Water Leak Detection System

Abstract

To provide a leak detection system concerning a water supply system such as a domestic water supply having a function to detect water leakage.SOLUTION: In the leak detection system, ultrasonic flow meters 1A-1D are provided with a communication unit 9A-9D respectively and each of which cooperates with a general processing unit 58 having a general communication unit 59. When the flow rate (qi) of all the ultrasonic flow meters in a target area and the flow rate (Qi) on the upstream side of the target area are below a predetermined threshold, the ultrasonic propagation time between two adjacent ultrasonic flow meters is measured and determines the existence / absence of water leakage between adjacent flowmeters by comparing the propagation time when there is no water leakage. By performing the operation between all the ultrasonic flow meters of interest to identify the location of the leak.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a water supply system such as a domestic water supply system, and to a configuration of a water leak detection system using an ultrasonic flowmeter. [Background technology]

[0002] There is a demand for a system that detects water leakage in water supply systems such as domestic waterworks, etc. Conventionally, a system using an ultrasonic flowmeter has been known as a water leakage monitoring system for water systems (see, for example, Patent Document 1).

[0003] FIG. 6 is a schematic diagram of the water leakage monitoring system described in Patent Document 1. As shown in FIG.

[0004] In FIG. 6, the leakage monitoring system 101 has a first ultrasonic flowmeter 102, and a second ultrasonic flowmeter 103 and a second ultrasonic flowmeter 104 installed in a residence, and the first ultrasonic flowmeter 102 passes through a water distribution pipe 105, and from branch point A onwards is connected to the second ultrasonic flowmeter 103 via a water supply pipe 106, and is also connected to the second ultrasonic flowmeter 104 via a water supply pipe 107.

[0005] The first ultrasonic flowmeter 102 has a pair of ultrasonic transmitting and receiving elements p1 and p2, and measures the flow rate Q0 of water flowing through a water pipe 105 based on the propagation time based on these transmitting and receiving operations.

[0006] In addition, the second ultrasonic flowmeter 103 and the second ultrasonic flowmeter 104 also have a pair of ultrasonic transmitting / receiving elements a1, a2, and b1, b2, respectively, and are configured to measure the flow rates Qa and Qb of water flowing through the water supply pipes 106 and 107, respectively, based on the propagation time based on these transmitting and receiving operations.

[0007] With this configuration, the presence or absence of water leakage in the water distribution pipe 105 and the water supply pipes 106 and 107 can be detected by examining the difference between the values ​​of Q0 and Qa+Qb.

[0008] In this system, to obtain the flow rate difference, the flow rate information obtained by each ultrasonic flowmeter is transmitted using ultrasonic receiving and transmitting elements.

[0009] For example, the first ultrasonic flowmeter 102 transmits information acquired from an ultrasonic transceiver element p1, and the information is received by an ultrasonic transceiver element a1 of the second ultrasonic flowmeter 103. Similarly, the second ultrasonic flowmeter a103 transmits information acquired from an ultrasonic transceiver element a1, and the information is received by a transceiver element b1 of the second ultrasonic flowmeter a103. This makes it possible to transmit flow information without using wireless communication. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2002-131170 A Summary of the Invention [Problem to be solved by the invention]

[0011] However, in the conventional configuration, in order to detect the presence or absence of water leakage, in addition to the ultrasonic flowmeters (ultrasonic flowmeters 103 and 104) installed in each residence, it is necessary to install an ultrasonic flowmeter (ultrasonic flowmeter 102 in the above example) in the water distribution pipe 105 before the water supply pipes 106 and 107 branch off. there were.

[0012] In addition, although ultrasonic waves can be transmitted and received between different ultrasonic flowmeters, this only has the function of transmitting information and does not extend to the function of detecting water leaks.

