Plasma sterilization packaging device for agricultural products and use method thereof

Abstract

The present invention provides a plasma sterilization packaging device for agricultural products and a method for using the same, which belongs to the technical field of agricultural product preservation and storage, and includes a feeding unit and a packaging unit, wherein the packaging unit includes a first conveyor belt, a packaging conveyor belt, and a second conveyor belt, wherein a roll film is arranged at the lower side of the first conveyor belt, a roll film adjustment device and an upper sealing device are arranged at the upper side of the packaging conveyor belt, and a cutting and sealing device is arranged between the packaging conveyor belt and the second conveyor belt; the upper sealing device is fixedly connected to both sides of the packaging conveyor belt through a first mounting frame, a hot pressing roller is arranged at the lower side of the first mounting frame, and a sealing positioning wheel is arranged at the side of the hot pressing roller close to the roll film, and a plasma processing unit is connected to one side of the sealing positioning wheel. The present invention adopts the above-mentioned plasma sterilization packaging device for agricultural products and a method for using the same, which can solve the problems of long time used for plasma sterilization of agricultural products and secondary contamination during packaging.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural product preservation and storage, and in particular to a plasma sterilization packaging device for agricultural products and a use method thereof. Background Art

[0002] At present, the methods of plasma sterilization and preservation for agricultural products are mainly divided into two categories:

[0003] 1. Sterilize first and then package. This method is to sterilize the food in the ionization area and then package it. This method has a good sterilization effect, but the efficiency is low. It is usually necessary to maintain the food in the ionization area for several minutes to achieve a thorough sterilization effect. In addition, secondary pollution is easily caused during the packaging process. For example, the patent with publication number CN116138471A discloses a food sterilization device with a low-frequency, high-voltage pulsed electric field and cold plasma. The device delivers the sample to be processed to the electrode plate processing area via a conveyor belt, sterilizes it for a period of time, and then packages it. However, the single plasma treatment time is not less than 120 seconds, which is long.

[0004] 2. Pack first and then sterilize. This method avoids the pollution caused by secondary packaging, but due to the presence of packaging materials, the sterilization effect of plasma will be weakened and the processing time will be extended accordingly. For example, the patent with publication number CN112753750A discloses a method for cold sterilization of ready-to-eat dried fruit foods using high-voltage electric field and low-temperature plasma. This method is to place the packaged ready-to-eat dried fruits between two electrode plates and perform intermittent multiple cycles of sterilization treatment. The single processing time is 120 seconds, with an interval of 30 seconds, repeated 3 to 5 times, the treatment effect is better, and it can almost completely sterilize, but the whole process takes a long time.

[0005] Although plasma technology is effective in sterilizing and preserving food, it still faces some limitations in actual production due to the long processing time. Therefore, there is an urgent need for a sterilization and packaging device that can solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a plasma sterilization packaging device for agricultural products and a method of using the same, which can solve the problem of agricultural products taking too long to be sterilized by plasma and the problem of secondary contamination during the packaging process.

[0007] To achieve the above-mentioned object, the present invention provides a plasma sterilization packaging device for agricultural products, comprising a feeding unit and a packaging unit arranged on one side of the feeding unit;

[0008] The packaging unit comprises a first conveyor belt, a packaging conveyor belt and a second conveyor belt, a film roll adjustment device and an upper sealing device are arranged on the upper side of the packaging conveyor belt, a film roll is arranged on the lower side of the first conveyor belt, and a cutting and sealing device is arranged between the packaging conveyor belt and the second conveyor belt;

[0009] The upper sealing device is fixedly connected to both sides of the packaging conveyor belt through a first mounting frame, a hot pressing roller is arranged at the lower side of the first mounting frame, a sealing positioning wheel is arranged at a side of the hot pressing roller close to the roll film, and a plasma processing unit is also connected to one side of the sealing positioning wheel;

[0010] The cutting and sealing device comprises a second mounting frame, the second mounting frame is provided with a through hole, the through hole is sleeved in the middle of the second conveyor belt and the packaging conveyor belt, and the upper and lower parts of the through hole are connected to a guillotine through a push rod;

[0011] A gap is left between the first conveyor belt and the packaging conveyor belt, and a gap is also left between the packaging conveyor belt and the second conveyor belt.

