A microcapsule spray control method and system based on multi-sensor monitoring

Abstract

The present invention discloses a microcapsule spray control method and system based on multi-sensor monitoring, which relates to the field of microcapsule spray monitoring technology. The method first establishes a temperature correction model for microcapsule particles, realizes the transmission and reception of orthogonal coded microwave signals through a double-layer ring antenna array deployed on the outer wall of the granulation chamber, demodulates the received mixed signal, obtains multiple channel matrices and calculates the complex dielectric constant distribution data of multiple cross-sectional positions. Then, the instantaneous temperature of each cross-sectional position is collected by a temperature sensor to correct the complex dielectric constant distribution data, and the corrected complex dielectric constant distribution data is converted into an instantaneous cross-sectional image. Finally, the working parameters of the primary medium and the secondary medium are dynamically adjusted according to the characteristic difference between the instantaneous cross-sectional image and the standard cross-sectional image, which solves the problem of response lag and measurement distortion of the traditional detection method in a high-temperature dynamic environment, and realizes accurate online monitoring and closed-loop control of the microcapsule granulation process.

Description

Technical Field

[0001] The present invention relates to the technical field of microcapsule spray monitoring, and in particular to a microcapsule spray control method and system based on multi-sensor monitoring. Background Art

[0002] Water molecules have a strong dielectric response to microwaves, enabling highly sensitive in-line measurement of humidity changes in microcapsule particles through resonant frequency shifts and signal attenuation changes. Chinese patent application publication number CN114324096A discloses a method for online detection of particle concentration distribution and humidity during fluidized bed drying. This method measures changes in microwave cavity frequency and combines dielectric models and image reconstruction techniques to invert the particle concentration and humidity distribution within the fluidized bed online. However, microwave cavities only provide a global average dielectric constant and cannot distinguish information from different cross-sections. Iterative calibration relies on the distribution of the ECT, which has low spatial resolution and is susceptible to initial errors, leading to error accumulation. Chinese patent application publication number CN118226444A discloses a microwave imaging method and system, transmitting and receiving terminals, and computer-readable media. This method uses a receiving terminal to orbit around a target to acquire microwave signals and position information scattered by the target, and then uses spectrum analysis and inversion calculations to image the target's cross-section. However, this method uses a single-antenna scanning imaging method that requires mechanical rotation or array switching, resulting in slow imaging speed and inability to capture transient changes in the dynamic spray, resulting in a time lag between the monitoring results and the actual state. Furthermore, high temperatures can easily cause the target dielectric constant to drift, and this method lacks a real-time dielectric compensation mechanism, which can easily lead to image distortion in cross-sectional imaging. Therefore, further improvements to the existing technology are necessary. Summary of the Invention

[0003] In response to the above problems, the present invention provides a microcapsule spray control method and system based on multi-sensor monitoring. This method realizes single-frame instantaneous imaging through a double-layer ring antenna array and orthogonally encoded microwave signals, and then combines a temperature sensor to perform real-time compensation for the dielectric constant, accurately correcting the influence of the high temperature environment on the propagation of microwave signals, thereby obtaining a high-precision instantaneous cross-sectional image inside the granulation chamber.

[0004] The invention objectives of this application can be achieved through the following technical means:

[0005] A microcapsule spray control method based on multi-sensor monitoring includes the following steps:

[0006] Step 1: Deploy double-layer loop antenna arrays and temperature sensors at multiple cross-sections of the outer wall of the granulation chamber. Each double-layer loop antenna array includes multiple sets of outer-ring transmitting antennas and inner-ring receiving antennas.

[0007] Step 2: Measure the complex dielectric constant of standard microcapsule particles at different instantaneous temperatures, build a temperature correction model, and preset the template characteristics of the granulation chamber at multiple working hours;

[0008] Step 3: Prepare suspended materials using oily core materials and water-based wall materials, spray the suspended materials into the granulation chamber, transport the primary medium into the granulation chamber, and recover the secondary medium from the granulation chamber;

[0009] Step 4: Each group of transmitting antennas simultaneously transmits orthogonally encoded microwave signals, and the corresponding receiving antennas synchronously collect the mixed signals;

