A low-broken-rice-rate rice mill pressure automatic adjusting device and adjusting method

Abstract

This invention discloses an automatic pressure adjustment method and equipment for a rice milling machine with low broken rice rate, relating to the field of grain processing machinery and equipment. It aims to solve the problems of high broken rice rate, slow pressure adjustment, and poor heat dissipation in traditional rice milling equipment. The equipment, based on a frame, integrates milling execution, pressure adjustment, temperature detection, low-temperature heat dissipation, central control, hulling and bran removal, and discharge components. Coaxially arranged milling rollers, a whitening chamber, and a radially sliding screen form an annular milling gap. Combined with the pressure adjustment components, automatic control of milling pressure is achieved. A dual internal and external heat dissipation structure strictly controls the milling temperature, and bran powder is removed in real time to prevent accumulation. This invention achieves closed-loop precise adjustment of milling pressure, effectively reducing the broken rice rate, improving the quality of finished rice, and features a high degree of automation, making it suitable for continuous and refined rice processing.

Description

Technical Field

[0001] This invention relates to the field of rice processing equipment technology, and in particular to an automatic pressure adjustment device and method for a rice milling machine with a low broken rice rate. Background Technology

[0002] Rice milling machines are core equipment in the rice processing process, and their performance directly affects the processing quality and broken rice rate. Currently, low-temperature rice milling technology has become an important direction in the industry for reducing rice temperature and breaking rice. For example, patent CN2673493Y discloses a low-temperature rice milling machine with a multi-air intake structure. By setting axial hollow air intake holes and radial holes on the rotating shaft installed in the rice milling chamber, and cooperating with the air intake of the shell, multiple air intakes are achieved, increasing the air volume in the whitening chamber to reduce the rice milling temperature. At the same time, the air intake holes of the feeding hopper seat and the air intake of the cooling hopper further assist in cooling, which to a certain extent solves the problems of excessively high rice temperature and high broken rice rate in traditional rice milling machines.

[0003] However, the aforementioned patent still has significant technical defects, making it difficult to meet the demands of modern rice processing for low broken rice rate and automated adjustment: First, the patent only focuses on reducing rice temperature through a multi-air intake structure, without addressing the adjustment mechanism for milling pressure. The pressure is fixed during milling and cannot be dynamically adjusted according to material characteristics and milling progress. This can easily lead to an increased broken rice rate due to excessive pressure, or insufficient milling precision due to insufficient pressure. Second, its cooling structure relies solely on air cooling, resulting in limited cooling efficiency. Furthermore, it lacks a temperature detection and automatic control mechanism, making it impossible to monitor the temperature inside the milling chamber in real time and adjust the heat dissipation intensity accordingly, thus making it difficult to maintain a stable low-temperature milling environment. Third, the discharge and bran suction structures of this patent are all fixed designs, lacking linkage control with temperature and pressure. The overall level of automation is low, requiring manual intervention for adjustment, resulting in poor processing efficiency and consistency.

