A wind collecting cover of a tobacco sheet redrying machine with uniform wind speed structure

Abstract

The utility model relates to tobacco processing equipment technical field, concretely relates to a tobacco sheet redrying machine wind collecting cover with wind speed uniform structure, the utility model aims at solving the problem of poor moisture uniformity of tobacco sheet caused by uneven return air and wind field imbalance of traditional wind collecting cover. The wind collecting cover includes wind collecting cover main part, conical air uniform device, adjusting mechanism, adjusting mechanism connecting plate, conical air uniform device connecting plate, when working, through the shunt and rectification of conical air uniform device, the return air is realized even. The utility model can stabilize hot air circulation, improve the moisture uniformity of tobacco sheet, and is suitable for multiple working conditions and prevents dust accumulation.

Description

Technical Field

[0001] This utility model relates to the technical field of tobacco processing equipment, specifically to an air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure. Background Technology

[0002] In the re-drying process of tobacco sheets, the hot air circulation system is the core for achieving stable drying and quality: the hot air generated by the heating and air supply device is initially divided by the air distribution plate and then evenly enters the drying area to contact the tobacco sheets, removing moisture through heat exchange; the hot air after interacting with the tobacco sheets (i.e., return air) is recovered by the air collection hood, enters the return air duct, and is then transported back to the heating and air supply device for reheating before participating in the next cycle. Uniform hot air velocity ensures consistent heating of the tobacco sheets and stable moisture evaporation, keeping the moisture content deviation within the allowable range of the process; uneven air velocity will lead to some tobacco sheets being over-dried due to excessive air velocity or under-dried due to insufficient air velocity, seriously affecting the drying quality of the tobacco sheets.

[0003] To improve the initial interaction between hot air and tobacco sheets, existing re-drying machines typically install air distribution plates before the hot air enters the tobacco sheet area. These plates, through the distribution of ventilation holes or structural design, divert and buffer the initial hot air, reducing localized wind speed differences caused by direct impact of hot air on the tobacco sheets and providing a relatively uniform initial airflow environment.

[0004] However, the return air formed after the hot air passes through the smoke sheet will have significant deviations in wind speed and pressure due to the local thickness and density differences of the smoke sheet (which lead to different penetration resistance of the hot air). Due to the structural design defects of the air collecting hood, the air inlet diameter of the air collecting hood is large while the air outlet diameter is small. This causes the airflow to gather in the central area with the least resistance after entering the air collecting hood. As a result, the return air velocity in the central area is too high, while the velocity in the edge area is significantly lower due to insufficient airflow replenishment. The difference in return air velocity between the central area and the edge area can reach about 50%.

[0005] Uneven return air can disrupt the stability of hot air circulation: return air from multiple air collectors with uneven wind speeds merges in the return air duct and then re-enters the heating and air supply components to participate in the circulation. As the airflow imbalance gradually accumulates during the hot air circulation process, even if the initial air supply is adjusted by the air distribution plate, it is difficult to offset the wind speed differences caused by the gradual accumulation of airflow imbalance, ultimately resulting in poor tobacco sheet baking quality that fails to meet processing requirements.

[0006] Therefore, it is urgent to optimize the structure of the air collection hood so that it can guide and distribute the return air, improve the uniformity of the air field in the hot air circulation system, and ensure the stability of the tobacco sheet baking quality. Utility Model Content

[0007] To address the aforementioned issues, this application proposes an air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure. CFD wind field analysis and testing have verified that this effectively improves the aforementioned deficiencies, achieving a uniform wind speed distribution within the air collection hood and ultimately enhancing the quality of tobacco sheet drying.

[0008] To solve the above problems and achieve the above objectives, the present invention adopts the following technical solution:

[0009] A flue gas re-drying machine with a uniform air velocity structure includes a power supply and a control system. The flue gas hood is connected to the air collection pipe of the return air duct of the flue gas re-drying machine. The flue gas hood also includes: a flue gas hood body and a cone-shaped air distribution device.

