A rotary kiln non-contact deformation monitoring system and method

Abstract

This invention discloses a non-contact deformation monitoring system and method for rotary kilns. It includes: a pulsed laser emitting module for irradiating the operating rotary kiln cylinder with a time-domain encoded pulsed laser beam at a low swoop angle; an optical edge enhancement module for multiple reflections and refractions of the original contour light formed by the pulsed laser beam on the cylinder surface; a CCD synchronous acquisition module for receiving the contour light signal processed by the optical edge enhancement module and outputting a digital image; and an image processing and deformation calculation unit for performing edge extraction and reconstructing the current contour model from the digital image to obtain the cylinder deformation. An alarm is triggered when the deformation exceeds a set safety threshold. The entire system of this invention has no physical connection to the kiln body, completely avoiding the influence of high temperature and vibration on the sensors. Furthermore, it is designed to monitor small deformations in the early stages of material creep, supporting long-term tracking of slow deformations at the millimeter level, enabling pre-failure prediction, and improving safety and service life.

Description

Technical Field

[0001] This invention relates to a rotary kiln deformation monitoring technology, and in particular to a non-contact deformation monitoring system and method for rotary kilns. Background Technology

[0002] Rotary kilns operate continuously under high temperature (800℃) and strong vibration conditions for extended periods. Due to their immense weight and load, the kiln shell is prone to minute but cumulative deformation under creep and alternating stress. Existing monitoring methods have the following shortcomings: 1. Traditional methods for monitoring the deformation of rotary kilns mainly include geometric leveling, side leveling, fitting and solving spatial circles, and three-dimensional laser scanning. These methods require complex measurements and tedious manual data processing, have low automation, and are difficult to meet the needs of real-time and accurate measurement.

[0003] 2. Most existing measurement methods can only obtain static data. When the rotary kiln is in normal operation, the center line of the kiln shaft will inevitably change under the action of high temperature and material load, making it difficult to truly reflect the situation of the kiln shaft center line during dynamic operation.

[0004] 3. Traditional contact measurement methods suffer from poor accuracy, complex operation, and limited application scenarios, making them unable to meet the needs of three-dimensional measurement and difficult to adapt to measurement requirements in high-temperature and vibration environments.

[0005] 4. Existing rotary kiln deformation monitoring methods are insufficient in terms of anti-interference capabilities and lack highly reliable, low-noise, and accurate measurements to ensure the accuracy and efficiency of the measurements.

[0006] 5. Current measurement systems still need improvement in data acquisition, cannot guarantee the accuracy of the acquired data, and lack direct methods for hardware improvement. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of existing calibration technology and provide a reasonable, non-contact, and accurate non-contact deformation monitoring system and method for rotary kilns.

[0008] The technical solution of this invention is: A non-contact deformation monitoring system for rotary kilns, characterized by comprising: A pulsed laser emitting module is used to irradiate the operating rotary kiln shell with a time-domain encoded pulsed laser beam at a low swoop angle. The optical edge enhancement module includes a prism-cylindrical lens group, which reflects and refracts the original contour light formed by the pulsed laser beam on the surface of the cylinder multiple times to enhance the light intensity distribution at the edge of the cylinder. The CCD synchronous acquisition module is used to receive the contour light signal processed by the optical edge enhancement module and output a digital image. The image processing and deformation calculation unit is connected to the CCD synchronous acquisition module. It is used to perform edge extraction and reconstruction of the current contour model on the digital image, and compare the current contour model with the pre-stored standard contour model through the calibrated world coordinate system to obtain the radial and / or axial deformation of the cylinder. An alarm output interface is used to issue an alarm signal when the deformation exceeds a set safety threshold. The pulsed laser emission module, optical edge enhancement module, and CCD synchronous acquisition module have no mechanical contact with the rotary kiln body.

[0009] Furthermore: the pulsed laser emitting module further includes: A frequency encoder is used to adaptively adjust the pulse repetition frequency according to the real-time rotation speed of the rotary kiln, so that the laser pulse corresponds one-to-one with the sampling point on the surface of the cylinder.

[0010] Furthermore, the edge extraction algorithm executed by the image processing and deformation resolution unit includes, in sequence: Noise filtering, threshold segmentation, mathematical morphology refinement and concatenation, and temporal coding storage.

[0011] Furthermore, the calibrated world coordinate system is established in the following way: At least six non-coplanar feature points are arranged around the kiln body using standard calibration objects of known size. The camera's intrinsic and extrinsic parameters are calculated using feature point images acquired by CCD to achieve millimeter-level precision coordinate mapping.