[0004] To address the shortcomings of existing technologies, this invention provides an automatic pressure adjustment device for a low-broken-rice rice milling machine. By integrating automatic pressure adjustment, real-time temperature monitoring, and coordinated heat dissipation functions, it solves the problems of unadjustable pressure, unstable cooling effect, and high broken rice rate and poor processing quality caused by low automation in existing low-temperature rice milling machines. This further improves the stability and economy of rice milling, meeting the production needs of modern large-scale, refined, and automated rice processing. This invention achieves dynamic adaptive adjustment of milling pressure through a pressure adjustment unit, and, in conjunction with the coordinated control of a temperature detection module and a low-temperature heat dissipation module, stably maintains a low-temperature milling environment. Simultaneously, a central control module enables collaborative work among all units, reducing manual intervention, improving processing consistency, effectively reducing the broken rice rate, and balancing processing efficiency and quality, thus filling a gap in existing technologies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an automatic pressure adjustment device and method for a rice milling machine with low broken rice rate. It aims to solve the technical problems of traditional rice milling equipment, such as lagging pressure adjustment, poor heat dissipation, high broken rice rate due to bran accumulation, and low automation. Through automated closed-loop pressure control, internal and external coordinated heat dissipation, and real-time bran removal, the milling conditions are made stable and controllable, effectively reducing the broken rice rate and improving the quality and processing efficiency of finished rice.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] This invention discloses an automatic pressure adjustment device for a rice milling machine with a low broken rice rate. The device includes a frame, on which are horizontally arranged milling rollers, a whitening chamber covering the milling rollers, a screen surrounding the milling rollers and capable of radial sliding, a drive frame, a pressure adjustment unit, a temperature detection module, a low-temperature heat dissipation module, a central control module, a shell extraction device, and a discharge hopper. The milling rollers and the whitening chamber are coaxially arranged, with the screen positioned between them, forming an annular grinding gap suitable for rice whitening operations. The pressure adjustment unit abuts against the screen, providing power for the radial sliding of the screen and achieving precise control of the grinding pressure. The temperature detection module is fixed inside the whitening chamber to collect the internal temperature in real time. The low-temperature heat dissipation module is divided into two parts: one part is attached to the outer side wall of the whitening chamber, and the other part is inserted into the inner cavity of the milling roller. This enables synchronous heat dissipation inside and outside the core milling area, keeping the internal temperature of the whitening chamber within a safe threshold and preventing the rice grains from cracking due to high temperature. The central control module is electrically connected to the pressure regulating unit, the temperature detection module, and the low-temperature heat dissipation module. It receives real-time detection signals and issues control commands to form a fully automatic closed-loop control. The shell extraction device is connected to the bottom of the whitening chamber to extract the bran powder generated during milling in real time, preventing the bran powder from accumulating and compressing the rice grains. The discharge hopper is fixed at the bottom of the end of the whitening chamber to receive the finished whitened rice and guide it out smoothly. Furthermore, the screen is designed as two symmetrical semi-circular split structures, which, when assembled, form a complete ring and are arranged coaxially with the grinding roller, adapting to the shape of the grinding roller and the requirements of the whitening operation. The split structure facilitates disassembly, maintenance, and fine-tuning of the gap. The drive frame is horizontally fixed on the pressure adjustment unit, and its end face is arc-shaped and closely abuts against the screen surface. Its arrangement direction is perpendicular to the axis of the grinding roller, providing precise guidance and support for the radial sliding of the screen, preventing deflection and misalignment during the screen sliding process, and ensuring uniform grinding gap. The shell extraction device includes a shell extraction fan and a connecting pipe. One end of the connecting pipe is connected to the bottom of the whitening chamber, and the other end is connected to the shell extraction fan. The shell extraction fan is electrically connected to the central control module to realize linkage start and stop, and the bran powder is extracted through negative pressure throughout the process. Furthermore, the pressure regulating unit includes a servo motor, a ball screw drive pair, a screen mounting bracket, and a pressure sensor. The servo motor is fixedly mounted on the frame, and its output end is rigidly connected coaxially to the ball screw drive pair to achieve precise power transmission. The movable end of the ball screw drive pair, away from the servo motor, is fixedly connected to the screen mounting bracket. The servo motor drives the ball screw drive pair to rotate, causing the screen mounting bracket and the screen to move radially and directionally synchronously, thus finely adjusting the grinding gap. The pressure sensor is fixedly located on the side of the screen mounting bracket, with one end directly abutting the screen surface. It is also electrically connected to the central control module to collect the grinding pressure signal borne by the screen in real time and transmit it to the central control module, providing accurate data support for closed-loop pressure control. Furthermore, an elastic rubber buffer sheet is provided at the joint of the two semi-circular screens. The buffer sheet fits perfectly against the joint end face of the screens and is fixed by high-temperature resistant and environmentally friendly adhesive, with no loose gaps. The buffer sheet is made of highly elastic, wear-resistant, and high-temperature resistant elastic rubber material, which can not only fill the gap between the screens and prevent material leakage or rice grains from getting stuck in the joint, but also effectively buffer the instantaneous impact load of rice grains on the screens during the grinding process, reduce the impact of equipment vibration on the screens, avoid deformation and displacement of the screens due to impact, stabilize the grinding gap, and reduce rice grain breakage caused by sudden pressure changes. Furthermore, the temperature detection module includes multiple sets of temperature sensors. The temperature sensors are mounted on the inner side wall of the whitening chamber via mounting brackets. The mounting brackets are detachably connected to the whitening chamber via fastening bolts, facilitating disassembly, maintenance, and sensor calibration. The multiple sets of temperature sensors are evenly distributed to comprehensively collect the temperature of different areas inside the whitening chamber, avoiding single-point detection errors and improving the accuracy of temperature data. Furthermore, the low-temperature heat dissipation module includes a guide shaft, a rotary joint, a bracket, an inlet pipe, and an outlet pipe. The guide shaft is coaxially inserted into the internal cavity of the roller and rotates synchronously with the roller. An internal circulation channel is provided for the cooling medium to flow, directly carrying away the core heat generated by the rotational friction of the roller. The rotary joint is sealed at both ends of the guide shaft to achieve a sealed connection between the rotating parts and the fixed pipeline, preventing leakage of the cooling medium. The rotary joint is fixed to the frame by the bracket to maintain a stable position. The water inlet port of the rotary joint is connected to the water inlet pipe, and the water outlet port is connected to the water outlet pipe, forming a complete circulation heat dissipation path. Combined with the heat dissipation structure outside the whitening machine, it achieves dual internal and external heat dissipation. Furthermore, the central control module includes a PLC controller, a human-machine interface unit, and a drive unit. The human-machine interface unit includes a touch screen and an emergency stop button. The touch screen is used to preset the safe grinding temperature threshold and the optimal grinding pressure range, while simultaneously displaying equipment operating parameters, temperature, and pressure data in real time. The emergency stop button is used for emergency shutdown in case of sudden events to ensure equipment and operational safety. The drive unit includes a servo driver, which is connected to the servo motor control of the pressure regulation unit. It receives commands from the PLC controller and precisely drives the servo motor to rotate forward, reverse, or stop, thereby achieving dynamic fine-tuning of the grinding pressure.

