JPH0315964B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) The present invention relates to a water meter equipped with a water leakage detection device for detecting water leakage from water pipes. (Technical Background of the Invention) The amount of water leaking from water distribution pipes and water supply pipes on the way from water treatment plants or distribution reservoirs to customers is currently around 10% of the total amount of water distributed, resulting in losses. Converting this into a monetary amount, assuming the water cost per ^cubic meter of 100 yen, amounts to about 200 billion yen per year. Developing new water sources to compensate for water leakage will require even more money. Therefore, it is urgent to know when water leaks occur and to suppress the amount of water leakage, but most water leaks occur underground, and it is difficult to detect them from above ground. A typical method for detecting underground water leakage that has been used in practice is a method using a listening rod. This can be done by placing a listening rod on the ground where the pipe is buried, by touching it directly with the buried pipe through a bored hole, or by placing it on an exposed part of the pipe, such as a fire hydrant or water meter. In this method, the vibration sound transmitted from the listening rod is mechanically or electrically amplified by contacting the sound rod, and the inspector listens to the sound through a headphone to determine the presence or absence of water leakage. However, this method requires skilled techniques to distinguish between water leak sounds and other noises, and it takes a huge amount of time and effort for surveyors with this technology to patrol all urban areas. There are problems such as slow progress in finding the location. For this reason, a correlated water leak detection device, which has recently been put into trial use, has been developed with the aim of automating water leak detection. This method attempts to determine the location of a water leak by cross-correlating signals from vibration sensors attached to two fire hydrants. but,
This has the following drawbacks. Firstly, data on pipe branching, pipe material, and pipe length in the survey section must be accurately known.Secondly, if there is a pipe branching between two sensors, Thirdly, branch pipes must be investigated separately.
Although it does not require skilled technology, there are limits to early detection of water leaks because it requires patrolling around the city. On the other hand, research conducted by the inventors has revealed that the sound of water leakage has a unique frequency component, and this fact can be used to detect water leakage sound with a sensor, and after amplifying it, determine whether it is a water leakage sound or not. A water leak detection device has been developed that distinguishes whether it is noise or not. FIG. 1 shows an outline of the configuration of such a water leakage detection device, in which water leakage sound and noise detected by a sensor 21 are converted into electrical signals and input to a waveform shaping circuit 22. In the waveform shaping circuit 22, the electrical signal from the sensor 21 is amplified, filtered by frequency, and discriminated by wave height value, etc., and a signal significant as a water leakage signal is set to a high level, for example.
Shape non-significant signals to low level. The signal duration integration circuit 23 integrates the time during which the input signal is at a high level and outputs a time-integrated signal T ₀ .
Further, the water leakage determination circuit 24 is a circuit that outputs a water leakage determination signal D ₀ when the time integrated by the signal duration integration circuit 23 exceeds a determination reference value. It is desirable that such water leakage detection devices be fixedly installed in the water supply pipes of each customer. The current number of water leaks is
Approximately 90% of this is accounted for by water supply pipes leading to customers, including branch points from water pipes.
This is because the water leakage detection device can be fixedly installed in the water supply pipe of each consumer, allowing the concentrated deployment of investigators, and making it unnecessary to conduct wasteful patrols to investigate areas where there is no water leakage. Moreover, by including such a water leakage detection device with a transmission circuit, it becomes possible to efficiently collect water leakage data via a telephone line. Therefore, as shown in FIG.
4, a water leakage signal storage circuit 32 counts and stores the number of occurrences of the water leakage determination signal detected by the water leakage detection circuit 4, and a display circuit 3 comprising a display drive circuit and a display for displaying the number of water leakages from the stored water leakage signal.
3. A transmission circuit 34 is provided for transmitting the stored water leakage signal. Note that the power supply circuit 20 is a circuit that supplies power necessary to operate the above circuit. By the way, even in water meters that measure water usage, measurement data can be sent through a communication circuit using a transmission circuit, and water meter reading work is an automatic meter reading process that uses a telemeter system using a communication line, along with electricity meters, gas meters, etc. There is a shift towards a new method. FIG. 2 is a system diagram of an automatic meter reading system using a communication line connected to a water leak detection device. A data processing device (host computer) 1 installed at the center is connected to a customer's home network control device 5 through a center-side network control device 2 and an exchange 3 during nighttime hours when communication lines are relatively idle. call. At this time, the no-ringing trunk 4 operates to distinguish it from a normal telephone and prevent the telephone from ringing. Home network control device 5
In addition to the telephone 6, there is a power meter 7a, a gas meter 7b, a water meter 7c, and a water leakage detection device 7.
