Vacuum pulsation based tobacco high frequency-vacuum heat treatment method and device

Abstract

The present application relates to a tobacco high-frequency-vacuum heat treatment method and device based on vacuum pulsation, comprising the following steps: after the tobacco is heated to the target temperature by high frequency, it is placed in the vacuum cavity; according to the position of insect damage and the position where the moisture content of the tobacco exceeds the set value, the position of the free end of the vacuum pipe is arranged; according to the insect damage and the moisture content of the tobacco, the pressure, duration and the number of pulsation cycles when the two vacuum stages are alternately performed are set; according to the set pressure, duration and the number of pulsation cycles, the vacuum cavity generates a vacuum environment, and the two vacuum stages are alternately switched to perform high-frequency-vacuum heat treatment. The vacuum pulsation formed by the two vacuum stages with different parameters sets the rapidly changing pressure condition at the position where the insect damage or the moisture content is high, accelerates the dehydration process by vacuum pulsation and kills various forms of pests, and improves the ability of high-frequency-vacuum heat treatment to kill pests.

Description

Technical Field

[0001] This invention relates to the field of tobacco processing technology, specifically to a method and apparatus for high-frequency vacuum heat treatment of tobacco based on vacuum pulsation. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] High-frequency vacuum heat treatment refers to high-frequency heating in a vacuum environment to remove moisture from materials. It utilizes high-frequency (3kHz–300MHz) electromagnetic waves to heat tobacco leaves. The high-frequency energy can penetrate to depths of over 1 meter, raising the internal temperature of the tobacco leaves and achieving dehydration. Compared to traditional heating methods where heat is gradually conducted from the surface to the interior, this method effectively overcomes the drawbacks of low heating efficiency and slow internal temperature rise. The vacuum environment during high-frequency heating lowers the boiling point of water, helping it to convert to vapor at a lower temperature, thus saving energy consumption.

[0004] When processing materials with uneven moisture content, areas with higher moisture content will absorb more electromagnetic energy and achieve higher temperatures within the same heating cycle. Therefore, when dealing with locally damp tobacco leaves, high-frequency vacuum heat treatment can lower the boiling point and promote moisture migration, effectively removing excess moisture and achieving moisture self-balance.

[0005] When insects (eggs) are present in tobacco leaves, high-frequency vacuum heat treatment can be used to utilize the dehydration effect brought by high-frequency energy, combined with the low-temperature environment brought by vacuum to kill some insects (eggs). However, the killing ability of this method is limited, and other processes are usually required to complete the insect control treatment. Summary of the Invention

[0006] To address the technical problems mentioned above, this invention provides a high-frequency vacuum heat treatment method and apparatus for tobacco leaves based on vacuum pulsation. The free end of the vacuum tube is positioned at a location with high moisture content and at a location where pests occur, thereby increasing the treatment intensity. By utilizing the vacuum pulsation formed by two vacuum stages with different parameters, rapidly changing pressure conditions are applied to the location where pests break out or where the moisture content is high. The vacuum pulsation accelerates the dehydration process and effectively kills pests of various forms, thereby enhancing the pest-killing capability of high-frequency vacuum heat treatment.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a high-frequency vacuum heat treatment method for tobacco leaves based on vacuum pulsation, comprising the following steps:

[0009] After the tobacco leaves are heated to the target temperature by high frequency, they are placed in a vacuum chamber;

[0010] The location of the free end of the vacuum tube is determined based on the location of the pest infestation and the location where the moisture content of the tobacco leaves exceeds the set value.

[0011] The pressure and duration of the two vacuum stages, as well as the number of pulsation cycles when the two vacuum stages alternate, are set according to the pest situation and the moisture content of the tobacco leaves.

[0012] The vacuum chamber is made to create a vacuum environment according to the set pressure, duration and number of pulsation cycles, and the two vacuum stages are alternately switched to perform high-frequency vacuum heat treatment. After completion, the tobacco leaves are taken out.

[0013] Furthermore, the target temperature is 50–60°C.

