High-flux low-temperature plasma activated water generating device and preparation method thereof

Abstract

The invention discloses a large-flux low-temperature plasma activated water generating device and a preparation method thereof.The device comprises a set of large-flux low-temperature plasma jet combined generators, a frequency-adjustable high-voltage power source and a water tank, an adjustable guide water tank is arranged in the water tank, and the water flow speed of the guide water tank is adjustable; therefore, the acting time of the low-temperature plasma jet and water is regulated and controlled. An outlet of the jet flow combination generator is connected with a plasma airflow dividing and refining device which is inserted into water to form fine bubbles, so that the efficiency of fusion reaction with water flow is improved, and plasma activated water is formed in an accelerated mode. By combining a plurality of low-temperature plasma jet generators, the requirements of large-scale industrial production can be met. And secondly, the design of the guide water channel in the water tank effectively ensures that the water body is in full contact with the plasma, and the generation efficiency of the activated water is improved. The invention provides a special technical equipment foundation for large-scale production, cleaning and disinfection of agricultural and sideline products applied to the low-temperature plasma active water generator.

Description

Technical Field

[0001] The invention belongs to the technical field of low-temperature plasma cold sterilization, and in particular relates to a large-flux low-temperature plasma activated water generating device and a preparation method thereof. Background Art

[0002] Cold Plasma Sterilization (CPS) is the latest food cold sterilization technology in the world. It will not produce secondary pollution or chemical residues when sterilizing products, and is highly safe. The sterilization process is short, the temperature rise is low, and the energy consumption is low, which can adapt to the large-scale development of fresh prepared foods. Low-temperature plasma activated water (PAW) generator is a common method of low-temperature plasma cold sterilization, but currently it is an experimental device with a very small PAW generation volume. Invention patent publication number CN110913553B discloses a high-efficiency plasma activated water generation device, including a high-voltage power supply, a plasma generator, a water container, an air pump, a water pump, etc.; the plasma generator includes a ground electrode, a high-voltage electrode and a medium pipe, one end of the plasma generator is fixed to the bottom of the water container, and the water container is connected to a water pump outside, but the plasma activated water preparation device is suitable for treating a water volume of 1-2.5L, which cannot meet the needs of industrial production. Invention patent ZL202010462402.9: discloses a high-voltage electric field low-temperature plasma active water continuous generation device: PAW continuous generation is formed by connecting a group of low-temperature plasma jet unit generators in series, but the low-temperature plasma jet unit generator used is still experimental, with a very small processing capacity, and cannot meet the needs of large-scale production cleaning and disinfection.

[0003] In order to meet the needs of large-scale production, cleaning and disinfection of fresh agricultural and sideline products, it is imperative to develop a large-flux low-temperature plasma active water generator. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a large-flux plasma-activated water generating device and a preparation method thereof, so as to solve the shortcomings of existing equipment such as small water treatment volume, poor activation effect, and complex structure, and provide an efficient and sustainable technical solution for large-scale industrial production.

[0005] The technical solution provided by the present invention is as follows:

[0006] A high-flux low-temperature plasma activated water generating device comprises a group of high-flux low-temperature plasma jet combined generators, a frequency-adjustable high-voltage power supply, and a water tank with an adjustable guide water tank;

[0007] The adjustable frequency high voltage power supply matched with the large flux low temperature plasma jet combined generator has an operating frequency of 15-25kHz and an operating voltage of 6-12kV;

[0008] The internal high-voltage electrode end of the large-flux low-temperature plasma jet combined generator is more than 60 mm away from the water surface of the water tank, and the liquid level is controlled by a liquid level meter to prevent high-voltage breakdown and discharge.

[0009] Furthermore, the water flow velocity of the guide water tank can be adjusted to adjust the action time of the low-temperature plasma jet and the water.

[0010] Furthermore, a plasma airflow splitting and thinning device is connected to the outlet of the jet combination generator and inserted into the water to form fine bubbles, so as to improve the efficiency of the fusion reaction with the water flow and accelerate the formation of plasma activated water.

