Multi-stage circulating heat exchange drying tower structure for grain dryer

Abstract

The application belongs to the technical field of drying tower and specifically discloses a multi-stage circulating heat exchange drying tower structure for a grain dryer, which comprises a grain turning bin, a feeding bin, a side-mounted rack table, a spiral material pushing machine, a rotary material turning unit and an elevator, the spiral material pushing machine is installed in the grain turning bin, a plurality of drying bins that are sequentially communicated are installed in the upper part of the grain turning bin, the feeding bin is installed above the drying bin close to the upper part, the elevator is connected with the feeding bin through a communicating pipe, a drying and shunting unit is arranged in the drying bin, the multi-stage structure of adjustable shunting, active pressurization, Venturi injection and wall-adhesion flow guiding is used to realize dynamic distribution and uniform distribution of air volume, significantly improve the contact efficiency of air flow and heat exchange wall surface, solve the problems of air flow concentration, uneven air volume distribution and low heat exchange efficiency of the existing equipment, and has the advantages of good drying uniformity and high thermal efficiency.

Description

Technical Field

[0001] This invention belongs to the field of drying tower technology, and specifically discloses a multi-stage circulating heat exchange drying tower structure for grain dryers. Background Technology

[0002] Grain drying is a crucial step in post-harvest grain processing, directly impacting grain storage safety and processing quality. Currently, circulating drying towers are widely used in drying operations for major grain varieties such as rice, corn, and wheat due to their advantages of good drying uniformity, low breakage rate, and relatively controllable energy consumption.

[0003] Existing circulating drying towers typically include a tower body, an elevator, distribution channels, a fan, and a heat source system. The working process is as follows: the elevator lifts the grain to be dried from the bottom to the top of the tower body. Under gravity, the grain flows downwards through multiple distribution channels within the tower body. Simultaneously, the fan introduces hot air from an external heat source into the tower. The hot air comes into direct or indirect contact with the grain in the distribution channels, achieving heat exchange and removing moisture from the grain. The dried grain is discharged from the bottom of the tower, completing one cycle, or undergoing multiple cycles until a safe moisture content is reached.

[0004] In practical applications, the airflow organization method of existing circulating drying towers has the following technical defects: the air outlet of the existing equipment is usually set on one side or in the center of the tower body, and the airflow is concentrated in one place, forming a "wind column" effect. The grain near the air outlet receives a large amount of air and dries quickly, while the grain far from the air outlet receives a small amount of air and dries slowly, resulting in uneven radial drying of the tower body. Some grains are over-dried or even scorched, while some grains are under-dried, affecting the overall drying quality. To distribute airflow into multiple channels, some equipment uses baffles or diverter plates at the fan outlet to passively split a single airflow into multiple streams. However, baffle diversion is essentially a throttling method, resulting in significant local resistance losses and a substantial drop in fan pressure. The resulting airflow pressure is insufficient to overcome the flow resistance within the diverter channels, especially in the far-end channels where insufficient airflow often leads to poor drying. Furthermore, the fixed structure of the diverter plates prevents dynamic adjustment of the distribution ratio based on actual operating conditions (such as grain type, moisture content, and material layer height), resulting in poor adaptability.

[0005] In summary, existing circulating drying towers suffer from technical problems such as concentrated airflow, uneven air volume distribution, large energy loss, and low indirect heat exchange efficiency. There is an urgent need to develop a drying tower structure that can achieve uniform airflow distribution, on-demand air volume distribution, and high heat exchange efficiency. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the background art, and to propose a multi-stage circulating heat exchange drying tower structure for grain dryers, including a grain turning silo, a feeding silo, a side mounting platform, a screw pusher, a rotary turning unit, and an elevator. The screw pusher is installed inside the grain turning silo, and multiple sequentially connected drying chambers are installed above the grain turning silo. The feeding silo is installed above the uppermost drying chamber. The elevator is connected to the feeding silo through a connecting pipe at one end. A drying diversion unit is provided inside the drying chamber, and the side mounting platform is fixedly installed on the multiple drying chambers. On one side, a drying fan is fixedly installed above the side mounting platform and near the drying chamber. A fan compartment is provided between the drying fan and the drying chamber. An air-gathering pipe is connected to the air outlet of the drying fan inside the fan compartment. A diverter pipe is connected to both sides of the air-gathering pipe. An airflow guiding unit is provided inside the diverter pipe. A booster suction fan is connected to the end of the diverter pipe away from the air-gathering pipe. Side flow equalization units are provided at both ends of the air outlet pipe of the booster suction fan. The rotating turning unit is located inside the grain turning hopper and above to prevent the grain from falling and clogging.

