JP6547994B1 - Distortion detection device - Google Patents

Abstract

Provided is a distortion detection device capable of suppressing a measurement error of distortion of a detection object. The strain detection device 1 includes a breakage detection main member 11 having a small diameter portion 114 that can be broken when a tensile stress is applied in the first direction D0, a conduction portion 131 provided at a portion straddling the thin diameter portion 114, and a breakage. A first holding member 12A that holds the first end of the detection main member 11 and a second holding member 12B that holds the second end of the breakage detection main member 11 are provided. The first end portion and the second end portion each have a contact portion 115, and the first holding member 12A and the second holding member 12B each have a contacted portion 126 that faces the contact portion 115, The contact portion 115 is installed on the detected body in a state of being separated from the contacted portion 126.

Description

  The present invention relates to a distortion detection apparatus.

  Conventionally, there is known a strain detection device which is provided on the surface of a measurement object and detects strain by breakage of a detection unit (for example, Patent Document 1). Specifically, the strain detection device described in Patent Document 1 includes a thin film substrate attached to the surface of the measurement object, and a sensor foil provided on the thin film substrate. The sensor foil has a narrow easy-to-break portion at the center in the longitudinal direction. When the object to be measured is distorted, the sensor foil extends in the longitudinal direction and the easily breakable part breaks, thereby detecting the distortion.

International Publication WO2008 / 013049

  However, when the strain detection device is attached when the temperature of the object to be measured is low, the amount of strain when the temperature of the object to be measured is increased is the amount of strain due to thermal expansion as well as the amount of strain due to creep. It becomes a numerical value. As described above, in the strain measurement by the strain detection device described in Patent Document 1, a measurement error may occur due to the thermal expansion of the measurement object.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a strain detection device capable of suppressing measurement errors.

  The strain detection device according to the present invention is provided in a fracture detection main member having a fracture easy portion that can be fractured when a tensile stress is applied in a first direction, and a portion across the fracture easy portion in the fracture detection main member. A breakage detection unit, a first holding member fixed to the first part of the detection subject and holding the first end of the breakage detection main member, and a second part of the detection subject, the breakage detection And a second holding member for holding a second end of the main member, wherein the first end and the second end each have an abutting portion, and the first holding member and the second holding member And at least one of the first holding member and the second holding member, wherein the contact portion is separated from the contact portion in at least one of the first holding member and the second holding member. It is installed on the detection body.

  According to the present invention, distortion measurement error can be reduced.

FIG. 1: is a schematic diagram which shows the cross section of the boiler piping in which the distortion detection apparatus which concerns on 1st Embodiment of this invention, and the distortion detection apparatus was provided. FIG. 2 is a cross-sectional view taken along line II-II of FIG. FIG. 3 is an enlarged sectional view of a part of FIG. FIG. 4 is a perspective view of the breakage detection main member according to the first embodiment. FIG. 5 is a perspective view of the holding member according to the first embodiment. FIG. 6 is a cross-sectional view enlarging a part of FIG. 2 and shows a state in which the holding member moves. FIG. 7 is an enlarged sectional view of a part of the strain detection device according to the second embodiment. FIG. 8 is a schematic view of the distortion detection device according to the third embodiment as viewed from the upper side. FIG. 9 is a schematic view of the distortion detection device according to the fourth embodiment as viewed from the side. FIG. 10 is a schematic view showing a cross section of a to-be-detected body provided with a strain detection device and a strain detection device according to a fifth embodiment. FIG. 11 is a perspective view of a breakage detection main member according to a sixth embodiment. FIG. 12 is a schematic view of the distortion detection device according to the sixth embodiment as viewed from the upper side.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The disclosure is merely an example, and it is naturally included within the scope of the present invention as to what can be easily conceived of by those skilled in the art as to appropriate changes while maintaining the gist of the invention. In addition, the drawings may be schematically represented as to the width, thickness, shape, etc. of each portion in comparison with the actual embodiment in order to clarify the description, but this is merely an example, and the interpretation of the present invention is not limited. It is not limited.

