Method for measuring the adhesion of a slag scraping grid blade to a filter grid

Abstract

The application relates to a method for measuring the adhesion of a slag scraping type grid scraper and a filter grid, and relates to the field of sewage treatment. The technical scheme adopts a flexible detection structure of an array of resistance strain gauges and a double-layer PET interlayer, can be directly laid on the surface of an assembled grid, and is suitable for different types of slag scraping type grids of different specifications. The double-layer PET structure ensures that the detection surfaces of the strain gauges are coplanar and the stress conditions are consistent. An RC frequency selection circuit and a single-channel acquisition scheme combining multi-frequency hybrid excitation are adopted, different harmonic frequencies are used to distinguish the strain signals, and only one bus is needed to realize synchronous acquisition of multiple channels, so that the wiring structure is greatly simplified. Dynamic and continuous detection can be realized along with the movement of the scraper, complete full-section adhesion distribution data can be obtained in one cycle of the scraper, and the detection efficiency is much higher than that of the traditional manual plug gauge point-by-point measurement mode. The detection result is quantitatively output in the form of an electric signal, and the detection consistency and accuracy are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method for determining the fit between the scraper of a scraper-type bar screen and the filter screen. Background Technology

[0002] As a crucial solid-liquid separation component in wastewater treatment processes, the fit between the scraper and the filter screen directly determines the scraping efficiency and water flow performance of the scraper-type bar screen. Currently, the industry commonly uses laser ranging to statically inspect unassembled, independent screens for bar screen flatness testing. However, for assembled bar screen equipment, the fit between the scraper and the screen is primarily determined by operators using feeler gauges for manual multi-point measurements.

[0003] Specifically, the aforementioned laser inspection method can only perform flatness testing on the grid plates individually before grid assembly. After the grid is assembled as a whole, components such as the scraper, transmission chain, and frame obstruct the laser beam path, making it impossible to perform dynamic fit testing while the scraper is in motion. Manual feeler gauge inspection is cumbersome and inefficient, with results heavily influenced by the operator's experience and technique, making consistency and accuracy difficult to guarantee. Furthermore, it cannot achieve long-term continuous online monitoring. Therefore, the market currently lacks a dedicated testing solution specifically for the fit between the grid plates and scraper of scraper-type grids. Summary of the Invention

[0004] The purpose of this invention is to provide a method for determining the fit between the scraper of a slag-scraping type grid and the filter grid plate, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for determining the adhesion between a scraper-type grid scraper and a filter grid plate is disclosed. The method employs a system for determining the adhesion between the scraper-type grid scraper and the filter grid plate. The system includes a lower PET support layer, multiple resistance strain gauges arranged in an array on the lower PET support layer, an upper PET protective layer covering the resistance strain gauges, multiple RC frequency selective circuits connected to each resistance strain gauge, a hybrid multi-frequency excitation input bus, a grounding and signal output bus, a multi-frequency hybrid excitation unit, a single-channel data acquisition module, and a filtering unit. Each RC frequency selective circuit has a different resonant frequency. The hybrid multi-frequency excitation input bus is connected to the input terminal of each RC frequency selective circuit. The grounding and signal output bus is connected to the output terminal of each resistance strain gauge. The output terminal of the multi-frequency hybrid excitation unit is connected to the hybrid multi-frequency excitation input bus. The input terminal of the single-channel data acquisition module is connected to the grounding and signal output bus. The input terminal of the filtering unit is connected to the output terminal of the single-channel data acquisition module. The determination method includes the following steps: The measuring system is arranged between the grid plate and the scraper of the scraper-type grid, and the measuring system is fixed to prevent it from being displaced as the scraper moves. The measurement system was calibrated under no-load conditions, and the signal baselines corresponding to each resistance strain gauge were collected and adjusted to zero. The multi-frequency hybrid excitation unit is activated, and a hybrid AC excitation voltage containing multiple different frequency components is input to each of the RC frequency selection circuits through the hybrid multi-frequency excitation input bus; Each of the RC frequency selection circuits selects the excitation voltage component corresponding to its resonant frequency, so that each resistance strain gauge is activated only under the excitation voltage of its corresponding frequency. The drive scraper moves along the surface of the grid plate. When the scraper passes each of the resistance strain gauges, it applies pressure to the upper PET protective layer, causing the resistance strain gauges to deform and output a strain signal carrying the corresponding frequency carrier. All strain signals output by the resistance strain gauges are mixed and collected through the grounding and signal output bus, and then acquired by the single-channel data acquisition module. The filtering unit splits the mixed signal by frequency and extracts the strain signal corresponding to each frequency component. Based on the intensity of each extracted strain signal, the combined force between the scraper and the grid plate at the corresponding position is calculated, and the fit between the scraper and the grid plate is judged by comparing the combined forces at different positions.

