Plasma activated water preparation device, hydrogel preparation process and sterilization process

Abstract

The invention relates to a plasma-activated water preparation device, a hydrogel preparation process and a sterilization process. The working end of a first plasma generator in an activated water treatment chamber is located below the liquid surface of a solution to be treated, and plasma is generated below the liquid surface of the solution to be treated. The working end of a second plasma generator is located above the liquid surface of the solution to be treated, and plasma is generated by reacting with working gas that escapes from the first plasma generator and floats to the liquid surface of the treated solution, thereby improving the efficiency of plasma-activated water preparation. The plasma-activated water preparation device is used to prepare plasma-activated water from the solution to be treated that has been uniformly mixed with a gel, thereby improving the antibacterial and fresh-keeping effect of the ion-activated hydrogel. Fresh food is continuously transported and the plasma-activated water rich in active substances is sprayed on the fresh food, thereby improving the sterilization efficiency of the fresh food.

Description

Technical Field

[0001] The invention relates to the technical field of antibacterial and fresh-keeping, in particular to a plasma-activated water preparation device, a hydrogel preparation process and a sterilization process. Background Art

[0002] Food safety, as one of the most fundamental and important issues in human safety, has received widespread attention from people around the world. Among the many food categories, fresh food has become a necessity in people's daily lives. Although fresh food is produced in large quantities, it is prone to spoilage during transportation and storage due to physical damage, chemical changes, endogenous enzymes, and microbial effects, leading to food safety issues. This not only has serious impacts on people's health, but also causes certain losses to the national economy. Therefore, the development of efficient, automated, and continuous fresh food sterilization has important scientific and social significance.

[0003] According to existing research reports, the current methods for sterilizing fresh food include: heat sterilization, photodynamic sterilization, ozone sterilization, and ultraviolet sterilization. Among them, heat sterilization is the most widely used method at this stage, but prolonged heat treatment will cause a certain degree of damage to the flavor, color, and nutritional content of fresh food, and is not suitable for fruits and vegetables. Photodynamic sterilization has only achieved certain results in safety control, but its stability and effectiveness are still lacking, so it is subject to significant limitations. Ozone sterilization has been proven to be applicable to fresh food, but because it is toxic and has strong oxidizing properties, it can cause damage to food and the human body, so its use is strictly restricted. Ultraviolet sterilization technology can have a negative impact on the nutritional content and taste of fresh food, so it is also not suitable for fresh food.

[0004] The plasma-activated water sterilization method has been widely used in the field of fresh food sterilization because it has a large number of active substances that can effectively kill microorganisms on the surface of fresh food and degrade pesticide chemicals remaining on the surface. No chemical agents need to be added during the sterilization process, and no pollution is caused. However, it also faces certain problems. For example, the plasma-activated water equipment has a single form, and the preparation method mostly adopts the method of first preparing plasma and then relying on gas-liquid mass transfer to dissolve the plasma in the liquid to be treated. The efficiency of plasma-activated water preparation is not high; the method of using plasma-activated water to treat fresh food is mostly intermittent immersion sterilization, which is inefficient; the preparation of plasma-activated hydrogel materials usually involves adding gel materials after the plasma-activated water is prepared to prepare plasma-activated hydrogels, which cannot guarantee the effective ingredient content and uniformity of the active substances. When put into actual application and production, it will inevitably affect the antibacterial and fresh-keeping effects. Summary of the Invention

[0005] In response to the shortcomings of the above-mentioned existing production technologies, the applicant provides a plasma-activated water preparation device, a hydrogel preparation process and a sterilization process, thereby improving the efficiency of plasma-activated water preparation, the antibacterial and preservation effects of ion-activated hydrogels, and the efficiency of fresh food sterilization.

[0006] The technical solutions adopted in the present invention are as follows:

[0007] A plasma activated water preparation device comprises an activated water treatment chamber and a first plasma generator, wherein a water bath is provided outside the activated water treatment chamber, the activated water treatment chamber is used to hold a solution to be treated, and the water bath is used to control the working temperature of the solution to be treated in the activated water treatment chamber;

[0008] The working end of the first plasma generator is located below the liquid level of the solution to be treated, and the upper end of the first plasma generator is located outside the activated water treatment chamber and is connected to a first power supply and a gas supply device, wherein the first power supply is used to provide the voltage required for the first plasma generator to operate, and the gas supply device is used to provide working gas;

[0009] It also includes a second plasma generator, wherein a working end of the second plasma generator is located above the liquid surface of the solution to be treated, and the second plasma generator is connected to a second power supply;

[0010] The activated water treatment chamber is closed and has an air outlet above the liquid level of the solution to be treated, and the air outlet is located on one side of the second plasma generator;

[0011] The working end of the first plasma generator generates plasma below the liquid surface of the solution to be treated, and part of the working gas escapes from the first plasma generator and floats to the surface of the treatment solution. The working gas located above the liquid surface of the treatment solution reacts with the second plasma generator to generate plasma, and the remaining working gas is discharged from the gas outlet.

[0012] As a further improvement of the above technical solution:

[0013] The structure of the first plasma generator is as follows: it includes an insulating base and a high-voltage electrode mounted on the insulating base, the high-voltage electrode is a tubular structure, one end of the high-voltage electrode is connected to the gas supply device through a pipeline, and the other end of the high-voltage electrode is an exhaust end, the exhaust end is located below the liquid level of the solution to be treated after passing through the insulating base, a plurality of first electrode air holes are arranged in an array on the tube wall of the exhaust end, and the tube end of the exhaust end is sealed with an insulating plug, a ground electrode with a tubular structure is sheathed on the outside of the high-voltage electrode, the upper end of the ground electrode is connected to the insulating base, and a plurality of second electrode air holes are arranged in an array on the tube wall of the ground electrode at a position corresponding to the exhaust end, and the array directions of the first electrode air holes and the second electrode air holes are both radial and axial.