[0013] The present invention is intended to solve the above-mentioned conventional problems, and aims to provide a water leak detection system that can detect the presence or absence of a water leak using only an ultrasonic flowmeter installed in a residence, without the need for a separate ultrasonic flowmeter. [Means for solving the problem]

[0014] In order to solve the above-mentioned problems, the water leakage detection system of the present invention comprises a plurality of ultrasonic flowmeters connected to a water supply network, and a control unit that controls the ultrasonic flowmeters, the ultrasonic flowmeters each comprising a pair of ultrasonic transmitters and receivers arranged in a measurement flow path, a flow rate measurement processing unit that measures a flow rate with the ultrasonic transmitters and receivers, an adjacent propagation time measurement processing unit that measures a propagation time between two adjacent ultrasonic flowmeters using the ultrasonic transmitters and receivers, a communication unit that communicates with a general communication unit, and a control unit that controls the flow rate measurement processing unit, the adjacent propagation time measurement processing unit, and the communication unit, and the control unit controls the flow rate measurement processing unit, the adjacent propagation time measurement processing unit, and the communication unit. The system is equipped with a centralized communication unit that communicates with the ultrasonic flowmeter, and a centralized processing unit that processes data from the ultrasonic flowmeter obtained via the centralized communication unit.When the flow rates of multiple ultrasonic flowmeters in a target area for water leak testing are below a predetermined threshold and the flow rate flowing into the area is below a predetermined threshold, the centralized processing unit measures all of the propagation times between two adjacent ultrasonic flowmeters of the ultrasonic flowmeters, and determines whether or not there is a leak by comparing the measured propagation time with the propagation time when there is no leak, thereby making it possible to determine whether or not there is a leak based on the propagation time measurement between adjacent ultrasonic flowmeters. Effect of the Invention

[0015] According to the water leak detection system of the present invention, the ultrasonic propagation time between two adjacent ultrasonic flowmeters connected by a pipe is measured using the respective ultrasonic transmitters used for flow measurement, and the presence or absence of a water leak can be determined by comparing the propagation time with that when there is no leak. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of a water supply network according to a first embodiment of the present invention; [Diagram 2] FIG. 1 is a schematic configuration diagram of an ultrasonic flowmeter according to a first embodiment of the present invention. [Diagram 3] FIG. 1 is a configuration diagram of a water leakage detection system according to a first embodiment of the present invention. [Figure 4]FIG. 1 is an explanatory diagram of ultrasonic signal transmission and reception between adjacent flow meters according to the first embodiment of the present invention. [Diagram 5] FIG. 1 is an explanatory diagram of an inspection procedure according to the first embodiment of the present invention. [Figure 6] Schematic diagram of a conventional water leakage monitoring system DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The first invention comprises a plurality of ultrasonic flowmeters connected to a water supply network and a control unit that controls the ultrasonic flowmeters, the ultrasonic flowmeter comprising a pair of ultrasonic transmitters and receivers arranged in a measurement flow path, a flow measurement processing unit that measures a flow rate with the ultrasonic transmitters and receivers, an adjacent propagation time measurement processing unit that uses the ultrasonic transmitters and receivers to measure a propagation time between two adjacent ultrasonic flowmeters, a communication unit that communicates with a central communication unit, and a control unit that controls the flow measurement processing unit, the adjacent propagation time measurement processing unit, and the communication unit, the control unit comprising a central communication unit that communicates with the ultrasonic flowmeters, and a central processing unit that processes data of the ultrasonic flowmeters obtained via the central communication unit, the central processing unit measures all the propagation times between two adjacent ultrasonic flowmeters of the ultrasonic flowmeters when the flow rates of the plurality of ultrasonic flowmeters in a target area for water leakage inspection are equal to or lower than a predetermined threshold value and the flow rate flowing into the area is equal to or lower than a predetermined threshold value, and determines the presence or absence of a water leak by comparing the measured propagation time with the propagation time when there is no water leakage. By performing the no-judgment method, it is possible to judge water leakage without installing any other flow meters besides the ultrasonic flow meters installed in each home.

[0018] Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or duplicate description of substantially the same configuration may be omitted.

[0019] It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0020] (Embodiment 1) FIG. 1 is a schematic configuration diagram of a water supply network in accordance with a first embodiment of the present invention.

