Expansion monitoring device and system

Abstract

The present invention discloses an expansion monitoring device and system. The expansion monitoring device includes a detection component and a plurality of variable components installed on the object to be detected. The detection component can obtain the displacement of the variable component; the detection component includes a main frame, a probe bracket installed on the main frame, and a displacement sensor installed on the probe bracket; the number of displacement sensors is at least three, and the displacement of the variable component in the X, Y, and Z directions is obtained respectively; the main frame includes at least three plates perpendicular to each other, each plate is equipped with at least one probe bracket, one end of the probe bracket is adjustably arranged on the plate, and the displacement sensor is installed at the other end of the probe bracket. The expansion monitoring device provided by the present invention uses the detection component and the variable group to obtain the displacement of each variable component in the X, Y, and Z directions to accurately obtain the expansion of the object to be detected in different directions, thereby improving the expansion monitoring accuracy.

Description

Technical Field

[0001] The present invention relates to the field of test strip detection equipment, and in particular to an expansion monitoring device. In addition, the present invention also relates to an expansion monitoring system comprising the above expansion monitoring device. Background Art

[0002] At present, boiler expansion monitoring still mainly records the data of mechanical expansion devices, and has not yet achieved true computer remote monitoring. There are several reasons for this:

[0003] First, the measurement problem has not been fundamentally solved. Currently, there are many multi-dimensional measurement solutions for boiler expansion, but most of them have the problems of simple principles, inconvenient installation and implementation, high costs, and difficulty in promotion.

[0004] Second, the boiler load of power plants was relatively stable in the past, so the number and amplitude of boiler expansion were small, and the urgency of monitoring and analyzing boiler expansion was not high. However, with the changes in the power grid structure, the boiler load of thermal power plants frequently changes from 30% to 100%, and even needs to be started and stopped frequently, so the frequency and amplitude of boiler expansion have increased significantly. In this case, there is an urgent need to continuously monitor and analyze the expansion of power plant boilers, understand the operating status of boilers, analyze the life and health of metals, and provide data support for optimizing the frequency of boiler maintenance and key inspection areas.

[0005] Third, there are a large number of expansion monitoring points in large boilers, which results in a large number of data collection points, a large number of cables and I / O cards required, and the cost cannot be effectively reduced.

[0006] In addition, in the prior art, the expansion of the boiler can be measured by ultrasonic displacement sensors, laser displacement sensors, or LVDT displacement sensors. When using an ordinary LVDT sensor, the LVDT pull rod needs to be fixed on the displacement variable component at one end, and the other end is fixed on a relatively fixed component through a universal joint. When the position of the moving component changes, the LVDT pull rod is extended and retracted, and at the same time, the pull rod drives the LVDT as a whole to move in position to ensure that the LVDT is always perpendicular to the displacement variable component. The function of the universal joint is to ensure that the fixed end of the LVDT can move horizontally on a plane perpendicular to the displacement variable component, so that the vertical distance can be accurately measured. However, if the pull rod drives the LVDT to move horizontally, a lateral force will be generated, causing the pull rod to bend and deform after long-term use. Although the existing universal joint can move in multiple directions, it is difficult to ensure that it is always flexible and that the LVDT is always perpendicular to the displacement variable component. Another way is to use a rebound LVDT to measure displacement, but the head of the existing rebound LVDT is a hard contact method, which will generate lateral friction during the measurement process, thereby causing the measuring rod to wear and bend, affecting the measurement accuracy.

[0007] Therefore, how to improve the detection accuracy and installation convenience of the expansion monitoring device is a technical problem that technical personnel in this field currently need to solve. Summary of the invention

[0008] The object of the present invention is to provide an expansion monitoring device, which can accurately obtain the expansion amount of a measuring point and improve the detection accuracy. Another object of the present invention is to provide an expansion monitoring system including the above expansion monitoring device.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] An expansion monitoring device comprises a detection component and a plurality of variable components installed on the detected object, wherein the detection component can obtain the displacement of the variable component; the detection component comprises a main frame, a probe bracket installed on the main frame, and a displacement sensor installed on the probe bracket; the number of the displacement sensors is at least three, and the displacement of the variable component in the X, Y, and Z directions is obtained respectively; the main frame comprises at least three plates perpendicular to each other, each of which is equipped with at least one probe bracket, one end of the probe bracket is adjustably arranged on the plate, and the displacement sensor is installed on the other end of the probe bracket.