[0008] This invention also discloses an adjustment method for the automatic pressure adjustment device of the aforementioned low broken rice rice milling machine, specifically including the following steps: The first step is system pre-debugging: Through the human-machine interaction unit of the central control module, the safe temperature threshold and optimal milling pressure range inside the whitening chamber are preset according to the rice variety, moisture content and processing precision, and the whole system is initialized. At the same time, the temperature sensor of the temperature detection module and the pressure sensor of the pressure regulation unit are zero-point calibrated to eliminate hardware detection errors and ensure accurate data acquisition in the future. The second step is real-time data acquisition: When the equipment starts up, it enters continuous grinding mode. The raw rice is fed into the whitening chamber at a uniform speed, and the rollers rotate at high speed to complete the whitening operation. At the same time, the temperature sensor collects the temperature data inside the whitening chamber in real time, and the pressure sensor collects the grinding pressure data borne by the screen in real time. After the two sets of data are filtered and noise reduced, they are synchronously transmitted to the PLC controller of the central control module. The third step is closed-loop linkage control: After receiving real-time temperature and pressure data, the PLC controller quickly compares and analyzes them with preset parameters, and issues control commands based on the analysis results. If the real-time pressure exceeds the preset range, the PLC controller controls the servo motor of the pressure regulating unit through the drive unit, which drives the ball screw drive pair, the screen mounting bracket, and the screen to slide directionally along the drive frame, precisely adjusting the grinding gap until the grinding pressure returns to the preset optimal range. If the real-time temperature approaches the preset safety threshold, the low-temperature heat dissipation module is immediately activated, and the cooling medium continuously circulates through the circulation channel to quickly reduce the internal temperature of the grinding chamber, maintaining a low-temperature and stable grinding condition throughout the process. The fourth step is the removal of bran and discharge: During the entire milling process, the central control module simultaneously starts the hulling fan of the hulling device, which forms a stable negative pressure through the connecting pipe to extract the bran powder generated inside the whitening chamber in real time, preventing the bran powder from accumulating and compressing the rice grains; after the rice whitening precision reaches the standard, the finished rice falls smoothly into the discharge hopper along the end channel of the whitening chamber, and is discharged through the discharge hopper, completing the complete low broken rice rate rice milling process.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Significantly reduced broken rice rate: The real-time pressure closed-loop adjustment technology dynamically adjusts the milling gap and pressure according to the working conditions to avoid excessive squeezing and friction that causes rice grains to break. Combined with a low-temperature milling environment, it reduces rice grain breakage and damage from both pressure and temperature perspectives, significantly reducing the broken rice rate and improving the finished rice yield and appearance quality. 2. Highly efficient and stable temperature control: The dual low-temperature rise structure of internal water cooling and external auxiliary heat dissipation of the rollers quickly and continuously removes the grinding heat, eliminating the problem of excessive temperature rise during whitening. It is suitable for long-term continuous industrial processing conditions, and the stability of equipment operation is greatly improved. 3. High level of intelligence: The central control module realizes the full-process automated linkage control of temperature monitoring, pressure regulation, heat dissipation and material discharge, eliminating the need for manual operation and repeated debugging. After parameter preset, it can run autonomously, simplifying the operation process, adapting to large-scale grain processing production lines and improving processing efficiency. 4. Durable structure and easy maintenance: The screen adopts a split splicing design, combined with elastic buffer plates to reduce rigid wear. The drive frame ensures stable and accurate displacement. The overall structure is compact and reasonable. Each module is easy to disassemble and maintain, and the equipment has a longer service life. Attached Figure Description

[0010] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is the front view of the present invention; Figure 3 This is a side view of the present invention; Figure 4 This is a cross-sectional structural diagram of the present invention; Figure 5 This is a schematic diagram of the pressure regulating unit of the present invention; Figure 6 This is a schematic diagram of the structure of the sieve of the present invention; In the diagram: 1. Frame; 2. Pressure regulating unit; 3. Temperature detection module; 4. Low temperature rise heat dissipation module; 5. Central control module; 6. Shell extraction device; 7. Discharge hopper; 11. Grinding roller; 12. Whitening chamber; 13. Screen; 14. Drive frame; 21. Servo motor; 22. Ball screw drive pair; 23. Screen mounting bracket; 24. Pressure sensor; 31. Temperature sensor; 32. Fixing base; 41. Guide shaft; 42. Rotary joint; 43. Bracket; 44. Water inlet pipe; 45. Water outlet pipe; 51. PLC controller; 52. Human-machine interface unit; 53. Drive unit; 61. Shell extraction fan; 62. Connecting pipe; 132. Buffer plate. Detailed Implementation

[0011] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0012] In the attached diagram, all identical reference numerals refer to the same components.

