Boiler expansion amount detection method
By constructing a virtual three-dimensional coordinate system and setting a reference point on the rigid support structure of the boiler, and using a non-contact ranging unit and a sensing target, the problems of complex and low reliability of existing detection methods are solved, and flexible and accurate expansion detection is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-26
- Publication Date
- 2026-04-03
AI Technical Summary
Existing methods for detecting boiler expansion rely excessively on specific measurement channels, resulting in complex implementation processes and low reliability in complex environments.
A virtual three-dimensional coordinate system was constructed on the rigid support structure of the boiler, three non-collinear reference points were set, and the expansion amount was determined by geometric calculation using a non-contact ranging unit and a sensing target.
It improves the flexibility of expansion monitoring point placement and the reliability of detection, reduces dependence on specific directions, and ensures measurement accuracy and stability in complex environments.
Smart Images
Figure CN121782983A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of power plant boiler testing technology, specifically relating to a method for detecting boiler expansion. Background Technology
[0002] With the widespread application of high-parameter, large-capacity power plant boilers, their thermal systems have become increasingly complex. High-temperature, high-pressure steam and water pipelines operate at the limits of material tolerances, making the monitoring of their health status particularly crucial. Especially in recent years, with the increased depth and frequency of power grid peak shaving, the displacement and vibration of critical monitored components such as the boiler body, superheater / reheater steam pipelines, and headers have gradually increased. Some units have even begun to show signs of endangering the boiler body and connected equipment. Therefore, it is necessary to utilize intelligent methods to closely monitor critical components and provide a basis for safety assessments.
[0003] Current online expansion monitoring technologies are rapidly developing, primarily including image recognition-based online expansion indicators, displacement-based (pull-rope) expansion indicators, and laser-based online expansion indicators. Image recognition-based online expansion indicators simply add an image recognition system to the original mechanical expansion method. This method is highly dependent on the image recognition system; if the indicator is blurry, the image recognition will fail. Displacement-based (pull-rope) expansion indicators are similar to traditional expansion indicators, using tension signals to represent position signals. This method has high requirements for installation location. Laser-based online expansion indicators use laser ranging to represent three-dimensional position, requiring a large reflective surface, and also have high requirements for installation location. Therefore, existing detection methods suffer from problems such as over-reliance on dedicated measurement channels, leading to complex implementation processes and low reliability in the complex environment of boiler surfaces. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for detecting boiler expansion, which solves the problems of existing detection methods that rely excessively on special measurement channels, resulting in complex implementation processes and low detection reliability in the complex environment of the boiler surface.
[0005] The objective of this invention can be achieved through the following technical solutions: A method for detecting boiler expansion includes the following steps: Obtain at least one expansion monitoring point on the boiler to detect thermal expansion; Based on the rigid support structure of the boiler, a virtual three-dimensional coordinate system is constructed for each expansion monitoring point, and three non-collinear reference points with known coordinates are preset. Non-contact ranging units are deployed at each reference point; The distance between the expansion monitoring point and each reference point is obtained in real time through a non-contact ranging unit; Based on the real-time measurement interval and the coordinates of each reference point, the initial three-dimensional coordinates of the expansion monitoring point before expansion and the real-time three-dimensional coordinates after expansion are obtained through geometric calculations. Based on the differences between the initial three-dimensional coordinates and the corresponding coordinate axes of the real-time three-dimensional coordinates, the three-dimensional expansion amount of the corresponding expansion monitoring point is determined.
[0006] Furthermore, each expansion monitoring point is equipped with a sensing target adapted to the non-contact ranging unit.
[0007] Furthermore, the non-contact ranging unit is an electromagnetic distance sensor; The sensing target is a permanent magnet fixed on the expansion monitoring point.
