Device and method for detecting sealing gap of air preheater

Abstract

The invention discloses a device and a method for detecting a sealing gap of an air preheater. The device for detecting the sealing gap of the air preheater comprises an ultrasonic sensor, a signal processing unit and a communication unit. The ultrasonic generating end of the ultrasonic sensor is used for transmitting ultrasonic signals to the radial sealing piece and receiving echo signals. And the signal processing unit is used for calculating a real-time distance value according to the ultrasonic signal. And the communication unit is used for outputting the real-time distance value to an external system. The method for detecting the sealing gap of the air preheater comprises the following steps: S1, detecting the sealing gap of the air preheater through the device for detecting the sealing gap of the air preheater; and S2, comparing the real-time distance value with the target gap value, and outputting a comparison result. Compared with the prior art, the air preheater sealing gap detection device disclosed by the invention adopts non-contact measurement, avoids abrasion caused by contact, is simple and convenient to operate, realizes online accurate measurement, and reduces errors of manual measurement.

Description

Technical Field

[0001] This application relates to the field of rotary air preheaters for power plant boilers, and more specifically, to an air preheater sealing gap detection device and detection method. Background Technology

[0002] An air preheater is a heat exchange device that uses the heat from the flue gas at the boiler's tail end to heat the air needed for combustion. It is an important piece of equipment in large thermal power units. Because it operates in the area with the lowest flue gas temperature, it recovers the heat from the flue gas, reduces the exhaust gas temperature, and at the same time, the increased combustion air temperature is beneficial for fuel ignition and combustion, reducing losses from incomplete combustion.

[0003] Because of the gaps between the moving and stationary parts of the air preheater, and the pressure difference between the air and flue gas, leakage can occur. To prevent flue gas leakage into the primary and secondary air, an internal sealing system is installed. During each unit maintenance, the gaps at the moving and stationary joints of the sealing device need to be inspected and adjusted. Improper gap adjustment will increase air leakage, leading to a decrease in boiler economics. Furthermore, existing gap detection methods use plug gauges, which are difficult and inefficient due to the confined space and complex environment inside the equipment.

[0004] Therefore, how to improve the detection efficiency of the sealing gap of the air preheater has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to disclose an air preheater sealing gap detection device to improve the detection efficiency of air preheater sealing gap.

[0006] Another objective of this application is to disclose a method for detecting the sealing gap of an air preheater.

[0007] The first aspect of this application provides an air preheater sealing gap detection device. The air preheater includes a sector plate and a radial sealing plate, the surface of the sector plate facing the radial sealing plate is a first reference surface, the surface of the radial sealing plate facing the sector plate is a second reference surface, and the sealing gap of the air preheater is the gap between the first reference surface and the second reference surface;

[0008] The air preheater sealing gap detection device includes:

[0009] An ultrasonic sensor is disposed on the sector plate, and along the first direction, the distance between the ultrasonic generating end of the ultrasonic sensor and the first reference surface is n. The ultrasonic generating end is used to emit ultrasonic signals to the radial sealing sheet and receive echo signals. The first direction is the arrangement direction of the first reference surface and the second reference surface.

[0010] The signal processing unit is used to calculate the midpoint distance m between the ultrasonic generator end and the second reference surface based on the ultrasonic signal, and to calculate the real-time distance value between the first reference surface and the second reference surface based on mn.

[0011] A communication unit is used to output the real-time distance value to an external system.

[0012] In one possible implementation, the distance n between the ultrasonic wave generator and the first reference surface is zero.

[0013] In one possible implementation, multiple ultrasonic sensors are arranged along the radial direction of the air preheater.

[0014] In one possible implementation, an endoscope module is further included, which is detachably connected to the ultrasonic sensor and includes a camera and an antenna; the camera is used to capture images of the interior of the air preheater; and the antenna is used to transmit the images captured by the camera to an external system.

[0015] One possible implementation also includes an electromagnetic adsorption device for releasably fixing the ultrasonic sensor to the surface of the sector plate.

[0016] One possible implementation also includes a level for determining whether the ultrasonic sensor is in a horizontal or vertical state.

[0017] In one possible implementation, a power module is also included; the power module includes a battery, a power switch, and a charging interface; the battery is charged through the charging interface.

