Mechanism for detecting change in bellows-type expansion joint

Abstract

To provide a change amount detection mechanism which can exactly measure an axial displacement amount, an axial orthogonal displacement amount and an axial bend displacement amount of a bellows-type telescopic pipe joint.SOLUTION: A change amount detection mechanism of a bellows-type telescopic pipe joint comprises a bellows-type telescopic pipe joint, and measurement means for measuring a displacement amount of the telescopic pipe joint. The telescopic pipe joint comprises a one-side end pipe which is fixed and connected to a first pipe conduit, the other side end pipe which is fixed and connected to a second pipe conduit, a center pipe located between the one-side end pipe and the other side end pipe, a first bellows pipe for telescopically connecting the one-side end pipe and the center pipe, and a second bellows pipe for telescopically connecting the other side end pipe and the center pipe. The measurement means comprises a first inclination sensor for measuring an inclination angle of the one-side end pipe, a second inclination sensor for measuring an inclination angle of the other side end pipe, a third inclination sensor for measuring an inclination angle of the center pipe, a first distance sensor for measuring an elongation amount of the first bellows pipe, and a second distance sensor for measuring an elongation amount of the second bellows pipe.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to an expansion joint installed for the purpose of protecting pipelines from earthquakes and subsidence, and more particularly to a detection mechanism for detecting the amount of change in the expansion joint. [Background technology]

[0002] Typical expansion joints include sleeve-type expansion joints, in which an inner tube and an outer tube are fitted together so as to be axially slidable, and bellows-type expansion joints, which have a bellows section formed from a pipe made of stainless steel or the like in a corrugated shape.

[0003] Sleeve-type expansion joints are disclosed, for example, in Japanese Patent Publication No. 6639423 (Patent Document 1). The expansion joint disclosed in Patent Document 1 comprises one end pipe fixed to one conduit located on one side, another end pipe fixed to the other conduit located on the other side, and a sleeve fitted to the one end pipe and the other end pipe so as to be relatively movable in the axial direction of the pipe.

[0004] Patent Document 1 also discloses a behavioral exploration device for exploring the behavior of an expansion joint of the above structure. The behavioral exploration device comprises a first sensor that measures the change in distance between a sleeve and one end pipe and transmits the measured data, and a second sensor that measures the change in distance between the sleeve and the other end pipe and transmits the measured data, and calculates the displacement position of the first and second pipes relative to the expansion joint from the measurement data from the first sensor and the measurement data from the second sensor.

[0005] Sleeve-type expansion joints effectively absorb displacement in the axial direction (hereinafter referred to as "axial direction") and rotation around the axis, i.e., displacement in the axial rotation direction. However, their absorption performance is not very good for displacement perpendicular to the axis or in the axial bending direction. Therefore, when large displacements are applied to the piping in the direction perpendicular to the axis or in the axial bending direction due to the effects of earthquakes or other factors, there is a risk of pipe detachment and, consequently, fluid leakage in the case of sleeve-type expansion joints.

[0006] A bellows-type expansion joint is disclosed, for example, in Japanese Patent Publication No. 6960128 (Patent Document 2). The bellows-type expansion joint is equipped with a bellows tube formed from a pipe made of stainless steel or the like in a corrugated shape, and plays a role in absorbing displacements that occur in the piping by deforming while maintaining airtightness and liquid tightness.

[0007] Figure 1 shows the axial displacement, perpendicular displacement, and axial bending displacement of a bellows tube. A bellows-type expansion joint equipped with a bellows tube can absorb all three types of displacement in combination: axial displacement, perpendicular displacement, and axial bending displacement. However, its absorption performance for axial rotational displacement is not very good. When a large displacement is applied to the piping due to an earthquake or other effect, a sleeve-type expansion joint may detach, but a bellows-type expansion joint will undergo abnormal deformation but will not detach and will maintain the flow of fluid.

[0008] Pipelines exist not only on the surface but also underground. Bellows-type expansion joints are sometimes buried underground. In such cases, even if a bellows-type expansion joint experiences significant displacement due to an earthquake or differential settlement, the deformation of the joint cannot be visually inspected from the surface. Therefore, it may be difficult to determine whether replacement is necessary, and unnecessary excavation work may be carried out to check the condition even if there is little displacement and replacement is not needed.

