Plasma jet nozzle, FAIMS device and application

Abstract

The invention provides a plasma jet nozzle, an FAIMS device and application. The plasma jet nozzle comprises multiple stages of spure spreaders, and every time plasma jet passes through one stage of spure spreaders, the plasma jet is divided into lateral fluid flowing along the conical surfaces of the spure spreaders and central fluid flowing along the spure spreaders. Lateral fluid flows through the rear end branches of the supporting rods to form a plurality of plasma flows which are uniformly distributed. And after the central fluid is shunted step by step, the central fluid is divided into a plurality of plasma flows in an opening at the tail end of the last-stage shunting hole. Moreover, the size of each stage of spure spreader is gradually reduced, so that the flow ratio of lateral fluid in each stage of shunting is gradually increased, the plasma flow formed in the subsequent stage has enough flow, and the flow velocity of the plasma flow in each stage is relatively close. The nozzle is relatively simple in structure and low in requirement on processing precision, so that the plasma jet forms a plurality of plasma flows with close flow speeds, and the action area of the plasma jet is greatly increased.

Description

Technical Field

[0001] The invention relates to the field of plasma jets, and in particular to a plasma jet nozzle, a FAIMS device and applications. Background Art

[0002] In recent years, atmospheric pressure plasma jets (APPJs) have gradually become a hot topic in international research due to their low temperature, high activity, easy operation, and environmental protection. APPJs have received extensive attention because they are often used in medicine, material surface treatment, and environmental protection. As a non-thermal plasma, plasma jets use inert gases as working gases (such as helium and argon).

[0003] When a certain voltage is applied, the gas is ionized to obtain a stable plasma jet. Since the plasma jet is usually ejected from a single tubular object with a plasma afterglow (plume, bullet or stream) extending from the plasma jet nozzle, the cross-sectional area of ​​the jet is usually limited to less than 5mm 2 .

[0004] In order to overcome this bottleneck problem, some technical solutions use multiple units to form a one-dimensional or two-dimensional plasma jet array. However, the jets generated by this method still have problems in consistency and uniformity, and the array structure is relatively complex. Other technical solutions use the method of expanding the range of a single jet, mostly by setting openings on the plasma jet nozzle, but this method may have problems with high processing difficulty or high processing accuracy requirements. Summary of the invention

[0005] The main purpose of the present invention is to provide a plasma jet nozzle, a FAIMS device and an application thereof, so as to solve the technical problem that the conventional method of increasing the cross-sectional area of ​​the jet has high processing difficulty or high processing precision requirement.

[0006] To achieve the above object, the present invention provides a plasma jet nozzle, comprising a fixing portion, a plurality of support rods and at least two stages of flow splitting cones; the fixing portion is coaxial with each stage of the flow splitting cones in the at least two stages of flow splitting cones and is sequentially spaced apart;

[0007] The fixing portion has a mounting hole penetrating along the axial direction, and the mounting hole is used to be nested and fixed outside the medium pipe of the plasma jet mechanism;

[0008] The flow dividing cones of each level are arranged in the same direction, and the small ends of the flow dividing cones of each level are all facing the mounting hole, and the taper angles of the flow dividing cones of each level are gradually reduced; the centers of the flow dividing cones of each level have flow dividing holes distributed along the axial direction; the diameters of the small ends of the flow dividing cones of each level are larger than the apertures of the mounting holes of the adjacent fixing parts or the apertures of the flow dividing holes of the previous level of flow dividing cones at the large ends, and the diameters of the large ends of the flow dividing cones of each level are larger than the apertures of the mounting holes of the adjacent fixing parts or the apertures of the flow dividing holes of the previous level of flow dividing cones at the large ends; the end of the flow dividing holes of the last level has a plurality of openings distributed at intervals from each other;

[0009] The fixing portion and adjacent diverter cones, and each diverter cone is connected through a corresponding group of support rods. The front end of any group of support rods is located outside the mounting hole or the corresponding diverter hole, and the rear end is located on the conical surface of the corresponding diverter cone close to the large end and is evenly distributed along the circumferential direction.

[0010] According to an embodiment of the present application, the diverter cone includes a primary diverter cone and a secondary diverter cone. The taper angle of the primary diverter cone is 45-50°, and the taper angle of the secondary diverter cone is 50-55°. The diverter holes of the primary diverter cone and the secondary diverter cone are both conical holes, and both gradually increase in size from the small end to the large end.

[0011] The diameter of the mounting hole: the diameter of the diverter hole of the first-stage diverter cone at the small end: the diameter of the diverter hole of the second-stage diverter cone at the small end is (4-4.5): (1.5-2): (1.2-1.5).

[0012] The rear end of any group of support rods is located at the outer edge of the large end of the conical surface of the corresponding diverter cone.

[0013] According to an implementation manner of the present application, the height of the primary diverter cone: the distance between the primary diverter cone and the secondary diverter cone: the height of the secondary diverter cone is (3 to 3.5): (1 to 1.5): (2 to 2.3).

[0014] According to an embodiment of the present application, the distance between the primary splitter cone and the fixing portion can be adjusted.

[0015] According to an embodiment of the present application, the fixing portion is an elastic and flexible fixing portion having an insertion hole arranged along the axial direction, and the front end of the supporting rod of the corresponding group extends into the insertion hole for fixing.

[0016] According to an embodiment of the present application, the corresponding group of support rods between the fixing portion and the primary splitter cone includes an upper support rod, a lower support rod and an elastic fixing sleeve.

[0017] The top of the upper support rod is connected to the fixing part, and the bottom has an upper matching part. The bottom of the lower support rod is connected to the primary diverter cone, and the top has a lower matching part. The upper matching part and the lower matching part can move along the axial direction and form a rod-shaped structure after being fitted. The elastic fixing sleeve is fixed on the rod-shaped structure.

[0018] The present application also provides a FAIMS device, including a power supply, a discharge needle, a dielectric tube, the above-mentioned plasma jet nozzle and a gas source.

[0019] The discharge needle is electrically connected to the power source.

[0020] The dielectric tube is sleeved outside the discharge needle, and the bottom of the dielectric tube is flush with the tip of the discharge needle.

[0021] The plasma jet nozzle is nested and fixed outside the medium pipe.

[0022] The gas source is connected to the medium pipe and the carrier gas is introduced.

[0023] The present application also provides an application of the above-mentioned FAIMS device in sterilization and water treatment.

[0024] According to an embodiment of the present application, the application of the FAIMS device in sterilization includes:

[0025] The material to be sterilized is placed under the plasma jet nozzle and maintained for 30-90 seconds to complete the sterilization; wherein, the loading voltage of the discharge needle is 10kV-16kV, the frequency of the loading voltage is 9.8kHz, and the flow rate of the carrier gas is 5.4SLM-8.6SLM.

[0026] According to the implementation mode of the present application, the application of the FAIMS device in water treatment includes:

[0027] The water to be treated is placed under the plasma jet nozzle for 30-180 seconds, wherein the loading voltage of the discharge needle is 10 kV-12 kV, the frequency of the loading voltage is 9.8 kHz, and the flow rate of the carrier gas is 5.4 SLM-8.6 SLM.