[0018] The air preheater sealing gap detection device disclosed in this application operates by first installing it on the side of the fan-shaped plate of the air preheater. The distance between the ultrasonic transmitter of the ultrasonic sensor and the surface of the fan-shaped plate facing the radial sealing sheet is determined, and the value of 'n' is input to the signal processing unit. The ultrasonic sensor emits an ultrasonic signal towards the radial sealing sheet and receives the echo. The signal processing unit performs calculations based on the ultrasonic signal to obtain the distance between the ultrasonic transmitter and the surface of the radial sealing sheet facing the fan-shaped plate, i.e., the intermediate distance 'm'. The real-time distance between the fan-shaped plate and the radial sealing sheet is calculated based on 'mn'. The communication unit outputs the obtained real-time distance value to an external system, thus completing the air preheater sealing gap detection. The operator can compare the real-time distance value with the target gap value and adjust the relative position of the fan-shaped plate and the radial sealing sheet according to the comparison result, so that the gap value between the radial sealing sheet and the fan-shaped plate approaches the target gap value.

[0019] Compared to related technologies, the air preheater sealing gap detection device disclosed in this application adopts non-contact measurement, avoiding wear caused by contact, simplifying operation, achieving accurate online measurement, and reducing errors from manual measurement. It provides reliable data support for subsequent sealing gap adjustment, which is beneficial for continuously controlling the air preheater's leakage rate at an optimal level and can significantly reduce energy consumption.

[0020] The second aspect of this application provides a method for detecting the sealing gap of an air preheater, comprising the following steps:

[0021] S1: The sealing gap of the air preheater is detected in a non-contact manner using a gap detection device; the gap detection device is the air preheater sealing gap detection device as described in any one of claims 1-7;

[0022] S2: Compare the real-time distance value with the target gap value and output the comparison result.

[0023] In one possible implementation, the comparison result is output in at least one of the following ways:

[0024] The difference between the real-time distance value and the target gap value is displayed on the display device;

[0025] The difference between the real-time distance value and the target gap value is sent to the user's terminal device;

[0026] When the difference between the real-time distance value and the target gap value exceeds a preset value, an alarm is triggered by the alarm device.

[0027] One possible implementation also includes step S3:

[0028] The air preheater is rotated, and the rotation angle of the air preheater is detected by a position detection device.

[0029] Based on the rotation angle, the measured real-time distance value is associated with the corresponding radial sealing sheet;

[0030] Steps S1 and S2 are repeated for the radial sealing sheet that passes through the measurement area in sequence.

[0031] The air preheater sealing gap detection method provided in this application, since it adopts the above-mentioned air preheater sealing gap detection device, has all the technical effects of the above-mentioned air preheater sealing gap detection device, which will not be repeated here. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the first air preheater sealing gap detection device disclosed in the embodiments of this application;

[0034] Figure 2 This is an exploded view of the first air preheater sealing gap detection device disclosed in the embodiments of this application;

[0035] Figure 3 This is a schematic diagram of the operation of the air preheater sealing gap detection device disclosed in the embodiments of this application;

[0036] Figure 4 for Figure 3 A magnified view of a section at point A in the middle;

[0037] Figure 5 This is a schematic diagram of the structure of the second air preheater sealing gap detection device disclosed in the embodiments of this application. Figure 1 ;

[0038] Figure 6 This is a schematic diagram of the structure of the second air preheater sealing gap detection device disclosed in the embodiments of this application. Figure 2 ;

[0039] Figure 7 This is a schematic diagram of the structure of the third air preheater sealing gap detection device disclosed in the embodiments of this application.

[0040] The attached figures are labeled as follows:

[0041] 10. Air preheater sealing gap detection device; 20. Sector plate; 30. Target; 40. Radial sealing plate; 50. Radial partition;

[0042] 100. Ultrasonic sensor; 200. Communication unit; 300. Electromagnetic adsorption device; 400. Power module; 410. Power switch; 420. Charging interface; 430. Battery; 500. Level; 510. Vertical level; 520. Horizontal level; 600. Indicator module; 700. Endoscope module; 710. Camera; 720. Antenna; 730. Connecting bracket; 800. Display device. Detailed Implementation

[0043] The purpose of this application is to disclose an air preheater sealing gap detection device to improve the detection efficiency of air preheater sealing gap.