  In the specification and the drawings, the same elements as those described above with reference to the drawings already described may be denoted by the same reference numerals, and the detailed description may be appropriately omitted. In the following description, the first direction D0 which is the extension direction of the detection target is also referred to as the longitudinal direction. In the first direction D0, the right direction in FIGS. 1 and 2 is referred to as a first extension direction D1, and the left direction in FIGS. 1 and 2 is referred to as a second extension direction D2.

First Embodiment
First, a first embodiment of the present invention will be described. FIG. 1 is a schematic view showing a cross section of a strain detection apparatus 1 according to a first embodiment of the present invention and a boiler pipe 2 (a detection target) provided with the strain detection apparatus 1.

  The strain detection device 1 according to the first embodiment is applied to, for example, detecting strain of a welded portion such as the boiler pipe 2 of a thermal power plant, but the target with which the strain detection device 1 detects strain is It is not limited to. That is, this embodiment will be described as an example in which the boiler pipe 2 is applied as a detection target. The boiler pipe 2 includes a first base material 21 (a first portion of a detected body), a second base material 22 (a second portion of the detected body), a first base material 21 and a second base material 22. And a welding portion 23 to be joined. The first base material 21 and the second base material 22 are, for example, high chromium ferritic steel pipes. Weld portion 23 includes weld metal 24 and heat affected zone 25. The weld metal 24 is, for example, a high chromium ferritic steel. The heat affected zone 25 is located between the first base material 21 and the weld metal 24. The heat affected zone 25 is a portion affected by heat when welding the first base material 21 and the second base material 22 using the weld metal 24. The heat affected zone 25 is different in mechanical properties and the like from the first base material 21, the second base material 22, and the weld metal 24. In the case of a metal member, a metal product or the like, when a state in which a constant load is applied continues for a long time, a creep phenomenon in which deformation of the metal member or the like increases may occur. In particular, since the welded portion 23 is easily broken due to the creep phenomenon, in the present embodiment, the welded portion 23 is used as a target portion of strain measurement.

  The strain detection device 1 is provided on the surface 2 a of the boiler pipe 2. Specifically, the strain detection device 1 extends along the extension direction (first direction D0) in the boiler pipe 2. The first holding member 12A and the second holding member 12B included in the strain detection device 1 are fixed to the surface 2a of the boiler pipe 2 by welding or the like. The first holding member 12A and the second holding member 12B are disposed straddling the welding portion 23. Specifically, the first holding member 12A is fixed to the first base material 21 (the first portion of the detection target). The second holding member 12B is fixed to the second base member 22 (second portion of the detection target).

  FIG. 2 is a cross-sectional view taken along line II-II of FIG. FIG. 3 is an enlarged sectional view of a part of FIG. FIG. 4 is a perspective view of the breakage detection main member 11 according to the first embodiment. FIG. 5 is a perspective view of the holding member 12 according to the first embodiment.

  As shown in FIG. 2, the strain detection device 1 includes a breakage detection main member 11, a first holding member 12 </ b> A and a second holding member 12 </ b> B, and a breakage detection device 13.

  As shown in FIG. 4, the breakage detection main member 11 includes a plurality of cylindrical portions having a central axis AX along the longitudinal direction. Specifically, the plurality of cylindrical portions have a large diameter portion 110A (first end), a large diameter portion 110B (second end), and a small diameter portion 111. The material of the breakage detection main member 11 can be made of ceramic which is easily broken easily.

  The large diameter portions 110A and 110B are end portions of the breakage detection main member 11 in the extension direction (first direction D0). Specifically, the first end portion disposed on the right side (first extension direction D1 side) in FIGS. 1, 2 and 4 is the large diameter portion 110A. The second end portion disposed on the left side (second extension direction D2 side) in FIGS. The large diameter portion 110A (first end) is held by the first holding member 12A. The large diameter portion 110B (second end) is held by the second holding member 12B. The large diameter portions 110 </ b> A and 110 </ b> B have a cylindrical portion 112 and a tapered portion 113. The cylindrical portion 112 is a cylinder of the same diameter extending in the longitudinal direction from the longitudinally outer edge 116 to the longitudinally central tip 117. The tapered portion 113 extends from the tip end 117 to the end edge 118 on the longitudinally central side.