[0007] In the above technical solution, the drying and diversion unit further includes multiple baffles fixedly installed on both sides inside the drying chamber. Heat exchange channels are opened at equal intervals along the horizontal direction inside the multiple baffles. Heat exchange plates are installed inside each heat exchange channel. A flow channel for grain to fall is provided between two adjacent sets of heat exchange plates. The fan chamber is sealed on one side outside the upper and lower sets of baffles. Ladders are fixedly installed on the outside of multiple drying chambers.

[0008] In the above technical solution, the airflow guiding unit further includes a storage box connected to the inside of the diversion pipe. A hydraulic cylinder is fixedly installed on one side of the storage box. A connecting rod is fixedly installed on the telescopic end of the hydraulic cylinder. A diversion arc plate is fixedly installed on one end of the connecting rod. An arc-shaped ramp is fixedly installed on the outer surface of one end of the diversion arc plate. One end of the diversion arc plate extends movably into the inside of the air gathering pipe to divert the airflow from the air gathering pipe to the diversion pipe.

[0009] In the above technical solution, the side flow air distribution unit further includes a Venturi tube ejector connected to one end of the air outlet pipe of the booster suction fan, and the end of the Venturi tube ejector away from the booster suction fan is connected to a drain pipe through a connecting unit.

[0010] In the above technical solution, the connecting unit further includes a vertical pipe connected to the end of the Venturi tube ejector that is away from the booster suction fan. The end of the vertical pipe away from the Venturi tube ejector is connected to a bend pipe, which is connected to the inside of the drainage pipe.

[0011] In the above technical solution, the inner wall of the drainage pipe is inclinedly provided with multiple sets of heating units, the drainage pipe is installed with drainage ventilation pipes at equal intervals along the horizontal direction inside the drainage pipe, and the drainage ventilation pipe is provided with an airflow extension unit inside the drainage ventilation pipe.

[0012] In the above technical solution, further, the multiple sets of heating units include mounting cylinder rods fixedly installed on the inner wall of the drainage pipe, one end of the mounting cylinder rod is fixedly installed with a heat spreader plate, and multiple guide plates are installed sequentially from top to bottom on the outer surface of the heat spreader plate.

[0013] In the above technical solution, the airflow extension unit further includes a rectangular tube connected to one end of the drainage ventilation pipe, and a V-shaped guide plate is fixedly installed on the outside of the end of the rectangular tube away from the drainage ventilation pipe.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention, by installing a concentrating air pipe inside the blower compartment and connecting diverting pipes on both sides of the concentrating air pipe, combined with a retractable and adjustable diverting arc plate in the airflow guiding unit, can actively and controllably divert the concentrated airflow from the blower outlet to both sides of the blower compartment. The diverted airflow is further distributed by the side-flow equalization unit, making the airflow distribution entering each drying compartment more uniform. This effectively eliminates the radial drying unevenness problem caused by the "wind column" effect in traditional equipment, avoids the phenomenon of local over-drying or under-drying of grain, and improves the overall drying quality.

[0015] 2. This invention abandons the passive flow diversion method using fixed baffles in traditional equipment, and instead employs a structure combining a Venturi tube ejector and a booster suction fan. The booster suction fan actively provides power compensation for the diverted airflow, while the Venturi tube ejector uses the jet principle to create a negative pressure zone in the pipeline, drawing in surrounding air into the main airflow, effectively doubling the air volume. This structure significantly reduces local resistance loss during the flow diversion process, ensuring sufficient airflow with adequate dynamic pressure even at the far end of the diversion channel, overcoming the problem of poor drying effect at the far end due to excessive pressure drop in traditional structures.

[0016] 3. This invention incorporates a heating unit on the inner wall of the drainage pipe, consisting of a mounting cylinder, a heat spreader plate, and multiple guide plates. This structure increases the contact area between the airflow and the heat exchange elements, guiding the airflow to fully exchange heat with the heat spreader plate and guide plates during its flow, efficiently transferring heat into the airflow, and allowing the hot airflow to enter the heat exchange channel at a stable temperature for heat exchange with the heat exchange plates. Simultaneously, by installing a V-shaped guide plate at the end of the drainage ventilation pipe, the airflow is guided as a wall-mounted jet, extending the residence time and contact path of the hot air on the wall of the distribution channel, significantly improving the convective heat transfer coefficient, ensuring full utilization of heat, and reducing heat loss.