[0006] In some embodiments, the plurality of resistance strain gauges are full-bridge resistance strain gauges, and the plurality of resistance strain gauges are arranged in a matrix array with multiple rows and columns on the lower PET support layer, with the column direction of the array being consistent with the direction of travel of the scraper.

[0007] In some embodiments, each of the RC frequency selection circuits includes a surface-mount capacitor and a surface-mount resistor, and the resonant frequencies of each RC frequency selection circuit are set to increase sequentially in the order of 1kHz, 2kHz, 3kHz... with a frequency interval of 1kHz between adjacent frequency points; The strain gauge and the chip capacitor and chip resistor in the RC frequency selective circuit are fixed to the lower PET support layer by surface mounting, and are sandwiched and covered by the upper PET protective layer and the lower PET support layer to form a sandwich structure.

[0008] In some embodiments, the resistance strain gauge is made by directly printing the resistance material onto the inner layer of a PET substrate using an FPC embedded resistor method, and then covered by the upper PET protective layer and the lower PET support layer to form an integrated sandwich structure.

[0009] In some embodiments, the step of performing no-load calibration on the measurement system, acquiring the signal baseline corresponding to each of the resistance strain gauges, and adjusting it to zero specifically includes: Keep the upper PET protective layer and the lower PET support layer in an unloaded state without external pressure; The output signal of each RC frequency selection circuit at its corresponding resonant frequency point is collected as a baseline value. The baseline values ​​of each frequency point are uniformly adjusted to the zero-point reference to eliminate the effects of initial deformation and circuit offset.

[0010] In some embodiments, the step of selecting the excitation voltage component corresponding to its resonant frequency by each of the RC frequency selective circuits, so that each strain gauge is activated only under the excitation voltage at its corresponding frequency, specifically includes: The 1kHz frequency component passes only through the RC frequency selection circuit with a resonant frequency of 1kHz, activating the corresponding first resistance strain gauge and generating a strain signal with a 1kHz carrier wave. The 2kHz frequency component passes only through the RC frequency selection circuit with a resonant frequency of 2kHz, activating the corresponding second resistance strain gauge and generating a strain signal with a 2kHz carrier wave. Similarly, each of the resistance strain gauges generates a strain signal only under the excitation voltage at its corresponding resonant frequency, and the other frequency components are filtered out by the corresponding RC frequency selection circuit.

[0011] In some embodiments, the filtering unit includes a multi-bandpass filter, wherein the passband center frequency of each bandpass filter corresponds to the resonant frequency of one of the RC frequency selection circuits; the step of splitting the mixed signal by frequency through the filtering unit and extracting the strain signal corresponding to each frequency component specifically includes: Each bandpass filter removes other frequency components from the mixed signal, retaining only the strain signal at the corresponding frequency; The strain signal change curves extracted by each bandpass filter are output separately to synchronously acquire the dynamic strain data of all the resistance strain gauges.

[0012] In some implementations, the multi-frequency hybrid excitation unit adopts a working mode of simultaneously outputting a hybrid AC excitation voltage with multiple frequencies superimposed, or adopts a working mode of rapidly switching frequency output; The measurement system also includes a host computer, which is connected to the output of the filtering unit. The determination method further includes: The strain signals of each frequency component extracted are transmitted to the host computer; The host computer draws a point cloud diagram of the force changes at each position during the scraper's movement based on the correspondence between each frequency component and the physical position of the resistance strain gauge. When the fit at any position is detected to be lower than the preset standard, the host computer outputs an alarm signal.

[0013] In some embodiments, the step of calculating the combined force between the scraper and the grid plate at corresponding positions based on the intensity of each extracted strain signal, and determining the adhesion between the scraper and the grid plate by comparing the combined forces at different positions, specifically includes: Based on the relationship that the deformation of a resistance strain gauge is proportional to the change in resistance value, the current value of the strain signal is converted into the combined force between the scraper and the grid plate at the corresponding position. The combined force includes the resultant force of pressure, friction and shear. The combined force values ​​collected by the resistance strain gauges at different locations are compared laterally. The location where the deviation of the combined force value exceeds the preset threshold is determined to be the location of abnormal adhesion between the scraper and the grid plate.