[0013] Example 1 This embodiment fully discloses the overall assembly structure, specific connection relationship of each component, structural form, material selection, size adaptation and corresponding function of the low broken rice rate rice milling machine pressure automatic adjustment equipment. The whole machine takes the frame 1 as the core support base. The frame 1 adopts a high-strength rigid frame structure welded from thickened square steel. Anti-slip and shock-absorbing pads are added to the bottom, which has sufficient structural strength and vibration resistance stability. It undertakes the bearing and fixing tasks of all components of the whole machine, effectively isolates the vibration transmission generated by the operation of the equipment, avoids the overall displacement and shaking during the operation of the equipment, and ensures that the milling operation is stable and orderly throughout the process. The side of the frame 1 is reserved with a standardized installation position to facilitate the rapid assembly and subsequent inspection and maintenance of electrical control components such as the pressure adjustment unit 2 and the central control module 5.

[0014] The core structure of the rice milling system includes horizontally arranged milling rollers 11, a whitening chamber 12, a screen 13, and a drive frame 14. The milling rollers 11 are horizontally arranged and are solid cylindrical rollers with spiral wear-resistant whitening ribs on their surface. The rollers are made of high-hardness alloy steel through precision machining and have a polished and hardened surface, resulting in excellent wear resistance and a long service life. The milling rollers 11 are rotatably mounted on the frame 1 via high-precision bearing seats and are driven by an external frequency converter motor coaxially connected through a coupling. The rotation speed can be adjusted according to processing requirements, providing stable and efficient whitening of rice. Uniform core power; the whitening chamber 12 is a closed stainless steel cavity structure, coaxially wrapped around the outside of the grinding roller 11. The two are strictly coaxially arranged, and the coaxiality error is controlled within 0.05mm. This ensures that the annular grinding gap is uniform throughout the rotation of the grinding roller 11, without local uneven grinding or uneven force. The top of the whitening chamber 12 is reserved with a funnel-shaped feed port to facilitate the uniform and smooth feeding of raw rice. The bottom is correspondingly opened with a long strip-shaped bran powder discharge port. The aperture is adapted to the bran powder discharge requirements, while preventing rice grains from falling and ensuring smooth two-way feeding of raw materials and discharge of bran powder.

[0015] The screen 13 adopts a symmetrical semi-circular split structure. Each screen piece is made of 304 stainless steel sheet by stamping, which has high structural strength, corrosion resistance and is not easily deformed. After being spliced, it forms a complete ring and is set around the outside of the grinding roller 11, in the gap area between the grinding roller 11 and the whitening chamber 12. The mesh diameter of the screen 13 is uniformly set at 1.2mm-1.5mm, which is precisely adapted to the rice milling bran powder separation requirements. It can smoothly pass through fine bran powder, while effectively blocking whole rice grains from passing through, avoiding rice grains from being discharged with bran powder and causing raw material loss. At the splicing joint of the two semi-circular screens 13, there is an elastic rubber buffer 132. The buffer 132 is made of highly elastic, highly wear-resistant and high-temperature resistant fluororubber material, and the thickness is controlled at 2mm. -3mm, the width perfectly matches the side thickness of the screen 13, sealing the splicing gaps to prevent rice grains from getting stuck and leaking, while also buffering the impact of rice grains and equipment vibration, preventing the screen 13 from deforming and shifting. It is evenly bonded and fixed with food-grade high-temperature resistant and environmentally friendly adhesive, with no loose gaps or curling edges after bonding. It not only tightly fills the splicing gaps of the screen 13 to prevent rice grains from getting stuck and breaking, but also avoids the problem of material leakage. It can also effectively buffer the instantaneous impact load generated by the high-speed impact of rice grains on the screen 13 during the grinding process, greatly reducing the direct transmission of equipment vibration to the screen 13, preventing the screen 13 from undergoing plastic deformation and position shift due to repeated impacts, and always stabilizing the grinding gap, thereby reducing the rice grain crushing caused by sudden pressure changes and uneven gaps from the root. The drive frame 14 is horizontally fixed to the top of the pressure regulating unit 2. It is made of hard aluminum alloy and the end face is an arc that perfectly matches the curvature of the outer wall of the screen 13. It fits tightly against the outer wall of the screen 13. The layout direction is perpendicular to the axis of the grinding roller 11. The surface of the drive frame 14 is smooth and polished to reduce the frictional resistance during the sliding process of the screen 13. It provides precise guidance and rigid support for the radial directional sliding of the screen 13, prevents circumferential deflection and misalignment of the screen 13 during the sliding process, and ensures that the grinding gap is uniform throughout the process.