[0028] The above-mentioned plasma jet nozzle includes a multi-stage diverter cone. Each time the plasma jet passes through a stage of diverter cone, it is diverted into a lateral fluid flowing along the conical surface of the diverter cone and a central fluid flowing along the diverter hole. The lateral fluid flows through the rear end of the support rod and forks to form multiple evenly distributed plasma flows. After the central fluid is diverted step by step, it is divided into multiple plasma flows in the opening at the end of the last stage of the diverter hole. Moreover, the size of the diverter cones at each stage is reduced step by step, so that the flow rate proportion of the lateral fluid in each stage of diversion gradually increases, ensuring that the plasma flow formed by the subsequent levels has sufficient flow, thereby ensuring that the flow rate of the plasma flow at each level is relatively close. The above-mentioned plasma jet nozzle has a relatively simple structure and does not require high processing precision, so that the plasma jet forms multiple plasma flows with similar flow rates, greatly increasing the effective area of ​​the plasma jet, and the plasma distribution is relatively uniform within the effective range. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 is the positional relationship between the plasma jet nozzle, the dielectric tube and the discharge needle in one embodiment of the present application;

[0031] Figure 2 It is a structural schematic diagram, a discharge image, and a discharge voltage-current waveform diagram of a FAIMS device according to an embodiment of the present application;

[0032] Figure 3 1 is a discharge image of a double-layer nozzle structure in which the plasma of a FAIMS device according to one embodiment of the present application is divided into three jets; (b) a bottom view of the discharge image; (c) a discharge image of a single dielectric tube without a nozzle connection;

[0033] Figure 4 It is the discharge image of the plasma jet nozzle and the change of jet length under different applied voltages of one embodiment of the present application, and the change of three types of jet lengths;

[0034] Figure 5 is a discharge image of a plasma jet nozzle and a change in jet length at different gas flow rates according to an embodiment of the present application (applied voltage: 16 kV, voltage frequency: 9.8 kHz), (b) changes in the length of three types of jets;

[0035] Figure 6is a plasma jet emission spectrum of a plasma jet nozzle according to an embodiment of the present application;

[0036] Figure 7 is a distribution diagram of active materials at different voltages according to an embodiment of the present application;

[0037] Figure 8 is a distribution diagram of active substances at different gas flow rates according to an embodiment of the present application;

[0038] Fig. 9 This is a diagram of the color development area of ​​starch potassium iodide calculated using Photoshop in one embodiment of the present application;

[0039] Fig.10 is a color development area diagram of KI-starch with and without a nozzle under different experimental conditions in one embodiment of the present application;

[0040] Fig.11 is a distribution diagram of Escherichia coli inactivation according to an embodiment of the present application;

[0041] Fig.12 is the result of Escherichia coli colony count according to one embodiment of the present application;

[0042] Fig.13 is a SEM photograph of Escherichia coli according to one embodiment of the present application;

[0043] Fig.14 is a numerical simulation diagram of the front cross section of a plasma jet nozzle according to an embodiment of the present application;

[0044] Fig.15 is a longitudinal cross-sectional distribution diagram of an embodiment of the present application;

[0045] Fig.16 is a bottom longitudinal section distribution diagram of an embodiment of the present application;

[0046] Fig.17 is a graph of the physical and chemical characteristics of PAW with and without a nozzle connected according to an embodiment of the present application;

[0047] Fig.18 It is a schematic structural diagram of a plasma jet nozzle according to an embodiment of the present application from different viewing angles;

[0048] Fig.19 yes Fig.18 Bottom view of the plasma jet nozzle in (a);

[0049] Fig. 20 is a schematic diagram of a plasma jet nozzle in another embodiment of the present application in a separated state from different viewing angles;

[0050] Fig.21is a schematic diagram of a plasma jet nozzle in a separated state according to another embodiment of the present application;

[0051] Fig. 22 yes Fig.21 Schematic diagram of the separation and combination states of the plasma jet nozzle.

[0052] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings.

[0053] 100, fixing part; 200, support rod; 300, primary flow dividing cone; 400, secondary flow dividing cone; 500, flow dividing hole; 110, insertion hole; 120, side channel; 130, mounting hole; 210, upper support rod; 220, lower support rod; 230, elastic fixing sleeve; 211, upper matching part; 221, lower matching part; 240, scale; 410, opening;

[0054] 10. Power supply; 20. Discharge needle; 30. Dielectric tube; 40. Gas source; DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0057] In addition, in the present invention, the descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0058] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0059] The present invention provides a plasma jet nozzle, see Figure 1 , Figures 18 to 20 ,in, Fig.18 (a) is a schematic structural diagram of a plasma jet nozzle according to an embodiment of the present application; Fig.18 (b) in the Fig.18 The plasma jet nozzle comprises a fixing portion 100, a plurality of support rods 200 and at least two stages of splitter cones.

[0060] The material of the plasma jet nozzle is an insulating material, such as a polymer material such as plastic, rubber, etc., to reduce its interference with the generation of plasma. The materials of the various parts of the plasma jet nozzle are the same or different, without limitation. Exemplarily, the materials of the various parts of the plasma jet nozzle are the same, such as plastic. It can be prepared in an integrated molding manner, such as 3D printing, injection molding. Of course, it can also be prepared by first preparing the parts and then assembling them.

[0061] As another example, the materials of the different parts of the plasma jet nozzle are different, and the corresponding parts are prepared using different materials and then assembled. For example, the fixing part 100 is made of rubber, and the other parts are made of hard plastic.

[0062] The number of levels of the diverter cone is ≥ 2, such as 2, 3, 5, etc. The front-to-back relationship of the levels of the diverter cone is defined according to the distance from the fixing portion 100 , and the diverter cone closest to the fixing portion 100 is defined as the front diverter cone, that is, the first-level diverter cone 300 .

[0063] The fixing portion 100 is coaxial with each level of the at least two levels of the diverter cones (ie, all the diverter cones) and is sequentially spaced apart.

[0064] The fixing portion 100 has a mounting hole 130 penetrating along the axial direction, and the mounting hole 130 is used to be nested and fixed outside the medium pipe of the plasma jet mechanism.

[0065] The mounting hole 130 is usually located at the center of the fixing part 100, and the outer diameter of the mounting hole 130 is adapted to the outer diameter of the medium tube. The fixing part 100 is wrapped and fixed outside the medium tube through the mounting hole 130, such as the interference fit between the two. In some cases, the tube wall of the medium tube is usually thin, so in the case of rough calculation, the diameter of the mounting hole 130 can be regarded as the inner diameter of the medium tube. A discharge needle, such as a tungsten needle, is arranged in the center of the medium tube. The discharge needle discharges under the action of the carrier gas and the loading pressure to generate a plasma jet flowing out of the medium tube.

[0066] The flow diverter cones of each level are arranged in the same direction, and the small ends of the flow diverter cones are all facing the mounting hole 130, and the taper angles of the flow diverter cones of each level are gradually reduced. The center of each level of the flow diverter cone has a flow diverter hole 500 distributed along the axial direction. The diameter of the small end of each level of the flow diverter cone is larger than the aperture of the mounting hole 130 of the adjacent fixing part 100 or the aperture of the flow diverter hole 500 of the previous level of the flow diverter cone 300 at the large end, and the diameter of the large end of each level of the flow diverter cone is larger than the aperture of the mounting hole 130 of the adjacent fixing part 100 or the aperture of the flow diverter hole 500 of the previous level of the flow diverter cone 300 at the large end. The end of the last level of the flow diverter hole 500 has a plurality of openings spaced apart from each other.

[0067] The diverter cone is a frustum structure, and the small end of the diverter cone faces the mounting hole 130. The axis of each level of the diverter cone has a diverter hole 500 passing through. Exemplarily, the diameter of each diverter hole 500 is equal. For example, the diameter at the small end of the diverter hole 500 is equal to the diameter at the large end, which is a cylindrical structure. Another exemplary embodiment is that the diameter of the diverter hole 500 gradually increases from front to back, and gradually increases in the direction from the small end to the large end, which is a trumpet-shaped structure.

[0068] The small end and the large end of the first-stage diverter cone 300 are set based on the diverter hole 500 of the fixing part 100. That is, the small end is smaller than the diameter of the diverter hole 500, and the large end is larger than the diameter of the diverter hole 500. The small end and the large end of the remaining diverter cones are set correspondingly based on the aperture of the diverter hole 500 of the previous stage at the large end. Similarly, the small end is smaller than the diameter of the diverter hole 500, and the large end is larger than the diameter of the diverter hole 500.