[0014] In some embodiments, in the step of arranging the measuring system between the grid plate and the scraper of the scraper-type grid, the measuring system is detachably fixed to the surface of the grid plate in a short-term assembly manner, and the fit test is completed once the scraper runs for one cycle; or the measuring system is fixedly installed on the grid scraper and moves with the scraper for a long time to achieve real-time monitoring. The hybrid multi-frequency excitation input bus is arranged on one side of the lower PET support layer along the scraper travel direction, and the grounding and signal output bus is arranged on the other side of the lower PET support layer. The extension direction of both buses is consistent with the scraper travel direction.

[0015] The beneficial effects of the technical solution provided by this invention include at least the following: This technical solution employs a flexible detection structure combining a resistance strain gauge array with a double-layer PET interlayer. It can be directly laid on the surface of an assembled grid, adapting to various specifications of scraper-type grids. The double-layer PET structure ensures that the detection surfaces of each strain gauge are coplanar, guaranteeing consistent stress conditions throughout. A single-channel acquisition scheme combining an RC frequency selection circuit and multi-frequency hybrid excitation distinguishes different strain signals through different resonant frequencies. Only one bus is needed for synchronous acquisition of multiple data streams, significantly simplifying the wiring structure and effectively avoiding crosstalk and timing deviations between channels in multi-channel acquisition. Dynamic continuous detection is achieved as the scraper moves, acquiring complete full-section fit distribution data in one scraper cycle, resulting in significantly higher detection efficiency than traditional manual feeler gauge point-by-point measurement. The detection results are quantified and output as electrical signals, eliminating human error and greatly improving consistency and accuracy. It supports both short-term detachable assembly and long-term fixed installation modes, suitable for periodic inspections and maintenance, and can also be connected to a host computer to generate stress distribution point cloud maps for real-time online monitoring and anomaly alarms. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0017] Figure 1 A flowchart illustrating a method for determining the fit between a scraper and a filter screen according to an exemplary embodiment of the present invention is shown.

[0018] Figure 2 A schematic diagram of the structure of a system for measuring the fit between a scraper and a filter screen provided in an exemplary embodiment of the present invention is shown.

[0019] Figure 3 This diagram illustrates the connection between the resistance strain gauge, RC frequency selective circuit, upper PET protective layer, and lower PET support layer of a system for measuring the fit between a scraper and a filter grid provided in an exemplary embodiment of the present invention.

[0020] Figure 4 The diagram illustrates the connection between the resistance strain gauge, RC frequency selection circuit, hybrid multi-frequency excitation input bus, grounding and signal output bus, multi-frequency hybrid excitation unit, single-channel data acquisition module, filtering unit and host computer of the system for measuring the fit between the scraper and filter grid provided in an exemplary embodiment of the present invention.

[0021] In the diagram: 1. Resistance strain gauge; 2. RC frequency selection circuit; 3. Upper PET protective layer; 4. Lower PET support layer; 5. Hybrid multi-frequency excitation input bus; 6. Grounding and signal output bus. Detailed Implementation

[0022] 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.

[0023] In this specification, identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, while the terms "bottom surface," "top surface," "inner," and "outer" refer to directions towards or away from a specific component. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this specification, "multiple" means two or more.

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 2 This diagram illustrates a structural schematic of a system for measuring the fit between a scraper and a filter screen according to an exemplary embodiment of the present invention. Figure 3 This diagram illustrates the connection method between the resistance strain gauge, RC frequency selective circuit, upper PET protective layer, and lower PET support layer of the system for measuring the fit between the scraper and filter grid provided in an exemplary embodiment of the present invention. Figure 4 This diagram illustrates the connection between the resistance strain gauges, RC frequency selection circuits, hybrid multi-frequency excitation input bus, grounding and signal output bus, multi-frequency hybrid excitation unit, single-channel data acquisition module, filtering unit, and host computer of a system for measuring the adhesion between a scraper-type grid scraper and a filter grid provided in an exemplary embodiment of the present invention. The system mainly comprises two parts: a flexible detection body and peripheral circuit units. The flexible detection body includes a lower PET support layer 4, multiple resistance strain gauges 1, an upper PET protective layer 3, multiple RC frequency selection circuits 2, a hybrid multi-frequency excitation input bus 5, and a grounding and signal output bus 6. The peripheral circuit units include a multi-frequency hybrid excitation unit, a single-channel data acquisition module, a filtering unit, and a host computer.