[0012] Preferably, the loading unit comprises a loading conveyor belt, a plurality of baffles are arranged at equal intervals on the loading conveyor belt, a cavity is formed between every two adjacent baffles, and the bottom of the loading conveyor belt is fixed to the ground by supporting legs.

[0013] Preferably, the first conveyor belt is connected to the loading unit via a transition plate.

[0014] Preferably, the upper surfaces of the first conveyor belt, the packaging conveyor belt and the second conveyor belt are located in the same horizontal plane, and the height of the horizontal plane where the first conveyor belt is located is lower than the height of the horizontal plane where the loading conveyor belt is located.

[0015] Preferably, the roll film is arranged on a reel, and two sides of the reel are fixedly connected to two sides of a packaging conveyor belt via connecting strips.

[0016] Preferably, the hot pressing roller and the sealing positioning wheel are at the same height, a heating plate is arranged inside the hot pressing roller, and rolling patterns are arranged on the surface of the hot pressing roller.

[0017] Preferably, the guillotine is provided with heat pressing blocks on both sides and a cutting knife in the middle, and a heating plate is arranged inside the heat pressing block.

[0018] Preferably, the plasma processing unit includes a plasma generator, a power regulator and a gas supply device, the plasma generator is a coaxial dual-dielectric barrier reactor, the power regulator is a modulated pulse power supply, the output voltage is 0~30KV, the output frequency is 5~20KHz, the gas supply device is one of a gas cylinder or a gas generator, and the gas provided by the gas supply device is one or more of air, nitrogen, oxygen, and argon.

[0019] Preferably, the upper interface of the plasma generator is a gas output interface, and the gas output interface is fixed in front of the sealing positioning wheel through an air duct. The lower interface of the plasma generator is a gas input interface, and the gas input interface is connected to the output port of the gas supply device through an air duct. The power regulator is electrically connected to the plasma generator.

[0020] The present invention also provides a method for using the plasma sterilization packaging device for agricultural products as described above, comprising the following steps:

[0021] S1. First, pull out the roll film and pull it upward to the gap between the first conveyor belt and the packaging conveyor belt; then pull the roll film backward and pass both sides of the roll film through the roll film adjustment device, which bends the roll film inward to form a curved roll film; continue to pull the curved roll film backward to overlap both sides; pass the overlapping part through the sealing positioning wheel and then through the hot pressing roller, which heat-presses the overlapping part of the roll film to form a cylindrical shape with openings at both ends;

[0022] S2. Turn on the gas supply device and plasma generator, adjust the output voltage between 0~30KV, the output frequency between 5~20KHz, and turn on all conveyor belts at the same time;

[0023] S3, placing the weighed packaged items to be sterilized into the cavity of the loading unit;

[0024] S4. The packaged items to be sterilized pass through the first conveyor belt into the roll film filled with plasma gas. As the roll film continues to move backward, it passes through the cutting and sealing device and is sealed in the roll film under the action of the upper and lower guillotines to form a single independent sealed bag.

[0025] Therefore, the present invention adopts the above-mentioned plasma sterilization packaging device for agricultural products and the use method thereof, and the beneficial technical effects are as follows:

[0026] (1) The present invention sterilizes agricultural products and foods by directly introducing plasma gas into the packaging, without affecting the subsequent packing process. Compared with the traditional method of "sterilizing first and then packaging" or "packaging first and then sterilizing", the processing time is significantly reduced and the production efficiency is improved.

