JP2020067351A - Heat insulating material - Google Patents

Abstract

To provide a heat insulating material capable of performing nondestructive inspection for reduction in thickness, a crack or the like of an inspection target such as a pipe, a container or the like covered with a heat insulating material, without attachment/detachment.SOLUTION: A heat insulating material 40 covers the periphery of an inspection target 41 that becomes high in temperature. Inside the heat insulating material 40, at least one magnetic field line converging structure 1 is provided in a cross-sectional direction of the heat insulating material 40 for one sensor coil 22 connected to a sensor 20 arranged on the surface of the inspection target 41 for inspecting the inspection target 41. Further, one magnetic field line converging structure 1 is provided without straddling two sensor coils 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat insulating material used to heat a structure such as a pipe on which a nondestructive inspection is performed.

  Regarding a wireless sensor suitable for non-destructive inspection of a test object, as an example of a small, lightweight, and simple wireless sensor, Patent Document 1 discloses that a converter and an enclosing portion are configured to be electrically connected to the converter. An electrically conductive transducer coil coupled to the transducer to enable the transducer to be inductively actuated by a remote device, the enclosure defined by the transducer coil being associated with the transducer. It has a larger internal width dimension than the width dimension of

GB25232266 publication

C. Zhong, A. Croxford, P. Wilcox, “Investigation of Inductively Coupled Ultrasonic Transducer System for NDE” IEEE transactions on ultrasonics, Vol.60, No.6 (2013) pp.1115-1125

  The non-destructive inspection technology is a technology that can inspect the state of an object without destroying it. In particular, non-destructive inspection using ultrasonic waves is used in a wide range of fields because of its low cost and easy application.

  In nuclear power plants and thermal power plants, ultrasonic crack inspections and wall thickness inspections are regularly performed to ensure the integrity of pipes and containers.

  Most of the target pipes and containers are covered with heat insulating material. Therefore, for ultrasonic inspection, it is necessary to first remove the heat insulating material, manually press the ultrasonic probe to a predetermined inspection point for inspection, and then restore the heat insulating material. If the inspection location is high, scaffold assembly is required before and after the inspection.

  Particularly in a nuclear power plant, it is stipulated that a large number of pipes and containers are inspected at every periodic inspection, which requires a lot of labor and time. Further, in the above-described manual inspection, the signal received by the ultrasonic probe changes depending on the pressing angle of the ultrasonic probe, etc. Therefore, it is necessary to carefully control the ultrasonic probe for each inspection point.

  In order to solve such a problem, there is a method of attaching a battery and an ultrasonic sensor having a radio wave transmitter / receiver for control to the inspection point in advance. Accordingly, it is possible to control each ultrasonic sensor from the control server at the time of inspection and automatically perform ultrasonic inspection at each inspection point. Further, by attaching an ultrasonic sensor in advance under the heat insulating material, it becomes possible to ultrasonically inspect the pipe and the container without attaching or detaching the heat insulating material.

  However, with this method, it is necessary to attach a battery and a radio wave transmitter / receiver for control to the ultrasonic sensor, and periodic maintenance such as battery replacement is required. There is also a problem that the sensor itself becomes large.

  In addition, an inspection method using an ultrasonic optical probe in which an electromagnetic ultrasonic transmitter and an optical fiber sensor are combined is known. An optical fiber sensor detects a resonant wave of ultrasonic waves excited by an electromagnetic ultrasonic wave transmitter. By installing the electromagnetic ultrasonic oscillator and the optical fiber sensor in advance at the inspection point under the heat insulating material, it is possible to perform ultrasonic inspection of the pipe without attaching or detaching the heat insulating material.

  However, since the power supply line and the signal line are drawn from each electromagnetic ultrasonic oscillator and the optical fiber sensor, a large number of wirings are required, and there is a problem that the risk of disconnection increases. Also, if the sensor detects cracks or thinning in the pipe, it is necessary to remove the heat insulating material and move to detailed inspection manually, but the power line and signal line of the sensor are pulled out through the heat insulating material to the outside. Therefore, there is a problem that it is necessary to disconnect the power supply line and the signal line to remove the heat insulating material, and it becomes impossible to use even the sensor of the portion that does not require detailed inspection.

  The above-mentioned Patent Document 1 describes a method of performing non-contact ultrasonic inspection using electromagnetic induction between coils. In this method, a sensor and a sensor coil connected to the sensor are installed in advance on an inspection target, and information is exchanged between the sensor and the sensor probe through a magnetic field generated by electromagnetic induction from a sensor probe including a transmission coil and a reception coil. Then, ultrasonic inspection is performed without contact.

  The method described in Patent Document 1 is considered to be a promising technique because the sensor unit is composed of only the sensor and the sensor coil, so that no battery is required and the sensor unit is maintenance-free.

  Here, in a nuclear power plant, regular inspection of many pipes and containers is required. Especially in the pipe thinning inspection, in Japan, the inspection method recommended by the Japan Society of Mechanical Engineers is defined. Among them, the measurement pitch on the surface of the pipe is required to be 100 mm or less.

  According to this standard, many sensors will be attached to the surface of the pipe, so it is important that the sensors themselves are maintenance-free and compact. Compared with the conventional inspection method, the inspection method utilizing the electromagnetic induction between the coils described in Patent Document 1 is considered to be effective because the sensor section is maintenance-free and compact.

