is made in CMOS technology. A quartz clock (23), is constituted for example by three binary dividers of 14 stages of type 4060 connected in series. If the quartz (26) which drives this clock has a frequency of 7.27 MHz, we can calculate that the counter will reset to zero every week. If we connect the eight most significant outputs of the last divider to the inputs of two comparators (24) of type 45858 of 4 bits each, connected in series, we will be able to obtain a signal as soon as the time displayed on a mechanical encoder has switch (25) will be reached.

 A different time will be displayed on each counter, so that the emission signals follow one another over time, without overlapping, in order to avoid interference. With 8 bits, we can therefore manage 256 counters, whose transmission times will be spaced 39 minutes apart. This is enough to get rid of the drifts of the meters. Indeed, two contiguous counters drifting in opposite directions will overlap after 19.5 minutes, or 1170 seconds. If you wish not to intervene on the meters more often than every 10 years, you need a frequency stability of 3.7.10-6, which can be obtained by sorting the quartz. The drift due to the temperature should not be taken account, because, in addition to the relative temperature stability of the water network, the fluctuations being the same for all meters, the drifts compensate for each other.

One can also consider the use of quartz of less good stability, by periodically carrying out a reset of the counter (23). For this, the input 12 of the three circuits 4060 receives each week a reset pulse, coming from an ultrasonic receiver (27), operating at a frequency different from that used for the transmission of the data. This ultrasonic signal is emitted by the central unit, via the general counter (2). All the individual counters (1) therefore simultaneously receive the readjustment pulse. Under these conditions, the clock (23) can be much less precise, which makes it possible to replace the quartz by an RC circuit operating at a much lower frequency. If the frequency is 443 Hz, one of the three 4060 frequency dividers can be deleted.

 The reception circuit (27) comprises a piezoelectric transducer, which may possibly be the same as that (28) used for transmission, a narrow band amplifier centered on the clock reset frequency, and finally a setting circuit. in the form of the rectified ultrasonic signal. This circuit is conventional enough not to have to be detailed here.

 The clock (23) is also used to fix the transmission frequency. We will use for this the output 14 'of the 4060 located in the middle of the chain of dividers, whose output frequency is 1.73 Hz. It constitutes the time base of the emission sequencer formed by the counters (29) and (30), the flip-flop (31) and the shift register (32).

As soon as the output (14) of the comparator (24) indicates, going high, that there is identity between the 8-bit binary digit available at the output of the counter (23) and that displayed on the encoder ( 25), the transmission sequence is initiated, by acting
- on the scale (31), constituted by the circuit 4013, and
whose output 2 goes low.

- on the shift register (32), constituted by the circuit
4021. Entry 9 is attacked by a circuit
RC differentiator, which loads into the register (32)
the content of the counter (30).

As soon as the counter reset input 2 (29), consisting of a binary counter 4024, returns to the low state, this is released, and the output 12 of the first stage delivers a frequency of 0.86 Hz, which will constitute the clock frequency of the shift register (32). As soon as this counter reaches the number 26 = 64, the output 4 goes to the high state, which brings back the output of the rocker (31) to the high state, from where the reset to the counter (29) and the end of the transmission sequence, since the output 12 giving the clock frequency remains at zero.

 The shift register (32) is attacked in parallel by the counter (30) on 5 bits of suitable weight so that, at the maximum foreseeable consumption, the number at the output of (30) does not exceed 25 = 32 per week . The serial output 3 attacks a shaping circuit, consisting of an R-C circuit followed by a Schmitt trigger.

The shaped pulse is used to trigger a multivibrator, constituted by another Schmitt trigger, which actuates the power transistor (34), which supplies the emission transducer (28). These triggers (33) can come from a 4093.

 The signal at the output of (32) always begins with a high start bit, which is essential to trigger the local clock of the receiver. This is achieved by connecting input 1 of the shift register (32) to the "plus".