[0011] Furthermore, the guide water trough provided in the water tank is jointly configured with a group of large-flux low-temperature plasma jet combined generators to form a unidirectional water flow passing through each low-temperature plasma jet unit generator in turn.

[0012] Furthermore, pH and temperature sensors are arranged in the guide water tank to monitor the pH value and temperature value in real time, and the water inlet speed is controlled by a water flow valve controlled by a digital signal PLC feedback.

[0013] Furthermore, the action time of the low-temperature plasma jet and water is regulated to form low-temperature plasma activated water, wherein the pH value is controlled within the range of 2.5 to 3.5 and the temperature is controlled within the range of 45°C.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] First, by adopting multiple large-flux low-temperature plasma jet combined generators, the present invention can significantly increase the amount of plasma-activated water produced, meet the needs of large-scale industrial production, and is particularly suitable for large-scale processing scenarios such as fresh agricultural and sideline products. Secondly, the water tank and guide water tank design of the present invention ensure the full contact and efficient reaction between the water body and the plasma, avoiding the problems of uneven water flow and insufficient plasma action in the prior art, thereby improving the activation effect and processing efficiency of PAW. In addition, the modular design of the present invention enables the equipment to have high flexibility and scalability, and can be adjusted and optimized according to the production needs of different scales, avoiding the limitations of traditional equipment when the processing volume is insufficient or the processing effect is unstable. In general, the present invention has obvious innovation and practicality compared with the prior art in terms of improving processing capacity, optimizing equipment structure, improving activated water effect, and ensuring stability and sustainability, and can effectively promote the industrial application of low-temperature plasma cold sterilization technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of a large-flux plasma-activated water generating device provided by one embodiment of the present invention;

[0018] Figure 2 is a cross-sectional view of a high-flux plasma-activated water generating device provided by one embodiment of the present invention;

[0019] Figure 3 It is a top view of a water tank provided by one embodiment of the present invention.

[0020] The markings in the figure are: 1. Special connector for high-voltage electrode of unit generator; 2. High-voltage electrode; 3. Outer casing ground electrode; 4. Compressed air connecting device; 5. Compressed air inlet; 6. Metal support plate; 7. Special connector for high-voltage cable; 8. High-voltage cable interface; 9. Water tank; 10. Adjustable guide water tank; 11. Water tank cover; 12. Water inlet valve; 13. Drain valve; 14. Drain outlet; 15. Liquid level meter; 16. Water level. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of protection of the present invention.

[0022] Embodiment 1

[0023] like Figure 1 and Figure 2 As shown, this embodiment provides a large-flux plasma-activated water generating device, which mainly includes a group (two) of large-flux low-temperature plasma jet combined generators, an adjustable-frequency high-voltage power supply and a water tank.

[0024] The large flux low temperature plasma jet combined generator includes a plurality of low temperature plasma jet unit generators, each unit generator has an internal conical high voltage electrode 2 and a stepped conical outer shell ground electrode 3, which are connected by an insulating material between the two; at the same time, the outer shell ground electrode 3 is integrated through the metal support plate 6 of the combined generator and connected to the ground electrode of the frequency-adjustable high voltage power supply. The outer shell ground electrode 3 is evenly distributed on the metal support plate 6 of the combined generator, and the two are made of the same metal material and maintain a tight rigid connection. The internal high voltage electrode 2 is connected to the high voltage output end of the frequency-adjustable high voltage power supply through a special link 1 for the high voltage electrode of the unit generator. The metal material inside the special link has no sharp corners, and the outside is made of a high insulation material that can withstand a voltage of 25kV. A compressed air link device 4 is provided on the top of the combined generator, a compressed air inlet 5 is provided in the middle of the upper end surface, and the lower air outlet is connected to the air inlet of multiple unit generators, so as to facilitate the provision of necessary gas.