[0021] In Fig. 1, the area surrounded by a dashed line is a water supply network 60, in which water is supplied from a water supply plant 51 via a main pipe 52, a branch section 53, a common pipe 54, and an inlet pipe 55 to individual houses 56 (A, B, C, D). Each house 56 is equipped with an ultrasonic flowmeter (not shown). For convenience of explanation, the area in which the houses 56 (A, B, C, D) are located is defined as a target area 57 for leak inspection. Furthermore, as shown in Fig. 1, each house 56 is in an area that includes the end E of the common pipe 54.

[0022] The central device 20 has a general processing unit 58 arranged therein, which issues instructions through a general communication unit 59 to a communication unit (not shown) of an ultrasonic flow meter (not shown) in each of the houses 56 in the target area 57. The central device 20 may be installed in the water supply plant 51, and the installation location is not particularly limited.

[0023] FIG. 2 shows a schematic configuration diagram of the ultrasonic flowmeter 1 according to the first embodiment.

[0024] The control unit 2 controls the flow rate measurement processing unit 3 and the adjacent propagation time measurement processing unit 4. The measurement flow path 10 is a water passage provided inside the ultrasonic flowmeter 1, and ultrasonic transmitters and receivers 5 and 6 are arranged on the upstream and downstream outer peripheries. In addition, ultrasonic reflectors 7 and 8 are arranged in the center of the measurement flow path 10 to reflect ultrasonic waves emitted from the ultrasonic transmitters and receivers 5 and 6 in a 90° direction. In addition, the communication unit 9 transmits and receives various data by communicating with the outside. In addition, the arrow 11 indicates the direction in which the water flows. The dashed line 12 indicates the propagation path of the ultrasonic waves. The ultrasonic transmitters and receivers 5 and 6 are fixed to the measurement flow path 10 by a fixing member not shown.

[0025] In the above configuration, when measuring the flow rate of water, first, the control unit 2 operates the flow rate measurement processing unit 3 to apply a pulse wave to the ultrasonic transmitter / receiver 5 and emit ultrasonic waves. The emitted ultrasonic waves propagate along the dashed line 12, pass through the ultrasonic reflectors 7 and 8, and reach the ultrasonic transmitter / receiver 6. The flow rate measurement processing unit 3 measures the propagation time from transmission to reception of the ultrasonic waves. Similarly, the propagation time of the ultrasonic waves in the reverse direction, i.e., from the ultrasonic transmitter / receiver 6 to the ultrasonic transmitter / receiver 5, is measured.

[0026] FIG. 3 is a configuration diagram of the water leakage detection system in the first embodiment, showing the connection state between the ultrasonic flowmeters 1A, 1B, 1C, and 1D installed in each house 56 in the target district 57 and the common pipe 13.

[0027] In FIG. 3, ultrasonic flowmeters 1A, 1B, 1C, and 1D are connected from the upstream side to the downstream side of a common pipe 13 via lead-in pipes 14A, 14B, 14C, and 14D, respectively.

[0028] In this embodiment, a configuration in which four ultrasonic flowmeters (ultrasonic flowmeters 1A, 1B, 1C, and 1D) are connected to common pipe 13 will be described as an example, but the number of ultrasonic flowmeters is not limited to this.

[0029] The center device 20 also has a function of receiving meter reading data such as measured flow rates and issuing various instructions to the ultrasonic flowmeters by communicating with the ultrasonic flowmeters 1A, 1B, 1C, and 1D. The method of communication with each ultrasonic flowmeter is not particularly limited, and may be cellular communication, specific low-power wireless communication, or a network via a relay station.

[0030] The above-mentioned elements together constitute the water leak detection system 21.

[0031] Fig. 4 is a diagram for explaining ultrasonic transmission and reception between adjacent ultrasonic flowmeters in embodiment 1. In Fig. 3 and Fig. 4, the same numbers are used for components having the same functions as those in Fig. 2, and the symbols A, B, C, and D added after the numbers indicate the correspondence with the ultrasonic flowmeters 1A, 1B, 1C, and 1D, respectively, and are omitted unless a distinction is particularly necessary.

