Laboratory small-sized thin-plate cut-tobacco drier

Abstract

The invention relates to the technical field of tobacco, and discloses a laboratory small-sized thin-plate cut-tobacco dryer which comprises a drying cylinder, the inclination angle of the drying cylinder is adjusted to be 0-5 degrees, the drying cylinder is installed on a base through a pair of bearings, the head of the drying cylinder is connected with a feeding bin through a protective guide groove, and a feeding shifting roller driven by a shifting roller motor is arranged in the feeding bin; a transmission gear ring is annularly arranged on a front end port of the drying cylinder, and is matched with a driving gear to be connected with a driving motor through a speed reducer; a heat transfer gap is reserved between the nanometer heating device and the drying cylinder; a plurality of shoveling plates are fixed on the inner wall of the drying cylinder at equal intervals; and a discharge hole is formed in the tail end surface of the drying cylinder and is connected with a material receiving disc.

Description

Technical Field

[0001] The present invention relates to the field of tobacco technology, and particularly to tobacco processing equipment for laboratories, specifically a small-scale thin-sheet tobacco dryer for laboratories. Background Art

[0002] In the prior art, in laboratory research on tobacco processing, for the laboratory to precisely control the tobacco drying process, a precise drying process that meets the ASTM E2456-06 standard plays a crucial role in ensuring tobacco quality. However, existing tobacco drying equipment has multiple technical defects, severely restricting its performance and application.

[0003] I. Moisture control deviation caused by thermodynamics coupling instability Existing equipment has multiple control disharmonies caused by design defects in the heat conduction mechanism: 1. The uniformity index of the radial temperature field is lower than 0.82 (the ideal value > 0.95), resulting in poor consistency of material heating and affecting the tobacco drying effect; 2. Under unsteady heat transfer conditions, moisture migration shows significant non-linear characteristics. Existing equipment adopts an open-loop control mode and cannot achieve dynamic compensation of the moisture content, resulting in a standard deviation of the finished product moisture content reaching 0.67%, far exceeding the target value of 0.3%. This makes the moisture content of the dried tobacco unstable and difficult to meet the requirements of high-quality tobacco processing.

[0004] II. System efficiency attenuation caused by structural topology redundancy Traditional designs have over-engineering defects: ① The independent air duct system is equipped with redundant axial fans (power ≥ 120W) and flow guiding components, and its system energy efficiency ratio is only 2.1, far lower than the requirement that the standard value of laboratory equipment should be > 3.5. This not only consumes a large amount of energy but also reduces the overall operating efficiency of the equipment; ② The multi-layer sealed end cover structure increases the maintenance complexity index to level 4.2, while the target value of the simplified structure is ≤ 2.5; Experiments show that in a small-scale device with a volume < 50L, such redundant components increase the unit energy consumption by 31% and result in an effective working volume loss rate of 17.5%, reducing the practicality of the equipment.

[0005] The above technical defects severely restrict the applicability of experimental equipment, especially in the research on precise drying processes that need to meet the ASTM E2456-06 standard.

[0006] In the prior art, the research and development achievements of experimental-level micro tobacco drying devices are scarce. An electric heating type tobacco dryer suitable for use in cigarette industry laboratories disclosed in CN2208803Y realizes an electric circuit through a conductive ring, a wiring ring and a carbon brush. The number of carbon brush groups can be selected according to the power supply voltage of the working environment, and the number of electric heating tubes can be determined according to the size of the tobacco drying cylinder. The utility model adjusts the rotation speed of the tobacco drying cylinder at any time with a stepless speed regulation motor, and adjusts the inclination angle of the tobacco drying cylinder by adjusting the bottom plate. However, the device has the following key technical defects: First, there are structural defects in the heat conduction system. The device adopts a direct heating mode with electric heating tubes embedded in the inner wall of the drying cylinder, resulting in a significant gradient difference in the temperature field distribution inside the cylinder. Experimental data shows that this structure will generate large temperature fluctuations during continuous operation, which will affect the stability of material moisture evaporation, resulting in the final moisture content deviation exceeding the standard of ±0.5% required by the process.

[0007] Second, there is a problem of design redundancy in the hot air circulation system. The forced convection moisture exhaust system it adopts includes complex components such as an independent fan, a diversion cover and a sealed end cover. However, the gas production volume (usually less than 0.5 m³ / h) of small-batch tests in the laboratory is far lower than the requirements of industrial-level equipment. Measured data shows that under the simple structure of opening both ends of the drying cylinder, natural convection can achieve a moisture exhaust efficiency of more than 92%, while the existing redundant structure not only increases the energy consumption by 23%, but also causes secondary circulation pollution of miscellaneous gases.

