A device for regulating the flow field inside a curing barn and a control method thereof

Abstract

This invention discloses a device for adjusting the flow field inside a drying oven, comprising: two lifting platforms, each distributed and installed on both sides of the drying oven, each platform including at least support rods and a first driving device for driving the support rods to move up and down; a lifting frame hinged between the two support rods, having several openings extending along the same axial direction, with first guide slots extending between adjacent openings; the two first driving devices independently drive the two support rods to move up and down, allowing the lifting frame to move as a whole above the air inlet of the drying oven, below the air inlet of the drying oven, or in an inclined state with a height difference between its two ends; a burlap sheet, a flexible woven plant fiber sheet, fixedly covering the openings; several flow guiding components, each correspondingly and movably inserted into the first guide slots; and a second driving device disposed on the lifting frame, comprising several transmission components and driving components.

Description

Technical Field

[0001] This invention belongs to the field of tobacco curing technology, and specifically relates to a device and control method for adjusting the flow field inside a curing barn. Background Technology

[0002] Tobacco curing is a crucial process that involves precisely controlling the temperature and humidity parameters within the curing barn to achieve moisture evaporation and the transformation of internal chemical components in tobacco leaves. Its final effect directly depends on the uniformity of the temperature and humidity field inside the curing barn. A uniform temperature and humidity field ensures that tobacco leaves from the same batch are heated and humidified consistently, guaranteeing the stability and uniformity of the leaves' color, aroma, and internal quality. Conversely, significant differences in temperature and humidity within the curing barn can lead to quality defects such as "greening," "ashing," "over-drying," or "over-wetting," severely impacting the grade and economic value of the tobacco leaves.

[0003] Existing conventional high-density drying ovens have inherent defects in structural design and airflow organization. After hot air enters from a single side vent, it lacks effective stratification and mixing within the oven, easily forming "hot spots" and "cold zones." To solve these problems, current technologies mostly improve the flow field distribution by installing fixed guide vanes or single flexible hemp sheets inside the drying oven.

[0004] However, the structure and angle of fixed baffles cannot be dynamically adjusted according to the temperature and humidity requirements at different stages of tobacco curing, making it difficult to fundamentally eliminate local temperature and humidity deviations. While a single flexible hemp sheet can achieve posture adjustment, it can only guide the airflow once as a whole, failing to achieve gradual dispersion and precise guidance of the airflow. During large-scale dehumidification, uneven airflow distribution still exists. Furthermore, existing baffle devices cannot independently control the baffle intensity at corresponding locations based on temperature and humidity deviations in different areas of the curing barn, thus failing to achieve comprehensive and precise control.

[0005] Currently, there is no curing barn internal adjustment device on the market that can simultaneously achieve overall posture adjustment and graded independent airflow, which cannot meet the stringent requirements of temperature and humidity uniformity for high-quality tobacco curing. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a device and a control method for adjusting the flow field inside a drying oven.

[0007] A device for regulating the flow field inside a drying oven, comprising: The elevator has two units, which are respectively installed on both sides of the drying room. It includes at least a support rod and a first drive device for driving the support rod to move up and down. The lifting frame is hinged between two support rods. Several openings are passed through it along the same axis. A first guide slot is passed through it between adjacent openings. The two support rods are independently driven by two first drive devices to lift and lower. The lifting frame can be moved as a whole to above the air inlet of the drying room, moved as a whole to below the air inlet of the drying room, or tilted with a height difference between the two ends. Hemp sheet, which is a flexible woven sheet of plant fiber, is fixedly covered in the opening; The flow guiding component has several parts, each corresponding to one another and movably inserted into the first guide slot, and can move to below the hemp sheet; The second drive device is mounted on the lifting frame and includes several transmission components and drive components. The transmission components are configured and connected to several guide components in a corresponding manner. The transmission components can drive the guide components to move up and down relative to the lifting frame, and the drive components can drive the transmission components to move sequentially.

[0008] In one embodiment, the flow guiding component includes an annular frame and a flow guiding plate. The annular frame is inserted vertically into a first guide slot. A second guide slot communicating with its inner ring is provided through the upper end of the annular frame. Movable slots are recessed on both sides of the inner ring of the annular frame. The flow guiding plate is inserted vertically into the second guide slot and can movably cover the inner ring area of ​​the annular frame. Guide blocks that can cooperate with the movable slots are provided on both sides of the flow guiding plate. A movable space is left between the guide blocks and the movable slots for the flow guiding plate to move vertically relative to the annular frame. A limiting block that can movably abut against the upper side of the lifting frame is provided at the upper end of the annular frame. In the initial state, the guide block abuts against the upper end of the movable groove, the guide plate is located above the annular frame and does not obstruct the inner ring area of ​​the annular frame, and the annular frame as a whole is located on the upper side of the lifting frame without extending downwards, and is in the storage state. When the guide plate is driven to move downward, the annular frame moves downward synchronously with its own gravity until the limiting block fixed at the upper end of the annular frame abuts against the lower side of the lifting frame, restricting the annular frame from moving further downward; at this time, the guide plate continues to be driven to move downward, and the guide block moves down along the movable groove until it abuts against the lower end of the movable groove. The guide plate is in a state of completely covering the inner ring of the annular frame, forming a guide baffle.