  However, in the method described in Patent Document 1, in order to obtain sufficient information transmission by electromagnetic induction, it is necessary to use a coil having an outer diameter substantially the same as the inter-coil distance. On the other hand, as described above, the measurement pitch for pipe thinning is specified in advance, so there is a limitation on the usable coil size. Therefore, there is a problem that it is difficult to perform measurement through a heat insulating material having a thickness equal to or larger than the outer diameter of the coil used.

  Further, when the measurement pitch is narrow, the method described in Patent Document 1 has a problem that signals are received from adjacent sensor coils when the sensor probe is inspected from above the heat insulating material.

  The present invention has been made in view of the above problems, and its object is to have a thickness preferably equal to or greater than the outer diameter of the coil, and to be covered by a heat insulating material such as a pipe or a container to be inspected. It is an object of the present invention to provide a heat insulating material that enables non-destructive inspection of thinning and cracks of structures without attachment / detachment.

  The present invention includes a plurality of means for solving the above problems, but if one example is given, it is a heat insulating material that covers the periphery of a structure having a high temperature, and the structure is provided inside the heat insulating material. At least one magnetic force line converging member is provided in a cross-sectional direction of the heat insulating material for one sensor coil connected to a sensor arranged on the surface of the structure for inspection. To do.

  According to the present invention, it is possible to perform nondestructive inspection of a structure covered by a heat insulating material, such as a pipe or a container, for thinning or cracking of a structure to be inspected without attaching or detaching. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a figure which shows the structure of the heat insulating material and sensor system which concern on Example 1 of this invention. It is a figure which shows the outline of the operating principle of the sensor system in the system in which the heat insulating material of the well-known art for comparison was used. It is a figure which shows the outline of the operation principle of the sensor system in the system using the heat insulating material of Example 1 of this invention. It is a figure which shows an example of the received waveform obtained by the sensor system in the system by which the heat insulating material of the well-known technique for comparison was arrange | positioned. It is a figure which shows another example of the received waveform obtained by the sensor system in the system by which the heat insulating material of the well-known technology for comparison was arrange | positioned. It is a figure which shows an example of the received waveform obtained by the sensor system in the system by which the heat insulating material of Example 1 of this invention was arrange | positioned. It is a figure which shows another example of a structure of the heat insulating material and the sensor system which concern on Example 1 of this invention. It is the figure which looked at a heat insulating material and a partial composition of a sensor system concerning Example 2 of the present invention from the sensor probe side. It is the figure which looked at the detailed structure of the heat insulating material which concerns on Example 2 of this invention from the sensor probe side. It is the figure which looked at the detailed structure of the heat insulating material which concerns on Example 3 of this invention from the sensor probe side. It is a figure which shows the structure of the heat insulating material and sensor system which concern on Example 4 of this invention. It is a figure which shows the assembling method of the magnetic force line converging structure with respect to the heat insulating material which concerns on Example 4 of this invention. It is a figure which shows the structure of the heat insulating material and sensor system which concern on Example 5 of this invention. It is a figure which shows the structure of the heat insulating material and sensor system which concern on Example 6 of this invention.

  Examples of the heat insulating material of the present invention will be described below with reference to the drawings.

<Example 1>
Example 1 of the heat insulating material of the present invention will be described with reference to FIGS. 1 to 7.

  First, the relationship between the heat insulating material and the sensor system and the configuration thereof will be described with reference to FIG. FIG. 1 is a cross-sectional view showing the configurations of the heat insulating material and the sensor system according to the first embodiment.

  In the embodiment shown in FIG. 1, the sensor system includes a sensor 20 attached to the surface of an inspection target 41, a cable 21, a sensor coil 22 electrically coupled to the sensor 20 via the cable 21, a sensor coil 22 and the inspection target. The sensor probe 32 is composed of an electromagnetic wave shielding sheet 23, a transmission coil 31 and a reception coil 30 which are arranged between 41.

  An electric signal corresponding to a transmission wave generated by a pulser (not shown) is converted into a magnetic field by electromagnetic induction in the transmission coil 31, and is transmitted to the sensor coil 22 via the magnetic flux 3. In order to prevent the magnetic field generated by the transmission coil 31 from being lost as an eddy current on the surface of the inspection target 41, the electromagnetic wave shielding sheet 23 is installed between the sensor coil 22 and the inspection target 41.

  As the electromagnetic wave shielding sheet 23, for example, EMI Absorber AB Series manufactured by US 3M Co. is used. The thickness of the electromagnetic wave shielding sheet 23 is 0.2-0.5 [mm] to sufficiently exhibit the shielding performance, but a thicker sheet may be used.

  The electric signal received by the sensor coil 22 is transmitted to the sensor 20 through the cable 21.

  A piezoelectric element is used for the sensor 20 to generate ultrasonic waves. The size of the piezoelectric element is determined by the frequency of the ultrasonic wave used, but in this embodiment, the outer diameter is 10 [mm] and the thickness is 0.6 [mm]. The material of the piezoelectric element used is, for example, NCE51 manufactured by Noliac of Denmark.

  In the present embodiment, the sensor 20 is a piezoelectric element in order to generate ultrasonic waves, but the sensor 20 may be composed of other sensors such as a strain gauge, an electromagnetic sensor, an accelerometer, and a heat sensor.

  The transmission coil 31 and the reception coil 30 of the sensor probe 32 are connected to a pulser / receiver (not shown) used for normal ultrasonic inspection and a PC (not shown) having an oscilloscope function.

  The transmission coil 31, the reception coil 30, and the sensor coil 22 are, for example, flat coils each formed of a copper wire of 0.05 [mm]. The size and the number of turns are determined by the method described in Non-Patent Document 1, for example.