[0017] 4. In this invention, the airflow guiding unit adopts a hydraulic cylinder-driven diversion arc plate structure, which can adjust the depth of the diversion arc plate extending into the air-gathering pipe in real time according to actual working conditions (such as different grain varieties, moisture content, or material layer height), thereby dynamically adjusting the air volume ratio entering the two diversion pipes. This design allows the equipment to flexibly cope with changing drying needs without the need for manual adjustment during shutdown, realizing on-demand air volume distribution and significantly improving the equipment's intelligence level and applicability.

[0018] 5. By setting up multiple sequentially connected drying chambers, and configuring an independent drying fan and a distribution and equalization system for each drying chamber, this invention constructs a multi-stage circulating heat exchange system. As the grain passes through the multiple drying chambers from top to bottom, it undergoes indirect heat exchange with the heat exchange plates in each chamber, gradually evaporating the moisture in the grain. This method allows for repeated heat exchange with the optimized hot airflow, achieving tiered drying. Combined with the rotating turning unit in the grain turning chamber, it effectively prevents congestion and bridging of the grain during flow, ensuring smooth material flow and further improving the overall drying efficiency and operational stability of the machine. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention from another angle; Figure 3 This is a schematic diagram of the internal structure of the drying chamber of the present invention. Figure 4 This is a schematic diagram of the connection structure between the baffle and the fan housing of the present invention; Figure 5 This is a schematic diagram of the connection structure between the fan compartment and the air-gathering duct of the present invention; Figure 6 This is a schematic diagram of the connection structure between the baffle and multiple sets of heat exchange plates in this invention; Figure 7 This is a schematic diagram of the connection structure between the drying fan and the air-collecting duct of the present invention; Figure 8 This is a schematic diagram of the internal structure of the side-flow equalization unit of the present invention; Figure 9 This is a schematic diagram of the connection structure between the heating unit and the drainage tube of the present invention; Figure 10 For the present invention Figure 9 Enlarged view of the structure at point A in the middle.

[0020] In the diagram: 1. Grain turning bin; 2. Feeding bin; 3. Side mounting platform; 4. Drying bin; 5. Screw conveyor; 6. Ladder; 7. Drying fan; 8. Fan compartment; 9. Connecting pipe; 10. Elevator; 11. Baffle; 12. Heat exchange plate; 13. Heat exchange channel; 14. Concentrating duct; 15. Drainage pipe; 16. Diverting pipe; 17. V-shaped guide plate; 18. Venturi tube ejector; 19. Drainage ventilation pipe; 20. Booster suction fan; 21. Hydraulic cylinder; 22. Arc-shaped ramp; 23. Diverting arc plate; 24. Connecting rod; 25. Bend; 26. Rectangular tube; 27. Mounting cylinder; 28. Guide plate; 29. ​​Heat spreader plate; 30. Rotary turning unit; 31. Vertical pipe; 32. Storage box. Detailed Implementation

[0021] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the invention is not limited to the specific embodiments disclosed below.