[0010] The main body of the air collecting hood includes an air inlet and an air outlet. The channel between the air inlet and the air outlet is an exhaust channel. The cross-sectional area of ​​the air inlet is larger than that of the air outlet, so that the hot air passing through the smoke sheet can be recovered and sent into the return air duct.

[0011] The conical air distributor is installed inside the main body of the air collecting hood to uniformly distribute the hot air velocity entering the air collecting hood. The conical air distributor includes an upper cone and a lower cone, and the surface connecting the upper cone and the lower cone is a mating surface. The installation height of the conical air distributor inside the main body of the air collecting hood is adjustable.

[0012] Preferably, the air collecting hood further includes an adjustment mechanism, an adjustment mechanism mounting plate, and a conical air distributor connecting plate; at least two sets of adjustment mechanisms are fixedly or detachably connected to the adjustment mechanism mounting plate; at least two adjustment mechanism mounting plates are symmetrically fixedly connected to the inner side of the air collecting hood body; the conical air distributor connecting plate is threadedly connected to the adjustment mechanism and can move up and down under the drive of the adjustment mechanism; the conical air distributor is fixedly or detachably connected to the conical air distributor connecting plate; the installation height of the conical air distributor within the air collecting hood body can be adjusted by the adjustment mechanism and the conical air distributor connecting plate.

[0013] Preferably, the adjusting mechanism is detachably connected to the adjusting mechanism mounting plate by bolts, and the conical air distributor is fixedly connected to the conical air distributor connecting plate.

[0014] Preferably, the conical air distributor connecting plate is fixedly connected with a slider, at least two sliders are fixedly connected to both sides of the conical air distributor connecting plate respectively, and the conical air distributor connecting plate is threadedly connected to the adjusting mechanism through the sliders.

[0015] Preferably, the adjustment mechanism is a guide rail electric cylinder, which is vertically fixedly connected to the adjustment mechanism mounting plate.

[0016] Preferably, the distance L from the joint surface of the upper and lower cones of the conical air distributor to the end face where the air inlet is located is 300~400mm.

[0017] Preferably, the main body of the air collecting hood is composed of a hollow frustum-shaped hood and a hollow rectangular column-shaped air outlet.

[0018] Preferably, the cone angle X of the upper cone of the conical air distributor is 30~150 degrees.

[0019] Preferably, the cone angle of the lower cone of the conical air distributor is 90 degrees.

[0020] The working principle of this invention is as follows: the multiple facets of the conical air distributor provide multiple flow paths, enabling multi-directional splitting and mixing of the airflow during its flow. The lower cone guides the high-speed airflow from the center outwards, dispersing the concentrated kinetic energy to the edge areas, while the upper cone further rectifyes the airflow, making it more evenly cover the entire surface of the air distribution hood and reducing the wind speed difference between the center and the edge. As the airflow flows from the lower cone to the upper cone, its flow cross-section gradually expands or contracts with the slope of the cone, rather than changing abruptly. This results in a slow pressure change during the flow, rather than a sudden increase or decrease in local pressure. According to Bernoulli's principle, velocity is inversely proportional to pressure, and a stable pressure gradient ensures that the velocity difference of the airflow in different areas is reduced, thereby achieving wind speed uniformity.

[0021] By adjusting the installation height of the cone-shaped air distributor, its position in the exhaust duct can be optimized, thus improving the airflow guidance and distribution effect.

[0022] The beneficial effects of this utility model are:

[0023] 1. This utility model significantly improves the stability of the hot air circulation system. By setting a conical air distributor composed of an upper cone and a lower cone inside the main body of the air collector hood, this utility model solves the problem of air field imbalance during the hot air circulation process caused by local thickness and density differences of tobacco sheets and structural design defects of the air collector hood in traditional tobacco sheet re-drying machines, thereby improving the long-term stability of the hot air circulation system of the tobacco sheet re-drying machine.

