Water leakage detection system

Abstract

To provide a water leakage detection system capable of easily detecting a water leakage location in a water pipe buried in the ground.SOLUTION: There is provided a water leak detection system 1 which includes a plurality of RFID tags 10-1, 10-2, 10-3, ..., 10-n buried along a water pipe 3 buried in the ground 5, an RFID reader / writer 20 to which an antenna 6 that communicates with the plurality of RFID tags 10-1, 10-2, 10-3, ..., 10-n is connected, and a control device 30 connected to the RFID reader / writer 20. The plurality of RFID tags 10-1, 10-2, 10-3, ..., 10-n are buried in the ground 5 consecutively at a predetermined interval S1 along the water pipe 3. The control device 30 detects a location where water has leaked from the water pipe 3 based on signals transmitted from the plurality of RFID tags 10-1, 10-2, 10-3, ..., 10-n to the RFID reader / writer 20.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a water leakage detection system.

Background Art

[0002] Currently, when repairing water leakage in water pipes such as water supply pipes and drainage pipes, a water pipe repairer inserts a detection rod (also called a "listening rod") equipped with a sound sensor and a vibration sensor into the ground where the water pipe is buried, for example, to detect the water leakage sound and vibration caused by water leakage and identify the location of the water leakage.

[0003] For example, there is disclosed a water leakage detection method using an RFID tag installed near a joint of a water distribution pipe and an RFID reader / writer that communicates with the RFID tag, which detects water leakage based on a change in the communication state due to water leakage flowing from the joint of the water distribution pipe into the RFID tag (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional method of identifying water leakage points using a detection rod, if it was impossible to identify the water leakage point of a water pipe buried underground by relying on faint water leakage sounds or vibrations and digging up the soil at the suspected location, and then repeating the operation of detecting the water leakage sound or vibration at the next location, it was necessary to identify the water leakage point. Therefore, even for a water pipe about 15 m long, it took 1 to 2 hours to find the water leakage point in the ground using a detection rod, and it was necessary to perform heavy labor of digging up the soil many times before reaching the water leakage point. Also, some repair workers were unable to identify the water leakage point and even gave up.

[0006] Furthermore, in the conventional water leakage detection method described in the prior art documents, although it was possible to detect water leakage at specific joints of the water distribution pipe, it was impossible to easily detect the water leakage point of a water pipe buried underground.

[0007] In view of the above problems, an object of the present invention is to provide a water leakage detection system capable of easily detecting the water leakage point of a water pipe buried underground.

Means for Solving the Problems

[0008] To achieve the above object, the water leakage detection system of the present invention is a water leakage detection system including a plurality of RFID tags buried along a water pipe buried underground, an RFID reader / writer connected to an antenna that communicates with the plurality of RFID tags, and a control device connected to the RFID reader / writer. The plurality of RFID tags are continuously buried in the ground at a predetermined interval along the water pipe, and the control device is characterized by detecting the location where the water pipe has leaked based on the signals transmitted from the plurality of RFID tags to the RFID reader / writer.

[0009] Also, the plurality of RFID tags may be continuously buried in parallel with the water pipe.

[0010] Further, the plurality of RFID tags may be enclosed in a long tape and continuously embedded at the predetermined intervals.

[0011] Further, the antenna may be formed in a cable shape and embedded along the water pipe.

[0012] Further, the plurality of RFID tags are continuously assigned with EPCs capable of identifying each RFID tag, and the control device may detect a location where the water pipe has leaked based on the EPCs included in the signals received from the plurality of RFID tags continuously embedded along the water pipe.

Advantages of the Invention

[0013] According to the present invention, it is possible to easily detect a location where a water pipe buried underground has leaked.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present embodiment will be described with reference to the drawings. Note that multiple embodiments can be combined and implemented within a non - conflicting range.

[0016] A water leakage detection system according to this embodiment will be described. FIG. 1 is a diagram showing a state in which no water leakage has occurred in an example of the water leakage detection system 1 according to this embodiment. FIG. 2 is a diagram showing a state in which water leakage has occurred in an example of the water leakage detection system 1 according to this embodiment. The water leakage detection system 1 is used to detect a water leakage location X of water leaking from a water pipe 3 buried in the ground 5.