[0009] In one embodiment, the transmission component includes a movable seat, a guide shaft, a screw, a first gear, a first rack, a connecting rod, and a second gear. The guide shaft and the screw are coaxially mounted on the lifting frame, and both ends of the screw are rotatably mounted on the lifting frame via bearings. The movable seat is movably sleeved on the guide shaft via linear bearings, and the movable seat is threadedly connected to the screw. An oblique guide groove is provided through one side of the movable seat. A fixed shaft is provided on one side of the guide plate and above the annular frame. The fixed shaft is movably mounted in the oblique guide groove. The first gear is fixedly mounted on the screw along the same central axis. The first rack is movably mounted on one side of the lifting frame via a slide rail slider and is movably meshed with the first gear. The second gear is rotatably mounted on the lifting frame. The connecting rod is hinged between the second gear and the first rack. When the second gear is driven to rotate, it can drive the first rack to make reciprocating linear displacement through the connecting rod. The reciprocating displacement of the first rack drives the first gear to rotate in both directions, thereby driving the screw to rotate in both directions to drive the movable seat to move in both directions.

[0010] In one embodiment, the driving component includes a first sprocket and a second sprocket respectively rotatably mounted on the lifting frame, and a chain connected to the first sprocket and the second sprocket. The chain is provided with a second rack, which can be moved by the chain and sequentially mesh with a plurality of second gears. A drive motor is provided on one side of the lifting frame, and the drive shaft of the drive motor is connected to the first sprocket to drive the first sprocket to rotate.

[0011] In one embodiment, the first driving device includes a frame, a lifting motor, a transmission shaft, a lead screw, and a worm gear screw jack. The frame is fixedly installed inside the drying oven. The lifting motor is fixedly installed on the frame, and the output end of the lifting motor is connected to the transmission shaft. The transmission shaft is rotatably installed on the frame via bearings. The input end of the worm gear screw jack is connected to the transmission shaft, and the output end is connected to the lead screw. A support rod is threadedly connected to the lead screw to convert the rotational motion of the transmission shaft into the linear lifting motion of the lead screw. The support rod is movably mounted on the frame via a slide rail slider.

[0012] In one embodiment, the thickness of the jute sheet is 2mm to 5mm, specifically a jute fiber woven sheet.

[0013] In one embodiment, each of the lifting machines includes at least two worm gear screw jacks symmetrically distributed on both sides of the frame, with the drive shaft of the same lifting machine simultaneously connected to the input end of all corresponding worm gear screw jacks.

[0014] In one embodiment, the hemp sheet is fixed to the lifting seat by bolts or high-temperature resistant straps.

[0015] In one embodiment, the frame is welded from angle steel and coated with a high-temperature resistant and rust-proof coating.

[0016] A method for controlling the flow field inside a drying oven, comprising using the aforementioned device for controlling the flow field inside a drying oven, and further comprising the following steps: S1 In the early stage of tobacco leaf yellowing: control the two first drive devices to drive the support rod to rise synchronously, so that the lifting frame moves as a whole to above the air inlet of the curing barn. Control the second drive device to drive all the guide components to retract into the lifting frame, so that the circulating air enters the curing barn directly without obstruction, achieving rapid heating. S2 During the late yellowing stage of tobacco leaves to the middle stage of color fixing: the first drive device located on the air inlet side of the curing barn drives the support rod to rise to the highest position, and the first drive device located on the door side of the curing barn drives the support rod to fall to the lowest position, so that the lifting frame is in an inclined state with the front higher and the back lower; the second drive device is controlled to drive the guide component to extend from the air inlet side to the door side in sequence to the bottom of the hemp, and at this time the guide plate in the guide component is in the state of covering the inner ring area of ​​the ring frame, forming a multi-level guide surface, which gradually disperses the concentrated hot air to the entire area of ​​the curing barn; S3 During the middle of the tobacco leaf color fixing stage to the end of the drying stage: Control the two first drive devices to synchronously drive the support rod to descend, so that the entire lifting frame moves to below the air inlet of the curing barn. Control the second drive device to drive all the flow guiding components to retract into the lifting frame. At this time, the flow guiding plate in the flow guiding component is in the state of the inner ring area of ​​the uncovered annular frame. Hot air can be directly blown from the air inlet side of the curing barn to the door side through the inner ring area of ​​the annular frame and evenly dispersed through the burlap. At the same time, the burlap releases the moisture absorbed in the early stage to realize the re-moistening of the tobacco leaves.