d is connected, and one of the electric meter, gas meter, water meter, and water leak detection device is selected depending on the business entity code or equipment identification code at the time of the call. When a water leak detection device is selected, this output signal is sent out and can be read by the data processing device 1. Furthermore, since the water meter and the water leakage detection device are installed at approximately the same location, they can be integrated, resulting in miniaturization and reduction in installation costs. FIG. 3 is a layout diagram showing an example of installing such an integrated water meter in a domestic water supply system, in which a water supply pipe 13 is branched from a water distribution pipe 11 by a water distribution faucet 12. , the water supply pipe 13 is connected to a stop valve 14,
It is connected to a water supply device via a water meter 8 in which a water leak detection device and a water meter are integrated. Water meter 8
The output signal of the water leak detection device inside is taken out from the output terminal 9 and connected to the home network control device 5 via the cable 17. [Problems with the background technology] However, in the transmission method shown in Figure 2, in order to read the water usage amount and detect water leaks from the host computer side, it is necessary to call each of the water meter and water leak detection device. First, there is the problem that not only do complicated processing procedures have to be followed, but the line is monopolized for a long time. Even when the water meter and water leakage detector are integrated as shown in FIG. 3, the problem is the same because the transmission is performed separately. [Object of the Invention] The present invention has been made in view of the above problems, and an object of the present invention is to provide a water meter with a water leakage detection device that is capable of efficiently reading a flow rate meter and detecting water leakage. [Summary of the Invention] For the above purpose, the present invention includes a water leakage detection device connected to a water pipe, a flow rate metering device that integrates water usage, and a water leakage detection device that accumulates water leakage signals generated by the water leakage detection device. 1 storage section, a second storage section that accumulates the flow rate signal generated in the flow metering device, and a communication line that stores the storage contents of the first storage section and the storage contents of the second storage section. The system includes a transmission circuit equipped with a transmission control circuit that performs control to send data to the central processing unit through the communication line in a predetermined order in accordance with commands from the central processing unit. Meter reading data and water leakage detection data can be obtained simultaneously with a single call for meter reading, and the efficiency of flow rate meter reading and water leakage detection can be improved. [Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a water leakage detection device provided in a water meter according to the present invention will be explained. The fact that this water leakage sound has a unique frequency component can be used to generate other noises, such as the noise generated from water faucets, noise from passing vehicles, noise from machine operation in factories, and noise from work at construction sites. It is used to distinguish noise from noise such as noise. Figure 4a shows an example of the power spectrum obtained by converting the sound of running water when the faucet is opened into an electrical signal using a pressure-electrical converter and using a fast Fourier transform analyzer, and Figure 4b shows an example of the power spectrum obtained using a fast Fourier transform analyzer. , c is the sound of water leakage from two different lead pipes with a diameter of 20 mm buried 1 m underground (in the case of water leakage rate of 5/min)
This shows an example of the power spectrum of . From these data, the power spectrum of water leakage sound has a lower limit frequency of about 1KHz and an upper limit frequency of several kHz.
It turns out that it is 10KHz. Furthermore, it can be seen that the power spectrum of the sound of running water from a faucet, which must be distinguished from the sound of water leakage, is mainly distributed below 1KHz. Moreover, this distribution situation shows almost no change depending on the pipe material, pipe length, pipe damage condition, soil condition, etc., which were previously considered to have an effect on water leakage signals. . When the leakage flow rate is around 5/min, the influence of external noise can be ignored for this kind of water leakage sound, but when the water leakage sound is at a minute flow rate or less than this, the sound pressure level of the sensor decreases and the water leakage is affected by external noise. Difficulty distinguishing between sound and noise. However, it has been found that these external noises decrease late at night. In addition, as water demand decreases late at night, the water supply pressure increases due to a decrease in the head of friction loss in the pipeline from the distribution reservoir to the demand end, and the leakage flow rate increases, making the leakage sound itself louder. Therefore, by increasing detection sensitivity late at night when external noise decreases and water leakage noise increases, it becomes possible to detect even smaller water leaks. In addition, water leaks occur due to corrosion of water supply pipes, water distribution valves, etc., destruction due to external force, loosening of fasteners, poor construction, etc. Once water leaks occur, they will continue to occur unless repaired, and natural recovery will occur. It's impossible to do that. On the other hand, it is clear that water faucet noise, which is the biggest source of noise, only generates sound when water is used. Other noise sources such as vehicle noise,
It is extremely rare for various mechanical sounds and construction work sounds to occur continuously for 24 hours. Therefore,
By integrating the duration of the sound and determining a water leak only when this integrated value exceeds a preset criterion, it can be distinguished from other noises. The integral value of the duration will be referred to as the time integration rate C, and is defined as follows. C=Σ(ta−tb)×100/T Ta∈τ _a tb∈τ _b tb＜ta τa={t|f(〓,t)=Er, f′(〓,t)＜0} (1) τb={t|f(〓,t)=Er, f'(〓,t)＞0} However, T is the time from the start to the end of the measurement of the time integration rate, Er is the judgment reference voltage, f(〓, t) is a function representing the water leakage signal voltage, the vector 〓 represents a plurality of factors that influence the waveform of the water leakage sound, and t represents time. Further, f' (〓, t) is the time differential of the water leakage signal voltage. In other words, the time integration rate C is the ratio of the integrated time to the measurement time T when the water leakage signal voltage is time-integrated over a period in which f(〓, h) is greater than the judgment reference voltage Er within the measurement time T. be. FIG. 5 is a block diagram showing the configuration of the water meter according to the present invention, which is roughly divided into a water leak detection section 19, a flow metering section 39, a transmission circuit 34', and a power supply circuit 20. These configurations will be described in detail below. Sensor 21 The sensor 21 is a converter that converts pressure caused by acoustic signals or vibrations into electrical signals, and various known types can be used. Waveform Shaping Circuit 22 FIG. 6 is a configuration diagram of an embodiment of the waveform shaping circuit 22. The amplifier circuit 25 amplifies the electrical signal from the sensor 21 by 1×10 ⁴ to 1×10 ⁶ times, and extracts the main component of the signal by using a bandpass filter 26 with a low cutoff frequency of 1KHz and a high cutoff frequency of 10KHz, for example. pass. This alternating current electric signal is converted into a positive signal by an absolute value amplification circuit 27, and a comparator circuit 28 converts the negative signal into a positive signal.