  The larger the coil outer diameter, the higher the SN ratio (Signal to Noise ratio) of the signal received by the receiver. However, as described above, the pipe thinning inspection requires a measurement pitch of 100 [mm] or less.

  Therefore, in consideration of the interference between the adjacent sensor coils 22, the outer diameter of the sensor coil 22 is set to 30 [mm] in this embodiment. The outer diameters of the transmission coil 31 and the reception coil 30 are set to 53 [mm] and 46 [mm], respectively, in consideration of the SN ratio and the interference of adjacent coils.

  However, the present invention is not limited to the illustrated dimensions, and can be appropriately changed depending on the shape of the inspection target, the required SN ratio, and the like.

  The inspection target 41 in the present embodiment is a metal plate made of carbon steel or stainless steel, and corresponds to a pipe or container having a large curvature in the plant inspection. The inspection object 41 is covered with a heat insulating material 40 made of calcium silicate (or made of rock wool, glass wool, amorphous water kneaded, hard urethane foam, or the like) because it becomes hot during plant operation.

  As shown in FIG. 1, the heat insulating material 40 of the present embodiment is a member that keeps the temperature of the inspection target 41 by covering the periphery of the inspection target 41 that becomes high temperature, and the magnetic force line converging structures 1a and 1b are included therein. , (Hereinafter referred to as magnetic force line converging structure 1) are arranged. These magnetic force line converging structures 1 are rod-shaped members provided so as to penetrate from the heat insulating material inner surface 42 side to the heat insulating material outer surface 43 side.

  The cutout portion 10 is provided on the heat insulating material 40 side of the heat insulating material 40 as a space in which the sensor 20, the sensor coil 22, and the like are arranged.

  The magnetic force line converging structure 1 is made of, for example, a magnetic material (for example, ferrite), and has a rod shape penetrating from the heat insulating material inner surface 42 side to the heat insulating material outer surface 43 side.

  There is no restriction on the cross-sectional shape of the magnetic force line convergence structure 1, and it may be circular or quadrangular. It is desirable that the outer diameter of the magnetic force line converging structure 1a be at least 1/10 of the outer diameter of the sensor coil 22.

  As shown in FIG. 1, the magnetic force line converging structure 1 has one heat insulating material for one sensor coil 22 connected to the sensor 20 arranged on the surface of the inspection object 41 to inspect the inspection object 41. It is provided in the direction of the cross section of 40. The magnetic force line converging structure 1 may be arranged so that at least a part thereof is included in the vertical region 2 of the sensor coil 22 arranged on the inspection target 41.

  Further, one magnetic force line converging structure 1 is arranged in the heat insulating material 40 without straddling the two sensor coils 22.

  The magnetic force line converging structure 1a is arranged with a predetermined space (hereinafter, referred to as magnetic field line converging structure space 70) from the adjacent magnetic force line converging structure 1b.

  The magnetic force line converging structure 1 is preferably made of a material having a relatively low thermal conductivity for the purpose of ensuring the performance of the heat insulating material 40. Although the specific value of the thermal conductivity of the magnetic force line converging structure 1 is not unconditionally determined depending on factors such as the sectional shape of the magnetic force line converging structure 1 and the heat insulating performance required for the heat insulating material 40, the heat insulating material 40 It is desired that the thermal conductivity is about 10 times or less, and particularly a magnetic material. As a result, it is possible to suppress the increase in the amount of heat radiation due to the additional installation of the magnetic force line converging structure 1 without impairing the heat insulating performance of the heat insulating material 40, and more reliably exhibit the performance of the heat insulating material.

Further, the magnetic force line converging structure 1 is required to have a characteristic that the magnetic flux reaches from the heat insulating material inner surface 42 side of the heat insulating material 40 to the heat insulating material outer surface 43 side and from the heat insulating material outer surface 43 side to the heat insulating material inner surface 42 side. It is desirable that the magnetic permeability is high, and even if it is not, it is desirable that the magnetic permeability is 1 × 10 ⁻⁴ [H / m] or more, particularly a magnetic material.

  FIG. 2 is a diagram for explaining the operation principle of the sensor system in the system using the conventional heat insulating material, and FIG. 3 is a diagram for explaining the operation principle of the sensor system in the system in which the heat insulating material of this embodiment is arranged. It is a figure.

  In the conventional technique shown in FIG. 2, in order for the magnetic field generated in the transmission coil 31 to reach the sensor coil 22 with sufficient strength, the outer diameter is approximately the same as the distance between the transmission coil 31 and the sensor coil 22. It has been experimentally found that it is necessary to use a coil. Therefore, under the condition that the temperature of the inspection target 41 is high and the heat insulating material 140 is thick as shown in FIG. 2, it is necessary to use a coil having a size equal to the thickness of the heat insulating material 140.

  On the other hand, since the arrangement interval (measurement pitch) of the sensors 20 is defined by the inspection method recommended by the Japan Society of Mechanical Engineers, the outer diameter of the sensor coil 22 is unlimited so that the magnetic field reaches the sensor coil 22 with sufficient strength. However, there is a problem that it cannot be increased. This is the case in Japan, but there are inspection methods recommended for each country in the world, and similarly, it is difficult to increase the outer diameter of the sensor coil 22 without limitation.

  Therefore, when the outer diameter of the sensor coil 22 is limited, in the case of the thick heat insulating material 140, the magnetic flux 3 generated in the transmission coil 31 does not reach the sensor coil 22 and measurement is performed, as is clear from FIG. There is a problem that you cannot do it.

