JP4405066B2 - Fluid leak detection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluid leakage detection system that detects fluid leakage that occurs due to breakage of cracks, pits, or the like in high-temperature and high-pressure piping installed in a reactor containment vessel, for example.
[0002]
[Prior art]
For example, Japanese Patent Laid-Open No. Sho 54-86816 discloses a technique for early detection of damage caused by stress corrosion cracking of a welded portion of a high-temperature high-pressure pipe in a nuclear power plant. In the technique described in this publication, a steam reservoir is provided outside the pipe, and a steam detection element is provided in the steam reservoir.
[0003]
With reference to FIG. 23, a conventional fluid leak detection system from piping in a nuclear power plant reactor containment vessel will be described. In FIG. 23 (a), reference numeral 1 denotes a reactor containment vessel. A reactor pressure vessel 2 is installed in the reactor containment vessel 1, and a pipe 3 through which high-temperature and high-pressure fluid flows is connected to the reactor pressure vessel 2. Has been. An air cooler 4 is provided in the reactor containment vessel 1, and this air cooler 4 is connected to a drain sump 6 provided at the bottom of the reactor containment vessel 1 by a drain pipe 5. An atmosphere monitor 7 and a leak detection device 8 are provided outside the reactor containment vessel 1, and the leak detection device 8 is connected to the atmosphere monitor 7 and the drain sump 6 by a signal line 9. As shown in FIG. 23 (b), the pipe 3 has a configuration in which a stainless steel pipe main body 11 is wrapped with a heat insulating material 12 and the heat insulating material 12 is wrapped with a heat insulating material cover 13.
[0004]
For example, when cracks or pits occur in the piping 3 connected to the reactor pressure vessel 2 in the reactor containment vessel 1 and the leakage of the high-temperature and high-pressure fluid occurs, the leakage detection is provided at the lower portion of the reactor containment vessel 1. In addition, the leak detection device 8 is activated and detected by increasing the amount of drain in the drain sump 6 or by increasing the radioactivity by the atmosphere monitor 7 in the reactor containment vessel 1.
[0005]
That is, when cracks and pits occur in the high-temperature and high-pressure pipe 3 and the high-temperature and high-pressure water leaks, the leaked high-temperature and high-pressure water first stays inside the heat insulating material cover 13. Detection by the drain sump 6 causes cracks to grow and increases the amount of leakage, and the steam is blown into the reactor containment vessel 1 as steam, and the water condensed by the air cooler 4 flows down through the drain pipe 5 and flows into the drain sump 6. Then, it becomes possible only when the leak detection device 8 is operated, and there is a time delay until leak detection.
[0006]
In the future, the concept of leakage confirmation before break (Leak-Before-Break: abbreviated as LBB) will be applied to breakage of high-temperature and high-pressure pipes. Therefore, there is a need for a system that can detect a minute amount of leakage at an early stage in order to safely stop the station.
[0007]
[Problems to be solved by the invention]
The conventional fluid leakage detection system associated with piping breakage in the reactor containment vessel has the following problems.
(1) While the high-temperature and high-pressure water leaked from the piping stays in the heat insulating material 12 inside the heat insulating material cover 13, the fluid leakage cannot be detected.
[0008]
(2) Even if leaked fluid flows out of the heat insulating material cover 13, the condensed water flows through the drain pipe 5 to the drain sump 6 under the reactor containment vessel 1 for the time that the steam reaches the air cooler 4. It takes time to detect that the drain flow rate has changed from the normal flow rate, and there is a time delay from the occurrence of leakage to the detection.
[0009]
(3) When the amount of fluid leakage is very small (about 4 liters per minute or less), the detection by the drain sump 6 has little change in the drain flow rate from the normal state. Can not.
[0010]
(4) Although the position where the breakage can be assumed by applying the LBB concept can be assumed, the breakage position cannot be identified by detecting the drain amount by the drain sump 6 under the reactor containment vessel 1.
(5) Leaks such as trace amounts of steam from pipes in nuclear power plants have been detected by human beings by sound and visual inspections every several hours.
[0011]
The present invention has been made in order to solve the above-described problems, and a small amount of fluid leakage that occurs due to minute breakage of the piping main body is detected at an early stage when the leaked fluid stays inside the heat insulating material cover. An object of the present invention is to provide a fluid leakage detection system that can safely detect and specify a breakage position.