[0009] Furthermore, if an unexpectedly excessive displacement occurs in a bellows-type expansion joint, the joint may break and internal fluid may leak. However, in such cases, it is difficult to assess the situation without excavation work.

[0010] Patent Document 2 also discloses a pipeline information acquisition device for acquiring information related to bellows-type expansion joints. The pipeline information acquisition device comprises a deformable bellows section provided in the pipeline, a power generation section provided in the bellows section that generates electricity in accordance with the deformation movement of the bellows section, an information acquisition section that acquires pipeline information, which is information about the pipeline, a transmission section that wirelessly transmits the pipeline information, and an external receiving means that receives signals transmitted from the transmission section.

[0011] By utilizing the remote monitoring system equipped with the above pipeline information acquisition device or the like, it is possible to easily monitor pipelines in an environment where it is difficult to confirm the state from a remote location.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0013] The remote monitoring system as disclosed in Patent Document 2 has the following problems.

[0014] The first problem is as follows. The bellows type expansion joint has displacement performance in "axial displacement", "displacement perpendicular to the axis", and "axial bending displacement". When an earthquake or the like occurs, not only axial displacement but also displacement perpendicular to the axis and axial bending displacement may act on the bellows part in a complex manner. In that case, even if the expansion amount of the bellows part is measured, displacement components due to displacement perpendicular to the axis and axial bending displacement are added to the expansion amount, so an accurate measurement result cannot be grasped.

[0015] The second problem is as follows. There are cases where angular displacement occurs between the one-side pipeline and the other-side pipeline connected to both ends of the bellows type expansion joint. However, in the device as disclosed in Patent Document 2, the angular displacement as a bellows type expansion joint cannot be accurately measured.

[0016] The third problem is as follows. Even in the case of pipelines buried underground, the temperature near the sensor changes due to the seasons and the difference in the laying location, so the measurement result of the sensor also includes the influence of temperature change.

[0017] The fourth challenge is as follows: While a large leak from a bellows-type expansion joint would be easy to detect, a small leak might go undetected for a long time, potentially leading to a disruption of essential services in the worst-case scenario. Early detection of internal fluid leaks is therefore necessary.

[0018] The object of the present invention is to provide a mechanism for detecting changes in a bellows-type expansion joint that can accurately measure the axial displacement, the displacement perpendicular to the axis, and the displacement in the axial bending direction of the bellows-type expansion joint.

[0019] Another objective of the present invention is to enable the acquisition of measurement data that also takes into account the effects of temperature changes near the sensor.

[0020] Another objective of the present invention is to enable the detection of unexpected displacement or fluid leakage due to aging, and to allow for the prompt repair or replacement of bellows-type expansion joints.

[0021] Another object of the present invention is to enable remote monitoring of the axial displacement, perpendicular displacement, and axial bending displacement of a bellows-type expansion joint from a location away from the bellows-type expansion joint. [Means for solving the problem]

[0022] The bellows-type expansion joint change detection mechanism according to the present invention comprises a bellows-type expansion joint that expandably connects a first pipe located on one side and a second pipe located on the other side, and a measuring means for measuring the displacement of the bellows-type expansion joint.

[0023] A bellows-type expansion joint comprises one end pipe fixedly connected to a first conduit, the other end pipe fixedly connected to a second conduit, a central pipe located between the one end pipe and the other end pipe, a first bellows pipe that expandably connects the one end pipe and the central pipe, and a second bellows pipe that expandably connects the other end pipe and the central pipe.

[0024] The measuring means includes a first tilt sensor for measuring the tilt angle of one end pipe, a second tilt sensor for measuring the tilt angle of the other end pipe, a third tilt sensor for measuring the tilt angle of the central pipe, a first distance sensor for measuring the expansion and contraction amount of the first bellows pipe, and a second distance sensor for measuring the expansion and contraction amount of the second bellows pipe.