[0025] Furthermore, the conical high-voltage electrode 2 inside each low-temperature plasma jet unit generator is connected to the high-voltage output end of the adjustable-frequency high-voltage power supply through the high-voltage cable dedicated link 7 and the unit generator high-voltage electrode dedicated link 1 through the high-voltage cable interface 8. The discharge area of ​​the high-voltage electrode 2 is set as a ring cone surface. The design of the discharge surface area of ​​the ring cone surface optimizes the contact area between plasma and water and improves the activation efficiency. The operating frequency of the adjustable-frequency high-voltage power supply is 15 to 25 kHz, and the operating voltage is 6 to 12 kV.

[0026] like Figure 2 and Figure 3 As shown, the water tank 9 includes a water tank cover 11 and an adjustable guide water tank 10 bent in the water tank 9. An inlet valve 12 is provided at one end of the adjustable guide water tank 10, and a drain valve 13 and a drain port 14 are provided at the other end. The adjustable guide water tank 10 is used to guide the direction of the water flow, and the water flow speed is adjustable to control the action time of the low-temperature plasma jet and the water. A liquid level gauge 15 is also provided in the adjustable guide water tank 10 to monitor the water level 16 of the water tank to ensure that the high-voltage electrode 2 maintains a certain distance (greater than 60 mm) from the water surface to prevent breakdown. The water tank cover 11 is provided with a number of through holes to facilitate the insertion of the low-temperature plasma jet unit generator into the adjustable guide water tank 10 and prevent dust from entering the water tank 9.

[0027] When in use, first, the water enters the water tank 9 through the water inlet pipe and the water inlet valve 12, and the liquid level meter 15 monitors the water level in real time to ensure that it is within the appropriate range (keeping the water level at 130mm). Subsequently, the necessary gas (air) is provided through the compressed air inlet 5, and the plasma jet unit generator that is powered on works together to generate low-temperature plasma on the water surface or in the water. The active oxygen species in the plasma interact with the water molecules to activate the water and enhance its oxidation ability. The activated water flows in the water tank 9 and is discharged through the adjustable guide water tank 10 and the drain valve 13 to complete the entire activation process. The drain valve 13 is located above the drain port 14 to ensure that the activated water discharged from the drain valve 13 does not contain sediments such as impurities or dust, and the drain port 14 is used to discharge wastewater containing sediments in the device.

[0028] In some embodiments, the outlet of the high-flux low-temperature plasma jet combined generator is also provided with an airflow diversion and refinement device for inserting into water to form fine bubbles, thereby improving the fusion reaction efficiency with the water flow in the guide water tank and accelerating the formation of plasma-activated water.

[0029] In some embodiments, the adjustable guide water tank 10 is also provided with a pH sensor and a temperature sensor for real-time monitoring of the pH value and temperature value of the water body, and controlling the water inlet speed through a water flow valve controlled by a digital signal PLC feedback.

[0030] Embodiment 2

[0031] Based on the plasma-activated water generating device provided in the above embodiment, this embodiment provides a method for preparing plasma-activated water.

[0032] Experiment 1

[0033] The plasma activated water generating device was used to treat 40L of water. The voltage of the frequency-modulated high-voltage power supply was set to 8kV and the frequency was set to 20kHz. The 40L plasma activated water prepared under different treatment times was mixed with 10 8 The CFU / mL Escherichia coli suspension was mixed in a volume ratio of 1:1 and reacted at room temperature for 10 min. The bactericidal performance of plasma-activated water was evaluated by the plate count method.

[0034] Table 1 Bactericidal effect of plasma activated water on Escherichia coli at different preparation times

[0035]

[0036] The data in Table 1 show that after the water body was treated by the above-mentioned plasma activated water generating device for 30 minutes, the bactericidal effect was significant, and the colony count of Escherichia coli dropped from 8.25lg CFU / mL to 2.40lg CFU / mL.

[0037] Experiment 2

[0038] The plasma activated water generating device was used to set the frequency of the frequency modulated high voltage power supply to 20 kHz, and 40 L of water was treated at different voltages for 30 min. The 40 L of plasma activated water was mixed with 10 8 The CFU / mL Escherichia coli suspension was mixed in a volume ratio of 1:1 and reacted at room temperature for 10 min. The bactericidal performance of plasma-activated water was evaluated by the plate count method.