[0010] Step 5: Demodulate each group of mixed signals to obtain multiple channel matrices, and calculate the complex dielectric constant distribution data of multiple cross-sectional positions based on the channel matrices;

[0011] Step 6: The temperature sensor collects the instantaneous temperature at multiple cross-sectional locations, and corrects the complex dielectric constant distribution data at the corresponding cross-sectional locations based on the instantaneous temperature and the temperature correction model;

[0012] Step 7: extracting the dielectric constant of the complex dielectric constant distribution data, and converting the complex dielectric constant distribution data into an instantaneous cross-sectional image based on the dielectric constant;

[0013] Step 8: Extract the standard cross-sectional image from the template features, calculate the feature difference between the instantaneous cross-sectional image and the standard cross-sectional image, and adjust the working parameters of the primary medium and the secondary medium according to the feature difference.

[0014] In the present invention, in step 2, the complex dielectric constant ε=ε'+jε'', and the temperature correction model is: and , where the real part ε' is the dielectric constant, the imaginary part ε'' is the loss factor, Δε' is the real part change of the real part ε', Δε'' is the imaginary part change of the imaginary part ε'', j is the imaginary unit, ε'0 is the dielectric constant of the standard microcapsule particles at the reference temperature, ε''0 is the loss factor of the standard microcapsule particles at the reference temperature, T is the instantaneous temperature, T0 is the reference temperature, α is the real temperature coefficient, and β is the imaginary temperature coefficient.

[0015] In the present invention, in step 3, the oily core material is plant essential oil, thymol ≥ 13.5wt% and cinnamaldehyde ≥ 6.5wt% in the plant essential oil, the aqueous wall material is an aqueous solution of dextrin and starch, and the mass ratio of the oily core material to the aqueous wall material in the suspended material is 1:4 to 1:6.

[0016] In the present invention, in step 5, the cross section of the granulation chamber is discretized into a pixel grid, and based on the initial complex dielectric constant of the pixel grid, a theoretical channel matrix H' is generated by a forward simulation algorithm, and an error function between the channel matrix H and the theoretical channel matrix H' is constructed. The complex dielectric constant ε of each pixel grid is gradually updated by solving the error function, and finally the complex dielectric constant distribution data is generated.

[0017] In the present invention, in step 6, the real part change Δε' and the imaginary part change Δε'' are obtained according to the temperature correction model and the instantaneous temperature, the complex dielectric constant change Δε=Δε'+jΔε'', and the complex dielectric constant change Δε of the complex dielectric constant distribution data is eliminated to obtain the corrected complex dielectric constant distribution data.

[0018] In the present invention, in step 7, the dielectric constant range is calculated, and each dielectric constant in the complex dielectric constant distribution data is mapped to a grayscale value according to the dielectric constant range to obtain an instantaneous cross-sectional image.

[0019] In the present invention, in step 8, the grayscale value difference between the instantaneous cross-sectional image and the corresponding standard cross-sectional image at each cross-sectional position is calculated respectively, and then the characteristic difference of the granulation chamber is obtained.

[0020] In the present invention, in step 8, a parameter template is preset, which includes the working parameters of the primary medium and the secondary medium with multiple working times. If the absolute value of the characteristic difference is greater than the difference threshold D1, the working parameters of the primary medium and the secondary medium are adjusted, and the adjustment range of each working parameter is calculated at the same time.

[0021] A spray control system for implementing the microcapsule spray control method based on multi-sensor monitoring, comprising: a granulation chamber, a temperature sensor, a hot air device, a double-layer loop antenna array, a parameter controller, a data processing unit, and a data analysis unit, wherein:

[0022] The granulation chamber is configured to contain the suspended material;

[0023] The hot air device is configured to output the primary medium to the granulation chamber and recover the secondary medium;

[0024] The temperature sensor is configured to collect instantaneous temperatures at multiple cross-sectional locations of the granulation chamber;

[0025] The double-layered loop antenna array is configured to transmit microwave signals into the pelletizing chamber and collect the mixed signals;

[0026] The data processing unit is configured to generate an instantaneous cross-sectional image according to the mixed signal and the instantaneous temperature, and generate a characteristic difference between the instantaneous cross-sectional image and a standard cross-sectional image;

[0027] The data analysis unit is configured to generate an adjustment instruction based on the characteristic difference;

[0028] The parameter controller is configured to adjust the operating parameters of the primary medium and the secondary medium according to the adjustment instruction.