[0069] In some embodiments, see Fig. 20 A partition plate, such as a cross partition plate, is provided at the end of the last-stage diversion hole 500, so that four openings of the same size and shape are formed at the end of the last-stage diversion hole 500.

[0070] See also Fig.14 The principle of each level of diverter cone is similar, and the first-level diverter cone 300 is used as an example for explanation. The small end of the first-level diverter cone 300 is smaller than the diameter of the diverter hole 500, and the large end is larger than the diameter of the diverter hole 500. The diverter cone has a diverter hole 500, and the diverter hole 500 and the mounting hole 130 are coaxially arranged. In this way, a part of the plasma jet flowing out of the mounting hole 130 impacts the conical surface of the diverter cone, forming a lateral fluid flowing along the conical surface of the diverter cone. The other part passes through the diverter hole 500 to form a central fluid flowing along the diverter hole 500. That is, the first level of diversion is formed in the first-level diverter cone 300.

[0071] The central fluid then passes through the subsequent diverter cone, that is, after being diverted step by step, it is divided into multiple plasma flows in the opening at the end of the last diverter hole 500. Due to the step-by-step diversion, the trend of the plasma flow of the central fluid at each level is gradually weakened. Therefore, the diverter cone structure at each level is designed so that the proportion of the lateral fluid of each diverter cone is smaller than that of the central fluid, especially the first-level diverter cone 300, so that the plasma flow formed at the subsequent levels has sufficient flow. The taper angle of the diverter cone at each level is gradually reduced, so that the proportion of the lateral fluid in the diverter cone diversion process at each level is increased compared with the previous level of the lateral fluid, so as to compensate for the loss caused by the weakening of the total amount of plasma flow at this level, thereby ensuring that the multiple plasma flows ultimately generated by the lateral fluids of each level and the plasma fluid of the last-level diverter hole 500 have relatively large flow rates and flow rates, and the flow rates and flow rates of each plasma flow are relatively close, so that the plasma distribution is relatively uniform.

[0072] See also Fig.18 The fixing portion 100 and adjacent diverter cones, and each diverter cone is connected to each other through a corresponding group of support rods 200. The front end of any group of support rods 200 is located outside the mounting hole 130 or the corresponding diverter hole 500, and the rear end is located on the conical surface of the corresponding diverter cone close to the large end and is evenly distributed along the circumferential direction.

[0073] Each group of support rods 200 includes a plurality of support rods 200. In the support rods 200 of the corresponding group of the primary diverter cone 300 and the fixing portion 100, the front end is located outside the mounting hole 130, such as the outer edge of the fixing portion 100, to reduce or minimize the interference of the support rods 200 with the plasma jet. At the same time, the rear end thereof is located on the conical surface of the corresponding diverter cone close to the large end and is evenly distributed along the circumference. The lateral fluid on the conical surface of the primary diverter cone 300 is bifurcated after passing through the rear end of the support rod 200 to form multiple plasma flows. In some embodiments, the number of the multiple plasma flows is twice the number of the support rods 200.

[0074] In the support rods 200 of the corresponding groups of the other two adjacent diverter cones, the front end is located outside the diverter hole 500 of the previous diverter cone 300, such as the outer edge of the fixing portion 100, to reduce or minimize the interference of the support rod 200 with the plasma jet. At the same time, the rear end is located on the conical surface of the corresponding diverter cone close to the large end and is evenly distributed along the circumference, such as located at the outer edge of the large end or, such as located at a point away from the outer edge of the large end on the conical surface. In general, the support rod 200 is located as much as possible outside the area covered by the axial projection of the mounting hole 130 on the conical surface along the fixing portion 100, so as to reduce or minimize the interference of the support rod 200 with the plasma jet.

[0075] The lateral fluid on the conical surface of the subsequent stage splitter cone is bifurcated after passing through the rear end of the support rod 200 to form multiple plasma flows. In some embodiments, the number of the multiple plasma flows is twice the number of the support rods 200 or the same as the number of the support rods 200.

[0076] The above-mentioned plasma jet nozzle includes a multi-stage diverter cone. Each time the plasma jet passes through a stage of diverter cone, it is diverted into a lateral fluid flowing along the conical surface of the diverter cone and a central fluid flowing along the diverter hole 500. The lateral fluid flows through the rear end of the support rod 200 and forks to form multiple uniformly distributed plasma flows. After the central fluid is diverted step by step, it is divided into multiple plasma flows in the opening at the end of the last stage of the diverter hole 500. Moreover, the size of the diverter cones at each stage is reduced step by step, so that the flow rate of the central fluid in each stage of diversion gradually increases, ensuring that the plasma flow formed by the subsequent levels has sufficient flow, thereby ensuring that the flow rate of the plasma flow at each level is relatively close. The above-mentioned plasma jet nozzle has a relatively simple structure and does not require high processing precision, so that the plasma jet forms multiple plasma flows with similar flow rates, greatly increasing the effective area of ​​the plasma jet, and the plasma distribution is relatively uniform within the effective range.

[0077] In some embodiments, see Fig.18 The diverter cone includes a primary diverter cone 300 and a secondary diverter cone 400. The taper angle of the primary diverter cone 300 is 45-50°, and the taper angle of the secondary diverter cone 400 is 50-55°. The diverter holes 500 of the primary diverter cone 300 and the secondary diverter cone 400 are both conical holes, and both gradually increase in size from the small end to the large end.

[0078] The diameter of the mounting hole 130: the diameter of the diverter hole 500 of the first diverter cone 300 at the small end: the diameter of the diverter hole 500 of the second diverter cone 400 at the small end is (4-4.5): (1.5-2): (1.2-1.5). The rear end of any group of support rods 200 is located at the outer edge of the large end of the conical surface of the corresponding diverter cone.

[0079] The diverter cone adopts a two-stage structure, which helps to weaken the effect of the gradual reduction of the flow rate and flow velocity of the plasma fluid, so that the multiple evenly distributed plasma flows formed by the lateral fluids corresponding to each level and the plasma flow formed by the last-stage diverter hole 500 all have relatively high flow rates and flow velocities, and the flow rates and flow velocities are as close as possible, so that the plasma is evenly distributed.

[0080] The first-level splitter cone 300 and the second-level splitter cone 400 respectively select the above-mentioned taper angles, which helps the multiple plasma flows generated by the corresponding lateral fluid of the first-level splitter cone 300 and the multiple plasma flows generated by the corresponding lateral fluid of the second-level splitter cone 400 to have relatively high flow rates and flow velocities, and the flow rates and flow velocities of the two are as close as possible, so that the plasma is evenly distributed.

[0081] The rear end of the support rod 200 is located at the outer edge of the large end of the conical surface of the corresponding diverter cone, which reduces the disturbance of the plasma flow caused by the support rod 200 and facilitates the lateral fluid bifurcation to form multiple plasma flows. Exemplarily, the number of support rods 200 between the primary diverter cone 300 and the fixing part 100 is 5. The number of support rods 200 between the primary diverter cone 300 and the secondary diverter cone 400 is also 5.

[0082] In some specific embodiments, the diameter of the mounting hole is 4mm-4.5mm, the diameter of the diverter hole of the first-stage diverter cone at the small end is 1.5mm-2mm, and the diameter of the diverter hole of the second-stage diverter cone at the small end is 1.2mm-1.5mm.

[0083] In some embodiments, see Fig.18 , the height of the first-level diverter cone 300: the distance between the first-level diverter cone 300 and the second-level diverter cone 400: the height of the second-level diverter cone 400 is (3~3.5): (1~1.5): (2~2.3).

