Liquid leakage detection device

Abstract

To provide a liquid leakage detection technique capable of eliminating the necessity of always energizing the electrode of a detector and independently performing liquid leakage detection and disconnection confirmation.SOLUTION: A liquid leakage detection device 10A (10) includes a detector 15 having a pair of first and second electrodes 11 and 12 which are electrically conducted through a liquid when the liquid comes into contact therewith and through which a detection signal 16 for detecting liquid leakage passes, a first detection cord 21 which is connected to the first electrodes 11 and through which the detection signal 16 passes, and a second detection cord 22 which is connected to the second electrodes 12 and through which the detection signal 16 passes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a liquid leakage detection device having a function of checking for disconnection. [Background technology]

[0002] The principle of liquid leakage detection is based on the phenomenon that current flows when a conductive liquid, such as water, comes into contact with a pair of electrodes that make up the detector. The current that flows through the electrode that comes into contact with the leaking liquid travels through the cable and is detected by the detection circuit.

[0003] If the cable breaks, the detection circuit may not be able to detect the leak even if the liquid comes into contact with the detector. For this reason, liquid leakage detection devices are equipped with a function to check for cable breaks. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2-216427 [Patent Document 2] Japanese Patent Application Publication No. 10-160547 Summary of the Invention [Problem to be solved by the invention]

[0005] Prior art discloses a technique for detecting leaks by sandwiching an electrical resistor between electrodes to ensure that current flows constantly through the circuit, and detecting a change in circuit resistance when the leaking liquid comes into contact with the electrodes. With this technique, a break in the circuit is confirmed when the current flowing through the circuit becomes zero. However, this prior art has the problem that the detector electrodes must be constantly energized during the leak detection period.

[0006] In another prior art, an abnormal rise in water level or leakage in the water tray of a dishwasher was reported. A detector for detecting the occurrence of a leak has been disclosed. According to this prior art, a break is confirmed based on the potential of a resistor provided at the opposite end of a cable that passes a current to each of the opposing electrodes. However, in this case (as in the prior art described above), the break is also confirmed using the current (signal) that detects the leak. Therefore, even in this case, there is a problem in that the detector electrodes must be constantly energized during the leak detection period.

[0007] The embodiments of the present invention have been made in consideration of these circumstances, and aim to provide a leak detection technology that eliminates the need to constantly energize the detector electrodes and allows leak detection and disconnection confirmation to be performed independently. [Means for solving the problem]

[0008] In the liquid leakage detection device of the embodiment, the device comprises a detector having a pair of first and second electrodes that become electrically conductive via the liquid when the liquid comes into contact with the detector and through which a detection signal that detects a liquid leakage passes; a first detection cord connected to the first electrode and passing the detection signal; a second detection cord connected to the second electrode and passing the detection signal; a first confirmation cord connected in series with the first detection cord and passing a first confirmation signal that confirms that the first detection cord is not broken; a second confirmation cord connected in series with the second detection cord and passing a second confirmation signal that confirms that the second detection cord is not broken; and a cable formed by bundling the first detection cord, the second detection cord, the first confirmation cord, and the second confirmation cord. [Effects of the Invention]

[0009] The embodiments of the present invention provide a leak detection technology that eliminates the need to constantly energize the electrodes of the detector and allows leak detection and disconnection confirmation to be performed independently. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a liquid leakage detection device according to a first embodiment of the present invention. [Figure 2](A) A diagram showing the configuration of a leakage detection device according to a second embodiment, illustrating the circuit state in which the first detection code is checked for disconnection, and (B) the same diagram showing the circuit state in which the second detection code is checked for disconnection. [Figure 3] FIG. 10 is a configuration diagram showing a modified example of the liquid leakage detection device according to the second embodiment. [Figure 4] (A) A diagram showing the configuration of a liquid leakage detection device according to a third embodiment, illustrating the circuit state in which a detector's cable is checked for disconnection, and (B) the same diagram showing the circuit state in which another detector's cable is checked for disconnection. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a configuration diagram of a liquid leakage detection device 10A (10) according to a first embodiment of the present invention. As described above, the liquid leakage detection device 10A (10) includes a detector 15 having a pair of first and second electrodes 11 and 12 that, when contacted with liquid, become electrically conductive via the liquid and pass a detection signal 16 that detects a liquid leakage, a first detection cord 21 connected to the first electrode 11 and passing the detection signal 16, and a second detection cord 22 connected to the second electrode 12 and passing the detection signal 16.

