JP2010216923A - Liquid leak detection method and liquid leak detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid leak detection method and a liquid leak detection system in which construction and maintenance are relatively simple, liquid leak is detected at an early stage, and reliability is high. <P>SOLUTION: A passive IC tag 13 is arranged at a pipe connection part, and a porous sheet 16 is arranged at the periphery thereof. An electromagnetic shield film 15 made of water-soluble conductive polymer and a resin film 17 are arranged at the periphery of the porous sheet 16 to interrupt communications between the IC tag 13 and an IC tag reader. When liquid leak occurs, the leaking liquid diffuses through the porous sheet 16 and is in contact with the electromagnetic shield sheet 15. Thus, the electromagnetic shield sheet 15 is dissolved into the liquid and disappears. Accordingly, the communications between the IC tag 13 and the IC tag reader are allowed to detect the occurrence of liquid leak. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid leakage detection method and a liquid leakage detection system for detecting liquid leakage.

  The electronic computer is provided with a cooling mechanism for removing heat generated by operation. Some machine tools that perform processing such as cutting and cutting require a cooling mechanism. General cooling mechanisms are roughly classified into an air cooling type and a liquid cooling type. The liquid cooling type cooling mechanism has an advantage of high cooling efficiency, and is used for cooling a device that generates a large amount of heat.

  In the liquid cooling type cooling mechanism, for example, a coolant is circulated between the vicinity of the heat source and the radiator to transfer heat generated in the heat source to the radiator, and heat is dissipated from the radiator to the outside. In this case, if the liquid leaks from the piping through which the coolant flows (including hose and joints; the same applies hereinafter), the temperature of the device rises and normal operation cannot be performed. Sometimes. There is also a possibility that the electric system may be short-circuited by the leaked liquid. For this reason, it is necessary to detect liquid leakage at an early stage and take some countermeasures.

  As a method for detecting liquid leakage, it has been proposed to dispose a hygroscopic agent and a humidity sensor around a pipe. In addition, it has been proposed that an IC chip that transmits radio waves is attached to a pipe and that a liquid leak is detected by utilizing the fact that the transmission function of the IC chip is stopped or inhibited by contact with leaked water.

JP-A-8-185717 JP 2000-164390 A JP 2006-258684 A JP 2007-163255 A JP 2007-218839 A

  However, in the method of detecting liquid leakage using a humidity sensor, when there are many liquid leakage monitoring locations, it is necessary to attach a humidity sensor to each monitoring location, and there is a problem that wiring work and maintenance become complicated. On the other hand, in the method of detecting liquid leakage using the fact that the transmission function of the IC chip is stopped or hindered by contact with leaked water, depending on the IC chip mounting method, etc., the liquid leakage occurs. Therefore, there is an uncertain problem that it takes time until the transmission function of the IC chip is reliably stopped or hindered.

  In view of the above, it is an object of the present invention to provide a liquid leakage detection method and a liquid leakage detection system that are relatively simple in construction and maintenance, can detect liquid leakage at an early stage, and have high reliability.

  According to one aspect, an IC tag and a porous sheet that absorbs and diffuses the liquid leaked from the pipe are arranged around a pipe through which the liquid passes, and the liquid is in contact with a portion in contact with the porous sheet. The conductor film disappearing in the step is arranged so as to surround the IC tag, the antenna of the IC tag reader is arranged on the opposite side of the IC tag across the conductor film, and the IC tag reader removes the IC tag from the IC tag. There is provided a liquid leak detection method for detecting the presence or absence of a liquid leak by detecting the presence or absence of an output electromagnetic wave.

  According to the above aspect, the IC tag and the porous sheet are arranged around the pipe, and the IC tag is surrounded by a portion in contact with the porous sheet (for example, the periphery of the porous sheet or the surface of the IC tag). A conductive film that is easily dissolved in the liquid is disposed. In a state where there is no liquid leakage, the electromagnetic wave is shielded by the conductor film, and communication between the IC tag and the IC tag reader cannot be performed. However, when liquid leakage occurs, the porous sheet absorbs and diffuses the liquid, and the liquid comes into contact with the conductor film. As a result, the conductor film dissolves and disappears in the liquid, and communication between the IC tag and the IC tag reader becomes possible. Therefore, if communication between the IC tag and the IC tag reader is impossible, it is determined that there is no liquid leakage, and if communication between the IC tag and the IC tag reader is possible, it is determined that liquid leakage has occurred. it can.