[0025] Preferably, the change detection mechanism for the bellows-type expansion joint further includes a displacement calculation means that calculates the axial displacement, the displacement perpendicular to the axis, and the axial bending displacement in the bellows-type expansion joint based on the values ​​measured by the measuring means.

[0026] Preferably, the measuring means further comprises a leak sensor attached to the central tube for detecting leakage of internal fluid.

[0027] In one embodiment of the present invention, one end pipe comprises a one end pipe flange extending radially outward and an outer cylinder extending axially from the one end pipe flange and surrounding the first bellows pipe. The other end pipe comprises a other end pipe flange extending radially outward and an outer cylinder extending axially from the other end pipe flange and surrounding the second bellows pipe. The first distance sensor measures the change in axial distance between the outer cylinder and the first bellows pipe, and the second distance sensor measures the change in axial distance between the outer cylinder and the second bellows pipe.

[0028] Preferably, the measuring means further includes a temperature sensor for measuring the temperature near the bellows-type expansion joint, and the displacement calculation means includes a temperature correction means for correcting the values ​​measured by each sensor to room temperature values ​​based on the temperature measured by the temperature sensor.

[0029] Preferably, the displacement calculation means is located away from the bellows-type expansion joint, and the measurement means transmits the measured data wirelessly to the displacement calculation means. [Effects of the Invention]

[0030] According to the present invention, since the measuring means includes a first tilt sensor, a second tilt sensor, a third tilt sensor, a first distance sensor, and a second distance sensor, the axial displacement, perpendicular displacement, and axial bending displacement of the bellows-type expansion joint can be accurately measured. [Brief explanation of the drawing]

[0031] [Figure 1] This figure shows the axial displacement, displacement perpendicular to the axis, and displacement in the axial bending direction of the bellows tube. [Figure 2] This diagram illustrates the overall configuration of the change amount detection mechanism for a bellows-type expansion joint according to the present invention. [Figure 3] This is a diagram illustrating the structure of a bellows-type expansion joint according to one embodiment of the present invention. [Figure 4] This diagram shows symbols for the inclination angles of each part of an expansion joint and symbols for the length of the central pipe. [Figure 5] This diagram shows the axial displacement of a single bellows tube. [Figure 6] This diagram illustrates the calculation of the axial displacement of the entire expansion joint. [Figure 7] This diagram illustrates the calculation of the total displacement of an expansion joint perpendicular to its axis. [Modes for carrying out the invention]

[0032] [Overall structure]

[0033] In a bellows-type expansion joint, axial displacement, displacement perpendicular to the axis, and displacement in the axial bending direction act in combination. However, according to the change amount detection mechanism of the present invention, the change amount generated in the bellows-type expansion joint can be accurately decomposed into the displacement components in the axial, perpendicular to the axis, and axial bending directions.

[0034] Referring to Figure 2, the overall configuration of the bellows-type expansion joint change detection mechanism according to the present invention will be described. The bellows-type expansion joint change detection mechanism comprises a bellows-type expansion joint 10 that expandably connects a first conduit 1 located on one side and a second conduit 2 located on the other side, and a measuring means 30 for measuring the displacement of the bellows-type expansion joint 10. In a preferred embodiment, the change detection mechanism further includes a displacement calculation means 40 that calculates the axial displacement, the displacement perpendicular to the axis, and the axial bending displacement in the bellows-type expansion joint based on the values ​​measured by the measuring means 30.

[0035] When the bellows-type expansion joint 10 is buried underground, preferably the displacement calculation means 40 is located away from the bellows-type expansion joint 10, and the measurement means 30 wirelessly transmits the measured data to the displacement calculation means 40.

[0036] [Configuration of a bellows-type expansion joint]

[0037] Referring to Figure 3, the structure of a bellows-type expansion joint 10 according to one embodiment of the present invention will be described. The bellows-type expansion joint 10 comprises one end pipe 11 fixedly connected to a first conduit 1 at the end flange 11a, the other end pipe 12 fixedly connected to a second conduit 2 at the end flange 12a, a central pipe 13 located between the one end pipe 11 and the other end pipe 12, a first bellows pipe 14 that expandably connects the one end pipe 11 and the central pipe 13, and a second bellows pipe 15 that expandably connects the other end pipe 12 and the central pipe 13.

