A double-layer air circulation tobacco leaf dusting inhibitor fumigation device

Abstract

The utility model provides a kind of double-layer airflow circulation tobacco hanging dust inhibitor fumigation device, belong to fumigation device technical field, this double-layer airflow circulation tobacco hanging dust inhibitor fumigation device includes: fumigation cabin, top is equipped with horizontal suspension shaft;Eccentric gravity ring, by ball bearing with the way of free rotation around its own axis is hung in the suspension shaft, the gravity center of the eccentric gravity ring is deviated relative to its geometric axis;Several magnetic hanging leaf clamps are evenly distributed on the ring body, and the clamping surface of the hanging leaf clamp faces the radial inner side of the ring body, for fixing tobacco leaf in overhanging manner;Fumigation cabin bottom is equipped with ascending hot air flow channel, and the outlet of the hot air flow channel is located below the eccentric gravity ring;When eccentric gravity ring rotates, tobacco leaf reciprocating swing under the coupling effect of gravity and inertia, form dynamic fumigation state;Solve the problem that tobacco film is not uniform, ash secondary attachment and vein breakage caused by static fumigation.

Description

Technical Field

[0001] This utility model belongs to the technical field of fumigation devices, specifically, it relates to a fumigation device for a double-layer airflow circulating tobacco ash inhibitor. Background Technology

[0002] After processing, tobacco leaves require fumigation with ash inhibitors to form a uniform fumigant film on the leaf surface, inhibiting mold growth and reducing ash adhesion during storage. Existing fumigation devices mostly employ fixed hanging rods or horizontal chain structures: the tobacco leaves are clamped and suspended statically in a sealed chamber, with a heat source at the bottom vaporizing the fumigant, and the hot airflow penetrating the leaf layer from bottom to top to complete the fumigation. While this approach is simple in structure and has a large loading capacity, it has revealed three common problems in long-term production practice. Firstly, static suspension keeps the blades in the same position, resulting in saturation of fumigant on the underside of the blades facing the airflow, while the underside of the blades, where they meet adjacent blades, receives insufficient fumigant, creating "yin-yang surfaces" and "adhesive white cores," which easily lead to localized mold growth during later storage. Secondly, the leaf veins become soft in a prolonged high-temperature, high-humidity environment without mechanical disturbance, making them prone to breakage and tearing during manual pulling during unloading, reducing the integrity rate and increasing losses during downstream re-drying. Thirdly, ash and tar particles migrate upwards with the airflow and redeposit on the cooler underside of the blades, forming "secondary ash accumulation," which weakens the inhibitory effect. To alleviate these defects, some equipment adds circulating fans or intermittent oscillating mechanisms. However, fan blades are easily corroded and scaled by fumigant, leading to dynamic imbalance and increased noise. Oscillating mechanisms require components such as motors, gearboxes, and sealing slip rings, increasing energy consumption and structural complexity, adding an extra burden to cleanroom maintenance. Therefore, the industry urgently needs a new fumigation method that can achieve continuous changes in tobacco leaf posture, synchronous deashing, and maintain leaf vein rigidity without external power and relying on its own structure. Utility Model Content

[0003] In view of this, the present invention provides a double-layer airflow circulating tobacco leaf ash inhibitor fumigation device, which solves the problems of uneven film formation, secondary ash adhesion, and leaf vein damage caused by static fumigation.

[0004] This utility model is implemented as follows:

[0005] This utility model provides a double-layer airflow circulating tobacco leaf ash inhibitor fumigation device, which includes:

[0006] The fumigation chamber is equipped with a horizontal suspension shaft at the top;

[0007] An eccentric gravity ring is suspended from the suspension shaft by ball bearings in a manner that allows it to rotate freely around its own axis. The center of gravity of the eccentric gravity ring is offset from its geometric axis, giving the ring a unidirectional rotational tendency under the action of gravitational torque.

[0008] Several magnetic leaf clips are evenly distributed around the ring body, with the clamping surface of the leaf clips facing the radial inner side of the ring body, for fixing tobacco leaves in a suspended manner.