[0008] Furthermore, the following conditions must be met when constructing a virtual three-dimensional coordinate system: In the virtual three-dimensional coordinate system, the positive directions of the X-axis, Y-axis, and Z-axis are all the same as the directions of the expected thermal expansion components of the expansion monitoring point on the corresponding axes; The expansion monitoring point is located in the first quadrant formed by the positive X-axis, positive Y-axis and positive Z-axis.
[0009] Furthermore, when setting three non-collinear reference points with known coordinates, the following conditions must be met: Set a reference point at the origin of the virtual three-dimensional coordinate system; The other two reference points are located on different coordinate axes, and the coordinate values of the reference points on the corresponding coordinate axes are less than the coordinate values of the expansion monitoring points on the corresponding coordinate axes before expansion.
[0010] Furthermore, the three reference points are, in order, the first reference point (0, 0, 0), the second reference point (0, y, 0), and the third reference point (0, 0, z).
[0011] Furthermore, based on the real-time measured spacing and coordinates of each reference point, the initial three-dimensional coordinates of the expansion monitoring point before expansion and the real-time three-dimensional coordinates after expansion are obtained through geometric calculations, specifically including the following steps: Assuming the three-dimensional coordinates of the expansion monitoring point at any given time are (A, B, C), and the measurement distances between the expansion monitoring point and the first, second, and third reference points are L, M, and N respectively, then the following expression is satisfied: Solving the above expressions simultaneously, we obtain: Substituting the measurement distances between the expansion monitoring point before expansion and the first, second, and third reference points, the initial three-dimensional coordinates (A0, B0, C0) can be obtained. Substituting the measurement distances between the expansion monitoring point and the first, second, and third reference points after expansion, the real-time three-dimensional coordinates can be obtained as (A i B i C i ).
[0012] The beneficial effects of this invention are: This invention establishes a stable spatial measurement benchmark by constructing a virtual three-dimensional coordinate system on the rigid support structure of the boiler and setting three non-collinear reference points. This eliminates the dependence on specific directions or visual channels for expansion monitoring points. Non-contact ranging units deployed on the three reference points are used to obtain the distance between the reference points and the expansion monitoring points. Based on geometric calculations, the initial and real-time three-dimensional coordinates of the expansion monitoring points are determined, transforming complex physical displacement monitoring into stable spatial mathematical calculations. This improves the flexibility of expansion monitoring point placement, as the non-contact ranging units only need to be installed on the rigid support structure around the expansion monitoring points. Finally, the three-dimensional expansion amount is determined based on the differences between the initial and real-time three-dimensional coordinates on each coordinate axis. This effectively solves the problems of existing detection methods, which rely too heavily on specific measurement channels, leading to complex implementation processes and low reliability in the complex environment of the boiler surface. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0014] Figure 1 This is a schematic diagram of the overall process of the boiler expansion detection method of the present invention. Detailed Implementation
[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0016] like Figure 1 As shown, a method for detecting boiler expansion includes the following steps: Obtain at least one expansion monitoring point on the boiler to detect thermal expansion; Based on the rigid support structure of the boiler, a virtual three-dimensional coordinate system is constructed for each expansion monitoring point, and three non-collinear reference points with known coordinates are preset. Non-contact ranging units are deployed at each reference point; The distance between the expansion monitoring point and each reference point is obtained in real time through a non-contact ranging unit; Based on the real-time measurement interval and the coordinates of each reference point, the initial three-dimensional coordinates of the expansion monitoring point before expansion and the real-time three-dimensional coordinates after expansion are obtained through geometric calculations. Based on the differences between the initial three-dimensional coordinates and the corresponding coordinate axes of the real-time three-dimensional coordinates, the three-dimensional expansion amount of the corresponding expansion monitoring point is determined.
[0017] Each expansion monitoring point is equipped with an inductive target that is compatible with the non-contact ranging unit. The inductive target provides a stable measurement benchmark for ranging, effectively overcoming the interference of the boiler's complex metallic background and component surface conditions on the measurement, and ensuring the accuracy and stability of the distance measurement signal.