[0012]
[Means for Solving the Problems]
The invention according to claim 1 is a leakage sensor which is an object that is provided on the surface of a heat insulating material cover that surrounds a pipe body that circulates a high-temperature fluid, and is melted and changed in shape by the temperature of the high-temperature fluid that has leaked out of the pipe body. And a solid piece attached to the leakage sensor and falling or moving due to a shape change of the leakage sensor .
[0013]
In the present invention, the fluid leakage traces generated with a very small damage to the piping main body, the movement and fall of the solid piece, early and secure at the stage where the fluid leaked is retained in the inside of the heat insulating material covering It is possible to detect the damage position and identify the breakage position.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A fluid leakage detection system of Reference Example 1 of the present invention is shown in FIG. That is, the pipe 3 of the high-temperature high-pressure fluid is wound heat insulating material, heat insulating material is heated by the leaked steam from the pipe, the temperature of the heat insulator cover 13 is raised to 70 ° C. to 100 ° C., the reference example Then, as shown in FIG. 1 (a), a strip-shaped detection line 16 having a structure as shown in FIG. The pipe 3 is wound around the outer periphery of the heat insulating material cover 13 in a spiral shape, and disconnection detectors 17 are connected to both ends. The disconnection detector 17 includes a low-voltage power source 18, a dummy resistor 19, and a voltmeter 20. For the metal wire 14, a low melting point alloy (for example, a wood metal U alloy) can be used.
[0015]
With this configuration, when the metal wire 14 is disconnected due to the heat of the steam leak, a voltage change occurs between both ends of the detection line 16, and the steam leak can be detected by detecting this voltage change with the disconnection detector 17. In addition, as in the present situation, the monitor can remotely detect the steam leak without approaching the vicinity of the pipe 3, and safety is improved.
[0016]
A fluid leakage detection system according to Reference Example 2 of the present invention is shown in FIG. That is, when the detection wire 16 is wound around the heat insulating material cover 13, it is easy to detect the vicinity of the cover connection portion 21 (FIG. 2A) where the steam leak of the pipe 3 is more likely to leak than the heat insulating material cover 13 or the steam leak. In this manner, the material is wound around the portion of the leakage hole 22 intentionally opened in the heat insulating material cover 13 (FIG. 2B). By doing so, it is possible to reduce the construction cost of steam leak detection and increase the detection accuracy, and the safety is further improved.
[0017]
FIG. 3 shows a fluid leakage detection system according to Reference Example 3 of the present invention. That is, as shown in FIG. 3 (b) or (c), a metal sheet 14 that is melted and disconnected by the heat of steam leakage is sandwiched between flat insulating sheets to form a detection sheet 23, which is shown in FIG. 3 (a). As shown in FIG. 4, the steam leak is detected by covering the connecting portion 21 or the leakage hole 22 of the heat insulating material cover 13. By doing so, it is possible to reduce the construction cost for steam leak detection and to improve the detection accuracy.
[0018]
Next, a fluid leakage detection system according to Reference Example 4 of the present invention will be described with reference to FIG. That is, as shown in FIG. 4A, a belt-like detection wire 24 that melts at 70 ° C. or more and deteriorates insulation is wound around the surface of the heat insulating material cover 13 that protects the heat insulating material of the pipe 3. As shown in FIG. 4B, the detection wire 24 is obtained by coating a metal wire 25 made of stainless steel or copper with a heat-meltable coating material 26. As shown in FIG. 4A, an insulation deterioration detector 27 is connected between the metal wire 25 of the detection wire 24 and the heat insulating cover 13. The insulation deterioration detector 27 includes a low-voltage power supply 28, a dummy resistor 29, and an ammeter 30.
[0019]
With this configuration, the covering material 26 is melted by the heat of the steam leak, the insulation resistance of the detection wire 24 is deteriorated, and the leakage current to the heat insulating material cover 13 changes. Thereby, a steam leak can be detected, and the steam leak can be detected remotely without approaching the vicinity of the pipe as in the present situation, thereby improving safety.
As the material of the covering material 26, a low melting point vinyl chloride resin can be used.
[0020]
FIG. 5 shows a fluid leakage detection system according to Reference Example 5 of the present invention.
That is, the detection wire 24 used in the reference example 4 is intentionally provided on the heat insulating material cover 13 so that the steam leakage of the pipe 3 is more likely to leak than the heat insulating material cover 13 or around the cover connecting portion 21. Wrapping around the site of the leak hole 22 opened in the center. By doing so, it is possible to reduce the construction cost of steam leak detection and increase the detection accuracy, and the safety is further improved.