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] The air preheater includes a sector plate 20, a radial baffle 50, and a radial sealing plate 40. During operation, the radial baffle 50 rotates around an axis, with the sector plate 20 positioned at both ends of the radial baffle 50 and perpendicular to the axis. The radial sealing plate 40 is mounted on the radial baffle 50 and rotates with it, positioned between the sector plate 20 and the radial baffle 50 to seal the gap between them. The surface of the sector plate 20 facing the radial sealing plate 40 is a first reference surface, and the surface of the radial sealing plate 40 facing the sector plate 20 is a second reference surface. The sealing gap of the air preheater is the gap between the first and second reference surfaces.

[0046] See Figures 1 to 7 The air preheater sealing gap detection device 10 disclosed in this application includes an ultrasonic sensor 100, a signal processing unit, and a communication unit 200.

[0047] The ultrasonic sensor 100 can be an industrial-grade high-frequency ultrasonic sensor, arranged on the radial side of the fan-shaped plate 20 of the air preheater, directly opposite the radial sealing plate 40. Along a first direction, the distance n between the ultrasonic generating end of the ultrasonic sensor 100 and the first reference surface is [value missing]. Here, the first direction refers to the arrangement direction of the first and second reference surfaces. The value of n reflects the installation position of the ultrasonic sensor 100. Due to the small sealing gap, to avoid interference, the ultrasonic generating end is installed on the upper side of the first reference surface. The ultrasonic generating end is used to transmit ultrasonic signals to the radial sealing plate 40 and receive echo signals.

[0048] The signal processing unit is communicatively connected to the ultrasonic sensor 100. It includes a microprocessor for calculating the intermediate distance *m* between the ultrasonic generator and the second reference plane based on the ultrasonic signal, and for calculating the real-time distance values ​​between the first and second reference planes based on *m*. The communication unit 200 can use a cable for wired communication or a signal transmitting antenna for wireless communication, for outputting the real-time distance values ​​to an external system.

[0049] During the operation of the air preheater sealing gap detection device 10 disclosed in this application, an ultrasonic sensor 100 is first installed on the side of the fan-shaped plate 20 of the air preheater. The distance between the ultrasonic generating end of the ultrasonic sensor 100 and the surface of the fan-shaped plate 20 facing the radial sealing plate 40 is determined, and the value n is input to the signal processing unit. The ultrasonic sensor 100 emits ultrasonic signals to the radial sealing plate 40 and receives the echoes. The signal processing unit performs calculations based on the ultrasonic signals to obtain the distance between the ultrasonic generating end and the surface of the radial sealing plate 40 facing the fan-shaped plate 20, i.e., the intermediate distance m. The real-time distance between the fan-shaped plate 20 and the radial sealing plate 40 is calculated based on mn. The communication unit 200 outputs the obtained real-time distance value to an external system, thus completing the air preheater sealing gap detection work. The operator can compare the real-time distance value with the target gap value and adjust the relative position of the fan-shaped plate 20 and the radial sealing plate 40 according to the comparison result so that the gap value between the radial sealing plate 40 and the fan-shaped plate 20 approaches the target gap value.

[0050] Compared to related technologies, the air preheater sealing gap detection device 10 disclosed in this application adopts non-contact measurement, avoiding wear caused by contact, simplifying operation, achieving accurate online measurement, and reducing errors from manual measurement. It provides reliable data support for subsequent sealing gap adjustment, which is beneficial for continuously controlling the air preheater's leakage rate at an optimal level, significantly reducing energy consumption and improving boiler thermal efficiency.

[0051] To simplify operation, the distance n between the ultrasonic generator and the first reference surface can be zero. When installing the ultrasonic sensor 100, the ultrasonic generator is aligned with the surface of the sector plate 20 facing the radial sealing plate 40, making n zero. The air preheater sealing gap detection device 10 of this design obtains the midpoint distance m between the ultrasonic generator and the surface of the radial sealing plate 40 facing the sector plate 20, which is the real-time distance between the sector plate 20 and the radial sealing plate 40. This eliminates the need for mn calculation, reduces accumulated errors introduced by multiple parameters, and makes the measurement results more direct and reliable. Furthermore, this design allows the sound wave to directly enter the measurement area after leaving the sensor, with its sole target being the radial sealing plate in front. This avoids interference from any unevenness on the surface of the sector plate 20, ensuring a clear echo signal and improving the accuracy of the measurement results.