[0029] In the present invention, the granulation chamber has an atomizing nozzle and a rotating wall, and the material flow rate of the suspended material, the atomizing pressure and the rotating speed of the rotating wall are adjusted according to the equivalent diameter of the particle profile in the granulation chamber.

[0030] The implementation of the microcapsule spray control method and system based on multi-sensor monitoring of the present invention has the following beneficial effects: First, a double-layer loop antenna array combined with orthogonally encoded microwave signals achieves single-frame instantaneous imaging and generates instantaneous complex dielectric constant distribution data, solving the problem of dynamic response lag of traditional microwave imaging and accurately capturing transient changes in microcapsule particles. The instantaneous temperature is then acquired in real time using a temperature sensor, and the complex dielectric constant in the complex dielectric constant distribution data is corrected based on the instantaneous temperature, compensating for the impact of the high temperature environment on the microwave signal and improving the accuracy of the complex dielectric constant distribution data. Furthermore, by comparing standard cross-sectional images with instantaneous cross-sectional images at multiple cross-sectional positions, closed-loop control of the primary and secondary media is achieved, ensuring the uniformity and stability of the microcapsule particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the microcapsule spray control method based on multi-sensor monitoring of the present invention;

[0032] Figure 2 Schematic diagram of a double-layer loop antenna array;

[0033] Figure 3 is an instantaneous cross-sectional image of the present invention;

[0034] Figure 4 is another instantaneous cross-sectional image of the present invention;

[0035] Figure 5 is a schematic diagram of multiple sets of template features of the present invention;

[0036] Figure 6 is a block diagram of the spray control system of the present invention;

[0037] Figure 7 Schematic diagram of the granulation chamber of the present invention;

[0038] Figure 8 Schematic diagram of the microcapsule granulation production line of the present invention.

[0039] Reference numerals in the accompanying drawings: granulation chamber 10, material bin 11, finished product bin 12, cyclone recovery device 13, medium bin 14, heat exchanger 15, pressure pump 16, first controller 21, second controller 22, third controller 23, fourth controller 24, fifth controller 25, sixth controller 26. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0041] In the industrial production of microcapsules, accurate monitoring and control of their humidity is a key factor in ensuring product quality. Appropriate humidity levels directly impact microcapsule molding quality, encapsulation efficiency, and product stability. However, existing technologies for measuring microcapsule humidity have significant limitations. Traditional offline sampling methods (such as loss on drying) are not only time-consuming but also disrupt production continuity. Near-infrared spectroscopy, while capable of online detection, suffers from signal saturation in high-concentration suspensions and exhibits significant error for microcapsules smaller than 50 μm. While electrical capacitance tomography offers a fast response, its accuracy decreases dramatically in high-temperature environments due to the nonlinear relationship between dielectric constant and humidity. These methods fail to meet the demand for real-time, precise monitoring of the microcapsule granulation process. To address these challenges, the present invention combines orthogonally coded microwave tomography with a distributed temperature sensing network. This approach utilizes a double-layer loop antenna array to achieve millisecond-level high-speed imaging. Combined with a pre-established temperature correction model, this method compensates for the effects of high temperatures on humidity measurements in real time, enabling high-precision dynamic monitoring of microcapsule humidity. Example 1

[0042] Reference Figure 1 The microcapsule spray control method based on multi-sensor monitoring of the present invention described in detail in this embodiment includes the following steps.

[0043] Step 1: Deploy double-layer loop antenna arrays and temperature sensors at multiple cross-section positions on the outer wall of the granulation chamber. Each set of double-layer loop antenna arrays includes multiple sets of outer ring transmitting antennas and inner ring receiving antennas. Figure 2Each cross-sectional location is equipped with a double-layer loop antenna array, with 8 to 24 transmitting antennas and 16 to 48 receiving antennas. The radial spacing between the receiving and transmitting antennas is 1.5 to 2 times the wall thickness of the granulation chamber, and the axial spacing between the double-layer loop antenna arrays at adjacent cross-sectional locations is 0.3 to 1.2 times the diameter of the granulation chamber. In this embodiment, there are four double-layer loop antenna arrays. The transmitting antennas are microstrip patch antennas secured by a high-temperature ceramic substrate, and the receiving antennas are helical antennas secured by a stainless steel bracket. A silicone rubber insulation layer is placed between the stainless steel bracket and the outer wall of the granulation chamber. Each double-layer loop antenna array corresponds to at least one temperature sensor, such as a thermocouple sensor.