[0014] Furthermore, the locations of pest infestations and areas where the moisture content in the tobacco leaves exceeds a set value are determined through pre-detection of the tobacco leaves before high-frequency heating.

[0015] Furthermore, the two vacuum stages include vacuum stage 1 and vacuum stage 2. The pressure of vacuum stage 1 is -0.09 MPa, the pressure of vacuum stage 2 is -0.03 to -0.05 MPa, the duration of vacuum stage 1 is 3 to 5 minutes, the duration of vacuum stage 2 is 0 to 2 minutes, and the number of pulsation cycles is 2 to 5.

[0016] Furthermore, the position of the free end of the vacuum tube is arranged according to the location of the pest occurrence and the location where the moisture content of the tobacco leaves exceeds the set value. Specifically, when killing pests, the free end of the vacuum tube faces the location of the pest occurrence and is spaced 10-30cm apart; when dehydrating and preventing mold, the free end of the vacuum tube faces the location where the moisture content of the tobacco leaves exceeds the set value and is spaced at the set distance.

[0017] A second aspect of the present invention provides a high-frequency vacuum heat treatment device for tobacco leaves based on vacuum pulsation, comprising a tank, an inlet / outlet on the tank wall, a tobacco box roller table and a uniform airflow duct inside the tank, the tobacco box roller table supporting the tobacco box, the tobacco box being used to hold the tobacco leaves to be treated; the uniform airflow duct is connected to the inlet / outlet and a vacuum tube respectively, one end of the vacuum tube being connected to the uniform airflow duct, and the other end being a free end, the free end being arranged at the location where the tobacco leaves are infested by insects or at the location where the moisture content of the tobacco leaves exceeds a set value.

[0018] Furthermore, the air distribution duct is installed on the main pipeline extending from the inlet / outlet into the tank.

[0019] Furthermore, one end of the vacuum tube is connected to each interface of the equalization duct, while the other end is a free end.

[0020] Furthermore, the air inlet / outlet includes an air inlet and an air outlet, and corresponding control valves are provided on the air inlet and the air outlet.

[0021] Furthermore, the air outlet is connected to a vacuum pump unit via a pipe.

[0022] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0023] By placing the free end of the vacuum tube in locations with high moisture content and pest infestations, the treatment intensity is increased. By utilizing the vacuum pulsation formed by two vacuum stages with different parameters, the rapidly changing pressure conditions are set in areas with outbreaks of pests or high moisture content. The vacuum pulsation accelerates the dehydration process and effectively kills pests of various forms, thereby enhancing the pest-killing ability of high-frequency vacuum heat treatment. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the human metabolic rate prediction process provided by one or more embodiments of the present invention;

[0026] Figure 2 This is a schematic diagram of the architecture of a human metabolic rate prediction device provided in one or more embodiments of the present invention.

[0027] In the diagram: 1. Vacuum chamber; 2. Air inlet / outlet; 3. Flow equalization duct; 4. Metal bellows; 5. Smoke box roller table; 6. Smoke box. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0030] As described in the background section, the high-frequency vacuum heat treatment method absorbs more electromagnetic energy at locations with higher moisture content when processing materials with uneven moisture content. Higher temperatures can be obtained within the same heating cycle. The vacuum environment can lower the boiling point and promote moisture migration, effectively removing excess moisture and achieving moisture self-balance.

[0031] However, when there are insects (eggs) in the tobacco leaves, the high-frequency vacuum heat treatment method has limited killing ability and usually requires other processes to complete the insect removal treatment. Therefore, it is necessary to improve the killing ability of existing high-frequency vacuum heat treatment methods for insects (eggs).

[0032] The following embodiments provide a method and apparatus for high-frequency vacuum heat treatment of tobacco leaves based on vacuum pulsation. The tobacco leaves (tobacco leaves) after high-frequency heating are placed into a vacuum chamber. The position of the free end of the vacuum tube is adjusted according to the predetermined high moisture content location and insect (egg) location. Depending on the insect damage and the moisture content of the tobacco leaves, two vacuum stages with different pressures and durations are alternately performed. The resulting vacuum pulsation can apply rapidly changing air pressure around the insects (eggs), which has a "bursting" effect and a dehydration effect on the insects (eggs), thereby effectively killing pests at a relatively low material temperature.