  The tapered portion 113 has an outer diameter that increases in the first direction D0 (elongation direction). That is, in the tapered portion 113 on the right side of FIG. 4, the outer diameter increases in the first extension direction D1. In the tapered portion 113 on the left side of FIG. 4, the outer diameter increases in the second extension direction D2. The tapered portion 113 is an abutting portion 115 that can abut on an abutted portion 126 of a first holding member 12A and a second holding member 12B described later.

  The small diameter portion 111 extends in the longitudinal direction so as to connect the end edges 118 of the pair of tapered portions 113 separated in the longitudinal direction (first direction D0). The small diameter portion 111 is smaller in diameter than the cylindrical portion 112. The small diameter portion 111 has a small diameter portion 114 (easily fractured portion) locally formed with a small outer diameter. The small diameter portion 114 is a portion where the tips of a pair of truncated cone portions are joined together. The easily breakable portion may be, for example, a notch or a notch other than the small diameter portion 114.

  As shown in FIG. 2, the breakage detection device 13 has a conductive portion 131 (a breakage detection portion) and a detector 133 connected to the lead wire 132. The conductive portion 131 is a covering layer coated on the outer peripheral surface of the central portion in the longitudinal direction of the small diameter portion 111 including the small diameter portion 114 (the easily breakable portion). Conducting portion 131 is also referred to as a breakage detection portion. That is, the conducting part 131 (break detection part) is provided at a position across the small diameter part 114 (break easily part) in the breakage detection main member 11. The conducting portion 131 can be conducted and when the small diameter portion 114 is broken, the conducting portion 131 can also be broken together with the small diameter portion 114. The conducting part 131 is provided as a covering layer, for example, by thermal spraying or vapor deposition of a metal on the outer peripheral surface of the small diameter part 111. Two lead wires 132 are connected to both end portions in the longitudinal direction of the conduction portion 131, and the lead wires 132 are connected to the detector 133.

  Under normal conditions (when not broken), since the conductive part 131 is not broken, the current from the detector 133 energizes the conductive part 131 via one of the lead wires 132, and the other lead wire 132 to the detector 133. Return to In this case, it is determined that the breakage detection main member 11 is not broken. At the time of breakage of the conducting part 131, the breaking detection main member 11 is also broken together, so that the current from the detector 133 does not cause the conducting part 131 to conduct. It is detected that the breakage detection main member 11 is broken due to the current failure. As described above, in the breakage detection device 13, it is determined that the breakage detection main member 11 is broken when the conduction portion 131 (the breakage detection portion) is broken and a conduction failure occurs.

  As shown in FIG. 5, the first holding member 12A includes a base 121 and a lid 122. The first holding member 12A is fixed to the surface 2a of the boiler pipe 2 as shown in FIG. Specifically, the first holding member 12A is fixed to the surface 2a of the boiler pipe 2 positioned on both sides in the longitudinal direction of the welding portion 23 by welding or the like. As shown in FIG. 5, the base 121 is a box-like member, and a recess 123 is provided inside. The large diameter portion 110 </ b> A of the breakage detection main member 11 is accommodated in the concave portion 123. The upper opening is sealed by a lid 122 and fastened with a bolt or the like (not shown). As shown in FIG. 3, a U-shaped opening 124 is provided on the center side in the longitudinal direction (the front side in FIG. 5) of the inner peripheral surface of the recess 123. The second holding member 12B also has the same structure as the first holding member 12A.

  As shown in FIG. 3, the inner circumferential surface in the vicinity of the opening 124 is formed in the tapered portion 125. The tapered portion 125 has an inner diameter that increases in the first direction D0 (the first extension direction D1). The tapered portion 125 extends along the tapered portion 113 of the large diameter portion 110A. More specifically, the tapered portion 125 extends in parallel with the tapered portion 113 of the large diameter portion 110A. The tapered portion 125 is an abutted portion 126 disposed to face the abutting portion 115. In addition, the tapered portion 113 (contact portion 115) and the tapered portion 125 (contacted portion 126) are separated along the longitudinal direction. A gap G1 along the longitudinal direction is provided between the tapered portion 113 (contact portion 115) and the tapered portion 125 (contacted portion 126).