[0038] The one-end tube 11 comprises a one-end tube flange 11b extending radially outward and an one-end tube outer cylinder 11c extending axially from an intermediate position on the one-end tube flange 11b. One end of the first bellows tube 14 is fixed to the one-end tube flange 11b, and the other end is fixed to one end flange 13a of the central tube 13.

[0039] The other end pipe 12 comprises a flange 12b extending radially outward and an outer cylinder 12c extending axially from an intermediate position on the flange 12b. One end of the second bellows pipe 15 is fixed to the other end flange 13b of the central pipe 13, and the other end is fixed to the flange 12b.

[0040] The outer casing 11c at one end surrounds the first bellows tube 14 to prevent soil and other debris from entering the bellows-shaped portion of the first bellows tube 14. Similarly, the outer casing 12c at the other end surrounds the second bellows tube 15 to prevent soil and other debris from entering the bellows-shaped portion of the second bellows tube 15.

[0041] When the first bellows pipe 14 and the second bellows pipe 15 expand or contract or bend due to an earthquake or subsidence, the central pipe 13 is displaced axially, perpendicular to the axis, or in an inclined direction relative to the one end pipe 11 and the other end pipe 12.

[0042] [Configuration of the measurement means]

[0043] Referring to Figure 3, the configuration of the measuring means 30 will be described. The measuring means 30 includes, for example, a first tilt sensor 31 attached to the outer surface of the one end pipe 11 to measure the tilt angle of the one end pipe 11, a second tilt sensor 32 attached to the outer surface of the other end pipe 12 to measure the tilt angle of the other end pipe 12, a third tilt sensor 33 attached to the outer surface of the central pipe 13 to measure the tilt angle of the central pipe 13, a first distance sensor 34 for measuring the expansion and contraction amount of the first bellows pipe 14, and a second distance sensor 35 for measuring the expansion and contraction amount of the second bellows pipe 15.

[0044] In the illustrated embodiment, the first distance sensor 34 measures the change in axial distance between the outer cylinder 11c of one end pipe and the first bellows pipe 14, and the second distance sensor 35 measures the change in axial distance between the outer cylinder 12c of the other end pipe and the second bellows pipe 15. Specifically, the first distance sensor 34 measures the distance between the inward flange of the outer cylinder 11c of one end pipe and the flange 13a of one end of the central pipe 13, and the second distance sensor 35 measures the distance between the inward flange of the outer cylinder 12c of the other end pipe and the flange 13b of the other end of the central pipe 13.

[0045] The distance sensors 34 and 35 shown in Figure 3 are illustrative examples, and other structures and arrangements may be used. In short, the first and second distance sensors can have any structure and arrangement as long as they can measure the expansion and contraction of the first and second bellows tubes.

[0046] Preferably, the measuring means 30 further includes a leak sensor 36 attached to the outer surface of the central pipe 13 to detect leakage of internal fluid, and a temperature sensor 37 for measuring the temperature near the bellows-type expansion joint 10. The leak sensor 36 detects vibrations of the central pipe 13 and sounds of fluid leakage. In the illustrated embodiment, the temperature sensor 37 is positioned near the tilt sensors 31, 32, 33 and distance sensors 34, 35 to measure the temperature of each sensor. In another embodiment, only one temperature sensor may be positioned near the bellows-type expansion joint.

[0047] [Configuration and operation of the displacement calculation means]

[0048] The displacement calculation means 40 calculates the axial displacement, the displacement perpendicular to the axis, and the displacement in the axial bending direction of the bellows-type expansion joint 10 based on the values ​​measured by the measurement means 30. In the embodiment of the present invention, the displacement calculation means 40 further includes a temperature correction means 41 that corrects the values ​​measured by the tilt sensors 31, 32, 33 and the distance sensors 34, 35 to values ​​at room temperature based on the temperature measured by the temperature sensor.

[0049] The first distance sensor 34 and the second distance sensor 35 measure the axial displacement of the first bellows pipe 14 and the second bellows pipe 15, respectively. At this time, the axial displacement of the bellows-type expansion joint 10 is corrected based on the measurement results of the inclination angle measured by the first inclination sensor 31, the second inclination sensor 32, and the third inclination sensor 33.