[0018] Preferably, the rigid support structure of the boiler includes steel beams for fixing the boiler. When the boiler expands due to heat, its position is equivalent to an expansion monitoring point and remains stable, serving as a spatial viewing reference for installing a non-contact ranging unit.
[0019] This invention establishes a stable spatial measurement benchmark by constructing a virtual three-dimensional coordinate system on the rigid support structure of the boiler and setting three non-collinear reference points. This eliminates the dependence on specific directions or visual channels for expansion monitoring points. Non-contact ranging units deployed on the three reference points are used to obtain the distance between the reference points and the expansion monitoring points. Based on geometric calculations, the initial and real-time three-dimensional coordinates of the expansion monitoring points are determined, transforming complex physical displacement monitoring into stable spatial mathematical calculations. This improves the flexibility of expansion monitoring point placement, as the non-contact ranging units only need to be installed on the rigid support structure around the expansion monitoring points. Finally, the three-dimensional expansion amount is determined based on the differences between the initial and real-time three-dimensional coordinates on each coordinate axis. This effectively solves the problems of existing detection methods, which suffer from complex implementation processes due to excessive reliance on specific measurement channels and low reliability in the complex environment of the boiler surface.
[0020] The non-contact ranging unit is an electromagnetic distance sensor; The sensing target is a permanent magnet fixed on the expansion monitoring point; The permanent magnet is firmly attached to the boiler by magnetic force, enabling rapid installation of the sensing target without the need for welding or drilling, thus avoiding damage to the boiler itself. At the same time, the strong magnetism of the permanent magnet can provide a stable and strong alternating magnetic field disturbance signal for the electromagnetic distance sensor, effectively enhancing the measurement signal strength and signal-to-noise ratio, and significantly improving ranging accuracy and anti-interference capability.
[0021] To facilitate calculations and avoid multiple solutions caused by exponentiation, the following conditions must be met when constructing a virtual 3D coordinate system: In the virtual three-dimensional coordinate system, the positive directions of the X-axis, Y-axis, and Z-axis are all the same as the directions of the expected thermal expansion components of the expansion monitoring point on the corresponding axes; The expansion monitoring point is located in the first quadrant formed by the positive X-axis, positive Y-axis, and positive Z-axis. When setting three non-collinear reference points with known coordinates, the following conditions must be met: Set a reference point at the origin of the virtual three-dimensional coordinate system; The other two reference points are located on different coordinate axes, and the coordinate values of the reference points on the corresponding coordinate axes are less than the coordinate values of the expansion monitoring points on the corresponding coordinate axes before expansion.
[0022] The three reference points are, in order, the first reference point (0, 0, 0), the second reference point (0, y, 0), and the third reference point (0, 0, z).
[0023] Based on the real-time measured spacing and coordinates of each reference point, the initial three-dimensional coordinates of the expansion monitoring point before expansion and the real-time three-dimensional coordinates after expansion are obtained through geometric calculations. The specific steps include: Assuming the three-dimensional coordinates of the expansion monitoring point at any given time are (A, B, C), and the measurement distances between the expansion monitoring point and the first, second, and third reference points are L, M, and N respectively, then the following expression is satisfied: Solving the above expressions simultaneously, we obtain: Substituting the measurement distances between the expansion monitoring point before expansion and the first, second, and third reference points, the initial three-dimensional coordinates (A0, B0, C0) can be obtained. Substituting the measurement distances between the expansion monitoring point and the first, second, and third reference points after expansion, the real-time three-dimensional coordinates can be obtained as (A i B i C i ); Based on the differences between the initial and real-time 3D coordinates along each axis, the 3D expansion amount at the corresponding expansion monitoring point is determined as follows: The X-axis expansion is: A i -A0; The Y-axis expansion is: B i -B0; The Z-axis expansion is: Ci -C0.