[0017] In the embodiment shown in FIG. 1, the water pipe 3 is buried and used in a substantially horizontal direction in the ground 5. The water pipe 3 may be buried and used while being curved in the ground 5. The water pipe 3 is used as a water supply pipe or a drain pipe for water supply and drainage of water. The water pipe 3 may be a pipe for supplying and draining liquids other than water. The water pipe 3 is formed of a polyvinyl chloride resin. The water pipe 3 may be formed of a resin such as polyethylene or polypropylene. The water pipe 3 may be formed of a metal such as copper, iron, stainless steel, or galvanized steel.

[0018] In this embodiment, the ground 5 indicates a region located below the surface of the ground surface 7 and is mainly composed of soil. The ground 5 is not limited to soil and may be composed of sand (earth and sand), concrete, asphalt, etc. or a mixture thereof.

[0019] The water leakage detection system 1 includes a plurality of RFID tags 10-1, 10-2, 10-3 ···, 10-n (n is a natural number of 2 or more), an RFID reader / writer 20, and a control device 30. When the RFID tags 10-1, 10-2, 10-3 ···, 10-n are not particularly distinguished and described, they are hereinafter referred to as "RFID tag 10".

[0020] The RFID tag 10 stores an EPC (Electronic Product Code) for uniquely identifying each RFID tag 10-1, 10-2, 10-3 ···, 10-n in a memory chip. In the present embodiment, the last digit of the EPC in each RFID tag 10-1, 10-2, 10-3 ···, 10-n is used as a serial number. For this reason, in the present embodiment, the RFID tag 10 is used in which the last digits of the EPCs of adjacent RFID tags 10-1, 10-2, 10-3 ···, 10-n are consecutive numbers. In the present embodiment, for example, the last digits of the EPCs in each RFID tag 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, 10-8, 10-9 ···, 10-n are set as consecutive numbers "00001", "00002", "00003", "00004", "00005", "00006", "00007", "00008", "00009" ···, "0000n" as shown in FIG. 1. In the present embodiment, the last digit of the EPC in each RFID tag 10-1, 10-2, 10-3 ···, 10-n is used as a serial number, but this is not the only case. For example, any digit or alphabet of the EPC in each RFID tag 10-1, 10-2, 10-3 ···, 10-n may be used as a serial number. Also, in the present embodiment, the last digit of the EPC in each RFID tag 10-1, 10-2, 10-3 ···, 10-n is used as a serial number, but this is not the only case. Instead of the EPC, the last digit of the UID (Unique Identifier) stored in the memory chip of each RFID tag 10-1, 10-2, 10-3 ···, 10-n or alphanumeric characters of a predetermined number of digits may be used as a serial number. The serial number functions as an identification symbol that can uniquely identify each RFID tag 10-1, 10-2, 10-3 ···, 10-n.

[0021] Each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n may be encapsulated in a long encapsulation tape 4 having waterproof and corrosion-resistant properties. The length dimension of the encapsulation tape 4 is formed to be approximately the same as the length of the water pipe 3. The length dimension of the encapsulation tape 4 can be selected arbitrarily based on the length of the water pipe 3. The encapsulation tape 4 may be formed of a resin such as polyester, polyvinyl chloride, polypropylene, polyimide, polyethylene, or a rubber such as natural rubber or synthetic rubber. By encapsulating the RFID tag 10 in the encapsulation tape 4, even if the RFID tag 10 is buried in the ground 5 for a long time, it can withstand water damage and corrosion to the components such as the substrate and antenna constituting the RFID tag 10. As a result, it is possible to provide for a long time a function of transmitting a signal of information including the EPC of the RFID tag 10 itself to the RFID reader / writer 20 in response to a signal transmitted from the antenna 6 of the RFID reader / writer 20. Further, by previously encapsulating each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n in the encapsulation tape 4 and burying the encapsulation tape 4 in which the RFID tag 10 is encapsulated in the ground 5, it is possible to construct the water leakage detection system 1 more quickly than burying each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n in the ground 5 one by one. When the water pipe 3 is buried in a curved shape in the ground 5, the encapsulation tape 4 in which each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n is encapsulated can be buried in a curved shape following the shape of the curved water pipe 3. Thereby, regardless of the shape of the water pipe 3, it is possible to easily construct the water leakage detection system 1 for detecting the water leakage location of the water pipe 3.

[0022] The RFID reader / writer 20 measures the RSSI value (radio wave intensity) of the return signal from the RFID tag 10 for each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n. The RSSI value is a value indicating the intensity of the signal of the RFID tag 10 received by the RFID reader / writer 20.