[0027] (2) The present invention performs plasma sterilization during the packaging process, which effectively avoids the risk of secondary contamination compared to the "sterilization before packaging" method, and further ensures the safety and hygiene of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of a plasma sterilization packaging device for agricultural products according to an embodiment of the present invention;

[0029] Figure 2 It is a partial enlarged view of an upper sealing device of a plasma sterilization packaging device for agricultural products according to an embodiment of the present invention;

[0030] Figure 3 It is a partial enlarged view of a cutting and sealing device of a plasma sterilization packaging device for agricultural products according to an embodiment of the present invention;

[0031] Figure 4 is a graph showing the relationship between the output voltage intensity and the number of bacterial colonies in the second embodiment of the present invention;

[0032] Figure 5 This is a graph showing the relationship between the production cycle and the number of colonies in Example 3 of the present invention.

[0033] Reference numerals

[0034] 1. Loading unit; 11. Loading conveyor belt; 12. Baffle; 13. Support leg; 2. Packaging unit; 21. First conveyor belt; 22. Transition plate; 23. Packaging conveyor belt; 24. Film roll; 25. Film roll adjustment device; 26. Sealing positioning wheel; 27. Hot pressing roller; 28. Guillotine; 29. ​​Push rod; 210. Hot pressing block; 211. Cutting knife; 212. Second conveyor belt; 3. Plasma processing unit; 31. Plasma generator; 32. Gas output interface; 33. Gas input interface; 34. Air duct. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0036] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0037] Embodiment 1

[0038] like Figure 1-Figure 3 As shown, the present invention provides a plasma sterilization packaging device for agricultural products, comprising a feeding unit 1 and a packaging unit 2 arranged on one side of the feeding unit 1;

[0039] The feeding unit 1 comprises a feeding conveyor belt 11 , on which a plurality of baffles 12 are evenly spaced, a cavity is formed between every two adjacent baffles 12 , and the bottom of the feeding conveyor belt 11 is fixed to the ground via supporting legs 13 .

[0040] The first conveyor belt 21 is connected to the loading unit 1 via a transition plate 22 .

[0041] The packaging unit 2 includes a first conveyor belt 21, a packaging conveyor belt 23, and a second conveyor belt 212. A gap is left between the first conveyor belt 21 and the packaging conveyor belt 23, and a gap is also left between the packaging conveyor belt 23 and the second conveyor belt 212. The upper surfaces of the first conveyor belt 21, the packaging conveyor belt 23, and the second conveyor belt 212 are located in the same horizontal plane, and the height of the horizontal plane where the first conveyor belt 21 is located is lower than the height of the horizontal plane where the feeding conveyor belt 11 is located.

[0042] A film roll adjustment device 25 and an upper sealing device are provided on the upper side of the packaging conveyor belt 23, a film roll 24 is provided on the lower side of the first conveyor belt 21, and a cutting and sealing device is provided between the packaging conveyor belt 23 and the second conveyor belt 212;

[0043] The roll film 24 is arranged on a reel, and two sides of the reel are fixedly connected to two sides of the packaging conveyor belt 23 through connecting strips.

[0044] The film roll adjustment device is a thin plate, which is perpendicular to the packaging conveyor belt 23 and has a certain angle with the side surface. The end of the thin plate close to the entrance of the packaging conveyor belt 23 is rounded, and a cylinder is provided at the other end. The cylinder is parallel to the thin plate and there is a certain gap between them. The film roll adjustment device is a prior art and will not be described in detail here.

[0045] The upper sealing device is fixedly connected to both sides of the packaging conveyor belt 23 through a first mounting frame, a hot pressing roller 27 is arranged on the lower side of the first mounting frame, a sealing positioning wheel 26 is arranged on the side of the hot pressing roller 27 close to the roll film 24, the hot pressing roller 27 and the sealing positioning wheel 26 are at the same height, a heating plate is arranged inside the hot pressing roller 27, and a rolling pattern is arranged on the surface of the hot pressing roller 27.

[0046] The cutting and sealing device includes a second mounting frame, which is provided with a through hole, which is sleeved in the middle of the second conveyor belt 212 and the packaging conveyor belt 23, and the upper and lower parts of the through hole are connected to the guillotine 28 through the push rod 29; the guillotine 28 is provided with a hot pressing block 210 on both sides, a cutting knife 211 in the middle, and a heating plate is provided inside the hot pressing block 210. The gap between the second conveyor belt 212 and the packaging conveyor belt 23 is on the same vertical line as the guillotine 28.