is input. The comparator circuit 27 converts only input signals higher than the reference voltage +Er into constant voltage signals and outputs the constant voltage signals. Amplifying circuit 25 This is an AC amplifying circuit A ₁ having an input resistor R ₁ and a negative feedback resistor R ₂ , and amplifies the sound pressure signal from the sensor 21 and sends it to the next bandpass filter 26 . Now, let the sound pressure signal level at the pressure receiving part of the sensor 21 be SdB (for example, 1 μPa pressure is OdB),
Pressure sensitivity KdB of sensor 21 (for example, per 1 μPa
The sensitivity at which a voltage output of 1V can be obtained is OdB), and the gain of the amplifier circuit 25 is AdB. However, it is assumed that the attenuation of the signal component in the bandpass filter 26 can be ignored, and the gain of the absolute value amplification circuit 27 is
If OdB, the input signal level of the comparator circuit 28 is
EdB is given by equation (2). E=S+K+A (2) Now, the output signal level of the amplifier circuit 25 is OdB,
That is, E=0 (in the case of sine wave output, the effective value is
The gain of the amplifier circuit 25 is determined based on the design standard that a voltage (corresponding to 1V) can be obtained. Pressure sensitivity K
If -220dB is adopted as a general value of , then A = 220-S (3) from equation (2). Figure 7 shows the leakage flow rate from two different lead pipes with a pipe diameter of 20 mm buried 1 m underground: 2/min, 5/min.
/min, 10/min, sensor 21
FIG. 3 is a diagram in which the sound pressure level at the pressure receiving section was measured twice each and plotted. Now, in order to satisfy the above-mentioned design criteria for water leakage sound caused by a water leakage flow rate of 2/min, A = 100 dB can be obtained by substituting S = 120 dB into equation (3). Therefore, it is sufficient to use an amplifier having a gain of this level. Bandpass filter 26 Filters out the loudest sound of water use among background noises. From the measured data in Figure 4, the lower limit cutoff frequency of this filter is approximately 2kHz, and the upper limit cutoff frequency is 10kHz.
Hz, attenuation characteristic is 24dB/octave ~
Approximately 30dB/octave is desirable. As a filter having such characteristics, a commercially available active filter can be used. Absolute value amplification circuit 27 As shown in Fig. 6, this has inverting amplifiers A ₂ and A ₃ with a gain of OdB, and in the same figure, for example, the values of resistors R ₃ to R ₇ are selected as follows. . R ₃ = R ₄ = R ₆ = R ₇ = R, R ₅ = R/2 At this time, if the input signal voltage is negative, the output of A ₂ is clamped by the diode D ₂ and becomes approximately 0V. At this time, the diode _D1 becomes reverse biased and has a high impedance, so the amplifier _A3 inverts the negative input signal and a positive voltage signal is obtained as the output of the circuit. Then when the input signal voltage becomes positive, the output voltage of A ₂ becomes a large negative voltage equal to the input signal voltage and is applied to resistor R ₅ . resistance
R ₅ and R ₆ constitute an adder, and R ₅ =
Since R ₆ /2, a positive output having the same magnitude as the input signal voltage can be obtained as the output of this circuit. As described above, with this circuit, it is possible to obtain an absolute value signal voltage in which the positive part of the AC signal voltage remains unchanged and the negative part is inverted. Comparison circuit 28 As shown in FIG.
If less than Er, its output is diode D ₃
In the opposite case, it operates as an infinite gain amplifier and goes to a high level limited by the supply voltage. Next, a method for determining the reference voltage Er will be explained.