[0024] 2. This utility model ensures uniform drying of tobacco sheets and significantly improves baking quality. Because the conical air distributor evens out the return air velocity, the uniform return air is heated by the hot air circulation system and then further evenly distributed by the air distribution plate, providing a stable and uniform airflow field for the tobacco sheets. This ensures consistent heating and a stable moisture evaporation rate during the drying process, resulting in uniform drying and significantly improved baking quality.

[0025] 3. This utility model is flexibly adjustable and adaptable to various working conditions. Through an adjustment mechanism, the installation height of the conical air distributor within the exhaust duct can be adjusted as needed. This allows for optimization of the air distribution range of the conical air distributor when processing conditions such as sheet thickness and density change. It avoids localized air distribution failure caused by excessively close or distant distances, ensuring optimal air distribution under various production conditions.

[0026] 4. This invention has a self-cleaning effect. CFD wind field analysis and testing have verified that the low-speed vortex region formed at the top of the conical air distributor does not interfere with the uniformity of the main airflow, and its low-speed characteristics allow it to blow away light impurities such as dust, preventing dust accumulation from affecting airflow. Attached Figure Description

[0027] Figure 1 This is an installation diagram of this utility model;

[0028] Figure 2 This is a schematic diagram of the hot air circulation in a tobacco sheet re-drying machine;

[0029] Figure 3 This is a schematic diagram illustrating the working principle of this utility model;

[0030] Figure 4 This is one of the schematic diagrams illustrating the installation height of the adjustable conical air distributor of this utility model;

[0031] Figure 5 This is the second side view of the present invention and a schematic diagram of the installation height of the adjustable conical air distributor;

[0032] Figure 6 This is a three-dimensional structural schematic diagram of the present invention (excluding the conical air distributor connecting plate and the conical air distributor).

[0033] Figure 7 This is a three-dimensional structural diagram of the conical air distribution device connecting plate and the conical air distribution device;

[0034] Figure 8 This is a partial structural schematic diagram of the present invention;

[0035] Figure 9 yes Figure 8 A magnified view of part A in the schematic diagram of the partial structure shown;

[0036] Figure 10 This is a vector diagram of the return air velocity on the vertical cross-section of this utility model;

[0037] Reference numerals: 1—Main body of the air collecting hood; 11—Air inlet; 12—Exhaust duct; 13—Air outlet; 2—Conical air distributor; 21—Upper cone; 22—Lower cone; 3—Adjusting mechanism; 31—Motor; 32—Gear; 33—Screw; 4—Adjusting mechanism mounting plate; 5—Conical air distributor connecting plate; 51—Slider; 6—Return air duct; 61—Air collecting duct; 62—Return air collecting duct; 63—Return air duct; 7—Smoke sheet conveyor belt; 8—Smoke sheet; 9—Heating and air supply device; A—Air distribution plate; B—Anemometer. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] Example

[0040] like Figure 1 — Figure 7 The air collection hood of a tobacco sheet re-drying machine with a uniform wind speed structure shown includes a power supply and a control system. The air collection hood is connected to the air collection pipe 61 of the return air pipe 6 of the tobacco sheet re-drying machine. The air collection hood also includes: air collection hood body 1, conical air equalizer 2, adjustment mechanism 3, adjustment mechanism mounting plate 4, and conical air equalizer connecting plate 5.

[0041] like Figure 1 — Figure 6 As shown, the main body 1 of the air collecting hood is composed of a hollow frustum-shaped hood and a hollow rectangular column-shaped air outlet 13. The end of the hood with a larger cross-sectional area is the air inlet 11, and the channel between the air inlet 11 and the air outlet 13 is the exhaust channel 12. The cross-sectional area of ​​the air inlet 11 is larger than that of the air outlet 13, which facilitates the recovery of hot air passing through the smoke sheet and sending it into the return air duct 6. After the return air enters the exhaust channel 12 from the air inlet 11, it gradually contracts along the inner wall of the air collecting hood and flows towards the air outlet 13, reducing airflow diffusion loss.