[0052] To measure real-time distance values ​​at different radii of the air preheater, multiple air preheater sealing gap detection devices 10 can be arranged along the radial direction of the air preheater. For example... Figure 3As shown, five ultrasonic sensors 100 are arranged at intervals along the radial direction of the sector plate 20. The deformation of the radial partition 50 due to the temperature gradient causes the real-time distance between the radial sealing plate 40 and the sector plate 20 to differ at different radii. This arrangement can simultaneously monitor the real-time distance of the radial sealing plate 40 at different radii, thereby effectively capturing radial deformation and ensuring that the adjustment decision is based on global optimum, providing a comprehensive data foundation for subsequent precise adjustment.

[0053] To observe the internal condition of the air preheater, the air preheater sealing gap detection device 10 may further include an endoscope module 700, which is detachably connected to the ultrasonic sensor 100. Figure 1 and Figure 7 As can be seen, the endoscope module 700 can be connected to the ultrasonic sensor 100 via a connecting bracket 730. The connecting bracket 730 and the housing of the ultrasonic sensor 100 are hinged to a hinge axis, allowing the connecting bracket 730 and the endoscope module 700 mounted thereon to rotate around the hinge axis, thereby adjusting the imaging angle of the endoscope module 700. The endoscope module 700 includes a camera 710 and an antenna 720. The camera 710 is used to capture images of the interior of the air preheater, allowing observation of whether the radial sealing plate 40 is severely worn, whether the fan-shaped plate 20 is covered with dust and scale, and whether foreign objects are stuck in the sealing gap. The endoscope module 700 can integrate an illumination lamp for normal operation in the dark. The antenna 720 is used to transmit the images captured by the camera 710 to an external system. The signal can be transmitted wirelessly via WIFI, amplified by a relay, and received by a computer or mobile phone near the air preheater equipment for real-time observation of its internal conditions. The air preheater sealing gap detection device 10 designed here has visual verification and diagnostic functions. Combined with the sealing gap detection results, operators can develop more targeted maintenance plans and shorten maintenance time.

[0054] To facilitate the installation of the air preheater sealing gap detection device 10, an electromagnetic adsorption device 300 can be installed on the ultrasonic sensor 100 to releasably fix the ultrasonic sensor 100 to the surface of the sector plate 20. (See [reference]). Figure 5 and Figure 6The electromagnetic adsorption device 300 may include a high-strength electromagnetic chuck and an electromagnetic switch. When installing the air preheater sealing gap detection device 10, the device assembly is placed at the predetermined measurement point. Holding the device, the working surface of the electromagnetic chuck is pressed tightly against the surface of the sector plate 20. The electromagnetic switch is turned on, energizing the electromagnet, which generates a strong magnetic force, firmly fixing the entire device to the sector plate 20, thus achieving non-invasive installation. When disassembly is required, simply disconnecting the electromagnet power supply via the electromagnetic switch causes the magnetic force to disappear instantly, allowing the entire device to be safely removed. The process is simple and quick. No welding, drilling, or tapping is required on the sector plate 20, avoiding potential damage, thermal stress deformation, or material changes to the sector plate 20's structure during installation, thus maintaining the integrity of the original equipment. This design also facilitates adjustment or rearrangement of the measurement point positions, providing high flexibility.

[0055] To improve the accuracy of the measurement data from the ultrasonic sensor 100, the air preheater sealing gap detection device 10 also includes a level 500. The level 500 may include a vertical bubble 510 and a horizontal bubble 520. Small, high-precision bubble levels can be directly embedded or fixed to the surface of the housing of the air preheater sealing gap detection device 10. By observing the level 500, it can be determined whether the ultrasonic sensor 100 is in a horizontal or vertical position. Ideally, ultrasonic ranging requires the sound wave propagation direction to be perpendicular to the measuring surface. The air preheater sealing gap detection device 10 integrates the level 500 and performs on-site leveling, directly eliminating measurement errors caused by tilt angles during installation and ensuring the accuracy of the measurement data.