[0023] Moisture has the characteristic of being likely to absorb electromagnetic waves, especially those in the UHF (Ultra High Frequency) and HF (High Frequency) bands used between the electromagnetic wave reader / writer 20 and the RFID tag 10. For this reason, when there is a large amount of moisture around the RFID tag 10, the RSSI value measured by the RFID reader / writer 20 tends to be lower compared to when there is less moisture around the RFID tag 10. This is because it inhibits the propagation of electromagnetic waves and attenuates the intensity of the signal transmitted by the RFID tag 10. That is, the signal with the wavelength transmitted from the RFID tag 10 has less attenuation in the dry soil 5-1, but has greater attenuation in the soil 5-2 containing moisture due to the water 8 generated by the water leakage of the water pipe 3. When the signal transmitted from the RFID tag 10 is in the UHF band, the attenuation due to the presence of moisture becomes even more prominent.

[0024] When the water pipe 3 is damaged due to aging and water leakage occurs, the moisture content of the soil 5-2 near the location of the water leakage increases. As a result, the reading distance of the signal transmitted from the RFID tag 10 buried near the location of the water leakage is significantly shortened when received by the RFID reader / writer 20.

[0025] After each of the RFID tags 10-1, 10-2, 10-3···, 10-n is buried in the ground 5, in order to be able to recognize the locations where each of the RFID tags 10-1, 10-2, 10-3···, 10-n is buried, among each of the buried RFID tags 10-1, 10-2, 10-3···, 10-n, a label or seal stating the end of the EPC of the first RFID tag 10-1 and the end of the EPC of the last RFID tag 10-n is attached to the water supply equipment connected to the water pipe 3. As the water supply equipment, a water meter box can be used. The water supply equipment is not limited to the water meter box, and it may also be a water heater, a faucet, a water purification device, etc.

[0026] In this embodiment, the RFID tag 10 is designed to be fully readable even when it is buried in the soil 5-1 on a sunny day and read by the RFID reader / writer 20 from the ground surface 7. To achieve a readable design, for example, elements such as the frequency band to be used, the transmission output of the signal of the RFID reader / writer 20, the design of the antenna of the RFID tag 10, and the orientation of the RFID tag 10 can be adjusted by arbitrarily setting them. The control device 30 determines a threshold value based on the RSSI value when reading is performed by the RFID reader / writer 20 from the ground surface 7 in a state where the RFID tag 10 is buried in the soil 5-1 on a sunny day. The control device 30 stores the determined threshold value in a storage unit 32 described later. The threshold value is an index for detecting whether water leakage has occurred near the RFID tag 10. The threshold value may be set in advance at the time of product shipment.

[0027] By moving the RFID reader / writer 20 on the ground surface 7 along each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n buried along the water pipe 3, the RFID reader / writer 20 transmits signals to each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n respectively.

[0028] When no water leakage occurs in the water pipe 3, as shown in FIG. 1, the RFID reader / writer 20 can receive all the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n. The RFID reader / writer 20 transmits the signals received from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n to the control device 30 together with the RSSI values of each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n. When no water leakage occurs in the water pipe 3, the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n include "00001", "00002", "00003", "00004", "00005", "00006", "00007", "00008", "00009" ···, "0000n" as the information at the end of the EPC.

[0029] When water leakage occurs in the water pipe 3, the response signal responded from the RFID tag 10-5 embedded in the soil 5-2 near the water leakage point X is such that the propagation of the electromagnetic wave is inhibited due to the presence of moisture, and the intensity of the signal transmitted by the RFID tag 10-5 is attenuated. As a result, when water leakage occurs in the water pipe 3, as shown in Fig. 2, the RFID reader / writer 20 receives only the response signals responded from the RFID tags 10 other than the RFID tag 10-5 embedded in the soil 5-2 near the water leakage point X among the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n.

[0030] The RFID reader / writer 20 transmits the response signals responded from the RFID tags 10 other than the RFID tag 10-5 among each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n to the control device 30. When water leakage occurs in the water pipe 3, the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n include "00001", "00002", "00003", "00004", "00006", "00007", "00008", "00009", ···, "0000n" as the information at the end of the EPC. That is, the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n do not include the information "00005" at the end of the EPC corresponding to the RFID tag 10-5.

[0031] Also, as shown in Fig. 2, in this embodiment, since a part of the soil 5-2 near the water leakage point X overlaps with the RFID tag 10-6, the responded response signal is affected by attenuation due to moisture. Therefore, the RSSI value of the response signal responded from the RFID tag 10-6 will be lower than the RSSI values of the response signals responded from the other RFID tags 10-1, 10-2, 10-3 ···, 10-n.