[0012] Furthermore, the leakage detection device 10A includes a first confirmation cord 31 connected in series with the first detection cord 21 and passing a first confirmation signal 41 to confirm that the first detection cord 21 is not broken, a second confirmation cord 32 connected in series with the second detection cord 22 and passing a second confirmation signal 42 to confirm that the second detection cord 22 is not broken, and a cable 17 formed by bundling the first detection cord 21, the second detection cord 22, the first confirmation cord 31 and the second confirmation cord 32.

[0013] The electrode spacing between the first electrode 11 and the second electrode 12 is set so that the impedance of the liquid in contact with them matches the specifications of the detection circuit 55 (Fig. 2). Depending on the electrical conductivity of the liquid in contact with them, either a detector 15 with an appropriate electrode spacing set is used, or the current detection range of the detection circuit 55 is switched to accommodate the difference.

[0014] Each of the first detection cord 21, the second detection cord 22, the first confirmation cord 31, and the second confirmation cord 32 is a flexible and bendable metallic electrical conductor covered with an insulator. The cable 17 has these four cords 21, 22, 31, and 32 bundled together and housed in an insulating covering tube, and has a flexible and bendable four-core structure.

[0015] The tips of the four cords 21, 22, 31, and 32 are exposed from the openings of the covering tubes at both ends of the cable 17. The exposed tips of the four cords 21, 22, 31, and 32 are connected to a terminal 25 on the detector 15 side and a terminal 28 on the terminal block 18.

[0016] Of the four terminals 25 of the detector 15, the terminals 25 connected to the first detection code 21 and the first confirmation code 31 are electrically connected to each other in advance. Similarly, the terminals 25 connected to the second detection code 22 and the second confirmation code 32 are also electrically connected to each other in advance. Of the four terminals 25 of the detector 15, the terminals 25 connected to the first detection code 21 and the second detection code 22 are connected to the first electrode 11 and the second electrode 12.

[0017] Furthermore, the liquid leakage detection device 10A is equipped with a detection circuit 55 that detects the liquid leakage based on whether or not it receives a detection signal 16 transmitted from the first detection code 21 and the second detection code 22, a first confirmation circuit 51 that confirms whether or not it receives a first confirmation signal 41 transmitted from the first detection code 21 and the first confirmation code 31, and a second confirmation circuit 52 that confirms whether or not it receives a second confirmation signal 42 transmitted from the second detection code 22 and the second confirmation code 32.

[0018] Of the four sets of terminals 28 on the terminal block 18 side, the terminals 28 connected to the first detection cord 21 and the second detection cord 22 are connected to the wiring of the detection circuit 55. As a result, when the first electrode 11 and the second electrode 12 are electrically short-circuited due to a liquid leak, the electrical circuit transitions from an open state to a closed state. This completes the transmission and reception of the detection signal 16 in the detection circuit 55, and the occurrence of a liquid leak is detected.

[0019] Of the four sets of terminals 28, the terminals 28 connected to the first detection cord 21 and the first confirmation cord 31 are connected to the first confirmation circuit 51, closing the electric circuit. As a result, if the first detection cord 21 is broken, the electric circuit transitions from the closed state to the open state. Then, the first confirmation circuit 51 stops sending and receiving the first confirmation signal 41, and the break in the first detection cord 21 is confirmed.

[0020] Of the four sets of terminals 28, the terminals 28 connected to the second detection cord 22 and the second confirmation cord 32 are connected to the second confirmation circuit 52, closing the electric circuit. As a result, if the second detection cord 22 is broken, the electric circuit transitions from the closed state to the open state. Then, the second confirmation circuit 52 stops sending and receiving the second confirmation signal 42, and the break in the second detection cord 22 is confirmed.

[0021] In the liquid leakage detection device 10, the configuration consisting of the first confirmation circuit 51, the second confirmation circuit 52, and the detection circuit 55 connected to the terminal block 18 is an example, and the device is not limited to this configuration. In the liquid leakage detection device 10, any configuration that can perform the functions of detecting liquid leakage and checking for disconnections can be appropriately adopted and connected to the terminal block 18.

