A method and apparatus for dual mode on-line plasma electrospray

Abstract

The application discloses a kind of dual-mode online preparation plasma electric spray method and device, and plasma activation water technical field;It includes opening plasma power supply, air pump and water pump, water flow is contacted with central electrode and is electrified, is sprayed into lower electric field by water outlet, forms spray under the action of electric field force and airflow;Part of gas is ionized in first ionization region to form active oxygen substance dominant plasma.Another part of gas enters sliding arc plasma source, ionizes to form nitrogen oxide dominant plasma.After two parts of plasma are sprayed by gas outlet, further ionization after entering second ionization region, a large number of short-lived active particles are generated, to further improve the retention rate of short-lived active ingredients, to ensure the diversity of active ingredients in the generated plasma, and react with spray to form plasma activated water mist.Activated water mist can be sprayed onto the surface of an object for sterilization and disinfection.

Description

Technical Field

[0001] This invention relates to the field of plasma-activated water technology, specifically to a method and apparatus for dual-mode online preparation of plasma electrospray. Background Technology

[0002] Plasma-activated water sterilization is a branch of plasma sterilization technology, belonging to an indirect sterilization method. Plasma-activated water is produced by contacting an aqueous solution with plasma-active substances generated by electrical discharge, resulting in a series of chemical effects in a gas-liquid environment. The activated water contains a large number of active substances, such as hydroxyl groups, superoxide compounds, nitrates, nitrites, and hydrogen peroxide. Some of these substances have a strong killing effect on microorganisms. Its advantages include high sterilization efficiency, no toxic or harmful byproducts generated during preparation, environmental friendliness, and a relatively long antibacterial time.

[0003] There are many structures that can generate plasma-activated water. Different discharge structures have different discharge energies and product characteristics, thus producing activated water with their own unique features. Common structures include: sliding arc structures, jet structures, dielectric barrier discharge structures, bare electrode discharge structures, and electro-jet spark discharge structures. Based on the interaction mechanism between low-temperature plasma and water, plasma-activated water preparation methods can be broadly classified into three categories: gas phase discharge on the liquid surface, direct liquid phase discharge, and discharge in multiphase environments, such as discharge in bubbles within a liquid or contact liquid spray and foam discharge.

[0004] However, several problems remain when applying plasma-activated water to real-world applications. First, plasma-activated water requires a certain reaction time between the plasma and water, typically 5-10 minutes depending on the volume, making online generation and immediate use impossible. Second, the effective time of plasma-activated water is short; it cannot be stored for long periods after generation, and some effective active substances become inactive within 15 minutes, significantly reducing its bactericidal effect. The types of active particles in plasma generated by a single discharge mode are relatively limited. For example, plasma generated by a dielectric barrier discharge structure is mainly composed of reactive oxygen species, which has good loading capacity but low particle activity. Plasma generated by a sliding arc discharge structure is mainly composed of reactive nitrogen species; while this type of plasma has high particle activity, its loading capacity is poor, further limiting the inactivation effect of the activated water. Finally, the time it takes for activated water to deposit and adsorb on the target surface after being sprayed is short, further limiting its bactericidal effect.

[0005] Existing technologies disclose methods and apparatuses for online preparation of plasma-activated water, such as: ① Chinese Invention Patent Application No.: 202311404343.X, title: Integrated needle high-voltage mixed discharge low-temperature plasma atomization device; ② Chinese Invention Patent Application No.: 2023113359365, title: A method and apparatus for preparing plasma-activated water; ③ Chinese Invention Patent Application No.: 2023106754482, title: A plasma jet activated water spray device and method; ④ Chinese Invention Patent Application No.: 202111129595.7, title: An atmospheric pressure atomized plasma high-efficiency sterilization device and method.

[0006] The above devices all utilize the reaction between plasma and water to generate plasma-activated water and water mist, but they have the following problems: (1) Plasma-activated water has a preparation time, and it is impossible to generate and use plasma-activated water immediately; (2) Using the traditional atomization method, the droplets are difficult to adsorb onto the surface of the object being disinfected, which affects the disinfection effect; (3) Using a single discharge mode, the active substances in the generated plasma are not rich enough, and the short-lived active substances die quickly, making it difficult to guarantee the diversity of active ingredients in the generated water mist. Summary of the Invention

[0007] The purpose of this invention is to provide a method and apparatus for dual-mode online preparation of plasma electrospray, which further enhances the variety of active components in the plasma by setting dual discharge modes and multiple ionization regions; and the activated water disinfection has good stability, high reliability, and the droplets are easily adsorbed onto the surface of the object to be disinfected.