[0032] The RFID reader / writer 20 transmits the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n including the RFID tag 10-6 affected by the soil 5-2 near the water leakage location X to the control device 30. The RSSI values of the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n are linked and transmitted along with the response signals responded from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n.

[0033] The RFID reader / writer 20 and the control device 30 are connected by wireless communication or wired communication. As wireless communication, Bluetooth (registered trademark), wireless LAN, mobile phone network (GSM, CDMA, LTE, 5G), etc. can be used. As wired communication, wired LAN, coaxial cable, optical fiber, telephone line (DSL, ADSL), USB (Universal Serial Bus), etc. can be used.

[0034] The control device 30 detects the location where the water pipe 3 has a water leakage based on the response signals transmitted from the plurality of RFID tags 10-1, 10-2, 10-3 ···, 10-n to the RFID reader / writer 20 in response to the signal from the RFID reader / writer 20.

[0035] Specifically, the location where the water pipe 3 has a water leakage is detected based on the response signals including the EPC transmitted from each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n in response to the signal transmitted from the RFID reader / writer 20 and / or the RSSI values of each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n measured by the RFID reader / writer 20.

[0036] The control device 30 determines whether it has received signals including EPC from all of the plurality of RFID tags 10-1, 10-2, 10-3, ···, 10-n embedded along the water pipe 3 buried in the ground 5. When it is determined that signals including EPC have been received from all of the RFID tags 10-1, 10-2, 10-3, ···, 10-n, the control device 30 detects that there is no water leakage point X in the water pipe 3. When it is determined that signals including EPC from any one of the RFID tags 10-1, 10-2, 10-3, ···, 10-n among all of the RFID tags 10-1, 10-2, 10-3, ···, 10-n cannot be received, the control device 30 detects that water leakage has occurred at a location near the RFID tag 10 from which the signal could not be received. In the embodiment shown in FIG. 2, since the signal of the end “00005” of the EPC corresponding to the RFID tag 10-5 could not be received, the control device 30 can detect that water leakage has occurred at a location near the RFID tag 10-5 from which the signal could not be received.

[0037] Furthermore, the control device 30 may determine whether the RSSI values of all of the plurality of RFID tags 10-1, 10-2, 10-3, ···, 10-n embedded along the water pipe 3 buried in the ground 5 are equal to or greater than a threshold value. When it is determined that the RSSI values of all of the RFID tags 10-1, 10-2, 10-3, ···, 10-n are equal to or greater than the threshold value, the control device 30 detects that there is no water leakage point X in the water pipe 3. When it is determined that the RSSI value of any one of the RFID tags 10-1, 10-2, 10-3, ···, 10-n among the RSSI values of all of the RFID tags 10-1, 10-2, 10-3, ···, 10-n is less than the threshold value, the control device 30 detects that water leakage has occurred at a location near the RFID tag 10 for which it is determined that the value is less than the threshold value. In the embodiment shown in FIG. 2, since the RSSI value corresponding to the RFID tag 10-5 is less than the threshold value, the control device 30 can detect that water leakage has occurred at a location near the RFID tag 10-6 for which it is determined that the value is less than the threshold value.

[0038] FIG. 3 is a diagram showing an example of the hardware configuration of the RFID reader / writer 20 according to the present embodiment. The RFID reader / writer 20 includes a reader / writer control unit 21, a storage unit 22, and a communication interface 23. The RFID reader / writer 20 may have a circuit configuration other than the configuration described in FIG. 3.

[0039] The reader / writer control unit 21 comprehensively controls the entire RFID reader / writer 20 and has a CPU (not shown) that reads a program and executes control processing.

[0040] The reader / writer control unit 21 is, for example, a CPU (Central Processing Unit) (not shown), and controls the operation of the entire reader / writer control unit 21 by expanding the programs stored in the RAM (Random Access Memory), ROM (Read Only Memory), SSD (Solid State Drive), etc. of the storage unit 22 into the RAM of the storage unit 22 and sequentially executing them. The reader / writer control unit 21 controls the overall operation of the RFID reader / writer 20 by executing various programs such as an OS (Operating System) program and an application program.

[0041] The communication interface 23 transmits and receives data and commands to and from the RFID tag 10 through the antenna 6. Further, the communication interface 23 transmits data including RFID identification information to the control device 30. In the present embodiment, the antenna 6 is built in the RFID reader / writer 20, but this is not the case in all instances. The antenna 6 may be configured as an external component of the RFID reader / writer 20.