[0009] The bottom of the fumigation chamber is provided with an upward hot airflow channel. The outlet of the hot airflow channel is located below the eccentric gravity ring, so that the upward airflow directly impacts the lower edge of the ring and drives the ring to rotate slowly and continuously.

[0010] When the eccentric gravity ring rotates, the tobacco leaves oscillate back and forth under the coupling of gravity and inertia, forming a dynamic fumigation state.

[0011] The technical effects of the dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device provided by this utility model are as follows: By suspending the eccentric gravity ring at the top of the fumigation chamber with ball bearings and deviating its center of gravity from the geometric axis, the device can drive the ring to rotate continuously and slowly with only the help of rising hot airflow. During the rotation, the tobacco leaves swing naturally due to the coupling of gravity and inertia, forming a dynamic fumigation state. Thus, without adding any external power or control components, the inertial shedding of ash between leaves is achieved, avoiding the adhesion of leaf veins caused by static hanging, and significantly improving the integrity and cleanliness of the leaves after fumigation.

[0012] Based on the above technical solution, the dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device of this utility model can be further improved as follows:

[0013] The eccentric gravity ring is a closed ring formed by integral casting. The wall thickness of the ring changes continuously along the circumference. The area with the largest wall thickness constitutes the center of gravity offset part, and the area with the smallest wall thickness is located on the opposite side of the center of gravity offset part, so that the center of gravity deviates from the geometric axis.

[0014] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the ring body adopts a closed ring with continuously varying wall thickness, and a stable center of gravity offset can be formed by utilizing the difference in its own wall thickness. No additional counterweight is required, which simplifies the structure while ensuring continuous and reliable rotational driving force and reducing manufacturing and maintenance costs.

[0015] Furthermore, the outer ring of the ball bearing is interference-fitted with the suspension shaft at the top of the fumigation chamber, and the inner ring is interference-fitted with the protrusion on the upper end face of the eccentric gravity ring, so that the ring can rotate freely around the axis without external driving force after suspension.

[0016] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the outer ring of the ball bearing and the suspension shaft, and the inner ring and the protrusion of the ring body are all interference fit, forming a pure mechanical suspension scheme without bolts or welding. After assembly, the ring body can rotate freely without external driving force, which ensures coaxiality, avoids running noise, and extends service life.

[0017] Furthermore, the magnetic leaf clamp includes a fixed jaw, a movable jaw, and a permanent magnet. The fixed jaw extends integrally with the ring body, the movable jaw is pivotally connected to the fixed jaw, and the permanent magnet is embedded between the mating surfaces of the fixed jaw and the movable jaw, forming a boltless quick clamping structure.

[0018] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the magnetic leaf clamp closes the fixed jaw and the movable jaw with a permanent magnet, realizing the rapid clamping and release of tobacco leaves, eliminating the need for threaded or spring components, reducing the number of parts, avoiding the failure problem caused by fumigant corrosion of metal springs, and at the same time, the magnetic force is evenly distributed, reducing the risk of leaf petiole crushing.

[0019] Furthermore, the outlet of the rising hot airflow channel of the fumigation chamber is slit-shaped, with the length direction of the slit parallel to the tangential direction of the annulus, so that the hot airflow impacts the lower circumferential area of ​​the annulus in a curtain-like manner.

[0020] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the slit-shaped outlet allows the hot airflow to uniformly impact the circumferential area of ​​the lower edge of the annulus in a curtain-like manner, avoiding local overheating or rotational stagnation caused by point-like airflow, ensuring that the annulus obtains a stable and continuous tangential thrust, maintaining low-speed uniform rotation, and improving fumigation uniformity. The slit-shaped outlet refers to a continuous, equal-width slit whose length direction is parallel to the tangent of the eccentric gravity ring. Its width is uniform and much smaller than its length. The two ends of the slit are closed, allowing the hot airflow to flow out uniformly in the form of a thin curtain, forming a linear thrust zone.

[0021] Furthermore, the top wall of the fumigation chamber is provided with a downwardly protruding annular retaining ring, which is located on the outer periphery of the eccentric gravity ring and maintains a radial gap with the ring body to limit the radial swing amplitude when the ring body rotates.