[0014] The high-voltage electrode and the ground electrode are concentrically arranged, and the diameter of the air hole of the first electrode is smaller than the diameter of the air hole of the second electrode;

[0015] The high-voltage electrode is connected to the first power supply, and the grounding electrode is grounded. An electric field is formed between the outer wall of the high-voltage electrode and the inner wall of the grounding electrode, which ionizes the working gas escaping from the pores of the first electrode, and the unionized working gas escapes from the pores of the second electrode.

[0016] The diameter of the pores of the first electrode is at the μm level; the diameter of the pores of the second electrode is at the mm or cm level.

[0017] The distance between the outer wall of the high-voltage electrode and the inner wall of the ground electrode is 2 to 4 mm.

[0018] The second plasma generator includes a plurality of single electrodes arranged in a horizontal array, the single electrodes are connected to the second power supply, and the activated water treatment chamber is made of metal and is grounded.

[0019] It also includes a concentration detection device, the detection end of which is arranged in the activated water treatment chamber and is used to detect the content of active substances in the plasma-activated water.

[0020] A hydrogel preparation process, using the plasma activated water preparation device, comprises the following steps:

[0021] Step 1: dissolving the temperature-sensitive gel in the solution to be treated and then adding the solution into the activated water treatment chamber;

[0022] Step 2: Controlling the temperature of the water bath to ensure that the liquid temperature in the activated water treatment chamber is at the operating temperature, the first plasma generator operates to generate plasma below the liquid surface and dissolve the plasma in the solution to be treated, and the second plasma generator generates plasma above the liquid surface and dissolves the plasma in the solution to be treated to form an ion-activated hydrogel aqueous solution;

[0023] Step 3: After the active substances in the plasma-activated hydrogel meet the standards, the first plasma generator and the second plasma generator stop working, and then the plasma-activated hydrogel aqueous solution in the activated water treatment chamber is transformed into a solid-phase hydrogel.

[0024] As a further improvement of the above technical solution:

[0025] The temperature-sensitive gel is one or more of polyethylene glycol-polypropylene ether copolymer, methyl fiber, and polylactic acid-polyethylene glycol-polylactic acid mixture.

[0026] A sterilization process for sterilizing fresh food, comprising a sterilization chamber and a material conveying mechanism, wherein the material conveying mechanism extends from an inlet to an outlet within the sterilization chamber, and a spray mechanism is provided within the sterilization chamber. The spray mechanism is connected to the activated water chamber of the plasma activated water preparation device via a spray pipeline, and a spray pump is provided on the spray pipeline.

[0027] The sterilization process includes the following steps:

[0028] Step 1: preparing plasma activated water in the activated water treatment chamber;

[0029] Step 2: The material conveying mechanism continuously transports the fresh food to be sterilized to the sterilization treatment chamber, and the spray pump transports the plasma activated water from the spray pipeline to the spray mechanism, and the spray mechanism evenly sprays the plasma activated water on the surface of the fresh food for sterilization.

[0030] As a further improvement of the above technical solution:

[0031] The system also includes a cooling water generator and a waste liquid pool for collecting waste water generated by sterilization. The water bath is connected to the water outlet of the cooling water generator through a first pipeline. A first valve is provided on the first pipeline. The water inlet of the cooling water generator is connected to a sewage purification device through a second pipeline. The sewage purification device is used to purify waste water from the waste liquid pool. A circulation pump and a second valve are sequentially provided on the second pipeline. A second pipeline between the circulation pump and the second valve is connected to the bottom of the activated water treatment chamber through a third pipeline. A third valve is provided on the third pipeline. The second valve is located between the third pipeline and the sewage purification device.

[0032] In steps 1 and 2, the liquid temperature in the activated water treatment chamber is 0°C to 8°C. The temperature control method of the activated water treatment chamber is as follows: when it is detected that the cooling water temperature of the water bath is higher than the set temperature, the first valve and the third valve are kept open, and the circulating pump is turned on to circulate the cooling water in the water bath through the cooling water generator for cooling before entering the water bath;

[0033] In steps 1 and 2, when the liquid level in the water bath is insufficient, the first valve is opened, the second valve is opened, and the third valve is closed, and the circulating pump sends the water in the sewage purification device into the water bath after heat exchange in the cooling water generator.

[0034] The beneficial effects of the present invention are as follows:

[0035] The invention has a compact and reasonable structure and is easy to operate. By arranging two plasma generators, plasma is generated below the liquid surface, and working gas that is not ionized by the first plasma generator reacts with the second plasma generator above the liquid surface, thereby improving the efficiency of plasma-activated water preparation in a dual-electrode coupling manner.

[0036] Plasma-activated hydrogels are directly prepared using a plasma-activated water preparation device. The plasma-activated water preparation process involves uniformly mixing the solution to be treated with the gel. This allows the active substances to automatically disperse between the gel molecules and the water molecules, ensuring a uniform distribution of the active substances throughout the hydrogel during the phase transition. This effectively prevents the loss of active substances, improves the activity of the plasma-activated hydrogel, and ensures the uniformity of the active substances within the hydrogel. The hydrogels produced by this method can be used as antibacterial materials for fresh foods, enhancing their sterilization and preservation during production, transportation, storage, and sales.

[0037] By continuously conveying fresh food and spraying it with plasma-activated water rich in active substances, the fresh food can be sterilized continuously and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a pipeline flow diagram of the present invention.

[0039] Figure 2 Schematic diagram of the structure of the first plasma generator of the present invention.

[0040] Figure 3 for Figure 2 sectional view of .

[0041] Figure 4 It is a three-dimensional diagram of the first plasma generator of the present invention.

[0042] Figure 5 Schematic diagram of the structure of the second plasma generator of the present invention.

[0043] Figure 6 Schematic diagram of the structure of the second plasma generator of the present invention (from another perspective).

[0044] Figure 7 Schematic diagram of the relevant structure of the sterilization treatment chamber of the present invention.