[0017] In summary, the advantages of this invention compared to the prior art are: This invention uses a hinged lifting frame in conjunction with two independently driven flax lifting machines, which can achieve precise switching between three postures of the lifting frame: "above the air inlet, below the air inlet, and tilted state", to adapt to the airflow requirements of different baking stages; Furthermore, the lifting frame integrates hemp sheets and sequentially movable air guiding components, combining the moisture absorption and release functions of hemp sheets with the precise air guiding function of air guiding plates; the second driving device drives the air guiding components to move sequentially, which can realize the gradual dispersion and directional guidance of airflow, greatly improving the uniformity of temperature and humidity. Furthermore, the flow guiding component adopts a gravity-fed, double-layered nested structure, utilizing the weight of the annular frame itself to extend downwards. This eliminates the need for an additional drive mechanism to achieve linkage between the frame and the flow guiding plate, resulting in a simpler and more reliable structure. Through the step-by-step action of "frame extending first, then flow guiding plate covering," the effective flow guiding height of the flow guiding plate extending below the hemp sheet is ensured, while avoiding scratch damage between the flow guiding plate and the hemp sheet during the extension process. The limiting block is located at the upper end of the annular frame and abuts against the lower side of the lifting frame, providing high limiting accuracy and preventing the annular frame from falling off the first guide slot, significantly improving the operational safety of the device. Furthermore, it adopts a transmission structure of "screw, moving seat, and inclined guide groove" to convert the horizontal linear displacement of the moving seat into the vertical linear displacement of the guide plate, resulting in smooth transmission and high positioning accuracy. Through the crank-slider mechanism of "gear, rack, and connecting rod", the rotational motion of the second gear is converted into the reciprocating linear displacement of the first rack, thereby realizing the automatic up-and-down reciprocating extension and retraction of the guide plate. The structure is compact and occupies little space. Furthermore, it adopts a drive structure of "sprocket, chain, and segmented rack". Through the sequential meshing of a second rack with all the second gears, a single motor drives multiple flow guiding components to operate sequentially, which greatly reduces the number of drive motors and lowers the cost and control complexity of the device. The length of the second rack is equal to the center distance of the adjacent second gears, ensuring that only one flow guiding component operates at a time, avoiding mutual interference.

[0018] In addition, the present invention also provides a control method for adjusting the flow field inside the curing barn, which improves the uniformity of temperature and humidity inside the curing barn and is conducive to obtaining high-quality tobacco leaves through curing. Attached Figure Description

[0019] Figure 1 This is one of the cross-sectional views of a device for adjusting the flow field inside a drying oven according to an embodiment of the present invention; Figure 2 This is a second cross-sectional view of a device for adjusting the flow field inside a drying oven according to one embodiment of the present invention; Figure 3 This is a third cross-sectional view of a device for adjusting the flow field inside a drying oven, according to one embodiment of the present invention. Figure 4 This is an exploded view of a device for adjusting the flow field inside a drying oven according to one embodiment of the present invention; Figure 5 This is a perspective view of a device for adjusting the flow field inside a drying oven according to one embodiment of the present invention; Figure 6 This is a partial structural schematic diagram of a device for adjusting the flow field inside a drying oven, according to one embodiment of the present invention; Figure 7 This is a partial cross-sectional view of a device for adjusting the flow field inside a drying oven according to one embodiment of the present invention; Figure 8 This is a second partial structural schematic diagram of a device for adjusting the flow field inside a drying oven, according to one embodiment of the present invention. Figure 9 As one embodiment of the present invention Figure 8 Enlarged view of point A; Figure 10 This is a control logic framework diagram for adjusting the internal flow field of a drying oven in one embodiment of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: like Figures 1 to 10 The embodiment of the present invention preferably provides a device for adjusting the flow field inside a drying oven, comprising: two elevators 3 respectively installed on both sides of the drying oven 1, each elevator including at least support rods 5 and a first driving device 6 for driving the support rods 5 to move up and down; a lifting frame 21 hinged between the two support rods 5, having a plurality of openings 22 extending along the same axial direction therethrough, and a first guide slot 23 extending through between adjacent openings 22 therethrough, wherein the two first driving devices 6 independently drive the two support rods 5 to move up and down, allowing the lifting frame 21 to move as a whole above the air inlet of the drying oven 1, or as a whole to the air inlet of the drying oven 1. Below the air inlet, or at both ends forming a height difference and tilted; hemp sheet 2, which is a flexible plant fiber woven sheet, is fixedly covered in the opening 22; there are several flow guiding components 24, which are movably inserted into the first guide slot 23 and can move to below the hemp sheet 2; the second drive device is set on the lifting frame 21, which includes several transmission components 25 and drive components 26. The several transmission components 25 are configured and connected to the several flow guiding components 24 in a corresponding manner. The transmission components 25 can drive the flow guiding components 24 to move up and down relative to the lifting frame 21, and the drive components 26 can drive the several transmission components 25 to move sequentially.