  Next, a change in relative position between the large diameter portion 110A of the fracture detection main member 11 and the first holding member 12A due to the movement of the first holding member 12A will be described. FIG. 6 is a cross-sectional view enlarging a part of FIG. 2, and shows a state in which the first holding member 12A moves.

  First, as shown in FIG. 1, an initial state in which the strain detection device 1 is fixed to the surface 2 a of the boiler pipe 2 will be described. As shown in FIG. 6, the radially inner end 126a of the abutted portion 126 of the first holding member 12A has a first position P1 along the longitudinal direction (first direction D0). At the first position P1, the tip end 126a of the abutted portion 126 is separated from the abutting portion 115 by the distance ds1 along the longitudinal direction.

  At this time, the end of the abutted portion 126 of the second holding member 12B shown on the left side of FIG. 1 and the end of the tip of the abutted portion 126 of the first holding member 12A shown on the right (tip 126a shown in FIG. The distance along the direction is L1. Although not shown in the present embodiment, the contact portion 115 and the abutted portion 126 abut each other in the second holding member 12B shown on the left side of FIG. In the first holding member 12A shown on the right side of FIG. 1, the abutting portion 115 and the abutted portion 126 are separated from each other.

  Next, when the boiler pipe 2 shown in FIG. 1 extends in the longitudinal direction, the distance between the first holding member 12A and the second holding member 12B also increases. Then, the tip end 126a of the abutted portion 126 shown in FIG. 6 moves in the first extension direction D1 by the distance ds1 and is positioned at the second position P2 indicated by the two-dot chain line. At the second position P2, the tip end 126a of the abutted portion 126 abuts on the abutting portion 115. At this time, the end of the abutted portion 126 of the second holding member 12B shown on the left side of FIG. 1 and the end of the tip of the abutted portion 126 of the first holding member 12A shown on the right (tip 126a shown in FIG. The distance along the direction is L2.

  When the boiler pipe 2 shown in FIG. 1 further extends in the longitudinal direction, the distance between the first holding member 12A and the second holding member 12B also increases. Then, the tip end 126a of the abutted portion 126 shown in FIG. 6 is further moved by a distance ds2 from the second position P2 in the first elongation direction D1, and is positioned at a third position P3 indicated by a broken line. In the third position P3, the tip of the abutted portion 126 of the second holding member 12B shown on the left side of FIG. 1 and the tip of the abutted portion 126 of the first holding member 12A shown on the right (the tip 126a shown in FIG. ) And the distance along the longitudinal direction is L3.

  Here, since the contact portion 115 and the contact portion 126 are in contact at the second position P2, the contact portion 115 of the fracture detection main member 11 is also extended in the extension direction by the distance ds2 from the second position P2. It moves in the (first elongation direction D1 side) and is located at a third position P3 indicated by a broken line. That is, at the third position P3, the amount of elongation along the longitudinal direction of the breakage detection main member 11 is the distance ds2. When the amount of elongation when the small diameter portion 114 of the breakage detection main member 11 breaks is set to the distance ds2, the breakage detection main member 11 breaks at the third position P3. Then, as described above, the conduction part 131 is also broken to cause a conduction failure, and the breakage detection device 13 detects that the breakage detection main member 11 is broken. In addition, since the first holding member 12A moves from the first position P1 to the third position P3, the total moving length is ds3 in which ds1 and ds2 are combined.

  As described above, in the strain detection device 1 according to the present embodiment, the first holding member 12A includes the abutted portion 126 opposed to the abutting portion 115 provided at the end of the breakage detection main member 11. Have. The abutting portion 115 and the abutted portion 126 are installed in the boiler pipe 2 in a state where they are separated along the first direction D0.

  Thus, the measurement error of the strain of the boiler pipe 2 is obtained by being placed in the boiler pipe 2 with the contact portion 115 and the abutted portion 126 being separated along the first direction D0. It can be reduced.