[0008] To achieve the above objectives, the technical solution of this application is: a method for dual-mode online preparation of plasma electrospray, comprising:

[0009] The liquid flows through the water inlet channel of the plasma-activated water mist generator into the first water storage tank, and then through the water delivery channel into the second water storage tank. In the first and second water storage tanks, the liquid comes into contact with the energized central high-voltage electrode, causing the liquid to become charged. Then, it flows out from the outlet at the bottom of the second water storage tank into the second ionization region. The charged liquid is torn apart into droplets under the action of the electric field force.

[0010] A portion of the gas enters the plasma-activated water mist generator through the gas delivery channel, where it undergoes preliminary ionization in the first discharge region to form active particles. Among these, long-lived active particles are retained after ionization, generating a large amount of plasma dominated by active oxygen substances. Another portion of the gas enters the sliding arc plasma source, where it discharges to generate a large amount of plasma dominated by nitrogen oxides. Both portions of the plasma enter the second ionization region, assisting in droplet atomization while the plasma is ionized to form a large number of short-lived active particles, which react with the droplets to generate plasma-activated water mist.

[0011] In one embodiment, the working gas for generating plasma is air.

[0012] In one embodiment, the liquid used to generate the plasma-activated water mist is pure water, deionized water, or other suitable liquid water.

[0013] This application also provides a dual-mode online plasma electrospray preparation apparatus, comprising:

[0014] Plasma power supply, used for power supply;

[0015] A plasma-activated water mist generator includes a first water storage chamber, a second water storage chamber, and a central high-voltage electrode connected to a plasma power source, all located within a housing. The inlet of the first water storage chamber is connected to a water inlet channel, and the outlet is connected to the second water storage chamber via a water delivery channel. The upper part of the central high-voltage electrode is located within the first water storage chamber, and the lower part is located within the second water storage chamber. The bottom of the second water storage chamber has an outlet. A first ionization region is formed between the middle of the central high-voltage electrode and a first grounding electrode on the outer wall of the housing, and a second ionization region is formed between the bottom of the central high-voltage electrode and a second grounding electrode on the outer wall of the housing. The first and second ionization regions form a gas storage cavity. The housing has an air inlet, and an air outlet is formed between the bottom of the second water storage chamber and the housing.

[0016] The air intake channel has its inlet connected to the air source and its outlet connected to the air inlet of the plasma-activated water mist generator.

[0017] The sliding arc plasma source has its inlet connected to the air intake channel, and its outlet connected to the second ionization region of the plasma-activated water mist generator through the air supply channel.

[0018] In one embodiment, the bottom of the second water storage tank is provided with an inner boss and an outer boss, with a water outlet formed between the inner boss and the central high-voltage electrode, and an air outlet formed between the outer boss and the inner platform of the shell.

[0019] In one embodiment, the first ionization region and the second ionization region are dielectric barrier discharge structures.

[0020] In one embodiment, the first grounding electrode and the second grounding electrode are copper metal rings.

[0021] In one embodiment, the central high-voltage electrode is fixed inside the housing by an upper base and a lower bracket.

[0022] In one embodiment, the top cover, the first ionization region, and the second ionization region of the shell are made of polytetrafluoroethylene, while the other parts are made of stainless steel; the first water storage tank and the second water storage tank are made of insulating ceramic.

[0023] In one embodiment, a water pump and a check valve are provided in the water inlet channel; and an air pump and a check valve are provided in the air inlet channel.

[0024] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0025] This invention integrates electrospray and gas discharge technologies, successfully shortening the preparation time of plasma-activated water and achieving online, instantaneous generation of activated water in the form of water mist. This breakthrough enables plasma-activated water technology to be flexibly applied to scenarios such as medical nebulization therapy, intelligent nebulization disinfection doors, and household sensor-activated nebulizer nozzles, meeting the urgent need for rapid preparation and immediate use of activated water.

[0026] This invention adopts a split water storage tank structure, which cleverly leaves the middle of the central high-voltage electrode empty, and together with the external grounding electrode, it constructs the first ionization region, which effectively promotes the generation of long-lived active oxygen substances, thereby increasing the concentration and activity of active particles in the subsequent second ionization region.

[0027] To address the issue of short-lived active particles being easily lost during the transmission of air plasma within the device, this invention incorporates a second ionization region, which significantly increases the concentration of active particles in the plasma that reaches and reacts with the water mist, thereby enhancing the inactivation efficiency of plasma-activated water against harmful microorganisms.

[0028] Furthermore, this invention introduces a dual discharge mode of dielectric barrier discharge and sliding arc discharge. The dielectric barrier discharge mode focuses on generating highly reactive oxygen species, while the sliding arc discharge focuses on generating highly reactive nitrogen species. The synergistic effect of these two discharge modes not only further enhances the sterilization effect of plasma-activated water mist, but the generation of reactive nitrogen species can also significantly reduce the potential damage of H2O2 to human tissues during sterilization, making the activated water mist prepared by this device show broad application prospects in the field of human wound disinfection and sterilization. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1This is a schematic diagram of a dual-mode online plasma electrospray preparation method.