[0026] It can be understood that a multi-frequency hybrid excitation unit refers to a functional circuit unit capable of generating and outputting a superimposed signal containing multiple sinusoidal AC voltage components of different frequencies, used to simultaneously provide the corresponding frequency excitation source to each RC frequency selection circuit via a bus. A filtering unit refers to a functional circuit unit containing multiple independent bandpass filters, capable of separating and extracting the frequency component signals corresponding to each resistance strain gauge from the hybrid strain signal according to frequency.

[0027] In some embodiments, see Figure 2 and Figure 3 The lower PET support layer 4 is made of rigid PET material, which has a certain structural rigidity to ensure the flatness of the detection plane, while retaining appropriate flexibility to adapt to the slight curvature of the grid surface. Multiple resistance strain gauges 1 are arranged in an array on the upper surface of the lower PET support layer 4.

[0028] In this embodiment, the resistance strain gauge 1 is a high-precision full-bridge resistance strain gauge with temperature self-compensation, high detection sensitivity, and good stability. The full-bridge structure can effectively offset temperature drift and lateral strain interference, resulting in a large output signal amplitude and excellent linearity. The resistance strain gauge 1 is arranged in a multi-row, multi-column matrix array on the lower PET support layer 4, for example, 4 rows and 7 columns, totaling 28 detection points. The column direction of the array is consistent with the scraper's traveling direction. Setting multiple columns of detection points along the scraper's traveling direction allows for the acquisition of force data at different times at the same longitudinal position during the scraper's movement, achieving dynamic continuous detection. Setting multiple rows of detection points laterally can cover different positions in the width direction of the scraper, comprehensively reflecting the fit distribution across the entire width range of the scraper.

[0029] In some embodiments, see Figure 2 and Figure 3 The upper PET protective layer 3 covers the multiple resistance strain gauges 1, forming a sandwich structure together with the lower PET support layer 4, clamping and fixing all the resistance strain gauges 1 and the RC frequency selection circuit 2 in the middle. The upper PET protective layer 3 provides physical protection for the internal resistance strain gauges 1 and circuit components, preventing the scraper from directly scratching and damaging the strain gauges and solder joints; on the other hand, the clamping effect of the upper and lower PET sheets ensures that the detection surfaces of all resistance strain gauges 1 are on the same plane, ensuring consistent stress conditions and avoiding detection errors caused by inconsistent strain gauge installation heights.

[0030] In some embodiments, see Figure 2 , Figure 3 and Figure 4 Each RC frequency selection circuit 2 is connected to a corresponding resistance strain gauge 1, and each RC frequency selection circuit 2 is set with a different resonant frequency. Each RC frequency selection circuit 2 includes a surface-mount capacitor and a surface-mount resistor, and the corresponding resonant frequency is set by adjusting the parameter values ​​of the capacitor and resistor.

[0031] In this embodiment, the resonant frequencies of each RC frequency selection circuit 2 are set in ascending order of 1kHz, 2kHz, 3kHz, etc., with a frequency interval of 1kHz between adjacent frequency points. The function of the RC frequency selection circuit 2 is to ensure that only AC excitation voltage with a frequency consistent with its resonant frequency can pass through the circuit and activate the corresponding resistance strain gauge 1, while excitation voltages of other frequencies are filtered out, thereby achieving frequency differentiation of multiple signals on a single bus.

[0032] In some embodiments, see Figure 2 , Figure 3 and Figure 4 A hybrid multi-frequency excitation input bus 5 is arranged along the scraper's travel direction on one side of the lower PET support layer 4, and is connected to the input terminals of each RC frequency selection circuit 2. It is used to uniformly input a hybrid AC excitation voltage containing multiple different frequency components to all RC frequency selection circuits 2. A grounding and signal output bus 6 is arranged on the other side of the lower PET support layer 4, and is connected to the output terminals of each resistance strain gauge 1. It is used to collect the strain signals output by all resistance strain gauges 1 and transmit them uniformly. The extension direction of both buses is consistent with the scraper's travel direction. This layout can shorten the routing distance from each RC frequency selection circuit 2 to the input bus, reducing the impact of parasitic parameters on the frequency selection characteristics.