[0021] Specifically, this device uses two first drive devices to drive the lifting frame to rise and fall at both ends, so that the lifting frame can form different overall postures and change the direction of the main airflow in the drying room. At the same time, it uses the moisture absorption and release properties of the flax itself to dynamically balance the humidity in the drying room. The second drive device drives multiple guide components to extend or retract in sequence, forming a multi-level guide surface under the flax, which disperses the concentrated hot air to different areas of the drying room step by step, realizing the fine control of airflow and ultimately improving the uniformity of temperature and humidity inside the drying room.

[0022] Furthermore, the flow guiding component 24 includes an annular frame 27 and a flow guiding plate 28. The annular frame 27 is inserted vertically into the first guide slot 23. The upper end of the annular frame 27 is provided with a second guide slot 29 that communicates with its inner ring. Movable slots 30 are recessed on both sides of the inner ring of the annular frame 27. The flow guiding plate 28 is inserted vertically into the second guide slot 29 and can movably cover the inner ring area of ​​the annular frame 27. The flow guiding plate 28 is provided with guide blocks 31 on both sides that can cooperate with the movable slots 30. There is a space between the guide blocks 31 and the movable slots 30 for the flow guiding plate 28 to move vertically relative to the annular frame 27. The upper end of the annular frame 27 is provided with a limiting block 32 that can movably abut against the upper side of the lifting frame 21. In the initial state, the guide block 31 abuts against the upper end of the movable groove 30, the guide plate 28 is located above the annular frame 27 and does not obstruct the inner ring area of ​​the annular frame 27, and the annular frame 27 is located on the upper side of the lifting frame 21 without extending downward, and is in a retracted state. When the guide plate 28 is driven to move downward, the annular frame 27 moves downward synchronously with its own gravity until the limiting block 32 fixed at the upper end of the annular frame 27 abuts against the lower side of the lifting frame 21, restricting the annular frame 27 from continuing to move downward; at this time, the guide plate 28 continues to be driven to move downward, and the guide block 31 moves down along the movable groove 30 until it abuts against the lower end of the movable groove 30. The guide plate 28 is in a state of completely covering the inner ring of the annular frame 27, forming a guide baffle.

[0023] Specifically, when in the initial storage state (applicable to the drying stage / early yellowing stage), when the transmission component has no driving force output, the guide block naturally abuts against the upper end of the movable groove, and the guide plate is suspended above the annular frame, completely opening the inner ring channel of the annular frame without any airflow obstruction; at this time, the annular frame is stored in the upper plane of the lifting frame and does not extend downwards. The entire guide component does not occupy the effective airflow space inside the drying chamber, and hot air can pass directly through the inner ring area of ​​the annular frame smoothly.

[0024] When the flow guiding operation is switched (applicable to the color fixing stage), the transmission component outputs a downward driving force to drive the flow guide plate downward: First stage (synchronous descent): Due to the rigid contact between the guide block and the upper end of the movable groove, the initial stage of the flow guide plate's downward displacement will cause the annular frame to overcome the friction with the first guide groove opening and extend downward synchronously with its own weight; Second stage (frame limiting): When the annular frame extends downward until the limiting block at its upper end abuts against the lower surface of the lifting frame, the annular frame is mechanically limited and cannot continue to move downward. At this time, the lower part of the annular frame has extended below the hemp sheet; Third stage (flow guide plate coverage): The flow guide plate continues to move downward under the driving force, and the guide block slides downward along the inner wall of the movable groove until the guide block abuts against the lower end of the movable groove. The flow guide plate completely covers the inner ring area of ​​the annular frame, forming a continuous and complete flow guide baffle, realizing the blocking and directional guidance of airflow.

[0025] When the guide plate needs to be retracted, the transmission component outputs an upward driving force to move the guide plate upward: first, the guide block slides upward along the movable groove until it abuts the upper end of the movable groove, and the guide plate returns to the unobstructed state above the annular frame; then the guide plate continues to move upward, and through the guide block, it drives the annular frame to retract upward synchronously until the annular frame completely returns to the initial storage position on the upper side of the lifting frame.