FIG. 1 is a side view showing a state in which a hose assembly through which cooling water passes is attached to a side surface of a housing of an apparatus having a heat source (for example, an electronic computer). FIG. 2 is a cross-sectional view showing the liquid leakage detection method according to the first embodiment, and shows a cross section obtained by cutting the tip of the hose assembly shown in FIG. 1 along a plane parallel to the paper surface. FIG. 3 is a cross-sectional view taken along the line II of FIG. FIG. 4 is a diagram illustrating the liquid leakage detection method according to the first embodiment, and illustrates a cooling water hose assembly attachment portion on a side surface of a housing of an apparatus having a heat source. FIG. 5 is a schematic view showing an IC tag laminated on a pair of moisture-proof films. FIG. 6 is a block diagram showing the configuration of the IC tag. FIG. 7 is a block diagram showing the configuration of the IC tag reader. FIG. 8 is a flowchart showing the operation at the time of detecting a liquid leak. FIG. 9 is a schematic diagram showing a state in which the electromagnetic shielding film is dissolved and disappeared by the liquid leaked from the pipe. FIG. 10 is a diagram illustrating a liquid leak detection method according to the second embodiment.

  Hereinafter, embodiments will be described with reference to the accompanying drawings.

(First embodiment)
1st Embodiment demonstrates the case where the liquid leak of the coupling metal fitting part of the front-end | tip of a hose assembly is detected. 1 to 4 are diagrams showing a liquid leakage detection method according to the first embodiment. FIG. 1 is a side view showing a state in which a hose assembly through which cooling water passes is attached to the side of a housing of an apparatus having a heat source (for example, an electronic computer). 2 is a cross-sectional view of the hose assembly shown in FIG. 1 cut along a plane parallel to the paper surface, and FIG. 3 is a cross-sectional view taken along the line II of FIG. Furthermore, FIG. 4 is a figure which shows the cooling water hose assembly attachment part of the housing | casing side surface of the apparatus which has a heat source.

  As shown in FIG. 2, the hose assembly 10 is formed by connecting a joint fitting 12 to an end of a resin or rubber hose 11 having flexibility. The hose 11 is inserted into the groove 12a of the joint fitting 12, and is fixed to the joint fitting 12 by caulking the groove 12a. Further, a male thread 12 b is formed on the peripheral surface of the distal end portion of the joint fitting 12.

  As shown in FIGS. 2 and 3, a passive (non-powered) IC tag (RFID) 13 is attached on a connecting portion (hereinafter also simply referred to as “connecting portion”) between the hose 11 and the fitting 12. It has been. As shown in FIG. 5, the IC tag 13 is sandwiched and laminated between a pair of moisture-proof films 18 and is protected from moisture by these moisture-proof films 18, so that the function is impaired even if water leakage occurs. There is no. As the moisture-proof film 18, for example, a PVC (polyvinyl chloride) or PET (polyethylene terephthalate) film can be used. Details of the IC tag 13 will be described later.

  A porous sheet 16 made of, for example, a woven fabric or a non-woven fabric is wound around the IC tag 13 and the connection portion. Note that a resin low-density sintered body or a resin foam may be used for the porous sheet 16. The porous sheet 16 can absorb moisture and quickly spread the moisture absorbed by the capillary phenomenon throughout the porous sheet 16.

  Around the porous sheet 16, for example, a case 17 made of a PET (polyethylene terephthalate) resin film having a thickness of about 100 μm is disposed. The case 17 prevents liquid leakage to the outside when liquid leakage occurs from the connecting portion, and prevents water from entering from the outside to prevent erroneous detection of liquid leakage due to condensation.

  On the inner peripheral surface of the case 17 (surface in contact with the porous sheet 16), an electromagnetic shielding film (conductor film) 15 made of a water-soluble conductive polymer film having a thickness of about 10 μm, for example, is formed. The electromagnetic shielding film 15 blocks electromagnetic waves from an IC tag reader 40 described later. When the liquid leakage occurs, the electromagnetic shielding film 15 dissolves in the water in the porous sheet 16 and disappears, and loses the electromagnetic shielding ability. Examples of the water-soluble conductive polymer used for the electromagnetic shielding film 15 include Aquapath (registered trademark) manufactured by Mitsubishi Rayon Co., Ltd., Baytron (registered trademark) manufactured by Bayer, and Espacer (registered trademark) manufactured by Showa Denko K.K. Can be used. In addition to these, any material that has water-solubility and sufficient conductivity and has an electromagnetic wave shielding ability can be used for the electromagnetic shielding film 15 and can be formed by drying it.