[0045] Wherein: 1. Activated water treatment chamber; 10. Air outlet; 11. Concentration detection device; 12. First liquid level sensor;

[0046] 2. First plasma generator; 20. First power supply; 21. Insulating base; 22. High-voltage electrode; 220. First electrode air hole; 23. Ground electrode; 230. Second electrode air hole;

[0047] 3. Water bath; 31. Second liquid level sensor; 32. Temperature sensor; 4. Liquid storage tank; 41. Liquid inlet pipeline; 411. Liquid inlet pump; 410. Liquid inlet valve; 5. Air supply device;

[0048] 6. Second plasma generator; 60. Second power supply; 61. Single electrode; 62. Electrode disk; 63. Mounting portion;

[0049] 7. Sterilization treatment chamber; 71. Spray mechanism; 72. Conical bottom; 73. Material conveying mechanism;

[0050] 74. Spray pipeline; 740. Drain valve; 741. Spray pump;

[0051] 8. Waste liquid pool; 81. Sewage purification device;

[0052] 9. Cooling water generator; 91. First pipeline; 910. First valve; 92. Second pipeline; 920. Second valve; 921. Circulation pump; 93. Third pipeline; 930. Third valve; 100. Control system. DETAILED DESCRIPTION

[0053] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0054] Example 1:

[0055] like Figures 1-6 As shown, the plasma activated water preparation device of this embodiment includes an activated water treatment chamber 1 and a first plasma generator 2. A water bath 3 is provided outside the activated water treatment chamber 1. The activated water treatment chamber 1 is used to hold the solution to be treated, and the water bath 3 is used to control the working temperature of the solution to be treated in the activated water treatment chamber 1.

[0056] The working end of the first plasma generator 2 is located below the liquid level of the solution to be treated, and the upper end of the first plasma generator 2 is located outside the activated water treatment chamber 1 and is connected to the first power supply 20 and the gas supply device 5. The first power supply 20 is used to provide the voltage required for the first plasma generator 2 to work, and the gas supply device 5 is used to provide working gas;

[0057] The system further comprises a second plasma generator 6, wherein a working end of the second plasma generator 6 is located above the liquid surface of the solution to be treated, and the second plasma generator 6 is connected to a second power supply 60;

[0058] The activated water treatment chamber 1 is closed and has an air outlet 10 above the liquid level of the solution to be treated. The air outlet 10 is located on one side of the second plasma generator 6.

[0059] The working end of the first plasma generator 2 generates plasma below the liquid surface of the solution to be treated, and part of the working gas escapes from the first plasma generator 2 and floats to the surface of the treatment solution. The working gas located above the liquid surface of the treatment solution reacts with the second plasma generator 6 to generate plasma, and the remaining working gas is discharged from the outlet 10.

[0060] Specifically, the solution to be treated can be tap water, deionized water, ultrapure water, etc., but for the plasma-activated water preparation device of this embodiment, deionized water is recommended as the best, and 0-8 mM NaCl needs to be added to the solution before preparing plasma-activated water. This helps to accelerate the rate of pH reduction, increase in oxidation-reduction potential (OPR), and increase in conductivity during the preparation process, as well as improve the energy efficiency of RONS preparation.

[0061] The first power supply 20 and the second power supply 60 are both high-voltage power supplies, which can be part of the device or an external power supply. The gas supply device 5 usually adopts an air pump to provide working gas to the first plasma generator 2 through an insulated pipe. The working gas can be one or more of argon, nitrogen, and compressed air.

[0062] The water bath 3 is arranged outside the activated water treatment chamber 1 to form a heat exchange jacket structure, which receives cold from the external heat exchange device and adopts a cooling water bath method to regulate the working temperature of the solution to be treated in the activated water treatment chamber 1 during the preparation process; preferably, the working temperature can be controlled below 4°C, which extends the decay period of short-lived active substances, not only improving the efficiency of plasma activated water preparation but also ensuring the content of active substances in the activated water.

[0063] The first plasma generator 2 produces plasma below the liquid surface and directly dissolves the plasma in the water. Compared with the method of first preparing the plasma and then relying on gas-liquid mass transfer to dissolve the plasma in the liquid to be treated, the loss of active substances during gas-liquid two-phase transfer is greatly reduced; the working gas that is not ionized by the first plasma generator 2 floats up and gathers above the liquid surface to form a positive pressure. The closed activated water treatment chamber 1 is provided with an outlet 10 above the liquid surface on one side of the second plasma generator 6, so that the working gas is discharged from the outlet 10 under the action of the pressure difference. The flowing working gas fully contacts the second plasma generator 6 to generate plasma, thereby ensuring the utilization rate of the working gas.

[0064] By setting up two plasma generators, plasma is generated below the liquid surface, while the working gas that is not ionized by the first plasma generator 2 reacts with the second plasma generator 6 above the liquid surface, thereby improving the efficiency of plasma-activated water preparation in a dual-electrode coupling manner.

[0065] Further, if Figure 2-Figure 4 As shown, the structure of the first plasma generator 2 is as follows: it includes an insulating base 21 and a high-voltage electrode 22 mounted on the insulating base 21, the high-voltage electrode 22 is a tubular structure, one end of the high-voltage electrode 22 is connected to the gas supply device 5 through a pipeline, and the other end of the high-voltage electrode 22 is an exhaust end, which is located below the liquid level of the solution to be treated after passing through the insulating base 21, and a plurality of first electrode pores 220 are provided in an array on the tube wall of the exhaust end, and the tube end of the exhaust end is sealed with an insulating plug 24, and a grounding electrode 23 with a tubular structure is provided on the outside of the high-voltage electrode 22, and the upper end of the grounding electrode 23 is connected to the insulating base 21, and a plurality of second electrode pores 230 are provided in an array on the tube wall of the grounding electrode 23 at a position corresponding to the exhaust end, and the array directions of the first electrode pores 220 and the second electrode pores 230 are both radial and axial directions;

[0066] The high voltage electrode 22 and the ground electrode 23 are concentrically arranged, and the diameter of the first electrode pore 220 is smaller than the diameter of the second electrode pore 230;

[0067] The high-voltage electrode 22 is connected to the first power supply 20, and the grounding electrode 23 is grounded. An electric field is formed between the outer wall of the high-voltage electrode 22 and the inner wall of the grounding electrode 23, which ionizes the working gas escaping from the first electrode pores 220, and the unionized working gas escapes from the second electrode pores 230.