In the above equation (2), if K=-220 dB and A=100 dB, then E=S-120 (4). On the other hand, by rewriting equation (4) using relational equation (5) between the peak value eV of the limiting wave voltage and its level EdB, equation (6) is obtained. E=20log ₁₀ (e/√2) (5) e=√2・10 ^S-120/20 (6) Figure 8 shows the comparison circuit 28 calculated for the range 100dB≦S≦120dB using equation (6). is the peak value eV of the input signal voltage. According to this, for example,
It can be seen that when determining a signal having a sound pressure level greater than 115 dB as a water leak sound, it is preferable to set the reference voltage Er to 0.795 V or less. Signal Duration Integration Circuit 23 FIG. 9 shows an example of the signal duration integration circuit 23, which has a memory circuit 45 and a counter 43 controlled by a timing circuit 44, and the output of this memory circuit 45. and pulse oscillation circuit 4
It is constituted by an AND gate 42 which sends an AND output to a counter 43 from the output of an AND gate G1 which inputs an output of 0, and the output of the waveform shaping circuit 22. The operation is as follows. The frequency of the pulse oscillation circuit 40 is set to be several times higher than the high cutoff frequency of the band filter included in the waveform shaping circuit 22 to ensure resolution. The timing circuit 44 has a built-in clock and outputs an integration start signal at the time set by the control input.
It has the function of generating a series of command signals such as INI, integration end signal INO, judgment execution signal DIO, and counter 43 reset signal RS. These signals usually occur on a daily basis, for example, the integration start signal INI at midnight and the integration end signal INI at 4 a.m.
It is set so that INO is output. The memory circuit 45 maintains the logic "1" state from the integration start signal INI to the integration end signal INO,
An AND gate 41 performs a logical product with a pulse, and supplies the pulse to an AND gate 42. The AND gate 42 digitizes the duration of the output signal of the waveform shaping circuit 22 by taking the AND of the output pulse of the AND gate 41 and the output signal of the waveform shaping circuit 22. By counting the output pulse train of the AND gate 42, the counter 43 calculates
After the integration start signal INI is generated, the integration end signal is generated.
Performs time integration of the waveform shaping circuit output signal until INO occurs. FIG. 10 is a waveform diagram showing the output waveform at each part in the waveform shaping circuit 22 and the signal duration integration circuit 23, in which FIG. 10a is an example of the output signal waveform of the bandpass filter 26, and FIG. This is an example of the output signal waveform of the value amplification circuit 27, in which the negative signal of a is folded around the OV line. Figure c shows a comparator circuit 28 that becomes high level when the signal in figure b is larger than the reference voltage Er.
This is the output signal waveform of the waveform shaping circuit 22. d in the figure is an output pulse train of the AND gate 42, and the number of pulses is proportional to the high level period of the output signal of the waveform shaping circuit 22. e is the integration start signal INI, f is the integration end signal INO, g is the integration period signal indicating the logic "1" state of the storage circuit 45, and h is the determination execution signal DIO, which is issued after the integration end signal INO and is used to determine water leakage. This is for operating the circuit 24. A reset signal RS is issued further after this and is used to initialize the counter 43. Water leakage determination circuit 24 FIG. 11 shows an example of the water leakage determination circuit 24, which is a binary parallel comparison circuit. Now, let the two binary numbers of k bits be X and Y, and the least significant number (LSD) of the binary number
The logic “1” of the binary number Y is X ₁ , the logic “1” of the most significant number (MSD) is X _K , and similarly the logic “1” of the LSD of the binary number Y
is Y ₁ , MSD logic “1” is Y _K , p _K , q _K , r _K
are defined as follows. _{p K = _ _ _ _ _ _ _ _ _} ∩ _K ( _K = 1, 2, ...,
K) However, _K and _K are the logic "0" signals of X _K and Y _K , respectively, ∩ is a symbol representing logical product, and U is a symbol representing logical sum. Also, logical symbols P regarding the magnitude of binary numbers X and Y,
When Q and R are determined as P=1 (X>Y) Q=1 (X<Y) R=1 (X=Y) (8), P=p _K U(p _K-1 ∩r _K )U(p _K-2 ∩r _K ∩r _K-1
) U... Q=q _K U (q _K-1 ∩r _K ) U (q _K-2 ∩r _K ∩r _K-1 ) U... R=r _K ∩r _K-1 ∩r _K-2 ∩……∩r ₁ (9). FIG. 11 shows the logic of equations (7), (8), and (9) constructed using an AND gate 50 and an OR gate 51, where the binary number A is the value of the counter 43 and the binary number Y is the judgment reference value. , the output P becomes the judgment output. In realizing the water leak detection circuit,
The portion related to the signal output of Q surrounded by the broken line is unnecessary. Further, the AND gate 52 is used to logically AND the determination execution signal DIO and the output P to output a water leakage determination signal D ₀ . The following describes the determination of water leakage. Figure 12 shows the result of calculating the relationship between the magnitude S (dB) of the sine wave input signal to the comparison circuit 28 and the time integration rate (%) based on the following equations (10) and (11). .