[0011] Preferably, an arc groove is provided on the plate body, and a strip groove is provided on the probe bracket, and the length of the strip groove is greater than the radius of the arc groove; the probe bracket can swing along the arc groove, and the intersection of the arc groove and the strip groove can move along the extension direction of the strip groove.

[0012] Preferably, a center hole is provided on the plate body at the center of the arc-shaped groove, and the center hole is rotatably connected to the intersection of the strip groove of the probe bracket.

[0013] Preferably, the strip groove and the center hole are connected by a first connecting piece, and the intersection of the strip groove and the arc groove is connected by a second connecting piece.

[0014] Preferably, the plate body is a right-angled triangular plate body, and the right-angled sides of each right-angled triangular plate body are connected in sequence; a frame fixing rod is connected to the main frame; a triangular plane is provided at the intersection of the plates of the main frame, and the frame fixing rod is installed on the triangular plane; or, the frame fixing rod is installed at the connection of two right-angled triangular plates, and the extension direction of the frame fixing rod is parallel to the connection side

[0015] Preferably, the variable component includes a displacement variable block and a variable block fixing rod, and the variable block fixing rod is installed on the object to be detected; the displacement variable block is in a rectangular shape or is formed by three rectangular plates welded vertically in pairs, and the detection component is located at the corners of the displacement variable block, and the three surfaces at the corners of the displacement variable block correspond to at least one of the displacement sensors.

[0016] Preferably, the displacement sensor is a laser displacement sensor or an ultrasonic displacement sensor;

[0017] Alternatively, the displacement sensor is a rebound type linear displacement sensor, and a ball is provided at the end of the rebound type linear displacement sensor, and the ball abuts against the variable component.

[0018] An expansion monitoring system comprises an expansion monitoring device, wherein the expansion monitoring device is the above-mentioned expansion monitoring device.

[0019] Preferably, it also includes an expansion monitoring instrument for transmitting and displaying expansion data, wherein the expansion monitoring instrument can supply power to the displacement sensor and send out an alarm signal when the displacement sensor fails.

[0020] Preferably, it also includes a server and a controller, the expansion monitoring instrument is connected to the expansion monitoring device, the server and the controller, the server is used to convert the displacement into the expansion amount of the object to be detected, and the controller is used to obtain and store the temperature and pressure information of each monitoring point in the object to be detected and store the displacement.

[0021] The present invention also provides an expansion monitoring system, comprising any one of the above-mentioned expansion monitoring devices.

[0022] The expansion monitoring device provided by the present invention includes a detection component and several variable components installed on the object to be detected, and the detection component can obtain the displacement of the variable component; the detection component includes a main frame, a probe bracket installed on the main frame, and a displacement sensor installed on the probe bracket; the number of the displacement sensors is at least three, and the displacement of the variable component in the X, Y, and Z directions is obtained respectively; the main frame includes at least three plates perpendicular to each other, each of which is equipped with at least one probe bracket, one end of the probe bracket is adjustably arranged on the plate, and the displacement sensor is installed at the other end of the probe bracket. In the expansion monitoring device provided by the present invention, the variable component moves with the expansion of the object to be detected, and the detection component obtains the expansion of the object to be detected by obtaining the displacement of the variable component. At the same time, by obtaining the displacement of each variable component in the X, Y, and Z directions, the expansion of the object to be detected in different directions can be accurately obtained, thereby improving the expansion monitoring accuracy.

[0023] In a preferred embodiment, the variable component includes a displacement variable block and a variable block fixing rod, and the displacement block fixing rod is installed on the detected object; the displacement variable block is in the shape of a rectangular block or is formed by vertically welding three rectangular plates in pairs, and the detection component is located at the corners of the displacement variable block, and the three surfaces at the corners of the displacement variable block correspond to at least one displacement sensor. With the above arrangement, through the arrangement of the displacement variable block, it is only necessary to arrange the detection component at the corners of the displacement variable block, so as to accurately and efficiently obtain the displacement of the displacement variable block in the X, Y, and Z directions, which is convenient for installing the detection component.