[0068] Specifically, the high-voltage electrode 22 and the ground electrode 23 are both tubular structures with two ends through, and are made of metal that is not easily corroded by water. The end of the high-voltage electrode 22 located below the liquid surface is sealed with an insulating plug 24 made of insulating material, so that the working gas can pass completely through the first electrode pore 220, thereby improving the utilization rate of the working gas in the first plasma generator 2; when fixing the high-voltage electrode 22, the insulating base 21 can be detachably connected to the top of the activated water treatment chamber 1; Figure 2-Figure 4 As shown, the ends of the insulating base 21 and the grounding electrode 23 are connected by flange type, a through hole is opened in the middle of the insulating base 21, and the high-voltage electrode 22 is inserted into the through hole of the insulating base 21 by interference fit; the gas supply device 5 is connected to the high-voltage electrode 22 by an insulating hose; the anode of the first power supply 20 is connected to the high-voltage electrode 22, and the cathode is connected to the grounding electrode 23.

[0069] The ground electrode 23 tube wall array at the position corresponding to the exhaust end is provided with multiple second electrode pores 230, which means that the first electrode pores 220 and the second electrode pores 230 are flush at the beginning and end sections; the diameter of the second electrode pores 230 is larger than the diameter of the first electrode pores 220, so that the unionized tiny bubbles can be gathered into large bubbles and then escape.

[0070] The high-voltage electrode 22 serves as both an electrode and an output end for the working gas. The annular electric field between the outer wall of the high-voltage electrode 22 and the inner wall of the grounding electrode 23 ionizes the working gas, generating plasma which then dissolves in the annular electric field. The second electrode pores 230 not only allow the unionized working gas to escape in a timely manner, but also maintain a certain ion concentration in the annular electric field, thereby reducing the resistance of water and improving energy efficiency.

[0071] The annular opening at the bottom end of the annular electric field and the second electrode pores 230 serve as mass transfer channels, enabling the active material and untreated working gas to be transferred to the outside of the first plasma generator 2 .

[0072] The high-voltage electrode 22 and the ground electrode 23 are concentrically arranged to uniformly distribute the potential with a simple structure. The array directions of the first electrode air holes 220 and the second electrode air holes 230 are radial and axial, making full use of the characteristics of the tubular structure, so that the area where the first plasma generator 2 generates plasma is sufficiently large, increasing the effective area of ​​the electrode, improving the generation efficiency of the plasma, and making full use of the power supply energy.

[0073] A high-voltage electrode 22 with a tubular structure is placed on the surface of the ground electrode 23 to form a circular electric field. A first electrode pore 220 is provided on the high-voltage electrode 22 to release the working gas into the electric field to generate plasma. The second electrode pore 230 guides the unionized working gas out of the first plasma generator 2, thereby generating plasma below the liquid surface of the solution to be treated, directly dissolving the plasma in water, and improving the efficiency of preparing plasma-activated water.

[0074] Furthermore, the diameter of the first electrode pores 220 is at the μm level; the diameter of the second electrode pores 230 is at the mm or cm level.

[0075] The first electrode pores 220 are at the μm level to improve the ionization efficiency of the working gas; preferably, the diameter of the first electrode pores 220 is 100-300 μm, and the diameter of the second electrode pores 230 is 3-4 mm.

[0076] Furthermore, the distance between the outer wall of the high voltage electrode 22 and the inner wall of the ground electrode 23 is 2 to 4 mm.

[0077] The distance between the outer wall of the high-voltage electrode 22 and the inner wall of the ground electrode 23 is set to 2 to 4 mm, so that the distance between the positive and negative electrodes of the electric field is small, so that the active substances in the annular electric field quickly rise to a higher concentration level, thereby improving energy efficiency.

[0078] Further, if Figure 5-Figure 6 As shown, the second plasma generator 6 includes a plurality of single electrodes 61 arranged in a horizontal array. The single electrodes 61 are connected to a second power supply 60. The activated water treatment chamber 1 is made of metal and is grounded.

[0079] The second plasma generator 6 adopts an array electrode structure, which expands the interaction position between the second plasma generator 6 and the working gas and improves the processing capacity of the second plasma generator 6.

[0080] Specifically, the single electrode 61 is a metal needle-shaped electrode or a metal burr-like structure. The second plasma generator 6 includes an electrode disk 62 for mounting the single electrode 61. The electrode disk 62 is provided with a mounting portion 63. The mounting portion 63 is used to securely mount the second plasma generator 6 and to lead out a power connection line. The array electrode portion of the second plasma generator 6 is a high-voltage electrode, which can be a metal electrode with numerous burrs or a manually installed metal needle array electrode. The single electrodes 61 of the second plasma generator 6 are all above the liquid surface, without an additional metal grounding electrode, and are directly grounded through the activated water treatment chamber 1.

[0081] Furthermore, it also includes a concentration detection device 11, the detection end of the concentration detection device 11 is set in the activated water treatment chamber 1, and is used to detect the content of active substances in the plasma-activated water.

[0082] When preparing plasma activated water, the content of its active substances is not detected in real time, and the content of active substances cannot be accurately monitored. The concentration detection device 11 detects the content of active substances in the process of preparing plasma activated water in real time, including The concentration detection device 11 is a purchased part, and can be a series of sensor groups, such as an instrument for measuring conductivity, an instrument for measuring pH and redox potential, and a fluorescent probe for RONS detection.

