A plasma treatment device and method suitable for surface sterilization of vegetables

Abstract

The application provides a plasma processing device and method suitable for sterilizing the surface of dried vegetables, wherein the high-voltage electrode is a plurality of strip-shaped metal strips, the distance between two adjacent strip-shaped metal strips is a certain distance, the plurality of strip-shaped metal strips are close to the inner wall surface of a quartz glass sleeve, the first grounding electrode is a cylinder coaxial with the quartz glass tube, the inside of the cylinder is hollow, one end of the cylinder is closed, the other end of the cylinder is connected with a gas pump, and a gas hole is arranged on the wall of the cylinder at a certain interval. The outer surface of the quartz glass tube is close to a circle of second grounding electrodes. The application provides a plasma processing device suitable for sterilizing the surface of dried vegetables, which uses high-energy electrons, active substances such as active oxygen and free radicals generated by low-temperature plasma to replace the traditional ultraviolet and ozone sterilization method, so as to realize the sterilization of dried vegetables. The whole device has a simple structure, thereby reducing the sterilization cost.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of plasma processing device, in particular to a kind of plasma processing device suitable for vegetable dry surface sterilization. BACKGROUND

[0002] With the increase of market demand, the yield of fruits and vegetables in China is increasing, and the varieties of fruits and vegetables are various. Fresh fruits and vegetables have high water content, and there is a demand for production area, which is easily affected by seasonality. Long-term storage at room temperature can easily lead to nutrient loss, rot and deterioration, especially for heat-sensitive vegetable products, making it very difficult to preserve fruits and vegetables. Therefore, fresh fruits and vegetables are processed into dried fruits and vegetables, which greatly prolongs the storage time of fruits and vegetables and does not cause nutrient loss. However, during the drying process, some bacteria may adhere to the surface of the dried vegetables, which can cause acute gastroenteritis if not properly cleaned before consumption, causing abdominal pain and serious harm to human health.

[0003] In the long-term sterilization process, people have invented various methods for sterilizing dried vegetables, which can be divided into physical and chemical methods. Including high-temperature steam sterilization, irradiation sterilization and ozone sterilization. Although the existing methods can reduce the residual bacteria to some extent, they also have problems such as incomplete sterilization, resource waste and affecting the taste of dried vegetables. The main reasons are as follows: 1. The surface of dried vegetables is not flat and has wrinkles, making it difficult to fully treat with existing sterilization methods; 2. The existing sterilization methods and means have long processing time, high cost, complicated processing process, are easily affected by experimental conditions, and are prone to reagent residue.

[0004] The patent with patent publication number CN111328870A uses a combination of ultraviolet light and titanium dioxide sterilization solution, which has a certain sterilization effect, but the food may be oxidized after being irradiated by ultraviolet light, which can affect the taste of the food. In addition, the penetration of ultraviolet light in solids is limited, and the sterilization effect is not ideal once it encounters stacked solids. In addition, the residue of the reagent is not easy to remove and may cause certain damage to the human body.

[0005] The patent with patent publication number CN212393740U uses ozone sterilization, which is irritating and harmful to the environment, and is generally not suitable for food processing.

[0006] The patent with patent publication number CN110870521A combines plasma and mechanical structure to achieve uniform treatment of food, but the overall device structure is complex and requires high energy to drive, which cannot achieve the purpose of energy saving. SUMMARY

[0007] 1. The technical problem to be solved:

[0008] In the extension of the shelf life of dried vegetables, how to carry out efficient sterilization, reduce cost, and not affect the taste of dried vegetables.

[0009] 2. Technical scheme:

[0010] In order to solve the above problems, the application provides a kind of plasma processing device suitable for the surface sterilization of dried vegetables, including dried vegetable sterilization device, the dried vegetable sterilization device 6 is connected with feed bin and storage bin respectively, the dried vegetable sterilization device 6 is plasma processing device, including high voltage electrode, first ground electrode, the high voltage electrode is connected with power supply, the high voltage electrode is a plurality of strip metal strips, the distance between adjacent two strip metal strips is a certain distance, each metal strip is connected by copper foil strip, the plurality of strip metal strips are closely attached to the inner wall surface of quartz glass sleeve, the first ground electrode is coaxial with quartz glass tube Cylindrical, the cylindrical interior is hollow, one end is closed, the other end is connected with air pump through air inlet hole, and gas hole is opened on the wall of the cylindrical every interval a certain distance.

[0011] Quartz glass tube outer surface closely attaches a circle of second ground electrode.