[0012] Furthermore, the alarm output interface outputs deformation reports at a cycle of ≤1 minute and supports trend curve display and predictive maintenance prompts.

[0013] A non-contact deformation monitoring method for rotary kilns includes the following steps: S1. Initialization steps: Set the measurement frequency, pulse laser wavelength, pulse width, emission angle, and edge extraction threshold according to the rotary kiln's operating status. S2. Contour acquisition steps: S201. Irradiate the rotating kiln cylinder in operation with a time-domain encoded pulsed laser beam at a low swoop angle; S202. Use a prism-cylindrical lens group to reflect and refract the light reflected from the surface of the cylinder multiple times to enhance the light intensity of the edge contour. S203. Synchronously acquire enhanced contour images using a CCD; S3. Image processing steps: Perform edge extraction on the contour image and reconstruct the current cylinder contour model; S4. Deformation calculation steps: Compare the current cylinder profile model with the pre-stored standard profile model in the calibrated world coordinate system, and calculate the radial and / or axial deformation. S5. Alarm procedure: If the deformation exceeds the set safety threshold, an alarm signal is issued. All of the above steps are completed non-contactly while the rotary kiln is operating at high temperature.

[0014] Further: In step S1, the measurement frequency is adjusted in real time according to the rotation speed of the rotary kiln, so that the angle between sampling points on the same circumference of the cylinder surface is ≤0.5°.

[0015] Further: In step S3, the edge extraction sequentially includes: Gaussian filtering for noise reduction, adaptive threshold segmentation, morphological thinning and breakpoint connection to obtain single-pixel level continuous edges.

[0016] Further: In step S4, the calibrated world coordinate system is calibrated by setting up calibration objects with known three-dimensional coordinates on site and using a CCD imaging model to calibrate the camera's intrinsic and extrinsic parameters, with a calibration error ≤0.5mm.

[0017] Furthermore, after step S5, the following is also included: S6. Store the deformation amounts of each time in a time series, generate a creep trend curve, and issue a failure warning in advance when the deformation rate suddenly increases.

[0018] The beneficial effects of this invention are: 1. This invention achieves millimeter-level deformation resolution by using an coded light source, edge enhancement, and a calibrated coordinate system. It can capture minute deformations in the early stages of material creep, thus achieving high-precision monitoring.

[0019] 2. This invention adopts non-contact, remote deployment, has a certain anti-interference capability, strong environmental adaptability, and realizes continuous monitoring of the entire field. It can monitor the circumference of the rotary kiln without blind spots and has a simple structure and low cost.

[0020] 3. This invention has strong real-time early warning capabilities. The system can output a deformation report every minute, support trend analysis and threshold alarms, and assist in predictive maintenance.

[0021] 4. This invention uses a pulsed laser source with specific frequency encoding, combined with synchronous acquisition, to effectively suppress ambient light and dust scattering noise and improve the signal-to-noise ratio; and introduces an edge enhancement optical structure composed of prisms / cylindrical lenses to significantly enhance the edge signal of the cylinder contour, which facilitates high-precision edge extraction. 5. This invention eliminates the need for personnel to climb or get close to the high-temperature cylinder for operation, reducing operational risks and ensuring high safety. Furthermore, the entire process from data acquisition and processing to early warning is completed automatically, resulting in a high degree of automation, low labor costs, ease of promotion and implementation, and good economic benefits. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a non-contact deformation monitoring system for a rotary kiln. Figure 2 for Figure 1 The figure shows a side view of a non-contact deformation monitoring system for a rotary kiln. Figure 3 for Figure 1 The diagram shows a top view of a non-contact deformation monitoring system for a rotary kiln. Detailed Implementation

[0023] Example: See Figure 1 -- Figure 3 In the figure, 1-support roller mechanism, 2-kiln cylinder, 3-heating mechanism, 4-deformation monitoring mechanism, 5-CCD observation module, 6-optical edge enhancement module, 7-pulse laser emission module.

[0024] The rotary kiln includes a feeding device, a support roller mechanism 1, a drive mechanism, a kiln cylinder 2, and a discharge device. The kiln cylinder 2 is provided with a heating section and a cooling section. A heating mechanism 3 is provided around the heating section. The heating mechanism 3 includes a heating hood and a heater. The heating hood can cover the kiln cylinder 2. The heater is located inside the heating hood (not shown in the figure, this is prior art and will not be described in detail). A deformation monitoring mechanism 4 is provided on the heating hood. The deformation monitoring mechanism 4 includes a CCD observation module 5, an optical edge enhancement module 6, and a pulsed laser emission module 7.