[0026] Further, the transmission component 25 includes a movable seat 41, a guide shaft 42, a screw 43, a first gear 44, a first rack 45, a connecting rod 46, and a second gear 47. The guide shaft 42 and the screw 43 are coaxially arranged on the lifting frame 21, and both ends of the screw 43 are rotatably mounted on the lifting frame 21 via bearings. The movable seat 41 is movably sleeved on the guide shaft 42 via linear bearings, and the movable seat 41 is threadedly connected to the screw 43. An oblique guide groove 48 is provided through one side of the movable seat 41. A fixed shaft 49 is provided on one side of the guide plate 28 and above the annular frame 27. The fixed shaft 49 is movably mounted on... The first gear 44 is fixedly mounted on the screw 43 with the same central axis and placed in the inclined guide groove 48. The first rack 45 is movably mounted on one side of the lifting frame 21 via a slide rail slider and is movably meshed with the first gear 44. The second gear 47 is rotatably mounted on the lifting frame 21. The connecting rod 46 is hinged between the second gear 47 and the first rack 45. When the second gear 47 is driven to rotate, it can drive the first rack 45 to make reciprocating linear displacement through the connecting rod 46. The reciprocating displacement of the first rack 45 drives the first gear 44 to rotate forward and backward, thereby driving the screw 43 to rotate forward and backward to drive the moving seat 41 to move forward and backward.

[0027] Specifically, when the second gear is driven to rotate, the first rack is driven to reciprocate linearly along the slide rail through the eccentrically hinged connecting rod; the first rack meshes with the first gear, driving the first gear and the screw to rotate synchronously in both directions; the screw is threadedly connected to the moving seat, and the moving seat is restricted from rotation by the guide shaft, so the rotation of the screw will be converted into the horizontal reciprocating movement of the moving seat along the guide shaft; the inclined guide groove on the moving seat cooperates with the fixed shaft at the upper end of the guide plate, converting the horizontal displacement of the moving seat into the vertical up-and-down displacement of the guide plate, realizing the extension and retraction of the guide plate, and the drive of the inclined guide groove can realize the rapid displacement conversion of short stroke driving long stroke.

[0028] Furthermore, the driving component includes a first sprocket 50 and a second sprocket 56 respectively rotatably mounted on the lifting frame 21, and a chain 52 drivingly connected between the first sprocket 50 and the second sprocket 56. The chain 52 is provided with a second rack 53, which can be displaced by the chain 52 and sequentially mesh with a plurality of second gears 47. A drive motor 55 is provided on one side of the lifting frame 21, and the drive shaft of the drive motor 55 is connected to the first sprocket 50 to drive the first sprocket 50 to rotate.

[0029] Specifically, after the drive motor starts, it drives the first sprocket to rotate, which in turn drives the second sprocket to rotate synchronously via the transmission chain. The second rack, fixed on the transmission chain, moves synchronously with the chain. When the second rack moves to mesh with the first second gear, it drives the second gear to rotate one revolution, which in turn drives the corresponding first guide component to complete one extension or retraction action via the transmission component. As the chain continues to move, the second rack meshes with the subsequent second gears in sequence, realizing the sequential action of all guide components. Since the length of the second rack is equal to the center distance of the adjacent second gears, only one second gear meshes with the second rack at a time, ensuring that the guide components act independently and sequentially without interfering with each other.

[0030] Furthermore, the first driving device 6 includes a frame 7, a lifting motor 8, a transmission shaft 9, a lead screw 10, and a worm gear type screw jack 51. The frame 7 is fixedly installed inside the drying oven 1. The lifting motor 8 is fixedly installed on the frame 7, and the output end of the lifting motor 8 is connected to the transmission shaft 9. The transmission shaft 9 is rotatably installed on the frame 7 through bearings. The input end of the worm gear type screw jack 51 is connected to the transmission shaft 9, and the output end is connected to the lead screw 10. The support rod 5 is threadedly connected to the lead screw 10 and is used to convert the rotational motion of the transmission shaft 9 into the linear lifting motion of the lead screw 10. The support rod 5 is movably mounted on the frame 7 via a slide rail slider.

[0031] Specifically, after the lifting motor starts, it outputs rotational power, which drives the transmission shaft to rotate synchronously through the coupling. The transmission shaft synchronously transmits the rotational power to the input worm of all worm gear screw jacks. The worm meshes with the worm wheel, converting the horizontal rotational motion into vertical rotational motion. The worm wheel drives the screw, which is fixedly connected to it, to rotate uniformly around its own axis. Since the support rod is threadedly connected to the screw, and both ends of the support rod are slidably connected to the frame through a slide rail slider mechanism, the rigidity of the slide rail slider mechanism restricts the rotational freedom of the support rod. Therefore, the rotating screw, through the threaded engagement, converts its own rotational motion into a pure axial vertical linear displacement of the support rod, thereby driving the lifting frame to adjust its height and tilt angle.

[0032] Furthermore, the thickness of the jute sheet 2 is 2mm to 5mm, specifically a jute fiber woven sheet.

[0033] Specifically, in a humid environment, it can slowly release absorbed moisture, increasing the humidity inside the drying room and achieving a dynamic balance of humidity. At the same time, the burlap has a certain air permeability resistance. When hot air passes through the burlap, it is dispersed into multiple small airflows by the fiber gaps of the burlap, promoting the mixing of hot and cold air and improving temperature uniformity.