[0050] The amount of displacement of the expansion joint 10 perpendicular to its axis is calculated based on the measurement results of the inclination angles by the first, second, and third inclination sensors 31, 32, and 33 attached to one end pipe 11, the other end pipe 12, and the central pipe 13, and the measurement results of the expansion and contraction amounts by the first and second distance sensors 34 and 35. At that time, since there is a possibility that the first conduit 1 or the second conduit 2 to which the expansion joint 10 is connected is undergoing angular displacement, the inclination angle (amount of displacement in the axial bending direction) of the expansion joint 10 is corrected based on the measurement results of the inclination angles of the one end pipe 11, the other end pipe 12, and the central pipe 13.

[0051] Based on the measurement results of the temperature sensor 37 positioned near the tilt sensors 31, 32, 33 and distance sensors 34, 35, the temperature correction means 41 corrects the axial displacement, perpendicular displacement, and axial bending displacement of the expansion joint 10.

[0052] Unexpected displacement may occur in the bellows-type expansion joint 10, causing fluid leakage. Furthermore, fluid leakage may occur independently of displacement due to the aging of the expansion joint's components. The leak sensor 36 detects vibrations in the central pipe 13 and the sound of fluid leakage, ensuring that even small amounts of fluid leakage are detected without being overlooked.

[0053] [Displacement of a bellows tube alone]

[0054] The individual displacements of bellows tubes 14 and 15 are of the following two types:

[0055] - Axial displacement

[0056] - Axial bending direction displacement

[0057] In an expansion joint with multiple bellows tubes, axial bending displacement occurs before axial displacement occurs in individual bellows tubes, and the expansion joint as a whole, including the central tube 13, absorbs the axial displacement. Therefore, it is assumed that there is no axial displacement in individual bellows tubes.

[0058] [Overall displacement of the expansion joint]

[0059] The overall displacement of the expansion joint 10 can be of the following three types:

[0060] - Axial displacement

[0061] - Displacement perpendicular to the axis

[0062] - Axial bending direction displacement

[0063] [Regulations regarding the positive and negative signs of the inclination angle]

[0064] Figure 4 is a diagram showing the symbols for the inclination angles of each part of the expansion joint 10 and the symbol for the length of the central pipe 13. The symbols for the inclination angles shown in Figure 4 are as follows:

[0065] θ L : Inclination angle of one end pipe 11

[0066] θ R : Inclination angle of the other end pipe 12

[0067] θ C : Inclination angle of the central tube 13

[0068] θ1: Axial bending displacement angle of the first bellows tube 14

[0069] θ2: Axial bending displacement angle of the second bellows tube 15

[0070] θ: Overall axial bending displacement angle of the expansion joint 10

[0071] L: Axial length of central tube 13

[0072] Each of the tilt sensors 31, 32, and 33 measures the tilt angle from the horizontal state. For θ1 and θ2, when the bellows part on the top side (upper side in the vertical direction) extends, it is considered negative, and when it contracts, it is considered positive.

[0073] [Calculation of the amount of displacement in the axial bending direction of a single bellows]

[0074] The amount of axial bending displacement (displacement angle) θ1 of the first bellows tube 14 is calculated by the following formula.

[0075] θ1 = θ C -θ L

[0076] The amount of axial bending displacement (displacement angle) θ2 of the second bellows tube 15 is calculated by the following formula.

[0077] θ2 = θ R -θ C

[0078] [Calculation of the amount of axial displacement of a single bellows tube]

[0079] Figure 5 is a diagram for showing the amount of axial displacement of a single bellows tube.

[0080] The amount of axial displacement (expansion and contraction amount) of the single first bellows tube 14 and the second bellows tube 15 is the amount of change in the distance measured by the distance sensors 34, 35. In Figure 5, the amount of axial displacement of the first bellows tube 14 is shown as ΔX L Although not shown, the amount of axial displacement of the second bellows tube 15 is taken as ΔX R

[0081] [Calculation of the amount of axial bending displacement of the entire telescopic pipe joint]

[0082] The amount of axial bending displacement (displacement angle) θ of the entire telescopic pipe joint 10 is calculated by the following formula.