[0022] The beneficial effects of the above-mentioned improved scheme are as follows: the annular baffle ring on the top wall forms a radial limit on the outer periphery of the ring body, which allows the ring body to rotate freely while preventing excessive radial swaying caused by uneven tobacco leaf distribution or sudden airflow changes, thus ensuring stable operation and a safe clearance in the cabin space. This clearance is greater than the expected radial displacement of the ring body caused by uneven tobacco leaf distribution or airflow impact in any radial direction, and less than the critical distance for rigid collision between the ring body and the baffle ring.

[0023] Furthermore, the lower edge of the eccentric gravity ring is provided with circumferentially distributed arc-shaped fins, the concave surface of which faces the direction of the hot airflow, in order to increase the tangential thrust of the airflow on the ring.

[0024] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the concave surface of the arc-shaped fins at the lower edge of the ring body faces the direction of the hot airflow, increasing the effective force-bearing area, converting more airflow kinetic energy into tangential thrust, and enabling reliable start-up and maintenance of rotation even at low airflow speeds, reducing dependence on heat source power.

[0025] Furthermore, the clamping surface of the magnetic leaf clamp is provided with transversely continuous wavy teeth, which are used to increase the clamping friction and reduce local stress concentration in the leaf veins when the tobacco leaves swing.

[0026] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the wavy teeth on the clamping surface provide multi-point flexible support when the tobacco leaf swings, disperse the stress of the leaf veins, prevent slippage, reduce local indentations, and maintain the integrity of the tobacco leaf appearance.

[0027] Furthermore, the bottom of the fumigation chamber is also provided with a return air loop. The air inlet of the return air loop is located at the lower part of the chamber wall, and the air outlet is located at the entrance side of the hot airflow channel, forming a circulating airflow path from bottom to top, so that the eccentric gravity ring is always surrounded by the rising airflow.

[0028] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the return air loop will guide the sinking airflow back into the hot airflow channel, forming a bottom-up circulation path in the cabin, so that the eccentric gravity ring is always surrounded by a stable rising airflow, prolonging the contact time between the fumigant and the tobacco leaves, improving the utilization rate and reducing dead zones.

[0029] Furthermore, the axial width of the eccentric gravity ring gradually narrows from top to bottom, forming an inverted conical ring, which is used to reduce the weight of the ring and increase the radial openness of the tobacco leaf suspension space, thereby reducing the probability of contact between the blades and the bulkhead.

[0030] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the inverted conical ring body reduces its own weight while expanding the open space below, allowing the tobacco leaves to spread out naturally after being suspended, reducing the probability of contact between the leaves and the bulkhead or adjacent leaves, and further reducing mechanical damage and uneven fumigation.

[0031] Compared with existing technologies, the beneficial effects of the dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device provided by this utility model are as follows: This utility model, through the suspension and cooperation of an eccentric gravity ring and ball bearings, converts the energy of "rising hot airflow," which could only complete mass transfer, into kinetic energy to drive the ring rotation, so that the tobacco leaf is in a coupled motion of slow rotation and gravitational oscillation throughout the fumigation process. The blades continuously change the angle of opposition with the airflow, with the back and belly of the blades taking turns becoming the windward side, allowing the fumigant to form a uniform film on both sides, fundamentally eliminating the phenomena of "yin-yang sides" and "adhesive white core"; during the movement, the ash and excess drug droplets attached to the leaf surface slip off due to inertia and are carried by the airflow to settle towards the chamber wall, reducing secondary adhesion and achieving "simultaneous fumigation and cleaning"; the leaf veins obtain stress relaxation similar to "low-temperature breeze drying" in the slight oscillation, the fibers maintain rigidity, and they no longer break due to softness and brittleness during unloading, significantly reducing the mechanical damage rate. Because the entire system lacks fans, motors, gearboxes, or slip rings, and there are no easily corroded electrical components inside the fumigation chamber, routine maintenance only requires rinsing the ring and bearings, significantly reducing maintenance workload. Simultaneously, the system has a wider adaptability range to heat source power; even under conditions of small temperature differences and low flow rates, the eccentric ring can be continuously propelled by a weak upward airflow, maintaining uniform rotation and resulting in significant energy savings. The limiting design of the gap between the annular retaining ring and the conical surface ensures that the ring will not collide with the chamber wall under any operating conditions, resulting in quiet operation. The magnetic leaf clamps eliminate the need for threaded springs, preventing fumigant crystallization and jamming, enabling rapid loading and unloading, and shortening batch changeover time. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 An example diagram of a dual-layer airflow circulating tobacco leaf ash-retaining fumigation device;