[0025] A non-contact deformation monitoring system for rotary kilns, characterized by comprising: A pulsed laser emitting module is used to irradiate the operating rotary kiln shell with a time-domain encoded pulsed laser beam at a low swoop angle. The optical edge enhancement module includes a prism-cylindrical lens group, which reflects and refracts the original contour light formed by the pulsed laser beam on the surface of the cylinder multiple times to enhance the light intensity distribution at the edge of the cylinder. The CCD synchronous acquisition module is used to receive the contour light signal processed by the optical edge enhancement module and output a digital image. The image processing and deformation calculation unit is connected to the CCD synchronous acquisition module. It is used to perform edge extraction and reconstruction of the current contour model on the digital image, and compare the current contour model with the pre-stored standard contour model through the calibrated world coordinate system to obtain the radial and / or axial deformation of the cylinder. An alarm output interface is used to issue an alarm signal when the deformation exceeds a set safety threshold. The pulsed laser emitting module, the optical edge enhancement module, and the CCD synchronous acquisition module have no mechanical contact with the rotary kiln body and are arranged as a whole at a distance of ≥3m outside the kiln body.

[0026] Preferred option: The 7 pulsed laser emitting modules further include: A frequency encoder is used to adaptively adjust the pulse repetition frequency according to the real-time rotation speed of the rotary kiln, so that the laser pulse corresponds one-to-one with the sampling point on the surface of the cylinder.

[0027] Preferred solution: The edge extraction algorithm executed by the image processing and deformation resolution unit includes, in sequence: Noise filtering, threshold segmentation, mathematical morphology refinement and concatenation, and temporal coding storage.

[0028] Preferred solution: The calibrated world coordinate system is established in the following way: At least six non-coplanar feature points are arranged around the kiln body using standard calibration objects of known size. The camera's intrinsic and extrinsic parameters are calculated using feature point images acquired by CCD to achieve millimeter-level precision coordinate mapping.

[0029] Preferred solution: The alarm output interface outputs deformation reports at a cycle of ≤1 minute and supports trend curve display and predictive maintenance prompts.

[0030] A non-contact deformation monitoring method for rotary kilns includes the following steps: S1. Initialization steps: Set the measurement frequency, pulse laser wavelength, pulse width, emission angle, and edge extraction threshold according to the rotary kiln's operating status. S2. Contour acquisition steps: S201. Irradiate the rotating kiln cylinder in operation with a time-domain encoded pulsed laser beam at a low swoop angle; S202. Use a prism-cylindrical lens group to reflect and refract the light reflected from the surface of the cylinder multiple times to enhance the light intensity of the edge contour. S203. Synchronously acquire enhanced contour images using a CCD; S3. Image processing steps: Perform edge extraction on the contour image and reconstruct the current cylinder contour model; S4. Deformation calculation steps: Compare the current cylinder profile model with the pre-stored standard profile model in the calibrated world coordinate system, and calculate the radial and / or axial deformation. S5. Alarm procedure: If the deformation exceeds the set safety threshold, an alarm signal is issued. All of the above steps are completed non-contactly while the rotary kiln is operating at high temperature.

[0031] Preferred solution: In step S1, the measurement frequency is adjusted in real time according to the rotation speed of the rotary kiln, so that the angle between sampling points on the same circumference of the cylinder surface is ≤0.5°.

[0032] Preferred solution: In step S3, the edge extraction sequentially includes: Gaussian filtering for noise reduction, adaptive threshold segmentation, morphological thinning and breakpoint connection to obtain single-pixel continuous edges.

[0033] Preferred solution: In step S4, the calibrated world coordinate system is calibrated by setting up calibration objects with known three-dimensional coordinates on site and using a CCD imaging model to calibrate the camera's intrinsic and extrinsic parameters, with a calibration error ≤ 0.5 mm.

[0034] Preferred solution: After step S5, the following is also included: S6. Store the deformation amounts of each time in a time series, generate a creep trend curve, and issue a failure warning in advance when the deformation rate suddenly increases.