  The details will be described below. The boiler piping 2 of the thermal power plant becomes hot and thermally expands when the power generation device is operated. Therefore, when the first holding member 12A and the second holding member 12B are fixed to the boiler pipe 2 with the boiler pipe 2 at normal temperature, the contact between the abutted portion 126 and the abutted portion 115 and the abutted portion 126A When the power generation apparatus is operated and the temperature of the boiler pipe 2 is raised with no gap provided between the contact portion 115A and the contact portion 115A, the contact portion 115 of the fracture detection main member 11 is a cover of the holding member 12 It may have already been pulled by the abutment 126. Thus, it is conceivable that tensile stress is already applied to the breakage detection main member 11 in a state before strain detection is performed. Therefore, originally, for example, the break detection main member 11 may be broken when the boiler piping 2 is extended by, for example, 10 mm, but the break detection main member 11 may be broken at an elongation of 5 mm. In this case, since a measurement error occurs, it becomes difficult to detect an accurate amount of distortion. As described above, the measurement error of the strain measurement can be reduced by being placed in the boiler pipe 2 in a state in which the contact portion 115 and the contact portion 126 are separated along the first direction D0. it can.

  In the state where the boiler pipe 2 is installed, the abutting portion 115 and the abutted portion 126 are separated along the first direction D0. For this reason, even in a state where the power generation apparatus is operated and the boiler pipe 2 is in a high temperature, the contact portion 115 and the abutted portion 126 are in the first direction D0 until a predetermined distortion occurs due to the creep phenomenon of the boiler pipe 2 Are separated along the Then, when a predetermined distortion occurs due to the creep phenomenon of the boiler pipe 2 and the abutting portion 115 and the abutted portion 126 abut, the distortion detection device 1 can properly detect the distortion.

  Further, the distance between the first holding member 12A and the second holding member 12B is determined by setting the first holding member 12A and the first holding member 12A in a state where the first holding member 12A and the second holding member 12B are installed in the boiler pipe 2 in a state where the contact portion 115 is separated from the abutted portion 126. When the distance between the second holding member 12B and the second holding member 12B is greater than the distance L1, the contact portion 115 and the contact portion 126 contact each other.

  When the separation distance between the contact portion 115 and the abutted portion 126 in the state where the strain detection device 1 is installed in the boiler pipe 2 is too large, even if the boiler pipe 2 is creep-deformed, the contact portion 115 abuts The case where it does not abut on 126 is considered. Therefore, by placing the strain detection device 1 on the boiler pipe 2 in a state where the separation distance between the contact portion 115 and the contact portion 126 is an appropriate distance, the contact portion 115 contacts the contact portion 126. At the same time, appropriate distortion detection can be performed.

  The breakage detection main member 11 includes a cylindrical portion having a central axis AX along the longitudinal direction. Therefore, since the fracture detection main member 11 has a shape that is symmetrical in the radial direction about the central axis AX, the stress applied to the fracture detection main member 11 becomes even in the radial direction. Here, when the stress applied to the fracture detection main member 11 is uneven in the radial direction, it is conceivable that the fracture detection main member 11 fractures at a value smaller than the original elongation amount. Therefore, in the present embodiment, accurate distortion detection can be performed.

  The cylindrical portion of the breakage detection main member 11 extends in the longitudinal direction from the large diameter portions 110A and 110B which are the end portions held by the holding member 12 and the large diameter portions 110A and 110B, and the diameter is larger than that of the large diameter portions 110A and 110B. And a small diameter portion 111. As described above, the large diameter portions 110A and 110B can be held by the holding member 12, and the necessary function can be provided by the breakage detection main member 11 having a simple structure in which the small diameter portion 111 is broken.

  The abutting portion 115 has a tapered portion 113 whose outer diameter increases as going in the first direction D0 (elongation direction), and the abutted portion 126 has a large inner diameter as going in the first direction D0 (elongation direction) And a tapered portion 125.

  As described above, since the contact portion 115 and the contact portion 126 both have the tapered portions 113 and 125, the breakage detection main member 11 receives a load in a wide area. Therefore, since the breakage detection main member 11 can receive the load evenly over the entire contact portion 115, it is possible to perform accurate strain detection as compared with the case where the load is received locally.

  The breakage detection main member 11 has a small diameter portion 114 (breakable portion). Therefore, as compared with the case where the small diameter portion 114 is not provided, the breakage detection main member 11 can be more reliably broken with a small tensile stress.

  The breakage detection main member 11 has a conductive portion 131 which is covered with the outer peripheral surface of the small diameter portion 114 (easy to break portion) to be conductive and is breakable together with the small diameter portion 114 (easy to break portion).