[0032] FIG. 4 is a diagram for explaining the operation between ultrasonic flowmeters 1B and 1C in the piping system diagram shown in FIG. 3 as an example for explaining the leak detection operation, and shows the ultrasonic flowmeters 1B and 1C and the inlet pipes 14B and 14C and common pipe 13 that connect them. However, the inlet pipes 14B and 14C and common pipe 13 are shown as simplified pipe 15 for the convenience of easily explaining the principle of leak detection.

[0033] In FIG. 4, the area enclosed by a dashed line indicates a water leak detection configuration 16, which is composed of at least two ultrasonic flowmeters as shown in the figure.

[0034] Next, the operation of this water leakage detection structure 16 will be described with reference to FIGS.

[0035] First, the flow rate measurement will be described with reference to FIG.

[0036] In FIG. 2, when flow rate measurement is performed, the control unit 2 starts a flow rate measurement operation by the flow rate measurement processing unit 3.

[0037] Now, the flow velocity of the fluid flowing in the direction of the arrow inside measurement flow path 10 is denoted as V, and the sound speed in the fluid is denoted as C. The length of the straight portion of the propagation path of the ultrasonic wave propagating between ultrasonic transmitter / receiver 5 and ultrasonic transmitter / receiver 6 is denoted as L.

[0038] At this time, the propagation time t1 that the ultrasonic wave emitted from the ultrasonic transmitter / receiver 5 takes to travel along L until it reaches the other ultrasonic transmitter / receiver 6 is expressed by the following formula.

[0039] t1 = L / (C+V) (1) Next, the propagation time t2 that the ultrasonic wave emitted from the ultrasonic transmitter / receiver 6 takes to travel along L until it reaches the other ultrasonic transmitter / receiver 5 is expressed by the following formula.

[0040] t2 = L / (CV) (2) By eliminating the fluid sound speed C from equations (1) and (2), we obtain the following equation.

[0041] V = L / 2((1 / t1)-(1 / t2)) (3) As can be seen from equation (3), if L is known, the flow velocity V can be calculated using the measured propagation times t1 and t2.

[0042] Next, the flow rate Q can be calculated by multiplying the flow velocity V by the cross-sectional area S of the measurement flow path 10 as shown in the following formula.

[0043] Q = k × ( V × S ) (4) In equation (4), k is a correction coefficient for correcting various errors that occur in the measurement.

[0044] In this manner, the flow rate Q can be measured using ultrasound.

[0045] Here, the propagation time between the ultrasonic transmitter / receiver 5 and the ultrasonic transmitter / receiver 6 includes the propagation time between the ultrasonic transmitter / receiver 5 and the ultrasonic reflector 7, and between the ultrasonic transmitter / receiver 6 and the ultrasonic reflector 8. Since these propagation times are basically independent of the flow velocity and can be calculated, by correcting these values, it is possible to determine only the propagation time of the portion of the above propagation path of length L.

[0046] Next, the water leakage detection operation in the water leakage detection configuration 16 will be described with reference to FIG.

[0047] The above-mentioned flow rate measurement operation is performed separately in ultrasonic flowmeter 1B and ultrasonic flowmeter 1C, but in the leak detection operation, ultrasonic waves are transmitted and received in a coordinated manner between ultrasonic flowmeter 1B and ultrasonic flowmeter 1C, which are arranged adjacent to each other via piping 15.

[0048] When measuring the propagation time of ultrasonic waves between adjacent ultrasonic flowmeters, first, the control unit 2B of the ultrasonic flowmeter 1B operates the communication unit 9B. Also, the control unit 2C of the ultrasonic flowmeter 1C operates the communication unit 9C. Through these linked operations, the times of the clocks (not shown) of the ultrasonic flowmeters 1B and 1C are synchronized.

[0049] Next, the control unit 2B of the ultrasonic flowmeter 1B operates the adjacent propagation time measurement processing unit 4B to transmit an ultrasonic signal, and at the same time, the control unit 2C of the ultrasonic flowmeter 1C operates the adjacent propagation time measurement processing unit 4C to start measuring the propagation time.