[0083] In addition to the above-mentioned concentration detection device 11, the automatic control component of the plasma-activated water preparation device also includes a first liquid level sensor 12 located in the activated water treatment chamber 1. The first liquid level sensor 12 is used to detect whether the liquid level is above the working end of the first plasma generator 2 and below the working end of the second plasma generator 6; it also includes a second liquid level sensor 31 and a temperature sensor 32 located in the water bath 3. A liquid storage tank 4 is provided on one side of the activated water treatment chamber 1. The liquid storage tank 4 is used to store the solution to be treated and is connected to the activated water treatment chamber 1 through an inlet pipe 41. The inlet pipe 41 is provided with an inlet valve 410 and an inlet pump 411. The inlet pump 411 is used to deliver the solution to be treated stored in the liquid storage tank 4 into the activated water treatment chamber 1; a drain valve 740 is provided at the bottom drain port of the activated water treatment chamber 1 for discharging plasma-activated water; the above-mentioned valves are all solenoid valves.

[0084] The first liquid level sensor 12, the second liquid level sensor 31, the concentration detection device 11, the temperature sensor 32 are connected to the control system 100 of the preparation device. The control system 100 is arranged in the control cabinet of the preparation device. The air supply device 5, the liquid inlet pump 411, the liquid inlet valve 410, the first power supply 20, the second power supply 60 and the drain valve 740 are also connected to the control system 100. In addition, the liquid supply system and the heat exchange device connected to the water bath 3 are also connected to the control system 100. By detecting the liquid level, active substance and temperature, the liquid inlet, liquid discharge, temperature control and the start and shut down of the electrode during the operation of the plasma-activated water preparation device are automatically controlled, thereby realizing automatic operation of the preparation device.

[0085] like Figure 1 As shown, during the automatic operation of the plasma activated water preparation device of this embodiment:

[0086] First, the liquid inlet valve 410 is opened, the liquid inlet pump 411 is started, and the solution to be treated in the liquid storage tank 4 is pumped into the activated water treatment chamber 1. When the first liquid level sensor 12 detects that the liquid level of the solution to be treated reaches the maximum water level line, the liquid inlet valve 410 and the liquid inlet pump 411 are closed;

[0087] While or after the treatment solution is injected into the activated water treatment chamber 1, the liquid supply system of the water bath 3 injects cooling water into the water bath 3, and the heat exchange device cools the cooling water. Preferably, the temperature of the cooling water is controlled at about 4°C. When the second liquid level sensor 31 detects that the liquid level of the cooling water is higher than the liquid level of the solution to be treated, the injection of cooling water is stopped.

[0088] When the temperature and liquid level of the water bath 3 reach the set values, the gas supply device 5 and the first power supply 20 and the second power supply 60 are turned on, and the working gas is sent into the first plasma generator 2 from the insulating pipe. The first electrode pore 220 at the working end of the first plasma generator 2 generates μm-level bubbles, which are broken down in the annular electric field of the first plasma generator 2 to generate plasma. The plasma directly dissolves in the treatment solution to generate H + 、 and Other active substances.

[0089] When the first plasma generator 2 is working, some μm-level bubbles are not ionized. After escaping from the second electrode pores 230, the bubbles merge with each other and float on the surface and finally burst, causing the working gas to accumulate above the liquid surface in the activated water treatment chamber 1. Under the action of the pressure difference between the inside and outside of the activated water treatment chamber 1, it flows toward the outlet 10. The working gas above the liquid surface is ionized by the second plasma generator 6 to produce active substances such as O3, NO, and NO2, which are then dissolved in the solution to be treated, generating H + 、 and Active substances such as the working gas are fully utilized and make up for the lack of the first plasma generator 2 in the underwater discharge. content.

[0090] The concentration detection device 11 detects the content of various active substances in the plasma-activated water in the activated water treatment chamber 1 in real time, and when the content reaches a desired value, the preparation of plasma-activated water can be stopped.

[0091] The working gas can be compressed air, argon or other gases, but for the plasma activated water preparation device of this embodiment, compressed air is the best. When compressed air is used, the content of various active substances will not be reduced.

[0092] Different combinations of gases can be used to complement each other for different fresh foods and different sterilization requirements. For example, if a large amount of H2O2 is required, argon is used as the main working gas and nitrogen as the secondary working gas to make up for the lack of active nitrogen substances.

[0093] The plasma-activated water preparation device of this embodiment couples a first plasma generator 2 for generating plasma below the liquid with a second plasma generator 6 for generating plasma above the liquid, thereby achieving efficient preparation of plasma-activated water.

[0094] The uniquely designed structure of the first plasma generator 2 allows tiny bubbles to be ionized in a limited space and a relatively closed electric field, reducing the energy consumption of the first plasma generator 2. Plasma is generated by breaking down tiny bubbles, and the plasma can be directly dissolved in the treatment liquid, greatly reducing the loss of active substances during gas-liquid two-phase transfer. Moreover, after a period of use, the electrons generated by ionization are accumulated in the electric field, which greatly reduces the ionization time and the required ionization energy, thereby improving the energy efficiency of the electrode in generating active substances such as RONS (reactive oxygen and nitrogen clusters).

[0095] For the array electrode, the second plasma generator 6 makes up for the lack of ionization of the first plasma generator 2. Some unionized tiny bubbles will connect with each other to form large bubbles, and float above the liquid to be treated and eventually break, so that the gas enters the liquid, thereby forming a pressure difference with the external gas, so that the gas is discharged outward. The array electrode will be installed at the gas outlet (gas outlet 10), and these gases to be discharged will be ionized to generate plasma and then dissolved in the liquid. In this way, the working gas is fully utilized and the active substances generated in small amounts by the first plasma generator 2 during underwater discharge are compensated.

[0096] Example 2:

[0097] Plasma-activated water only exists in liquid form and its active ingredients are not easy to preserve, making it inconvenient to use for antibacterial preservation during the transportation, storage, and sales of fresh food. Plasma-activated water can be prepared into antibacterial hydrogels, which can be used as antibacterial materials for fresh food, improving the freshness of fresh food during preparation, transportation, storage, and sales, ultimately realizing the efficient preparation and multi-form use of plasma-activated water.