[0012] The second ground electrode is brass sheet.

[0013] The dried vegetable sterilization device is arranged on the lifting support, the lifting support includes base, two supports are arranged in parallel on the base, and each support is provided with concave circle, and the concave circle is in contact with the quartz glass tube.

[0014] One end of the first ground power supply is sealed by the upper sealing cover, the upper sealing cover has a wide notch for leading out the copper foil strip at the high voltage electrode and connecting with the power supply, and the upper sealing cover is connected with the quartz glass tube around.

[0015] The surface of the upper sealing cover has two fixed columns, and the surface is relatively rough. The belt is connected with the motor, and the motor drives the belt to drive the entire quartz glass sleeve, so that the dried vegetable sterilization device rotates forward and backward.

[0016] The material of the storage bin is polystyrene, the height is 80cm~100cm, the bottom is 30cm~50cm radius, a stainless steel mesh cover is arranged in the lower part of the storage bin, the bottom has air outlet hole, and the radius is 1~3cm.

[0017] The feed bin is provided with a stainless steel conveyor at the lower part, and the feed inlet of the dried vegetable sterilization device is provided with a lower sealing cover, the lower sealing cover is transparent and insulating material, and the lower sealing cover can be disassembled.

[0018] The metal strip is made of brass, with a thickness of 0.1-0.3mm, a width of 4-8mm, and one placed every 15-20mm; the first grounding electrode is made of stainless steel, with a length of 180-250mm, a radius of 8-16mm, and a hole opened every 15-20mm, with a hole diameter of 4-8mm; the quartz glass tube has a thickness of 0.5-1.5mm and a length of 200-300mm, and the copper foil strip has a length of 125-130mm.

[0019] The application also provides a use method of the plasma treatment device for sterilizing the surface of dried vegetables as described, comprising the following steps:

[0020] Step S01: control the feeding bin through the controller, and convey the untreated dried vegetables in the feeding bin to the dried vegetable sterilization device through the conveyor below; during the conveying process, the rear end of the lifting support is lifted to a certain angle to allow the untreated dried vegetables to slowly slide to the front end of the dried vegetable sterilization device.

[0021] Step S02: flatten the dried vegetables.

[0022] Step S03: turn on the power supply, ground the first grounding electrode and the second grounding electrode, connect the metal strip to high voltage, and adjust the parameters.

[0023] Step S04: control the air pump to introduce air with a certain flow rate into the dried vegetable sterilization device through the controller, and then the air flow introduced from the air holes on the first grounding electrode blows towards the dried vegetables, and the plasma is generated inside the quartz glass tube.

[0024] Step S05: then start the motor to rotate the dried vegetable sterilization device at a certain speed, and drive the dried vegetables in it to rotate.

[0025] Step S06: after the dried vegetables are sterilized, control the storage bin through the controller to suck the treated dried vegetables into it, and when the storage bin is full, empty the inside of the storage bin through the side bin door, so as to continue to convey the sterilized dried vegetables.

[0026] 3. Beneficial effects:

[0027] The application increases the discharge body space during processing in the vertical space, increases the quantity of vegetable dry processing, and also obtains more uniform processing effect; the holes are opened on the electrode, the vegetable dry is turned over by controlling the gas flow rate, and the active particles and long-life particles are diffused on the surface of the vegetable dry, so that the surface of the vegetable dry is sterilized in all directions without dead angle, and better effect is achieved; the application relates to a device and a method for sterilizing vegetable dry based on DBD plasma, and more active substances are generated in the processing bin through the arrangement mode of the electrode, the initial voltage of discharge is reduced, and better sterilization effect and lower energy consumption are obtained. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a system composition schematic diagram of the device.

[0029] Figure 2 is a structural section view of the vegetable dry sterilization device.

[0030] Figure 3 is a structural schematic diagram of the vegetable dry sterilization device.

[0031] Figure 4 is a specific sterilization flowchart of the vegetable dry.

[0032] Figure 5 is a lifting support structure schematic diagram.

[0033] Figure 6 is a first grounding electrode structure schematic diagram.

[0034] Figure 7 is a metal strip, copper foil strip and second grounding electrode schematic diagram.

[0035] Figure 8 is a partial structure exploded schematic diagram of the vegetable dry sterilization device.