[0084] The spacing between the primary diverter cone 300 and the secondary diverter cone 400 is the distance between the large end of the primary diverter cone 300 and the small end of the secondary diverter cone 400. The height of the primary diverter cone 300 and the height of the secondary diverter cone 400 are respectively the heights along the axis. Under the above conditions, the area sizes of the primary diverter cone 300 and the secondary diverter cone 400 are reasonable, which helps to control the proportion of the lateral fluid diverted by the secondary diverter cone 400 and reduce the loss of plasma flow other than diversion between the primary diverter cone 300 and the secondary diverter cone 400, thereby ensuring that the plasma ejected from the end of the secondary diverter cone 400 has a relatively high flow rate and flow rate.

[0085] In some specific embodiments, the height of the primary diverter cone is 3 mm to 3.5 mm, the distance between the primary diverter cone and the secondary diverter cone is 1 mm to 1.5 mm, and the height of the secondary diverter cone is 2 mm to 2.3 mm.

[0086] In some embodiments, see Fig.18, the distance between the primary diverter cone 300 and the fixed part 100 is greater than the distance between the primary diverter cone 300 and the secondary diverter cone 400. The distance between the primary diverter cone 300 and the fixed part 100 is relatively large, which helps to expand the effective area of ​​the plasma, while the distance between the primary diverter cone 300 and the secondary diverter cone 400 is relatively small, which reduces the loss of the plasma flow between the primary diverter cone 300 and the secondary diverter cone 400 except for diversion.

[0087] In some embodiments, see Fig. 20 and Fig.21 The distance between the primary diverter cone 300 and the fixing portion 100 can be adjusted. By adjusting the distance between the two, the diversion ratio of the lateral fluid and the central fluid of the primary diverter cone 300 can be adjusted to a certain extent, thereby adjusting the flow rate and flow velocity of the plasma flow generated by the subsequent diverter cone.

[0088] In some embodiments, see Fig. 20 The fixing part 100 is an elastic and flexible fixing part 100. The flexible fixing part 100 has an insertion hole 110 arranged along the axial direction, and the front end of the corresponding group of support rods 200 extends into the insertion hole 110 for fixing.

[0089] The flexible fixing part 100 has good elasticity. For example, the material of the fixing part 100 is rubber, latex, etc. After the support rod 200 is inserted into the insertion hole 110, there is a large friction force between the two, and the force on the support rod 200 is relatively small. Therefore, the flexible fixing part 100 can fix the support rod 200 more firmly. The insertion hole 110 can be a through hole or a blind hole. The distance between the first-stage diverter cone 300 and the fixing part 100 is adjusted by adjusting the insertion depth of the support rod 200 in the insertion hole 110. This method has a simple structure and is easy to adjust.

[0090] In some specific embodiments, see Fig. 20 The side surface of the flexible fixing portion 100 has a side channel 120 connected to the insertion hole 110 .

[0091] Since the plasma jet nozzle is made of insulating material, and the diameter of the support rod 200 is generally relatively thin, and the friction between the support rod 200 and the flexible fixing part 100 is relatively large, and the travel is relatively long, it may break under the action of a large force during the process of directly inserting the support rod 200 into the insertion hole 110 along the axial direction. Therefore, a side opening is opened on the side of the flexible fixing part 100, and the support rod 200 is made of a polymer material such as plastic with a certain elasticity. The elasticity of the support rod 200 is combined with the deformation of the flexible fixing part 100 to press the support rod 200 into the insertion hole 110 from the side channel 120 of the flexible fixing part 100, thereby reducing the probability of the support rod 200 breaking. In some more specific embodiments, the width of the side channel 120 is smaller than the diameter of the insertion hole 110. In this way, it is ensured that the support rod 200 enters the side channel 120, and the fixing effect of the flexible fixing part 100 on the support rod 200 is ensured after the support rod 200 enters the insertion hole 110.

[0092] In some specific embodiments, see Fig. 20 , the end of the support rod 200 has a scale 240. When inserted in this way, observing the scale 240 can ensure that all the support rods 200 are inserted into the fixing part 100 to the same depth, so as to ensure that the small end of the primary diverter cone 300 is centered, that is, located in the center of the mounting hole 130. In some more specific embodiments, the scale 240 shows the distance between the primary diverter cone 300 and the fixing part 100, so that the distance between the primary diverter cone 300 and the fixing part 100 can be quickly adjusted as needed.

[0093] In some embodiments, see Fig.21 and Fig. 22 The corresponding group of support rods 200 between the fixing portion 100 and the primary splitter cone 300 includes an upper support rod 210 , a lower support rod 220 and an elastic fixing sleeve 230 .

[0094] The top of the upper support rod 210 is connected to the fixing part 100, and the bottom has an upper matching part 211. The bottom of the lower support rod 220 is connected to the primary diverter cone 300, and the top has a lower matching part 221. The upper matching part 211 and the lower matching part 221 can move along the axial direction and form a rod-shaped structure after being attached. The elastic fixing sleeve 230 is sleeved on the rod-shaped structure to be fixed.

[0095] The upper mating part 211 is the half of a complete support rod 200 separated along the axial direction, and the lower mating part 221 is the other half of a complete support rod 200 separated along the axial direction. The fitting parts of the two form a rod-like structure, and the elastic fixing sleeve is sleeved on the rod-like structure to form a fixation. The elastic fixing sleeve 230 is like a rubber ring, which is sleeved on the rod-like structure to form a fixation. The upper mating part 211 and the lower mating part 221 can move axially to adjust the axial length of the fitting part, that is, adjust the length of the support rod 200, thereby adjusting the distance between the first-stage diverter cone 300 and the fixing part 100. This adjustment method has a simple structure and is easy to adjust.

[0096] In some specific embodiments, see Fig. 22 (a)~ Fig. 22 (b) The fitting surfaces of the upper mating portion 211 and the lower mating portion 221 have serrated surfaces. This structure has an axial limiting effect, reduces the probability of axial sliding of the upper mating portion 211 and the lower mating portion 221, and improves the fixing effect.

[0097] In order to more clearly illustrate the technical solution of the plasma jet nozzle of the present application, a more detailed embodiment is described below as an example.

[0098] Example 1

[0099] The plasma jet nozzle comprises a fixing part, two groups of supporting rods, a primary flow splitter cone and a secondary flow splitter cone.

[0100] The distance between the primary diverter cone and the fixed part is 5 mm.

[0101] In the first-stage splitter cone, the diameter of the small end is 1.5 mm, the diameter of the large end is 8 mm, the height is 3.3 mm, the diameter of the splitter hole at the small end is 1.5 mm, and the diameter of the splitter hole at the large end is 2.6 mm.

[0102] The distance between the primary diverter cone and the secondary diverter cone is 1 mm.

[0103] In the secondary splitter cone, the diameter of the small end is 1.4 mm, the diameter of the large end is 6 mm, the height is 2 mm, the diameter of the splitter hole at the small end is 1.4 mm, the diameter of the splitter hole at the large end is 3 mm. The width of the cross partition in the splitter hole is 0.7 mm.

[0104] The first group of support rods is located between the primary diverter cone and the fixing part, and the diameter of the first group of support rods is 1.1 mm. The rear end of the first group of support rods is located at the outer edge of the large end of the conical surface of the primary diverter cone.

[0105] The second group of support rods is located between the primary diverter cone and the secondary diverter cone, and the diameter of the second group of support rods is 1.1 mm. The rear end of the second group of support rods is located at the outer edge of the large end of the cone surface of the secondary diverter cone.

[0106] The medium tube is a quartz tube. A quartz tube (4 mm inner diameter, 6 mm outer diameter, 30 mm long) is inserted into the plasma jet nozzle, and a tungsten needle with a diameter of 1.1 mm is located in the center of the quartz tube as a high-voltage electrode, ensuring that the tip of the tungsten needle, the end of the quartz tube and the entrance of the fixed part are on the same horizontal plane.