[0008] The above technical defects directly restrict the accuracy of experimental data and the process reproducibility. Especially in laboratory research on materials such as tobacco and medicinal materials with high precision requirements, the existing equipment is difficult to meet the accuracy requirements of the ISO / IEC 17025 standard for experimental devices. Therefore, it is urgent to develop a new thermal system structure to solve the key technical problems of temperature control accuracy and system optimization design. Summary of the Invention

[0009] In order to solve a series of problems existing in the current laboratory tobacco drying device, such as large moisture control deviation, system efficiency attenuation, severely restricting the applicability of experimental equipment, and being difficult to meet experimental requirements, the present invention provides a laboratory small thin-plate tobacco dryer.

[0010] The present invention is realized by adopting the following technical solutions: A small laboratory thin-sheet tobacco dryer includes a drying cylinder. The inclination angle adjustment range of the drying cylinder is ±5°. The drying cylinder is installed on a base through a pair of bearings. The head of the drying cylinder is connected to a feeding bin through a protective feeding chute. A feeding roller driven by a roller motor is provided in the feeding bin; a transmission gear ring is provided around the front end port of the drying cylinder. The transmission gear ring is connected to a driving motor through a reducer in cooperation with a driving gear; a nano heating device is provided on the outer periphery of the drying cylinder and there is a heat transfer gap between the two. A plurality of lifting plates are fixedly arranged at equal intervals on the inner wall of the drying cylinder; an outlet is opened at the end face of the drying cylinder, and the outlet is connected to a receiving tray.

[0011] During implementation, a small laboratory thin-sheet tobacco dryer designed by the present invention includes a drying cylinder. The length-diameter ratio L / d of the drying cylinder is 2 to 5, where L is the length of the drying cylinder and d is the diameter of the drying cylinder. Under this length-diameter ratio, in the laminar flow state where the Reynolds number Re < 2000, the natural convection moisture discharge efficiency can reach 94.6%. The inclination angle adjustment range of the drying cylinder is α = arctan(H / D), where H is the height difference between two feet and D is the distance between the feet installed at both ends of the drying cylinder. The drying cylinder is installed on a base through a pair of bearings. The radial cross-section of the base is circular arc. The two ends of the base are respectively supported by a pair of height-adjustable anchor bolts. By adjusting the height difference of the anchor bolts installed at both ends of the drying cylinder, the inclination degree of the drying cylinder can be adjusted, thereby controlling the drying time of the tobacco shreds. The two bearings are respectively installed at the front section and the end section of the drying cylinder. The head of the drying cylinder is connected to the feeding bin through a protective feeding chute. Specifically, the feeding bin adopts a gravity self-flow feeding bin, which is located at the very front of the entire equipment process and is fixed by bolts. The protective feeding chute is formed by bending 304 stainless steel, connecting the outlet of the feeding bin with the head inlet of the drying cylinder to achieve the sealed transmission of the tobacco shreds, and at the same time, it can protect the test personnel from being injured by the transmission system during operation; A feeding roller driven by a roller motor is provided in the feeding bin. The feeding roller is connected to the roller motor through a coupling. The feeding roller is driven to rotate by the roller motor to achieve quantitative feeding; A transmission gear ring is provided around the front end port of the drying cylinder. The transmission gear ring is connected to a driving motor through a reducer in cooperation with a driving gear. Through the cooperation of the bearings, the rotation of the drying cylinder on the base is achieved; A nano heating device is provided on the outer periphery of the drying cylinder and there is a heat transfer gap between the two. The nano heating device has an annular sleeve structure. The outer diameter of the nano heating device is 240 mm ± 1 mm, and the inner diameter is 124 mm ± 0.5 mm. The nano heating device includes electric heating tubes arranged around the drying cylinder. The electric heating tubes installed in different sections of the drying cylinder are independently temperature-controlled by a temperature control module to achieve uniform heating of the drying cylinder wall. Moreover, gradient temperature control is achieved through the temperature control of the electric heating tubes at different positions of the drying cylinder (such as the three-section distribution method of the front section, the middle section, and the end section, and more segmented control is not limited here); a plurality of lifting plates are fixedly arranged at equal intervals on the inner wall of the drying cylinder to achieve the throwing of the tobacco shreds and ensure that the tobacco shreds in the drying cylinder can fully tumble and be evenly heated; The end face of the drying cylinder is provided with a discharge port, which is connected to the receiving tray.

[0012] During use, the electric heating tube heats the drying cylinder; when the material enters the drying cylinder from the feeding bin through the feeding roller, the driving motor drives the transmission gear ring through the driving gear, and then drives the drying cylinder to rotate. The cut tobacco is heated in sections in the drying cylinder. While the drying cylinder rotates, the lifter plate drives and throws the cut tobacco, and finally enters the receiving tray from the drying cylinder to complete cut tobacco drying.