[0034] Figure 2 A perspective view of a dual-layer airflow circulating tobacco leaf ash-reducing fumigation device;

[0035] Figure 3 for Figure 2 Enlarged view of section A in the middle;

[0036] The attached diagram lists the components represented by each number as follows:

[0037] 10. Fumigation chamber; 11. Suspension shaft; 20. Eccentric gravity ring; 21. Ball bearing; 22. Magnetic leaf clamp. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0039] like Figures 1-3 The diagram shown is an example of a dual-layer airflow circulating tobacco ash-reducing fumigation device provided by this utility model, comprising:

[0040] The fumigation chamber 10 is equipped with a horizontal suspension shaft 11 at the top;

[0041] An eccentric gravity ring 20 is suspended from a suspension shaft 11 by a ball bearing 21 in a manner that allows it to rotate freely around its own axis. The center of gravity of the eccentric gravity ring 20 is offset relative to its geometric axis, giving the ring a unidirectional rotational tendency under the action of gravitational torque.

[0042] Several magnetic leaf clips 22 are evenly distributed around the ring body in a circumferential direction. The clamping surface of the leaf clips faces the radial inner side of the ring body and are used to fix the tobacco leaves in a hanging manner.

[0043] The bottom of the fumigation chamber 10 is provided with an upward hot airflow channel. The outlet of the hot airflow channel is located below the eccentric gravity ring 20, so that the upward airflow directly impacts the lower edge of the ring and drives the ring to rotate slowly and continuously.

[0044] When the eccentric gravity ring 20 rotates, the tobacco leaves oscillate back and forth under the coupling of gravity and inertia, forming a dynamic fumigation state.

[0045] In the above technical solution, the eccentric gravity ring 20 is a closed ring integrally cast. The wall thickness of the ring changes continuously along the circumference. The area with the largest wall thickness constitutes the center of gravity offset part, and the area with the smallest wall thickness is located on the opposite side of the center of gravity offset part, so that the center of gravity deviates from the geometric axis.

[0046] Furthermore, in the above technical solution, the outer ring of the ball bearing 21 is interference-fitted with the top suspension shaft 11 of the fumigation chamber 10, and the inner ring is interference-fitted with the upper end face protrusion of the eccentric gravity ring 20, so that the ring can rotate freely around the axis without external driving force after suspension.

[0047] Furthermore, in the above technical solution, the magnetic leaf clamp 22 includes a fixed jaw, a movable jaw, and a permanent magnet. The fixed jaw extends integrally with the ring body, the movable jaw is hinged to the fixed jaw via a pivot, and the permanent magnet is embedded between the mating surfaces of the fixed jaw and the movable jaw, forming a boltless quick clamping structure.

[0048] Furthermore, in the above technical solution, the outlet of the rising hot airflow channel of the fumigation chamber 10 is slit-shaped, and the length direction of the slit is parallel to the tangential direction of the annulus, so that the hot airflow uniformly impacts the circumferential area of ​​the lower edge of the annulus in a curtain-like form.

[0049] Furthermore, in the above technical solution, the top wall of the fumigation chamber 10 is provided with a downwardly protruding annular retaining ring. The annular retaining ring is located on the outer periphery of the eccentric gravity ring 20 and maintains a radial gap with the ring body, which is used to limit the radial swing amplitude when the ring body rotates.