[0036] BRIEF DESCRIPTION OF DRAWINGS: 1. Controller; 2. Gas pump; 3. Motor; 4. Storage bin; 5. Feeding bin; 6. Vegetable dry sterilization device, 7. Lifting support; 61. Upper sealing cover; 62. Metal strip; 63. First grounding electrode; 64. Quartz glass tube; 65. Copper foil strip; 66. Lower sealing cover; 67. Second grounding electrode; 68. Air inlet hole; 69. Air hole; 70. Air outlet hole; 71. Support; 72. Base; 8. Power supply. DETAILED DESCRIPTION

[0037] The application will be described in detail below in combination with the drawings and embodiments.

[0038] As Figure 1As shown, the plasma processing device for sterilizing the surface of dried vegetables of the present application comprises a controller 1, a gas pump 2, a motor 3, a storage bin 4, a feeding bin 5, a dried vegetable sterilization device 6 and a lifting support 7 at the bottom, wherein the dried vegetable sterilization device 6 is connected with the feeding bin 5 and the storage bin 4 respectively.

[0039] The dried vegetable sterilization device 6 is a plasma processing device, such as Figure 2 and Figure 3 As shown, it comprises a high-voltage electrode and a first grounding electrode, wherein the high-voltage electrode is connected with a power supply 8, the high-voltage electrode is a plurality of strip-shaped metal bars 62, the adjacent two strip-shaped metal bars 62 are spaced apart at a certain distance, each metal bar is connected through a copper foil strip 65, the plurality of strip-shaped metal bars 62 are tightly attached to the inner wall surface of a quartz glass sleeve 64, and the first grounding electrode 63 is a cylindrical shape coaxial with the quartz glass tube, such as Figure 6 As shown, the cylindrical shape is hollow, one end is closed, and the other end is connected with the gas pump 2 through a gas inlet hole 68, and the cylindrical wall is provided with gas holes 69 at every certain distance. The first grounding electrode 63 is provided with a hole, and the bottom of the quartz glass tube 64 is provided with an exhaust hole 70. By controlling the gas flow rate, the dried vegetables are turned over, and the active particles and long-life particles are diffused on the surface of the dried vegetables, so that the surface of the dried vegetables is sterilized in all directions without dead angle, and a better sterilization effect is achieved.

[0040] In one embodiment, the sealing cover 61 is a ring made of insulating material, with an outer radius of 20-40 mm and an inner radius of 8-16 mm, which is just matched with the first grounding electrode 63 to separate the outer space from the discharge space, and plays a sealing role,

[0041] In one embodiment, the metal bar 62 is made of brass, with a thickness of 0.1-0.3 mm and a width of 4-8 mm, and one is placed every 15-20 mm as a high-voltage electrode; the first grounding electrode 63 is a cylindrical shape with a length of 180-250 mm and a radius of 8-16 mm, which is used as a grounding electrode, and the inside is hollow for the convenience of gas inlet, and the electrode is provided with holes every 15-20 mm, with a hole diameter of 4-8 mm. The first grounding electrode 63 is provided with a hole, and by controlling the gas flow rate, the dried vegetables are turned over, and the active particles and long-life particles are diffused on the surface of the dried vegetables, so that the surface of the dried vegetables is sterilized in all directions without dead angle, and a better effect is achieved.

[0042] Through the electrode arrangement mode, the initial voltage of discharge is reduced, the volume-surface discharge mode is formed, the processing space is increased, more active substances are generated, better sterilization effect and uniformity are obtained, and the capacity of dried vegetable processing is also increased, and the energy consumption is reduced.

[0043] In one embodiment, the bottom of the first grounding electrode 63 is sealed, the main purpose is to ensure that the gas from the two holes out, the first grounding electrode 63 top connected with the air pump 2; metal strip 62 and the second grounding electrode 67 is a quartz glass tube 64, as shown in Figure 7 and Figure 8 The thickness is 0.5~1.5mm, the length is 200mm~300mm, the strip electrode 62 is close to the inner wall surface of the quartz glass sleeve 64; the upper and lower discharge space is symmetrical, the discharge spacing is 8~12mm, the processed vegetables are placed in the space between the first grounding electrode 63 and the outer glass sleeve 64. A circle of grounding electrode 67 is close to the outer surface of the quartz glass tube 64, the material is brass sheet, the length is 140~250mm, the thickness is 0.1mm.

[0044] Through the electrode arrangement, the initial voltage of the discharge is reduced, the bulk-surface hybrid discharge mode is formed, the processing space is increased, more active substances are produced, better sterilization effect and uniformity are obtained, and the capacity of the vegetable dry processing is increased, and the energy consumption is reduced.