[0013] Compared with the prior art, the present invention has the following beneficial effects: For the laboratory small thin-plate cut tobacco dryer provided by the present invention, in terms of the heating structure, the electric heating rods are not in contact with the drying cylinder and are evenly distributed around the drying cylinder, constructing a distributed heat source array heating system. This design gets rid of the traditional heat conduction method and innovatively dries the cut tobacco by thermal radiation. With the help of ANSYS thermodynamics simulation, it can be known that the axial temperature uniformity coefficient is greatly increased from 0.82 before improvement to 0.97, forming a more uniform temperature field.

[0014] In terms of the drying cylinder structure design, an open design is adopted, and natural convection is used for moisture discharge, which not only simplifies the drying cylinder structure but also avoids secondary circulation pollution of miscellaneous gases.

[0015] At the system design level, after optimizing the fluid structure, in the laminar flow state where the Reynolds number Re < 2000, the natural convection moisture discharge efficiency can reach 94.6%.

[0016] In summary, this application greatly improves the equipment performance. The energy efficiency ratio of the equipment is increased from 2.1 before improvement to 3.8, and the effective working volume utilization rate reaches 91.3%. While realizing efficient drying of cut tobacco, it greatly improves the utilization rate of energy and space. Description of the Drawings

[0017] Figure 1 It shows the structural schematic diagram of the present invention.

[0018] Figure 2 It shows Figure 1 The cross-sectional view along the A-A direction in

[0019] Figure 3 It shows Figure 2 The cross-sectional view along the B-B direction in

[0020] In the figure: 1 - feeding bin, 2 - feeding roller, 3 - roller motor, 4 - protective guiding trough, 5 - driving motor, 6 - driving gear, 7 - transmission gear ring, 8 - bearing, 9 - receiving tray, 10 - nano heating device, 11 - drying cylinder, 12 - lifter plate, 13 - floor bolt, 14 - base. Detailed Embodiments

[0021] The following describes the specific embodiments of the present invention with reference to the drawings.

[0022] A small laboratory thin-sheet tobacco dryer, as Figure 1 shown: It includes a drying cylinder 11. The specifications of the drying cylinder 11 are length 380 mm × outer diameter 120 mm × wall thickness 2 mm. The length-diameter ratio L / d of the drying cylinder 11 is 3.17. In this embodiment, the inclination angle adjustment range of the drying cylinder 11 is 0 to 5°. The drying cylinder 11 is installed on the base 14 through a pair of bearings 8. The bearings 8 adopt equal-section ultra-thin-wall bearings, with the model k12008 and a thickness of 8 mm. The radial section of the base 14 is an arc, with an arc included angle of 144° ± 2° and a radius of 120 mm ± 0.5 mm. The wall thickness of the base 14 is 5 mm ± 0.2 mm. The two ends of the base 14 are supported by 4 height-adjustable feet 13. The feet 13 adopt M8 adjustable bolts, and the adjustment accuracy is 1.25 mm / rotation. By adjusting the height difference of the feet 13 installed at both ends of the drying cylinder, the inclination degree of the drying cylinder 11 can be adjusted, thereby controlling the baking time of the tobacco shreds. The two bearings 8 are respectively installed at the front section and the tail section of the drying cylinder 11. The head of the drying cylinder 11 is connected to the feeding bin 1 through a protective feeding chute 4. Specifically, the feeding bin 1 adopts a gravity self-flow feeding bin, which is located at the very front end of the entire equipment process and is fixed by bolts. The protective feeding chute 4 is formed by bending 304 stainless steel, connecting the discharge port of the feeding bin 1 with the head inlet of the drying cylinder 11, realizing the sealed transmission of the tobacco shreds, and at the same time protecting the test personnel from being injured by the transmission system during the operation; There is a feeding roller 2 driven by a roller motor 3 in the feeding bin 1. The feeding roller 2 is connected to the roller motor 3 through a coupling. The roller motor 3 drives the feeding roller 2 to rotate. The rotational speed ratio of the feeding roller 2 to the drying cylinder 11 is locked at 4:1 to achieve quantitative feeding; A transmission gear ring 7 is provided around the front end port of the drying cylinder 11. The transmission gear ring 7 is connected to the driving motor 5 through a reducer in cooperation with the driving gear 6. Through the cooperation of the bearings 8, the rotation of the drying cylinder 11 on the base 14 is realized; the module of the gear pair is 1.5, the number of teeth of the driving gear 6 is 40, the number of teeth of the transmission gear ring 7 is 90 ± 1, the interference fit between the transmission gear ring 7 and the drying cylinder 11 is H7 / p6, and the driving motor 5 is a 24V 28-rpm DC reduction motor.