[0023] like Figures 1-10The multi-stage circulating heat exchange drying tower structure for a grain dryer shown includes a grain turning bin 1, a feeding bin 2, a side mounting platform 3, a screw conveyor 5, a rotary turning unit 30, and an elevator 10. The screw conveyor 5 is installed inside the grain turning bin 1 and is used to discharge the dried grain from the bottom of the grain turning bin 1. Multiple drying bins 4 are connected and installed in sequence above the grain turning bin 1. The multiple drying bins 4 are arranged in series from top to bottom to form a multi-stage drying channel. The feeding bin 2 is connected and installed above the drying bins 4 near the top. The elevator 10 is connected to the feeding bin 2 through a connecting pipe 9 at one end and is used to lift the grain to be dried to the top of the tower and feed it into the feeding bin 2. The drying bins 4 are equipped with... There is a drying and diversion unit to guide the grain to fall evenly in the silo and make full contact with the hot airflow. The side mounting platform 3 is fixedly installed on one side of multiple drying silos 4, and a drying fan 7 is fixedly installed above the side mounting platform 3 and correspondingly close to the drying silos 4. Each drying silo 4 is equipped with an independent drying fan 7 to achieve graded air supply and independent control. A fan chamber 8 is set between the drying fan 7 and the drying silo 4. A concentrator duct 14 is connected and installed inside the fan chamber 8 and near the air outlet of the drying fan 7. Diverter pipes 16 are connected and installed on both sides inside the concentrator duct 14. When working, the drying fan 7 starts and sends the hot air provided by the external heat source into the fan chamber 8. The hot air first enters the concentrator duct 14 for collection. The concentrating duct 14 serves to concentrate airflow and increase wind speed, providing a stable air source for subsequent diversion. The diversion duct 16 is equipped with an airflow guiding unit, which actively diverts the concentrated airflow in the concentrating duct 14 to the diversion ducts 16 on both sides, achieving initial dispersion of airflow and laying the foundation for subsequent uniform distribution to each drying chamber 4. A booster suction fan 20 is connected and installed inside the diversion duct 16 and at the end away from the concentrating duct 14. The booster suction fan 20 actively pressurizes the diverted airflow, compensates for the resistance loss along the pipeline, and ensures that the airflow has sufficient pressure to overcome the flow resistance of the subsequent pipeline, solving the problem of insufficient airflow in the far-end diversion channel in the traditional diversion structure. Side flow equalization units are set at both ends of the outlet duct of the booster suction fan 20. The side flow equalization units further evenly distribute the pressurized airflow, so that the airflow pressure entering each drying chamber 4 is balanced and the flow rate is consistent, thereby ensuring uniform drying effect of each drying chamber 4. The rotating turning unit 30 is set inside the grain turning hopper 1 and above to prevent grain from falling and causing congestion. It should be noted that the rotary tilting unit 30 is a lever-type rotary tilting structure, including a drive motor, a rotary spindle, and three sets of circumferentially distributed elastic tilting levers. The heat source for the drying fan 7 is supplied by an air-source heat pump hot air furnace, which is common in existing technologies.

[0024] The drying and diversion unit includes multiple baffles 11 fixedly installed on both sides inside the drying chamber 4. Heat exchange channels 13 are opened at equal intervals along the horizontal direction inside the multiple baffles 11. Heat exchange plates 12 are installed inside each heat exchange channel 13. A flow channel for grain to fall is provided between two adjacent sets of heat exchange plates 12. The fan chamber 8 is sealed on one side outside the upper and lower sets of baffles 11. Ladders 6 are fixedly installed on the outside of multiple drying chambers 4. In this embodiment, after the grain enters the drying chamber 4 from the feeding hopper 2, it flows slowly from top to bottom along the flow channel between two adjacent sets of heat exchange plates 12 under the action of gravity. Simultaneously, hot air enters the baffle 11 through the fan hopper 8 and then enters the heat exchange plates 12 through the heat exchange channel 13. The heat exchange plates 12, acting as an indirect heat exchange medium, transfer the heat carried by the hot air to the grain falling within the flow channel. Because the heat exchange plates 12 are evenly spaced horizontally and form uniform flow channels between adjacent heat exchange plates 12, the grain comes into full contact with the heat exchange plates 12 during its flow, achieving uniform and efficient indirect heating and drying.

[0025] The airflow guiding unit includes a storage box 32 connected to the inside of the diversion pipe 16. A hydraulic cylinder 21 is fixedly installed on one side inside the storage box 32. A connecting rod 24 is fixedly installed on the telescopic end of the hydraulic cylinder 21. A diversion arc plate 23 is fixedly installed on one end of the connecting rod 24. An arc-shaped ramp 22 is fixedly installed on the outer surface of one end of the diversion arc plate 23. One end of the diversion arc plate 23 extends movably into the inside of the air gathering pipe 14 to divert the airflow of the air gathering pipe 14 to the diversion pipe 16. In this embodiment, the hydraulic cylinder 21 drives the diversion arc plate 23 to move horizontally via the connecting rod 24, adjusting the depth of the diversion arc plate 23 extending into the air-gathering pipe 14. The arc-shaped ramp 22 at the end of the diversion arc plate 23 adopts a streamlined design, which can smoothly guide the concentrated airflow in the air-gathering pipe 14 to the diversion pipes 16 on both sides, avoiding the severe eddies and local resistance losses generated by traditional baffle diversion.