[0034] Furthermore, each of the lifting machines 3 includes at least two worm gear screw jacks 51, symmetrically distributed on both sides of the frame 7, and the drive shaft 9 of the same lifting machine 3 is simultaneously connected to the input end of all the corresponding worm gear screw jacks 51.

[0035] Specifically, at least two worm gear screw jacks are symmetrically arranged on both sides of the frame of the same hemp fiber lifting machine. All screw jacks are connected to the input end of the same drive shaft at the same time. Driven by the lifting motor, the drive shaft drives the worm of each screw jack to rotate synchronously at the same speed and in the same direction. This makes the transmission stroke and lifting speed of the worm gear and screw inside each screw jack completely consistent, so as to achieve equal speed, same stroke and smooth lifting at both ends of the support rod, and avoid the support rod being subjected to force on one side, tilting, jamming or twisting deformation.

[0036] Furthermore, the hemp sheet 2 is fixed to the lifting seat 54 by bolts or high-temperature resistant straps.

[0037] Specifically, the burlap slabs are flexibly and tightly fixed to the edge of the rectangular opening of the lifting frame using bolts or high-temperature resistant straps. This ensures reliable fixation without damaging the structure of the burlap slabs themselves, while also allowing for a certain amount of deformation allowance. When a height difference is formed between the two ends of the lifting frame, causing the lifting frame to tilt, the burlap slabs can naturally bend with the tilt of the lifting frame to form a smooth slope, without causing stress concentration, tearing, or wrinkling due to rigid fixation.

[0038] Furthermore, the frame 7 is made of angle steel welded together and its surface is coated with a high-temperature resistant and rust-proof coating.

[0039] Specifically, the frame welded from angle steel has high bending and torsional strength, which can stably support the weight of the lifting frame, hemp sheets and all transmission components; the high-temperature resistant and rust-proof coating sprayed on the surface can effectively isolate air and moisture in the high temperature and high humidity environment of the drying room (up to 70°C), prevent the angle steel from rusting and corroding, and extend the service life of the frame.

[0040] A method for controlling the flow field inside a drying oven, comprising using the aforementioned device for controlling the flow field inside a drying oven, and further comprising the following steps: S1 In the early stage of tobacco leaf yellowing: control the two first drive devices 6 to drive the support rod 5 to rise synchronously, so that the lifting frame 21 moves as a whole to the air inlet of the curing barn, and control the second drive device to drive all the guide components 24 to retract into the lifting frame 21, so that the circulating air enters the curing barn directly without obstruction, achieving rapid heating. S2 During the late yellowing stage of tobacco leaves to the middle stage of color fixing: the first drive device 6 located on the air inlet side of the curing barn 1 drives the support rod 5 to rise to the highest position, and the first drive device 6 located on the door side of the curing barn 1 drives the support rod 5 to fall to the lowest position, so that the lifting frame 21 is in an inclined state with the front higher and the back lower; the second drive device is controlled to drive the guide component 24 to extend from the air inlet side to the door side in sequence to below the flax 2, and at this time the guide plate 28 in the guide component 24 is in the state of covering the inner ring area of ​​the shielding ring frame 27, forming a multi-level guide surface, which gradually disperses the concentrated hot air to the entire curing barn area; S3 During the middle of the tobacco leaf color fixing stage to the end of the drying stage: Control the two first drive devices 6 to drive the support rod 5 to descend synchronously, so that the lifting frame 21 moves as a whole to below the air inlet of the curing barn. Control the second drive device to drive all the guide components 24 to retract into the lifting frame 21. At this time, the guide plate 28 in the guide component 24 is in the state of the inner ring area of ​​the uncovered annular frame 27. Hot air can be directly blown from the air inlet side of the curing barn to the door side through the inner ring area of ​​the annular frame 27 and evenly dispersed through the flax 2. At the same time, the flax 2 releases the moisture absorbed in the early stage to realize the re-moistening of the tobacco leaves.

[0041] Specifically, the working principle of the control method includes: Early stage of yellowing: The curing room is at low temperature and high humidity (30-38℃), with relatively uniform temperature and humidity distribution, requiring rapid heating. At this time, the lifting frame is moved above the air inlet, the air guiding components are fully retracted, and the circulating air enters the curing room directly without obstruction. The hot air is concentrated and blown towards the middle and rear of the curing room, and then diffuses naturally to other areas, achieving rapid heating.