[0021]
FIG. 6 shows a fluid leakage detection system according to Reference Example 6 of the present invention.
As shown in FIGS. 6B and 6C, a flat plate-shaped detection sheet 31 in which a metal wire 25 is coated with a heat-melting insulating coating material 26 that melts and degrades due to the heat of steam leakage is shown in FIG. As shown in a), the cover connecting portion 21 and the leakage hole 22 are covered to detect a vapor leak.
[0022]
A fluid leakage detection system according to Reference Example 7 of the present invention is shown in FIG.
That is, as shown in FIG. 7 (b), the detection wire 32 obtained by coating the parallel metal wire 33 made of two conductors with the heat-meltable coating material 26 is connected to the pipe 3 as shown in FIG. 7 (a). The insulation resistance detector 34 is connected to the parallel metal wire 33 of the terminal of the detection wire 32. According to this configuration, the coating material 26 is melted by the heat of the steam leak, the insulation between the parallel metal wires 33 is deteriorated, and the steam leak can be detected by the resistance change between the wires.
[0023]
The principal part of the fluid leakage detection system of Reference Example 8 of the present invention is shown in FIG. That is, in this reference example , the adhesive 38 is applied to one side of the detection lines 16 and 24 in the reference examples 1 and 4 or the detection sheets 23 and 31 in the reference examples 3 and 6 . With such a configuration, the detection line 16 and the like wound around the heat insulating material cover 13 are easily fixed, and the construction for detecting the steam leak becomes easy.
[0024]
Next, a fluid leakage detection system according to Reference Example 9 of the present invention will be described. That is, as described above, a heat insulating material is wound around the high-pressure pipe, and the surface temperature of the heat insulating material cover that protects the heat insulating material is heated by the steam leaked from the pipe, and is about 70 ° C. The temperature rises to about 100 ° C. In particular, the temperature around the connection portion of the heat insulating material cover increases. Therefore, in this reference example , a temperature indicating paint whose color changes between 70 ° C. and 100 ° C. is applied to the surface of the heat insulating material cover. As a result, the steam leak can be determined by the color, so that the steam leak can be detected remotely without going to the vicinity of the pipe as in the present situation, and safety is improved.
[0025]
FIG. 9 shows a cross-sectional view of the main part of the fluid leakage detection system of Reference Example 10 of the present invention. FIG. 9A is a normal time, and FIG. 9B is a diagram at the time of vapor leak. That is, the upper hole 41 and the lower hole 42 which are two kinds of holes having different diameters are connected, and the lower hole 42 penetrates from the lid under the container 43. As shown in FIG. 9A, an air bubble 44 and a paint 45 are placed inside the upper hole 41. As shown in FIG. 9A, the container 43 is attached so that the lower hole 42 faces downward. The paint 45 is held so as not to fall from the lower hole 42 due to the surface tension of the paint 45. The detector 40 configured in this manner is installed around the connection portion of the heat insulating material cover of the high-temperature high-pressure pipe. The paint 45 uses the color opposite to that of the heat insulating material cover.
[0026]
The surface temperature of the heat insulating material cover rises to 70 ° C. to 100 ° C. due to the steam leaking from the pipe. There accompanied to the temperature of the container 43 by the temperature rise is increased, the temperature of the air bubbles 44 also rises. The volume of the air bubbles 44 expands due to the temperature rise, and the paint 45 is pushed out from the lower hole 42 by this expansion as shown in FIG. Thereby, a steam leak can be determined.
[0027]
Next, FIG. 10 shows a fluid leakage detection system of Reference Example 11 of the present invention. This reference example includes a detection switch 46, a buzzer 47, and a microphone 48. The detection switch 46 includes a thermal deformation plate 49, a + electrode 50, a −electrode 51, and an insulating material 52 made of bimetal or shape memory alloy.
[0028]
In normal times, as shown in FIG. 10, the + electrode 50 and the thermal deformation plate 49 are separated from each other. That is, the detection switch 46 is in an OFF state. When steam leaks in the pipe, the temperature of the detection switch 46 rises, the thermal deformation plate 49 is deformed, the + electrode 50 and the plate 49 come into contact, and the detection switch 46 is turned on. This ON signal is transmitted to the buzzer 47, and the buzzer 47 makes a sound. By detecting this sound with the microphone 48, steam leak can be detected.