[0042] like Figure 2 — Figure 7 As shown, the conical air distributor 2 is installed inside the main body 1 of the air collecting hood to uniformly distribute the hot air velocity entering the hood. The conical air distributor 2 includes an upper cone 21 and a lower cone 22, with the surface connecting the upper cone 21 and the lower cone 22 being the mating surface. The distance L from the mating surface of the upper cone 21 and the lower cone 22 to the end face of the air inlet 11 is 300~400mm. Within this range, the installation height will not cause airflow obstruction due to being too close, nor will it weaken the guiding effect due to being too far. The cone angle X of the upper cone 21 of the conical air distributor 2 is designed to be within the range of 30~150 degrees; the cone angle of the lower cone 22 of the conical air distributor 2 is 90 degrees. The lower cone 22 "pushes" the high-speed return air gathered in the central area to the surrounding areas, forcibly dispersing the concentrated kinetic energy to the edge area. The upper cone 21 rectifies the dispersed airflow, allowing the turbulent airflow to smoothly transition along the cone surface, ultimately forming a uniform air field.

[0043] like Figure 2 — Figure 9As shown, there are at least two sets of adjustment mechanisms 3, detachably connected to the adjustment mechanism mounting plate 4; the adjustment mechanism 3 is a guide rail electric cylinder, vertically fixedly connected to the adjustment mechanism mounting plate 4, and the guide rail electric cylinder includes a motor 31, a gear 32, and a lead screw 33. There are at least two adjustment mechanism mounting plates 4, symmetrically fixedly connected to the inner side of the air collecting hood body 1; the conical air distributor connecting plate 5 is threadedly connected to the adjustment mechanism 3 and can move up and down under the drive of the adjustment mechanism 3; the conical air distributor 2 is fixedly connected to the conical air distributor connecting plate 5.

[0044] like Figure 7 — Figure 9 As shown, at least two sliders 51 are fixedly connected to the conical air distributor connecting plate 5, respectively fixedly connected to both sides of the conical air distributor connecting plate 5. The conical air distributor connecting plate 5 is threadedly connected to the lead screw 33 of the adjusting mechanism 3 through the sliders 51. The sliders 51 have internal threads. When the adjusting mechanism 3, i.e. the guide rail electric cylinder, is working, the motor 31 drives the sliders 51 to move vertically up and down along the guide rail through the gear 32 and the lead screw 33. The sliders 51 drive the conical air distributor connecting plate 5 and the conical air distributor 2 fixed on it to move synchronously, thereby adjusting the installation height of the conical air distributor 2 in the air collecting hood body 1.

[0045] In summary, the specific usage process of this utility model is as follows:

[0046] First, CFD wind field analysis and testing were conducted to determine the cone angle X of the cone 21 on the cone-shaped wind distributor, which maximizes the wind distribution effect and creates a low-speed vortex region in the upper part of the cone-shaped wind distributor 2. Figure 10 As shown, the red area in the center of the air collection duct 61 is relatively large and uniform, while the wind speed in the edge area is slightly lower, but the difference from the center area is small, indicating that the wind uniformity effect is good. The low-speed vortex area at the top of the cone-shaped wind uniformizer 2 will not interfere with the wind uniformity effect of the main airflow, and can also use its low-speed characteristics to blow away light impurities such as dust, thus avoiding dust accumulation from affecting the airflow.

[0047] First, install this utility model on the air collection pipe 61 of the return air duct 6. After installation, connect this utility model to the control system and turn on the power.