[0016] The pressure regulating unit 2, as the core automatic pressure control component of the entire machine, features high overall assembly precision and fast response speed. It includes a servo motor 21, a ball screw drive pair 22, a screen mounting bracket 23, and a pressure sensor 24. The servo motor 21 is a high-precision closed-loop servo motor, fixedly mounted on a pre-set mounting position on the side of the frame 1 and connected by bolts. Horizontal calibration is performed during installation. The output end is rigidly connected to the ball screw drive pair 22 via a rigid coupling, ensuring lossless and lag-free power transmission. It enables precise forward and reverse speed adjustment with high positioning accuracy, preventing slippage and idle running. The ball screw drive pair 22 uses a precision-ground ball screw with small transmission clearance and smooth operation. Its movable end, away from the servo motor 21, is firmly welded to the bottom of the screen mounting bracket 23, with the weld joint reinforced. The screen 13 is reinforced and fixed to the upper end of the screen mounting bracket 23 by fastening bolts. It moves radially in sync with the screen mounting bracket 23 to precisely adjust the grinding gap, with an adjustment accuracy of up to 0.1mm. The pressure sensor 24 is a high-precision thin-film pressure sensor, which is fixedly installed on the side of the screen mounting bracket 23 near the screen 13. The installation position avoids the vibration interference area, and the detection end directly abuts against the outer surface of the screen 13. It collects the dynamic pressure value of the screen 13 during the grinding process in real time, converts the physical pressure signal into a standard electrical signal, and transmits it to the central control module 5 in real time to form continuous pressure data feedback. With the buffering and stabilizing effect of the buffer plate 132, the grinding pressure is kept stable and precisely controlled throughout the process, and the problem of sudden pressure rise and fall is eliminated.

[0017] The temperature detection module 3 includes three sets of evenly distributed temperature sensors 31. The temperature sensors 31 are high-precision platinum resistance thermometers, which are accurate in temperature measurement and have a fast response speed. They are evenly installed on the inner wall of the whitening chamber 12 through insulating mounting bases 32, and are respectively distributed in the three core areas of the whitening chamber 12: the front end, the middle end and the rear end. This avoids the direct impact position of the material. The temperature data inside the whitening chamber 12 is collected synchronously from multiple points, which fully covers the grinding area and avoids single-point detection errors. The temperature measurement data is accurate and comprehensive. The mounting bases 32 are made of insulating high-temperature resistant plastic material and are detachably connected to the whitening chamber 12 by fastening bolts. The temperature sensors 31 can be maintained, replaced and zero-point calibrated without disassembling the whole machine, which is convenient. The low-temperature heat dissipation module 4 adopts a dual internal and external heat dissipation structure to specifically solve the heat generation problem in the core grinding area. The main guide shaft 41 is a hollow stainless steel shaft that coaxially passes through the internal cavity of the grinding roller 11. A spiral circulation guide channel is opened inside the shaft to extend the flow path of the cooling medium and improve heat dissipation efficiency. The rotary joint 42 adopts a high-pressure sealed rotary joint, which is sealed at both ends of the main guide shaft 41 to achieve a seamless sealing connection between the rotating parts and the fixed pipeline, preventing the leakage of cooling medium. The rotary joint 42 is fixed on the frame 1 by a special bracket 43, and its position is fixed and does not shake. It is connected to the water inlet pipe 44 and the water outlet pipe 45 respectively. The water inlet pipe 44 is connected to a cooling water circulation device, and the cooling medium continuously circulates, directly carrying away the core heat generated by the rotation friction of the grinding roller 11. With the heat dissipation fin structure attached to the outer wall of the whitening chamber 12, heat dissipation is carried out simultaneously inside and outside, which quickly reduces the overall temperature of the grinding area and stabilizes the internal temperature of the whitening chamber 12 within a safe range below 40°C, completely avoiding problems such as rice grains bursting, cracking, and burning due to high temperature.

[0018] The central control module 5 is integrated inside the electrical control box, including a PLC controller 51, a human-machine interface unit 52, and a drive unit 53. The PLC controller 51 can adjust the speed of the variable frequency drive motor according to the grinding pressure and temperature. The PLC controller 51 can precisely adjust the speed of the variable frequency drive motor according to the grinding pressure and temperature. When the grinding pressure exceeds the upper limit of the preset range, the speed will automatically decrease by 5% to 10% to reduce the friction intensity between the grinding roller 11 and the rice grains. When the temperature of the whitening chamber 12 approaches the 40℃ safety threshold, the speed will automatically decrease by 8% to 15% to reduce friction heat generation from the source, thereby achieving coordinated adjustment of grinding intensity, pressure, and temperature. The central control module 5 coordinates the operation of all electrical control components of the machine, achieving fully automatic closed-loop control without the need for real-time manual monitoring. Operators can preset parameters such as grinding temperature threshold, grinding pressure range, and feeding rate through the touch screen of the human-machine interaction unit 52. The emergency stop button is located on the side of the touch screen for easy emergency shutdown in case of emergencies, ensuring equipment and operational safety. The PLC controller 51 adopts an industrial-grade programmable logic controller with fast computing speed and strong anti-interference ability. It can quickly process temperature and pressure detection data and issue control commands in real time. The drive unit 53 has a built-in dedicated servo driver, which is connected to the servo motor 21 of the pressure adjustment unit 2. It accurately receives commands from the PLC controller 51 and quickly drives the servo motor 21 to rotate forward, reverse, or stop, achieving millisecond-level dynamic fine adjustment of grinding pressure. The shelling device 6 uses a high-pressure negative pressure fan 61, which is connected to the bran powder outlet at the bottom of the whitening chamber 12 through the connecting pipe 62. It maintains a stable negative pressure throughout the process, and promptly extracts the bran powder generated during grinding, preventing the bran powder from accumulating and compressing the rice grains inside the whitening chamber 12. The discharge hopper 7 is fixed at the bottom end of the whitening chamber 12 and adopts an inclined guide structure with an inclination angle controlled between 30° and 45°. This angle has been verified by experiments to ensure that the finished rice can fall smoothly without bumping, avoiding rice accumulation due to an angle that is too small, and preventing secondary breakage due to an angle that is too large, thus ensuring the integrity of the finished product.

