A low-noise fluid bed dryer system and control method
By constructing a multi-level collaborative noise reduction system, the problem of multi-source composite noise in the fluidized bed dryer was solved, achieving full-band noise reduction and process compatibility, meeting the high requirements of the pharmaceutical and chemical industries, and balancing noise reduction and fluidization effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG INST OF TECH
- Filing Date
- 2026-04-27
- Publication Date
- 2026-07-14
AI Technical Summary
The multi-source composite noise problem of existing fluidized bed dryer granulators has not been effectively solved. The noise reduction schemes are singular and conflict with process performance, failing to meet the high requirements of the pharmaceutical and chemical industries. Furthermore, existing technologies have not achieved systematic noise reduction across the entire frequency band and the entire process path.
A multi-level collaborative noise reduction system based on the three-level control theory of acoustic source-path-receiver is adopted, including an impedance composite silencer, a multi-layer composite sound insulation cover, an active vibration damping base, a low-noise optimized structure inside the fluidized bed, and a pipe sound-absorbing wrapping layer, forming a full-link collaborative noise reduction, following the design of source noise reduction, path vibration coordination, and process compatibility.
The equipment operating noise has been reduced to below 75dB(A), the airflow resistance does not exceed 8% of the rated air pressure of the fan, meets the GMP standards of the pharmaceutical industry, the fluidization air volume has no attenuation, the material uniformity is high, and the noise reduction effect is significantly better than the existing technology.
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Figure CN122392474A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of granulators, specifically to a low-noise fluidized bed dryer granulator system and control method. Background Technology
[0002] Fluidized bed granulators are core equipment that integrates mixing, granulation, and drying of powdered materials using hot air in a fluidized state. With their advantages of continuous process and ease of operation, they are widely used in pharmaceutical, chemical, and food industries. However, the multi-source composite noise generated during operation has become a major pain point in the industry. According to acoustic classification and actual equipment measurement analysis, the noise sources of traditional fluidized bed granulators are mainly divided into four categories, and these noise sources overlap, resulting in noise levels at a distance of 1 meter from the equipment generally reaching 95-105 dB(A), far exceeding the occupational exposure limit of 85 dB(A) in the "Hygienic Standard for Industrial Enterprise Design" GBZ1-2010, and also failing to meet the requirements of the "Emission Standard for Environmental Noise at the Boundary of Industrial Enterprises" GB12348-2008. Aerodynamic noise: The rotation of the fan impeller, the turbulent flow of high-speed airflow in the duct, and the jetting effect of airflow passing through the traditional straight-hole airflow distribution plate are the main noise sources of the equipment, accounting for 60%-70% of the total noise, with a frequency band of 63-8000Hz. Among them, the main frequency of the fan is concentrated in the low-to-mid frequency band of 250-630Hz, and the jetting noise of the airflow is concentrated in the mid-to-high frequency band of 1000-4000Hz. Mechanical vibration noise: Assembly deviations and wear of transmission components such as bearings, couplings, and gears, as well as the fluidization vibration of the fluidized bed tank, induce structural vibration and radiate noise, with a frequency band of 125-1000Hz. Material impact noise: High-speed collisions between material particles in the fluidized state and the inner wall of the equipment and the airflow distribution plate generate random mid-to-high frequency noise, with a frequency band of 2000-8000Hz. Solid-borne sound and resonance noise: Equipment vibration is transmitted to the building foundation through the frame, inducing secondary radiation noise from the foundation and workshop structure; at the same time, the resonance between the local structure of the equipment and the noise source further amplifies the noise value.
[0003] In existing technologies, some solutions have been proposed to address the noise reduction problem of fluidized bed dryers. The closest existing technology is a fluidized bed dryer described in Chinese Patent Publication No. CN210861954U. This technology uses an anti-collision device on the top of the heating chamber to reduce noise generated during the drying process and protect the integrity of the material. Furthermore, an external condenser pipe connected to the exhaust port separates impurities from the discharged gas, preventing air pollution caused by direct discharge. However, the lack of a damping layer means that vibration radiation noise from the tank wall cannot be suppressed, and vibration radiation noise is one of the main noise sources of fluidized bed dryers.