[0024] The expansion monitoring system provided by the present invention is provided with the above-mentioned expansion monitoring device. Since the above-mentioned expansion monitoring device has the above-mentioned technical effects, the expansion monitoring system provided with the expansion monitoring device should also have corresponding technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the assembly structure of a specific implementation of the expansion monitoring device provided by the present invention;

[0027] Figure 2-1This is a schematic diagram of the external structure of the detection component in the expansion monitoring device provided by the present invention;

[0028] Figure 2-2 This is a schematic diagram of the internal structure of the detection component in the expansion monitoring device provided by the present invention;

[0029] Figure 2-3 This is a schematic diagram of the top structure of the detection component in the expansion monitoring device provided by the present invention;

[0030] Figure 2-4 It is a schematic diagram of the main structure of another specific implementation manner of the detection component in the expansion monitoring device provided by the present invention;

[0031] Figure 2-5 A schematic structural diagram of another specific implementation of a variable component in the expansion monitoring device provided by the present invention;

[0032] Figure 3 This is a schematic diagram of the structure of a probe bracket of a detection assembly in the expansion monitoring device provided by the present invention;

[0033] Figure 4 It is a structural schematic diagram of a rebound type linear displacement sensor of a detection component in the expansion monitoring device provided by the present invention;

[0034] Figure 5 A schematic diagram of the structure of the expansion monitoring system provided by the present invention;

[0035] Among them: detection component-100, main frame-101, probe bracket-102, frame fixing rod-103, first connecting piece-104, second connecting piece-105; variable component-200, displacement variable block-201, variable block fixing rod-202; displacement sensor-300, ball-301, server-400, controller-500. DETAILED DESCRIPTION

[0036] The core of the present invention is to provide an expansion monitoring device, which can accurately obtain the expansion amount of the measuring point and improve the detection accuracy. Another core of the present invention is to provide an expansion monitoring system including the above expansion monitoring device.

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Please refer to Figures 1 to 5 , Figure 1A schematic diagram of the assembly structure of a specific implementation of the expansion monitoring device provided by the present invention; Figure 2-1 This is a schematic diagram of the external structure of the detection component in the expansion monitoring device provided by the present invention; Figure 2-2 This is a schematic diagram of the internal structure of the detection component in the expansion monitoring device provided by the present invention; Figure 2-3 This is a schematic diagram of the top structure of the detection component in the expansion monitoring device provided by the present invention; Figure 2-4 It is a schematic diagram of the main structure of another specific implementation manner of the detection component in the expansion monitoring device provided by the present invention; Figure 2-5 A schematic structural diagram of another specific implementation of a variable component in the expansion monitoring device provided by the present invention; Figure 3 This is a schematic diagram of the structure of a probe bracket of a detection assembly in the expansion monitoring device provided by the present invention; Figure 4 It is a structural schematic diagram of a rebound type linear displacement sensor of a detection component in the expansion monitoring device provided by the present invention; Figure 5 This is a schematic diagram of the structure of the expansion monitoring system provided by the present invention.

[0039] In this embodiment, the expansion monitoring device includes a detection component 100 and a change component 200 .

[0040] Among them, the variable component 200 is installed on the object to be detected, and a number of expansion measurement points are set on the object to be detected. The variable component 200 is installed on each expansion measurement point. When the expansion measurement point of the object to be detected expands, the position of the variable component 200 will change accordingly. The detection component 100 obtains the expansion condition of the object to be detected by obtaining the displacement of the variable component 200.

[0041] Specifically, the detection assembly 100 includes a main frame 101, a probe bracket 102 and a displacement sensor 300. The main frame 101 is used to install the probe bracket 102, and the probe bracket 102 is used to install the displacement sensor 300. The displacement of the main frame 101 should be fixed. For example, the main frame 101 can be directly welded to the boiler steel frame, or it can be used as an extension component of the fixed part of the existing mechanical boiler expansion monitor and connected thereto; the number of displacement sensors 300 is at least three, which respectively obtain the displacement of the variable assembly 200 in the X, Y, and Z directions, so that the detection assembly 100 becomes a multi-dimensional displacement detection assembly 100, and the detection accuracy is improved.

[0042] Furthermore, the variable assembly 200 can be directly welded to the boiler expansion member, and can also be used as an extension member of the movable pointer portion of the original mechanical boiler expansion monitor and connected thereto.

[0043] Specifically, the object to be detected may be a boiler, or steam pipes, water supply pipes, and associated boxes and other ancillary equipment related to the boiler.