  On the other hand, in order to transmit the magnetic flux 3 to the sensor coil 22 with sufficient strength, it is necessary to reduce the thickness of the heat insulating material 140 and bring the transmitting coil 31 closer to the sensor coil 22. However, the thickness of the heat insulating material 140 is specified in order to suppress heat radiation from the pipes and the like under the heat insulating material 140, and it is difficult to reduce the thickness of the heat insulating material 140.

  On the other hand, as shown in FIG. 3, in the present invention, the magnetic force line converging structure 1 is arranged in the heat insulating material 40. Further, at least one or more magnetic force line converging structures 1 are provided in the cross-sectional direction of the heat insulating material 40 for one sensor coil 22 connected to the sensor 20 arranged on the surface of the inspection target 41.

  Therefore, even when a coil having an outer diameter smaller than the thickness of the heat insulating material 40 is used for the transmission coil 31 and the sensor coil 22, the magnetic flux 4 generated in the transmission coil 31 passes through the magnetic force line converging structure 1. It passes through and reaches the sensor coil 22.

  Thereby, it becomes possible to perform the measurement without reducing the thickness of the heat insulating material 40. Further, since the sensor coil 22 and the magnetic force line converging structure 1 can be arranged close to each other, a sensor coil 22 having a small outer diameter can be used, and even when the measurement pitch 71 is narrow, such as a pipe thinning inspection. The ultrasonic inspection can be performed without receiving the signal from the adjacent sensor coil 22.

  Furthermore, for example, in a nuclear power plant or a thermal power plant, when attaching a heat insulating material to piping (for example, when newly installing or when desorption is required during replacement work or inspection, etc.), it is described in this Example 1. According to the heat insulating material 40 having the magnetic force line converging structure 1 always on the sensor coil 22 as described above, the relative positional relationship between the magnetic force line converging structure 1 and the sensor coil 22 changes before and after mounting the heat insulating material 40. Instead, the effect of transmitting the magnetic flux between the transmitter coil 31 and the receiver coil 30 and the sensor coil 22 by the magnetic force line converging structure 1 is maintained. Therefore, when ultrasonically probing the inspection target 41 such as a pipe or a container covered with the heat insulating material 40 having a thickness equal to or larger than the outer diameter of the sensor coil 22 in a non-contact manner, a signal between the sensor coil 22 and the sensor probe 32. Communication is possible.

  Therefore, even if the relative positional relationship between the sensor coil 22 and the magnetic force line converging structure 1 changes when the heat insulating member 40 is attached and detached, the magnetic force line converging structure 1 is reliably arranged on the sensor coil 22, and therefore the heat insulating member 40 The magnetic flux 4 is transmitted to the sensor coil 22 regardless of the relationship with the thickness of the sensor coil 22.

  4 and 5 show a sensor system in a system in which a heat insulating material of a known technique disclosed in Non-Patent Document 1 is arranged (a method of performing non-contact ultrasonic inspection using electromagnetic induction between coils). It is a figure which shows the received waveform (bottom echo) obtained by (1), and FIG. 6 is a figure which shows the received waveform obtained by the sensor system in the system by which the heat insulating material of this invention was arrange | positioned.

  Regarding the coil size, as described above, the outer diameter of the sensor coil is 30 [mm], the outer diameter of the transmitting coil is 53 [mm], and the outer diameter of the receiving coil 30 is 46 [mm]. The distance to the sensor coil 22 (described as a non-contact measurement distance in the figure) was 15 [mm] in FIG. 4 and 40 [mm] in FIGS. 5 and 6.

  As can be seen from FIG. 4, when the non-contact measurement distance is smaller than the coil outer diameter, the signal is received with sufficient strength. Further, as can be seen from FIG. 5, the signal intensity decreases when the non-contact measurement distance increases.

  On the other hand, as shown in FIG. 6, in the measurement according to the present invention, it is understood that the signal is received with sufficient strength even when the non-contact measurement distance is large with respect to the coil outer diameter.

  Since the sensor 20 is electrically coupled to the sensor coil 22 via the cable 21, the electric signal received by the sensor coil 22 causes the sensor 20 to vibrate, and ultrasonic waves are transmitted into the inspection target 41.

  The ultrasonic waves reflected by the crack or the bottom surface of the inspection target 41 and received by the sensor 20 cause the sensor 20 to generate an electric signal by the piezoelectric effect. This electric signal is received by the receiving coil 30 via the magnetic flux 4 from the sensor coil 22, and is displayed on the oscilloscope on the PC through the receiver.

  Therefore, the inspector can determine the presence or absence of cracks in the inspection target 41, the amount of thinning, and the like from the displayed waveform, and perform the ultrasonic inspection of the inspection target 41 without attaching or detaching the heat insulating material 40. Can be done.

  In addition, when the inspection object 41 is located at a high place, by attaching a long bar for high-altitude inspection to the sensor probe 32, ultrasonic inspection can be performed without scaffolding assembly, and the sensor 20 is previously inspected. Since it is attached, it is not necessary to carefully control the ultrasonic probe for each inspection point, and the inspection time can be shortened.

  Further, since the sensor probe 32 and the sensor coil 22 are coupled to each other through the electromagnetic induction phenomenon, energy is supplied to the sensor 20 from the sensor probe 32 through the magnetic field in a non-contact manner, so that the sensor 20 is attached to the inspection target 41. The sensor 20, the sensor coil 22, and the magnetic force line converging structure 1 attached to the heat insulating material 40 do not need to be provided with a mechanical connecting portion. That is, the sensor section does not need an energy source such as a battery, and the sensor section is compact and maintenance-free.