[0004] Another existing technology, Chinese Patent Publication No. CN110345711A, describes a high-efficiency fluidized bed dryer, comprising: a frustum-shaped material cart with the smaller end of the cart facing downwards; rotating shafts installed horizontally on both sides of the cart; the outer ends of the rotating shafts are mounted on the frame with bearings; an upper body is installed above the cart; one side of the upper body is fixedly connected to the main frame; an upper cylinder and air vents are provided at the top of the upper body; the air vents are sealed and connected to air ducts; the air ducts pass through a soundproof wall and are connected to a fan; a silencer is installed on the fan; a lower body is installed below the cart; a lower cylinder is installed inside the lower body; one side of the lower body is connected to one end of a steam heat exchanger via a pipe; an air filter is installed at the other end of the steam heat exchanger. This design ensures the cleanliness of the dried material, maintains balanced transmission, prevents material accumulation, and achieves more thorough dust removal, while reducing fan noise. However, it does not solve the problems of vibration noise and material impact noise of the fluidized bed itself, and the noise reduction effect is limited.
[0005] In addition, existing noise reduction solutions generally suffer from the following common defects: The noise reduction solutions are simplistic, lacking a systematic design across the entire frequency band and path based on the three-level control theory of acoustic source-path-receiver. They only address a single noise source, failing to resolve the superposition problem of various noise sources, resulting in an overall noise reduction of less than 20 dB(A); Noise reduction severely conflicts with the process, with existing noise reduction structures often sacrificing core drying and granulation process performance for noise reduction effects. For example, silencers increase duct resistance leading to insufficient fluidization airflow, noise reduction designs in airflow distribution plates cause uneven material fluidization, and sound insulation structures affect equipment heat dissipation and cleaning, failing to meet the GMP standards of the pharmaceutical industry and the process requirements of chemical production; Vibration reduction solutions mostly employ passive vibration reduction methods such as rubber pads and metal springs, which can only isolate vibrations at fixed frequencies, unable to adapt to changes in vibration frequency under different operating conditions, with a vibration reduction efficiency of less than 50%, and failing to address the problem of solid-borne sound transmission and secondary radiation noise through the building foundation. The materials of existing noise reduction structures do not match the hygiene, heat resistance, and wear resistance requirements of the pharmaceutical and chemical industries, and are prone to problems such as coating peeling, material adhesion, and unsanitary corners, making them unsuitable for large-scale application in high-requirement production scenarios.
[0006] Existing technologies do not address the multi-source composite noise characteristics of fluidized bed dryers by implementing a coordinated adaptation design across the entire noise chain from source to path to receiver. The noise reduction modules are independent of each other, and there are even issues where the noise reduction effects cancel each other out and conflict with the performance of the drying and granulation process. It is impossible to achieve noise reduction across the entire 63-8000Hz frequency band without sacrificing product quality and production efficiency, and it is also impossible to meet the GMP requirements of the pharmaceutical industry.
[0007] There has long been a technological bias in this field: it is generally believed that the vibration of fluidized bed dryer granulators is a composite vibration of steady-state periodic vibration of the fan and random broadband vibration of fluidized bed material, which is fundamentally different from the single-scenario periodic vibration of automobile engines and the low-frequency micro-vibration characteristics of precision instruments. Active vibration reduction solutions in the automotive and precision instrument fields cannot be adapted to the random broadband vibration of fluidized beds and will significantly increase equipment costs, which does not meet the cost requirements of large-scale production of pharmaceutical and chemical equipment. At the same time, it is generally believed in this field that there is an irreconcilable contradiction between noise reduction and fluidization process. Noise reduction structures will inevitably increase airflow resistance and affect the fluidization effect of materials. Therefore, for a long time, only single and passive noise reduction methods have been used, and a fully collaborative and adapted noise reduction system has never been formed. Summary of the Invention
[0008] The purpose of this invention is to provide a low-noise fluidized bed dryer granulator system and control method to overcome the above-mentioned defects in the prior art.
[0009] A low-noise fluidized bed drying granulator system includes a fluidized bed main unit, a fan unit, and a duct system. It also includes a multi-level collaborative noise reduction system constructed based on the acoustic source-path-receiver three-level control theory. The multi-level collaborative noise reduction system is composed of an impedance composite silencer, a multi-layer composite sound insulation cover, an active vibration damping base, a low-noise optimized structure inside the fluidized bed, a duct sound-absorbing wrapping layer, and a vibration isolation trench. The equipment operating noise does not exceed 75 dB(A) at a distance of 1m from the equipment and a height of 1.5m, and the total airflow resistance is not greater than 8% of the rated air pressure of the fan.