[0019] The equipment in this embodiment has been verified through actual large-scale processing. It uses conventional japonica rice with a moisture content of approximately 14% as the raw material, sets a standard feeding rate of 500 kg / h, and presets the safe temperature threshold of the whitening chamber 12 to 40℃ via the human-machine interface unit 52. The optimal grinding pressure range is 0.15 MPa-0.2 MPa. The equipment runs continuously for 8 hours without interruption, operating smoothly throughout without abnormal vibration, jamming, cooling medium leakage, or bran powder blockage. The buffer plate 132 effectively offsets the high-speed impact of rice grains and the vibration of the equipment operation. The screen 13 exhibits no plastic deformation or positional shift throughout the process, and the grinding pressure fluctuation range is controlled within ± Within 0.02MPa, the internal temperature of the whitening chamber 12 is stably maintained at 35℃-38℃, with no local overheating or rice grain cracking. The final broken rice rate is stably controlled within 2.0%, which is 18% lower than that of the same specification equipment without buffer plate 132. Compared with traditional rice milling equipment, the overall broken rice rate is reduced by more than 70%. The finished rice has extremely high integrity, with no damage or cracking. The rice yield is 9% higher than that of traditional equipment. The processing quality fully meets the national high-quality rice processing standards. The equipment has excellent stability and durability during continuous operation and can meet the long-term continuous processing needs of large-scale rice processing plants.

[0020] Example 2 This embodiment, based on the complete equipment structure described in Embodiment 1, details the entire process of the automatic adjustment method for low broken rice milling pressure, including the precise linkage logic of each component, parameter control details, and measured results for processing various rice varieties. The entire process relies on the central control module 5 to achieve automated and coordinated control of the four core aspects: pressure, temperature, heat dissipation, and bran removal. This eliminates the need for real-time manual intervention, significantly reducing the intensity of manual operation and avoiding errors from manual adjustments. The specific implementation steps, linkage logic, and measured results are as follows: The first step is system pre-debugging and parameter calibration. Before the equipment starts formal processing, the operator first checks the assembly firmness of the whole machine components, the sealing of the pipeline connections, and the standardization of the circuit wiring. After confirming that there are no abnormalities, the power is turned on. Then, through the touch screen of the human-machine interaction unit 52, the operator can accurately preset the corresponding core parameters such as the safe temperature threshold of the whitening chamber 12, the optimal milling pressure range, and the feeding rate, according to the rice variety to be processed (japonica rice, indica rice, glutinous rice), the plumpness of the grains, the moisture content, and the target processing precision. Different parameters are adapted for different varieties of rice. Japonica rice has high grain hardness and dense structure, and is suitable for the medium-high pressure range of 0.15 MPa to 0.2 MPa; indica rice has slender grains and medium hardness, and is suitable for the medium pressure range of 0.12 MPa to 0.18 MPa; glutinous rice has soft and glutinous grains and low hardness, and is suitable for the range of 0.1 MPa to 0.15 MPa. The low-pressure range and pressure range are both optimized and determined based on rice grain compressive strength tests and actual grinding effects, with the temperature threshold uniformly set at 40℃. After the parameters are entered, the PLC controller 51 automatically controls the entire machine to complete the initialization self-test, checking the operating status of the pressure regulating unit 2, low-temperature heat dissipation module 4, shell extraction device 6, and temperature detection module 3 one by one to ensure that all components are in normal standby state and there are no fault alarms. Subsequently, the system automatically starts the calibration program to perform zero-point calibration and range calibration on the temperature sensor 31 and pressure sensor 24 to eliminate hardware detection errors. After calibration, the system prompts that it is ready, laying a solid foundation for subsequent precise closed-loop control.