[0042] From the late yellowing stage to the mid-color-fixing stage: the temperature and humidity inside the curing barn are moderate (38-50℃), the tobacco leaves evaporate a lot of moisture, requiring large-scale dehumidification, and the temperature and humidity uniformity is the worst. At this time, the lifting frame is tilted with the front higher than the back, and the air guiding components extend sequentially from the air inlet side to the door side. The air guiding plate completely covers the inner ring of the annular frame, forming a multi-level air guiding surface, which disperses the concentrated hot air to the sides and lower layers of the curing barn step by step, avoiding the formation of "hot spots" in the upper part of the curing barn; at the same time, the burlap absorbs excess moisture in the air, reducing the humidity of the airflow.

[0043] From the middle of the color-fixing stage to the end of the drying stage: The curing barn is hot and humid (50-70℃). The heat decay leads to a large temperature difference between the front and back ends, and the tobacco leaves need to re-moisten. At this time, the lifting frame moves below the air inlet, all the guide components retract, and the guide plate moves upward to the upper end of the movable slot, so that the inner ring of the annular frame is completely open. Hot air can pass directly through the inner ring of the annular frame, and then through the flax leaves and be evenly dispersed, improving temperature uniformity; at the same time, the moisture absorbed by the flax leaves in the previous stage is slowly released, achieving natural re-moistening.

[0044] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. 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 illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for regulating the flow field inside a curing barn, characterized in that, include: The elevator (3) has two elevators, which are respectively installed on both sides of the baking room (1). Each elevator includes at least a support rod (5) and a first drive device (6) for driving the support rod (5) to move up and down. The lifting frame (21) is hinged between two support rods (5). Several openings (22) are passed through it along the same axis. A first guide slot (23) is passed through it between adjacent openings (22). The two support rods (5) are independently driven by two first drive devices (6) to lift and lower. The lifting frame (21) can be moved as a whole to above the air inlet of the drying room (1), or moved as a whole to below the air inlet of the drying room (1), or the two ends form a height difference and are in an inclined state. Fiber sheet (2), which is a flexible plant fiber woven sheet, is fixedly covered in the opening (22); The flow guiding component (24) has several of them, and each of them is movably inserted into the first guide slot (23) and can move to the bottom of the hemp sheet (2); The second drive device is mounted on the lifting frame (21) and includes several transmission components (25) and drive components (26). The several transmission components (25) are connected to several guide components (24) in a one-to-one correspondence. The transmission components (25) can drive the guide components (24) to move up and down relative to the lifting frame (21). The drive components (26) can drive the several transmission components (25) to move in sequence.

2. A device for regulating the flow field inside a curing barn according to claim 1, characterized in that: The flow guiding component (24) includes an annular frame (27) and a flow guiding plate (28). The annular frame (27) is inserted into the first guide slot (23) at the top and bottom. The upper end of the annular frame (27) is provided with a second guide slot (29) that communicates with its inner ring. Movable slots (30) are recessed on both sides of the inner ring of the annular frame (27). The flow guiding plate (28) is inserted into the second guide slot (29) at the top and bottom and can movably cover the inner ring area of ​​the annular frame (27). The flow guiding plate (28) is provided with guide blocks (31) on both sides that can cooperate with the movable slots (30). There is a space between the guide blocks (31) and the movable slots (30) for the flow guiding plate (28) to move up and down relative to the annular frame (27). The upper end of the annular frame (27) is provided with a limiting block (32) that can movably abut against the upper side of the lifting frame (21). In the initial state, the guide block (31) abuts against the upper end of the movable groove (30), the guide plate (28) is located above the annular frame (27) and does not obstruct the inner ring area of ​​the annular frame (27), the annular frame (27) is located on the upper side of the lifting frame (21) without extending downward, and is in the storage state; When the guide plate (28) is driven to move downward, the annular frame (27) moves downward synchronously with its own gravity until the limiting block (32) fixed at the upper end of the annular frame (27) abuts against the lower side of the lifting frame (21), restricting the annular frame (27) from continuing to move downward; at this time, the guide plate (28) continues to be driven to move downward, and the guide block (31) moves down along the movable groove (30) until it abuts against the lower end of the movable groove (30). The guide plate (28) is in a state of completely covering the inner ring of the annular frame (27), forming a guide baffle.

3. The device for adjusting the flow field inside a drying oven according to claim 2, characterized in that: The transmission component (25) includes a movable seat (41), a guide shaft (42), a screw (43), a first gear (44), a first rack (45), a connecting rod (46), and a second gear (47). The guide shaft (42) and the screw (43) are coaxially arranged on the lifting frame (21), and the two ends of the screw (43) are rotatably mounted on the lifting frame (21) through bearings. The movable seat (41) is movably sleeved on the guide shaft (42) through a linear bearing, and the movable seat (41) is threadedly connected to the screw (43). An inclined guide groove (48) is provided through one side of the movable seat (41). A fixed shaft (49) is provided on one side of the guide plate (28) and above the annular frame (27). The movable part is set in the inclined guide groove (48). The first gear (44) is fixedly set on the screw (43) with the same central axis. The first rack (45) is movably set on one side of the lifting frame (21) through the slide rail slider and is movably meshed with the first gear (44). The second gear (47) is rotatably set on the lifting frame (21). The connecting rod (46) is hinged between the second gear (47) and the first rack (45). When the second gear (47) is driven to rotate, it can drive the first rack (45) to make reciprocating linear displacement through the connecting rod (46). The first rack (45) moves back and forth to drive the first gear (44) to rotate forward and backward, and then drive the screw (43) to rotate forward and backward to drive the moving seat (41) to move back and forth.