[0044] Furthermore, the main frame 101 includes at least three plates that are perpendicular to each other, and each plate has at least one probe bracket 102 hingedly connected. One end of the probe bracket 102 is adjustably arranged on the plate, and the displacement sensor 300 is installed at the other end of the probe bracket 102. After the probe bracket 102 is adjusted to the optimal position, it should be fixed to the main frame 101.

[0045] In the expansion monitoring device provided by the present invention, the variable component 200 moves along with the expansion of the detected object, and the detection component 100 obtains the expansion amount of the detected object by obtaining the displacement of the variable component 200. At the same time, by obtaining the displacement of each variable component 200 in the X, Y, and Z directions, the expansion amount of the detected object in different directions can be accurately obtained, thereby improving the expansion monitoring accuracy.

[0046] On the basis of the above embodiments, an arc groove is opened on the plate body, and a strip groove is provided on the probe bracket 102, and the length of the strip groove is greater than the radius of the arc groove; the probe bracket 102 can swing along the arc groove, and the intersection of the arc groove and the strip groove can move along the extension direction of the strip groove.

[0047] With such a configuration, the angle adjustment of the probe bracket 102 and the adjustment of the relative displacement with the main frame 101 can be achieved, and then the position of the displacement sensor 300 can be adjusted, so that the displacement sensor 300 is in the best detection position.

[0048] Furthermore, a center hole is provided on the plate at the center of the arc groove, and the intersection of the center hole and the strip groove of the probe bracket 102 can be rotatably connected to facilitate the swing of the probe bracket 102 to achieve angle adjustment.

[0049] Preferably, the strip groove and the center hole are fixed by a first connecting member 104, and the intersection of the strip groove and the arc groove is fixed by a second connecting member 105. Preferably, the first connecting member 104 and the second connecting member 105 are both matching members of a screw and a nut.

[0050] On the basis of the above embodiments, the plate body is a right-angled triangle plate body, and the right-angled sides of each right-angled triangle plate body are connected in sequence; a triangular plane is provided at the intersection of the plates of the main frame 101, and a frame fixing rod 103 is provided on the triangular plane.

[0051] Alternatively, the frame fixing rod 103 is installed at the connection between the two right-angled triangular plates, and the extension direction of the frame fixing rod 103 is parallel to the connection edge, such as Figure 2-4 Of course, the frame fixing rod 103 can also be installed at other positions. In this embodiment, the intersection of the plates of the main frame 101 does not need to be provided with a triangular plane.

[0052] Specifically, the main frame 101 serves as a fixed bracket of the multi-dimensional displacement sensor 300, and includes three mutually perpendicular right-angled metal plates to form the main frame 101. The three metal plates are rigidly welded, that is, three right-angled triangles are welded together. An arc groove is designed on each metal plate, and a center hole is opened at the center position of the arc groove, and a probe bracket 102 is installed on each of them. The probe bracket 102 is used to install the displacement sensor 300 thereon. Specifically, the displacement sensor 300 can be fixed thereon by screws, or by other methods, depending on the structure of the displacement sensor 300, but the displacement sensor 300 should be perpendicular to the corresponding surface of the displacement change block 201. A rectangular groove is designed at the fixed end of the probe bracket 102, and the intersection of the three metal plates of the main frame 101 is designed as follows Figure 2-3 The triangular plane shown in the figure is welded with a metal rod, namely, a frame fixing rod 103, which is used to fix the main frame 101 on the target component. In addition to being able to rotate around the center hole, the probe bracket 102 can also adjust the front and rear positions. When the position of the probe bracket 102 is determined, the probe bracket 102 can be fixed to the main frame 101 through the first connecting member 104 and the first connecting member 104; the specific method is: insert a screw into the intersection of the center hole of the main frame 101 and the rectangular groove of the probe bracket 102, insert another screw into the intersection of the rectangular groove of the probe bracket 102 and the arc groove of the main frame 101, and tighten the two screws with two nuts respectively. When the position of the probe bracket 102 needs to be adjusted, just loosen the two nuts.

[0053] On the basis of the above embodiments, the displacement changing assembly 200 includes a displacement changing block 201 and a displacement changing block fixing rod 202, and the displacement changing block fixing rod 202 is installed on the object to be detected; the displacement changing block 201 is in a rectangular shape, such as Figure 1 As shown, or it can be made of three rectangular plates welded vertically in pairs, as shown in Figure 2-5 As shown, the detection component 100 is located at the corner of the displacement changing block 201 , and the three surfaces at the corner of the displacement changing block 201 correspond to at least one displacement sensor 300 .