[0045] In one embodiment, the storage bin 4 is made of polystyrene, the height is 80cm~100cm, and the bottom is a storage tank with a radius of 30cm~50cm to store the processed vegetable dry.

[0046] In one embodiment, the storage bin 4 has a stainless steel mesh cover inside, with a radius of 30cm~50cm, used for gas-solid separation, and a gas outlet hole with a radius of 1~3cm at the bottom, through which the internal gas flows into the external space.

[0047] In one embodiment, the feed bin 5 is integrated with the lower stainless steel conveyor, which pushes the untreated vegetable dry into the vegetable dry sterilization device 6, so as to perform sterilization operation.

[0048] In one embodiment, the vegetable dry sterilization device 6 is provided with a lower sealing cover 66 at the feeding port, and the lower sealing cover 66 is made of transparent insulating material. At the same time, the lower sealing cover 66 is detachable, which is convenient for adding the processed vegetable dry into the bin.

[0049] Throughout the sterilization process, surface discharge is generated between the metal strip 62, the second grounding electrode 67, and the quartz glass tube 64, while volume discharge is generated between the metal strip 62 and the first grounding electrode 63. This structural design reduces the starting voltage of the DBD plasma discharge and increases the discharge space during processing, thereby increasing the overall discharge intensity within the processing chamber and improving the processing capacity of the dried vegetables. With the assistance of airflow and mechanical rotation, a more uniform processing effect is also achieved. Simultaneously, more active substances are generated between the quartz glass tube 64 and the second grounding electrode 67, significantly improving the sterilization effect. By changing the flow rate of the introduced gas, the dried vegetables to be processed are turned over, achieving thorough sterilization without dead angles. Furthermore, the device has a simple overall structure, is easy to operate, and has low cost.

[0050] In one embodiment, the vegetable drying sterilization device 6 is mounted on a lifting support 7, which includes a base 72. Two supports 71 are arranged in parallel on the base 72. Each support 71 has a concave circle that is in contact with the quartz glass tube 64.

[0051] In one embodiment, one end of the first grounding electrode 63 is sealed by an upper sealing cover 61, the upper sealing cover 61 being connected to the quartz glass tube 64 around its perimeter.

[0052] The upper sealing cover 61 has two fixing posts on its surface, which is relatively rough. It is connected to the motor 3 via a belt, and the motor 3 drives the belt to drive the entire glass sleeve 64, thereby causing the vegetable drying sterilization device 6 to rotate forward and backward at a certain speed, causing the dried vegetables inside to rotate and be sterilized, thus achieving a more comprehensive and thorough sterilization effect.

[0053] The present invention also provides a method of using the plasma treatment device for surface sterilization of dried vegetables, as described above. Figure 4 As shown, controller 1 first controls the feeding hopper 5, which then conveys the untreated dried vegetables from the hopper to the vegetable sterilization device 6 via a conveyor at the bottom. At this point, the untreated dried vegetables will pile up at the rear of the sterilization device, preventing plasma from penetrating to the surface for effective sterilization, resulting in an unsatisfactory sterilization effect. The lifting support 7 can then be activated; its specific structure is shown below. Figure 5 As shown, it consists of a support 71 and a base 72. The front and rear ends are tilted at a certain angle, allowing the dried vegetables to slowly slide onto the plasma sterilization device 6 near the upper sealing cover 61. This allows the dried vegetables to be laid flat, enabling the plasma to effectively penetrate the surface of the vegetables, greatly improving the sterilization effect. Then it returns to a horizontal position for the next step of rotational sterilization.

[0054] The application provides a device for sterilizing vegetable dry based on DBD plasma, which uses high-energy electrons, active substances, such as active oxygen and free radicals, generated by low-temperature plasma to replace the traditional ultraviolet and ozone sterilization method, so as to realize sterilization of the vegetable dry. The whole device has simple structure, so that the sterilization cost is reduced.

Claims

1. A plasma processing device suitable for surface sterilization of dried vegetables, comprising a dried vegetable sterilization device (6) connected to a feed bin (5) and a storage bin (4) respectively, characterized in that: The vegetable dry sterilization device (6) is a plasma treatment device, comprising a high voltage electrode and a first grounding electrode, the high voltage electrode is connected with a power supply (8), the high voltage electrode is a plurality of strip-shaped metal strips (62), the adjacent two strip-shaped metal strips (62) are separated by a certain distance, each metal strip is connected through a copper foil strip (65), the plurality of strip-shaped metal strips (62) are closely attached to the inner wall surface of a quartz glass tube (64), the first grounding electrode (63) is a cylindrical shape coaxial with the quartz glass tube, the cylindrical shape is hollow, one end is closed, and the other end is connected with an air pump (2) through an air inlet hole (68), and a plurality of air holes (69) are formed on the wall of the cylindrical shape at every certain distance.