[0026] The side-flow air distribution unit includes a Venturi tube ejector 18 connected to one end of the air outlet pipe of the booster suction fan 20. The end of the Venturi tube ejector 18 away from the booster suction fan 20 is connected to a drain pipe 15 through a connecting unit. In this embodiment, the airflow output by the booster suction fan 20 enters the Venturi tube ejector 18. The Venturi tube ejector 18 has a converging nozzle and a diffuser section. As the airflow passes through the converging nozzle, its velocity increases sharply and its pressure drops sharply, creating a strong negative pressure zone at the nozzle outlet. This negative pressure zone draws in surrounding air into the main airflow through the bypass interface of the Venturi tube ejector 18, effectively doubling the airflow volume. The mixed airflow enters the diffuser section, where its velocity decreases and its pressure recovers, entering the diversion pipe 15 at a higher static pressure. Through the ejection effect of the Venturi tube ejector 18, the total amount of airflow entering the diversion pipe 15 is significantly increased without increasing the power consumption of the additional fan. Simultaneously, the diffuser section restores some pressure, ensuring sufficient driving force for the airflow in subsequent pipelines. This structure effectively solves the problem of insufficient airflow at the far end due to pressure loss in traditional diversion methods.

[0027] The connecting unit includes a vertical pipe 31 connected to the end of the Venturi tube ejector 18 and away from the booster suction fan 20. The end of the vertical pipe 31 away from the Venturi tube ejector 18 is connected to a bend pipe 25, which is internally connected to the drain pipe 15. In this embodiment, the mixed airflow from the Venturi ejector 18 passes sequentially through the vertical pipe 31 and the bend pipe 25 before entering the guide pipe 15. The vertical pipe 31 is arranged vertically, providing a stable section for the airflow before entering the bend pipe 25, which is beneficial for airflow homogenization. The bend pipe 25 adopts an elbow structure to ensure smooth airflow during the turning process and reduce local resistance loss.

[0028] Multiple heating units are inclinedly arranged on the inner wall of the drainage pipe 15. Drainage ventilation pipes 19 are installed at equal intervals along the horizontal direction inside the drainage pipe 15. Airflow extension units are arranged inside the drainage ventilation pipes 19. In this embodiment, as the hot air flows within the guide pipe 15, it first exchanges heat with multiple sets of heating units inclined to the inner wall, further homogenizing the airflow temperature. Subsequently, the hot air is evenly distributed by multiple guide ventilation pipes 19 installed at equal intervals along the horizontal direction, each guide ventilation pipe 19 corresponding to a drying area. Airflow extension units within the guide ventilation pipes 19 further guide the airflow downwards, allowing the hot air to penetrate deep into the distribution channel and fully contact the heat exchange fins 12. The inclined heating units on the inner wall of the guide pipe 15 increase the contact area between the airflow and the heating elements, improving heat exchange efficiency. The guide ventilation pipes 19 installed at equal intervals along the horizontal direction achieve secondary uniform distribution of airflow, ensuring that the airflow volume obtained by each drying area is essentially the same, eliminating the problem of uneven flow caused by differences in pipe layout. The airflow extension units effectively extend the airflow delivery distance, ensuring that sufficient hot air is also obtained at the far end of the distribution channel.

[0029] Multiple heating units include a mounting cylinder 27 fixedly installed on the inner wall of the drain pipe 15, a heat spreader 29 fixedly installed at one end of the mounting cylinder 27, and multiple guide plates 28 sequentially installed on the outer surface of the heat spreader 29 from top to bottom; In this embodiment, when hot air flows within the drainage pipe 15, it comes into full contact with the surfaces of the mounting cylinder 27, the heat spreader 29, and the multiple guide plates 28. The heat spreader 29 is made of a highly thermally conductive material, which can quickly absorb heat from the hot air and distribute it evenly across the entire plate surface. The guide plates 28 are arranged sequentially from top to bottom along the outer surface of the heat spreader 29, forming a multi-layered turbulence structure. This causes localized turbulence in the airflow as it passes through, disrupting the laminar boundary layer and thus significantly improving the convective heat transfer coefficient.