[0010] Preferably, the total sound pressure level satisfies the superposition formula: L p总 =
[0011] In the formula: L p总 Total sound pressure level, measured in dB(A); L Pi The sound pressure level of each sound source is expressed in dB(A). The end-to-end airflow resistance satisfies the following formula: △P 总 ≤0.08XP 风机额定 In the formula: △P 总 P represents the total resistance (Pa); 风机额定 The rated air pressure of the fan (Pa).
[0012] Preferably, the impedance composite silencer is connected in series with the air inlet of the blower and the air outlet of the induced draft fan of the fan unit; the silencer is provided with resistive silencing sections and reactive silencing sections in sequence along the airflow direction, and the noise reduction of the reactive silencing section satisfies the formula: ΔL=10lg{(1+1 / [4(m 1 / m) 2 sin 2 kl]} 1 In the formula: ΔL is the noise reduction, in dB(A); m is the expansion ratio; k is the wavenumber; l is the length of the expansion chamber; The resistive silencing section is filled with sound-absorbing material with a temperature resistance of not less than 200℃, and the inner side is provided with a 304 stainless steel micro-perforated plate protective layer with a pore size of 0.5–1mm and a perforation rate of 20%–30%; the reactive silencing section consists of 2–4 expansion chambers connected in series, matched with a fan main frequency of 250–630Hz, and an airflow resistance coefficient of not more than 0.2.
[0013] Preferably, the multi-layer composite soundproof cover is a detachable and quick-installation structure, covering the periphery of the fluidized bed host, and retaining a 50-100mm closed cavity with the outer wall of the host; the soundproof cover consists of a damping and shock absorption layer, a microporous vacuum layer, and a soundproof outer layer from the inside to the outside. The absolute pressure of the microporous vacuum layer is maintained at 0.02-0.04MPa, and the sealing components have a continuous operating life of not less than 12,000 hours when the vibration speed is not greater than 6.3mm / s.
[0014] Preferably, the active vibration damping base is disposed between the fluidized bed main frame, the fan unit base, and the mounting foundation; the active vibration damping base includes a bladder-type air spring damping module, a piezoelectric vibration sensor, and a fuzzy PID controller, and the vibration transmissibility T satisfies the formula: T= X100% In the formula: T is the vibration transmissibility, in % %. This refers to the vibration amplitude of the equipment. The basic vibration amplitude is set; the controller presets a vibration velocity threshold of 6.3 mm / s and controls the vibration transmissibility T to no more than 5%.
[0015] Preferably, the low-noise optimized structure inside the fluidized bed includes a microporous sintered plate airflow distribution plate and an anti-collision layer; the microporous sintered plate has a pore size of 20–100 μm, an opening rate of 30%–50%, and an airflow uniformity of not less than 95%; the anti-collision layer is made of food-grade polyurethane coating or wear-resistant rubber plate.
[0016] Preferably, the outer wall of all air ducts is covered with the pipe sound-absorbing wrapping layer; the vibration isolation trench is set around the frame of the fluidized bed host, with a width of 100-300mm and a depth of 200-400mm, and is filled with loose vibration-absorbing material with a vibration absorption coefficient of not less than 0.6.
[0017] A low-noise fluidized bed drying granulation control method, employing the aforementioned low-noise fluidized bed drying granulator system, includes the following steps: (1) Before starting, ensure that the alignment deviation of the coupling is no more than 0.1 mm and adjust the initial pressure of the active vibration damping base to 0.3–0.4 MPa; (2) During the pre-start-up phase, the pressure of the microporous vacuum layer of the multi-layer composite soundproof cover is maintained at 0.02–0.04 MPa; (3) Start the fan unit and fluidization system. After the airflow is silenced by the impedance composite silencer, it enters the fluidized bed host evenly. (4) Real-time acquisition of vibration signals, and dynamic adjustment of the bladder-type air spring damping module by a fuzzy PID controller to keep the vibration transmission rate no greater than 5%; (5) A noise monitoring point is set up 1m away from the equipment and 1.5m above it. The noise level will be automatically alarmed when it exceeds 78dB(A). (6) When shutting down, first shut down the process system, and then shut down the fan unit and vacuum device.