[0044] Step 2: Measure the complex dielectric constant of the standard microcapsule particles at different instantaneous temperatures, build a temperature correction model, and preset the template characteristics of the granulation chamber at multiple working hours. The humidity of the standard microcapsule particles is less than or equal to 1%. Low humidity can avoid the interference of moisture on the complex dielectric constant during the construction of the temperature correction model. Use, for example, a dielectric spectrometer to scan the standard microcapsule particles at different instantaneous temperatures. The complex dielectric constant ε=ε'+jε'', record the real part ε' and imaginary part ε'' of the complex dielectric constant of the standard microcapsule particles at each instantaneous temperature, and calculate the real part change Δε' of the real part ε' and the imaginary part change Δε'' of the imaginary part ε''. Establish a temperature correction model: and , where the real part ε' is the dielectric constant, the imaginary part ε'' is the loss factor, j is the imaginary unit, ε'0 is the dielectric constant of a standard microcapsule particle at a reference temperature, ε''0 is the loss factor of a standard microcapsule particle at a reference temperature, T is the instantaneous temperature, T0 is the reference temperature, α is the real temperature coefficient, and β is the imaginary temperature coefficient. The reference temperature T0 is, for example, 25°C.

[0045] Step 3: Prepare a suspension using an oily core material and an aqueous wall material. The suspension is sprayed into the granulation chamber, a primary medium is delivered to the granulation chamber, and a secondary medium is recovered from the granulation chamber. The oily core material is a plant essential oil containing 13.5% or more thymol and 6.5% or more cinnamaldehyde by weight. The aqueous wall material is an aqueous solution of dextrin and starch. The mass ratio of the oily core material to the aqueous wall material in the suspension is 1:4 to 1:6. The primary medium is the high-temperature gas (air or nitrogen) entering the granulation chamber. The secondary medium is the gas exhausted from the granulation chamber, containing volatilized gaseous water and a small amount of residual microcapsule particles.

[0046] Step 4: Each group of transmitting antennas simultaneously transmits orthogonally coded microwave signals, and the corresponding receiving antennas synchronously collect the mixed signal. The orthogonally coded microwave signals can be generated using any of frequency division orthogonalization, code division orthogonalization, or time division orthogonalization. This embodiment uses frequency division orthogonalization to generate orthogonally coded microwave signals. Each group of transmitting antennas simultaneously transmits orthogonally coded microwave signals (at different frequencies). The mixed signal is the superposition of the signals from all transmitting antennas. For the specific method of generating microwave signals, refer to Example 2.

[0047] Step 5: Demodulate each mixed signal to obtain multiple channel matrices. Calculate the complex permittivity distribution data for multiple cross-sectional locations based on the channel matrices. Separate the mixed signals using a fast Fourier transform (FFT) to generate the channel matrix H. Discrete the cross section of the granulation chamber into a pixel grid. Based on the initial complex permittivity of the pixel grid, generate a theoretical channel matrix H' using a forward simulation algorithm. The theoretical channel matrix has the same dimensions as the channel matrix. Construct the error function between the channel matrix H and the theoretical channel matrix H': min||H - H'(ε)|| 2 +λ||▽ε|| 2 , solving the error function and gradually optimizing the complex dielectric constant ε of each pixel grid, ultimately generating complex dielectric constant distribution data, where λ is the regularization parameter, H'(ε) is the theoretical channel matrix obtained based on the complex dielectric constant ε, and ▽ε is the spatial gradient of the complex dielectric constant. For a specific implementation, refer to Example 2.