[0107] The present application also provides a FAIMS device, including a power supply, a discharge needle, a dielectric tube, the above-mentioned plasma jet nozzle and a gas source. The discharge needle is electrically connected to the power supply. The dielectric tube is sleeved outside the discharge needle, and the bottom of the dielectric tube is flush with the tip of the discharge needle. The above-mentioned plasma jet nozzle is nested and fixed outside the dielectric tube. The gas source is connected to the dielectric tube and a carrier gas is introduced. The present application also provides an application of the above-mentioned FAIMS device in sterilization and water treatment.

[0108] In some embodiments, the application of the FAIMS device in sterilization includes:

[0109] The material to be sterilized is placed under the plasma jet nozzle and maintained for 30-90 seconds to complete the sterilization; wherein, the loading voltage of the discharge needle is 10kV-16kV, the frequency of the loading voltage is 9.8kHz, and the flow rate of the carrier gas is 5.4SLM-8.6SLM.

[0110] In some embodiments, the application of the FAIMS device in water treatment includes:

[0111] The water to be treated is placed under the plasma jet nozzle for 30-180 seconds, wherein the loading voltage of the discharge needle is 10 kV-12 kV, the frequency of the loading voltage is 9.8 kHz, and the flow rate of the carrier gas is 5.4 SLM-8.6 SLM.

[0112] Example 2

[0113] 1.1 Measurement method

[0114] Schematic diagram of the experimental device and the plasma jet discharge image are shown in Figure 2 The plasma jet nozzle is the plasma jet nozzle of Example 1, which is completed by a light-curing 3D printer (Anycubic Phoyon M3). The position relationship between the plasma jet nozzle and the medium tube and the discharge needle is shown in FIG. Figure 1As shown. In this work, pure helium (purity of 99.999%) was used as the working gas, and the gas flow rate was controlled by a D08-1F flow display and a CS200A digital gas mass flow meter (Beijing Qixing Huachuang Electronics Co., Ltd.), and the unit was liters per minute (SLM). The experimental power supply connected to the tungsten needle was a CTP-2000K low-temperature plasma experimental power supply (Suman Plasma Technology Co., Ltd.). The voltage was measured using a P6015A high-voltage probe (Tektronix Corp., USA) and displayed on a DPO4034B oscilloscope (Tektronix Corp., USA), and the current value was measured by a Pearson current monitor (Pearson Electronics Inc. Palo Alto. CA. USA). Optical Emission spectra (OES, AvaSpec-ULS3648-USB2-RM, Avantes, Inc., USA) was used to obtain the characteristic spectrum of the jet under the plasma jet nozzle. The OES wavelength range was set between 200–825 nm. In order to estimate the plasma jet injection length, the discharge image was taken by a digital camera (Nikon D7200), using a SIGMA lens (150 mm, F2.8), the aperture was set to F5, the exposure time was 0.17 s and the sensitivity was 6400. See Figure 2 (b) and (c) are discharge images and voltage and current waveforms. Figure 2 (a) Schematic diagram of the experimental setup, (b) discharge image of the plasma jet nozzle, (c) voltage-current waveform of the device discharge (applied voltage: 12 kV, voltage frequency: 9.8 kHz, flow rate: 5.4 SLM).

[0115] 1.2 Preparation of starch potassium iodide, E. coli, and PAW (plasma treated deionized water)

[0116] Since the active substances generated by the plasma react with I- in the starch potassium iodide to generate I2, the starch solution can be made blue-purple. According to this color development method, starch potassium iodide is selected to visualize the generation and distribution of active substances in the plasma jet. The culture medium is prepared by mixing starch potassium iodide solution and agar plate in a volume ratio of 1:1. In ultrapure water, a starch potassium iodide mixed solution is prepared by mixing 10% KI solution (Sangong, Shanghai, China) and 10% starch (Sangong, Shanghai, China). In addition, the preparation of the agar plate includes adding 16g of agar per liter of ultrapure water. Finally, the obtained starch potassium iodide indicator component is poured into a culture dish (diameter 9cm, height 1.4cm) for standby use.

[0117] Escherichia coli was selected as the experimental sterilization object. A specified number of Escherichia coli was inoculated into 75 μl sterile Luria-Bertani (LB) medium (containing: 10g tryptone; 5g NaCl; 5g yeast extract; 8g agar per liter of DIW), and incubated for 16 hours at 180rpm and 37°C in a constant temperature shaking incubator. Subsequently, 100 μl of the activated bacterial solution was added to another 75 ml of LB medium, which was placed in a constant temperature shaking incubator and incubated for 6 hours. After that, a certain amount of fresh LB containing Escherichia coli (after 6h of culture) was taken and the optical density was measured by dilution using a spectrophotometer to OD600. nm = 0.2, which is the initial concentration of the experiment, containing approximately 3×10 9 Colony forming units.

[0118] In the sterilization range visualization experiment, OD600 nm = 0.2 E. coli solution was diluted 100 times, and then 0.1 ml of the diluted solution was applied to LB medium. The medium sterilized by plasma was placed in a 37°C incubator overnight. Finally, the area of ​​the sterilized area was observed and measured, and compared with the untreated control group. In addition, in the colony counting experiment, OD600 nm = 0.2 Escherichia coli liquid was taken and injected into the container and treated with plasma. Then 0.1 ml of the treated liquid was diluted to 10 according to the concentration gradient. 4 Then take 0.1 ml of the diluted bacterial solution and incubate it in an incubator overnight. Finally, calculate the total number of colonies on the culture medium.

[0119] Deionized water (DIW) was treated with plasma to obtain PAW (plasma treated deionized water). The treated DIW was immediately tested for pH and conductivity using a pH meter (LE438, Mettler-Toledo Instruments Co., Ltd., Shanghai, China) and a conductivity meter (SX-650, Shanghai Sanxin Instrument Factory, Shanghai, China). The content of hydrogen peroxide (H2O2) and nitrate (NO3 - ) concentration. The concentration of H2O2 is measured by using the stable and yellow peroxymolybdic acid compound produced by the reaction of H2O2 with ammonium molybdate tetrahydrate. Sodium hydroxide (NaOH) and NO3 - The reaction generates sodium nitrate (NaNO3) to reflect the concentration of nitric acid in the plasma RONS.

[0120] 1.3 Scanning electron microscopy (SEM) characterization of microorganisms

[0121] Scanning electron microscopy was used to observe the morphology of microorganisms before and after plasma treatment. Before treatment, 5ul of freshly cultured Escherichia coli liquid was dripped onto the silicon wafer, and then the silicon wafer was placed in a 37°C drying oven for 1 hour. After plasma treatment, the silicon wafer was placed in a 2.5% glutaraldehyde solution for fixation for 3 hours. The silicon wafer was then washed with phosphate buffered saline (0.1mol / L) and an alcohol solution to obtain the desired sample. Finally, tert-butanol vacuum drying method was used for replacement. The sample was observed using a Quanta 200FEG field emission SEM at a 20kV accelerating electric field and WD6mm.

[0122] 2. Results and Discussion

[0123] 2.1 Visualized discharge characteristics of plasma jet nozzle

[0124] The most intuitive and effective way to observe the shape distribution of plasma jets and analyze their laws is through discharge images. Figure 3 As shown in the figure, the plasma jet nozzle breaks up a single plasma jet into multiple jets to form a multi-path discharge channel. Due to the layered structure of the device, three different types of jets are ejected, namely the upper jet (i.e., the plasma fluid generated by the lateral fluid of the first-level diverter cone, 10 jets), the middle jet (i.e., the plasma fluid generated by the lateral fluid of the second-level diverter cone, 5 jets) and the lower jet (i.e., the plasma fluid generated by the central fluid of the second-level diverter cone, 4 jets). The discharge images of the plasma jet nozzle under different voltages (i.e., working voltage or loading voltage) are shown in Figure 1. Figure 4 As shown in (a). It can be clearly seen that when the operating voltage is lower than 8kV, the PIW (primary ionization wave) in the quartz tube is not fully generated and propagated. At 10kV, the first-stage diverter cone begins to gradually accumulate charge, so that the PIW (primary ionization wave) through the upper hollow cone (diverter hole of the first-stage diverter cone) reaches the lower layer, and the upper and lower layers begin to split the plasma jet, and the middle layer jet has not yet been generated. When it is above 12kV, complete SIWs (secondary ionization waves) begin to appear, the upper and middle layer jets gradually begin to split and the discharge channel becomes obvious, and the lower layer jet seems to be in a stable state. At 16kV, the uniformity of the three types of jets is improved, and the coverage area of ​​the overall jet is significantly expanded. Combined with Figure 4 The results in (b) show that as the voltage increases, the jet lengths of the upper and middle jets increase, while the length of the lower jet remains stable.