[0029]
FIG. 11 shows a fluid leakage detection system of Reference Example 12 of the present invention. In this reference example , a receiving antenna 53 is added to the reference example 11 . In this reference example , the microphone 48 transmits when a vapor leak is detected based on the same principle as in the reference example 11 . The transmitted signal is detected by the receiving antenna 53. In a nuclear power plant, there are many pipes, and it is necessary to detect where the steam leak occurred without getting close to the site, but according to this reference example , the frequency of the sound from the buzzer 47 is changed. Thus, the location of the steam leak can be specified.
[0030]
Next, a fluid leakage detection system according to Reference Example 13 of the present invention will be described with reference to FIG. That is, the blow-off 55 is attached to the surface of the heat insulating material cover 13, and the leak hole 54 is opened, and the leak vapor 56 is blown out from the leak hole 54, and the blow-off 55 is shaken. As a result, it is possible to determine the leaked steam 56 and to detect the breakage of the pipe remotely without going to the vicinity of the pipe as in the present situation.
[0031]
Next, Reference Example 14 of the present invention will be described with reference to FIG. That is, a heat-meltable material 57 having a melting point of 70 ° C. to 100 ° C., for example, wax is adhered to the surface of the heat insulating material cover 13. With this configuration, the temperature of the heat insulating material cover 13 rises due to the leak, and the attached hot-melt material 57 melts, so that the leak can be detected. If colored wax or the like is used as the hot-melt material 57, the color spreads, so that leak detection is easier. In addition, since no other device such as a power supply is required and it is easy to install at many places, if a large number of places are installed, it is easy to identify the leak place.
[0032]
Next, a fluid leakage detection system according to an embodiment of the present invention will be described with reference to FIG. That is, a leak detector 58 made of a metal piece, a resin piece or the like is attached to the surface of the heat insulating material cover 13 of the pipe using a hot-melt material 57 having a melting point of 70 ° C. to 100 ° C. such as wax as an adhesive. According to this configuration, since the hot-melt material 57 melts together with the leak in the pipe, the adhered leak detector 58 drops or moves. Thereby, leak detection becomes possible. By making the leak detector 58 a conspicuous color, leak detection becomes easier. In addition, since no other device such as a power source is required and it is easy to install at many locations, it is easy to identify the leak location by installing many devices.
[0033]
Next, a fluid leakage detection system of Reference Example 15 of the present invention will be described with reference to FIG. As described above, when steam leaks from the high-temperature and high-pressure pipe 3, the outer surface temperature of the heat insulating material cover 13 rises to nearly 100 ° C. Therefore, a temperature-sensitive liquid crystal sheet 59 having a discoloration range in a temperature range of 50 ° C. to 100 ° C. is pasted on the outer surface of the heat insulating material cover 13. When the pipe 3 leaks, the color of the liquid crystal changes, so that the leak detection and the position can be specified. The temperature-sensitive liquid crystal sheet 59 may be directly applied as a temperature-sensitive liquid crystal paint. Further, it is known that the temperature difference of the temperature-sensitive liquid crystal is about 20 ° C., and the temperature range can be adjusted.
[0034]
Next, a fluid leakage detection system of Reference Example 16 of the present invention will be described with reference to FIG. This reference example further includes a camera 60, a repeater 62, and a computer 63 in addition to the configuration of the reference example 14, the embodiment of the present invention or the reference example 15 , and remotely performs leak detection and leak position specification. System. The heat-meltable material 57, the leak detector 58, and the temperature-sensitive liquid crystal sheet 59 provided on the surface of the heat insulating material cover 13 change in state due to a temperature rise accompanying the leak of the pipe 3. Therefore, the leak is detected by periodically monitoring these marks. A plurality of landmarks are photographed at regular intervals as an image, and it can be determined from the comparison with the last photographed image that a leak has occurred when the difference is large.
[0035]
A modification of Reference Example 16 of the present invention will be described below with reference to FIG. That is, a change or movement of a sensor such as a hot-melt material 57 is photographed by a CCD camera 64, compressed by an MPEG image compressor 65, periodically transmitted to a maintenance center 68 using a PHS transmitter 66, and received by a PHS. By calculating the difference between the two time images received by the machine 67 using the image calculation device 69, the vapor leak is detected, the alarm device 70 is sounded, and the alarm lamp is turned on. As a result, it is possible to quickly and accurately detect a steam leak in the primary system of a remote nuclear power plant or the like. In addition, the CCD camera 64, the image compression device 65, and the PHS transmitter 66 can be installed in large numbers on the order of 10,000 units, and the alarm lamp blinks on the graphic display panel showing the location of the sensor. The leak location can be quickly identified.