[0048] Step 6: The temperature sensor collects instantaneous temperatures at multiple cross-sectional locations. The complex permittivity distribution data at the corresponding cross-sectional locations is corrected based on the instantaneous temperatures and the temperature correction model. The real and imaginary changes, Δε', are calculated based on the temperature correction model and the instantaneous temperatures. The complex permittivity change, Δε, is calculated as Δε' + jΔε'. The complex permittivity change, Δε, is removed from the complex permittivity distribution data to obtain the corrected complex permittivity distribution data.

[0049] Step 7: Extract the dielectric constant of the complex dielectric constant distribution data, and convert the complex dielectric constant distribution data into an instantaneous cross-sectional image based on the dielectric constant. Set the humidity range, obtain the dielectric constant range according to the humidity range, and map each dielectric constant in the complex dielectric constant distribution data to a grayscale value according to the dielectric constant range to obtain an instantaneous cross-sectional image. Figure 3 and Figure 4 The change of the gray value of the instantaneous cross-sectional image can reflect the humidity distribution of the microcapsule particles in the granulation chamber, and the gray value is positively correlated with the dielectric constant ε'.

[0050] In this embodiment, the humidity range is set to (0%, 100%), the dielectric constant ε' of water is approximately 80, and the dielectric constant ε' of the dry material is approximately 2, so the dielectric constant range is (2, 80). The complex dielectric constant ε of each pixel grid in the complex dielectric constant distribution data is ε'-jε''. The dielectric constant ε' is mapped to a 256-level instantaneous cross-sectional image through piecewise linear mapping: when ε'<2, the grayscale value G is set to 0 (pure black); when 20>ε'≧2, the grayscale value G=round(12.75×ε'-25.5); when 80>ε'≥20, the grayscale value G=round(2.55×ε'+178.5); when ε'≧80, the grayscale value G is set to 255 (pure white), and the instantaneous cross-sectional image is finally generated.

[0051] In another embodiment, the humidity of the suspended material is taken as the maximum humidity, and the humidity of the standard microcapsule particles is taken as the minimum humidity. The humidity of the suspended material is 40%, and the humidity of the standard microcapsule particles is 1%. Then the humidity range is (1%, 40%), and the dielectric constant range is (2.5, 50). The dielectric constant ε' is linearly mapped to an instantaneous cross-sectional image with 256 levels of grayscale: when ε'<2.5, the grayscale value G is set to 0, when 50>ε'≧2.5, G=round(5.36×(ε'-2.5)), and when ε'≧50, the grayscale value G is set to 255 to generate an instantaneous cross-sectional image.

[0052] Step 8: Extract the standard cross-sectional image from the template features, calculate the characteristic difference between the instantaneous cross-sectional image and the standard cross-sectional image, and adjust the working parameters of the primary medium and the secondary medium according to the characteristic difference. Acquire multiple sets of instantaneous cross-sectional images, calculate the grayscale value difference between the instantaneous cross-sectional image and the corresponding standard cross-sectional image at each cross-sectional position, and use the average value of the multiple sets of grayscale value differences as the characteristic difference of the granulation chamber. Preset a parameter template, which includes the working parameters of the primary medium and the secondary medium with multiple working times. If the absolute value of the characteristic difference is greater than the difference threshold D1, adjust the working parameters of the primary medium and the secondary medium, and calculate the adjustment range of each working parameter. Refer to Example 3 for details. Set the difference threshold D1 according to the production process requirements. In this embodiment, the characteristic difference is calculated based on the pixel grayscale value (0 to 225) as the basic unit, and the setting range of D1 is 10-30. Example 2

[0053] This embodiment further discloses a method for generating microwave signals and complex permittivity distribution data using frequency division quadrature. The microcapsules in the granulation chamber are in high-speed motion. Frequency division quadrature generates microwave signals of different frequencies to avoid motion interference, making it suitable for high-speed dynamic environments such as the present invention.

[0054] Determine the center frequency. Based on the radius R of the granulation chamber and the loss factor ε'' of the microcapsule particles, the center frequency f' of the microwave signal is selected. The center frequency range is usually 1-5GHz (corresponding to R = 0.25-1.5 meters). The specific calculation formula is: , where c is the speed of light and ε'' reflects the absorption characteristics of the microcapsules for microwave signals. The double-layered annular antenna array on the outer wall of the granulation chamber consists of N transmitting antennas in the outer ring and M receiving antennas in the inner ring. The spacing between the transmitting antennas and the receiving antennas is typically less than 5 cm.