[0018] Preferably, during the fluidization process, the airflow is uniformly distributed through the microporous sintering plate airflow distribution plate, with an airflow uniformity of not less than 95%, and the material fluidization is free from deviation and dead zones.
[0019] Preferably, the system operates with the entire link airflow resistance not exceeding 8% of the fan's rated air pressure.
[0020] The beneficial effects achieved by this invention are as follows: This application follows the source-path-receiver three-level control theory, with four modules featuring complementary frequency bands and performance binding to achieve synergistic effects: Source noise reduction complementarity: silencers control low-to-medium frequency fan noise, while microporous sintered plates and anti-collision layers control mid-to-high frequency airflow / impact noise, providing complete coverage. Path-vibration synergy: soundproof enclosures suppress airborne sound transmission, and active vibration damping and vibration isolation trenches block solid-borne sound transmission, preventing resonance amplification. Process-noise reduction compatibility: end-to-end resistance ≤ 8% of the fan's rated air pressure, fluidized airflow with no attenuation, and high material uniformity. Attached Figure Description
[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a flowchart of the present invention. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0023] like Figure 1 As shown, the present invention provides a low-noise fluidized bed drying granulator, including a fluidized bed host, a fan unit, a duct system, and an integrated multi-level collaborative noise reduction system, which consists of an impedance composite silencer, a multi-layer composite sound insulation cover, an active vibration damping base, a low-noise structure inside the fluidized bed, a pipe sound-absorbing wrapping layer, and a vibration isolation trench.
[0024] 1. Impedance composite silencer They are connected in series at the air inlet of the blower and the air outlet of the induced draft fan, respectively.
[0025] The interior is equipped with a resistive noise reduction section and a reactive noise reduction section along the airflow direction.
[0026] Resistive section: Sound-absorbing material with a temperature resistance of ≥200℃, inner side 304 micro-perforated plate, pore diameter 0.5-1mm, perforation rate 20%-30%.
[0027] Resistance section: 2-4 expansion chambers connected in series, matched with a fan main frequency of 250-630Hz.
[0028] Airflow drag coefficient ≤ 0.2, noise reduction ≥ 15 dB(A) across the entire frequency band.
[0029] 2. Multi-layer composite sound insulation cover The detachable and quick-assembly structure covers the fluidized bed main unit, leaving a 50-100mm closed cavity between it and the outer wall (to avoid resonance).
[0030] From the inside out: Damping and vibration reduction layer (5-10mm butyl rubber / asphalt damping plate) → Microporous vacuum layer (30-80mm honeycomb support) → Sound insulation outer layer (2-3mm stainless steel / galvanized plate + polyurethane sound absorption layer).
[0031] Vacuum degree 0.02-0.04MPa (absolute pressure), total sound insulation ≥30dB(A).
[0032] The lifespan of the seal is ≥12000h (vibration velocity ≤6.3mm / s).
[0033] 3. Active vibration damping base It is located between the main unit frame, the fan base, and the mounting foundation.
[0034] Core component: a bladder-type air spring damping module, equipped with a piezoelectric vibration sensor and a fuzzy PID controller.
[0035] Vibration threshold 6.3 mm / s, vibration transmissibility ≤5%, vibration reduction efficiency ≥90%.
[0036] Pressure adjustment range: 0.2-0.8 MPa; response time: ≤50 ms.
[0037] 4. Low-noise internal structure of the fluidized bed Airflow distribution plate: microporous sintered plate (304 / 316L / porous ceramic), pore size 20-100μm, porosity 30%-50%, airflow uniformity ≥95%.
[0038] The inner wall and the upper surface of the distribution plate are equipped with an anti-collision layer: pharmaceutical food-grade polyurethane (3-5mm) and chemical wear-resistant rubber (5-8mm).
[0039] 5. Auxiliary noise reduction structure Duct outer wall: Duct sound-absorbing wrapping layer (rust-proof layer + damping felt + glass wool + metal protective layer).
[0040] The main unit is surrounded by vibration isolation trenches (100-300mm wide and 200-400mm deep), which are filled with vibration-absorbing material.