[0036]
Next, Reference Example 17 of the present invention will be described with reference to FIG. That is, the steam leaked from the high-temperature and high-pressure pipe passes through the gap between the pipe body and the heat insulating material, the gap in the heat insulating material, and the gap between the heat insulating material and the heat insulating material cover, and from the gap near the connection part 21 of the heat insulating material cover. Although leaking outside, as shown in FIG. 18A, a sound generation hole 73 is provided near the connecting portion 21 where steam is more likely to leak than the gap of the connecting portion. The sound generation hole 73 is formed so that a sound 72 is generated when the steam passes. The sound 72 detects a steam leak. Similarly, as shown in FIG. 18B, by providing the sound generation hole 73 in a portion other than the connection portion of the heat insulating material cover 13, it is possible to detect a vapor leak from other than the vicinity of the connection portion of the heat insulating material cover. Furthermore, by providing a plurality of sound generating holes 73 along the axial direction or circumferential direction of the pipe, the probability that leaked steam will pass through the sound generating holes is increased, and a larger sound, ultrasonic wave or high frequency 72 is generated, The leak position can be accurately detected.
[0037]
19 and 20 show Reference Example 18 of the present invention. That is, the heat collecting material 74 or the heat insulating material cover 13 is provided with air collecting holes 74 that guide the leaked vapor to the sound generating hole 73. As a result, the probability that the steam passes through the sound generating hole 73 is increased, and a larger sound, ultrasonic wave or high frequency is generated, and the steam leak position can be detected more accurately.
[0038]
FIG. 21 shows a cross-sectional view of the main part of the fluid leakage detection system of Reference Example 19 of the present invention. When steam leaks from the pipe, the surface temperature of the heat insulating material cover 13 rises to about 100 ° C. In particular, the temperature around the connection portion 21 of the heat insulating material cover 13 rises, and steam is generated. In the case of a large amount of steam leak, the leaked steam leaks directly from the connection portion 21. Therefore, in the present reference example , a small hole 75 is provided in the connection portion 21 of the heat insulating material cover 13, and a steam or steam detector 76 using infrared rays is provided above the small hole 75. As a result, it is possible to detect a steam leak remotely without going to the vicinity of the pipe as in the present situation, and safety is improved.
[0039]
Next, a fluid leakage detection system of Reference Example 20 of the present invention will be described with reference to FIG. In this reference example , a leak detector 77 having a power supply unit 78 and a control unit 79 is provided on the surface of the heat insulating material cover 13 of the pipe. The power supply unit 78 includes a p-type semiconductor 80 and an n-type semiconductor 81. The control unit 79 receives electric power from the power supply unit 78, activates the sensor, and issues an alarm signal. As described above, when the p-type semiconductor 80 and the n-type semiconductor 81 junction are provided as the thermoelectric generator on the heat insulating material cover 13 side of the leak detector 77, power is generated by the heat from the heat insulating material cover 13 side. The electromotive force of this thermoelectric generator is used as a power source. Usually, the surface temperature of the heat insulating material cover 13 is 50 ° C., and power can be generated by a temperature difference from the atmospheric temperature. As a result, the leak detector 77 requires almost no maintenance and is highly reliable. Further, when the steam leaks, the surface temperature of the heat insulating material cover rises, so that the electromotive force increases. Therefore, it is possible to detect this and issue an alarm.
Note that a photovoltaic element may be used for the power supply unit 78 when there is light such as illumination around the pipe.
[0040]
【The invention's effect】
According to the present invention, the occurrence of fluid leakage due to pipe breakage can be detected at an early stage in a very small amount, the location where the breakage has occurred can be identified, and the combined use with the conventional detection system can be multiplexed. Can be In the unlikely event that a pipe breaks, the operation of the pipe can be stopped earlier and at a safe stage.
[Brief description of the drawings]
FIG. 1 is a diagram showing a main part of a fluid leakage detection system of Reference Example 1 of the present invention.
FIG. 2 is a diagram showing a main part of a fluid leakage detection system of Reference Example 2 of the present invention.
FIG. 3 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 3 of the present invention.