[0125] Figure 3 : (a) Discharge image of a plasma jet nozzle structure that divides plasma into three jets; (b) Bottom view of the discharge image; (c) Discharge image of a single dielectric tube without a plasma jet nozzle connected. Figure 4: (a) Discharge image of plasma jet nozzle and jet length change under different applied voltages (gas flow rate: 5.4 SLM, voltage frequency: 9.8 kHz), (b) Changes in the length of three types of jets.

[0126] Figure 5 (a) shows the discharge images under different gas flow rates. Obviously, the three types of plasma jets are very sensitive to changes in gas flow rate. When the gas flow rate reaches 1.4SLM, SIWs (secondary ionization waves) are first generated in the upper layer. When the flow rate is increased to 5.4SLM one by one, the upper jet becomes significantly longer, and the middle and lower jets gradually appear. When the flow rate continues to increase, the excessively high gas flow rate causes the jet end of the upper jet to diverge, and the jet length gradually shortens, and the same situation occurs in the middle jet. The reason may be the occurrence of turbulence. When the gas flow rate reaches turbulent conditions, the jet length will be shortened and disturbances will occur at the tip.

[0127] Interestingly, the lower jet becomes longer as the gas flow rate increases. The reason may be that the increase in gas flow rate makes the flow pressure more concentrated in the center, making the central plasma density larger. The different propagation speeds of the three types of jets are the main reason for their different jet lengths (this conclusion can be proved in the numerical model experiment below). And the design of the plasma jet nozzle structure determines the distribution of the airflow field. The upper layer first obtains the jet with the highest speed, and due to the obstruction of the support rod, the high-speed jet hits the support rod and splits into two. In addition, the jet propagation speed obtained by the lower layer is relatively small, so only one jet is generated between the support rods. It is worth mentioning that the angle between the split jets also decreases with the increase of flow rate, which may be related to the content of fluid dynamics. Due to the design of the structure, there is no obvious electrostatic interaction between adjacent SIWs (secondary ionization waves).

[0128] Electrostatic interaction is the repulsion of the same charges, which will cause repulsion between two adjacent jets, and the adjacent jets will deviate to the sides. However, no obvious deviation phenomenon is seen in the jets generated by the nozzle device, that is, the adjacent jets are still ejected in the direction set by the nozzle structure.

[0129] Figure 5 : (a) Discharge image of plasma jet nozzle and jet length change under different gas flow rates (applied voltage: 16 kV, voltage frequency: 9.8 kHz), (b) Changes in the length of three types of jets.

[0130] 2.2 OES of plasma jet nozzle

[0131] OES is often used to detect active substances produced during plasma excitation and can effectively measure each stage of plasma generation. The active substance generation process is mainly shown in the following formula.

[0132] M+e→M 1 +e(1)

[0134] MN+e→M 1 +N+e(2)

[0136] M 1 +e(+Q)→M 1 (+Q)(3)

[0138] The emission spectrum line band of this experiment is between 200 and 825 nm, which can cover all the characteristics of the characteristic spectrum lines of helium discharge. Figure 6 The emission spectra of the side and bottom jets of the plasma jet nozzle at different voltages are shown. The probe was placed 5 mm away from the side and bottom for measurement. Four different emission lines are shown: hydroxyl, oxygen atoms, helium, and nitrogen species. Hydroxyl OH lines are shown at 308.9 nm and 315.7 nm. The second positive electrode system and the first negative electrode system (N2(0,0):336.8 nm, N2(0,1):357.4 nm, 407.2nm). The two strongest helium spectral lines are at 667.9nm (He 3 1 D-2 1 P) and 706.5nm (He 3 3 S-2 3 P), others are 502.6nm and 587.6nm. Finally, the oxygen atom O is found at 777.5nm.

[0139] Figure 6 As shown in (a), the emission spectrum peak of the side jet increases with the increase of voltage, but the profile of the emission spectrum remains basically the same. The increase in voltage increases the concentration of active species, and the plasma jet produces a large amount of RONS (reactive oxide and nitrogen species).

[0140] Figure 6 (b) also shows the same pattern, but it is worth noting that the emission spectrum types at the bottom of the device are significantly reduced. This may be related to the lifetime of active particles. When the particles propagate to a farther distance, the short-lived particles disappear, while the long-lived particles can still be detected.

[0141] Figure 6Plasma jet emission spectra of plasma jet nozzles: (a) side jet of the device; (b) bottom jet of the device (gas flow rate: 5.4 SLM, voltage frequency: 9.8 kHz)

[0142] 2.3 Distribution of active substances

[0143] The strong oxidative active substances (Reactive Oxides and Nitrogen Species, ROS and RNS) generated by the plasma jet will react with starch potassium iodide to produce a color reaction. The I- in KI undergoes an oxidation-reduction reaction and is reduced to I2. I2 reacts with the starch indicator in it, thereby showing a blue color. Using this characteristic, starch potassium iodide is used as an indicator to show the scope and degree of plasma action.

[0144] like Figure 7 , the range of active substances produced by the quartz tube without a plasma jet nozzle and the device with a plasma jet nozzle were compared. The experimental conditions of both were the same (the treatment distance was 5 mm). In the same culture dish, there was no plasma jet nozzle on the left and a plasma jet nozzle on the right. It can be seen that the device connected to the plasma jet nozzle can greatly expand the range of active substances. When the plasma jet nozzle was not connected, the distribution of active substances showed a typical ring shape. When the plasma jet nozzle was connected, in the multi-discharge channel mode, the multi-jet treatment made the distribution of active substances present a regular pentagon. However, both showed a certain regularity, and the extension of the treatment time made the active substances have a larger color range and darker color. Through the longitudinal comparison, with the increase of voltage, the color range became larger without significantly changing the distribution pattern, and the starch potassium iodide staining became darker. Higher voltage means that the stronger the ionization wave, the greater the concentration of active substances produced, more RONS participate in the reaction, and the larger the diffusion range.

[0145] The distribution of active substances is closely related to the three types of jets. Figure 7 As shown in the example (a3), the color development of starch potassium iodide consists of two parts. The color development in the red ring area is caused by the upper jet, while the middle blue area is caused by the middle and lower jets of the device. This idea is Figure 8 (a1) and (a4) are also reflected. The red ring area of ​​the former is dyed darker, and the blue area of ​​the latter is dyed darker. The slow flow rate makes the upper jet longer and contacts the treatment surface earlier, while the middle and lower jets are shorter, resulting in a delay between the two.

[0146] Use the color range function of Photoshop software to estimate the dyed part and sample the colored part, such as Fig. 9 shown. Fig.10(a) and (b) give the corresponding Figure 7 and Figure 8 The area of ​​active substance coloring starch potassium iodide. It can be seen that the maximum dyeing area can reach 1017mm 2 , which is nearly five times that of the case without plasma jet nozzle under the same conditions. The increase in flow rate leads to the change of jet shape, which makes the area smaller. This shows that the device can only show the best expansion effect under certain specific conditions.