  A hygroscopic expansion material sheet (liquid absorbent material) 14 is disposed at the end of the porous sheet 16. The hygroscopic expansion material sheet 14 includes a resin that expands when it absorbs moisture, and absorbs water when the liquid leaks from the pipe and expands to close the gap between the case 17 and the pipe. Prevent liquid leaks. Resins that expand when they absorb moisture include polyacrylic acid resins, poval resins, polyoxyethylene resins, and cellulose resins. For example, Aqua Pearl, Sun Fresh, Sun Wet (registered trademark) manufactured by Sanyo Chemical Industries, Ltd., Aquaric CA (registered trademark) manufactured by Nippon Shokubai Co., Ltd., Aqua Keep, Aqua Coke manufactured by Sumitomo Seika Co., Ltd. (Both are registered trademarks), Bel Oasis (registered trademark) manufactured by Teijin Fibers Limited, and the like can be used. Moreover, as a resin material having a similar function, a foamed foam of a polyurethane resin having a carboxylic acid group or a sulfonic acid group that gives a moisture absorption function to the internal molecular structure may be used. In this case, the water stop function can be enhanced by providing a skin layer having a high resin density on the outermost layer of the polyurethane foam.

  On the other hand, as shown in FIG. 1, a cooling water hose assembly attachment port 21 is provided on the side of the housing of the device 20 having a heat source. An internal thread is formed on the inner surface of the cooling water hose assembly attachment port 21, and the tip of the fitting 12 is screwed into the cooling water hose attachment port 21 to connect the hose assembly 10 to the cooling water hose assembly attachment port 21. . Here, as shown in FIG. 4, the apparatus 20 has two cooling water pipes, that is, two cooling water supply pipes (IN) and two cooling water return pipes (OUT).

  As shown in FIGS. 1 and 4, an antenna 41 of the IC tag reader 40 is disposed in the vicinity of the cooling water hose assembly attachment port 21 on the side surface of the housing of the apparatus 20. A member denoted by reference numeral 22 in FIG. 1 is a fixing tool for fixing the antenna 41 to the device 20, and the fixing tool 22 is formed of an insulating material such as plastic.

  In the present embodiment, as shown in FIG. 4, the antenna 41 of the IC tag reader 40 is disposed so as to pass in the vicinity of the four cooling water hose assembly connection portions. Thereby, the liquid leakage of these four cooling water hose assembly connection parts is detected by one IC tag reader 40.

  FIG. 6 is a block diagram showing the configuration of the IC tag 13, and FIG. 7 is a block diagram showing the configuration of the IC tag reader 40.

  As shown in FIG. 6, the IC tag 13 includes an antenna 31, a rectifier 32, a demodulator 33, a modulator 34, a memory 35, and a control unit 36. The electromagnetic wave that reaches the antenna 31 is converted into an alternating current by an inductance of the antenna 31 itself and a capacitor (not shown) connected in parallel with the inductance, and is input to the rectifier 32. The rectifier 32 converts the input alternating current into a direct current having a predetermined voltage, and outputs this as a driving current. The demodulator 33, the modulator 34, and the control unit 36 are operated by this drive current.

  In the memory 35, an ID code (identification code) unique to the IC tag 13 is recorded. The demodulator 33 demodulates the signal received via the antenna 31 and outputs the demodulated signal to the control unit 36. When receiving an ID code read command from the IC tag reader 40 via the demodulator 33, the control unit 36 reads the ID code from the memory 35 and outputs the ID code to the modulator 34. The modulator 34 modulates the ID code transmitted via the control unit 36 by superimposing it on the carrier wave, and outputs it as an electromagnetic wave from the antenna 31.

  On the other hand, the IC tag reader 40 includes an antenna 41, a transmitter 42, a receiver 43, and a control unit 45 as shown in FIG. The IC tag reader 40 is connected to the main control unit 50 as shown in FIG. Based on the signal from the main control unit 50, the control unit 45 issues an ID code read command and outputs it to the transmitter 42. The transmitter 42 modulates the ID code read command input from the control unit 45 by superimposing it on the carrier wave, and outputs it as an electromagnetic wave from the antenna 41.

  When receiving the electromagnetic wave transmitted from the IC tag 13 with the antenna 41, the receiver 43 extracts the ID code from the received electromagnetic wave and outputs the ID code to the control unit 45. The control unit 45 transfers the ID code acquired from the receiver 43 to the main control unit 50 (see FIG. 4).