[0050] The ultrasonic waves emitted from the ultrasonic transmitter / receiver 6B of the ultrasonic flowmeter 1B are reflected by the ultrasonic reflector 8B and propagate toward the ultrasonic reflector 7B. At this time, a part of the propagating ultrasonic waves is reflected by the ultrasonic reflector 7B and travels toward the pipe wall, while a part of the propagating ultrasonic waves propagates throughout the entire pipe.

[0051] The ultrasonic waves that spread within the pipe travel through piping 15 (actually, inlet pipe 14B, common piping 13, inlet pipe 14C), are reflected by ultrasonic reflector 8C of ultrasonic flowmeter 1C, and are received by ultrasonic transmitter / receiver 6C, and the received waveform is measured by adjacent propagation time measurement processing unit 4C.

[0052] As mentioned earlier, the clock times of the ultrasonic flowmeters 1B and 1C are the same, so by starting transmission and measuring the propagation time at the same time, it is possible to measure the propagation time between adjacent ultrasonic flowmeters, from when a signal is emitted from the ultrasonic transmitter / receiver 6B of the ultrasonic flowmeter 1B to when it is received by the ultrasonic transmitter / receiver 6C of the ultrasonic flowmeter 1C.

[0053] Using this measurement method, if the propagation times T1 and TL are taken as the propagation times when there is no leakage and when there is leakage in the pipe 15, respectively, a difference in the propagation times will occur. The presence or absence of leakage between the ultrasonic flowmeters 1B and 1C can be detected based on this difference in the propagation times.

[0054] The propagation time T1 when there is no leakage is the time when it is judged that there is no leakage, such as when the ultrasonic flowmeter is installed. This should be requested in case the request is rejected.

[0055] Next, a method for checking the presence or absence of water leakage in the target area 57 will be described with reference to FIG.

[0056] 3, branch points from the common pipe 13 to the inlet pipes 14A to 14D leading to the ultrasonic flowmeters 1A to 1D are designated as P1 to P3. The pipe path from the ultrasonic flowmeter 1A to 1B is designated as Lab, the pipe path from the ultrasonic flowmeter 1B to 1C is designated as Lbc, and the pipe path from the ultrasonic flowmeter 1C to 1D is designated as Lcd.

[0057] The flow rates through the inlet pipes 14A to 14D are respectively q1 to q4. The flow rate at the branch point P1 of the common pipe 13 is Q1. That is, Q1 is the sum of the flow rates of the ultrasonic flowmeters 1A to 1D. Thereafter, the flow rates at points P2, P3, and P4 are respectively Q2 to Q4. Note that, since the inlet pipe 14D is located at the end E of the common pipe 54, q4=Q4.

[0058] The pipe cross-sectional areas of the lead-in pipes 14A to 14D are denoted by s1 to s4, respectively. The cross-sectional areas of the common pipe 13 are denoted by S1 to S3 for the sections P1-P2, P2-P3, and P3-P4, respectively.

[0059] First, let us consider the detection of water leakage in the path Lbc described as an example in FIG.

[0060] The path of Lbc is composed of the inlet pipe 14B, the P2-P3 portion of the common pipe 13 (this portion is designated as L2), and the inlet pipe 14C. The flow rates through these pipes are q2, Q2, and q3, as described above, respectively. In addition, their cross-sectional areas are s2, S2, and s3, respectively.

[0061] When conducting a leak test, it would be convenient if all of these flow rates were zero, but in reality, they are not always zero. Therefore, we will consider conditions that allow judgment even if there is some flow.

[0062] The physical quantity used to determine the leak is the propagation time. Here, the propagation time when there is no flow is used as the standard, and the standard propagation time is basically the value obtained by dividing the target pipe length by the speed of sound.

[0063] When actually detecting a leak, if there is a flow in the pipe other than the flow caused by the leak, it will become an error factor. The error factor is the flow velocity added to the sound speed in the propagation time calculation. Therefore, the ratio of this flow velocity to the sound speed can be used as an error index.