Note that the parameter is the reference voltage Er (V). C=π−2θ/π×100 (10) θ=sin ^-1 (Er/Ep) S=20log(Ep/√2) (11) However, Ep is the peak voltage of the sine wave input signal S (dB) (V), π is the phase angle (radian) of the half wavelength of the sine wave, and θ is the phase angle (radian) shown in FIG. Now, assuming that the reference voltage Er=0.5V and the criterion for determining water leakage is a time integration rate C>40%, the input signal S to the comparator circuit 28 is required to be -7 dB or more from the graph of FIG. In other words, if you set Er = 0.5V and C = 40%, it will be determined that there is a water leak if an input signal greater than -7 dB continues to occur during the entire time period when the time integration rate is being measured. can. Also, for example, even if noise with a magnitude of +20 dB occurs at a time occupancy rate of 20% during the measurement period, the time integration rate will only be 98% x 0.2 = 19.6%, which is 40% of the water leakage judgment criteria above. Since it is less than 20%, it will not be determined that there is a water leak. Flow metering section 39 This includes the flow rate signal detection circuit 36 and the flow rate integration circuit 3.
7. It consists of a display circuit 38 and a power supply circuit 35, and the flow signal detection circuit 36 consists of a proximity switch that detects the impeller rotating in response to the water flow and a waveform shaping circuit that converts the passage of the impeller into a pulse signal. Become. The flow rate integrating circuit 37 has an integrating function of counting the pulse signals and increasing the integrated value of the flow rate by one unit when a pulse corresponding to a measurement unit flow rate (for example, 0.1) is counted. The display circuit 38 is a circuit for displaying the integrated flow rate value, and the power supply circuit 3
Reference numeral 5 denotes a circuit that supplies the power necessary to operate the flow metering section 39 described above. Since the configurations of the above-mentioned parts are well known, detailed explanations will be omitted. Transmission circuit 34' This is a main part of the present invention, and the configuration of one embodiment thereof is shown in FIG. According to this, the 4 bits connected to the upper 4 bits and the lower 4 bits of the water leakage signal storage circuit 32 are
Buffer registers 61-1 and 61-2, which are bit R-S flip-flops, are provided, and 4-bit R-S flip-flops connected corresponding to every 4 bits of the 32-bit output of the flow rate integration circuit 37 are provided. A certain buffer register 62-1,...
62-8 are provided, and each of these buffer registers is connected to bus line 60. Further, a line buffer 65, which is a bidirectional signal buffer for temporarily storing data contents during transmission and reception, is connected to the line connection terminal 63.
A receiving buffer 66 and a transmitting buffer 67 are connected to this line buffer, and a transmission control circuit 68 is further connected to both buffers 66 and 67. A control line 71 and a signal line 72 are led out from this transmission control circuit 68 to each buffer register. In addition, the device number code register 64
is, for example, a two-digit fixed storage device in which unique values depending on the type of water meter are stored. Before explaining the operation of such a transmission circuit, FIG. 15 shows an example of the format of transmission data sent to the home network control device. Figure 15 a is 1
The data format shown in FIG. 15B shows the bit configuration of one digit of data, and the direction of the arrow indicates the signal transmission direction, that is, the data is transmitted in order starting from the head of the arrow. The mark signal is a logic "1" signal that continues for a certain period of time, the space signal is a logic "0" signal that continues for a certain period of time, and the start code is a one-digit specific code predetermined to indicate the start of sending data. The stop code is a 1-digit specific code predetermined to indicate the end of sending data, and the instrument number code is a 2-digit specific code to distinguish the water meter model, water leak detection device model, etc., and the integrated flow rate value. is the flow rate value of the water meter and is 8-digit data, and the water leakage signal is 2-digit data representing the value of the water leakage signal storage circuit. One digit consists of 7 bits, as shown in Figure 15b.
Start bit indicating the beginning, BCD, as in
It consists of 4 data bits representing one digit of 1 or 1 hexadecimal digit, a parity bit for the data bit, and a stop bit representing the tail. Next, the operation of this transmission circuit will be explained. now,
Assume that a logic "1" signal is sent from the home network control device 5 to the line buffer 65 via the terminal 63 connected by a pair of signal cables. This is done by the data processing device 1 issuing the subscriber's telephone number and a number specifying the water leak detection device or the water meter with a water leak detection function (a number to distinguish it from other electricity meters and gas meters).
If the subscriber's telephone 6 is not busy, this signal is issued from the home network control device 5. Line buffer 65 is a bidirectional signal buffer, and terminal 63
Since the receiving buffer 66 has the function of outputting the signal input from the line buffer to the receiving buffer 66 and the function of outputting the signal input from the transmitting buffer 67 to the terminal 63, the receiving buffer 66 has the function of outputting the signal input from the line buffer to the terminal 63. If it is within the specified range, sends a transmission start signal to the transmission control circuit 68 to support the start of transmission.