  In addition, since it is not necessary to mechanically connect the sensor cable, when the sensor 20 detects a crack or thinning, the heat insulating material 40 is removed and the sensor cable is disconnected even when the manual detailed inspection is performed. The heat insulating material 40 can be removed without doing so.

  As described above, according to the method described in Patent Document 1, since the inspection target is covered with the heat insulating material after the sensor and the sensor coil are installed on the surface of the inspection target, the position of the sensor coil cannot be visually recognized, and the sensor probe is not used during the inspection. There is a problem that it is difficult to match the position of the sensor coil.

  On the other hand, by using the heat insulating material 40 in which the magnetic force line converging structure 1 is arranged as in the present embodiment, the magnetic force line converging structure 1 exists at the position of the sensor coil 22, so that the sensor probe 32 and the sensor coil 22 can be easily provided. Can be aligned.

  In addition, since one magnetic force line converging structure 1 is provided without straddling the two sensor coils 22, it is possible to suppress interference from the adjacent sensor coils 22 and more reliably perform the inspection of the target portion. can do.

Further, the magnetic force line converging structure 1 is made of a magnetic material, and the magnetic permeability of the magnetic force line converging structure 1 is 1 × 10 ⁻⁴ [H / m] or more, so that the electromagnetic induction phenomenon can be more reliably conducted. The sensor probe 32 and the sensor coil 22 can be coupled to each other, and the performance of the heat insulating material 40 can be sufficiently ensured.

  Further, since the magnetic force line converging structure 1 is disposed inside the vertical range of the corresponding one sensor coil 22, the distance for disposing the magnetic force line converging structure 1 can be shortened and the heat insulating material 40 can be provided. The effect as described above can be obtained while further securing the performance.

  Further, the magnetic force line converging structure 1 is a rod-shaped member provided so as to penetrate from the inner peripheral surface side to the outer peripheral surface side of the heat insulating material 40, so that the heat insulating material inner surface 42 side to the heat insulating material outer surface 43 can be reliably performed. The lines of magnetic force can be connected to the heat insulating material outer surface 43 side to the heat insulating material inner surface 42 side, and the above-described effect can be more reliably obtained.

  As shown in FIG. 1, the magnetic force line converging structure 1 is arranged straight in the heat insulating material 40 from the heat insulating material outer surface 43 side to the heat insulating material inner surface 42 side so that the vertical range of the corresponding one sensor coil 22 is increased. The arrangement is not limited to the case of being arranged inside, but may be arranged obliquely as shown in FIG. 7.

  Also in this case, by using the magnetic force line converging structure 1e corresponding to the sensor coil 22 arranged on the left side in FIG. 7 instead of the magnetic force line converging structures 1d and 1f, the sensor probe and the sensor coil are separated from each other as described above. It is coupled through the phenomenon of electromagnetic induction. Therefore, even if the inspection target is provided with a heat insulating material having a thickness equal to or larger than the outer diameter of the coil, ultrasonic inspection can be performed without attaching or detaching the heat insulating material.

<Example 2>
A heat insulating material of Example 2 of the present invention will be described with reference to FIGS. 8 and 9. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The same applies to the following examples.

  FIG. 8 is a view of a partial configuration of the heat insulating material and the sensor system according to the second embodiment as viewed from the sensor probe side, and is a view showing a positional relationship between the sensor coil and the magnetic force line converging structure. 9: is the figure which looked at the detailed structure of the heat insulating material which concerns on Example 2 from the sensor probe side, and is a figure which shows the relative positional relationship of one sensor coil 22a and the magnetic force line converging structure arrange | positioned in the vicinity. is there.

  As shown in FIG. 8, in this embodiment, when the heat insulating material 40A is viewed from the outer surface side, the sensor coils 22a to 22d are arranged in a square shape at the measurement pitch 71 on the surface of the inspection object 41.

  Therefore, the magnetic force line converging structure 1 is arranged inside the heat insulating material 40A in a quadrangular shape, more specifically in a square shape, with the magnetic force line converging structure space 70 being maintained.

  Here, the magnetic force line converging structure interval 70 refers to the distance on the outer surface of the inspection target (in the case of piping, refers to the distance on the piping surface). Note that the sensor coils 22a to 22d and the magnetic force line converging structures 1 are not limited to the numbers shown in FIG.

  In order to increase the non-contact measurement distance without increasing the outer diameter 72 of the sensor coils 22a to 22d, at least one magnetic force line converging structure 1 is provided on each of the sensor coils 22a to 22d. You can place it in.

  Therefore, even if the positional relationship between the inspection object 41 such as the pipe and the heat insulating material is changed because the magnetic force line converging structure intervals 70 of all the magnetic force line converging structures 1 are installed within a certain upper limit distance, it is more preferable. One or more magnetic force line converging structures 1 are surely arranged on the sensor coils 22a to 22d without fail, and the required non-contact measurement distance can be secured.

As shown in FIG. 9, the magnetic force line converging structures 1a to 1d have a minimum configuration of a square arrangement. In order for at least one of the magnetic force line focusing structures 1a to 1d to be located on the sensor coil 22a, the magnetic force line focusing structures 1a to 1d are arranged on the outer circumference of the sensor coil 22a as shown in FIG. It is necessary to secure the converging structure interval 70 as the upper limit distance. Therefore, if the outer diameter 72 of the sensor coil 22a is D _S1 [m], the magnetic force line converging structure interval 70 (P _M1 [m]) is expressed by the following equation (1).