[0064] Here, the ratio of these flow velocities to the speed of sound is taken as the speed of sound ratio, and the level of error can be determined by setting a threshold value r for that value. For example, the value of threshold value r can be set to 1% of the speed of sound. The value of this threshold value r is related to the level at which leak detection is performed. In other words, to raise the detection level, the value of threshold value r should be reduced.

[0065] Specifically, the piping path Lbc is as follows. If the flow velocities in the inlet pipe 14B, L2 of the common pipe 13, and the inlet pipe 14C are v2, V2, and v3, respectively, then the respective values ​​can be found by dividing the respective flow rates q2, Q2, and q3 by their cross-sectional areas s2, S2, and s3. If the values ​​obtained by dividing these values ​​by the speed of sound are m2, M2, and m3, these become the sound speed ratios. By comparing this value with the threshold value r, it is possible to determine whether or not a leak can be detected.

[0066] In this way, by setting the error level using the sound speed ratio, it is possible to determine the presence or absence of a leak based on a comparison of the propagation time measured in the piping path Lbc with the propagation time when there is no leak, even if there is some flow.

[0067] In the above, the sound velocity ratio is used as a threshold value to explain the physical meaning of the error, but since the sound velocity of the fluid for calculating the sound velocity ratio is constant and the cross-sectional area of ​​the pipe is constant at each location, the flow velocity of each fluid may be replaced with the flow rate of the fluid. In other words, the sound velocity ratio as a threshold value can actually be considered as the flow rates q2, Q2, and q3 measured by the ultrasonic flowmeter. In other words, the level of the error can be determined by comparing the flow rates in each flow path with a preset flow rate threshold value.

[0068] The above describes the operation for the piping route Lbc in Figure 3, but by performing the same operation for the piping routes Lab and Lcd, it is possible to determine whether there is a leak in the target area 57 and the location of the leak along which route it is occurring.

[0069] The level of error can be determined by the flow rate qi (i = 1 to 4) of the inlet pipe and the flow rate Qi (i = 1 to 3) of the common pipe.

[0070] In this example, in order to easily explain the mechanism of leak detection, the target area 57 is an area that includes the end of the common pipe 13, but the same concept can be applied to an intermediate area that does not include the end.

[0071] In addition, since the common pipe 13 usually has a constant cross-sectional area and its flow rate decreases downstream, it is acceptable to use the value of the flow rate at the upstream end P1 of the target area 57, i.e., the flow rate flowing into this target area 57, to determine the flow rate of the common pipe 13.

[0072] FIG. 5 is a flowchart of the detection operation of this water leakage detection system.

[0073] The process shown in this flowchart is performed by the overall processing unit 58 shown in FIG.

[0074] In FIG. 5, step S1 is a command to start measurement, and step S2 is a command to instruct each ultrasonic flowmeter to measure flow rates. Step S3 is a flow rate measurement subroutine for each ultrasonic flowmeter. Step S4 is a command to obtain the measurement data obtained in subroutine S3. Step S5 is a command to process the measurement data obtained in measurement data obtainment command S4. Step S6 is a command to determine whether the flow rates of all ultrasonic flowmeters and the inlet flow rate of the target area are below a predetermined threshold value.

[0075] Step S7 is a command to measure the propagation time between two ultrasonic flowmeters. Step S8 is a subroutine to measure the propagation time between the ultrasonic flowmeters. Step S9 is a command to obtain the measurement data obtained in the subroutine S8. Step S10 is a command to process the measurement data obtained in the measurement data obtain command S9.

[0076] Step S11 is a command to determine whether or not there is a leak. Step S12 is a command to generate an alarm. Step S13 is a command to end the process. Steps S14 and S15 are commands to set an interval.

[0077] Next, the actual water leakage detection operation will be described with reference to FIG. 3 and FIG.

[0078] As shown in FIG. 3, the central processing unit 58 exchanges various instructions and information with the communication units 9A, 9B, 9C, and 9D attached to the ultrasonic flowmeters 1A, 1B, 1C, and 1D via the central communication unit 59.

[0079] The operation sequence is explained with reference to FIG.

[0080] First, a measurement operation is started by a start command (step S1).