 The counter (30), which totals the subscriber's consumption, is attacked by an operational amplifier (37), the inputs of which are connected to a coil (35), which detects the passage of a magnet fixed to the blades of the propeller (36). The number of turns performed by this propeller is indeed proportional to the water consumption.

The transducer (28) consists of a piezoelectric ceramic disc. It has a capacity C and constitutes with the inductance
L a series resonant circuit. This makes it possible to obtain a high voltage across the transducer, despite a low DC supply voltage of the power transistor. The duration of the emission is of the order of 0.3 s and the pulses are spaced by 0.86 s, which is necessary so that the ultrasonic signal can be sufficiently weakened before the arrival of the next impulse, given the multiple echoes that the water distribution pipe causes.

Figure 3 summarizes the essentials of operation
- curve a represents the output signal from
comparator (24), when the time of emission comes
to be reached.

- curve b represents this same signal at point A
that is to say after differentiation by capacitor C.

- curve c represents the clock signal entering
the register (32).

- the curve d represents the output of the register (32), after
shaping by the circuit (33).

- curve e, which represents the ultrasonic signal received
by the general counter transducer, illustrates well the
slow signal decay, as a result of
multiple echoes from the complex structure
a distribution pipe (elbows, nozzles,
section changes, etc.). We therefore understand that
signals should be as far apart as possible.

 FIG. 4 represents a first embodiment of a subscriber counter according to the invention.

 Inside the meter body (1), which can be made of stainless steel for example, there are two axial propellers (13) and (6).

The propeller (13) is devoted to the production of electrical energy necessary for the supply of electronic circuits. It is supported by an axis, itself held in the axis of (1) by a spider fixed in the ring (38). The propeller (13) can rotate freely around this axis. During its rotation, the propeller (13), which is made of a ferromagnetic material (iron, nickel, ferrite, etc ...), causes a variation in the reluctance of the magnetic circuit (39), (40) . This consists of a laminated iron or ferrite core (40), which is polarized by a permanent ferrite magnet (39). The flux variations thus generated cause induction in the coils (41), similar to what is known in variable reluctance alternators.

 Section a-a in Figure 2 shows the magnetic circuit. Note that, to obtain good efficiency, the wall of the body (1) must be as thin and as little conductive as possible. For example, we can use a wall of 1 mm of stainless steel or 3 mm of plastic.

 The second propeller (6) is mechanically and magnetically independent of the first.

 It can therefore rotate freely around its axis, which coincides with that of the body (1), and which is supported by a spider (42), which also supports the ultrasonic transducer (3). A magnetic circuit, similar to the previous one, makes it possible to obtain electrical pulses suitable for driving the electronic counter (30) (Figure 2). The variations in reluctance cause induction in the coil (35), and ultimately pulses each time a blade of (6) closes the circuit (39), (40). For the water count to be as precise as possible, (6) must be as free as possible. For this, the permanent magnet (39) will be as weak as possible, and in any case just sufficient for the pulses from (35) to be usable, taking into account the amplifier (37).

 Figure 4 shows another embodiment of the subscriber counter.

 It always has two independent propellers (6) and (13), with the same concern of not affecting the accuracy of the measurement by the mechanical resistance opposed by the electricity generator. This time, they are supported by a single axis (43), around which they can rotate freely. This axis (43) is supported by the flange (44), which can be removed without disconnecting the meter, for maintenance purposes.

The piezoelectric ceramic (3) is directly fixed to the wall of the body, so as to emit in the direction of the general counter. It is fixed on an impedance adapter (45), making it possible to adapt the impedance of ceramic, Zc, to that of water, Ze
One uses for this a medium of impedance VZ Ze ', and of thickness equal to N / 4. Various plastics, as well as aluminum, have a suitable impedance for this application. The interesting frequencies can go from 20 to 40 kHz. At 40 kHz, the thickness of dans, in plexiglass for example, is of the order of 1 cm. To simplify the implementation, it is advantageous to directly use the wall of the meter body (1) as an adapter. This requires the use of meter body materials either cast aluminum or plastic (AS, polystyrene, etc.). It is advantageous to give a curvature to the face of (45) in contact with the water, so that the emerging acoustic waves are substantially parallel.