[0147] Figure 7 Distribution of active substances under different voltages (gas flow rate: 5.4 SLM, voltage frequency: 9.8 kHz, treatment distance: 5 mm). The red ring area represents the upper jet range, and the blue circle represents the middle and lower jets (a3). The green circle represents the diameter of the quartz tube (c4).

[0148] Figure 8 Distribution of active substances at different gas flow rates (applied voltage: 12 kV, voltage frequency: 9.8 kHz, treatment distance: 5 mm). The blue circular area represents the range of the middle and lower jets (a1), and the red annular area represents the upper jet (a4).

[0149] Fig. 9 Photoshop was used to calculate the color development area of ​​starch potassium iodide (the white dotted line indicates the selected area).

[0150] Fig.10 Color development area of ​​KI-starch with and without plasma jet nozzle under different experimental conditions: (a) corresponding to Figure 7 ; (b) corresponding Figure 8 .

[0151] 2.4 Use E. coli to verify the sterilization effect

[0152] Escherichia coli was used to verify the sterilization effect of the plasma jet nozzle to expand the sterilization range. Fig.11 To improve the sterilization effect of the plasma jet nozzle, the device has a good effect of expanding the sterilization range. Fig.11 and Figure 7 Compared with potassium iodide treatment of starch, the range of bacterial inactivation showed a similar pattern. Fig.11 (b4) It can also be seen that the sterilization range is composed of two parts of the jet treatment results, which is consistent with Figure 7 (a4) The results are similar.

[0153] The sterilization distribution without the plasma jet nozzle connected also showed a hollow ring. Overall, the sterilization effect improved with the increase of treatment time. In other words, there will be a blind spot in the center of the jet ejected from a single medium tube, forming a ring-shaped sterilization distribution effect. In addition to expanding the area, the plasma jet nozzle of the present application also reduces the blind spot of the jet. For example, there is no blind spot within the range covered by the jet ejected from the end of the diversion hole of the secondary diversion cone.

[0154] Similarly, as the voltage increases, the sterilization range gradually increases, because a higher concentration of RONS is produced and diffuses around. Since starch potassium iodide is more susceptible to the diffusion of this active substance in the plane, the sterilization treatment range under the same conditions is smaller than the color development range of starch potassium iodide.

[0155] Due to the different distances between the discharge paths of the plasma jet nozzle and the medium, the intensity of the ionization wave is different, resulting in some E. coli in the center of the plasma jet nozzle not being eliminated. In addition, the temperature of the culture medium under different plasma treatment times was tested. When the indoor temperature was 26.7°C, when the plasma treatment time reached 30s, 60s, 90s, and 120s, the treatment surface temperature of the culture medium reached 27.8, 28.3, 29.2, and 29.4°C. It can be seen that the generated plasma slightly increased the temperature of the culture medium, which had no effect on the inactivation of bacteria compared to the culture temperature (37°C).

[0156] Fig.11 Distribution of E. coli inactivation. In the same culture dish, there is no plasma jet nozzle on the left and a plasma jet nozzle on the right (gas flow rate: 5.4 SLM, voltage frequency: 9.8 kHz, treatment distance: 5 mm). The red ring area represents the upper jet range, and the blue circle represents the middle and lower jets (b4).

[0157] Fig.12 The results of E. coli counts of the two discharge modes at different treatment times are shown. In general, the sterilization efficiency of the device equipped with a plasma jet nozzle is higher than that of the device without a plasma jet nozzle. When the treatment time is 30s, the sterilization number of the former is nearly one log higher than that of the latter, and the difference between the two gradually increases with the increase of treatment time. When the treatment time reaches 120s, the device equipped with a plasma jet nozzle completely inactivates E. coli with a colony count of approximately 108, while the device without a plasma jet nozzle takes longer. This experiment once again verifies the advantage of the DL plasma jet nozzle in efficiently treating objects under the multi-channel discharge mode.

[0158] Fig.12Results of E. coli colony counts: comparison of loaded and unloaded plasma jet nozzles at different treatment times.

[0159] The high-energy electrons and active substances in the plasma can destroy the external structure of E. coli, thereby achieving the effect of damage and inactivation. The morphological changes of E. coli before and after treatment with the DL plasma jet nozzle were observed using SEM. Fig.13 In the experiment, the surface of untreated E. coli was smooth and intact. After plasma treatment, deformation and damage of E. coli in different forms can be observed due to the interaction between plasma and bacteria. A large number of E. coli surfaces showed wrinkles, cracks and perforations, and even the contents could be seen overflowing. Using more discharge channels means generating more high-energy electrons and free radicals, which is conducive to strengthening the interaction with bacteria.

[0160] Fig.13 SEM images of Escherichia coli: untreated control group (a) and plasma treated group (b) at an applied voltage of 12 kV. The red arrows indicate the damage to the external structure of the bacteria.

[0161] 2.4 Establishment of numerical model of plasma jet nozzle

[0162] In this paper, a numerical model is established to study the relationship between the gas flow field distribution and the helium mass fraction under the plasma jet nozzle. Fluent and Star-ccm+ software are used for simulation analysis. The turbulence model adopts the Realizable K-Epsilon model. The simulated size of the plasma jet nozzle is consistent with the actual one. The quartz tube inlet is set as the helium inlet, and the inlet boundary condition is the mass flow inlet (the mass flow rate is set to 1.47168 -5 kg / s, corresponding to a gas flow rate of 5.4SLM), and the pressure outlet is atmospheric pressure.

[0163] like Fig.14 The simulated gas flow field and helium mass fraction of the front plasma jet nozzle. It can be seen that its overall distribution is fan-shaped. The gas flows through the quartz tube to the upper layer and divides the gas flow into multiple streams. The flow rate is lost due to obstruction. However, the diameter of the middle circular hole of the first-stage diverter cone is smaller than the gas flow rate, so that the gas is compressed at a high flow rate and transferred to the second-stage diverter cone (the gas velocity reaches the maximum). However, the gas flow velocity reaching the lower layer becomes weak. With such a velocity field distribution, a Fig.14(b) Helium mass fraction distribution diagram. Its shape is basically similar to the discharge experiment results. Due to the faster flow rate in the center of the plasma jet nozzle, the helium is more concentrated below the plasma jet nozzle. In comparison, the helium content on both sides of the plasma jet nozzle is less, but both show a trend of diffusing outward. Using the PIW (primary ionization wave) in the dielectric tube, the plasma plume generated by the larger helium flow rate increases the number of surface ionization waves through the segmented structure plasma jet nozzle, which increases the propagation trend of SIWs (secondary ionization waves). Fig.14 Numerical simulation of the front cross section of a plasma jet nozzle: (a) gas flow field distribution; (b) mass fraction of helium.

[0164] To further understand the distribution, the middle of the plasma jet nozzle ( Fig.15 ) and 5 mm from the bottom of the plasma jet nozzle ( Fig.16 ). Fig.15 (a) It can be seen that the lateral flow field in the middle position is mainly dominated by the upper jet (showing a petal shape). The support rod makes the jet dispersed. Fig.15 (b) The active substances have been shown to diffuse around. When the airflow reaches the bottom of the plasma jet nozzle, Fig.16 (a) The flow field distribution of three types of jets can be observed. The upper jet has a wider diffusion range, and the middle jet and the lower jet are also visible. Fig.16 (b) Experimental results Fig.16 (c) is similar. It can be observed that the active substances are basically concentrated in the center. This is because in places with high flow rates, the active substances are blown away faster, making the color change reaction difficult. On the contrary, in places with low flow rates, the reaction time becomes sufficient, making the color change reaction simple. Fig.15 Distribution of the middle longitudinal section: (a) gas flow field distribution; (b) mass fraction of helium. Fig.16 Bottom longitudinal section distribution: (a) gas flow field distribution; (b) mass fraction of helium; (c) visualization of active substances (demarcating the jet ranges of the three types of jets).