Output to 3. As shown in the time chart of FIG. 16, the transmission control circuit 68 receives the transmission start signal and successively outputs a load signal, a mark signal, and a start code to 74. Next, when a data transmission signal is output to 75, the transmission buffer 67 inputs the data on the 4-bit bus line 60, and starts the start bit as shown in FIG.
The bus line data A ₀ , A ₁ , A ₂ , A ₃ , parity bit, and stop bit are transferred to the line buffer 6 in this order.
Output to 5. The line buffer 65 outputs the same time-series signal as the input to the terminal 63. The transmission buffer 67 adds the start bit, stop bit, and parity bit. Since the device number code has two digits, two sets of the 7-bit time-series signals are outputted in series from the transmission buffer 67. During this time, the selection signal from the transmission control circuit 68 is
The device number code register 64 that is output to 2 is selected. That is, only the signals from the registers selected by the selection signal are output to the bus line 60. Similarly, the buffer register 62- in which the flow rate integrated value 70 is set is
1, ..., 62-8, a signal for selecting the buffer registers 61-1 and 61-2 in which the water leakage signal 69 is set is applied to the signal line 72, and the transmission buffer 67
sequentially converts all of these signals into the time series signals shown in FIG. 15b and outputs them to the line buffer 65, so that the same time series signals are output to the terminal 63. When the final data is output, the data transmission signal from the transmission control circuit 68 that was output to the signal number 75 is turned off, and instead a stop code and a space signal are output to 74 to complete the entire transmission. The procedure ends. Various modifications can be made to the water meter equipped with a water leak detection device as described above. FIG. 17 shows another embodiment of the signal duration integration circuit 23, and the difference from FIG. 9 is that the pulse oscillation circuit 40
Instead, a voltage-frequency conversion circuit 46 is used. Voltage-frequency conversion circuit 46
is a circuit that outputs a pulse with a frequency proportional to the input voltage, but since the magnitude of the output signal of the waveform shaping circuit 22 is a constant value, it outputs a pulse with a constant frequency while the input signal continues. So the 9th
It has the same function as the circuit shown in the figure, and the signal waveforms shown in FIG. 10 are also the same. Next, an example in which the detection sensitivity in the middle of the night is increased will be described in detail. FIG. 18 shows a configuration diagram of one embodiment. The sensor 21, bandpass filter 26, and absolute value amplification circuit 27 are the same as those shown in FIG. Variable gain amplifier circuit 2
5' is the same as the amplifier circuit 25 in FIG. 6, except that the negative feedback resistors R ₁₁ and R ₁₂ are switched by the contacts a ₁ , b ₁ , and c ₁ of the relay 31. . The reference value variable comparison circuit 28' adjusts the reference voltages Er 1 and _{Er 2} by the contacts a ₂ , b ₂ , and c ₂ of the relay 31.
The comparator circuit 28 is the same as the comparator circuit 28 in FIG. 6, except that it has a structure that allows selection of the comparator circuit 28. The clock circuit 29 is
By applying set and reset signals to the memory circuit 30, the relay 31 is energized or de-energized. Further, the clock circuit 29 operates at an arbitrary time t ₁ ,
At t ₂ , the signals S ₁ and S ₂ are output to the output terminals 29b ₁ and 29b _2, respectively.
The output is adjusted to . Further, since the output terminals 29b ₁ and 28b ₂ are respectively connected to the set input terminal 30a ₁ and the reset input terminal 30a ₂ of the memory circuit 30, the memory circuit 30 is placed in the state "" by the signal _S1 at time _t1 . 1'' and the relay 31 is energized, and the signal _S2 at time _t2 causes the memory circuit 30 to be in the state ``0'' and the relay 31 is de-energized. When the relay 31 is in a non-energized state, the contact _C1 selects the feedback resistor _R1 of the variable gain amplifier circuit 25', and the contact _C2 selects the reference voltage _Er1 . In addition, in the energized state, contact C ₁ selects feedback resistor R ₂ and contact C ₂ selects reference voltage Er ₂