FIG. 4 is a diagram showing a main part of a fluid leakage detection system of Reference Example 4 of the present invention.
FIG. 5 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 5 of the present invention.
FIG. 6 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 6 of the present invention.
FIG. 7 is a diagram showing a main part of a fluid leakage detection system according to a seventh embodiment of the present invention.
FIG. 8 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 8 of the present invention.
FIG. 9 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 10 of the present invention.
FIG. 10 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 11 of the present invention.
FIG. 11 is a diagram showing a main part of a fluid leakage detection system according to a reference example 12 of the present invention.
FIG. 12 is a diagram showing a main part of a fluid leakage detection system according to a reference example 13 of the present invention.
FIG. 13 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 14 of the present invention.
FIG. 14 is a diagram showing a main part of a fluid leak detection system of implementation of the present invention.
FIG. 15 is a diagram showing a main part of a fluid leakage detection system according to a reference example 15 of the present invention.
FIG. 16 is a diagram showing a main part of a fluid leakage detection system according to a reference example 16 of the present invention.
FIG. 17 is a diagram showing a main part of a fluid leakage detection system according to a modification of Reference Example 16 of the present invention.
FIG. 18 is a diagram showing a main part of a fluid leakage detection system according to a reference example 17 of the present invention.
FIG. 19 is a diagram showing a main part of a fluid leakage detection system according to a reference example 18 of the present invention.
FIG. 20 is a diagram showing a main part of a fluid leakage detection system according to a reference example 18 of the present invention.
FIG. 21 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 19 of the present invention.
FIG. 22 is a diagram showing a main part of a fluid leakage detection system according to Reference Example 20 of the present invention.
FIG. 23 is a diagram showing a conventional fluid leakage detection system in a nuclear power plant.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Reactor containment vessel, 2 ... Reactor pressure vessel, 3 ... Piping, 4 ... Air cooler, 5 ... Drain piping, 6 ... Drain sump, 7 ... Atmosphere monitor, 8 ... Leak detection device, 9 ... Signal line, 11 ... Pipe body, 12 ... Heat insulation, 13 ... Heat insulation cover, 14 ... Metal wire, 15 ... Insulation, 16 ... Detection wire, 17 ... Disconnection detector, 18 ... Low voltage power supply, 19 ... Dummy resistor, 20 ... Voltmeter , 21 ... Cover connection part, 22 ... Leakage hole, 23 ... Detection sheet, 24 ... Detection line, 25 ... Metal wire, 26 ... Cover material, 27 ... Insulation deterioration detector, 28 ... Low-voltage power supply, 29 ... Dummy resistor, 30 ... ammeter, 31 ... sensing sheet, 32 ... sensing wire, 33 ... parallel metal wire, 34 ... insulation resistance detector, 35 ... low voltage power supply, 36 ... dummy resistor, 37 ... ammeter, 38 ... adhesive, 40 ... sensing 41 ... Upper hole, 42 ... Lower hole, 43 ... Container, 44 ... Air bubbles, 45 ... Paint, 46 ... Detection switch, 47 ... Buzzer, 48 ... Microphone, 49 ... Thermal deformation plate, 50 ... + electrode, 5 1 ...- electrode, 52 ... insulating material, 53 ... receiving antenna, 54 ... leak hole, 55 ... blown, 56 ... leak vapor, 57 ... hot-melt material, 58 ... leak detector, 59 ... temperature-sensitive liquid crystal sheet, 60 ... Camera, 61 ... Camera view, 62 ... Repeater, 63 ... Computer, 64 ... CCD camera, 65 ... MPEG image compressor, 66 ... PHS transmitter, 67 ... PHS receiver, 68 ... Maintenance center, 69 ... Image Arithmetic unit, 70 ... alarm device, 72 ... sound, ultrasonic wave or high frequency, 73 ... sound generation hole, 74 ... collection hole, 75 ... small hole, 76 ... infrared detector, 77 ... leak detector, 78 ... power supply unit, 79: control unit, 80 ... p-type semiconductor, 81 ... n-type semiconductor.

Claims (1)

A leakage sensor that is provided on the surface of a heat insulating material cover that surrounds the piping main body that circulates the high-temperature fluid, is an object that melts and changes shape due to the temperature of the high-temperature fluid leaked outside the piping main body, and is attached to the leakage sensor And a solid piece that falls or moves due to a shape change of the leak sensor .

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