[0031] Figure 2 A schematic diagram of the apparatus for dual-mode online plasma electrospray preparation;

[0032] Figure 3 A structural diagram of the water flow / gas flow outlet of the apparatus for dual-mode online plasma electrospray preparation.

[0033] The numbers in the diagram are as follows: 1. Plasma power supply; 2. Upper base; 3. Water pump; 4. Water inlet channel; 5. Air pump; 6. Air inlet channel; 7. Central high-voltage electrode; 8. First water storage chamber; 9. Outer shell (stainless steel); 10. Gas storage chamber; 11. Second water storage chamber; 12. Gas outlet; 13. Water outlet; 14. First grounding electrode; 15. Outer shell (PTFE); 16. First ionization region; 17. Second ionization region; 18. Sliding arc plasma source; 19. Lower support; 20. Second grounding electrode; 21. Gas delivery channel. Detailed Implementation

[0034] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0035] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0037] In the description of this application, it should be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a method for dual-mode online preparation of plasma electrospray, including:

[0041] When water pump 3 is turned on, deionized water is sent into the first water storage tank 8 through the inlet channel 4 via the one-way valve, and then into the second water storage tank 11 through the delivery channel. In the first and second water storage tanks, the deionized water comes into contact with the energized central high-voltage electrode 7, which makes it energized. Since the central high-voltage electrode is energized, the released electrical energy can initially electrolyze the deionized water to generate a certain concentration of H2O2, which helps to increase the concentration of active ingredients in the plasma-activated water mist generated later. The deionized water is discharged from the outlet 13 into the second ionization region below, where it is torn into fine droplets under the action of the electric field.

[0042] Then turn on the air pump 5, and the working gas is air. A portion of the gas flows through the one-way valve and the air inlet channel 6 into the first ionization region 16 in the middle of the plasma-activated water mist generator. In the electric field, the air is ionized to form plasma dominated by active oxygen substances, including H2O2 and ONOOH. - ONOO -The plasma, including O3, flows through the gas storage cavity 10 and exits through the gas outlet 12 into the second ionization region. This plasma also acts on the water flow, further reducing the atomization particle size of the droplets. Another portion of the gas enters the sliding arc plasma source 21, where it discharges to generate a large amount of plasma primarily composed of nitrogen oxides, including HNO2, N2O3, and N2O4. Short-lived active particles may be lost during transport. This plasma enters the second ionization region through the gas delivery channel 21. It should be noted that the active particles in these two plasmas participate in the reaction in the second ionization region 17, generating a large amount of short-lived active substances such as OH-. - O2 - NO + NO - This compensates for the potential loss of active materials during transportation and further increases the concentration of active particles in the plasma;

[0043] In the second ionization region, the atomized droplets react immediately with the active particles in the two plasma regions mentioned above, generating plasma-activated water mist. No preparation time is required, allowing for the instant generation and use of plasma-activated water. The generated plasma-activated water mist is sprayed onto the surface of the object to be disinfected, treating harmful microorganisms.

[0044] Example 2

[0045] like Figure 2-3 As shown, a dual-mode online plasma electrospray preparation device is used to perform the method described in Embodiment 1 above, including a plasma power supply 1, a plasma-activated water mist generator, and a sliding arc plasma source;

[0046] The plasma-activated water mist generator includes a first water storage chamber 8, a second water storage chamber 11, a gas storage chamber 10, and a central high-voltage electrode connected to the plasma power supply 1, all located within the housing. The central high-voltage electrode is made of copper and is fixed at two points: an upper base 2 and a lower support 19, to prevent displacement of the central high-voltage electrode when the water flow is large. The first water storage chamber 8 and the second water storage chamber 11 are made of insulating ceramic to prevent short circuits between the central high-voltage electrode and the chamber walls after water flow. The outer shell of the gas storage chamber is made of stainless steel, while the top cover, the first ionization region, and the second ionization region are all made of insulating polytetrafluoroethylene. The water storage chamber adopts a split design, connected by two water supply channels. This design leaves space in the middle of the central high-voltage electrode, forming a first ionization region between it and the external first grounding electrode. This region is used for preliminary ionization of the gas, increasing the concentration of active ingredients in the final plasma-activated water mist.

[0047] Preferably, the air pump is turned on first, followed by the water pump, to prevent the initial spray from lacking active particles. The airflow and water flow rates are adjusted according to the needs of the scenario.