[0081] Next, a flow measurement instruction command (step S2) executes a flow measurement subroutine (step S3) for each ultrasonic flowmeter 1A, 1B, 1C, and 1D, and the flow rates of each ultrasonic flowmeter 1A, 1B, 1C, and 1D are measured. Next, a measurement data acquisition command (step S4) causes the flow data of each ultrasonic flowmeter 1A, 1B, 1C, and 1D to be collected in the general processing unit 58 via the general communication unit 59.

[0082] Next, a processing command (step S5) is issued to determine the flow rates qi (i=1 to 4) of each inlet pipe, that is, the flow rates Qi (i=1 to 3) of each branch point of the common pipe 13 based on the flow rate data of each ultrasonic flowmeter 1A, 1B, 1C, and 1D.

[0083] The flow rates qi, Qi are compared with predetermined threshold values ​​q, Q that are determined in advance based on the level of an allowable error by a decision command (step S6), and if both are below the threshold values, Yes is selected.

[0084] Next, a command to measure the propagation time between the two ultrasonic flowmeters (step S7) is executed, which causes a subroutine to measure the propagation time between the two ultrasonic flowmeters of each of the ultrasonic flowmeters 1A, 1B, 1C, and 1D (step S8) to be executed, and the propagation time between each ultrasonic flowmeter is measured according to a predetermined sequence.

[0085] An example of the sequence of the leak detection is as follows: (1) Measure the ultrasonic propagation time (Tab) between ultrasonic flowmeters 1A and 1B (piping path Lab). (2) Measure the ultrasonic propagation time (Tbc) between ultrasonic flowmeters 1B and 1C (piping path Lbc). (3) Measure the ultrasonic propagation time (Tcd) between ultrasonic flowmeters 1C and 1D (piping path Lcd). Next, in response to a measurement data acquisition command (step S9), these data (Tab, Tbc, Tcd) are collected in the overall processing unit 58.

[0086] This data is compared with the pre-recorded inter-flowmeter propagation times T0ab, T0bc, and T0cd when there is no leakage by a processing command (step S10) to determine whether there is leakage or not, and if there is leakage, the location is identified. In the judgment command (step S11), if there is leakage as a result of the processing command (step S10), Yes is selected, a leakage alarm is issued by an alarm command (step S12), and the process is terminated by an end command (step S13). If there is no leakage, the No side is selected, and after a predetermined interval command (step S14), the same operation is repeated to continue monitoring for leakage.

[0087] If the conditions are not met in the previous judgment command (step S6), No is selected, and after the interval setting command (step S15), the operations following the flow rate measurement command (step S2) are repeated.

[0088] In the above explanation, ultrasonic waves were emitted from ultrasonic flowmeter 1B and the propagation time until they reached ultrasonic flowmeter 1C was measured, but the same effect can be achieved by measuring the propagation time from ultrasonic flowmeter 1C to ultrasonic flowmeter 1B in the opposite manner.

[0089] In the above embodiment, the determination was made between ultrasonic flowmeter 1B and ultrasonic flowmeter 1C, but a similar leak detection can be performed by selecting any two of ultrasonic flowmeters 1A, 1B, 1C, and 1D.

[0090] Furthermore, the adjustment of the time of the clocks between the ultrasonic flowmeters is not limited to the communication between each other, and may be performed by communicating with the center device 20 to match the time of the clock held by the center device 20, and is not particularly limited.

[0091] Also, as shown in FIG. 3, a water leak detection system 21 may be configured to include a center device 20 and a plurality of ultrasonic flowmeters. When it is necessary to detect a water leak, the center device 20 may select two ultrasonic flowmeters (e.g., ultrasonic flowmeters 1A and 1B) connected to the target pipe, instruct the adjacent propagation time measurement processing units 4 to measure propagation times T1 and T2, and the center device 20 may acquire these propagation times T1 and T2 and determine whether or not there is a water leak.

[0092] Also, although the control unit has been described as a central device, the control unit function may be provided in one of the ultrasonic flowmeters installed in the target area.