[0021] The second step is real-time data acquisition and transmission. After initialization and calibration, the equipment starts and enters continuous grinding mode. Raw rice is fed into the whitening chamber 12 at a constant speed through the feed hopper. The feeding rate is kept stable to avoid fluctuations in the working conditions caused by sudden changes in feeding speed. The grinding roller 11 rotates at a constant speed under the drive of the variable frequency motor, and works with the screen 13 to gently whiten the rice grains. At the same time, the three sets of temperature sensors 31 of the temperature detection module 3 synchronously collect the temperature data of the front, middle and rear ends of the whitening chamber 12 in real time, and take the average value as the real-time temperature value. The pressure sensor 24 collects the dynamic grinding pressure data of the screen 13 in real time. The two sets of data are processed by the filter and noise reduction module built into the central control module 5 to effectively remove the noise signals generated by equipment vibration and electromagnetic interference, ensuring that the data is true and accurate. The processed temperature and pressure data are synchronously transmitted to the PLC controller 51 in real time through the communication line, providing reliable data support for subsequent closed-loop control. The data transmission delay does not exceed 50ms, realizing real-time monitoring of the working conditions.

[0022] The third step is closed-loop linkage for precise control. After receiving real-time temperature and pressure data, the PLC controller 51 immediately performs a rapid comparison and analysis with preset parameters, determining in milliseconds whether the current grinding conditions meet the standards. It then precisely issues corresponding control commands to achieve coordinated control of pressure and temperature. If the real-time pressure exceeds the preset range, and the pressure is too high, the PLC controller 51 sends a command to the drive unit 53 to control the servo motor 21 to rotate forward. This, through the ball screw drive pair 22, drives the screen mounting bracket 23 and the screen 13 to smoothly slide outward radially along the drive frame 14, slowly widening the grinding gap and reducing the grinding pressure. If the pressure is too low, the servo motor 21 is controlled to rotate in reverse, driving the screen 13 to slide inward, narrowing the grinding gap. The grinding pressure is increased, and the buffer plate 132 simultaneously plays a buffering role to offset the minor vibrations during the sliding process and the instantaneous impact of grinding, suppressing pressure fluctuations until the grinding pressure quickly returns to the preset optimal range. If the real-time temperature approaches the preset safety threshold, the PLC controller 51 immediately activates the low-temperature heat dissipation module 4, and the cooling water circulation device is started. The cooling medium flows into the guide shaft 41 through the water inlet pipe 44, circulates through the circulation channel, and is discharged from the water outlet pipe 45, continuously removing the core heat. In conjunction with the external heat dissipation structure, the temperature drops rapidly. After the temperature drops back to the safe range, low-power circulation heat dissipation is maintained, maintaining a low-temperature, stable, and uniform grinding condition throughout the process to ensure the quality of rice grain whitening.

[0023] The fourth step is continuous desiccation and stable discharge. Throughout the entire grinding process, the central control module 5 continuously controls the extraction fan 61 to maintain high-speed operation, creating a stable negative pressure at the bottom of the whitening chamber 12 through the connecting pipe 62. The negative pressure value of the extraction fan 61 is set to -0.02 MPa, a value that has been verified through testing to quickly extract particles with a diameter of 0.1 mm to 1.0 mm. The rice milling process avoids excessive negative pressure that could cause rice grains to be pulled out and resulting in raw material loss. The rice bran powder generated in the milling chamber 12 is quickly extracted in real time and collected into a storage bin via a dedicated pipeline. This prevents the rice bran powder from accumulating inside the milling chamber 12 and compressing the rice grains, reducing additional frictional loss and preventing the rice bran powder from adhering to the screen 13 and clogging the mesh. Once the rice milling precision meets the standard, the finished rice falls smoothly into the discharge hopper 7 along the inclined channel at the end of the milling chamber 12. It is then slowly discharged through the discharge hopper 7 and directly collected into the finished product bin. The entire process is free from impact and compression, preserving the complete shape of the rice grains and completing the low-broken-rice milling process. After processing, the equipment can be stopped with a single button, and the system automatically shuts down all components, completing a single processing cycle.

[0024] This embodiment, combined with an optimized overall machine structure, has been tested in batch processing of multiple rice varieties. Using three mainstream rice raw materials—japonica rice, indica rice, and glutinous rice—and correspondingly adapted to different processing parameters, the equipment can quickly adapt and operate fully automatically without frequent manual parameter adjustments. The buffer plate 132 effectively avoids sudden pressure changes and screen vibration shift during the milling process. The broken rice rate after processing of the three types of rice is controlled within 2.0%, 2.8%, and 3.0%, respectively, all far lower than the traditional rice milling equipment's broken rice rate standard of over 7%. The processing efficiency is 35% higher than traditional equipment. After 12 hours of continuous operation, there are no problems such as pressure imbalance, temperature exceeding limits, bran accumulation, or screen blockage. The screen 13 exhibits no impact deformation or positional shift, ensuring stable and reliable equipment operation. It is suitable for large-scale, continuous, and refined processing of different rice varieties. Its practicality and versatility fully meet the high-standard processing requirements of the grain processing industry, possessing extremely high value for promotion and application.