[0055] Construct the channel matrix. Determine the total bandwidth B, satisfying B>2v max f' / c, where v max (can be estimated based on the maximum medium flow velocity of the primary medium) is the maximum movement speed of the microcapsule particles. The total bandwidth B is evenly divided into K orthogonal subcarriers (interval Δf = B / K), that is, the frequency f of the kth orthogonal subcarrier k =f'-B / 2+(k-1)Δf, and then evenly divide the K orthogonal subcarriers into N subcarrier groups (KmodN=0). Each subcarrier group contains multiple continuous orthogonal subcarriers, and each transmitting antenna is assigned a unique subcarrier group. The transmitting antenna generates a microwave signal based on the assigned subcarrier group and transmits it simultaneously. The receiving antenna synchronously collects the mixed signal, demodulates the mixed signal through the fast Fourier transform algorithm, and separates the channel response H corresponding to each orthogonal subcarrier. i,n,m , construct the I×N×M dimensional channel matrix H, where I=K / N, H i,n,m Characterize the channel response of orthogonal subcarrier i between transmit antenna n and receive antenna m, where i=1, 2, ..., I, n=1, 2, ..., N, and m=1, 2, ..., M.

[0056] Generate complex dielectric constant distribution data, discretize the cross section of the granulation chamber into a pixel grid, and set an initial complex dielectric constant for each pixel grid. In this embodiment, a forward propagation model is constructed based on the initial complex dielectric constant, the number of transmitting antennas N, the number of receiving antennas M, and the number of orthogonal subcarriers I for each transmitting antenna. The forward propagation model is used to calculate the theoretical channel response under each propagation path, thereby constructing an I×N×M-dimensional theoretical channel matrix H'. In another embodiment, the finite element method is used to solve Maxwell's equations to simulate the propagation of microwave signals under the current initial complex dielectric constant and calculate the theoretical channel matrix H'. The error function min||H-H'(ε)|| between the channel matrix H and the theoretical channel matrix H' is constructed. 2 +λ||▽ε|| 2, solve the error function, and finally obtain the complex dielectric constant ε of each pixel grid, and generate the complex dielectric constant distribution data, where H'(ε) is the theoretical channel matrix obtained by forward calculation based on the complex dielectric constant ε, λ is the regularization parameter, and ▽ε is the spatial gradient of the complex dielectric constant. Example 3

[0057] like Figure 5 This embodiment further discloses a preferred method for adjusting the working parameters of the primary medium and the secondary medium in step 8. The working parameters of the primary medium include the medium flow rate V1 and the medium temperature T', and the working parameter of the secondary medium is the medium pressure F1. The standardized operating process of microcapsule spray granulation mainly includes four stages: preheating, curing, fluidization and collection. The present invention is mainly aimed at spray control during the curing stage. Therefore, a preferred parameter template includes at least the working parameters of the curing stage, as shown in the following table (the unit of the working time t is min).

[0058]

[0059] In this embodiment, four sets of double-layered loop antenna arrays are installed on the outer wall of the granulation chamber, and four sets of instantaneous cross-sectional images are generated during each operating period. The grayscale value mean μ1 of each set of instantaneous cross-sectional images and the grayscale value mean μ2 of the corresponding standard cross-sectional image are calculated to obtain a grayscale value difference Δμ = μ1-μ2. The average value of the four sets of grayscale value differences Δμ is used as the characteristic difference Δ1. If the absolute value of the characteristic difference is greater than the difference threshold D1, the adjustment parameter δ1 = Δ1 / 255 is calculated. The adjustment range of the medium flow rate is ΔV1 = δ1V1, the adjustment range of the medium temperature is ΔT = δ1T', and the adjustment range of the medium pressure is ΔF1 = δ1F1. The primary and secondary media are adjusted according to the adjustment range. Example 4