[0056] To improve the flexibility and portability of the device, the air preheater sealing gap detection device 10 also includes a power module 400. The power module 400 includes a battery 430, a power switch 410, and a charging interface 420. The battery 430 can be a high-energy-density rechargeable lithium battery to power the ultrasonic sensor 100, electromagnetic adsorption device 300, and other components. The battery 430 is equipped with a corresponding charging management circuit and is charged through the charging interface 420. The power module 400, ultrasonic sensor 100, signal processing unit, and communication unit 200 can be integrated into a single housing to form a unified, independent detection device. The power switch 410 is located on the housing for manual power control. This design eliminates the need for power cables and, combined with wireless communication, enables convenient installation even in complex environments where wiring is difficult, significantly reducing installation costs and complexity.

[0057] Based on the above structure, in order to facilitate maintenance and charging, the air preheater sealing gap detection device 10 may also be equipped with an indicator module 600. The indicator module 600 may include a battery low voltage indicator and a charging indicator to clearly indicate the power status and arrange charging or replacement before the power is exhausted.

[0058] Another objective of this application is to disclose a method for detecting the sealing gap of an air preheater, which includes steps S1 and S2. Step S1 includes detecting the sealing gap of the air preheater in a non-contact manner using a gap detection device. The gap detection device is the air preheater sealing gap detection device 10 described in any of the possible implementations above. Step S2 includes comparing the real-time distance value obtained in step S1 with a target gap value and outputting the comparison result. The air preheater sealing gap detection method provided in this application, due to the use of the aforementioned air preheater sealing gap detection device 10, possesses all the technical effects of the aforementioned air preheater sealing gap detection device 10, which will not be elaborated upon here.

[0059] To make the test results more reliable, a target 30 can be installed on the radial sealing plate 40, see [link / reference]. Figure 4 The target 30 is a plate-shaped component bent at a right angle. One side of it is magnetically attached to the radial sealing plate 40, so that the upper surface of the target 30 and the upper surface of the radial sealing plate 40 are on the same plane, and the ultrasonic wave generating end is directly facing the target 30. A target 30 is arranged corresponding to the detection position of each air preheater sealing gap detection device 10. The original radial sealing plate 40, with its edge serving as the ultrasonic wave reflecting surface, has a small effective reflecting area and is prone to becoming irregular due to wear, leading to scattering and diffraction of the ultrasonic wave signal, resulting in a weak and unstable echo signal. The target 30 of this design provides a larger and flatter reflecting plane, greatly reducing the probability of false detection and signal loss, and improving measurement accuracy and reliability.

[0060] In one specific embodiment, the comparison result is output in at least one of the following ways: displaying the difference between the real-time distance value and the target gap value through the display device 800; sending the difference between the real-time distance value and the target gap value to the user's terminal device; and issuing an alarm through the alarm device when the difference between the real-time distance value and the target gap value exceeds a preset value.

[0061] The display device 800 can be a digital display screen integrated into the air preheater sealing gap detection device 10, using a low-power, high-brightness segment LCD or OLED (Organic Light Emitting Diode) screen. This design eliminates the need for external equipment; the display device 800 allows immediate confirmation of whether the air preheater sealing gap detection device 10 is functioning correctly and whether the real-time distance value is within a reasonable range.

[0062] The difference between the real-time distance value and the target gap value is sent to the user's terminal device, such as a computer or handheld terminal. This design, along with the installed dedicated software, not only displays the measurement data in real time on the interface but also automatically stores the data for subsequent analysis and diagnosis.

[0063] When the difference between the real-time distance value and the target gap value exceeds a preset value, an alarm is triggered. The alarm device can be an audible alarm, a visual alarm, or a combination of both. Proactively alerting operators when abnormal values ​​occur significantly reduces their workload.

[0064] To achieve continuous monitoring, the air preheater sealing gap detection method further includes step S3: rotating the air preheater and detecting the rotation angle of the air preheater through a position detection device; associating the measured real-time distance value with the corresponding radial sealing plate 40 based on the rotation angle; and repeating steps S1 and S2 for the radial sealing plates 40 that pass through the measurement area in sequence.

[0065] The position detection device sends the real-time angular position signal of the air preheater shaft to the terminal device. Each radial sealing plate 40 is numbered and corresponds one-to-one with a set angular position. The terminal device uses the position signal to bind the real-time distance value reported by the air preheater sealing gap detection device 10 to a specific radial sealing plate 40 and stores it.