[0041] Key technology formula 1. Sound Pressure Level Superposition Formula L p总 =
[0042] In the formula: L p总 -Total sound pressure level (dB(A)); L Pi -Sound pressure level of each sound source (dB(A)).
[0043] 2. Vibration transmissibility formula T= X100% Where: T - vibration transmissibility (%); A input - equipment vibration amplitude; A output - foundation vibration amplitude.
[0044] 3. Formula for limiting airflow resistance across the entire process △P total ≤ 0.08XP fan rated Where: △P_total - total resistance (Pa); P_fan_rated - rated wind pressure of the fan (Pa).
[0045] 4. Formula for noise reduction of expansion chamber in reactive silencer ΔL=10lg{(1+1 / [4(m 1 / m) 2 sin 2 kl]} 1 Where: m - expansion ratio; k - wavenumber; l - expansion chamber length.
[0046] Example 1: Pharmaceutical grade FL120 (Cefaclor microcapsules) 1. Equipment Configuration The fluidized bed has a diameter of 1.2m, is made of 316L material, and features a microporous sintered plate with a pore size of 50μm and an open porosity of 40%. Fans: 18.5kW induced draft fan + 11kW forced draft fan, equipped with impedance composite silencer; Soundproof enclosure: 8mm butyl rubber + 50mm vacuum layer + 2mm stainless steel outer layer; Active vibration damping base: 6 sets of bladder-type air springs, fuzzy PID control.
[0047] 2. Process parameters Materials: Cefaclor microspheres, initial moisture content 85.0%, final moisture content 12.0%, processing capacity 100kg / batch.
[0048] 3. Test Results Noise: 72.5dB(A), which meets the requirement of ≤75dB(A); Total resistance: 280Pa, rated fan pressure: 4000Pa, satisfying ΔPtotal ≤ 0.08 × Pfan rated pressure; Vibration transmissibility: 4.5%, satisfying T≤5%; Fluidization uniformity: 96.2%, moisture content deviation ±0.16%.
[0049] Example 2: Chemical grade FL150 (calcium carbonate powder) 1. Equipment Configuration Fluidized bed diameter 1.5m, made of 304 stainless steel, porous ceramic sintered plate, 8mm wear-resistant rubber anti-collision layer; Fans: 22kW induced draft fan + 15kW forced draft fan.
[0050] 2. Test Results Noise: 74.2 dB(A); Fluidization uniformity: 95.5%; Vibration transmissibility: 4.8%.
[0051] Example 3: Comparative Example Adopting the structure of Chinese Patent Publication No. CN210861954U, without a collaborative noise reduction system, the noise level is 98.2 dB(A), the fluidization uniformity is 88.7%, and the product qualification rate is 6.3% lower, proving that the present invention is significantly superior to the prior art.
[0052] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0053] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples. The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.
Claims
1. A low-noise fluidized bed dryer granulator system, characterized in that: The system includes a fluidized bed main unit, a fan unit, and a duct system. Its distinguishing feature is that it also includes a multi-level collaborative noise reduction system constructed based on the acoustic source-path-receiver three-level control theory. The multi-level collaborative noise reduction system is composed of an impedance composite silencer, a multi-layer composite soundproof cover, an active vibration damping base, a low-noise optimized structure inside the fluidized bed, a duct soundproof wrapping layer, and a vibration isolation trench. The equipment operating noise does not exceed 75 dB(A) at a distance of 1m from the equipment and a height of 1.5m, and the total airflow resistance does not exceed 8% of the fan's rated air pressure.
2. The low-noise fluidized bed dryer granulator system according to claim 1, characterized in that, The total sound pressure level satisfies the superposition formula: L p总 = In the formula: L p总 Total sound pressure level, measured in dB(A); L Pi The sound pressure level of each sound source is expressed in dB(A). The end-to-end airflow resistance satisfies the following formula: △P 总 ≤0.08XP 风机额定 In the formula: △P 总 P represents the total resistance (Pa); 风机额定 The rated air pressure of the fan (Pa).