[0030] The airflow extension unit includes a rectangular tube 26 connected to one end of the airflow ventilation duct 19, and a V-shaped guide plate 17 is fixedly installed on the outside of the end of the rectangular tube 26 away from the airflow ventilation duct 19. In this embodiment, part of the hot air flowing out of the ventilation duct 19 blows directly onto the surface of the baffle 11, while part enters the rectangular tube 26 for diversion. The flat structure of the rectangular tube 26 causes the airflow to transition from a circular cross-section to a flat cross-section, which is beneficial for forming a uniform outlet velocity distribution. After the airflow exits from the rectangular tube 26, it impacts the V-shaped guide plate 17. The two wings of the V-shaped guide plate 17 open outward with smooth arc surfaces. The airflow generates a wall-attaching effect on the surface of the V-shaped guide plate 17, flowing along the plate surface to the sides and downwards, forming a wide wall-attached jet, which significantly increases the contact area and contact time between the hot air and the diversion channel wall.

[0031] Working Principle: During operation, the grain to be dried is fed into the feeding hopper 2 via the elevator 10 and connecting pipe 9. Under gravity, the grain enters multiple sequentially connected drying hoppers 4. Inside the drying hopper 4, the grain flows slowly from top to bottom along the flow channel between adjacent sets of heat exchange fins 12. Simultaneously, the drying fan 7 located on one side of the drying hopper 4 starts, sending hot air provided by an external heat source into the fan chamber 8. The hot air first enters the air-gathering pipe 14 within the fan chamber 8 for collection. Inside the air-gathering pipe 14, the airflow guiding unit begins to operate: according to the actual drying conditions, the hydraulic cylinder 21 in the storage box 32 drives the diversion arc plate 23 to extend into the air-gathering pipe 14 to a certain depth via the connecting rod 24. The arc-shaped ramp 22 at the end of the diversion arc plate 23 smoothly guides the concentrated airflow in the air-gathering pipe 14 to the diversion pipes 16 on both sides. By controlling the extension and retraction of the hydraulic cylinder 21, the insertion angle and depth of the diversion arc plate 23 can be dynamically adjusted, thereby precisely controlling the airflow ratio entering the two diversion pipes 16. The hot air entering the diversion pipe 16 is then actively pressurized by the booster suction fan 20 to overcome the friction loss along the pipe. The pressurized airflow enters the side flow equalization unit: the airflow first passes through the Venturi tube ejector 18, which utilizes the negative pressure effect generated by the high-speed airflow at the throat to draw in surrounding air into the main airflow, effectively doubling the airflow. The airflow from the Venturi tube ejector 18 enters the diversion pipe 15 through the vertical pipe 31 and the bend pipe 25. Inside the diversion pipe 15, the hot air flows along the pipe and exchanges heat with multiple heating units installed on the inner wall of the diversion pipe 15. Specifically, when hot air flows through the mounting cylinder 27 and the heat spreader 29, it comes into full contact with the heat spreader 29 and the multiple guide plates 28 installed sequentially from top to bottom on its outer surface, thereby efficiently transferring heat to the wall of the drain pipe 15 by increasing the heat exchange area. After homogenization and heating, the hot air is evenly distributed from multiple horizontally spaced ventilation pipes 19 inside the drainage pipe 15. Part of the airflow in each ventilation pipe 19 enters the rectangular pipe 26 at the end, while another part flows directly near the baffle 11. The airflow flowing into the rectangular pipe 26 is extended by the V-shaped guide plate 17. The V-shaped guide plate 17 guides the airflow into a wall-mounted jet that diffuses to the other end, resulting in a uniform airflow distribution in the upper and lower heat exchange areas on both sides of the fan chamber 8 within the drying chamber 4. The hot air enters the heat exchange plates 12 through horizontally spaced heat exchange channels 13 inside the baffle 11, where it indirectly exchanges heat with the grain falling in adjacent channels. As the grain passes through multiple drying chambers 4 from top to bottom, it sequentially exchanges heat with the heat exchange plates 12 at each level, gradually evaporating moisture. During the drying process, the rotating turning unit 30 located inside the grain turning silo 1 operates continuously to turn and disperse the grain during the falling process, preventing the grain from becoming congested or bridging due to excessive moisture, and ensuring the continuity and uniformity of material flow. After heat exchange, the airflow rises naturally inside the drying chamber 4 to dry the grain that enters next. The dried grain falls to the bottom of the turning silo 1 and is then conveyed by the screw conveyor 5 to the next process or re-enters the next drying cycle via the elevator 10, until the target moisture content is reached. Throughout this process, the airflow is dynamically distributed by the airflow guiding unit, the airflow is evenly distributed and energy is compensated by the side flow equalization unit, the airflow is directionally extended by the V-shaped guide plate 17, and the multi-stage drying chambers 4 are arranged in series to achieve tiered drying, thereby ensuring the uniformity, efficiency and stability of the drying process.