4. The device for adjusting the flow field inside a drying oven according to claim 3, characterized in that: The driving component includes a first sprocket (50) and a second sprocket (56) respectively rotatably mounted on the lifting frame (21), and a chain (52) drivingly connected between the first sprocket (50) and the second sprocket (56). The chain (52) is provided with a second rack (53), which can be moved by the chain (52) and sequentially mesh with a plurality of second gears (47). A drive motor (55) is provided on one side of the lifting frame (21), and the drive shaft of the drive motor (55) is connected to the first sprocket (50) to drive the first sprocket (50) to rotate.

5. The device for adjusting the flow field inside a drying oven according to claim 1, characterized in that: The first driving device (6) includes a frame (7), a lifting motor (8), a transmission shaft (9), a lead screw (10), and a worm gear type screw jack (51). The frame (7) is fixedly installed in the baking room (1). The lifting motor (8) is fixedly installed on the frame (7). The output end of the lifting motor (8) is connected to the transmission shaft (9). The transmission shaft (9) is rotatably installed on the frame (7) through bearings. The input end of the worm gear type screw jack (51) is connected to the transmission shaft (9), and the output end is connected to the lead screw (10). The support rod (5) is threadedly connected to the lead screw (10) to convert the rotational motion of the transmission shaft (9) into the linear lifting motion of the lead screw (10). The support rod (5) is movably installed on the frame (7) through a slide rail slider.

6. The device for adjusting the flow field inside a drying oven according to claim 1, characterized in that: The thickness of the burlap sheet (2) is 2mm to 5mm, specifically a woven sheet of jute fiber.

7. The device for adjusting the flow field inside a drying oven according to claim 5, characterized in that: Each of the lifting machines (3) includes at least two worm gear screw jacks (51), symmetrically distributed on both sides of the frame (7), and the drive shaft (9) of the same lifting machine (3) is simultaneously connected to the input end of all the corresponding worm gear screw jacks (51).

8. The device for adjusting the flow field inside a drying oven according to claim 1, characterized in that: The hemp sheet (2) is fixed to the lifting seat (54) by bolts or high-temperature resistant straps.

9. The device for adjusting the flow field inside a drying oven according to claim 5, characterized in that: The frame (7) is made of angle steel welded together and the surface is coated with a high-temperature resistant and rust-proof coating.

10. A control method for adjusting the flow field inside a drying oven, characterized in that: The device for adjusting the flow field inside the drying oven, as described in any one of claims 1-9, further includes the following steps: S1 In the early stage of the yellowing of tobacco leaves: control the two first drive devices (6) to drive the support rod (5) to rise synchronously, so that the lifting frame (21) moves as a whole to the air inlet of the curing barn, and control the second drive device to drive all the guide components (24) to retract into the lifting frame (21), so that the circulating air enters the curing barn directly without obstruction, and achieves rapid heating; S2 During the late yellowing stage of tobacco leaves to the middle stage of color fixing: control the first drive device (6) located on the air inlet side of the curing barn (1) to drive the support rod (5) to rise to the highest position, and control the first drive device (6) located on the door side of the curing barn (1) to drive the support rod (5) to fall to the lowest position, so that the lifting frame (21) is in an inclined state with the front higher and the back lower; control the second drive device to drive the guide component (24) to extend from the air inlet side to the door side to the bottom of the flax (2), and at this time the guide plate (28) in the guide component (24) is in the state of covering the inner ring area of ​​the shielding ring frame (27), forming a multi-level guide surface, and dispersing the concentrated hot air to the whole area of ​​the curing barn step by step; S3 From the middle of the tobacco leaf color fixing stage to the end of the dry barn stage: Control the two first drive devices (6) to drive the support rod (5) to descend synchronously, so that the lifting frame (21) moves as a whole to below the air inlet of the curing barn. Control the second drive device to drive all the guide components (24) to retract into the lifting frame (21). At this time, the guide plate (28) in the guide component (24) is in the state of the inner ring area of ​​the uncovered ring frame (27). Hot air can be blown directly from the air inlet side of the curing barn to the door side through the inner ring area of ​​the ring frame (27) and be evenly dispersed through the hemp sheet (2). At the same time, the hemp sheet (2) releases the moisture absorbed in the early stage to realize the re-moistening of the tobacco leaves.

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