  From the above, the relative positional relationship between the sensor coil 22 and the magnetic force line converging structures 1a1 to 1d1 was changed by using the heat insulating material 40A provided with the magnetic force line converging structures 1a1 to 1d1 satisfying the expression (1) in advance. However, the magnetic force line converging structures 1a1 to 1d1 are always arranged in the region on the sensor coil 22.

  The other configurations and operations are substantially the same as the configurations and operations of the heat insulating material 40 of the first embodiment described above, and details thereof will be omitted.

  Also in the heat insulating material 40A of the second embodiment of the present invention, substantially the same effect as that of the heat insulating material 40 of the above-described first embodiment can be obtained.

  The number of sensor coils 22 in this embodiment may be one or more.

  Further, the sensor coils 22a to 22d do not have to be arranged in a square shape, but may be arranged in a rectangular shape, a staggered arrangement, or an irregular arrangement. The magnetic force line converging structures 1a1 to 1d1 do not have to be arranged in a square and may be arranged in a rectangle. When the magnetic force line converging structures 1a1 to 1d1 are arranged in a rectangular shape, it is desirable that the formula (1) be applied to the magnetic force line converging structure intervals corresponding to the long sides.

<Example 3>
A heat insulating material of Example 3 of the present invention will be described with reference to FIG.

  FIG. 10 is a diagram showing the detailed configuration of the heat insulating material according to the third embodiment as viewed from the sensor probe side, and is a diagram showing a relative positional relationship between one sensor coil and magnetic force line converging structures arranged in a staggered arrangement in the vicinity thereof. Is.

  As shown in FIG. 10, in this embodiment, the magnetic force line converging structures 1a2 to 1d2 are arranged in a square shape which is the minimum configuration of the staggered arrangement.

  In the third embodiment, the configuration of the sensor coil 22a is the same as that of the second embodiment, and only the differences will be described below. The magnetic force line converging structures 1a2 to 1d2 are arranged in a zigzag arrangement inside the heat insulating material, and are arranged on the outer circumference of the sensor coil 22a.

  The magnetic force line converging structure intervals 70a and 70b are intervals corresponding to diagonal lines of a square, respectively, and both are equal intervals in FIG.

  In order to reliably position at least one of the magnetic force line focusing structures 1a2 to 1d2 on the sensor coil 22a in the present embodiment, as shown in FIG. 10, the magnetic force line focusing structures 1a2 to 1d2 are provided on the outer periphery of the sensor coil 22a. It is necessary to secure, as the upper limit distance, the magnetic force line converging structure intervals 70a and 70b such that

Therefore, assuming that the magnetic force line focusing structure intervals 70a and b are P _M2 [m] and the outer diameter 72 of the sensor coil 22a is D _S2 [m], at least one magnetic force line focusing structure is located on the sensor coil 22a. P _M2 [m] is represented by the following equation (2).

  From the above, it is assumed that the relative positional relationship between the sensor coil 22 and the magnetic force line converging structures 1a2 to 1d2 is changed by using the heat insulating material provided with the magnetic force line converging structures 1a2 to 1d2 satisfying the expression (1) in advance. Also, the magnetic force line focusing structures 1a2 to 1d2 are always arranged in the region on the sensor coil 22.

  The other configurations and operations are substantially the same as the configurations and operations of the heat insulating material 40 of the first embodiment described above, and details thereof will be omitted.

  Also in the heat insulating material of Example 3 of the present invention, substantially the same effect as that of the heat insulating material 40 of Example 1 described above can be obtained.

  Also in this embodiment, the sensor coils 22a to 22d do not have to be arranged in a square shape, but may be arranged in a rectangular shape, a staggered arrangement, or an irregular arrangement.

  Further, the magnetic force line converging structures 1a2 to 1d2 do not have to be a staggered array formed of squares, and may be a rhombus arrangement in which the magnetic force line converging structure spaces 70a and 70b are not equal. In the case of the zigzag arrangement in which the magnetic force line converging structures 1a2 to 1d2 are formed in a rhombus, it is desirable that the expression (2) is applied to the magnetic force line converging structure space corresponding to the longer one of the two diagonal lines.

<Example 4>
A heat insulating material according to Example 4 of the present invention will be described with reference to FIGS. 11 and 12. 11: is a figure which shows the structure of the heat insulating material which concerns on Example 4. FIG. FIG. 12 is a diagram showing a method of incorporating the magnetic force line converging structure into the heat insulating material according to the fourth embodiment of the present invention.

  In a nuclear power plant or a thermal power plant, a fluid (water, steam, etc.) flowing in a pipe sometimes wears a constituent material of the pipe and causes wall thinning. The Japan Society of Mechanical Engineers defines a recommended pipe thinning inspection method, and requires that the measurement pitch be 100 [mm] or less. This embodiment assumes such a target.

  As shown in FIG. 12, the sensor system according to the present embodiment includes a sensor 20, which is attached to the surface of a pipe 44 to be inspected, a cable 21, and a sensor coil 22 which is electrically coupled to the sensor 20 via the cable 21. It is composed of a sensor probe (not shown) composed of a transmission coil and a reception coil.

  The pipe 44 to be inspected has a high temperature during the operation of the plant, and is therefore covered with a heat insulating material 40B made of calcium silicate (or made of rock wool, glass wool, amorphous water, hard urethane foam, etc.).