 We recognize in Figure 4 the magnetic circuit (40) and the coil (41), which, placed opposite (13), allow to extract electrical energy from the hydraulic energy of the flow.

 All of the electronics are placed on a printed circuit (46), housed in a box integrated into the body (1) of the meter, and sealed by a plate (47). The meter can thus be immersed in a trench filled with water without affecting its operation.

Furthermore, the electrical energy obtained from the rotation of the propeller (13) is used to charge accumulators (17), making it possible to store this energy over a very long period.

 In the event that the counter is not used for a period of the order of one year, the transmission, limited to the first bit (of "start"), would cease. To reactivate the counter, it is then necessary to consume a few tens of liters of water, which cannot be counted. However, the central computer will be able to make the correction. So we see that the meter can be forgotten for many years in the ground. Any failure will, in any case, be detected by the general counter.

 Here, instead of using as before a single-frequency transmission with "start" bit and local clock located in the receiver, two transmission frequencies are used, one representing the binary digits 0, and the other the binary digits 1.

 Figure 5 shows a simplified version of the subscriber counter.

 The meter body (1) is a simple stainless steel or plastic tube, in which is fitted a fixed propeller (48), the central part of which supports an axis, around which another propeller (49) can rotate freely. To increase the efficiency of the fluid drive, the inclination of the blades of (49) is opposite to (48), similar to what is encountered in multi-stage gas turbines. Opposite the propeller (49), the fixed propeller (48) supports on its axis a piezoelectric ceramic (3), which is extended, in the upstream direction of the water flow, by an adapter d impedance (45), while the other face of (3) is connected to (48) by a layer of foam rubber.

The magnetic circuit is analogous to what has been described previously. It comprises two permanent magnets (39) with ferrite, and a core (40) which can be made of laminated iron or ferrite, and which is surrounded by a coil (41) playing the double role of generator of electrical energy and pulse generator, using the circuit in Figure 5c.

 Diodes D charge the batteries (17) The charging current of these batteries induces a pulse across the resistor R, which is amplified by the operational amplifier (37). The diodes D 'play the dual role of limiting the charge of (17) and of providing a pulse across the terminals of R, even when the batteries (17) are fully charged.

 As in the previous embodiment, the electronics must be housed in a waterproof housing, integrated into the body of the meter, and not shown in FIG. 5. It will also be possible, in certain cases, to advantageously drown the electronics in a plastic impregnation.

FIG. 6 represents a repeater, which, in the case of a long distance between the subscriber counter and the general counter, is placed so as to relay the ultrasonic signal, which, otherwise, would be too weakened. It basically involves
- a receiver (4), which can advantageously be constituted
by a piezoelectric ceramic, adapted by a
thickness / 4 of plexiglass.

- an emitter (3), which can also consist of a
piezoelectric ceramic adapted by a thickness X / 4
of plexiglass.

- a propeller (13) which, driven by the water flow,
constitutes with the magnetic circuit (41) a generator
of energy quite comparable to those mentioned above.

- a waterproof case (47), containing all of
electronics, which is also analogous to that
set out above. It has a battery
accumulators, and a reception amplifier which
triggers a timed transmission circuit as soon as a signal
was received by (4).

 FIG. 7 represents a general counter conforming to the block diagram of FIG. 1, but on which the energy receiver (8), (9) has not been mounted, which is indeed frequent, because the general counter can be connected to a telephone line for the transmission of information, as well as to an EDF line

The general counter includes
- a body (1), which is here a bent model. He can be in
cast iron, bronze, or plastic.

- a volumetric counting propeller (13), placed in the axis
of the downstream pipe, supported by the rod (43)
secured to the flange (44).