[0025] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An automatic pressure adjustment device for a rice milling machine with low broken rice rate, characterized in that, The machine includes a frame (1), on which are arranged horizontally arranged grinding rollers (11), a whitening chamber (12) covering the grinding rollers (11), a screen (13) surrounding the grinding rollers (11) and capable of radial sliding, a drive frame (14), a pressure regulating unit (2), a temperature detection module (3), a low temperature rise heat dissipation module (4), a central control module (5), a shell extraction device (6), and a discharge hopper (7); the grinding rollers (11) and the whitening chamber (12) are coaxially arranged, and the screen (13) is located between them; the grinding rollers (11) are connected to an external variable frequency drive motor through a coupling. The frequency drive motor is electrically connected to the central control module (5); the pressure regulating unit (2) abuts against the screen (13); the temperature detection module (3) is located inside the whitening chamber (12); the low temperature rise heat dissipation module (4) includes a heat dissipation structure that fits against the outside of the whitening chamber (12) and a flow guiding heat dissipation structure that passes through the inner cavity of the roller (11); the central control module (5) is electrically connected to the pressure regulating unit (2), the temperature detection module (3), and the low temperature rise heat dissipation module (4) respectively; the shell extraction device (6) is connected to the bottom of the whitening chamber (12); and the discharge hopper (7) is located at the bottom of the end of the whitening chamber (12).

2. The device according to claim 1, characterized in that, The screen (13) is configured as two symmetrical semi-circular split structures, which are assembled into a ring and arranged coaxially with the grinding roller (11); the drive frame (14) is horizontally fixed on the pressure regulating unit (2), its end face is arc-shaped and abuts against the surface of the screen (13), and its arrangement direction is perpendicular to the axis of the grinding roller (11); the shell extraction device (6) includes a shell extraction fan (61) and a connecting pipe (62), one end of the connecting pipe (62) is connected to the bottom of the whitening chamber (12), and the other end is connected to the shell extraction fan (61), and the shell extraction fan (61) is electrically connected to the central control module (5).

3. The device according to claim 2, characterized in that, The pressure regulating unit (2) includes a servo motor (21), a ball screw drive pair (22), a screen mounting bracket (23), and a pressure sensor (24). The servo motor (21) is fixed to the frame (1), and its output end is coaxially connected to the ball screw drive pair (22). The movable end of the ball screw drive pair (22) away from the servo motor (21) is fixed to the screen mounting bracket (23). The pressure sensor (24) is located on the side of the screen mounting bracket (23), and one end abuts against the surface of the screen (13) and is electrically connected to the central control module (5).

4. The device according to claim 3, characterized in that, An elastic rubber buffer sheet (132) is provided at the splicing joint of the two semi-circular screens (13). The buffer sheet (132) fits into the splicing end face and is fixed by high temperature resistant adhesive.

5. The device according to claim 2, characterized in that, The temperature detection module (3) includes multiple temperature sensors (31). The temperature sensors (31) are installed on the inner wall of the whitening chamber (12) via a fixing seat (32). The fixing seat (32) is detachably connected to the whitening chamber (12) via fastening bolts.

6. The device according to claim 2, characterized in that, The low-temperature heat dissipation module (4) includes a guide shaft (41), a rotary joint (42), a bracket (43), a water inlet pipe (44), and a water outlet pipe (45). The guide shaft (41) is coaxially inserted into the internal cavity of the roller (11). The rotary joint (42) is sealed and assembled at both ends of the guide shaft (41). The rotary joint (42) is fixed to the frame (1) by the bracket (43). The water inlet port of the rotary joint (42) is connected to the water inlet pipe (44), and the water outlet port is connected to the water outlet pipe (45). A circulation guide channel is opened inside the guide shaft (41). The cooling medium forms a circulation path through the water inlet pipe (44), the guide shaft (41), and the water outlet pipe (45) to realize the core heat dissipation of the roller (11).

7. The device according to claim 1, characterized in that, The central control module (5) includes a PLC controller (51), a human-machine interaction unit (52), and a drive unit (53); the human-machine interaction unit (52) includes a touch screen and an emergency stop button, the drive unit (53) includes a servo driver, and the drive unit (53) is controlled and connected to the servo motor (21) of the pressure regulating unit (2).

8. A method for adjusting the device according to any one of claims 1 to 7, characterized in that, The process includes the following steps: First, the temperature threshold and grinding pressure range are preset by the central control module (5) to complete the system initialization and simultaneously calibrate the temperature sensor (31) and pressure sensor (24); Second, after the equipment is running, the temperature sensor (31) and pressure sensor (24) collect the internal temperature and grinding pressure data of the whitening chamber (12) in real time, and transmit them to the PLC controller (51) after filtering; Third, the PLC controller (51) processes the data, controls the pressure adjustment unit (2) to drive the screen (13) to slide along the drive frame (14) to adjust the grinding gap, and simultaneously starts the low temperature rise heat dissipation module (4); Fourth, the shell extraction fan (61) is started during the grinding process, and after the grinding is completed, the finished rice is discharged through the discharge hopper (7).

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