[0035] This project adopts an independent observation architecture design, with no physical connection between the entire system and the kiln body, completely avoiding the impact of high temperature and vibration on the sensors; in addition, it is designed to monitor small deformations in the early stage of material creep, supporting long-term tracking of slow deformations at the mm level, enabling prediction before failure, and improving safety and service life.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications made based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A non-contact deformation monitoring system for rotary kilns, characterized in that: include: A pulsed laser emitting module is used to irradiate the operating rotary kiln shell with a time-domain encoded pulsed laser beam at a low swoop angle. The optical edge enhancement module includes a prism-cylindrical lens group, which reflects and refracts the original contour light formed by the pulsed laser beam on the surface of the cylinder multiple times to enhance the light intensity distribution at the edge of the cylinder. The CCD synchronous acquisition module is used to receive the contour light signal processed by the optical edge enhancement module and output a digital image. The image processing and deformation calculation unit is connected to the CCD synchronous acquisition module. It is used to perform edge extraction and reconstruction of the current contour model on the digital image, and compare the current contour model with the pre-stored standard contour model through the calibrated world coordinate system to obtain the radial and / or axial deformation of the cylinder. An alarm output interface is used to issue an alarm signal when the deformation exceeds a set safety threshold. The pulsed laser emission module, optical edge enhancement module, and CCD synchronous acquisition module have no mechanical contact with the rotary kiln body.

2. The rotary kiln non-contact deformation monitoring system according to claim 1, characterized in that: The pulsed laser emitting module further includes: A frequency encoder is used to adaptively adjust the pulse repetition frequency according to the real-time rotation speed of the rotary kiln, so that the laser pulse corresponds one-to-one with the sampling point on the surface of the cylinder.

3. The rotary kiln non-contact deformation monitoring system according to claim 1, characterized in that: The edge extraction algorithm executed by the image processing and deformation solving unit includes, in sequence: Noise filtering, threshold segmentation, mathematical morphology refinement and concatenation, and temporal coding storage.

4. The rotary kiln non-contact deformation monitoring system according to claim 1, characterized in that: The calibrated world coordinate system is established in the following way: At least six non-coplanar feature points are arranged around the kiln body using standard calibration objects of known size. The camera's intrinsic and extrinsic parameters are calculated using feature point images acquired by CCD to achieve millimeter-level precision coordinate mapping.

5. The rotary kiln non-contact deformation monitoring system according to claim 1, characterized in that: The alarm output interface outputs deformation reports at a cycle of ≤1 minute and supports trend curve display and predictive maintenance prompts.

6. A non-contact deformation monitoring method for rotary kilns, comprising the following steps: S1. Initialization steps: Set the measurement frequency, pulse laser wavelength, pulse width, emission angle, and edge extraction threshold according to the rotary kiln's operating status. S2. Contour acquisition steps: S201. Irradiate the rotating kiln cylinder in operation with a time-domain encoded pulsed laser beam at a low swoop angle; S202. Use a prism-cylindrical lens group to reflect and refract the light reflected from the surface of the cylinder multiple times to enhance the light intensity of the edge contour. S203. Synchronously acquire enhanced contour images using a CCD; S3. Image processing steps: Perform edge extraction on the contour image and reconstruct the current cylinder contour model; S4. Deformation calculation steps: Compare the current cylinder profile model with the pre-stored standard profile model in the calibrated world coordinate system, and calculate the radial and / or axial deformation. S5. Alarm procedure: If the deformation exceeds the set safety threshold, an alarm signal is issued. All of the above steps are completed non-contactly while the rotary kiln is operating at high temperature.

7. The non-contact deformation monitoring method for rotary kilns according to claim 6, characterized in that: In step S1, the measurement frequency is adjusted in real time according to the rotation speed of the rotary kiln, so that the angle between sampling points on the same circumference of the cylinder surface is ≤0.5°.

8. A non-contact deformation monitoring method for a rotary kiln according to claim 6, characterized in that: in In step S3, the edge extraction sequentially includes: Gaussian filtering for noise reduction, adaptive threshold segmentation, morphological thinning, and breakpoint connection to obtain single-pixel continuous edges.

9. A non-contact deformation monitoring method for a rotary kiln according to claim 6, characterized in that: in In step S4, the calibrated world coordinate system is calibrated by setting up calibration objects with known three-dimensional coordinates on site and using a CCD imaging model to calibrate the camera's intrinsic and extrinsic parameters, with a calibration error ≤0.5mm.

10. A non-contact deformation monitoring method for a rotary kiln according to claim 6, characterized in that: in Step S5 is followed by: S6. Store the deformation amounts of each time in a time series, generate a creep trend curve, and issue a failure warning in advance when the deformation rate suddenly increases.

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