[0033] In some embodiments, see Figure 2 , Figure 3 and Figure 4 The output of the multi-frequency hybrid excitation unit is connected to the hybrid multi-frequency excitation input bus 5, used to generate and output an AC excitation voltage containing multiple superimposed frequency components. The multi-frequency hybrid excitation unit can operate by simultaneously outputting a hybrid AC excitation voltage containing multiple superimposed frequencies, i.e., generating a mixed signal containing all target frequency components at once through a signal synthesis circuit; or it can operate by rapidly switching the frequency output, i.e., quickly switching the output between different frequencies at a high rate, effectively achieving simultaneous multi-frequency excitation by utilizing the time difference of mechanical response. The former has better signal quality and no switching noise, while the latter has a simpler circuit structure and lower cost; the choice can be made based on the actual application scenario.

[0034] In some embodiments, see Figure 2 , Figure 3 and Figure 4The input terminal of the single-channel data acquisition module is connected to the ground and signal output bus 6, and is used to acquire strain signals that are mixed with all frequency components. Traditional multi-channel strain detection schemes require configuring an independent data acquisition channel for each strain gauge, resulting in a large number of channels, complex wiring, high cost, and easy crosstalk between multiple channels. This invention adopts a single-channel data acquisition scheme, in which all strain signals are mixed and acquired on the same bus, which greatly simplifies the system structure and reduces hardware costs.

[0035] In some embodiments, see Figure 2 , Figure 3 and Figure 4 The input of the filtering unit is connected to the output of the single-channel data acquisition module. It is used to split the mixed strain signal according to frequency and extract the strain signal corresponding to each frequency component. The filtering unit contains multiple bandpass filters, each with a passband center frequency corresponding to the resonant frequency of an RC frequency selection circuit 2. Each bandpass filter filters out other frequency components from the mixed signal, retaining only the strain signal at the corresponding frequency. This re-splits the mixed multi-channel strain signal into independent signals, outputting the corresponding strain signal change curves, thus achieving synchronous acquisition of dynamic strain data from all resistance strain gauges 1.

[0036] In some embodiments, see Figure 2 , Figure 3 and Figure 4 The host computer is connected to the output of the filtering unit to receive the strain signals split by the filtering unit. Based on the one-to-one correspondence between each frequency component and the physical position of the resistance strain gauge 1, the signal data is mapped to the corresponding detection point, and a point cloud map of the force changes at each position during the scraper's movement is drawn, visually displaying the fit distribution of the entire grid surface. The host computer also has preset fit judgment standards. When the fit at any position is detected to be lower than the preset standard, the host computer outputs an alarm signal to remind maintenance personnel to make timely adjustments and maintenance.

[0037] In one example, the surface-mount capacitors and resistors in the resistance strain gauge 1 and the RC frequency selection circuit 2 are surface-mounted and soldered onto the lower PET support layer 4. After soldering, the upper PET protective layer 3 is then covered to form a sandwich structure. This process is mature, has high mounting accuracy, and allows for easy component replacement, making it suitable for small-batch customized production and applications where flexible adjustment of testing points is required.

[0038] In another example, the resistance strain gauge 1 uses an FPC embedded resistor method, directly printing the resistive material onto the inner layer of the PET substrate to form an embedded resistance strain structure, which is then covered by an upper PET protective layer 3 and a lower PET support layer 4 to form an integrated sandwich structure. The capacitors and resistors of the RC frequency selection circuit 2 can also be manufactured using either an embedded process or a surface mount process. The advantages of this integrated structure are a thinner overall thickness, higher surface flatness, no component detachment, and better reliability, making it suitable for applications requiring long-term fixed installation and continuous operation.

[0039] Figure 1 The flowchart illustrates a method for determining the adhesion between a scraper and a filter screen according to an exemplary embodiment of the present invention. The method for detecting the adhesion between the scraper and the filter screen using the aforementioned measurement system specifically includes the following steps: Step S1: The flexible detection body of the measurement system is laid flat on the surface of the scraper grid, between the grid and the scraper. The flexible detection body is fixed around its perimeter using tape or magnetic attraction to prevent it from shifting in the same direction as the scraper during the detection process, thus ensuring accurate detection position.

[0040] In some embodiments, depending on the usage scenario, the measurement system has two installation modes: In the short-term assembly mode, the measurement system is temporarily fixed to the surface of the grid plate in a detachable manner. The scraper can complete a full-section fit test in one complete cycle. After the test is completed, it can be removed. This mode is suitable for scenarios such as regular equipment inspection and factory inspection. In the long-term fixed mode, the measurement system is installed on the grid scraper in a fixed assembly manner. It moves with the scraper for a long time and is used in conjunction with the host computer to achieve real-time online monitoring. This mode is suitable for continuous monitoring scenarios under important working conditions.