[0033] Example 1:

[0034] The high-frequency vacuum heat treatment method for tobacco leaves based on vacuum pulsation includes the following steps:

[0035] S1 places the tobacco leaves, which have been heated to the target temperature (50-60°C) by high frequency, into the vacuum chamber;

[0036] S2 determines the placement of the free port of the vacuum tube based on the location of the insect (egg) and the location of the tobacco leaf with high moisture content;

[0037] S3 sets the pressure and duration of vacuum stage 1 and vacuum stage 2 based on the pest situation and tobacco leaf moisture content, and sets the number of pulsation cycles.

[0038] S4 starts the vacuum pump unit, and alternates between two vacuum stages according to the set pressure, duration and number of pulse cycles to start the high-frequency vacuum dehydration and insect (egg) killing treatment;

[0039] After the S5 heat treatment is completed, the tobacco leaves are removed from the vacuum chamber.

[0040] In this embodiment, as Figure 1 As shown, the high-frequency heated tobacco leaves are loaded into the tobacco box 6. The vacuum chamber 1 is a tank with inlet / outlet ports 2 on its wall. Inside, there is a tobacco box roller table 5 and a uniform air duct 3. The tobacco box roller table 5 supports the tobacco box 6. The uniform air duct 3 is connected to the inlet / outlet ports 2 and the vacuum tube respectively. The vacuum tube can be a metal corrugated pipe 4. An external vacuum pump group generates a vacuum and extracts the gas in the vacuum chamber 1 through the uniform air duct 3 and the vacuum tube to form a vacuum environment with a certain pressure.

[0041] In this embodiment, the air inlet / outlet 2 includes an air inlet and an air outlet, each equipped with a corresponding control valve. By opening and closing these control valves, the negative pressure generated by the vacuum pump unit is controlled to extract the gas from the vacuum chamber 1 through the equalization duct 3 and the vacuum tube, or external atmospheric air is controlled to be introduced into the vacuum chamber 1 through the equalization duct 3 and the vacuum tube, thereby balancing the internal and external pressures and allowing the tobacco leaves to be removed. The structure of the air inlet / outlet 2 is a conventional design and will not be described in detail in this embodiment.

[0042] Preferably, the flow equalization duct is set in the main duct extending inward from the vacuum chamber inlet / outlet.

[0043] Preferably, one end of the vacuum tube (in this embodiment, a metal corrugated tube) is connected to each interface of the flow equalization duct, and the other end is placed as a free end.

[0044] Preferably, the free end needs to be placed in a location where pests are rampant or where the moisture content is high, so that the pressure / density changes generated by the free end can enhance the dehydration and insecticidal (egg-killing) effects.

[0045] In this embodiment, the location of the insects (eggs) can be determined by opening and inspecting the smoke box. The specific inspection process is existing technology and will not be described in detail in this embodiment.

[0046] In this embodiment, a microwave online detection device is used to measure the moisture content of tobacco leaves and determine the location where the moisture content of the tobacco leaves is higher than the set value. The specific detection process is existing technology and will not be described in detail in this embodiment.

[0047] In step S2, the placement position of the free port of the vacuum tube is determined according to the location of the insect (egg) and the location of the tobacco leaves with high moisture content. Specifically, assuming that the insect (egg) is located at the top of the tobacco box and the tobacco leaves with high moisture content are located at the bottom of the tobacco box, the free port of the metal corrugated tube is placed at the top of the tobacco box when killing the insect (egg), and at the bottom of the tobacco box when dehydrating and preventing mold.