[0048] Furthermore, based on the real-time data fed back by the anemometer B, the control system drives the motor 31 of the adjustment mechanism 3 (i.e., the guide rail electric cylinder) to move the slider 51 vertically up and down along the guide rail via gear 32 and lead screw 33. The slider 51 drives the conical air distributor connecting plate 5 and the conical air distributor 2 fixed on it to move synchronously, dynamically adjusting their position in the exhaust channel 12. When the thickness of the processed smoke sheet increases, resulting in a low return air velocity, the control system drives the guide rail electric cylinder to raise the height of the conical air distributor 2, increasing the distance between the conical air distributor 2 and the air inlet 11, expanding the buffer and flow space after the return airflow enters, reducing local pressure loss and eddy current loss, thereby reducing the overall airflow resistance and effectively increasing the outlet air velocity. When the thickness of the processed smoke sheet decreases, resulting in a high return air velocity, the control system drives the guide rail electric cylinder to raise the height of the conical air distributor 2, compressing the initial airflow flow space, increasing the resistance of the airflow through the conical area, thereby slowing down the overall airflow speed and controlling the outlet air velocity within a reasonable range.

Claims

1. A flue gas re-drying machine air hood with a uniform wind speed structure, comprising a power supply and a control system, wherein the air hood is connected to the air collection pipe (61) of the return air duct (6) of the flue gas re-drying machine, characterized in that, The air collecting hood also includes: the main body of the air collecting hood (1) and the conical air distribution device (2); The main body (1) of the air collecting hood includes an air inlet (11) and an air outlet (13). The channel between the air inlet (11) and the air outlet (13) is an exhaust channel (12). The cross-sectional area of ​​the air inlet (11) is larger than that of the air outlet (13), so that the hot air passing through the smoke sheet can be recovered and sent into the return air duct (6). The conical air equalizer (2) is installed inside the main body (1) of the air collecting hood to uniformly distribute the hot air velocity entering the air collecting hood. The conical air equalizer (2) includes an upper cone (21) and a lower cone (22). The surface connecting the upper cone (21) and the lower cone (22) is a mating surface. The installation height of the conical air equalizer (2) inside the main body (1) of the air collecting hood is adjustable.

2. The air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 1, characterized in that, The air collection hood also includes an adjustment mechanism (3), an adjustment mechanism mounting plate (4), and a cone-shaped air distributor connecting plate (5); The adjustment mechanism (3) consists of at least two sets, which are fixedly or detachably connected to the adjustment mechanism mounting plate (4); At least two mounting plates (4) of the adjustment mechanism are symmetrically fixed to the inside of the main body (1) of the air collecting hood; The conical air distributor connecting plate (5) is connected to the adjusting mechanism (3) by a thread and can move up and down under the drive of the adjusting mechanism (3). The conical air distributor (2) is fixedly connected to the conical air distributor connecting plate (5) or detachably connected. The installation height of the conical air distributor (2) in the air collecting hood body (1) can be adjusted under the drive of the adjusting mechanism (3) and the conical air distributor connecting plate (5).

3. The air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 2, characterized in that, The adjustment mechanism (3) is detachably connected to the adjustment mechanism mounting plate (4) by bolts, and the conical air distributor (2) is fixedly connected to the conical air distributor connecting plate (5).

4. The air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 2, characterized in that, The conical air distributor connecting plate (5) is fixedly connected to a slider (51). There are at least two sliders (51), which are fixedly connected to both sides of the conical air distributor connecting plate (5). The conical air distributor connecting plate (5) is threadedly connected to the adjusting mechanism (3) through the sliders (51).

5. The air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 2, characterized in that, The adjustment mechanism (3) is a guide rail electric cylinder, which is vertically fixedly connected to the adjustment mechanism mounting plate (4).

6. The air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 1, characterized in that, The distance L from the joint surface of the upper cone (21) and lower cone (22) of the conical air distributor (2) to the end face of the air inlet (11) is 300~400mm.

7. The air collection hood for a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 1, characterized in that, The main body (1) of the air collecting cover is composed of a hollow frustum-shaped cover and a hollow rectangular column-shaped air outlet (13) fixedly connected.

8. The air collection hood of a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 1, characterized in that, The cone angle X of the upper cone (21) of the cone-shaped wind equalizer (2) is 30~150 degrees.

9. The air collection hood of a tobacco sheet re-drying machine with a uniform wind speed structure according to claim 1, characterized in that, The cone angle of the lower cone (22) of the cone-shaped air distribution device (2) is 90 degrees.

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