[0165] 2.5Physical and Chemical Properties of PAW (Plasma Treated Deionized Water)

[0166] Due to the presence of RONS, when APPJs interact with water or solutions, PAW (plasma treated deionized water) is produced, which is widely used in water purification and biomedicine. The chemical activity in PAW (plasma treated deionized water) is closely related to the active substances in water. The chemical reaction of this plasma-liquid interaction is determined by the active oxygen and nitrogen species, usually NO2, NO3, H2O2, O3. In order to further understand the advantages of plasma jet nozzles in expanding the range of active substances and improving the reaction efficiency of active substances in PAW (plasma treated deionized water), as Fig.17 The physical and chemical properties (pH value, conductivity, H2O2 and HNO3 concentration) of PAW (plasma treated deionized water) treated by a single medium tube and a plasma jet nozzle are given. 10 ml of DIW was injected into a culture dish, and the bottom of the plasma jet nozzle was kept 5 mm away from the liquid surface. The time from the completion of PAW (plasma treated deionized water) treatment to the detection was no more than 2 minutes. Fig.17 (a) and (b) show that under the same conditions, from 0 to 180s, the pH value of DIW treated with a plasma jet nozzle decreased and the conductivity increased significantly compared to the single medium tube without a plasma jet nozzle. This indicates that the diffusion of active substances in the plasma-liquid interaction reaction improved the physicochemical properties of PAW (plasma treated deionized water). At the same time, the concentrations of two RONS in PAW (plasma treated deionized water) were also measured. Fig.17 (c) and (d) give the H2O2 and HNO3 concentrations of DIW at different treatment times in two cases. When the treatment time is 90s, the HNO3 concentration is 39.3μM when the plasma jet nozzle is connected, while it is 20.44μM when the plasma jet nozzle is not connected. In addition, when the H2O2 concentration is 90s in the PAW (plasma treated deionized water) treatment time, the former is 64.56μM, while the latter is 53.87μM. In summary, compared with a single plasma bullet, the multiple jets generated by the plasma jet nozzle are shot into the water. The increase in discharge channels expands the plasma discharge area and increases the plasma-liquid reaction area. This not only increases the activation area of ​​PAW (plasma treated deionized water), increases the concentration of active substances, but also improves the energy utilization efficiency. Fig.17 Physicochemical characteristics of PAW (plasma treated deionized water) with and without the plasma jet nozzle connected: (a) pH; (b) conductivity; (c) NO3 - concentration; (d) H2O2 concentration.

[0167] 3. Conclusion

[0168] In summary, a plasma jet nozzle was designed and loaded on a medium tube. This novel device can break up a single plasma jet into multiple discrete streams by using a layered structure. The generation of multiple jets makes it possible to expand the plasma area. Starch potassium iodide was used to characterize the range of plasma active substances. The results showed that the device can expand the single jet area several times, up to 1017mm 2 In addition, the experiment of inactivating E. coli also proved that the device has a good sterilization effect in a large range. Compared with the traditional single-beam plasma bullet, the generation of multiple jets is conducive to the diffusion of active substances and improves the activation efficiency of PAW (plasma treated deionized water). This segmented structure maximizes the use efficiency of PIW (primary ionization wave) and improves the utilization rate of energy.

[0169] The above technical solutions of the present invention are only preferred embodiments of the present invention, and the patent scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A plasma jet nozzle, characterized in that: It comprises a fixing part, a plurality of support rods and at least two stages of diverter cones; the fixing part is coaxial with the diverter cones of each stage in the at least two stages of diverter cones and is arranged in sequence at intervals; The fixing portion has a mounting hole penetrating along the axial direction, and the mounting hole is used to be nested and fixed outside the medium pipe of the plasma jet mechanism; The flow dividing cones of each level are arranged in the same direction, and the small ends of the flow dividing cones of each level are all facing the mounting hole, and the taper angles of the flow dividing cones of each level are gradually reduced; the centers of the flow dividing cones of each level have flow dividing holes distributed along the axial direction; the diameters of the small ends of the flow dividing cones of each level are larger than the apertures of the mounting holes of the adjacent fixing parts or the apertures of the flow dividing holes of the previous level of flow dividing cones at the large ends, and the diameters of the large ends of the flow dividing cones of each level are larger than the apertures of the mounting holes of the adjacent fixing parts or the apertures of the flow dividing holes of the previous level of flow dividing cones at the large ends; the end of the flow dividing holes of the last level has a plurality of openings distributed at intervals from each other; The fixing portion and adjacent diverter cones, and each diverter cone is connected through a corresponding group of support rods. The front end of any group of support rods is located outside the mounting hole or the corresponding diverter hole, and the rear end is located on the conical surface of the corresponding diverter cone close to the large end and is evenly distributed along the circumferential direction.

2. The plasma jet nozzle according to claim 1, characterized in that: The diverter cone includes a primary diverter cone and a secondary diverter cone; the taper angle of the primary diverter cone is 45-50°, and the taper angle of the secondary diverter cone is 50-55°; the diverter holes of the primary diverter cone and the secondary diverter cone are both conical holes, and gradually increase in size from the small end to the large end; The diameter of the mounting hole: the diameter of the diverter hole of the first-stage diverter cone at the small end: the diameter of the diverter hole of the second-stage diverter cone at the small end is (4-4.5): (1.5-2): (1.2-1.5); The rear end of any group of support rods is located at the outer edge of the large end of the conical surface of the corresponding diverter cone.

3. The plasma jet nozzle according to claim 2, characterized in that: The height of the primary diverter cone: the distance between the primary diverter cone and the secondary diverter cone: the height of the secondary diverter cone is (3-3.5): (1-1.5): (2-2.3).

4. The plasma jet nozzle according to claim 2, characterized in that: The distance between the primary splitter cone and the fixing portion is adjustable.

5. The plasma jet nozzle according to claim 4, characterized in that: The fixing portion is a flexible fixing portion with elasticity; the flexible fixing portion has an insertion hole arranged along the axial direction, and the front end of the supporting rod of the corresponding group extends into the insertion hole for fixing.

6. The plasma jet nozzle according to claim 4, characterized in that: The corresponding group of support rods between the fixing portion and the first-stage splitter cone includes an upper support rod, a lower support rod and an elastic fixing sleeve; The top of the upper support rod is connected to the fixed part, and the bottom has an upper matching part; the bottom of the lower support rod is connected to the first-level diversion cone, and the top has a lower matching part; the upper matching part and the lower matching part can move axially and form a rod-shaped structure after being fitted; the elastic fixing sleeve is mounted on the rod-shaped structure to be fixed.

7. A FAIMS device, characterized in that: include: power supply; A discharge needle, electrically connected to the power source; A dielectric tube is sleeved outside the discharge needle, and the bottom of the dielectric tube is flush with the tip of the discharge needle; The plasma jet nozzle according to any one of claims 1 to 6, which is nested and fixed outside the medium pipe; A gas source is connected to the medium tube and introduced with carrier gas.

8. Use of the FAIMS device as claimed in claim 7 in sterilization and water treatment.

9. The use according to claim 8, characterized in that: The application of the FAIMS device in sterilization includes: The material to be sterilized is placed under the plasma jet nozzle and maintained for 30-90 seconds to complete the sterilization; wherein, the loading voltage of the discharge needle is 10kV-16kV, the frequency of the loading voltage is 9.8kHz, and the flow rate of the carrier gas is 5.4SLM-8.6SLM.

10. The use according to claim 9, characterized in that: The application of the FAIMS device in water treatment includes: placing the water to be treated under the plasma jet nozzle for 30-180 seconds, wherein the loading voltage of the discharge needle is 10kV-12kV, the frequency of the loading voltage is 9.8kHz, and the flow rate of the carrier gas is 5.4SLM-8.6SLM.

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