[0083] θ = θ R -θ L ​

[0084] [Calculation of the axial displacement of the entire expansion joint]

[0085] Figure 6 is a diagram illustrating the calculation of the axial displacement of the entire expansion joint.

[0086] The total axial displacement ΔX' of the expansion joint 10 is the horizontal component excluding the axial bending displacement of each bellows tube 14, 15. The concept of the axial displacement of the first bellows tube 14 will be explained with reference to Figure 6.

[0087] The horizontal component ΔX' of the first bellows tube 14. L It is calculated using the following formula.

[0088] ΔX' L =ΔX L ×cosθ1

[0089] The horizontal component ΔX' of the second bellows tube 15. R It is calculated using the following formula.

[0090] ΔX' R =ΔX R ×cosθ²

[0091] The overall axial displacement ΔX' of the expansion joint 10 is the sum of the two displacements mentioned above.

[0092] ΔX'=ΔX' L +ΔX' R

[0093] [Calculation of the displacement of the entire expansion joint perpendicular to the axis]

[0094] Figure 7 is a diagram illustrating the calculation of the total displacement of the expansion joint 10 in the direction perpendicular to the axis.

[0095] Let B be the dimension of the bellows tube alone, and let ΔX be the measurement value from the distance sensor.

[0096] Displacement amount ΔY of the first bellows tube 14 in the direction perpendicular to the axis LIt is calculated using the following formula.

[0097] ΔY L ={( B L ( / 2) + ΔX L} × sinθ1

[0098] Displacement amount ΔY of the second bellows tube 15 in the direction perpendicular to the axis R It is calculated using the following formula.

[0099] ΔY R ={( B R ( / 2) + ΔX R} × sin(θ²-θ)

[0100] Displacement amount ΔY due to the tilt of the central pipe 13 C It is calculated using the following formula.

[0101] ΔY C =L×sinθ1

[0102] The overall displacement ΔY of the expansion joint 10 in the direction perpendicular to the axis is the sum of the three displacement amounts described above.

[0103] ΔY = ΔY C +ΔY L +ΔY R

[0104] [Temperature compensation for axial bending displacement of the first bellows tube]

[0105] The following is an illustrative example of a correction formula for the first bellows tube 14 when there is a difference between the actual temperature at the time of measurement and the design reference temperature (e.g., 20°C).

[0106] The assumed conditions are as follows:

[0107] Reference temperature (design temperature): 20℃

[0108] Temperature at time of measurement: 10℃

[0109] Temperature characteristics: ±0.02° / ℃

[0110] Let's consider the correction formula when using a tilt sensor under the above conditions.

[0111] Let's take the displacement θ1 in the axial bending direction of the first bellows tube 14 as an example. C =5°, θ L When = -2°, θ C If only the error occurs, it will be as follows:

[0112] With correction applied, the displacement angles will be as follows.

[0113] θ1 = θ C -θ L =7°

[0114] Without correction, the displacement angles will be as follows.

[0115] θ1=(θ C (+0.02×t)-θ L =5.2-(-2)=7.2°

[0116] Without temperature correction, measurement data will have an error of 0.2° compared to the actual measurement result.

[0117] [Scope of the Invention and Advantages of Preferred Embodiments]

[0118] Although embodiments of the present invention have been described above with reference to the drawings, the illustrated embodiments are illustrative and various modifications and variations can be made within the same scope as the present invention or within the equivalent scope.

[0119] According to the present invention, the displacement of a bellows-type expansion joint can be accurately detected. If a remote monitoring system is installed, as described in the preferred embodiment, the following advantages can be expected. a) It will be possible to plan the repair / replacement of expansion joints. b) The ability to detect leaks due to unexpected displacement or deterioration will enable prompt repair / replacement of expansion joints. c) Confirmation of displacement after an earthquake will enable the acquisition of data for seismic performance design of expansion joints. [Industrial applicability]

[0120] The present invention can be advantageously utilized as a mechanism that can accurately detect the amount of change in a bellows-type expansion joint. [Explanation of Symbols]