[0060] like Figure 6 , the spray control system of the present invention for realizing the microcapsule spray control method based on multi-sensor monitoring includes: a granulation chamber, a temperature sensor, a hot air device, a double-layer ring antenna array, a parameter controller, a data processing unit, and a data analysis unit. Among them, the granulation chamber is configured to accommodate suspended materials. The hot air device is configured to output the primary medium to the granulation chamber and recover the secondary medium. The temperature sensor is configured to collect the instantaneous temperature of multiple cross-sectional positions in the granulation chamber. The double-layer ring antenna array is configured to transmit microwave signals to the granulation chamber and collect mixed signals. The data processing unit is configured to generate an instantaneous cross-sectional image based on the mixed signal and the instantaneous temperature, and generate a characteristic difference between the instantaneous cross-sectional image and the standard cross-sectional image. The data analysis unit is configured to generate an adjustment instruction based on the characteristic difference. The parameter controller is configured to adjust the working parameters of the primary medium and the secondary medium according to the adjustment instruction. As Figure 7The granulation chamber has an atomizing nozzle and a rotating wall, and the material flow rate, atomizing pressure and rotating wall speed of the suspended material are adjusted according to the equivalent diameter of the particle profile in the granulation chamber.

[0061] like Figure 8 The spray control system shown is applied to a microcapsule granulation production line. A material silo 11 passes a suspended material mixture of oily core material and aqueous wall material into the granulation chamber 10, and a pressure pump 16 sprays the primary medium into the granulation chamber 10. The finished product silo 12 recovers the microcapsule particles. The cyclone collector 13 recovers the secondary medium. Residual microcapsule particles in the secondary medium are recycled back to the finished product silo 12. The secondary medium passes through the medium silo 14 and heat exchanger 15 before returning to the pressure pump 16. The parameter template consists of operating parameters for the primary and secondary media over multiple operating times. Specifically, the first controller 21 adjusts the flow rate of the suspended material. The second controller 22 adjusts the atomization pressure of the suspended material. The third controller 23 adjusts the operating parameters of the primary medium (medium flow rate). The fourth controller 24 adjusts the operating parameters of the primary medium (medium temperature). The fifth controller 25 adjusts the operating parameters of the secondary medium (medium pressure). The sixth controller 26 adjusts the rotation speed of the rotating wall. Example 5

[0062] Furthermore, the present invention can also adjust the working parameters of the suspended material and the rotating wall during the solidification stage. Specifically, first collect a vertical image in the granulation chamber, obtain the particle outline in the vertical image, use the equivalent area method, for example, to calculate the equivalent diameter E of the particle outline, and calculate the particle size difference Δ2 between the equivalent diameter E and the standard particle size E'. If the absolute value of the particle size difference is greater than the difference threshold D2, then adjust the working parameters of the suspended material and the rotating wall. The working parameters of the suspended material include the material flow rate V2 and the atomization pressure F2, and the working parameter of the rotating wall is the rotation speed Q. Calculate the adjustment parameter δ2=Δ2 / E', then the adjustment range of the material flow rate ΔV2=δ2V2, the adjustment range of the atomization pressure ΔF2=δ2F2, and the adjustment range of the rotation speed ΔQ=δ2Q, and adjust the suspended material and the rotating wall according to the adjustment range.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A microcapsule spray control method based on multi-sensor monitoring, characterized in that: The following steps are involved: Step 1: Deploy double-layer loop antenna arrays and temperature sensors at multiple cross-sections of the outer wall of the granulation chamber. Each double-layer loop antenna array includes multiple sets of outer-ring transmitting antennas and inner-ring receiving antennas. Step 2: Measure the complex dielectric constant of standard microcapsule particles at different instantaneous temperatures, build a temperature correction model, and preset the template characteristics of the granulation chamber at multiple working hours; Step 3: Prepare suspended materials using oily core materials and water-based wall materials, spray the suspended materials into the granulation chamber, transport the primary medium into the granulation chamber, and recover the secondary medium from the granulation chamber; Step 4: Each group of transmitting antennas simultaneously transmits orthogonally encoded microwave signals, and the corresponding receiving antennas synchronously collect the mixed signals; Step 5: Demodulate each group of mixed signals to obtain multiple channel matrices, and calculate the complex dielectric constant distribution data of multiple cross-sectional positions based on the channel matrices; Step 6: The temperature sensor collects the instantaneous temperature at multiple cross-sectional locations, and corrects the complex dielectric constant distribution data at the corresponding cross-sectional locations based on the instantaneous temperature and the temperature correction model; Step 7: extracting the dielectric constant of the complex dielectric constant distribution data, and converting the complex dielectric constant distribution data into an instantaneous cross-sectional image based on the dielectric constant; Step 8: Extract the standard cross-sectional image from the template features, calculate the feature difference between the instantaneous cross-sectional image and the standard cross-sectional image, and adjust the working parameters of the primary medium and the secondary medium according to the feature difference. In step 2, the complex dielectric constant ε = ε' + jε'', and the temperature correction model is: and , where the real part ε' is the dielectric constant, the imaginary part ε'' is the loss factor, Δε' is the real part change of the real part ε', Δε'' is the imaginary part change of the imaginary part ε'', j is the imaginary unit, ε'0 is the dielectric constant of the standard microcapsule particles at the reference temperature, ε''0 is the loss factor of the standard microcapsule particles at the reference temperature, T is the instantaneous temperature, T0 is the reference temperature, α is the real temperature coefficient, β is the imaginary temperature coefficient, In step 5, the cross section of the granulation chamber is discretized into a pixel grid. Based on the initial complex dielectric constant of the pixel grid, the theoretical channel matrix H' is generated by the forward simulation algorithm. The error function between the channel matrix H and the theoretical channel matrix H' is constructed. The complex dielectric constant ε of each pixel grid is gradually updated by solving the error function, and finally the complex dielectric constant distribution data is generated. In step 6, the real part change Δε' and the imaginary part change Δε'' are obtained according to the temperature correction model and the instantaneous temperature. The complex dielectric constant change Δε=Δε'+jΔε'' is obtained. The complex dielectric constant change Δε of the complex dielectric constant distribution data is eliminated to obtain the corrected complex dielectric constant distribution data.

2. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that: In step 3, the oily core material is plant essential oil, thymol ≥ 13.5 wt% and cinnamaldehyde ≥ 6.5 wt% in the plant essential oil, the aqueous wall material is an aqueous solution of dextrin and starch, and the mass ratio of the oily core material to the aqueous wall material in the suspended material is 1:4 to 1:

6.

3. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that: In step 7, the dielectric constant range is calculated, and each dielectric constant in the complex dielectric constant distribution data is mapped to a grayscale value according to the dielectric constant range to obtain an instantaneous cross-sectional image.

4. The microcapsule spray control method based on multi-sensor monitoring according to claim 3, characterized in that: In step 8, the grayscale value difference between the instantaneous cross-sectional image and the corresponding standard cross-sectional image at each cross-sectional position is calculated, and then the characteristic difference of the granulation chamber is obtained.

5. The microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that: In step 8, a parameter template is preset, which includes the working parameters of the primary medium and the secondary medium with multiple working times. If the absolute value of the characteristic difference is greater than the difference threshold D1, the working parameters of the primary medium and the secondary medium are adjusted, and the adjustment range of each working parameter is calculated at the same time.

6. A spray control system for implementing the microcapsule spray control method based on multi-sensor monitoring according to claim 1, characterized in that: include: Granulation chamber, temperature sensor, hot air equipment, double-layer ring antenna array, parameter controller, data processing unit, data analysis unit, among which, The granulation chamber is configured to contain the suspended material; The hot air device is configured to output the primary medium to the granulation chamber and recover the secondary medium; The temperature sensor is configured to collect instantaneous temperatures at multiple cross-sectional locations of the granulation chamber; The double-layered loop antenna array is configured to transmit microwave signals into the pelletizing chamber and collect the mixed signals; The data processing unit is configured to generate an instantaneous cross-sectional image according to the mixed signal and the instantaneous temperature, and generate a characteristic difference between the instantaneous cross-sectional image and a standard cross-sectional image; The data analysis unit is configured to generate an adjustment instruction based on the characteristic difference; The parameter controller is configured to adjust the operating parameters of the primary medium and the secondary medium according to the adjustment instruction.

7. The spray control system according to claim 6, characterized in that: The granulation chamber is provided with an atomizing nozzle and a rotating wall, and the material flow rate of the suspended material, the atomizing pressure and the rotating speed of the rotating wall are adjusted according to the equivalent diameter of the particle profile in the granulation chamber.

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