It is becoming more and more of a choice. FIG. 19 shows a time chart for switching the gain of the amplifier circuit 25' and the reference voltage of the comparator circuit 28'. (d) is a function of time t, and is given as follows with respect to FIG. Note that a in the same figure shows the output of the clock circuit 29, and b in the same figure shows the state of the relay 31. Now, if the time t such that t ₁ ≦t<t ₂ is a time in a late-night time zone, and the time t such that t ₀ ≦t<t ₁ and t ₂ ≦t is a time in a time zone other than midnight, then the amplifier circuit 25 The gain of ' and the reference voltage of the comparator circuit 28' are set as follows. Gain of amplifier circuit 25' = g ₁ (t∈τ ₁ ) g ₂ (t∈τ ₂ ) Reference voltage of comparison circuit 28' = Er ₁ (t∈τ ₁ ) Er ₂ (t∈τ ₂ ) However, the set τ ₁ represents a time in a time zone other than midnight, and the set τ ₂ represents a time in a time zone other than midnight. τ ₁ = {t|t ₀ ≦t ₁・t ₂ ≦t} τ ₂ = {t|t ₁ ≦t<t ₂ } Also, the magnitude of the signal and the magnitude of noise at the output end of the amplifier circuit 25' is given as follows. Size of output signal = U _s1 (t∈τ ₁ ) U _s2 (t∈τ ₂ ) Size of output noise = U _o1 (t∈τ ₁ ) U _o2 (t∈τ ₂ ) Also, amplifier circuit 25' The magnitude of the water leakage signal and the magnitude of the noise at the input terminal of are given as follows. Input signal magnitude = υ _s1 (t∈τ ₁ ) υ _s2 (t∈τ ₂ ) Input noise magnitude = υ _o1 (t∈τ ₁ ) υ _o2 (t∈τ ₂ ) Therefore, U _S1 = g ₁ υ _S1 , U _o1 = g ₁ υ _o1 (12) U _s2 = g ₂ υ _s2 , U _o2 = g ₂ υ _o2 , and now υ _s1 = υ _s2 ≡υ _s , υ _o1 = kυ _o2 ,υ _s =
If Nυ _o2 , then U _o1 = g ₁ kυ _o2 = g ₁ kυ _s /N (13). Therefore, from the condition U _s2 > U _o1 that the output signal in the late night time period is larger than the noise in the time period other than midnight, g ₂ υ _s > g1k/Nυ _s , that is, g ₂ /g ₁ > k/N ( 14) is obtained. The gains g ₁ , g ₂ of the amplifier circuit 25' that satisfy this condition
When using , even if Er ₁ =Er ₂ , it is possible to discriminate the water leakage signal which is smaller than the noise in time periods other than midnight, but in the late night time period. If equation (14) does not hold, the condition of equation (15) is additionally required. e _r1 = e _r2 > δ (15) However, δ is an appropriate positive constant. Next, an example based on the numerical examples in Table 1 will be described. To simplify the explanation, assume that the signal and noise are sine waves of the same frequency.

〔Effect of the invention〕

As described above, according to the present invention, the first storage unit stores water leakage signals, the second storage unit stores flow rate signals, and continuously sends out the stored contents to the communication line in a predetermined order. Since the system is equipped with a transmission control circuit that allows water leakage information to be collected with a single call for flow rate meter reading, efficient water leakage investigation is possible without the need for patrolling leakage investigations. At the same time, transmission lines can be saved.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of a conventional water leak detection device, Figure 2 is a configuration diagram of an automatic meter reading system including this, and Figure 3 is an example of the use of an integrated water leak detection device and water meter. A layout diagram, FIG. 4 is a power spectrum of running water sound and water leakage sound, FIG. 5 is a block diagram showing the configuration of a water meter according to the present invention, FIG. 6 is a circuit diagram showing an example of the configuration of a waveform shaping circuit, 7th
The figure is a graph showing the relationship between the leakage flow rate and the sound pressure level of the sensor pressure receiving part, Figure 8 is a graph showing the relationship between the sound pressure level of the sensor pressure receiving part and the peak value of the comparison circuit input voltage, and Figure 9 is a graph showing the signal duration time. A circuit diagram showing an example of the configuration of an integrating circuit, FIG. 10 is a waveform diagram showing output waveforms in a waveform shaping circuit and a signal duration integrating circuit, FIG. 11 is a circuit diagram showing an example of a water leakage determination circuit, and FIG. 13th graph showing the relationship between the input signal level and the time integral rate in the comparison circuit 28
Figure 14 is a graph showing a sine wave input signal, Figure 14 is a block diagram showing the configuration of the transmission circuit that forms the main part of the present invention, Figure 15 is an explanatory diagram of the format of the transmission data, and Figure 16 is the operation in the transmission circuit. FIG. 17 is a circuit diagram showing a modified example of the signal duration integration circuit, FIG. 18 is a circuit diagram showing a modified example of the waveform shaping circuit, FIG. 19 is a time chart showing its operation, and FIG. 21 and 21 are waveform diagrams showing the relationship between water leakage signal, noise, and reference voltage, FIG. 22 is a circuit diagram showing another example of a waveform shaping circuit, and FIG. 23 is a circuit diagram showing an example of a power supply circuit. be. 1...Data processing device, 7c...Water meter, 7d
... Water leak detection device, 8 ... Water meter, 19 ... Water leak detection section, 20 ... Power supply circuit, 21 ... Sensor, 22 ... Waveform shaping circuit, 23 ... Signal duration integration circuit, 24 ... ...Water leakage determination circuit, 25...Amplification circuit, 26...Band pass filter, 27...Absolute value amplification circuit, 28...Comparison circuit, 29, 55...