  The magnetic force line converging structure 1 is arranged so as to penetrate the heat insulating material inner surface 42B and the heat insulating material outer surface 43B, and the configuration thereof is the same as that described in the first embodiment.

  As described above, the magnetic force line converging structure 1 is arranged on the heat insulating material 40B and does not need to be mechanically coupled to the sensor 20 and the sensor coil 22 on the pipe 44 to be inspected.

  Therefore, as shown in FIG. 12, the heat insulating material 40B and the magnetic force line converging structure 1 can be manufactured in an integral structure. As a result, it is not necessary to embed the magnetic force line converging structure 1 in the heat insulating material on site, and the manufacturability is improved.

  In the pipe thinning inspection, it is necessary to remove the heat insulating material at the place where there is a sign of thinning, and shift to the detailed measurement to measure at a denser measurement pitch. In the case of an example, as shown in FIG. 12, the heat insulating material 40B can be removed only at a necessary portion.

  The other configurations and operations are substantially the same as the configurations and operations of the heat insulating material 40 of the first embodiment described above, and details thereof will be omitted.

  Also in the heat insulating material 40B of the fourth embodiment of the present invention, substantially the same effect as that of the heat insulating material 40 of the first embodiment described above can be obtained.

<Example 5>
A heat insulating material according to Example 5 of the present invention will be described with reference to FIG. FIG. 13 is a diagram showing the configurations of the heat insulating material and the sensor system according to the fifth embodiment.

  Examples of inspection targets of the sensor system as described above include plant pipes and containers. When the inspection target has a high temperature, in the heat insulating material 40 described in the first embodiment, the magnetic force line converging structure 1 penetrates the heat insulating material 40, so that the heat radiation through the magnetic force line converging structure 1 is further reduced. By taking measures, it is possible to secure more heat retention performance. In the present embodiment, such a high temperature inspection target is assumed.

  As shown in FIG. 13, in the present embodiment, the sensor system includes a sensor 20 attached to the surface of the inspection target 41, a sensor coil 22 electrically coupled to the sensor 20 via a cable 21, a sensor coil and the inspection. The sensor probe 32 is composed of the electromagnetic wave shielding sheet 23, the transmission coil 31, and the reception coil 30 arranged between the targets 41.

  Further, as shown in FIG. 13, the heat insulating material 40C of the present embodiment has a rod-shaped magnetic force line converging structure 5 embedded therein.

  The magnetic force line converging structure 5 in the present embodiment does not project to the heat insulating material outer surface 43C or the heat insulating material inner surface 42C, does not penetrate the heat insulating material 40C, and is embedded in the heat insulating material 40C. At the time of embedding, a filling port 6 is provided on the outer surface 43C of the heat insulating material, and the magnetic force line converging structure 5 is embedded in the heat insulating material 40C from there. In addition, an embedding port may be provided on the inner surface 42C of the heat insulating material, and the magnetic force line converging structure 5 can be embedded from there.

  The material and shape of the magnetic force line focusing structure 5 can be substantially the same as those of the magnetic force line focusing structure 1 described in the first embodiment. The arrangement can be the same as in the second and third embodiments.

  The distance from the upper end of the magnetic force line converging structure 5 to the heat insulating material outer surface 43C and the distance from the lower end of the magnetic force line converging structure 5 to the heat insulating material inner surface 42C sufficiently obtain the effect of converging the magnetic flux from the transmission coil 31. Therefore, it is desirable that the value is at least less than or equal to the diameter of the magnetic force line convergence structure 5.

  Further, a part of the magnetic force line converging structure 5 is arranged so as to be included in the vertical region 2 of the sensor coil 22 arranged on the inspection target 41.

  The other configurations and operations are substantially the same as the configurations and operations of the heat insulating material 40 of the first embodiment described above, and details thereof will be omitted.

  Also in the heat insulating material 40C of Example 5 of the present invention, substantially the same effect as that of the heat insulating material 40 of Example 1 described above can be obtained.

  Further, the size of the heat flux that causes the heat radiation from the inspection target 41 is determined by the thickness of the heat insulating material 40C in the transmission path. Therefore, the magnetic force line converging structure 5 is a rod-shaped member embedded inside the heat insulating material 40C, so that the magnetic flux from the transmitting coil 31 is converged while suppressing the heat radiation from the inspection target 41 which becomes high temperature. The effect can be obtained.

  In addition, although the case where the magnetic force line converging structure 5 does not project from both the heat insulating material outer surface 43C and the heat insulating material inner surface 42C has been described with reference to FIG. It can be arranged so as to project from either side.

<Example 6>
A heat insulating material according to Example 6 of the present invention will be described with reference to FIG. FIG. 14 is a diagram showing the configurations of the heat insulating material and the sensor system according to the sixth embodiment.

  Similar to the fifth embodiment, the present embodiment aims to further secure the heat retaining performance by taking measures to further reduce the heat radiation through the magnetic force line converging structure.

  As shown in FIG. 14, in the heat insulating material 40D of the present embodiment, the rod-shaped magnetic force line converging structure is provided inside the heat insulating material 42D side and the heat insulating material outer surface 43D side and is coaxially divided. Objects 7 and 8 are embedded.

  In the structure in which the magnetic force line converging structure 5 is embedded inside the heat insulating material 40C as in the fifth embodiment described above, when the position of the magnetic force line converging structure 5 is not clearly indicated, the sensor probe 32 and the sensor are used during the inspection. It is desirable to take some measures to match the position with the coil 22.