[0048] Preferably, the pressure of vacuum stage 1 is usually -0.09 MPa, the pressure of vacuum stage 2 is usually -0.03 to -0.05 MPa, and the time of vacuum stage 1 is set to 3 to 5 minutes and the time of vacuum stage 2 is set to 0 to 2 minutes, depending on the degree of pest infestation and the moisture content of tobacco leaves. The number of pulsation cycles is 2 to 5.

[0049] The vacuum level of the equipment is -0.09 MPa in vacuum stage 1. The lower the vacuum level, the better the effect for insecticidal and dehydrating purposes. Vacuum stage 2 is set to -0.03 to -0.05 MPa. This is based on the vacuuming efficiency and is designed to meet the requirements of vacuum pulsation. A portion of the pressure is released before returning to the vacuum environment, thereby achieving an explosion effect around the insects (eggs) and breaking the water vapor equilibrium state inside the material. The above two vacuum levels are the preferred ranges derived from experience.

[0050] In this embodiment, it is assumed that the pest infestation occurs on the surface of the tobacco box, and the moisture content of the bottom tobacco leaves is 3 percentage points higher than the normal value. Therefore, the pressure of vacuum stage 1 is set to -0.09 MPa (the ultimate vacuum pressure of the vacuum pump) and the holding time is 3 minutes. The pressure of vacuum stage 2 is set to -0.04 MPa (half the ultimate vacuum pressure of the vacuum pump) and the holding time is 1 minute. The two vacuum stages are cycled. Each cycle of vacuum stage 1 and vacuum stage 2 is considered to be a complete pulse cycle. The number of pulse cycles is set to 3. The order of vacuum stage 1 and vacuum stage 2 is not restricted. Generally, the vacuum stage with the lower pressure is given priority. That is: start the vibration pump group to reach vacuum stage 2 (pressure -0.04 MPa), hold for 1 minute, switch to vacuum stage 1 (pressure -0.09 MPa), hold for 3 minutes to complete one pulse cycle, and switch to vacuum stage 2. This process is repeated until 3 pulse cycles are completed.

[0051] Based on experimental tests, the dehydration and insecticidal effects of each of the above steps are as follows:

[0052] Before the experiment, select a tobacco box with a high moisture content of tobacco leaves at the bottom after it has been damp, and place a non-woven bag containing tobacco beetles and insect eggs in the top cover to simulate the location of the pests.

[0053] During the experiment, the tobacco leaf temperature and cavity pressure were as follows: Figure 2 As shown;

[0054] After the experiment was completed, the smoke box was removed, the top cover was opened and the non-woven bag containing the pests was taken out. The pests were cultured in a constant temperature and humidity chamber for 7 days, and the activity status of the insects (eggs) was checked. The experimental data are shown in Table 1.

[0055] Table 1: Tobacco leaf moisture content and pest survival rate before and after the experiment

[0056]

[0057]

[0058] Based on the experimental results, it is believed that the above method, by placing the free end of the vacuum tube at locations with high moisture content and pest infestations, combined with vacuum pulsations formed by setting different vacuum pressures, durations, and alternation numbers, creates rapidly changing pressure conditions at locations with outbreaks of pests or high moisture content. This vacuum pulsation accelerates the dehydration process and effectively kills pests of various forms. The position of the free end of the vacuum tube increases the treatment intensity, thereby enhancing the pest-killing ability of high-frequency vacuum heat treatment.

[0059] Example 2:

[0060] A high-frequency vacuum heat treatment device for tobacco leaves based on vacuum pulsation includes:

[0061] The tank body has a vacuum chamber 1 inside, and an air inlet / outlet 2 is provided on the tank body wall. The tank body is equipped with a smoke box roller table 5 and a uniform air duct 3. The smoke box roller table 5 supports the smoke box 6, which is used to hold the tobacco leaves to be processed.

[0062] The equal flow duct 3 is connected to the air inlet / outlet 2 and the vacuum tube respectively. The vacuum tube can be a metal corrugated pipe 4, with one end connected to each interface of the equal flow duct 3 and the other end as a free end, placed at the location where tobacco leaves are infested by pests or where the moisture content of tobacco leaves exceeds the set value.