[0098] Conventional plasma-activated hydrogel preparation methods involve first preparing plasma-activated water, then adding gel material, and then preparing the plasma-activated hydrogel through a series of methods such as stirring and shaking. This method cannot guarantee the uniformity of the distribution of active substances. When put into practical production, it is inevitable that some gels will have extremely low active substance content, failing to achieve the antibacterial and fresh-keeping effects. Furthermore, in conventional preparation methods, plasma-activated water is first prepared, then removed, and then gel material is added to prepare the plasma-activated hydrogel. During this process, the active substances may be lost due to the influence of a series of external factors such as temperature, oxygen exposure, and time.

[0099] Temperature fluctuations can affect the active substances in the plasma-activated water. During the gelling process, temperature changes can cause degradation or alteration of the active substances. Exposure to oxygen can lead to oxidation reactions, resulting in loss of active substances. After the plasma-activated water is treated, prolonged exposure to the environment can cause irreversible changes in the active substances.

[0100] This embodiment adopts a method of directly preparing plasma-activated water in a mixed solution of water and gel, which can avoid the above-mentioned problems.

[0101] The hydrogel preparation process of this embodiment, using the plasma-activated water preparation device of Example 1, includes the following steps:

[0102] Step 1: dissolving the temperature-sensitive gel in the solution to be treated and then adding it into the activated water treatment chamber 1;

[0103] Step 2: Control the temperature of the water bath 3 to ensure that the liquid temperature in the activated water treatment chamber 1 is at the operating temperature. The first plasma generator 2 operates to generate plasma below the liquid surface and dissolve it in the solution to be treated. The second plasma generator 6 generates plasma above the liquid surface and dissolves it in the solution to be treated to form an ion-activated hydrogel aqueous solution.

[0104] Step 3: After the active substances in the plasma-activated hydrogel meet the standards, the first plasma generator 2 and the second plasma generator 6 stop working, and then the plasma-activated hydrogel aqueous solution in the activated water treatment chamber 1 is transformed into a solid-phase hydrogel.

[0105] In the first step: the solution to be treated can be tap water, deionized water, ultrapure water, etc., preferably deionized water with 0-8mM NaCl added; usually the mass ratio of the temperature-sensitive gel to the solution to be treated is 1:3-1:5. The temperature-sensitive gel can be dissolved in the solution to be treated in the liquid storage tank 4 and added to the activated water treatment chamber 1 through the liquid inlet pump 411 and the liquid inlet pipeline 41.

[0106] Step 2: While generating plasma-activated water, the temperature of the liquid in the activated water treatment chamber 1 is controlled in the range of 0°C to 8°C, preferably 0°C to 4°C, by using the water bath 3 to maintain the miscibility of the plasma-activated water with the gel, so that the plasma is immediately dispersed in the water molecules between the gel molecules after being generated.

[0107] In step 3, the preparation can be stopped after the concentration detection device 11 detects that the active substances in the plasma activated hydrogel aqueous solution meet the standard. Wait until the temperature of the activated water treatment chamber 1 rises to room temperature of about 25°C, and the gel aqueous solution spontaneously changes into a solid phase.

[0108] After step 3, if the hydrogel needs to be used, the upper cover of the activated water treatment chamber 1 is opened, the prepared gel is taken out, and covered on the surface of fresh food to inhibit bacteria and preserve freshness during transportation and storage.

[0109] Furthermore, the temperature-sensitive gel is one or more of polyethylene glycol-polypropylene ether copolymer, methyl cellulose, and polylactic acid-polyethylene glycol-polylactic acid mixture.

[0110] This embodiment uses a plasma-activated water preparation device to directly prepare plasma-activated hydrogels. The plasma-activated water preparation process involves uniformly mixing the treated solution with the gel. This allows the active substances to automatically disperse between the gel molecules and the water molecules, ensuring a uniform distribution of the active substances throughout the hydrogel during the phase transition. This effectively prevents the loss of active substances, improves the activity of the plasma-activated hydrogel, and ensures the uniformity of the active substances within the hydrogel. The hydrogels produced by this method can be used as antibacterial materials for fresh foods, enhancing the sterilization and preservation of fresh foods during production, transportation, storage, and sales.

[0111] Example 3:

[0112] like Figure 1 、 Figure 7 As shown, the sterilization process of this embodiment is used for sterilizing fresh food, including a sterilization chamber 7 and a material conveying mechanism 73. The material conveying mechanism 73 extends from the inlet to the outlet inside the sterilization chamber 7. A spray mechanism 71 is provided in the sterilization chamber 7. The spray mechanism 71 is connected to the activated water treatment chamber 1 of the plasma activated water preparation device of Example 1 through a spray pipeline 74. A spray pump 741 is provided on the spray pipeline 74.

[0113] The sterilization process includes the following steps:

[0114] Step 1: preparing plasma activated water in the activated water treatment chamber 1;

[0115] Step 2: The material conveying mechanism 73 continuously conveys the fresh food to be sterilized to the sterilization treatment chamber 7, and the spray pump 741 conveys the plasma-activated water from the spray pipe 74 to the spray mechanism 71. The spray mechanism 71 evenly sprays the plasma-activated water on the surface of the fresh food for sterilization.

[0116] Specifically, the material conveying mechanism 73 can be a conventional roller conveyor line or a mesh chain conveyor line, and the spraying mechanism 71 is a power-driven rotating spray pipe with multiple nozzles installed on the spray pipe. The spraying mechanism 71 is preferably arranged at the upper part of the sterilization treatment chamber 7, and the spraying mechanism 71 can also be arranged at the upper and lower parts, as long as the spraying mechanism 71 can evenly spray the plasma-activated water on the surface of the fresh food; the lower part of the sterilization treatment chamber 7 is a conical bottom 72 formed by multiple inclined plates, which is used to collect the liquid sprayed by the spraying mechanism 71.