  Therefore, since breakage of the breakage detection main member 11 is detected by breakage of the conductive portion 131 together with the small diameter portion 114 (breakable portion), breakage of the breakage detection main member 11 is achieved at a low cost and with a simple structure. It is detected.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 7 is a cross-sectional view enlarging a part of the strain detection device 1A according to the second embodiment.

  As shown in FIG. 7, in the strain detection device 1A according to the second embodiment, the breakage detection main member 11A has a large diameter portion 110C and a small diameter portion 111A. The end face on the longitudinal center side of the large diameter portion 110C is formed as a flat portion 113A. The flat portion 113A is a flat surface extending in the radial direction orthogonal to the central axis AX. The flat portion 113A is the contact portion 115A.

  The third holding member 12C has a flat portion 125A disposed to face the flat portion 113A of the breakage detection main member 11A and separated therefrom. The flat portion 125A is a flat surface extending in the radial direction orthogonal to the central axis AX. The flat portion 125A is the abutted portion 126A. A gap G1 is provided between the flat portion 113A (contact portion 115A) and the flat portion 125A (contacted portion 126A) along the longitudinal direction.

  As described above, according to the present embodiment, the abutting portion 115A and the abutted portion 126A extend in the radial direction of the breakage detection main member 11A at right angles (crosses) to the central axis AX.

  Therefore, it becomes easy to accurately measure the distance along the longitudinal direction between the contact portion 115A and the contact portion 126A.

Third Embodiment
Next, a third embodiment of the present invention will be described. FIG. 8 is a schematic view of the distortion detection device 1B according to the third embodiment as viewed from the upper side.

  As shown in FIG. 8, a distortion detection device 1B according to the third embodiment is a unit in which a plurality of distortion detection devices 1 described in the first embodiment are arranged in parallel. Specifically, the parallel direction of the strain detection device 1 is a direction orthogonal (crossed) to the longitudinal direction (first direction D0) and along the surface 2 a of the boiler pipe 2. In the present embodiment, the three strain detection devices 1 are disposed in parallel, and the first holding member 12A and the second holding member 12B are fixed to the surface 2a of the boiler pipe 2, respectively.

  As described above, the strain detection device 1B according to the present embodiment makes the strain detection device 1 described in the first embodiment orthogonal (intersect) to the longitudinal direction (first direction D0), and the surface 2a of the boiler pipe 2 Are arranged side by side in the parallel direction along the.

  Therefore, since an average value obtained by averaging the detection values of the plurality of strain detection devices 1 can be obtained, it is possible to obtain a more accurate detection value than the detection value of one strain detection device 1.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. FIG. 9 is a schematic view of a distortion detection device 1C according to the fourth embodiment as viewed from the side.

  As shown in FIG. 9, a strain detection apparatus 1C according to the fourth embodiment is a unit in which a plurality of strain detection apparatuses 1 described in the first embodiment are stacked. Specifically, the stacking direction of the strain detection device 1 is a direction orthogonal (crossed) to the longitudinal direction (first direction D0) and a direction away from the surface 2 a of the boiler pipe 2.

  In the present embodiment, the three strain detection devices 1 are vertically stacked, and the lowermost holding member 12 is fixed to the surface 2 a of the boiler pipe 2. That is, the holding member 12 of the strain detection device 1 on the lowest side (lowermost side) is fixed to the surface 2 a of the boiler pipe 2. The holding member 12 of the strain detection device 1 which is the second from the bottom (the center side in the vertical direction) is fixed on the holding member 12 of the strain detection device 1 on the lowermost side. The holding member 12 of the third (uppermost) strain detection device 1 from the lower side is fixed on the holding member 12 of the second (lowermost, middle side) strain detection device 1 from the lower side.

  As described above, a plurality of strain detection devices 1 described in the first embodiment are stacked in the height direction orthogonal to (crossed with) the longitudinal direction (first direction D0) and away from the surface 2a of the boiler pipe 2 As a result, the distortion detection device 1C according to the present embodiment is configured.

