Water leak detection system and ultrasonic flow meter used therein

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: The leak detection system measures ultrasonic propagation time T2 between adjacent ultrasonic flow meters 1B and 1C by using ultrasonic transceivers 6B and 6C for water flow measurement between two ultrasonic flow meters 1B and 1C connected by a pipe 15. With this, the presence or absence of water leakage in the pipe 15 can be determined by comparing the propagation time T1 when pipe 15 is leak-free.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 to detect water leaks in water supply systems such as domestic waterworks.

[0003] 2. Description of the Related Art Conventionally, a system using an ultrasonic flow meter has been known as a water leakage monitoring system for a water system (see, for example, Patent Document 1).

[0004] FIG. 4 is a schematic diagram of the water leakage monitoring system described in Patent Document 1. As shown in FIG.

[0005] In FIG. 4, the water 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. 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] For example, the first ultrasonic flowmeter 102 transmits information acquired from an ultrasonic transceiver element p1, which 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, which is received by an ultrasonic 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]

[0011] [Patent Document 1] JP 2002-131170 A Summary of the Invention [Problem to be solved by the invention]

[0012] However, in the conventional configuration, in addition to the ultrasonic flowmeters (ultrasonic flowmeters 103 and 104) installed in each residence, water supply pipes 106 and 107 branch off to detect the presence or absence of water leakage. In order to prevent this, it was necessary to provide an ultrasonic flow meter (ultrasonic flow meter 102 in the above example) on water distribution pipe 105 before the water supply.

[0013] 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.

[0014] 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]

[0015] In order to solve the above-mentioned problems, the water leak detection system of the present invention measures the propagation time T2 of ultrasonic waves between two ultrasonic flowmeters connected by a pipe through which water flows, and compares the propagation time T2 with the propagation time T1 of ultrasonic waves when there is no water leakage in the pipe to detect the presence or absence of water leakage in the pipe, thereby making it possible to determine the presence or absence of water leakage based on the propagation time measurement between adjacent ultrasonic flowmeters. Effect of the Invention

[0016] 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]

[0017] [Figure 1] FIG. 1 is a schematic configuration diagram of an ultrasonic flowmeter according to a first embodiment of the present invention. [Diagram 2] Piping system diagram according to the first embodiment of the present invention [Diagram 3] 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. [Figure 4] Schematic diagram of a conventional water leakage monitoring system DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The first invention measures the propagation time T2 of ultrasonic waves between two ultrasonic flowmeters connected by a pipe through which water flows, and compares this propagation time T2 with the propagation time T1 of ultrasonic waves when there is no water leakage in the pipe. This makes it possible to determine whether or not there is a water leak in the pipe based on the propagation time measurement between adjacent ultrasonic flowmeters, eliminating the need to install a flowmeter other than the ultrasonic flowmeter installed in each household.

[0019] The second invention, particularly in the first invention, comprises a plurality of the ultrasonic flowmeters and a center device that communicates with the ultrasonic flowmeters, the ultrasonic flowmeters having a communication unit that communicates with the center device or other ultrasonic flowmeters, and the center device uses two of the ultrasonic flowmeters to measure the propagation times T1 and T2, and determines the presence or absence of a leak in the piping based on the difference between the propagation times T1 and T2.

[0020] The third invention is an ultrasonic flowmeter for use in the water leak detection system of the first or second invention, comprising a measurement flow path through which water flows, a pair of ultrasonic transmitters and receivers arranged upstream and downstream of the measurement flow path, a flow measurement processing unit that measures the flow rate of the water using the ultrasonic transmitters and receivers, and an adjacent propagation time measurement processing unit that receives ultrasonic waves from another ultrasonic flowmeter with the ultrasonic transmitters and receivers and measures the propagation times T1 and T2.

[0021] A fourth invention is the third invention, characterized in that the adjacent propagation time measurement processing unit determines the presence or absence of a water leak in the pipe based on the difference between the propagation times T1 and T2. It is.

[0022] 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.

[0023] 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.

[0024] (Embodiment 1) FIG. 1 shows a schematic configuration diagram of an ultrasonic flowmeter 1 according to the first embodiment.

[0025] The general 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.

[0026] In the above configuration, first, when measuring the flow rate of water, the general 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.

[0027] FIG. 2 shows a piping diagram of the water leakage detection system in the first embodiment.

[0028] In FIG. 2, 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.

[0029] 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.

[0030] 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.

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

[0032] FIG. 3 is a diagram for explaining the operation between the ultrasonic flowmeters 1B and 1C in the piping system diagram shown in FIG. 2 as an example for explaining the leak detection operation. The figure shows the intake pipes 14B, 14C and the common pipe 13 that connect the above, but the intake pipes 14B, 14C and the common pipe 13 are shown as a simplified pipe 15 for the purpose of making it easier to understand the explanation of the principle of water leak detection.

[0033] In FIG. 3, the area enclosed by a dashed line indicates a water leak detection system 16, which is composed of at least two ultrasonic flowmeters as shown in the figure.

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

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

[0036] In FIG. 1, when flow rate measurement is performed, the general 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. 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.

[0038] 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.

[0039] t2 = L / (CV) (2) By eliminating the fluid sound speed C from equations (1) and (2), we obtain the following equation.

[0040] 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.

[0041] 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.

[0042] Q = k × ( V × S ) (4) In equation (4), k is a correction coefficient for correcting various errors that occur in the measurement.

[0043] In this manner, the flow rate Q can be measured using ultrasound.