  In the present embodiment, electromagnetic waves in the 13.56 MHz band are used for communication between the IC tag 13 and the IC tag reader 40. The electromagnetic wave in this frequency band can be attenuated by about 20 to 40 dB by a water-soluble conductive polymer film (electromagnetic shielding film 15) having a thickness of about 10 μm, for example, and has a characteristic that attenuation by moisture is relatively small. . In the present embodiment, the maximum communication distance between the IC tag 13 and the IC tag reader 40 is about 1.0 to 1.5 m.

  FIG. 8 is a flowchart showing the operation at the time of detecting a liquid leak. FIG. 9 is a schematic diagram showing a state in which the electromagnetic shielding film is dissolved and disappeared by the liquid leaked from the pipe.

  First, in step S11, the main control unit 50 outputs a liquid leakage inspection request signal to the IC card reader 40, for example, at regular intervals. When the controller 45 of the IC card reader 40 receives the liquid leakage inspection request signal from the main controller, it issues an ID code read command in step S12. As a result, the transmitter 42 of the IC tag reader 40 superimposes the IC code read command on the carrier wave and outputs it from the antenna 41 as an electromagnetic wave.

  Thereafter, the process proceeds to step S13, and the control unit 45 of the IC card reader 40 determines whether or not an ID code is received. When there is no liquid leakage at the connecting portion between the hose 11 and the joint fitting 12, the electromagnetic wave output from the IC card reader 40 is attenuated by the electromagnetic shielding film 15 disposed around the connecting portion and reaches the IC tag 13. For this reason, the IC tag 13 does not operate, and the ID code is not transmitted to the IC card reader 40. In this case, the process returns from step S13 to step S11.

  On the other hand, when a liquid leak occurs, the leaked liquid travels through the porous sheet 16 and contacts the electromagnetic shielding film 15 as shown in FIG. As a result, the electromagnetic shielding film 15 dissolves and disappears in water, and the electromagnetic wave from the IC card reader 40 reaches the IC tag 13 with almost no attenuation. The electromagnetic shielding film 15 does not have to disappear completely. It is only necessary that a part of the electromagnetic shielding film 15 disappears and the electromagnetic wave reaches the IC tag 13 from the IC card reader 40.

  When a sufficiently strong electromagnetic wave reaches the IC tag 13, power necessary for the operation of each part in the IC tag 13 is supplied from the rectifier 32, and the control unit 36, the demodulator 33, the modulator 34, and the memory 35 start operating. To do. Then, the control unit 36 reads the ID code from the memory 35 according to the ID code read command sent from the IC tag reader 40 and transmits the ID code to the IC tag reader 40 via the modulator 34 and the antenna 31.

  When receiving the ID code in step S13, the control unit 45 of the IC tag reader 40 proceeds to step S14 and outputs the ID code to the main control unit 50. When the main control unit 50 receives the ID code from the IC tag reader 40, the main control unit 50 proceeds to step S15 and analyzes the ID code to identify the location where the liquid leakage has occurred. Then, the process proceeds to step S16, and an alarm is generated according to a preset program. Further, the main control unit 40 stops the supply of the cooling water to the device 20 and stops the operation of the device 20.

  In this embodiment, since the passive (non-power source) IC tag 13 is used as the liquid leakage sensor, the sensor is extremely small and no electrical wiring to the sensor is required. In addition, in the present embodiment, a plurality of liquid leakage sensors (IC tags 13) can be managed by one IC tag reader 40. Therefore, installation and maintenance of the sensor are easy.

  In the present embodiment, a unique ID code is assigned to each IC tag 13, and when the liquid leaks, the ID code is transmitted from the IC tag 13 to the main control unit 50 via the IC tag reader 40. The part 50 can easily identify the location where the liquid leakage has occurred.

  In the present embodiment, since the porous sheet 16 absorbs the liquid and diffuses, and thereby the electromagnetic shielding film 15 dissolves and disappears, the liquid leakage is detected, so that the liquid leakage is detected quickly and with high sensitivity. It can be detected and damage to the device due to liquid leakage can be prevented.

  Even when liquid leakage occurs from the connection portion, the cooling water is absorbed by the hygroscopic expansion material sheet 14 disposed on the end side of the porous sheet 16. Furthermore, since the gap between the pipe and the case 17 is closed by the expansion of the hygroscopic expansion material sheet 14, the outflow of the liquid to the outside can be prevented.