  Therefore, for example, the amount of strain can be detected more accurately by changing the separation distance between the contact portion 115 and the contact portion 126 in the longitudinal direction in order from the lower device to the upper device. For example, the separation distance of the first device from the bottom is set to 10 mm, the separation distance of the second device from the bottom to 20 mm, and the separation distance of the third device from the bottom to 30 mm. If the material is made of ceramic or the like and set so as to break with almost no elongation, the strain amount is between 20 mm and 30 mm when the break detection main member 11 of the second apparatus from the bottom breaks. Can be seen.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described. FIG. 10 is a schematic view showing a cross section of a boiler pipe 2 provided with a strain detection device 1D and a strain detection device 1D according to a fifth embodiment.

  In the first embodiment shown in FIG. 1, the first holding member 12 </ b> A and the second holding member 12 </ b> B are arranged straddling the welding portion 23. However, in the strain detection device 1D according to the fifth embodiment, the holding member 12D on the right side of FIG. 10 is fixed on the welding portion 23 (specifically, on the weld metal 24), and the holding member 12D on the left side is It may be fixed on the surface 2 a of the pipe 2. The strain detection device 1D includes a breakage detection main member 11D.

  As described above, according to the present embodiment, the strain detection device 1D can be installed even in a place where it is difficult to arrange across the weld portion 23.

Sixth Embodiment
Next, a sixth embodiment of the present invention will be described. FIG. 11 is a perspective view of a breakage detection main member according to a sixth embodiment. FIG. 12 is a schematic view of the distortion detection device according to the sixth embodiment as viewed from the upper side.

  As shown in FIG. 11, the fracture detection main member 11E according to the sixth embodiment has the shape of a flat plate formed to have substantially the same thickness throughout. The breakage detection main member 11E has a wide portion 110E (first end), a narrow portion 111E, and a wide portion 110F (second end).

  The width of the wide portion 110E in the direction orthogonal to the central axis AX is larger than the width of the narrow portion 111E. The width of the wide portion 110F in the direction orthogonal to the central axis AX is larger than the width of the narrow portion 111E. The width of the wide portion 110E is substantially the same as the width of the wide portion 110F.

  The end face on the central side in the longitudinal direction of the wide portion 110E is formed on a curved surface 113E. The curved surface 113E is formed in a shape curved in an arc shape in plan view. The curved surface 113E is an abutting portion 115E. The end face on the longitudinal center side of the wide portion 110F is formed on a curved surface 113F. The curved surface 113F is formed in a shape curved in an arc shape in plan view. The curved surface 113F is the contact portion 115E. As a material of the breakage detection main member 11E, a ceramic that is easily broken can be applied.

  As shown in FIG. 12, the strain detection device 1E includes a breakage detection main member 11E, a first holding member 12E and a second holding member 12F, and a breakage detection device 13.

  The wide portions 110E and 110F are end portions of the breakage detection main member 11E in the extension direction (first direction D0). Specifically, the first end portion disposed on the right side (the first extension direction D1 side) of FIG. 12 is the wide portion 110E. The second end portion disposed on the left side (second extension direction D2 side) of FIG. 12 is the wide portion 110F. The wide portion 110E (first end) is held by the first holding member 12E. The wide portion 110F (second end) is held by the second holding member 12F.

  An abutted portion 126E is provided on the first holding member 12E. The abutted portion 126E is disposed to face the curved surface 113E (abutment portion 115E) of the breakage detection main member 11E. The abutted portion 126E has a shape of a circular arc convex toward the curved surface 113E. The curved surface 113E (the contact portion 115E) has an arc shape which is recessed in a direction away from the abutted portion 126E. That is, the abutted portion 126E is curved along the curved surface 113E.

  The second holding member 12F is provided with an abutted portion 126E. The abutted portion 126E is disposed to face the curved surface 113F (abutment portion 115E) of the breakage detection main member 11E. The abutted portion 126E has a shape of a circular arc convex toward the curved surface 113F. The curved surface 113F (the contact portion 115E) has an arc shape which is recessed in a direction away from the abutted portion 126E. That is, the abutted portion 126E is curved along the curved surface 113F. The curved surfaces 113E and 113F (the abutment portion 115E) and the abutted portion 126E are separated along the first direction D0.