[0117] Fresh food can be meat, fruits and vegetables, etc. Taking fruits as an example, when an apple is placed on the roller conveyor line, it rolls forward under the action of the roller conveyor line and is sprayed with plasma-activated water through the upper spray mechanism 71 to achieve uniform washing.

[0118] By continuously conveying fresh food and spraying it with plasma-activated water rich in active substances, the fresh food can be sterilized continuously and efficiently.

[0119] Furthermore, it includes a cooling water generator 9 and a waste liquid pool 8 for collecting waste water generated by sterilization. The water bath 3 is connected to the water outlet of the cooling water generator 9 through a first pipeline 91. A first valve 910 is provided on the first pipeline 91. The water inlet of the cooling water generator 9 is connected to a sewage purification device 81 through a second pipeline 92. The sewage purification device 81 is used to purify the waste water from the waste liquid pool 8. A circulating pump 921 and a second valve 920 are provided on the second pipeline 92 in sequence. The second pipeline 92 between the circulating pump 921 and the second valve 920 is connected to the bottom of the activated water treatment chamber 1 through a third pipeline 93. A third valve 930 is provided on the third pipeline 93. The second valve 920 is located between the third pipeline 93 and the sewage purification device 81.

[0120] In steps 1 and 2, the temperature of the liquid in the activated water treatment chamber 1 is 0°C to 8°C. The temperature control method of the activated water treatment chamber 1 is as follows: when it is detected that the temperature of the cooling water in the water bath 3 is higher than the set temperature, the first valve 910 and the third valve 930 are kept open, and the circulation pump 921 is turned on to circulate the cooling water in the water bath 3 through the cooling water generator 9 to cool it down and then enter the water bath 3;

[0121] In steps 1 and 2, when the liquid level in the water bath 3 is insufficient, the first valve 910 is opened, the second valve 920 is opened, and the third valve 930 is closed. The circulating pump 921 sends the water in the sewage purification device 81 into the water bath 3 after heat exchange through the cooling water generator 9.

[0122] Specifically, the above valves are all solenoid valves, and the control system 100 is connected to the cooling water generator 9, the first valve 910, the second valve 920, the third valve 930, and the circulating pump 921; the cooling water generator 9 is the liquid supply system and heat exchange device of the water bath 3, and the cooling water generator 9 can be a chiller with a built-in water tank and a circulating water pump. When the water bath 3 is filled with water for the first time, the water in the built-in water tank of the cooling water generator 9 can be connected to the built-in circulating water pump through the first pipeline 91 to send the water in the built-in water tank of the cooling water generator 9 into the water bath 3. At this time, the built-in water tank is supplied with water by its external pipeline.

[0123] When the plasma activated water preparation device is working and sterilization is being carried out in the sterilization treatment chamber 7, the liquid temperature in the activated water treatment chamber 1 is 0℃~8℃, preferably 0℃~4℃ to maintain the activity of the active substance; the temperature of the water bath 3 is preferably controlled at 0℃~4℃. Since the temperature inside the activated water treatment chamber 1 rises slowly, the temperature of the water bath box can be controlled at 0℃~4℃ to control the temperature of the activated water treatment chamber 1 to 0℃~4℃.

[0124] When the set temperature of the cooling water in the water bath 3 is set to 4°C, the temperature sensor 32 in the water bath 3 detects that the temperature of the cooling water is higher than 4°C. The temperature sensor 32 feeds back a signal to the control system 100. The control system 100 opens the first valve 910 and the third valve 930, starts the circulation pump 921 and turns on the cooling water generator 9 to cool the cooling water.

[0125] When the second liquid level sensor 31 detects that the liquid level of the cooling water is lower than the liquid level of the solution to be treated, the control system 100 opens the first valve 910 and the second valve 920, closes the third valve 930, and the circulating pump 921 sends the water in the sewage purification device 81 into the water bath 3 after heat exchange through the cooling water generator 9. In this process, the flow rate of the circulating pump 921 matches the flow rate of the built-in circulating water pump of the cooling water generator 9. When the liquid level of the cooling water is higher than the liquid level of the solution to be treated, the first valve 910, the second valve 920, the third valve 930 and the circulating pump 921 are stopped and closed.

[0126] The waste liquid in the waste liquid pool 8 enters the sewage purification device 81 for purification, and the cooling water generator 9 is connected to the water bath 3 and the sewage purification device 81 through a pipeline system, which not only realizes the water replenishment and temperature control of the water bath 3, but also realizes the full utilization of water resources.

[0127] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any modifications may be made within the scope of protection of the present invention.