[0121] 1 First conduit, 2 Second conduit, 10 Bellows-type expansion joint, 11 One end pipe, 11a End flange, 11b One end pipe flange, 11c One end pipe outer cylinder, 12 Other end pipe, 12a End flange, 12b Other end pipe flange, 12c Other end pipe outer cylinder, 13 Central pipe, 14 First bellows pipe, 15 Second bellows pipe, 30 Measuring means, 31 First tilt sensor, 32 Second tilt sensor, 33 Third tilt sensor, 34 First distance sensor, 35 Second distance sensor, 36 Leak sensor, 37 Temperature sensor, 40 Displacement amount calculation means, 41 Temperature correction means.

Claims

1. A bellows-type expansion joint that expands and contracts to connect a first conduit located on one side and a second conduit located on the other side, The system includes a measuring means for measuring the displacement of the bellows-type expansion joint, The aforementioned bellows-type expansion joint is, A one-end pipe fixedly connected to the first conduit, The other end pipe is fixedly connected to the second conduit, A central pipe located between the aforementioned one end pipe and the aforementioned other end pipe, A first bellows tube connects the one end tube and the central tube in an expandable and retractable manner, The system includes a second bellows tube that connects the other end tube and the central tube in an extendable and retractable manner, The aforementioned measuring means is A first tilt sensor for measuring the tilt angle of the one end pipe, A second tilt sensor for measuring the tilt angle of the other end pipe, A third tilt sensor for measuring the tilt angle of the central pipe, A first distance sensor for measuring the expansion and contraction amount of the first bellows tube, The system includes a second distance sensor for measuring the amount of expansion and contraction of the second bellows tube, A mechanism for detecting changes in a bellows-type expansion joint, further comprising a displacement calculation means for calculating the axial displacement, the displacement perpendicular to the axis, and the displacement in the axial bending direction of the bellows-type expansion joint based on the values ​​measured by the aforementioned measuring means.

2. The bellows-type expansion joint change detection mechanism according to claim 1, further comprising a leak sensor attached to the central pipe for detecting leakage of internal fluid.

3. A bellows-type expansion joint that expands and contracts a first conduit located on one side and a second conduit located on the other side, The system includes a measuring means for measuring the displacement of the bellows-type expansion joint, The aforementioned bellows-type expansion joint is, A one-end pipe fixedly connected to the first conduit, The other end pipe is fixedly connected to the second conduit, A central pipe located between the aforementioned one end pipe and the aforementioned other end pipe, A first bellows tube connects the one end tube and the central tube in an expandable and retractable manner, The system includes a second bellows tube that connects the other end tube and the central tube in an extendable and retractable manner, The aforementioned measuring means is A first tilt sensor for measuring the tilt angle of the one end pipe, A second tilt sensor for measuring the tilt angle of the other end pipe, A third tilt sensor for measuring the tilt angle of the central pipe, A first distance sensor for measuring the expansion and contraction amount of the first bellows tube, The system includes a second distance sensor for measuring the amount of expansion and contraction of the second bellows tube, The aforementioned one-end tube comprises a one-end tube flange extending radially outward and an outer tube extending axially from the one-end tube flange and surrounding the first bellows tube. The other end pipe comprises a flange extending radially outward and an outer cylinder extending axially from the flange and surrounding the second bellows pipe. The first distance sensor measures the change in axial distance between the outer cylinder of the one end tube and the first bellows tube. The second distance sensor is a mechanism for detecting the amount of change in a bellows-type expansion joint, which measures the change in the axial distance between the outer cylinder of the other end pipe and the second bellows pipe.

4. The measurement means further includes a temperature sensor for measuring the temperature at a location near the bellows-type expansion joint. The displacement amount calculation means includes a temperature correction means for correcting the values ​​measured by each sensor to the values ​​at room temperature based on the temperature measured by the temperature sensor, the change amount detection mechanism for a bellows-type expansion joint according to claim 1.

5. The displacement calculation means is located away from the bellows-type expansion joint. The bellows-type expansion joint change detection mechanism according to claim 1, wherein the measurement means transmits the measured data wirelessly to the displacement calculation means.

Images