[0050] The lower surface of the retaining ring is made into an inner conical surface, and the corresponding section on the outer periphery of the eccentric gravity ring is made into an outer conical surface. The two conical surfaces are coaxial and the smaller ends face upwards, forming an annular wedge-shaped space that is narrower at the top and wider at the bottom. After assembly, the two conical surfaces maintain an equidistant gap in any radial direction. The gap width is determined by the relative axial position of the conical surfaces. The gap size can be changed as a whole by adjusting the axial limiting step of the retaining ring on the suspension shaft, without the need for additional shims. This structure allows the ring to rotate freely, while utilizing the gradually converging characteristics of the wedge-shaped gap to dampen and limit excessive radial oscillations, preventing collisions during operation.

[0051] Furthermore, in the above technical solution, the lower edge of the eccentric gravity ring 20 is provided with circumferentially distributed arc-shaped fins, with the concave surface of the arc-shaped fins facing the direction of the hot airflow, in order to increase the tangential thrust of the airflow on the ring body.

[0052] Furthermore, in the above technical solution, the clamping surface of the magnetic leaf clip 22 is provided with transversely penetrating wavy teeth, which are used to increase the clamping friction and reduce local stress concentration in the leaf veins when the tobacco leaves swing.

[0053] Furthermore, in the above technical solution, the bottom of the fumigation chamber 10 is also provided with a return air loop. The air inlet of the return air loop is located at the lower part of the chamber wall, and the air outlet is located at the entrance side of the hot airflow channel, forming a circulating airflow path from bottom to top, so that the eccentric gravity ring 20 is always surrounded by the rising airflow.

[0054] Furthermore, in the above technical solution, the axial width of the eccentric gravity ring 20 gradually narrows from top to bottom, forming an inverted conical ring, which is used to reduce the self-weight of the ring and increase the radial openness of the tobacco leaf suspension space, thereby reducing the probability of contact between the blade and the bulkhead.

[0055] Example 1: In small-scale tobacco curing barn clusters in hilly production areas, it is common to encounter situations where a single batch of tobacco leaves weighs less than 2,000 kg and there are difficulties in increasing power capacity. This example uses an eccentric gravity ring with an inner diameter of 1,000 mm. The ring body is integrally cast from aluminum alloy with a gradually changing wall thickness, and the center of gravity is offset from the axis by about 5 mm. The top is suspended from the fixed crossbeam of the fumigation chamber by a pair of sealed deep groove ball bearings. The inner ring of the bearing is interference-fitted with the upper end stop of the ring body, and the outer ring is interference-fitted with the hole of the crossbeam, forming a boltless suspension. Two gas-fired infrared plates are placed at the bottom of the chamber, with the combustion surface at a 15-degree angle to the horizontal. The hot gas flow rises along the inclined plate and is then ejected from a 360-degree continuous slit outlet. The slit height is 8 mm, and the upper edge of the outlet maintains a 20-mm axial distance from the lower edge of the ring body. The tobacco leaves are suspended in bundles using stainless steel magnetic clips, with the petioles facing inward and the leaf tips facing downward. The weight of each bundle is controlled at about 80 grams, and 36 bundles are evenly distributed on the ring body, with a total load of about 30 kg. Ten minutes after the gas-fired plate is activated, the ring begins to rotate slowly. The blades are visibly revolving at approximately one revolution per minute, while simultaneously swaying back and forth along their orbital path due to gravity. The gaps between the blade layers open and close periodically, allowing the fumigant to be carried in by the hot airflow and evenly contact the back and underside of the blades. The entire batch process lasts fifty minutes, requiring no external power connection. Dynamic fumigation can be completed solely through the gas-fired heat source and the asymmetrical mass of the structure itself. This method is suitable for point-to-point processing of semi-finished products in mountainous areas with limited power supply and minimal staff. The blades exhibit good rigidity during unloading, and the blade stalks break with a crisp sound, meeting subsequent transportation requirements.