[0063] This embodiment is the device required to implement Embodiment 1. The vacuum pump group generates a vacuum, and the gas in the vacuum chamber 1 is extracted through the equal flow duct 3 and the vacuum tube to form a vacuum environment with a set pressure. The rapidly changing pressure conditions are set in the area where pests break out or where the moisture content is high. The vacuum pulsation is used to accelerate the dehydration process and effectively kill pests of various forms. The position of the free end of the vacuum tube is used to increase the treatment intensity, thereby improving the ability of high frequency-vacuum heat treatment to kill pests.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-frequency vacuum heat treatment method for tobacco leaves based on vacuum pulsation, characterized in that, Includes the following steps: After the tobacco leaves are heated to the target temperature by high frequency, they are placed in a vacuum chamber; The position of the free end of the vacuum tube is determined based on the location of the pest infestation and the location where the moisture content of the tobacco leaves exceeds the set value. Specifically, during pest control, the free end of the vacuum tube is positioned towards the location of the pest infestation at a set distance; during dehydration and mold prevention, the free end of the vacuum tube is positioned towards the location where the moisture content of the tobacco leaves exceeds the set value at a set distance. The pressure and duration of the two vacuum stages, as well as the number of pulsation cycles when the two vacuum stages alternate, are set according to the pest situation and the moisture content of the tobacco leaves. The vacuum chamber is made to create a vacuum environment according to the set pressure, duration and number of pulsation cycles, and the two vacuum stages are alternately switched to perform high-frequency vacuum heat treatment. After completion, the tobacco leaves are taken out. The two vacuum stages include vacuum stage 1 and vacuum stage 2. The pressure of vacuum stage 1 is -0.09 MPa, and the pressure of vacuum stage 2 is -0.03 to -0.05 MPa. The duration of vacuum stage 1 is 3 to 5 minutes, and the duration of vacuum stage 2 is 0 to 2 minutes. The number of pulsation cycles is 2 to 5.

2. The high-frequency vacuum heat treatment method for tobacco leaves based on vacuum pulsation as described in claim 1, characterized in that, The target temperature is 50~60℃.

3. The high-frequency vacuum heat treatment method for tobacco leaves based on vacuum pulsation as described in claim 1, characterized in that, The location of pest infestation and the location where the moisture content of the tobacco leaves exceeds the set value are determined by pre-detection of the tobacco leaves before high-frequency heating.

4. An apparatus for implementing the high-frequency vacuum heat treatment method for tobacco leaves as described in any one of claims 1-3, characterized in that, The device includes a tank with inlet / outlet ports on its walls. Inside the tank, there is a smoke box roller table and a uniform air duct. The smoke box roller table supports the smoke box, which is used to hold the tobacco leaves to be processed. The uniform air duct is connected to the inlet / outlet ports and a vacuum tube. One end of the vacuum tube is connected to the uniform air duct, and the other end is a free end. The free end is placed at the location where the tobacco leaves are infested with pests or where the moisture content of the tobacco leaves exceeds a set value.

5. The high-frequency vacuum heat treatment apparatus for tobacco leaves based on vacuum pulsation as described in claim 4, characterized in that, The airflow equalization duct is installed on the main pipeline extending from the inlet / outlet into the tank body.

6. The high-frequency vacuum heat treatment apparatus for tobacco leaves based on vacuum pulsation as described in claim 4, characterized in that, One end of the vacuum tube is connected to each interface of the flow equalization duct, and the other end is a free end.

7. The high-frequency vacuum heat treatment apparatus for tobacco leaves based on vacuum pulsation as described in claim 4, characterized in that, The air inlet / outlet includes an air inlet and an air outlet, and corresponding control valves are provided on the air inlet and air outlet.

8. The high-frequency vacuum heat treatment apparatus for tobacco leaves based on vacuum pulsation as described in claim 7, characterized in that, The air outlet is connected to a vacuum pump unit via a pipe.

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