[0047] A plasma processing unit 3 is also connected to one side of the sealing positioning wheel 26; the plasma processing unit 3 includes a plasma generator 31, a power regulator and a gas supply device, the plasma generator 31 is a coaxial dual-medium barrier reactor, the power regulator is a modulated pulse power supply, the output voltage is 0~30KV, the output frequency is 5~20KHz, the gas supply device is one of a gas cylinder or a gas generator, and the gas provided by the gas supply device is one or more of air, nitrogen, oxygen, and argon.

[0048] The upper interface of the plasma generator 31 is a gas output interface 32, which is fixed in front of the sealing positioning wheel 26 through an air duct 34. The lower interface of the plasma generator 31 is a gas input interface 33, which is connected to the output port of the gas supply device through an air duct 34. The power regulator is electrically connected to the plasma generator 31.

[0049] Embodiment 2

[0050] This embodiment adopts the rapid plasma sterilization packaging device in the first embodiment. Under the premise of ensuring that the production cycle of the assembly line is 20 seconds and the plasma output frequency is 50 Hz, the experiment is carried out by changing the intensity of the output voltage. The specific steps are as follows:

[0051] 1. Pack the processed but unpackaged dried oranges into 50g portions and store them in an incubator at 35℃~40℃ and 20%~30% relative humidity for 5 days;

[0052] 2. Put the stored dried oranges into the device of Example 1, and use different output voltages (0KV, 5KV, 10KV, 15KV, 20KV, 25KV, 30KV) for plasma treatment and then package them. The packaged dried oranges are stored in an environment with a temperature of 15-25°C for 2 days;

[0053] 3. After 2 days of storage, the dried oranges treated with different voltages and those not treated with plasma were tested for colony count in accordance with "GB 4789.2-2022 National Food Safety Standard Food Microbiology Inspection Colony Count Determination".

[0054] The results are as follows Figure 4 As shown in the figure, the number of microorganisms in the dried oranges treated with plasma is significantly reduced, and the number of colonies gradually decreases with the increase of output voltage intensity. When the output voltage reaches 20KV, the trend of the reduction of the number of colonies tends to be slow.

[0055] Embodiment 3

[0056] The difference between this embodiment and the second embodiment is that in this embodiment, the output voltage is fixed at 20KV, and its influence is studied by adjusting the production cycle. The specific operation steps are as follows:

[0057] 1. Pack the processed but unpackaged dried oranges into 50g portions and store them in an incubator at 35℃~40℃ and 20%~30% relative humidity for 5 days;

[0058] 2. The stored dried oranges were placed in the device of Example 1, and were treated with plasma at different production cycles (10 seconds, 15 seconds, 20 seconds, 25 seconds, and 30 seconds) and packaged. The packaged dried oranges were stored in an environment with a temperature of 15-25° C. for 2 days;

[0059] 3. After 2 days of storage, the dried oranges processed at different production rhythms were tested for colony count in accordance with "GB 4789.2-2022 National Food Safety Standard Food Microbiology Inspection Colony Count Determination".

[0060] The results are as follows Figure 5 As shown in the figure, with the extension of the production cycle, that is, the increase of plasma treatment time, the number of colonies in the dried orange gradually decreased. When the production cycle reached 20 seconds, the trend of the reduction of the number of colonies began to slow down.

[0061] Therefore, the present invention adopts the above-mentioned plasma sterilization packaging device for agricultural products and its use method, which reduces the processing time, improves production efficiency, avoids the risk of secondary contamination, and further ensures the safety and hygiene of the product compared with the traditional method of "sterilization first and then packaging" or "packaging first and then sterilization".