[0093] As described above, according to this embodiment, the ultrasonic flowmeter 1 includes a plurality of ultrasonic flowmeters 1 connected to a water supply network 60 and a control unit 20 that controls the plurality of ultrasonic flowmeters 1. The ultrasonic flowmeter 1 includes a pair of ultrasonic transmitters and receivers 5 and 6 arranged in a measurement flow path 10, a flow rate measurement processing unit 3 that measures a flow rate with the ultrasonic transmitters and receivers 5 and 6, an adjacent propagation time measurement processing unit 4 that measures a propagation time between two adjacent ultrasonic flowmeters using the ultrasonic transmitters and receivers 5 and 6, a communication unit 9 that communicates with a general communication unit 59, and a control unit 2 that controls the flow rate measurement processing unit 3, the adjacent propagation time measurement processing unit 4, and the communication unit 9. The control unit 20 includes a control communication unit 59 that communicates with multiple ultrasonic flowmeters 1, and a control processing unit 58 that processes data on multiple ultrasonic flowmeters 1 obtained via the control communication unit 59. When the flow rate of each ultrasonic flowmeter 1A-1C in the target area 57 for leak testing is below a predetermined threshold and the flow rate flowing into the target area 57 is below a predetermined threshold, the control processing unit 58 measures all of the propagation times between two adjacent ultrasonic flowmeters of the ultrasonic flowmeters 1A-1C, and compares the measured propagation time with the propagation time when there is no leakage to determine whether there is a leakage or not.

[0094] In this example, a water leak has been described as an example, but any abnormal condition that affects the propagation time, such as the inclusion of air bubbles or foreign objects, can also be detected in a similar manner.

[0095] In the above explanation, the change in the propagation time was examined, but it is also possible to examine the change in the peak value of the received wave. This is particularly effective because air bubbles and foreign matter are more likely to appear in the change in peak value than in the propagation time. [Industrial Applicability]

[0096] As described above, the water leak detection system of the present invention can determine the presence or absence of a water leak based on the ultrasonic propagation time between adjacent ultrasonic flowmeters, making it possible to apply the system to a wide range of applications, such as domestic water supply piping systems and heating / cooling aqueduct piping systems that use hot and cold water. [Explanation of symbols]

[0097] 1, 1A~1D ultrasonic flow meter 2, 2A~2D control section 3, 3A~3D Flow measurement processing section 4, 4A~4D Adjacent propagation time measurement processing section 5, 5A~5D Ultrasonic transmitter / receiver 6, 6A~6D Ultrasonic transmitter / receiver 9, 9A~9D Communication Department 10 Measurement flow path 15 Piping 16 Leak detection configuration 20 Central Equipment (Control Department) 21 Water Leak Detection System

Claims

[Claim 1] The present invention comprises a plurality of ultrasonic flowmeters connected to a water supply network, and a control unit that controls the ultrasonic flowmeters, The ultrasonic flow meter includes: A pair of ultrasonic transmitters and receivers disposed in the measurement flow path; a flow rate measurement processing unit that measures a flow rate by the ultrasonic transmitter / receiver; an adjacent propagation time measurement processing unit that measures a propagation time of an ultrasonic wave between two adjacent ultrasonic flowmeters using the ultrasonic transmitter and receiver; a communication department that communicates with the general communication department; a control unit that controls the flow rate measurement processing unit, the adjacent propagation time measurement processing unit, and the communication unit; The said control department: A general communication unit that communicates with the ultrasonic flowmeter; a central processing unit that processes data of the ultrasonic flowmeter obtained via the central communication unit, The integrated processing unit is a leak detection system that measures all of the ultrasonic propagation times between two adjacent ultrasonic flowmeters of the ultrasonic flowmeters when all of the flow rates of the multiple ultrasonic flowmeters in the area subject to leak testing are below a predetermined threshold and when the flow rates between two adjacent ultrasonic flowmeters measured in conjunction with the multiple ultrasonic flowmeters in the area are all below a predetermined threshold, and determines whether or not there is a leak by comparing the measured propagation times with the propagation times when there is no leak.

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