  On the other hand, in the present embodiment, since the heat retaining material outer surface side magnetic force line converging structure 7 and the heat retaining material inner surface side magnetic force line converging structure 8 are used, the heat retaining material outer surface side is suppressed while suppressing the heat radiation from the inspection target 41 which becomes high temperature. Since the magnetic force line converging structure 7 functions as a mark, the sensor probe 32 and the sensor coil 22 can be easily aligned during inspection.

  The distance between the facing ends of the heat insulating material outer surface side magnetic force line converging structure 7 and the heat insulating material inner surface side magnetic force line converging structure 8 is at least a value equal to or smaller than the diameter of the magnetic force line converging structure in order to sufficiently obtain the effect of magnetic flux convergence. Is desirable.

  Other materials, shapes, etc. regarding the magnetic force line focusing structures 7 and 8 may be the same as those of the magnetic force line focusing structure 1 described in the first embodiment. The arrangement can be the same as in the second and third embodiments.

  The other configurations and operations are substantially the same as the configurations and operations of the heat insulating material of the first embodiment described above, and details are omitted.

  Also in the heat insulating material 40D of the sixth embodiment of the present invention, substantially the same effect as that of the heat insulating material 40 of the above-described first embodiment can be obtained.

  Further, the magnitude of the heat flux that causes the heat radiation from the inspection object 41 is determined by the thickness of the heat insulating material 40D in the transmission path. Therefore, the magnetic force line converging structures 7 and 8 are formed on the inner surface side and the outer surface of the heat insulating material 40D. By being configured by a rod-shaped member that is divided on the side and coaxially provided, it is possible to obtain the effect of converging the magnetic flux from the transmission coil 31 while suppressing the heat radiation from the inspection target 41 that becomes high temperature. You can

  Note that, when the heat insulating material 40D is viewed from the outer surface side, the case where the heat insulating material outer surface side magnetic force line converging structure 7 and the heat insulating material inner surface side magnetic force line converging structure 8 have the same vertical positional relationship has been described. The heat insulating material outer surface side magnetic force line converging structure 7 and the heat insulating material inner surface side magnetic force line converging structure 8 do not have to be completely coincident with each other, and at least a part of the heat insulating material 40D may overlap when viewed from the outer surface side. desirable.

<Other>
It should be noted that the present invention is not limited to the above-described embodiments, but includes various modifications. The above embodiments have been described in detail for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described.

  Further, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. It is also possible to add / delete / replace other configurations with respect to a part of the configurations of the respective embodiments.

1, 1a, 1b, 1c, 1d, 5: Magnetic force line focusing structure (magnetic force line focusing member)
2: Vertical regions 3, 4: Magnetic flux 6: Embedding port 7: Heat insulating material outer surface side magnetic force line converging structure 8: Heat insulating material inner surface side magnetic force line converging structure 10: Notch 20: Sensor 21: Cables 22, 22a, 22b , 22c, 22d: sensor coil 23: electromagnetic wave shielding sheet 30: receiving coil 31: transmitting coil 32: sensor probe 40, 46: heat insulating material 41: inspection target (structure)
42: Heat insulating material inner surface 43: Heat insulating material outer surface 44: Pipes 70, 70a, 70b: Interval 71: Measurement pitch 72: Outer diameter

Claims (11)

A heat insulating material that covers the periphery of a structure that becomes hot,
Inside the heat insulating material, at least one magnetic flux converging member is provided for the heat insulating material for one sensor coil connected to a sensor arranged on the surface of the structure for inspecting the structure. A heat insulating material characterized by being provided in the cross-sectional direction. The heat insulating material according to claim 1,
A heat insulating material, wherein one magnetic force line converging member is provided without straddling the two sensor coils. The heat insulating material according to claim 1,
The magnetic force line converging member is provided in a quadrangular shape when the heat insulating material is viewed from the outer surface side,
A heat insulating material, wherein an arrangement interval of the magnetic force line converging members corresponding to one side of a quadrangle is set to (2 ^1/2 ) / 2 times or less of a diameter of the sensor coil. The heat insulating material according to claim 1,
The magnetic force line converging member is provided in a quadrangular shape when the heat insulating material is viewed from the outer surface side,
A heat insulating material, wherein an arrangement interval of the magnetic force line converging members corresponding to a diagonal line of a quadrangle is configured to be equal to or less than a diameter of the sensor coil. The heat insulating material according to claim 3 or 4,
The heat insulating material, wherein the magnetic force line converging member is provided in a square shape. The heat insulating material according to claim 1,
The heat insulating material, wherein the magnetic force line converging member is made of a magnetic material. The heat insulating material according to claim 1,
The heat insulating material, wherein the magnetic force line converging member has a magnetic permeability of 1 × 10 ⁻⁴ [H / m] or more. The heat insulating material according to claim 1,
The heat insulating material, wherein the magnetic force line converging member is arranged inside a vertical range of the corresponding one of the sensor coils. The heat insulating material according to claim 1,
The heat insulating material is a rod-shaped member provided so as to penetrate from the inner peripheral surface side to the outer peripheral surface side of the heat insulating material. The heat insulating material according to claim 1,
The heat insulating material, wherein the magnetic force line converging member is a rod-shaped member embedded inside the heat insulating material. The heat insulating material according to claim 1,
The heat insulating material, wherein the magnetic force line converging member is composed of a rod-shaped member that is divided into an inner surface side and an outer surface side of the heat insulating material and is provided coaxially.

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