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A plasma sterilization packaging device for agricultural products, characterized in that: It includes a feeding unit and a packaging unit arranged on one side of the feeding unit; The packaging unit comprises a first conveyor belt, a packaging conveyor belt and a second conveyor belt, a roll film is arranged on the lower side of the first conveyor belt, a roll film adjustment device and an upper sealing device are arranged on the upper side of the packaging conveyor belt, and a cutting and sealing device is arranged between the packaging conveyor belt and the second conveyor belt; The upper sealing device is fixedly connected to both sides of the packaging conveyor belt through a first mounting frame, a hot pressing roller is arranged at the lower side of the first mounting frame, a sealing positioning wheel is arranged at a side of the hot pressing roller close to the roll film, and a plasma processing unit is also connected to one side of the sealing positioning wheel; The cutting and sealing device comprises a second mounting frame, the second mounting frame is provided with a through hole, the through hole is sleeved in the middle of the second conveyor belt and the packaging conveyor belt, and the upper and lower parts of the through hole are connected to a guillotine through a push rod; The two sides of the guillotine are hot pressing blocks, the middle is a cutting knife, and the hot pressing block is provided with a heating plate inside; The method of using the device comprises the following steps: S1. First, pull out the roll film and pull it upward to the gap between the first conveyor belt and the packaging conveyor belt; then pull the roll film backward and pass both sides of the roll film through the roll film adjustment device, which bends the roll film inward to form a curved roll film; continue to pull the curved roll film backward to overlap both sides; pass the overlapping part through the sealing positioning wheel and then through the hot pressing roller, which heat-presses the overlapping part of the roll film to form a cylindrical shape with openings at both ends; S2. Turn on the gas supply device and plasma generator, adjust the output voltage between 20~30KV, the output frequency between 5~20KHz, turn on all conveyor belts at the same time, and control the production cycle at 20~30s; S3, placing the weighed packaged items to be sterilized into the cavity of the loading unit; S4. The packaged items to be sterilized pass through the first conveyor belt into the roll film filled with plasma gas. As the roll film continues to move backward, it passes through the cutting and sealing device and is sealed in the roll film under the action of the upper and lower guillotines to form a single independent sealed bag.

2. The plasma sterilization packaging device for agricultural products according to claim 1, characterized in that: The feeding unit comprises a feeding conveyor belt, on which a plurality of baffles are arranged at equal intervals, a cavity is formed between every two adjacent baffles, and the bottom of the feeding conveyor belt is fixed to the ground by supporting legs.

3. The plasma sterilization packaging device for agricultural products according to claim 2, characterized in that: The first conveyor belt is connected to the loading unit via a transition plate.

4. The plasma sterilization packaging device for agricultural products according to claim 3, characterized in that: The upper surfaces of the first conveyor belt, the packaging conveyor belt, and the second conveyor belt are located in the same horizontal plane, and the height of the horizontal plane where the first conveyor belt is located is lower than the height of the horizontal plane where the loading conveyor belt is located.

5. The plasma sterilization packaging device for agricultural products according to claim 4, characterized in that: The roll film is arranged on a reel, and two sides of the reel are fixedly connected to two sides of a packaging conveyor belt through connecting strips.

6. The plasma sterilization packaging device for agricultural products according to claim 5, characterized in that: The hot pressing roller and the sealing positioning wheel are at the same height, a heating plate is arranged inside the hot pressing roller, and rolling patterns are arranged on the surface of the hot pressing roller.

7. The plasma sterilization packaging device for agricultural products according to claim 6, characterized in that: The plasma processing unit includes a plasma generator, a power regulator and a gas supply device. The plasma generator is a coaxial dual-medium barrier reactor. The power regulator is a modulated pulse power supply with an output voltage of 0~30KV and an output frequency of 5~20KHz. The gas supply device is one of a gas cylinder or a gas generator. The gas provided by the gas supply device is one or more of air, nitrogen, oxygen, and argon.

8. The plasma sterilization packaging device for agricultural products according to claim 7, characterized in that: The upper interface of the plasma generator is a gas output interface, which is fixed in front of the sealing positioning wheel through an air guide tube. The lower interface of the plasma generator is a gas input interface, which is connected to the output port of the gas supply device through an air guide tube. The power regulator is electrically connected to the plasma generator.

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