[0041] Step S2: Keep the upper PET protective layer 3 and the lower PET support layer 4 in an unloaded state without external pressure, start the acquisition system, acquire the output signal of the corresponding resonant frequency point of each RC frequency selection circuit 2 as the baseline value, and then uniformly adjust the baseline value of each frequency point to the zero reference.

[0042] In this embodiment, step S2 is used to eliminate systematic errors such as initial deformation of PET sheet, inherent circuit offset, and zero drift, so as to ensure the accuracy of the test results.

[0043] Step S3: Start the multi-frequency hybrid excitation unit and input a hybrid AC excitation voltage containing multiple different frequency components to each RC frequency selection circuit 2 through the hybrid multi-frequency excitation input bus 5.

[0044] In step S4, each RC frequency selection circuit 2 selects the excitation voltage component corresponding to its resonant frequency, so that each resistance strain gauge 1 is activated only under the excitation voltage of its corresponding frequency.

[0045] Specifically, the 1kHz frequency component only passes through the RC frequency selection circuit 2 with a resonant frequency of 1kHz, activating the corresponding first resistance strain gauge 1 and generating a strain signal with a 1kHz carrier wave; the 2kHz frequency component only passes through the RC frequency selection circuit 2 with a resonant frequency of 2kHz, activating the corresponding second resistance strain gauge 1 and generating a strain signal with a 2kHz carrier wave; and so on. Each resistance strain gauge 1 generates a strain signal only under the excitation voltage at its corresponding resonant frequency, and all other frequency components are filtered out by the corresponding RC frequency selection circuit 2. Through this frequency encoding method, parallel transmission of multiple strain signals on a single bus is achieved.

[0046] Step S5: Drive the scraper to move normally along the grid surface. When the scraper passes a certain resistance strain gauge 1, the bottom of the scraper applies pressure to the upper PET protective layer 3. The pressure is transmitted through the upper PET protective layer 3 to the resistance strain gauge 1 at that position, causing the resistance strain gauge 1 to undergo mechanical deformation.

[0047] In this embodiment, due to the presence of various forces such as pressure, friction and shear between the scraper and the grid during the scraper's movement, these combined forces are reflected in the deformation of the resistance strain gauge 1.

[0048] In step S6, the strain signals output by all resistance strain gauges 1, each carrying its own frequency carrier, are mixed and aggregated together via grounding and signal output bus 6 to form a mixed signal containing all frequency components, which is then uniformly acquired by the single-channel data acquisition module.

[0049] In step S7, the mixed signal acquired by the single-channel data acquisition module is transmitted to the filtering unit. The multiple bandpass filters in the filtering unit work separately. Each bandpass filter only allows the signal with the corresponding center frequency to pass through, filtering out other frequency components, thereby splitting the mixed signal back into multiple independent strain signals and outputting the curves of each strain signal changing with time, so as to realize the synchronous acquisition of strain data at all detection points.

[0050] Step S8: Based on the direct proportionality between the deformation degree of the resistance strain gauge 1 and the change in resistance value, the current value of the strain signal from each channel is converted into the combined force between the scraper and the grid at the corresponding position. This combined force includes the resultant force of pressure, friction, and shear force, which can comprehensively reflect the contact state between the scraper and the grid. The combined force values ​​collected by the resistance strain gauge 1 at different positions are compared laterally. Positions where the deviation of the combined force value exceeds a preset threshold are identified as positions with abnormal adhesion between the scraper and the grid, indicating that there is a gap or excessive pressure between the scraper and the grid at that location, which may affect the slag scraping effect.

[0051] In some embodiments, the method for detecting the fit between the scraper blade of the slag-scraping type grid and the filter grid plate further includes the following steps: The extracted strain signals of each frequency component are transmitted to the host computer. Based on the correspondence between each frequency component and the physical position of the resistance strain gauge 1, the host computer maps the force data to the corresponding coordinate positions, creating a point cloud map of the force changes at each position during the scraper's movement. This visually presents the fit distribution across the entire detection area. When the fit at any position is detected to be lower than the preset standard, the host computer outputs an audible and visual alarm signal to prompt maintenance personnel to handle the situation promptly.