[0044] 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.

[0045] Next, the water leakage detection operation of the water leakage detection system will be described with reference to FIG.

[0046] The above-mentioned flow rate measurement operation is performed separately in the ultrasonic flowmeter 1B and the ultrasonic flowmeter 1C, but in the water leakage detection operation, the ultrasonic flowmeter 1B and the ultrasonic flowmeter 1C, which are adjacently arranged via the pipe 15, perform a coordinated operation of transmitting and receiving ultrasonic waves. .

[0047] When measuring the propagation time of ultrasonic waves between adjacent ultrasonic flowmeters, the general control unit 2B of the ultrasonic flowmeter 1B first operates the communication unit 9B. The general control unit 2C of the ultrasonic flowmeter 1C also operates the communication unit 9C. Through these coordinated operations, the times of the clocks (not shown) of the ultrasonic flowmeters 1B and 1C are synchronized.

[0048] Next, the overall 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 overall control unit 2C of the ultrasonic flowmeter 1C operates the adjacent propagation time measurement processing unit 4C to start measuring the propagation time.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Now, when the flow rate of all ultrasonic flowmeters 1A, 1B, 1C, and 1D connected to the common pipe 13 in Figure 2 is zero, that is, when there is no flow in the common pipe 13 and there is no water leakage, the propagation time between the ultrasonic flowmeters 1B and 1C measured as described above is assumed to be T1.

[0053] Next, under the same conditions, if the propagation time between 1B and 1C when there is a leak in pipe 15 is taken as TL, then when there is a leak, a flow occurs in pipe 15 in the vicinity, and as a result, a difference occurs between TL and T1.

[0054] Therefore, when it is determined that there is no water leakage, such as immediately after the ultrasonic flowmeter 1C is installed, the adjacent propagation time measurement processing unit 4C measures the propagation time T1 in cooperation with the adjacent propagation time measurement processing unit 4B at the timing when it receives information that the flow rate of each of the ultrasonic flowmeters 1A, 1B, 1C, and 1D has become zero through communication with the ultrasonic flowmeters 1A, 1B, 1C, and 1D, stores the propagation time T1, and thereafter periodically measures the propagation time (T2) to obtain the difference between the propagation time T1 and the propagation time T2, and from this difference, it is possible to detect the occurrence of a water leakage in the pipe 15. That is, it is possible to detect a water leakage in the route of the lead-in pipe 14B, the common pipe 13, and the lead-in pipe 14C in FIG. 2. Then, the result of the water leakage detection is transmitted to the center device 20 via the communication unit 9C.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] Also, as shown in FIG. 2, 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.

[0059] As described above, according to this embodiment, a water leak detection system can be constructed that can detect the presence or absence of water leakage in the piping 15 by measuring the propagation time T2 of ultrasonic waves between multiple ultrasonic flowmeters connected by a piping 15 through which water flows, and comparing the propagation time T2 with the propagation time T1 of ultrasonic waves when there is no water leakage in the piping 15.

[0060] In addition, by using an ultrasonic flowmeter equipped with a pair of ultrasonic transmitters and receivers 5, 6, a flow measurement processing unit 3 that measures the water flow rate using the ultrasonic transmitters and receivers 5, 6, and an adjacent propagation time measurement processing unit 4 that receives ultrasonic waves from other ultrasonic flowmeters with the ultrasonic transmitters and receivers 5 or 6 and measures the propagation time T2, it is possible to measure the propagation time between adjacent ultrasonic flowmeters by utilizing the flow measurement configuration of the ultrasonic flowmeter, and to detect water leaks occurring between other adjacent ultrasonic flowmeters in addition to flow rate measurement.

[0061] In this example, a water leak has been described as an example, but if there is an abnormal condition that affects the propagation time, such as the inclusion of air bubbles or foreign objects, these can also be detected in the same way.

[0062] 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]

[0063] 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]

[0064] 1, 1A~1D ultrasonic flowmeter 2, 2A~2D General control unit 3. 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, 21 Water leak detection system

Claims

1. A water leak detection system that detects the presence or absence of a water leak in a pipe by measuring the propagation time T2 of ultrasonic waves between two ultrasonic flowmeters connected by a pipe through which water flows and comparing the propagation time T2 with the propagation time T1 of ultrasonic waves when there is no water leakage in the pipe.

2. The ultrasonic flowmeter includes a plurality of ultrasonic flowmeters and a center device that communicates with the ultrasonic flowmeters, The ultrasonic flowmeter includes a communication unit that communicates with the center device or other ultrasonic flowmeters, The leak detection system according to claim 1, characterized in that the center device measures the propagation times T1 and T2 using two ultrasonic flowmeters, and determines whether or not there is a leak in the piping based on the difference between the propagation times T1 and T2.

3. a measurement flow path through which water flows; A pair of ultrasonic transmitters and receivers disposed upstream and downstream of the measurement flow path; a flow rate measurement processing unit that measures a flow rate of the water using the ultrasonic transmitter and receiver; an adjacent propagation time measurement processing unit that receives ultrasonic waves from another ultrasonic flowmeter by the ultrasonic transmitter / receiver and measures the propagation times T1 and T2; 3. An ultrasonic flowmeter for use in the water leak detection system according to claim 1 or 2, comprising:

4. 4. The ultrasonic flowmeter according to claim 3, wherein the adjacent propagation time measurement processing unit determines the presence or absence of a water leak in the pipe based on a difference between the propagation times T1 and T2.

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