[0042] FIG. 4 is a diagram showing an example of the hardware configuration of the control device 30 according to the present embodiment. The control device 30 includes a control unit 31, a storage unit 32, a display unit 33, and a communication interface 34. The control device 30 is communicably connected to each RFID reader / writer 20 wirelessly or wiredly through the communication interface 34. The control device 30 and the RFID reader / writer 20 may be communicably connected through the Internet or a dedicated line.

[0043] The control device 30 is configured by a mobile terminal such as a smartphone, for example. The control device 30 may be configured by a computer such as a server or a cloud server constructed on the Internet.

[0044] The control device 30 detects a water leakage location of the water pipe 3 based on response signals transmitted from a plurality of RFID tags 10-1, 10-2, 10-3 ···, 10-n to the RFID reader / writer 20.

[0045] The control unit 31 comprehensively controls the entire control device 30 and has a CPU that reads a program and executes control processing.

[0046] The control unit 31 is a CPU or the like, and controls the operation of the entire control unit 31 by expanding programs stored in the RAM, ROM, SSD, etc. of the storage unit 32 into the RAM of the storage unit 32 and sequentially executing them. The control unit 31 controls the overall operation of the control device 30 by executing various programs such as the OS program and application programs.

[0047] The display unit 33 displays the EPCs and RSSI values of the respective RFID tags 10-1, 10-2, 10-3 ···, 10-n received through the RFID reader / writer 20. The operator of the water leakage detection system 1 can grasp the water leakage situation of the water pipe 3 in which the respective RFID tags 10-1, 10-2, 10-3 ···, 10-n are embedded and specify the water leakage location X by checking the EPCs and RSSI values displayed on the display unit 33.

[0048] The communication interface 34 is composed of a network adapter or the like. The control device 30 receives signals of EPCs and RSSI values transmitted from each RFID reader / writer 20 through the communication interface 34.

[0049] In the water leakage detection system 1 according to the above-described embodiment, when the control device 30 determines that it cannot receive a signal including the EPC of any one of all the RFID tags 10-1, 10-2, 10-3,..., 10-n embedded in the ground 5, it can detect that water leakage has occurred at a location near the RFID tag 10 for which the signal could not be received. Further, when the control device 30 determines that the RSSI value of a response signal transmitted from any one of all the RFID tags 10-1, 10-2, 10-3,..., 10-n among the RSSI values of all the RFID tags 10-1, 10-2, 10-3,..., 10-n embedded in the ground 5 is less than the threshold value, it can detect that water leakage has occurred at a location near the RFID tag 10 determined to be less than the threshold value. Thereby, the water leakage location X of the water pipe 3 embedded in the ground 5 can be easily detected.

[0050] (Another Embodiment) In the above-described embodiment, the antenna 6 of the RFID reader / writer 20 is built in the RFID reader / writer 20. However, in another embodiment, as shown in FIG. 5, the antenna 6 is formed in a cable shape as an external component of the RFID reader / writer 20.

[0051] The RFID reader / writer 20 according to another embodiment is composed of a stationary device. The RFID reader / writer 20 according to another embodiment may be composed of a portable device. Among the hardware configurations of the RFID reader / writer 20 according to another embodiment, the hardware configurations other than the antenna 6 are the same as those in the above-described embodiment, and thus the description thereof is omitted.

[0052] FIG. 5 is a diagram showing a state in which water leakage has occurred in an example of the water leakage detection system 1 according to another embodiment. Since the configuration of the water leakage detection system 1 according to another embodiment is the same as that of the above-described embodiment except for the antenna 6, the same reference numerals are given and the description thereof is omitted.

[0053] An RFID reader / writer 20 is connected to one end of the cable-shaped antenna 6, and a terminating resistor 40 is connected to the other end of the antenna 6. The terminating resistor 40 is used to prevent reflection of signals from the antenna 6. The main purpose of the terminating resistor 40 is to optimize the signal transmission efficiency by matching the characteristic impedance of the antenna 6, and to minimize signal loss and interference due to reflection.

[0054] The cable-shaped antenna 6 is buried along the water pipe 3. That is, the antenna 6 is buried along each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n buried along the water pipe 3, and at a distance D1 above the vertical direction of each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n. The antenna 6 may be buried below the vertical direction of each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n or on the horizontal side of each of the RFID tags 10-1, 10-2, 10-3 ···, 10-n.