[0056] Example 2: In the continuous production line of the Kunming re-drying plant, the fumigation section needs to be embedded in the chain conveyor system to achieve online processing of batches weighing tens of thousands of kilograms. In this example, the eccentric gravity ring is enlarged to an inner diameter of two meters, and the material is changed to corrosion-resistant austenitic stainless steel. The wall thickness gradient is formed by CNC machining, while the center of gravity deviation remains at five millimeters. The suspension shaft is integrated with the steel structure beam of the production line, and three sets of self-aligning roller bearings are evenly distributed side by side on the shaft. The inner ring of the bearing is heat-fitted onto the shaft, and the outer ring is interference-fitted with the flange on the ring body, which can withstand greater radial loads and automatically align itself, meeting the coaxial requirements under long shaft spans. The heat source at the bottom of the tank is changed to a steam finned heat exchanger with a hot water temperature of 95 degrees Celsius. The surface of the heat exchanger is parallel to the horizontal, and a full ring of annular slit outlets is covered above it. The slit height is ten millimeters, and the upper edge of the slit is thirty millimeters from the lower edge of the ring body. The finned heat exchanger can be started and stopped in stages according to the chain speed to achieve temperature gradient control. Tobacco leaves are suspended in bundles using food-grade magnetic clips, each bundle weighing 100 grams. Sixty bundles are evenly distributed across the ring, with a total load of approximately 120 kilograms. The ring, laden with tobacco leaves, is pushed into the chamber via a ground guide rail, automatically engaging and locking with the suspension shaft. Upon activation of the steam valve, hot air rises along a narrow slit, propelling the ring to rotate at a rate of two revolutions per minute. The leaves sway slightly during this revolution, causing the gaps between the leaf layers to open and close continuously, allowing the fumigant to penetrate evenly with the airflow. The entire chamber is twelve meters long. The ring operates for twenty minutes before automatically detaching from the suspension shaft at the outlet and being delivered via the ground guide rail, seamlessly connecting with the downstream chain plate. This system is suitable for high-volume, standardized re-drying workshops, enabling large-scale dynamic fumigation without shutdown. The entire process requires no additional power input, utilizing only the existing steam heat source within the plant, resulting in significant energy savings.

[0057] Specifically, the principle of this invention is as follows: the geometric axis of the eccentric gravity ring does not coincide with the center of gravity, naturally forming a gravitational torque. When suspended from the top of the cabin by ball bearings, the ring tends to rotate around its axis, but this tendency is balanced by the static friction of the bearings in a static state. The bottom heat source continuously generates rising hot airflow with low density and high buoyancy, preferentially rising along the central axis of the cabin. When it encounters the lower edge of the eccentric gravity ring at the outlet, the airflow is forced to change direction and splits tangentially along the ring. Since the radii from the axis are unequal at various points around the ring, the airflow is more obstructed on the thick-walled side (center of gravity side) and less obstructed on the thin-walled side, thus generating a circumferential thrust difference, which pushes the ring to overcome static friction and begin to rotate. Once rotation starts, the gravitational torque generated by the shift in the center of gravity is in the same direction as the airflow thrust torque, entering a "self-sustaining" state: the ring speed is automatically adjusted according to the strength of the airflow, but always kept in a very low range to avoid excessive centrifugal force causing the blades to fly outward. The tobacco leaves are suspended below the ring by magnetic clamps and move in a uniform circular motion with the ring. Simultaneously, the leaf's own weight always points vertically downwards, continuously forming an angle with the direction of motion, creating a periodic "swinging" tendency. Thus, the leaves exhibit small-amplitude simple harmonic oscillations while revolving. This oscillation causes the gaps between the leaf layers to open and close continuously, resulting in fluctuating cross-sections of the airflow channels and a pulsating penetration effect. Fumigant particles are repeatedly squeezed into the leaf underside contact area, achieving uniform deposition. The oscillation also subjectes the ash adhering to the leaf surface to tangential inertial force. When this force exceeds the adhesion strength, the ash detaches and is carried away by the airflow. Due to the extremely low rotation speed of the ring, the inertial force is just sufficient to peel off the ash without damaging the leaf veins. The inner conical surface of the annular retaining ring and the outer conical surface of the ring form a coaxial wedge-shaped gap. When the ring experiences radial movement due to uneven loading, the gap gradually converges axially, providing flexible damping to the ring and preventing further displacement, thus avoiding metal-on-metal impact. The return air duct utilizes the cavity between the bulkhead and the outer insulation layer to guide the sinking low-temperature gas back to the bottom of the heat source, forming a closed thermodynamic cycle. This ensures the continuous existence of the rising airflow and provides long-term torque for the eccentric ring.