[0048] In this embodiment, gas is introduced by a gas pump and discharged from the outlet. Part of the gas flow enters the first discharge region for preliminary ionization, forming a plasma dominated by a large amount of active oxygen. The other part of the gas enters the sliding arc plasma source, where discharge generates a large amount of plasma dominated by nitrogen oxides. Long-lived active particles are retained after ionization, which can increase the concentration of active particles generated in the next ionization. Then, the gas flow and water flow enter the second ionization region together. On the one hand, the gas flow can assist the atomization of the liquid; on the other hand, after entering the electric field, it is ionized, and a large amount of active nitrogen and active oxygen react in this region, replenishing the short-lived active substances lost in the previous discharge region. This allows the plasma to react with the droplets, generating plasma-activated water mist.

[0049] In this embodiment, the plasma-activated water mist generator, the first water storage tank, and the second water storage tank are cylindrical.

[0050] In this embodiment, the sliding arc plasma source includes a sliding arc discharge structure and a polytetrafluoroethylene shell, and is driven by an external AC plasma power supply.

[0051] This invention combines electrospray technology with dielectric barrier discharge technology, sliding arc discharge technology, and ambient temperature and pressure plasma jet technology, solving the problems of plasma-activated water not being able to be generated online, the limited variety of active components in activated water, and the difficulty of droplets adsorbing onto target surfaces. By designing a dual-mode discharge and multiple ionization regions, this invention further enhances the concentration of long-lived and short-lived active components in the plasma. Compared to designs with a single discharge mode and ionization region, this further enriches the variety of active components during the plasma-water mist reaction. Since the variety of active components in the plasma is related to their concentration, increasing the concentration of short-lived active components significantly improves the diversity of active components, including reactive oxygen and nitrogen substances, in both the plasma and activated water. This solves the problem of difficulty in ensuring the diversity of active components in the generated water mist due to the decay of short-lived active substances in the generated plasma.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for dual-mode online preparation of plasma electrospray, characterized in that, This method is implemented based on a dual-mode online plasma electrospray preparation device, which includes: Plasma power supply, used for power generation; A plasma-activated water mist generator includes a first water storage chamber, a second water storage chamber, and a central high-voltage electrode connected to a plasma power source, all located within a housing. The inlet of the first water storage chamber is connected to a water inlet channel, and the outlet is connected to the second water storage chamber via a water delivery channel. The upper part of the central high-voltage electrode is located within the first water storage chamber, and the lower part is located within the second water storage chamber. The bottom of the second water storage chamber has an outlet. A first ionization region is formed between the middle of the central high-voltage electrode and a first grounding electrode on the outer wall of the housing, and a second ionization region is formed between the bottom of the central high-voltage electrode and a second grounding electrode on the outer wall of the housing. The first and second ionization regions form a gas storage cavity. The housing has an air inlet, and an air outlet is formed between the bottom of the second water storage chamber and the housing. The air intake channel has its inlet connected to the air source and its outlet connected to the air inlet of the plasma-activated water mist generator. The sliding arc plasma source has its inlet connected to the air intake channel and its outlet connected to the second ionization region of the plasma-activated water mist generator through the air supply channel. The first ionization region and the second ionization region are dielectric barrier discharge structures; The method is as follows: the liquid flows through the water inlet channel of the plasma-activated water mist generator into the first water storage tank, and then enters the second water storage tank through the water delivery channel. The liquid comes into contact with the energized central high-voltage electrode in the first and second water storage tanks, making the liquid charged. Then, it flows out from the water outlet at the bottom of the second water storage tank into the second ionization region. The charged liquid is torn apart into droplets under the action of the electric field force. A portion of the gas enters the plasma-activated water mist generator through the gas delivery channel, where it undergoes preliminary ionization in the first discharge region to form active particles. Among these, long-lived active particles are retained after ionization, generating a large amount of plasma dominated by active oxygen substances. Another portion of the gas enters the sliding arc plasma source, where it discharges to generate a large amount of plasma dominated by nitrogen oxides. Both portions of the plasma enter the second ionization region, assisting in droplet atomization while the plasma is ionized to form a large number of short-lived active particles, which react with the droplets to generate plasma-activated water mist.

2. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, The working gas for generating plasma is air.

3. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, The liquid used to generate plasma-activated water mist is pure water or deionized water.

4. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, The bottom of the second water storage tank is provided with an inner boss and an outer boss. A water outlet is formed between the inner boss and the central high-voltage electrode, and an air outlet is formed between the outer boss and the inner platform of the shell.

5. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, The first grounding electrode and the second grounding electrode are copper metal rings.

6. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, The central high-voltage electrode is fixed inside the housing by an upper base and a lower bracket.

7. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, The top cover, the first ionization region, and the second ionization region of the shell are made of polytetrafluoroethylene, while the other parts are made of stainless steel; the first water storage tank and the second water storage tank are made of insulating ceramic.

8. The method for dual-mode online preparation of plasma electrospray according to claim 1, characterized in that, A water pump and a check valve are installed in the water inlet channel; an air pump and a check valve are installed in the air inlet channel.

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