[0039] Table 2 Bactericidal effect of plasma activated water on Escherichia coli under different treatment voltages

[0040]

[0041] The data in Table 2 show that when the working voltage of the plasma activated water generator reaches 12 kV, its bactericidal effect is significant under the same preparation time, and the colony count of Escherichia coli is reduced from 8.25 lg CFU / mL to 1.53 lg CFU / mL.

[0042] Experiment 3

[0043] The plasma activated water generating device was used to set the voltage of the frequency modulated high voltage power supply to 8 kV, and 40 L of water was treated at different frequencies for 30 min. The 40 L of plasma activated water was mixed with 10 8 The CFU / mL Escherichia coli suspension was mixed in a volume ratio of 1:1 and reacted at room temperature for 10 min. The bactericidal performance of plasma-activated water was evaluated by the plate count method.

[0044] Table 3 Bactericidal effect of plasma activated water on Escherichia coli at different treatment frequencies

[0045]

[0046] The data in Table 3 show that when the operating voltage frequency of the plasma activated water generating device reaches 25kHz, under the same preparation time and treatment voltage, its bactericidal effect is significant, and the colony count of Escherichia coli is reduced from 8.25lg CFU / mL to 1.95lgCFU / mL.

[0047] Experiment 4

[0048] The plasma activated water generating device was used to treat 40 L of water at a voltage of 8 kV and a frequency of 20 kHz. A pH meter and a thermometer were used to measure the pH value and temperature of the plasma activated water at different preparation times.

[0049] Table 4 pH value and temperature of plasma activated water at different preparation times

[0050] Preparation time (min) 0 5 10 15 20 25 30 pH 5.75 3.10 2.97 2.86 2.78 2.70 2.65 temperature 20 31 34 38 40 42 44

[0051] The data in Table 4 show that as the preparation time increases, the pH value of plasma-activated water decreases rapidly until it stabilizes at around 2.65 at 30 minutes, which is consistent with the low pH value characteristics of plasma-activated water. At the same time, as the preparation time increases, the temperature of plasma-activated water gradually rises and stabilizes at 44°C after 30 minutes. These changes provide an important reference for the application of plasma-activated water in related fields.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-flux low-temperature plasma activated water generating device, comprising a group of high-flux low-temperature plasma jet combined generators, a frequency-adjustable high-voltage power supply, and a water tank with an adjustable guide water tank; characterized in that: The adjustable frequency high voltage power supply matched with the large flux low temperature plasma jet combined generator has an operating frequency of 15-25kHz and an operating voltage of 6-12kV; The internal high-voltage electrode end of the large-flux low-temperature plasma jet combined generator is more than 60 mm away from the water surface of the water tank, and the liquid level is controlled by a liquid level meter to prevent high-voltage breakdown and discharge.

2. A high-flux low-temperature plasma activated water generating device according to claim 1, characterized in that: The water flow speed of the guide water tank can be adjusted to adjust the action time of the low-temperature plasma jet and water.

3. A high-flux low-temperature plasma activated water generating device according to claim 1, characterized in that: A plasma airflow splitting and refinement device is connected to the outlet of the jet combination generator and inserted into the water to form fine bubbles to improve the efficiency of the fusion reaction with the water flow and accelerate the formation of plasma activated water.

4. A high-flux low-temperature plasma activated water generating device according to any one of claims 1 to 3, characterized in that: The guide water trough provided in the water tank is jointly configured with a group of large-flux low-temperature plasma jet combined generators to form a unidirectional water flow passing through each low-temperature plasma jet unit generator in turn.

5. A high-flux low-temperature plasma activated water generating device according to claim 1 or 2, characterized in that: pH and temperature sensors are set in the guide water tank to monitor the pH value and temperature value in real time, and the water inlet speed is controlled by the water flow valve controlled by the digital signal PLC feedback.

6. A high-flux low-temperature plasma activated water generating device according to claim 5, characterized in that: The action time of the low-temperature plasma jet and water is regulated to control the pH value of the low-temperature plasma activated water within the range of 2.5 to 3.5 and the temperature within the range of 45°C.

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