Claims

1. A dual-layer airflow circulating tobacco leaf ash-reducing fumigation device, characterized in that, include: The fumigation chamber is equipped with a horizontal suspension shaft at the top; An eccentric gravity ring is suspended from the suspension shaft by ball bearings in a manner that allows it to rotate freely around its own axis. The center of gravity of the eccentric gravity ring is offset from its geometric axis, giving the ring a unidirectional rotational tendency under the action of gravitational torque. Several magnetic leaf clips are evenly distributed around the ring body, with the clamping surface of the leaf clips facing the radial inner side of the ring body, for fixing tobacco leaves in a suspended manner. The bottom of the fumigation chamber is provided with an upward hot airflow channel. The outlet of the hot airflow channel is located below the eccentric gravity ring, so that the upward airflow directly impacts the lower edge of the ring and drives the ring to rotate slowly and continuously. When the eccentric gravity ring rotates, the tobacco leaves oscillate back and forth under the coupling of gravity and inertia, forming a dynamic fumigation state.

2. The dual-layer airflow circulating tobacco leaf ash-reducing fumigation device according to claim 1, characterized in that, The eccentric gravity ring is a closed ring formed by integral casting. The wall thickness of the ring changes continuously along the circumference. The area with the largest wall thickness constitutes the center of gravity offset part, and the area with the smallest wall thickness is located on the opposite side of the center of gravity offset part, causing the center of gravity to deviate from the geometric axis.

3. The dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device according to claim 2, characterized in that, The outer ring of the ball bearing is interference-fitted with the suspension shaft at the top of the fumigation chamber, and the inner ring is interference-fitted with the protrusion on the upper end face of the eccentric gravity ring, so that the ring can rotate freely around the axis without external driving force after suspension.

4. The dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device according to claim 3, characterized in that, The magnetic leaf clamp includes a fixed jaw, a movable jaw, and a permanent magnet. The fixed jaw extends integrally with the ring body, the movable jaw is pivotally connected to the fixed jaw, and the permanent magnet is embedded between the mating surfaces of the fixed jaw and the movable jaw, forming a boltless quick clamping structure.

5. The dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device according to claim 4, characterized in that, The outlet of the rising hot airflow channel of the fumigation chamber is slit-shaped, with the length of the slit parallel to the tangent of the annulus, so that the hot airflow impacts the lower circumferential area of ​​the annulus in a curtain-like manner.

6. The dual-layer airflow circulating tobacco leaf ash-reducing fumigation device according to claim 5, characterized in that, The top wall of the fumigation chamber is provided with a downward-protruding annular retaining ring. The annular retaining ring is located on the outer periphery of the eccentric gravity ring and maintains a radial gap with the ring body to limit the radial swing amplitude when the ring body rotates.

7. The dual-layer airflow circulating tobacco leaf ash-reducing fumigation device according to claim 6, characterized in that, The lower edge of the eccentric gravity ring is provided with circumferentially distributed arc-shaped fins, the concave surface of which faces the direction of the hot airflow to increase the tangential thrust of the airflow on the ring.

8. The dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device according to claim 7, characterized in that, The magnetic leaf clamp has transversely continuous wavy teeth on its clamping surface, which increases clamping friction and reduces local stress concentration in the leaf veins when the tobacco leaves swing.

9. The dual-layer airflow circulating tobacco leaf ash inhibitor fumigation device according to claim 8, characterized in that, The bottom of the fumigation chamber is also equipped with a return air loop. The air inlet of the return air loop is located at the lower part of the chamber wall, and the air outlet is located at the entrance side of the hot airflow channel, forming a circulating airflow path from bottom to top, so that the eccentric gravity ring is always surrounded by the rising airflow.

10. A double-layer airflow circulating tobacco leaf ash-reducing fumigation device according to claim 9, characterized in that, The axial width of the eccentric gravity ring gradually narrows from top to bottom, forming an inverted conical ring. This is used to reduce the weight of the ring and increase the radial openness of the tobacco leaf suspension space, thereby reducing the probability of contact between the blades and the bulkhead.

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