[0054] Preferably, the multi-dimensional displacement changing block 201 is a rectangular or cubic hollow metal block. Of course, it can also be a structure in other forms that can form three mutually perpendicular surfaces. A metal rod is welded at the center of a plane of the displacement changing block 201 to fix the displacement changing block 201 on the target component. When the displacement changing block 201 is composed of three rectangular plates welded vertically in pairs, a metal rod can be welded at one of the connections.

[0055] With the above arrangement, through the arrangement of the displacement changing block 201 , it is only necessary to arrange the detection component 100 at the corners of the displacement changing block 201 , so as to accurately and efficiently obtain the displacement of the displacement changing block 201 in the X, Y, and Z directions, thereby facilitating the installation of the detection component 100 .

[0056] Based on the above embodiments, the displacement sensor 300 is a non-contact sensor such as a laser displacement sensor or an ultrasonic displacement sensor. Of course, the displacement sensor 300 can also be a rebound linear displacement sensor. A ball is provided at the end of the rebound linear displacement sensor, and the ball abuts against the variable component 200.

[0057] Specifically, the displacement sensor 300 is mounted on the probe bracket 102 of the main frame 101, and the displacement sensor 300 can be a rebound LVDT. The rebound LVDT provided in this embodiment has a fixed end fixed on the probe bracket 102, and the position is fixed and unchanged. The rebound pull rod is close to one side of the displacement change block 201 and remains vertical. Since the expansion change block is generally installed at the four corners of the boiler during the expansion of the boiler, there is no rotational displacement in the expansion at this location, so it always remains vertical to the probe bracket 102 of the displacement measurement device. When the boiler expands unevenly, the expansion block will have a rotational displacement, but the displacement is very small, and the probe bracket 102 is expected to still be approximately vertical, so the impact on the measurement result is very small and can be ignored. In order to ensure that the contact surface between the pull rod and the displacement change block 201 does not produce hard destructive friction, a ball 301 is added to the pull rod head to meet the requirement that the displacement change block 201 has lateral movement, and the probe rod head is designed in the form of a ball 301 to avoid deformation of the pull rod caused by strong lateral friction. At this time, although the displacement changing block 201 has undergone lateral displacement, the pull rod is always perpendicular to its plane, thereby eliminating equipment wear and pull rod deformation caused by hard friction when the horizontal position changes; the above arrangement is not only easy to install and simple in structure, but also can always keep the LVDT and the surface of the displacement changing block 201 perpendicular, ensuring measurement accuracy.

[0058] The multi-dimensional expansion monitoring device provided in this embodiment is easy to install and can easily perform signal debugging. At the same time, the signal transmission is diverse, which is convenient for the integration of monitoring signals of a large number of expansion measurement points. In addition, the use of on-site multi-dimensional expansion monitoring instruments and field bus technology greatly reduces the number of cables and construction costs, thereby greatly reducing the construction cost of the boiler expansion monitoring system and creating conditions for the practical application of this technology.

[0059] In addition to the above-mentioned expansion monitoring device, the present invention also provides an expansion monitoring system including the above-mentioned expansion monitoring device.

[0060] Furthermore, the expansion monitoring system also includes an expansion monitoring instrument for transmitting and displaying expansion data, the expansion data being the expansion data detected by the displacement sensor 300. The expansion monitoring instrument can supply power to the displacement sensor 300 and send out an alarm signal when the displacement sensor 300 fails, thereby facilitating timely maintenance and replacement of the displacement sensor 300 and improving detection accuracy.

[0061] Furthermore, the expansion monitoring system also includes a server 400 and a controller 500. The expansion monitoring instrument is connected to the expansion monitoring device, the server 400 and the controller 500. The server 400 is used to convert the displacement into the expansion of the object to be detected, and the controller 500 is used to obtain and store the temperature and pressure information of each monitoring point in the object to be detected and store the displacement.