2. The plasma treatment device for dry surface sterilization of vegetables of claim 1, wherein: The outer surface of the quartz glass tube (64) is closely attached to a circle of second grounding electrodes (67).

3. The plasma treatment device for dry surface sterilization of vegetables of claim 2, wherein: The second grounding electrode (67) is a brass sheet.

4. The plasma treatment device for dry surface sterilization of vegetables of claim 1, wherein: The vegetable dry sterilization device (6) is arranged on a lifting support (7), the lifting support (7) comprises a base (72), two supports (71) are arranged in parallel on the base (72), and an inner recessed circle is arranged in each support (71), and the inner recessed circle is in contact with the quartz glass tube (64).

5. The apparatus for plasma treatment of the dry surface of vegetables according to any one of claims 1 to 4, characterized in that: One end of the first grounding electrode (63) is sealed by an upper sealing cover (61), the upper sealing cover (61) has a wide notch for leading out the copper foil strip (65) at the high voltage electrode and connecting with the power supply (8), and the upper sealing cover (61) is connected with the quartz glass tube (64) around.

6. The apparatus for plasma treatment of dry surfaces of vegetables as claimed in claim 5 wherein: The surface of the upper sealing cover (61) has two fixing columns, and the surface is relatively rough, which is connected with a motor (3) through a belt, and the motor (3) drives the belt to drive the entire quartz glass tube (64), so that the vegetable dry sterilization device (6) rotates forward and backward.

7. The apparatus for plasma treatment of the dry surface of vegetables according to any one of claims 1 to 4, characterized in that: The material of the storage bin (4) is polystyrene, the height is 80cm~100cm, the bottom is a radius of 30cm~50cm, a stainless steel mesh cover is arranged below in the storage bin (4), there is an air outlet hole at the bottom, and the radius is 1~3cm.

8. The apparatus for plasma treatment of the dry surface of vegetables according to any one of claims 1 to 4, characterized in that: The feeding bin (5) is provided with a stainless steel conveyor below, a lower sealing cover (66) is arranged at the inlet of the vegetable dry sterilization device (6), the lower sealing cover (66) is made of transparent insulating material, and the lower sealing cover (66) is detachable.

9. The apparatus for plasma treatment of the surface of vegetables for sterilization according to any one of claims 1 to 4, characterized in that: The metal strip (62) is made of brass, the thickness is 0.1-0.3mm, the width is 4~8mm, and one is placed every 15~20mm; the first grounding electrode (63) is made of stainless steel, the length is 180-250mm, the radius is 8-16mm, the holes are opened every 15-20mm, and the hole diameter is 4-8mm; the quartz glass tube (64) has a thickness of 0.5~1.5mm and a length of 200~300mm, and the copper foil strip (65) has a length of 125mm~130mm.

10. A method of using the plasma treatment device for surface sterilization of vegetable dry according to any one of claims 1-9, comprising the following steps: Step S01: through the control of the controller (1), the untreated vegetable dry in the feed bin (5) is transported to the vegetable dry sterilization device (6) through the conveyor below; in the process of transportation, the rear end of the lifting support (7) is lifted to a certain angle to let the untreated vegetable dry slowly slide to the front end of the vegetable dry sterilization device (6); Step S02: flatten the vegetable dry; Step S03: turn on the power supply (8), ground the first grounding electrode (63) and the second grounding electrode (67), connect the metal strip (62) to high voltage, and adjust the parameters; Step S04: through the controller (1), control the air pump (2) to input a certain flow rate of air into the vegetable dry sterilization device (6), then the input air flow blows to the vegetable dry from the air hole (69) on the first grounding electrode (63), and the plasma is generated inside the quartz glass tube (64); Step S05: then start the motor (3) to make the vegetable dry sterilization device (6) rotate at a certain speed to drive the vegetable dry in it to rotate; Step S06: after the sterilization of the vegetable dry is completed, through the controller (1), control the storage bin (4) to suck the treated vegetable dry into it, after the storage bin (4) is filled, empty the inside of the storage bin through the side bin door, so as to continue to transport the sterilized vegetable dry to it.

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