Claims

1. A plasma activated water preparation device, characterized in that: The invention comprises an activated water treatment chamber (1) and a first plasma generator (2), wherein a water bath (3) is provided outside the activated water treatment chamber (1), the activated water treatment chamber (1) is used to hold a solution to be treated, and the water bath (3) is used to control the operating temperature of the solution to be treated in the activated water treatment chamber (1); The working end of the first plasma generator (2) is located below the liquid level of the solution to be treated, and the upper end of the first plasma generator (2) is located outside the activated water treatment chamber (1) and is connected to a first power supply (20) and a gas supply device (5), wherein the first power supply (20) is used to provide the voltage required for the first plasma generator (2) to operate, and the gas supply device (5) is used to provide working gas; It also includes a second plasma generator (6), wherein a working end of the second plasma generator (6) is located above the liquid surface of the solution to be treated, and the second plasma generator (6) is connected to a second power supply (60); The activated water treatment chamber (1) is closed, and an air outlet (10) is provided above the liquid level of the solution to be treated, and the air outlet (10) is located on one side of the second plasma generator (6); The working end of the first plasma generator (2) generates plasma below the liquid surface of the solution to be treated, and part of the working gas escapes from the first plasma generator (2) and floats to the surface of the treatment solution. The working gas above the liquid surface of the treatment solution reacts with the second plasma generator (6) to generate plasma, and the remaining working gas is discharged from the gas outlet (10); The structure of the first plasma generator (2) is as follows: it includes an insulating base (21) and a high-voltage electrode (22) mounted on the insulating base (21), the high-voltage electrode (22) is a tubular structure, one end of the high-voltage electrode (22) is connected to the gas supply device (5) through a pipeline, the other end of the high-voltage electrode (22) is an exhaust end, the exhaust end is located below the liquid level of the solution to be treated after passing through the insulating base (21), a plurality of first electrode pores (220) are arranged in an array on the tube wall of the exhaust end, the tube end of the exhaust end is blocked by an insulating plug (24), a grounding electrode (23) with a tubular structure is sheathed on the outside of the high-voltage electrode (22), the upper end of the grounding electrode (23) is connected to the insulating base (21), and a plurality of second electrode pores (230) are arranged in an array on the tube wall of the grounding electrode (23) at a position corresponding to the exhaust end, and the array directions of the first electrode pores (220) and the second electrode pores (230) are both radial and axial. The high-voltage electrode (22) and the grounding electrode (23) are concentrically arranged, and the diameter of the first electrode air hole (220) is smaller than the diameter of the second electrode air hole (230); The high-voltage electrode (22) is connected to the first power source (20), and the grounding electrode (23) is grounded. An electric field is formed between the outer wall of the high-voltage electrode (22) and the inner wall of the grounding electrode (23), ionizing the working gas escaping from the first electrode pores (220), and the unionized working gas escapes from the second electrode pores (230).

2. The plasma-activated water preparation device according to claim 1, wherein: The distance between the outer wall of the high-voltage electrode (22) and the inner wall of the ground electrode (23) is 2-4 mm.

3. The plasma-activated water preparation device according to claim 1, wherein: The second plasma generator (6) comprises a plurality of single electrodes (61) arranged in a horizontal array, the single electrodes (61) being connected to the second power supply (60), and the activated water treatment chamber (1) is made of metal and is grounded.

4. The plasma-activated water preparation device according to claim 1, wherein: It also includes a concentration detection device (11), wherein the detection end of the concentration detection device (11) is arranged in the activated water treatment chamber (1) and is used to detect the content of active substances in the plasma-activated water.

5. A process for preparing a hydrogel, characterized in that: The plasma activated water preparation device according to claim 1 comprises the following steps: Step 1: dissolving the temperature-sensitive gel in the solution to be treated and then adding the solution into the activated water treatment chamber (1); Step 2: The temperature of the water bath (3) is controlled to ensure that the temperature of the liquid in the activated water treatment chamber (1) is at the working temperature, the first plasma generator (2) operates to generate plasma below the liquid surface and dissolve the plasma in the solution to be treated, and the second plasma generator (6) generates plasma above the liquid surface and dissolves the plasma in the solution to be treated to form an ion-activated hydrogel aqueous solution; Step 3: After the active substances in the plasma-activated hydrogel meet the standards, the first plasma generator (2) and the second plasma generator (6) stop working, and then the plasma-activated hydrogel aqueous solution in the activated water treatment chamber (1) is phase-transformed into a solid-phase hydrogel.

6. The process for preparing the hydrogel according to claim 5, wherein: The temperature-sensitive gel is one or more of polyethylene glycol-polypropylene ether copolymer, methyl fiber, and polylactic acid-polyethylene glycol-polylactic acid mixture.

7. A sterilization process, characterized in that: Used for sterilizing fresh food, comprising a sterilization treatment chamber (7) and a material conveying mechanism (73), wherein the material conveying mechanism (73) extends from an inlet to an outlet inside the sterilization treatment chamber (7), and a spraying mechanism (71) is provided inside the sterilization treatment chamber (7), wherein the spraying mechanism (71) is connected to the activated water treatment chamber (1) of the plasma activated water preparation device according to claim 1 through a spraying pipeline (74), and a spraying pump (741) is provided on the spraying pipeline (74); The sterilization process includes the following steps: Step 1: preparing plasma activated water in the activated water treatment chamber (1); Step 2: The material conveying mechanism (73) continuously conveys the fresh food to be sterilized to the sterilization treatment chamber (7), and the spray pump (741) conveys the plasma-activated water from the spray pipeline (74) to the spray mechanism (71), and the spray mechanism (71) evenly sprays the plasma-activated water on the surface of the fresh food to sterilize it; It also includes a cooling water generator (9) and a waste liquid pool (8) for collecting waste water generated by sterilization. The water bath (3) is connected to the water outlet of the cooling water generator (9) through a first pipeline (91). A first valve (910) is provided on the first pipeline (91). The water inlet of the cooling water generator (9) is connected to a sewage purification device (81) through a second pipeline (92). The sewage purification device (81) is used to purify waste water from the waste liquid pool (8). A circulation pump (921) and a second valve (920) are provided on the second pipeline (92) in sequence. The second pipeline (92) between the circulation pump (921) and the second valve (920) is connected to the bottom of the activated water treatment chamber (1) through a third pipeline (93). A third valve (930) is provided on the third pipeline (93). The second valve (920) is located between the third pipeline (93) and the sewage purification device (81). In step 1 and step 2, the temperature of the liquid in the activated water treatment chamber (1) is 0°C to 8°C. The temperature control method of the activated water treatment chamber (1) is as follows: when it is detected that the temperature of the cooling water in the water bath (3) is higher than the set temperature, the first valve (910) and the third valve (930) are kept open, and the circulating pump (921) is turned on to circulate the cooling water in the water bath (3) through the cooling water generator (9) to cool the cooling water and then enter the water bath (3); In steps 1 and 2, when the liquid level in the water bath (3) is insufficient, the first valve (910) is opened, the second valve (920) is opened, and the third valve (930) is closed, and the circulating pump (921) sends the water in the sewage purification device (81) into the water bath (3) after heat exchange through the cooling water generator (9).

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