[0024] This application also provides a boiler expansion monitoring and indication system, including a monitoring module and an early warning module. The monitoring module is used to execute a boiler expansion detection method and output the expansion amount of each shaft. The early warning module is connected to the monitoring module to receive the expansion amount of each axis output by the monitoring module and set corresponding thresholds for the expansion amount of each axis. When the expansion amount of any axis exceeds the threshold, the early warning module issues an alarm signal to remind the operator. Preferably, the early warning module includes a threshold storage unit, a comparison unit, and an alarm. The threshold storage unit can be an EEPROM chip or a Flash chip; The comparison unit is implemented by running a comparison program on the MCU or CPU; The alarm can be either a buzzer or an LED indicator.
[0025] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0026] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.
Claims
1. A method for detecting boiler expansion, characterized in that, Includes the following steps: Obtain at least one expansion monitoring point on the boiler to detect thermal expansion; Based on the rigid support structure of the boiler, a virtual three-dimensional coordinate system is constructed for each expansion monitoring point, and three non-collinear reference points with known coordinates are preset. Non-contact ranging units are deployed at each reference point; The distance between the expansion monitoring point and each reference point is obtained in real time through a non-contact ranging unit; Based on the real-time measurement interval and the coordinates of each reference point, the initial three-dimensional coordinates of the expansion monitoring point before expansion and the real-time three-dimensional coordinates after expansion are obtained through geometric calculations. Based on the differences between the initial three-dimensional coordinates and the corresponding coordinate axes of the real-time three-dimensional coordinates, the three-dimensional expansion amount of the corresponding expansion monitoring point is determined.
2. The boiler expansion detection method according to claim 1, characterized in that, Each expansion monitoring point is equipped with a sensor target adapted to the non-contact ranging unit.
3. The boiler expansion detection method according to claim 2, characterized in that, The non-contact ranging unit is an electromagnetic distance sensor; the sensing target is a permanent magnet fixed on the expansion monitoring point.
4. The boiler expansion detection method according to claim 3, characterized in that, The following conditions must be met when constructing a virtual 3D coordinate system: In the virtual three-dimensional coordinate system, the positive directions of the X-axis, Y-axis, and Z-axis are all the same as the directions of the expected thermal expansion components of the expansion monitoring point on the corresponding axes; The expansion monitoring point is located in the first quadrant formed by the positive X-axis, positive Y-axis and positive Z-axis.
5. The boiler expansion detection method according to claim 4, characterized in that, When setting three non-collinear reference points with known coordinates, the following conditions must be met: Set a reference point at the origin of the virtual three-dimensional coordinate system; The other two reference points are located on different coordinate axes, and the coordinate values of the reference points on the corresponding coordinate axes are less than the coordinate values of the expansion monitoring points on the corresponding coordinate axes before expansion.
6. The boiler expansion detection method according to claim 5, characterized in that, The three reference points are, in order, the first reference point (0, 0, 0), the second reference point (0, y, 0), and the third reference point (0, 0, z).
7. The boiler expansion detection method according to claim 6, characterized in that, Based on the real-time measured spacing and coordinates of each reference point, the initial three-dimensional coordinates of the expansion monitoring point before expansion and the real-time three-dimensional coordinates after expansion are obtained through geometric calculations. The specific steps include: Assuming the three-dimensional coordinates of the expansion monitoring point at any given time are (A, B, C), and the measurement distances between the expansion monitoring point and the first, second, and third reference points are L, M, and N respectively, then the following expression is satisfied: A 2 +B 2 +C 2 =L 2 A 2 +(B-y) 2 +C 2 =M 2 A 2 +B 2 +(C-z) 2 =N 2 Solving the above expressions simultaneously, we obtain: Substituting the measurement distances between the expansion monitoring point before expansion and the first, second, and third reference points, the initial three-dimensional coordinates (A0, B0, C0) can be obtained. Substituting the measurement distances between the expansion monitoring point and the first, second, and third reference points after expansion, the real-time three-dimensional coordinates can be obtained as (A i B i C i ).