  As described above, the fracture detection main member 11E according to the present embodiment has a flat plate shape formed to have substantially the same thickness throughout. The abutting portion 115E and the abutted portion 126E are installed in the boiler pipe 2 in a state where they are separated along the first direction D0.

  As described above, also in the breakage detection main member 11E having the shape of a flat plate formed to have substantially the same thickness over the whole, the abutting portion 115E and the abutted portion 126E are separated along the first direction D0. By setting the boiler pipe 2 in a set state, the measurement error of the strain of the boiler pipe 2 can be reduced.

  The specific configuration of the strain detection device in the embodiment is merely an example, and the present invention is not limited to this and can be appropriately changed.

  For example, in the first embodiment, only in the first holding member 12A, the abutting portion 115 is installed in the boiler pipe 2 in a state of being separated from the abutted portion 126. However, in both the first holding member 12 </ b> A and the second holding member 12 </ b> B, the abutting portion 115 may be installed on the boiler pipe 2 in a state of being separated from the abutted portion 126.

  Moreover, although the distortion detection apparatus 1B which concerns on 3rd Embodiment paralleled three distortion detection apparatuses 1, two may be sufficient and four or more may be sufficient. Furthermore, in the strain detection device 1C according to the fourth embodiment, the three strain detection devices 1 are stacked in the vertical direction, but may be two, or four or more.

1, 1A, 1B, 1C, 1D, 1E Strain detection device 2 Boiler piping (detected body)
11, 11A, 11D, 11E Fracture Detection Main Member 12A First Holding Member 12B Second Holding Member 21 First Base Material (First Part)
22 Second base material (second part)
115, 115A, 115E contact portion 126, 126A, 126E abutted portion 110A large diameter portion (first end, cylindrical portion)
110B large diameter part (second end, cylindrical part)
110E wide part (first end)
110F wide part (second end)
111, 111A Small diameter part (cylindrical part)
113, 125 Tapered part 114 Small diameter part (Easy to break part)
131 Conductor (break detection unit)
AX central axis D0 first direction

Claims (9)

A breakage detection main member having a breakage easy portion that can be broken when a tensile stress is applied in a first direction;
A breakage detection unit provided at a portion of the breakage detection main member across the easy breakage portion;
A first holding member fixed to the first portion of the detection subject and holding the first end of the breakage detection main member;
A second holding member fixed to the second part of the detection subject and holding the second end of the breakage detection main member;
Equipped with
The first end and the second end each have an abutment.
Each of the first holding member and the second holding member has an abutted portion facing the abutting portion,
In at least one of the first holding member and the second holding member, the contact portion is disposed on the detection target in a state of being separated from the abutted portion,
Strain detection device. When the distance between the first holding member and the second holding member is set on the detection target in a state in which the contact portion is separated from the contact portion, the first holding member and the first When the distance between the second holding member and the second holding member is greater than the second holding member, the contact portion and the contact portion contact
The distortion detection device according to claim 1. The breakage detection main member and the breakage detection unit are disposed in a plurality in parallel directions crossing the first direction and along the surface of the detection target.
The distortion detection apparatus according to claim 1. The first holding member, the second holding member, the breakage detection main member, and the breakage detection portion are disposed in a plurality in a height direction crossing the first direction and away from the surface of the detection target.
The distortion detection apparatus according to claim 1. The fracture detection main member includes a cylindrical portion having a central axis along the first direction.
The distortion detection apparatus according to any one of claims 1 to 4. The cylindrical portion of the breakage detection main member is larger than the large diameter portion which is the first end and the second end held by the first holding member and the second holding member, and the large diameter portion Having a small diameter portion with a small diameter,
The distortion detection device according to claim 5. The contact portion has a tapered portion whose outer diameter increases in the first direction,
The abutted portion has a tapered portion whose inner diameter increases in the first direction.
The distortion detection apparatus according to claim 5. The contact portion and the contact portion extend in the radial direction of the breakage detection main member orthogonal to the central axis.
The distortion detection apparatus according to claim 5. The strain detection device according to any one of claims 1 to 8, wherein the breakage detection unit has a conductive portion which is covered with an outer peripheral surface of the breakage detection main member and which can conduct electricity and which can be broken together with the easy breakage portion. .

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