[0023] The outer periphery of the drying cylinder 11 is provided with a nano heating device 10 with a heat transfer gap therebetween. The nano heating device is in the shape of an annular sleeve structure. The outer diameter of the nano heating device 10 is 240 mm ± 1 mm, and the inner diameter is 124 mm ± 0.5 mm. The nano heating device 10 is integrated with a temperature control module, which includes a thermostat, an adjustment panel, a pressure regulator, and a temperature display screen. The adjustment panel can set the temperature range from 20°C to 150°C. The temperature display screen shows the set temperature and the real-time temperature. The PID control program integrated in the thermostat controls the temperature in cooperation with the pressure regulator. The nano heating device 10 includes electric heating tubes arranged around the drying cylinder 11 to achieve uniform heating of the drying cylinder wall. A plurality of lifters 12 are fixedly arranged at equal intervals on the inner wall of the drying cylinder 11. In this embodiment, 5 lifters 12 are provided. The lifters 12 are evenly distributed along the circumferential direction of the drying cylinder, with a height of 10 mm and an inclination angle of 75° ± 1°. The interval between adjacent lifters is 72° ± 0.5°, to achieve the throwing of cut tobacco. In this embodiment, the throwing coverage rate of cut tobacco is ≥ 92%, and the rotation speed is 17 ± 0.3 rpm, ensuring that the cut tobacco in the drying cylinder can fully tumble and be evenly heated. An outlet is opened at the end face of the drying cylinder 11, which is connected to the receiving tray 9. The outer diameter of the receiving tray 9 is 200 mm, the depth is 80 mm, the inclination angle is 64.5°, the edge width is 38 mm, the roughness Ra of the guiding surface is ≤ 0.4 μm, and the edge chamfer is 0.5 mm.

[0024] During use, the electric heating tubes heat the drying cylinder 11. When the material enters the drying cylinder 11 from the feeding bin 1 through the feeding roller 2, the driving motor 5 drives the transmission gear ring 7 through the driving gear 6, and then drives the drying cylinder 11 to rotate. The cut tobacco is heated in sections in the drying cylinder 11. During use, the axial temperature gradient is ≤ 3°C / 100 mm, and the axial temperature uniformity coefficient is 0.97, which greatly improves the axial temperature uniformity coefficient and forms a more uniform temperature field. While the drying cylinder 11 is rotating, the lifters 12 drive and throw the cut tobacco, and finally the cut tobacco enters the receiving tray 9 from the drying cylinder 11 to complete cut tobacco drying. After testing, the moisture difference of the cut tobacco dried by this device is ≤ 0.9%, and the energy consumption ratio is ≤ 0.8 kW•h / kg.

[0025] The scope of protection required by the present invention is not limited to the above specific embodiments. Moreover, for those skilled in the art, the present invention can have various deformations and modifications. Any modification, improvement, and equivalent replacement made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A laboratory small-scale thin-plate silk drying machine, comprising a drying cylinder (11), characterized in that: The inclination angle of the drying cylinder (11) is adjustable within a range of 0 to 5 degrees. The drying cylinder (11) is mounted on a base (14) via a pair of bearings (8). The head of the drying cylinder (11) is connected to a feeding bin (1) via a protective guide trough (4). A feeding roller (2) driven by a roller motor (3) is provided in the feeding bin (1). A transmission gear ring (7) is provided on the front end port of the drying cylinder (11); the transmission gear ring (7) cooperates with the driving gear (6) and is connected to the driving motor (5) via a reducer; The outer periphery of the drying cylinder (11) is provided with a nano-heating device (10) and a heat transfer gap is left between the two, and a plurality of copying plates (12) are fixed on the inner wall of the drying cylinder (11) at equal intervals; The rear end surface of the drying cylinder (11) is provided with a material discharge port, and the material discharge port is connected to the material receiving tray (9).

2. A laboratory small-sized thin plate drying machine according to claim 1, characterized in that: The length-to-diameter ratio L / d of the drying cylinder is 2-5.

3. A laboratory small-sized thin plate drying machine according to claim 1, characterized in that: The nano-heating device is in the form of an annular sleeve structure. The nano-heating device (10) comprises electric heating tubes arranged around a drying cylinder (11). The electric heating tubes installed in different sections of the drying cylinder are independently temperature-controlled by a temperature control module.

4. A laboratory small-sized thin plate drying machine according to claim 3, characterized in that: The nano-heating device (10) has an outer diameter of 240 mm±1 mm and an inner diameter of 124 mm±0.5 mm.

5. The small laboratory thin-plate drying machine according to claim 1, characterized in that: Both ends of the base (14) are supported by a pair of height-adjustable feet (13) respectively.

6. A laboratory small-sized thin plate drying machine according to claim 1, characterized in that: The rotation speed ratio of the feeding roller (2) and the drying cylinder (11) is locked at (1-4):1.

Images