[0022] Furthermore, the first confirmation circuit 51, the second confirmation circuit 52, and the detection circuit 55 can use a common circuit unit. In this case, it is advisable to differentiate the circuit resistance of the first confirmation circuit 51 and the second confirmation circuit 52 from the circuit resistance of the detection circuit 55. In practice, the confirmation circuits 51 and 52 are adjusted to a circuit resistance that allows a minute current to flow in order to detect a break, and the detection circuit 55 is adjusted to an optimum circuit resistance depending on the resistivity of the conductive liquid with which it comes into contact. In any case, the first confirmation circuit 51 and the second confirmation circuit 52 have mutually adjustable configurations that differentiate their circuit resistances.

[0023] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Figures 2 and 3. Figure 2(A) is a configuration diagram of a liquid leakage detection device 10B (10) according to the second embodiment, showing the circuit state in which the presence or absence of a break in the first detection code 21 is confirmed, and Figure 2(B) is a diagram showing the circuit state in which the presence or absence of a break in the second detection code 22 is confirmed. Figure 3 is a configuration diagram showing a modified example of the liquid leakage detection device 10B (10) according to the second embodiment. In Figures 2 and 3, parts having the same configuration or function as those in Figure 1 are designated by the same reference numerals, and duplicate explanations will be omitted.

[0024] In the first embodiment described above, a pair of confirmation circuits 51, 52 was used to check for disconnection of the cable 17 of one detector 15. In contrast, the liquid leakage detection device 10B (10) of the second embodiment differs in that a pair of confirmation circuits 51, 52 is used to check for disconnection of the cables 17 of multiple detectors 15. Note that the pair of confirmation circuits 51, 52 checks for disconnection of two detectors 15 in FIG. 2 and four detectors 15 in FIG. 3. Note that in the second embodiment, there is no particular limit to the number of detectors 15 connected for liquid leakage detection and disconnection check.

[0025] 2 and 3, in the liquid leakage detection device 10B (10) of the second embodiment, the first detection code 21 and the second detection code 22 in each of the multiple detectors 15 are connected to a unique detection circuit 55. The first detection code 21 and the first confirmation code 31 in each of the multiple detectors 15 are connected in series to a common first confirmation circuit 51. The second detection code 22 and the second confirmation code 32 in each of the multiple detectors 15 are connected in series to a common second confirmation circuit 52.

[0026] Furthermore, the leakage detection device 10B (10) is equipped with a first opening / closing switch 61 that opens / closes the circuit formed by the first detection cord 21 and the first confirmation cord 31 that are connected to the first confirmation circuit 51, and a second opening / closing switch 62 that opens / closes the circuit formed by the second detection cord 22 and the second confirmation cord 32 that are connected to the second confirmation circuit 52.

[0027] In the second embodiment, all combinations of the first detection codes 21 and the first confirmation codes 31 that make up the liquid leakage detection device 10B (10) are connected in series to the first confirmation circuit 51. As a result, by closing the first open / close switch 61, it is possible to check at once whether or not there is a break in all of the first detection codes 21 connected to the multiple detectors 15.

[0028] Similarly, all combinations of the second detection codes 22 and the second confirmation codes 32 that make up the liquid leakage detection device 10B (10) are connected in series to the first confirmation circuit 51 of the second embodiment. As a result, by closing the second open / close switch 62, it is possible to check at once whether all the second detection codes 22 connected to the multiple detectors 15 are broken.

[0029] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Fig. 4. Fig. 4(A) is a configuration diagram of a liquid leakage detection device 10C(10) according to the third embodiment, showing the circuit state in which the presence or absence of a break in the cable 17 of the detector 15a is being checked. Fig. 4(B) is a similar diagram showing the circuit state in which the presence or absence of a break in the cable 17 of another detector 15b is being checked. In Fig. 4, parts having the same configuration or function as those in Fig. 1 are designated by the same reference numerals, and duplicate explanations will be omitted.

[0030] The liquid leakage detection device 10C(10) of the third embodiment differs in that, whereas in the second embodiment described above, a single check is performed to check for disconnections in the cables 17 of all target detectors 15, the third embodiment checks for disconnections in the cables 17 of multiple detectors 15 individually. Note that although Fig. 4 shows a configuration for checking two detectors 15, a configuration for checking for disconnections in three or more detectors 15 may also be used. In the third embodiment, there is no particular limit to the number of detectors 15 connected for liquid leakage detection and disconnection check.