...Clock circuit, 30,56...Memory circuit, 31,5
7...Relay, 32...Water leakage signal storage circuit, 3
4, 34'...transmission circuit, 35...power supply circuit,
36...Flow rate signal detection circuit, 37...Flow rate integration circuit, 39...Flow rate measuring section, 61-1, 61-2,
62-1, 62-8... Buffer register, 63
...Terminal, 64...Instrument number code register, 65...
...Line buffer, 68...Transmission control circuit.

Claims (1)

[Scope of Claims] 1. A water leakage detection device connected to a water pipe, a flow rate metering device that totalizes water usage, a first storage unit that stores a water leakage signal generated by the water leakage detection device, and the flow rate metering device. a second storage unit for accumulating flow rate signals generated in the device; and
transmission in which the storage contents of the storage section and the storage contents of the second storage section are successively sent to the central processing unit side through the communication line in a predetermined order according to a command from the central processing unit connected to the communication line. A water meter with a water leak detection device, characterized by comprising: a transmission circuit equipped with a control circuit; 2. A water leakage detection device is installed in the flow path of a water pipe, and includes a sensor that detects sound pressure fluctuations that occur due to water leakage and propagates in the water, and vibrations that propagate through the pipe wall, and an amplifier circuit that amplifies the output of this sensor. , a bandpass filter that passes only the main frequency component of the output of this amplifier circuit, an absolute value amplifier circuit that converts the output of this bandpass filter into a negative polarity signal and a positive polarity signal, and outputs the negative polarity signal, and this absolute value. a comparison circuit that compares the output of the amplifier circuit with a predetermined judgment reference voltage and outputs a judgment signal; a signal duration integration circuit that integrates the output of the comparison circuit for a predetermined period of time over the duration of the signal; A water leakage determination circuit that compares the output of the integrating circuit with a preset determination reference value to distinguish noise from water leakage sound, and a water leakage signal storage circuit that counts and stores the number of water leakage determinations in the output of the water leakage determination circuit. A water meter with a water leakage detection device according to claim 1, further comprising a display circuit for displaying the contents of the water leakage signal storage circuit. 3. A water leakage detection device is installed in the flow path of a water pipe, and includes a sensor that detects sound pressure fluctuations that occur due to water leakage and propagates in the water, and vibrations that propagate through the pipe wall, and an amplifier that inputs and amplifies the output of this sensor. a bandpass filter that passes only the main frequency components of the output of the amplifier circuit; an absolute value amplifier circuit that converts the output of the bandpass filter into a negative polarity signal and a positive polarity signal and outputs the signals; a comparison circuit that compares the output of the absolute value amplification circuit with a predetermined judgment reference voltage and outputs a judgment signal; a signal duration integration circuit that integrates the signal duration of the output of the comparison circuit for a predetermined period of time; A water leakage judgment circuit compares the output of the duration integration circuit with a preset judgment reference value to distinguish between noise and water leakage sound, and the output of this water leakage judgment circuit is input and the number of times a water leakage is judged is counted. , a water leakage signal storage circuit for storing, a display circuit for displaying the contents of the water leakage signal storage circuit, a clock circuit for outputting a set signal or a reset signal at an arbitrary predetermined time, and a storage circuit for storing the set signal and the reset signal. 2. A water meter with a water leakage detection device according to claim 1, further comprising a switch for increasing the gain of the storage circuit and the reference voltage of the comparison circuit in the middle of the night when external noise has decreased. 4 A water leakage detection device is installed in the flow path of a water pipe, and includes a sensor that detects sound pressure fluctuations that occur due to water leakage and propagates in the water, and vibrations that propagate through the pipe wall, and an amplifier that inputs and amplifies the output of this sensor. a bandpass filter that passes only the main frequency components of the output of the amplifier circuit; an absolute value amplifier circuit that converts the output of the bandpass filter into a negative polarity signal and a positive polarity signal and outputs the signals; a comparison circuit that compares the output of the absolute value amplification circuit with a predetermined judgment reference voltage and outputs a judgment signal; a signal duration integration circuit that integrates the signal duration of the output of the comparison circuit for a predetermined period of time; A water leakage judgment circuit compares the output of the duration integration circuit with a preset judgment reference value to distinguish between noise and water leakage sound, and the output of this water leakage judgment circuit is input and the number of times a water leakage is judged is counted. , a water leakage signal storage circuit for storing, a display circuit for displaying the contents of this water leakage signal storage circuit, a first clock circuit for outputting a set signal or a reset signal at any predetermined time, and a first clock circuit for outputting a set signal or a reset signal at an arbitrary predetermined time; A first switch that increases the gain of the storage circuit that stores the signal and the reference voltage of the comparison circuit late at night when external noise has decreased; and a second switch that outputs a set or reset signal at an arbitrary predetermined time. A second clock circuit, a second memory circuit that stores the set signal and the reset signal, and a second memory circuit that turns on and off so that power is supplied to circuits with large power consumption only at midnight, based on the contents of this memory circuit. A water meter with a water leakage detection device according to claim 1, further comprising a second switching device for detecting water leakage.