[0032] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A multi-stage circulating heat exchange drying tower structure for a grain dryer, comprising a grain turning bin (1), a feeding bin (2), a side loading platform (3), a screw feeder (5), a rotary turning unit (30), and an elevator (10), characterized in that, The spiral feeder (5) is installed inside the grain turning bin (1). Multiple drying bins (4) are sequentially connected and installed above the grain turning bin (1). The feeding bin (2) is installed above the drying bin (4) near the top. The elevator (10) is connected to the feeding bin (2) via a connecting pipe (9) at one end. A drying diversion unit is installed inside the drying bin (4). The side mounting platform (3) is fixedly installed on one side of the multiple drying bins (4), and a drying fan (7) is fixedly installed above the side mounting platform (3) and correspondingly near the drying bin (4). The drying fan (7) is connected to the drying bin. A fan compartment (8) is provided between the drying compartments (4). A gathering pipe (14) is connected to the air outlet of the fan compartment (8) and close to the drying fan (7). A diversion pipe (16) is connected to both sides of the gathering pipe (14). An airflow guiding unit is provided inside the diversion pipe (16). A booster suction fan (20) is connected to the end of the diversion pipe (16) away from the gathering pipe (14). A side flow equalization unit is provided at both the upper and lower ends of the air outlet pipe of the booster suction fan (20). The rotating turning unit (30) is located inside the grain turning compartment (1) and above it to prevent the grain from falling and causing congestion.

2. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 1, characterized in that, The drying and diversion unit includes multiple baffles (11) fixedly installed on both sides inside the drying chamber (4). Heat exchange channels (13) are opened at equal intervals along the horizontal direction inside the multiple baffles (11). Heat exchange plates (12) are installed inside each heat exchange channel (13). A flow channel for grain to fall is provided between two adjacent sets of heat exchange plates (12). The fan chamber (8) is sealed on one side outside the upper and lower sets of baffles (11). Ladders (6) are fixedly installed outside the multiple drying chambers (4).

3. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 1, characterized in that, The airflow guiding unit includes a storage box (32) connected to the inside of the diversion pipe (16) and installed above it. A hydraulic cylinder (21) is fixedly installed on one side inside the storage box (32). A connecting rod (24) is fixedly installed at the telescopic end of the hydraulic cylinder (21). A diversion arc plate (23) is fixedly installed at one end of the connecting rod (24). An arc-shaped ramp (22) is fixedly installed on the outer surface of one end of the diversion arc plate (23). One end of the diversion arc plate (23) extends movably into the inside of the air-gathering pipe (14) to divert the airflow of the air-gathering pipe (14) to the diversion pipe (16).

4. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 1, characterized in that, The side-flow air distribution unit includes a Venturi tube ejector (18) connected to one end of the air outlet pipe of the booster suction fan (20). The end of the Venturi tube ejector (18) away from the booster suction fan (20) is connected to a drain pipe (15) through a connecting unit.

5. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 4, characterized in that, The connecting unit includes a vertical pipe (31) connected to the end of the Venturi tube ejector (18) and away from the booster suction fan (20). The end of the vertical pipe (31) away from the Venturi tube ejector (18) is connected to a bend pipe (25), which is internally connected to the drain pipe (15).

6. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 4, characterized in that, The inner wall of the drainage pipe (15) is inclined and multiple heating units are provided. Drainage ventilation pipes (19) are installed at equal intervals along the horizontal direction inside the drainage pipe (15). Airflow extension units are provided inside the drainage ventilation pipes (19).

7. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 6, characterized in that, The multiple sets of heating units include a mounting cylinder (27) fixedly installed on the inner wall of the drain pipe (15), with a heat spreader (29) fixedly installed at one end of the mounting cylinder (27), and multiple guide plates (28) installed sequentially from top to bottom on the outer surface of the heat spreader (29).

8. The multi-stage circulating heat exchange drying tower structure for a grain dryer according to claim 6, characterized in that, The airflow extension unit includes a rectangular tube (26) connected to one end of the drainage ventilation pipe (19), and a V-shaped guide plate (17) is fixedly installed on the outside of the end of the rectangular tube (26) away from the drainage ventilation pipe (19).

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