(Second Embodiment)
FIG. 10 is a diagram showing a liquid leakage inspection method according to the second embodiment. This embodiment is different from the first embodiment in that the electromagnetic shielding film 15 is formed so as to cover the surface of the IC tag 13. Since the other configuration is basically the same as that of the first embodiment, the description of the overlapping parts is omitted. In FIG. 10, the same components as those in FIG. 3 are denoted by the same reference numerals.

  In the present embodiment, an IC tag 13 covered with an electromagnetic shielding film 15 is attached to a connection portion between the hose 11 and the joint fitting 12. Further, a porous sheet 16 is wound around the IC tag 13 and the connection portion. A case 17 made of a resin film is wound around the porous sheet 16.

  In the present embodiment, when a liquid leak occurs from the pipe, the leaked liquid is absorbed and diffused by the porous sheet 16. The electromagnetic shielding film 15 on the surface of the IC tag 13 dissolves and disappears by contact with the liquid absorbed by the porous sheet 16. As a result, communication between the IC tag 13 and the IC tag reader 40 becomes possible, and liquid leakage can be detected.

(Other embodiments)
In each of the first and second embodiments described above, the case has been described in which liquid leakage from the piping of the cooling water used for cooling the device having the heat source is detected. However, the first or second embodiment has been described. The structure can be applied to chemical leakage such as acid or alkali, or leakage of piping for transferring an organic solvent.

  For example, when applied to a liquid leak in a pipe for transferring an organic solvent, the electromagnetic shielding film 15 can be a conductive polymer material film having high solubility in the organic solvent. In this case, since the electromagnetic shielding film 15 is dissolved in the organic solvent and disappears when the electromagnetic shielding film 15 comes into contact with the leaked organic solvent, the signal transmitted from the IC tag reader 40 is reliably transmitted to the IC tag 13. To reach.

  In addition, for example, when applied to a liquid leak in a pipe for transferring acid or alkali, the electromagnetic shielding film 15 may be a material that loses conductivity by reacting with acid or alkali.

  DESCRIPTION OF SYMBOLS 10 ... Hose assembly, 11 ... Hose, 12 ... Fitting metal fitting, 13 ... IC tag (RFID), 14 ... Hygroscopic expansion material sheet, 15 ... Electromagnetic shielding film, 16 ... Porous sheet, 17 ... Case, 18 ... Moisture-proof film, DESCRIPTION OF SYMBOLS 20 ... Apparatus which has a heat source, 21 ... Cooling water hose assembly attachment port, 22 ... Fixture, 31 ... Antenna, 32 ... Rectifier, 33 ... Demodulator, 34 ... Modulator, 35 ... Memory, 36 ... Control part, 40 ... IC tag reader, 41 ... antenna, 42 ... transmitter, 43 ... receiver, 45 ... control unit, 50 ... main control unit.

Claims (6)

An IC tag and a porous sheet that absorbs and diffuses the liquid leaked from the pipe are arranged around the pipe through which the liquid passes,
A conductor film that disappears in contact with the liquid in a portion in contact with the porous sheet is disposed so as to surround the IC tag,
An IC tag reader antenna is arranged on the opposite side of the IC tag across the conductor film,
A liquid leak detection method, wherein the presence or absence of a liquid leak is determined by detecting the presence or absence of an electromagnetic wave output from the IC tag by the IC tag reader.   The liquid leak detection method according to claim 1, further comprising a case covering the porous sheet, wherein the conductive film is formed on the case.   The liquid leakage detection method according to claim 1, wherein the conductor film is formed on a surface of the IC tag.   The liquid leakage detection method according to claim 1, wherein the conductor film is made of a water-soluble conductive polymer material. An IC tag arranged around the pipe;
A porous sheet that is arranged around the pipe where the IC tag is arranged and absorbs and diffuses the liquid flowing in the pipe;
A conductor film disposed so as to surround the periphery of the IC tag in a portion in contact with the porous sheet, and disappears by contact with the liquid;
An IC tag reader having an antenna disposed on the opposite side of the IC tag across the conductor film;
A main control unit connected to the IC tag reader,
The main control unit determines whether or not there is a liquid leak from the pipe according to a communication state between the IC tag reader and the IC tag. The main control unit requests an ID code from the IC tag via the IC tag reader,
The liquid leak detection system according to claim 5, wherein a liquid leak location is specified by the ID code sent from the IC tag.

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