[0052] In summary, by setting up a double-layer PET sandwich structure, the upper and lower PET sheets clamp and fix the resistance strain gauges, protecting the internal components from direct scraping by the scraper and ensuring that all detection points have coplanar surfaces and consistent stress conditions, thus improving the comparability and accuracy of the test results. By using an RC frequency selection circuit in conjunction with multi-frequency hybrid excitation, utilizing the different resonant frequencies of different RC frequency selection circuits, multiple signals on a single bus are differentiated and transmitted through frequency encoding, reducing the multiple signal lines required in traditional solutions to a single bus, significantly simplifying system wiring, reducing hardware costs, and avoiding crosstalk issues between channels in multi-channel acquisition schemes. Through single-channel data acquisition combined with back-end filtering and splitting, all strain signals are mixed and acquired through a single channel, then split by frequency by the back-end filtering unit, achieving true synchronous acquisition and eliminating timing deviation issues common in multi-channel acquisition, resulting in better time consistency in dynamic detection. The matrix array layout, with multiple rows and columns of strain gauges, can simultaneously acquire two-dimensional fit distribution data in both the scraper width and travel directions, which, combined with point cloud diagrams displayed on the host computer, provides intuitive and comprehensive test results. With its dual-mode installation design, it can be disassembled and assembled in the short term to meet the needs of regular inspections, while it can be fixed in the long term to meet the needs of online monitoring, making it widely applicable.

[0053] In the embodiments disclosed in this invention, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments disclosed in this invention according to the specific circumstances.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the fit between the scraper blade of a slag-scraping type grid and a filter grid plate, characterized in that, The adhesion between the scraper and the filter grid plate is measured using a scraper-type grid plate fitting system. The system includes a lower PET support layer, multiple resistance strain gauges arranged in an array on the lower PET support layer, an upper PET protective layer covering the multiple resistance strain gauges, multiple RC frequency selection circuits connected to each resistance strain gauge, a hybrid multi-frequency excitation input bus, a grounding and signal output bus, a multi-frequency hybrid excitation unit, a single-channel data acquisition module, and a filtering unit. Each of the RC frequency selection circuits has a different resonant frequency; the hybrid multi-frequency excitation input bus is connected to the input terminal of each of the RC frequency selection circuits; the grounding and signal output bus is connected to the output terminal of each of the resistance strain gauges; the output terminal of the multi-frequency hybrid excitation unit is connected to the hybrid multi-frequency excitation input bus; the input terminal of the single-channel data acquisition module is connected to the grounding and signal output bus. The input terminal of the filtering unit is connected to the output terminal of the single-channel data acquisition module; The determination method includes the following steps: The measuring system is arranged between the grid plate and the scraper of the scraper-type grid, and the measuring system is fixed to prevent it from being displaced as the scraper moves. The measurement system was calibrated under no-load conditions, and the signal baselines corresponding to each resistance strain gauge were collected and adjusted to zero. The multi-frequency hybrid excitation unit is activated, and a hybrid AC excitation voltage containing multiple different frequency components is input to each of the RC frequency selection circuits through the hybrid multi-frequency excitation input bus; Each of the RC frequency selection circuits selects the excitation voltage component corresponding to its resonant frequency, so that each resistance strain gauge is activated only under the excitation voltage of its corresponding frequency. The drive scraper moves along the surface of the grid plate. When the scraper passes each of the resistance strain gauges, it applies pressure to the upper PET protective layer, causing the resistance strain gauges to deform and output a strain signal carrying the corresponding frequency carrier. All strain signals output by the resistance strain gauges are mixed and collected through the grounding and signal output bus, and then acquired by the single-channel data acquisition module. The filtering unit splits the mixed signal by frequency and extracts the strain signal corresponding to each frequency component. Based on the intensity of each extracted strain signal, the combined force between the scraper and the grid plate at the corresponding position is calculated, and the fit between the scraper and the grid plate is judged by comparing the combined forces at different positions.

2. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, The plurality of resistance strain gauges are full-bridge resistance strain gauges, and the plurality of resistance strain gauges are arranged in a matrix array with multiple rows and columns on the lower PET support layer, with the column direction of the array being consistent with the direction of the scraper's movement.

3. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, Each of the RC frequency selection circuits includes a surface-mount capacitor and a surface-mount resistor. The resonant frequencies of each RC frequency selection circuit are set to increase sequentially from 1kHz, 2kHz, 3kHz... and the frequency interval between adjacent frequency points is 1kHz. The strain gauge and the chip capacitor and chip resistor in the RC frequency selective circuit are fixed to the lower PET support layer by surface mounting, and are sandwiched and covered by the upper PET protective layer and the lower PET support layer to form a sandwich structure.

4. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, The resistance strain gauge is made by directly printing the resistance material onto the inner layer of the PET substrate using FPC embedded resistance, and then covered by the upper PET protective layer and the lower PET support layer to form an integrated sandwich structure.

5. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, The step of performing no-load calibration on the measurement system, acquiring the signal baseline corresponding to each resistance strain gauge and adjusting it to zero, specifically includes: Keep the upper PET protective layer and the lower PET support layer in an unloaded state without external pressure; The output signal of each RC frequency selection circuit at its corresponding resonant frequency point is collected as a baseline value. The baseline values ​​of each frequency point are uniformly adjusted to the zero-point reference to eliminate the effects of initial deformation and circuit offset.

6. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, The step of each of the RC frequency selection circuits selecting the excitation voltage component corresponding to its resonant frequency, so that each resistance strain gauge is activated only under the excitation voltage of its corresponding frequency, specifically includes: The 1kHz frequency component passes only through the RC frequency selection circuit with a resonant frequency of 1kHz, activating the corresponding first resistance strain gauge and generating a strain signal with a 1kHz carrier wave. The 2kHz frequency component passes only through the RC frequency selection circuit with a resonant frequency of 2kHz, activating the corresponding second resistance strain gauge and generating a strain signal with a 2kHz carrier wave. Similarly, each of the resistance strain gauges generates a strain signal only under the excitation voltage at its corresponding resonant frequency, and the other frequency components are filtered out by the corresponding RC frequency selection circuit.

7. The method for determining the fit between the scraper blade and the filter screen plate of the scraper-type grid according to claim 1, characterized in that, The filtering unit includes a multi-bandpass filter, and the passband center frequency of each bandpass filter corresponds to the resonant frequency of one of the RC frequency selection circuits; the step of splitting the mixed signal by frequency through the filtering unit and extracting the strain signal corresponding to each frequency component specifically includes: Each bandpass filter removes other frequency components from the mixed signal, retaining only the strain signal at the corresponding frequency; The strain signal change curves extracted by each bandpass filter are output separately to synchronously acquire the dynamic strain data of all the resistance strain gauges.

8. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, The multi-frequency hybrid excitation unit adopts a working mode of simultaneously outputting a hybrid AC excitation voltage with multiple frequencies superimposed, or adopts a working mode of rapidly switching frequency output; The measurement system also includes a host computer, which is connected to the output of the filtering unit. The determination method further includes: The strain signals of each frequency component extracted are transmitted to the host computer; The host computer draws a point cloud diagram of the force changes at each position during the scraper's movement based on the correspondence between each frequency component and the physical position of the resistance strain gauge. When the fit at any position is detected to be lower than the preset standard, the host computer outputs an alarm signal.

9. The method for determining the fit between the scraper blade and the filter screen plate of the scraper-type grid according to claim 1, characterized in that, The step of calculating the combined force between the scraper and the grid plate at the corresponding positions based on the intensity of each extracted strain signal, and judging the fit between the scraper and the grid plate by comparing the combined forces at different positions, specifically includes: Based on the relationship that the deformation of a resistance strain gauge is proportional to the change in resistance value, the current value of the strain signal is converted into the combined force between the scraper and the grid plate at the corresponding position. The combined force includes the resultant force of pressure, friction and shear. The combined force values ​​collected by the resistance strain gauges at different locations are compared laterally. The location where the deviation of the combined force value exceeds the preset threshold is determined to be the location of abnormal adhesion between the scraper and the grid plate.

10. The method for determining the fit between the scraper blade and the filter screen plate according to claim 1, characterized in that, In the step of arranging the measuring system between the grid plate and the scraper of the scraper-type grid, the measuring system is detachably fixed to the surface of the grid plate in a short-term assembly manner, and the fit test is completed once the scraper runs for one cycle; or the measuring system is fixedly installed on the grid scraper and moves with the scraper for a long time to achieve real-time monitoring. The hybrid multi-frequency excitation input bus is arranged on one side of the lower PET support layer along the scraper travel direction, and the grounding and signal output bus is arranged on the other side of the lower PET support layer. The extension direction of both buses is consistent with the scraper travel direction.

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