[0066] During the testing process, after measuring and possibly adjusting the first radial sealing plate 40, the air preheater is continuously rotated. When the position detection device detects that the shaft has rotated past a predetermined angle and the next radial sealing plate 40 has entered the measurement area, steps S1 and S2 are repeated to detect the gap of that radial sealing plate 40. This process is repeated continuously to achieve continuous and cyclical detection and adjustment of all radial sealing plates 40. This design, through the cooperation of the position detection device and the gap detection device, can identify and track each radial sealing plate 40, achieving continuous monitoring of the gap across the entire air preheater and avoiding monitoring blind spots.

[0067] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may include steps or units not listed, but rather steps or units not listed. Additionally, in the description of embodiments in this application, "a plurality of" means two or more.

[0068] In the description of this application, it should be understood that the terms "height," "thickness," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, "a plurality of" means two or more, and "at least one" can mean one, two, or more, unless otherwise expressly specified.

[0069] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Specific technical means in some embodiments may be incorporated, in whole or in part, into another embodiment unless explicitly excluded by another embodiment. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for detecting the sealing gap of an air preheater, characterized in that, The air preheater includes a fan-shaped plate (20) and a radial sealing plate (40). The surface of the fan-shaped plate (20) facing the radial sealing plate (40) is a first reference surface, and the surface of the radial sealing plate (40) facing the fan-shaped plate (20) is a second reference surface. The sealing gap of the air preheater is the gap between the first reference surface and the second reference surface. The air preheater sealing gap detection device (10) includes: An ultrasonic sensor (100) is disposed on the sector plate (20), and along the first direction, the distance between the ultrasonic generating end of the ultrasonic sensor (100) and the first reference surface is n. The ultrasonic generating end is used to emit ultrasonic signals to the radial sealing sheet (40) and receive echo signals. The first direction is the arrangement direction of the first reference surface and the second reference surface. The signal processing unit is used to calculate the midpoint distance m between the ultrasonic generator end and the second reference surface based on the ultrasonic signal, and to calculate the real-time distance value between the first reference surface and the second reference surface based on mn. The communication unit (200) is used to output the real-time distance value to an external system.

2. The air preheater sealing gap detection device as described in claim 1, characterized in that, The distance n between the ultrasonic wave generator and the first reference surface is zero.

3. The air preheater sealing gap detection device as described in claim 1, characterized in that, Multiple ultrasonic sensors (100) are arranged along the radial direction of the air preheater.

4. The air preheater sealing gap detection device as described in claim 1, characterized in that, It also includes an endoscope module (700), which is detachably connected to the ultrasonic sensor (100) and includes a camera (710) and an antenna (720); the camera (710) is used to capture images of the interior of the air preheater; the antenna (720) is used to transmit the images captured by the camera (710) to an external system.

5. The air preheater sealing gap detection device as described in claim 1, characterized in that, It also includes an electromagnetic adsorption device (300) for releasably fixing the ultrasonic sensor (100) to the surface of the sector plate (20).

6. The air preheater sealing gap detection device as described in claim 1, characterized in that, It also includes a level (500) for determining whether the ultrasonic sensor (100) is in a horizontal or vertical state.

7. The air preheater sealing gap detection device as described in claim 1, characterized in that, It also includes a power module (400); the power module (400) includes a battery (430), a power switch (410) and a charging interface (420); the battery (430) is charged through the charging interface (420).

8. A method for detecting the sealing gap of an air preheater, characterized in that, Includes the following steps: S1: The sealing gap of the air preheater is detected in a non-contact manner by means of a gap detection device; the gap detection device is the air preheater sealing gap detection device (10) as described in any one of claims 1-7. S2: Compare the real-time distance value with the target gap value and output the comparison result.

9. The method for detecting the sealing gap of an air preheater as described in claim 8, characterized in that, The comparison result is output in at least one of the following ways: The difference between the real-time distance value and the target gap value is displayed by the display device (800); The difference between the real-time distance value and the target gap value is sent to the user's terminal device; When the difference between the real-time distance value and the target gap value exceeds a preset value, an alarm is triggered by the alarm device.

10. The method for detecting the sealing gap of an air preheater as described in claim 8, characterized in that, It also includes step S3: The air preheater is rotated, and the rotation angle of the air preheater is detected by a position detection device. Based on the rotation angle, the measured real-time distance value is associated with the corresponding radial sealing sheet; Steps S1 and S2 are repeated for the radial sealing sheet (40) that passes through the measurement area in sequence.

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