[0062] Specifically, the expansion monitoring instrument, as a displacement collection, display and communication instrument, can provide power for the three displacement sensors 300 corresponding to the expansion monitoring points, and collect the displacement vector signals measured by each displacement sensor 300 into the expansion monitoring instrument. The expansion monitoring instrument can achieve the following functions:

[0063] 1. The function of digital display of displacement vector signals of each channel. It can be displayed simultaneously or cyclically;

[0064] 2. The function of integrating the displacement vector signals of each channel into the total displacement signal and displaying it;

[0065] 3. The function of outputting each displacement vector signal as a 4-20mA current signal;

[0066] 4. The function of communicating with computers, DCS control systems, PLC control systems, etc. using a variety of fieldbus protocols, such as the Foundation Fieldbus protocol FF, HART protocol, etc.

[0067] 5. It has the function of sensor failure alarm. It can alarm the sensor failure at a specific position of the instrument and send the alarm signal to the detection system through the communication network.

[0068] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0069] The above is a detailed introduction to the expansion monitoring device provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An expansion monitoring device, characterized in that: The invention comprises a detection component (100) and a plurality of variable components (200) mounted on a detected object, wherein the detection component (100) is used to obtain the displacement of the variable component (200); the detection component (100) comprises a main frame (101), a probe bracket (102) mounted on the main frame (101), and a displacement sensor (300) mounted on the probe bracket (102); the number of the displacement sensors (300) is at least three, and the displacements of the variable component (200) in the X, Y and Z directions are obtained respectively; the main frame (101) comprises at least three plates which are perpendicular to each other, each of which is mounted with at least one probe bracket (102), one end of which is adjustably arranged on the plate, and the displacement sensor (300) is mounted on the other end of the probe bracket (102); The detection component (100) is located outside the moving component (200), and the probe bracket (102) is located outside the main frame (101); The plate body is provided with an arc-shaped groove, the probe support (102) is provided with a strip-shaped groove, the length of the strip-shaped groove being greater than the radius of the arc-shaped groove; the probe support (102) can swing along the arc-shaped groove, and the intersection of the arc-shaped groove and the strip-shaped groove can move along the extension direction of the strip-shaped groove; A center hole is provided on the plate body at the center of the arc-shaped groove, and the center hole is rotatably connected to the intersection of the strip groove of the probe bracket (102); The strip groove and the circular center hole are connected via a first connecting piece (104), and the intersection of the strip groove and the arc groove is connected via a second connecting piece (105).

2. The expansion monitoring device according to claim 1, characterized in that: The plate body is a right-angled triangular plate body, and the right-angled sides of each right-angled triangular plate body are connected in sequence; a frame fixing rod (103) is connected to the main frame; a triangular plane is provided at the intersection of the plates of the main frame (101), and the frame fixing rod (103) is installed on the triangular plane; or, the frame fixing rod (103) is installed at the connection of two right-angled triangular plate bodies, and the extension direction of the frame fixing rod (103) is parallel to the connection side.

3. The expansion monitoring device according to claim 1 or 2, characterized in that: The variable component (200) comprises a displacement variable block (201) and a variable block fixing rod (202), wherein the displacement variable block fixing rod (202) is mounted on the detected object; the displacement variable block (201) is in the shape of a rectangular parallelepiped or is formed by vertically welding three rectangular plates in pairs; the detection component (100) is located at the corners of the displacement variable block (201); and at least one displacement sensor (300) corresponds to three surfaces at the corners of the displacement variable block (201).

4. The expansion monitoring device according to claim 1 or 2, characterized in that: The displacement sensor (300) is a laser displacement sensor or an ultrasonic displacement sensor; Alternatively, the displacement sensor (300) is a rebound-type linear displacement sensor, and a ball is provided at the end of the rebound-type linear displacement sensor, and the ball abuts against the variable component (200).

5. An expansion monitoring system, comprising an expansion monitoring device, characterized in that: The expansion monitoring device is the expansion monitoring device according to any one of claims 1 to 4.

6. The expansion monitoring system according to claim 5, characterized in that It also comprises an expansion monitoring instrument for transmitting and displaying expansion data, wherein the expansion monitoring instrument is used to supply power to the displacement sensor (300) and to send out an alarm signal when the displacement sensor (300) fails.

7. The expansion monitoring system according to claim 6, characterized in that It also includes a server (400) and a controller (500), wherein the expansion monitoring instrument is connected to the expansion monitoring device, the server (400) and the controller (500), the server (400) is used to convert the displacement into the expansion of the object to be detected, and the controller (500) is used to obtain and store the temperature and pressure information of each monitoring point in the object to be detected and store the displacement.

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