3. The low-noise fluidized bed dryer granulator system according to claim 1, characterized in that, The impedance composite silencer is connected in series with the air inlet of the blower and the air outlet of the induced draft fan in the fan unit; the silencer is equipped with resistive silencing sections and reactive silencing sections in sequence along the airflow direction, and the noise reduction of the reactive silencing section satisfies the formula: ΔL=10lg{(1+1 / [4(m 1 / m) 2 sin 2 kl]} 1 In the formula: ΔL is the noise reduction, in dB(A); m is the expansion ratio; k is the wavenumber; l is the length of the expansion chamber; The resistive silencing section is filled with sound-absorbing material with a temperature resistance of not less than 200℃, and the inner side is provided with a 304 stainless steel micro-perforated plate protective layer with a pore size of 0.5–1mm and a perforation rate of 20%–30%; the reactive silencing section consists of 2–4 expansion chambers connected in series, matched with a fan main frequency of 250–630Hz, and an airflow resistance coefficient of not more than 0.
2.
4. The low-noise fluidized bed dryer granulator system according to claim 1, characterized in that, The multi-layer composite soundproof cover is a detachable and quick-installation structure that covers the periphery of the fluidized bed host, leaving a 50-100mm closed cavity with the outer wall of the host. The soundproof cover consists of a damping and shock absorption layer, a microporous vacuum layer, and a soundproof outer layer from the inside out. The absolute pressure of the microporous vacuum layer is maintained at 0.02-0.04MPa, and the sealing components have a continuous operating life of not less than 12,000 hours when the vibration speed is not greater than 6.3mm / s.
5. The low-noise fluidized bed dryer granulator system according to claim 1, characterized in that, The active vibration damping base is located between the fluidized bed main frame, the fan unit base, and the mounting foundation; the active vibration damping base includes a bladder-type air spring damping module, a piezoelectric vibration sensor, and a fuzzy PID controller, and the vibration transmissibility T satisfies the formula: T= X100% In the formula: T is the vibration transmissibility, in % %. This refers to the vibration amplitude of the equipment. The basic vibration amplitude is set; the controller presets a vibration velocity threshold of 6.3 mm / s and controls the vibration transmissibility T to no more than 5%.
6. The low-noise fluidized bed dryer granulator system according to claim 1, characterized in that, The fluidized bed internal low-noise optimized structure includes a microporous sintered plate airflow distribution plate and an anti-collision layer; the microporous sintered plate has a pore size of 20–100 μm, an opening rate of 30%–50%, and an airflow uniformity of not less than 95%; the anti-collision layer is made of food-grade polyurethane coating or wear-resistant rubber plate.
7. The low-noise fluidized bed dryer granulator system according to claim 1, characterized in that, All ducts are covered with the duct sound-absorbing wrapping layer on their outer walls; the vibration isolation trench is set around the frame of the fluidized bed host, with a width of 100–300 mm and a depth of 200–400 mm, and is filled with loose vibration-absorbing material with a vibration absorption coefficient of not less than 0.
6.
8. A low-noise fluidized bed drying granulation control method, employing the low-noise fluidized bed drying granulator system according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Before starting, ensure that the alignment deviation of the coupling is no more than 0.1 mm and adjust the initial pressure of the active vibration damping base to 0.3–0.4 MPa; (2) During the pre-start-up phase, the pressure of the microporous vacuum layer of the multi-layer composite soundproof cover is maintained at 0.02–0.04 MPa; (3) Start the fan unit and fluidization system. After the airflow is silenced by the impedance composite silencer, it enters the fluidized bed host evenly. (4) Real-time acquisition of vibration signals, and dynamic adjustment of the bladder-type air spring damping module by a fuzzy PID controller to keep the vibration transmission rate no greater than 5%; (5) A noise monitoring point is set up 1m away from the equipment and 1.5m above it. The noise level will be automatically alarmed when it exceeds 78dB(A). (6) When shutting down, first shut down the process system, and then shut down the fan unit and vacuum device.
9. The low-noise fluidized bed drying granulation control method according to claim 8, characterized in that, During the fluidization process, the airflow is uniformly distributed through the microporous sintered plate airflow distribution plate, with an airflow uniformity of not less than 95%, and the material fluidization is free from deviation and dead zones.
10. The low-noise fluidized bed drying granulation control method according to claim 8, characterized in that, Throughout the entire system operation, the airflow resistance across the entire chain must not exceed 8% of the fan's rated air pressure.