[0055] The RFID reader / writer 20 transmits signals (also referred to as "reading instructions") to the RFID tags 10-1, 10-2, 10-3 ···, 10-n to the cable-shaped antenna 6 at a predetermined timing. The predetermined timing may be a regular timing or an arbitrary timing. As the regular timing, an arbitrary period such as a predetermined time, number of days, number of months, number of years, etc. can be set. Thereby, constant monitoring of water leakage in the water pipe 3 can be realized. Also, as the arbitrary timing, an arbitrary date and time when an operator using the water leakage detection system 1 performs maintenance may be set. Thereby, water leakage monitoring by the operator using the water leakage detection system 1 can be realized without waiting for the result of the water meter reading of the water flowing through the water pipe 3.

[0056] Also, as a predetermined timing, when the RFID reader / writer 20 detects an earthquake early warning of a predetermined seismic intensity (for example, seismic intensity 3 or higher) or actually detects an earthquake of a predetermined seismic intensity (for example, seismic intensity 3 or higher), the RFID reader / writer 20 may immediately transmit signals to the RFID tags 10-1, 10-2, 10-3 ···, 10-n via the cable-shaped antenna 6. Also, when the RFID reader / writer 20 detects an earthquake early warning of a predetermined seismic intensity (for example, seismic intensity 3 or higher) or actually detects an earthquake of a predetermined seismic intensity (for example, seismic intensity 3 or higher), the interval for transmitting signals to the RFID tags 10-1, 10-2, 10-3 ···, 10-n may be temporarily shortened. Thereby, water leakage of the water pipe 3 due to the influence of the earthquake can be immediately detected, and by enabling timely leakage detection, the damage caused by water leakage of the water pipe 3 can be minimized.

[0057] In the above-described embodiment, the RFID reader / writer 20 detects an earthquake early warning or an actual earthquake, but this is not the only case. For example, based on the earthquake early warning or the information of the actual earthquake detected by the control device 30, the RFID reader / writer 20 may immediately transmit signals to the RFID tags 10-1, 10-2, 10-3 ···, 10-n via the cable-shaped antenna 6.

[0058] In the above-described embodiment, the RFID reader / writer 20 and the control device 30 have separate configurations, but this is not the only case, and the RFID reader / writer 20 and the control device 30 may be integrally configured.

[0059] Note that the present invention is not limited to the above-described embodiments as they are, and the components can be modified and embodied without departing from the gist thereof at the implementation stage. Also, various inventions can be formed by appropriately combining a plurality of components disclosed in the above-described embodiments. For example, all the components shown in the embodiments may be appropriately combined. Furthermore, components from different embodiments may be appropriately combined. Needless to say, various modifications and applications can be made without departing from the spirit of the invention.

Explanation of Signs

[0060] 1: Detection system 3: Water pipe 4: Encapsulating tape 5: Underground 5-1: Soil 5-2: Soil 6: Antenna 7: Ground surface 8: Water 10: RFID tag 20: RFID reader / writer 21: Reader / writer control unit 22: Memory unit 23: Communication interface 30: Control device 31: Control unit 32: Memory unit 33: Display unit 34: Communication interface 40: Terminal resistor X: Water leakage point

Claims

1. A water leakage detection system comprising: a plurality of RFID tags embedded along a water pipe buried in the ground; an RFID reader / writer connected to an antenna that communicates with the plurality of RFID tags; and a control device connected to the RFID reader / writer, wherein the plurality of RFID tags are continuously embedded in the ground at predetermined intervals along the water pipe, and the control device detects a location where the water pipe has leaked based on signals transmitted from the plurality of RFID tags to the RFID reader / writer. A water leakage detection system characterized by the above.

2. The plurality of RFID tags are continuously embedded in parallel with the water pipe. The water leakage detection system according to Claim 1, characterized by the above.

3. The plurality of RFID tags are enclosed in a long tape and continuously embedded at the predetermined intervals. The water leakage detection system according to Claim 2, characterized by the above.

4. The antenna is formed in a cable shape and is embedded along the water pipe. The water leakage detection system according to Claim 3, characterized by the above.

5. Each of the plurality of RFID tags is continuously assigned an EPC that can identify the RFID tag, and the control device detects a location where the water pipe has leaked based on the EPC included in signals received from the plurality of RFID tags continuously embedded along the water pipe. The water leakage detection system according to any one of Claims 1 to 4, characterized by the above.

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