- a transducer (4), placed in the axis of the propeller, capable
to detect the ultrasonic signals emitted by the
subscriber counters or repeaters. He can too
be used to transmit signals to
periodically synchronize counter clocks
subscribers.

- a magnetic circuit (40) made of laminated soft iron or
ferrite, polarized by a permanent ferrite magnet (39),
and surrounded by a winding (41), at the terminals of which one can
count the impulses caused by the passage of the blades
of the propeller (13) which are made of ferromagnetic material
(ferrite, nickel, iron, etc.).

 The wires of the winding (41) and of the transducer (4) pass inside the support (43) and exit by a sealed socket (50), to be routed to the electronic unit comprising a microprocessor and a modem, for transmission to the central computer. This electronics is classic, and does not call for particular comments.

The processing carried out by the computer consists in continuously doing the following operations
- compare consumption on the general counter with the sum
consumption indicated by subscriber counters.

- check that each subscriber counter sends t periodically
his statement. Otherwise, notify the convenience store.

- follow the drift of the clocks of each subscriber counter,
and reposition the reception area. If two counters
have drifts in opposite directions and that they cross, we
will continue to follow them. If they simultaneously emit
time of interception, the two measures will be
canceled.

- check that consumption is consistent. In case of
excessive consumption, notify the convenience store.

 The invention can be installed in buildings, housing estates, and, in general, in all collective dwellings.

Claims (1)

CLAIMS (7). conventional propeller or wheel technique (1), (6), - an electronic subscriber meter using one that includes remote consumption reading, characterized in that 1) Electronic water meter enabling a previous . set of subscribers, using a technique analogous to the entrance to a building, subdivision or all - a general counter (2), (8), (9), which can be placed at a distance, by propagation in the water. ultrasound capable of constituting the reading signal - means (3), (5), making it possible to emit ultrasound. - Means (4), (6), allowing reception of the consumption information signal. - a central unit (12), intended to process the batteries (17) or (18). a dynamo (15) or (16), suitable for charging one or a propeller (13) or (14), driving an alternator or is supplied with electrical energy by a paddle wheel as at least one of the electronic counters (1 ) or (2) 2 ") Device according to claim 1, characterized in that the water or fixed to the wall of the pipe. piezoelectric transducers (3) or (4), immersed in or those allowing them to be received, use in that the means making it possible to emit ultrasound, 3) Device according to claims 1 or 2, characterized centrally to identify the sending subscriber counter or equivalent, the instant of transmission allowing the 'unit managed temporally by means of a quartz clock (19) characterized in that the times of transmission of the subscriber counter (1), all different from each other, are 4) Device according to the claims of 1 a 3, central computer, leak, and finally transmit the information to a compare r the sum of consumption with that indicated on the general counter (9), in order to detect any failure or capable of managing the consumption of each subscriber, essentially consisting of a microprocessor, characterized in that the central unit (12) is 5 ) Device according to claims 1 to 4, to identify the transmitter. zero, the other for 1), the transmission instant allowing the form of a series of dual-frequency pulses (one for the consists in transmitting the binary content of the counter under the 6) Device according to any one claims 1 to 5, characterized in that the subscriber counter transmission procedure to be read by an operator. that the transmission means are not used, the 7) Device according to claim 2, characterized in this receiver, read by the electronics (21). periodically reset the clock (19), (3) being while the receiver (4) is used as a transmitter, in order to 8) Device according to claim 4, characterized in this energy while allowing counting. propeller or impeller, allowing to deliver that the electronic meter comprises only one 9) Device according to claim 2, characterized in 10) Device according to any one of the claims of  1 to 9, characterized in that the transmission procedure  is done using a single frequency.  a repeater.  when the conditions of transmission impose it, by means  (1) - general counter (2) is amplified periodically,  characterized in that the subscriber counter link  11 ") Device according to claims 1, 2, 3 or 4,