[0031] 4, in the liquid leakage detection device 10C(10) of the third embodiment, the first detection code 21 and the second detection code 22 in each of the multiple detectors 15 are connected to a unique detection circuit 55. The first detection code 21 and the first confirmation code 31 in each of the multiple detectors 15 are connected in parallel to a common first confirmation circuit 51. The second detection code 22 and the second confirmation code 32 in each of the multiple detectors 15 are connected in parallel to a common second confirmation circuit 52.

[0032] All of the combinations of the first detection codes 21 and first confirmation codes 31 that make up the leakage detection device 10B (10) are connected in parallel to the first confirmation circuit 51 of the second embodiment. As a result, by closing the first open / close switch 61 provided corresponding to each detector 15, it is possible to individually check whether the corresponding first detection code 21 is broken.

[0033] Similarly, all combinations of the second detection codes 22 and second confirmation codes 32 that make up the leakage detection device 10B (10) are connected in parallel to the first confirmation circuit 51 of the second embodiment. As a result, by closing the second open / close switches 62 provided corresponding to each detector 15, it is possible to individually check whether the corresponding second detection code 22 is broken.

[0034] According to at least one of the embodiments of the liquid leakage detection device described above, by using a cable that bundles together a detection cord that connects to the detector electrode and a confirmation cord that checks for a break in the detection cord, it is possible to perform liquid leakage detection and check for a break independently.

[0035] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents. [Explanation of symbols]

[0036] 10 (10A, 10B, 10C)...leak detection device, 11...first electrode, 12...second electrode, 5 (15a, 15b)...detector, 16...detection signal, 17...cable, 18...terminal block, 21...first detection code, 22...second detection code, 25...terminal, 28...terminal, 31...first confirmation code, 32...second confirmation code, 41...first confirmation signal, 42...second confirmation signal, 51...first confirmation circuit, 52...confirmation circuit, 55...detection circuit, 61...first opening / closing switch, 62...second opening / closing switch.

Claims

1. a detector having a pair of first and second electrodes that are electrically connected via the liquid when the detector comes into contact with the liquid, and through which a detection signal for detecting a liquid leak passes; a first detection cord connected to the first electrode and allowing the detection signal to pass; a second detection cord connected to the second electrode and allowing the detection signal to pass; a first confirmation code connected in series with the first detection code and passing a first confirmation signal for confirming that the first detection code is not broken; a second confirmation code connected in series with the second detection code and passing a second confirmation signal for confirming that the second detection code is not broken; a cable formed by bundling the first detection cord, the second detection cord, the first confirmation cord, and the second confirmation cord.

2. 2. The liquid leakage detection device according to claim 1, a detection circuit connected to the first detection cord and the second detection cord, which detects the liquid leakage based on whether or not the transmitted detection signal is received; a first confirmation circuit connected to the first detection code and the first confirmation code, and confirming whether or not the disconnection exists based on whether or not the transmitted first confirmation signal is received; a second confirmation circuit connected to the second detection cord and the second confirmation cord, and configured to confirm whether or not the disconnection has occurred based on whether or not the transmitted second confirmation signal has been received;

3. 3. The liquid leakage detection device according to claim 2, In each of the plurality of detectors, the first detection code and the second detection code are connected to a specific detection circuit; the first detection code and the first confirmation code in each of the plurality of detectors are connected in series to a common first confirmation circuit; A liquid leakage detection device, wherein the second detection code and the second confirmation code in each of the plurality of detectors are connected in series to the common second confirmation circuit.

4. 3. The liquid leakage detection device according to claim 2, In each of the plurality of detectors, the first detection code and the second detection code are connected to a specific detection circuit; the first detection code and the first confirmation code in each of the plurality of detectors are connected in parallel to a common first confirmation circuit; A liquid leakage detection device, wherein the second detection code and the second confirmation code in each of the plurality of detectors are connected in parallel to the common second confirmation circuit.

5. 5. The liquid leakage detection device according to claim 3 or 4, a first open / close switch for opening / closing a circuit formed by the first detection code and the first confirmation code connected to the first confirmation circuit; a second open / close switch that opens / closes the circuit formed by the second detection cord and the second confirmation cord, the second detection cord being connected to the second confirmation circuit;

6. The liquid leakage detection device according to any one of claims 2 to 4, The first confirmation circuit and the second confirmation circuit have mutually adjustable configurations so that there is a difference in circuit resistance between the two circuits.

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