Plasma irradiation device and method for producing plasma-treated liquid

Abstract

In the present invention, an atmospheric pressure plasma irradiation apparatus (10) comprises: a storage part (184) for storing a liquid being processed, a bottom surface (184b) of the storage part being provided with a discharge hole (184c) for discharging stored liquid being processed; a plasma generator (20) for generating a plasma to be irradiated onto the liquid being processed stored in the storage part (184); and a first or a second bar-shaped member (187), (188) that is provided upright on the bottom surface (184b) of the storage part (184) and that guides liquid being processed stored in the storage part (184) to the discharge hole (184c).

Description

[Technical field]

[0001] The present disclosure relates to a technique for irradiating a processing object with plasma. [Background technology]

[0002] Patent document 1 describes an atmospheric pressure plasma processing apparatus comprising a flow path through which a liquid to be irradiated with plasma flows, a supply unit for causing the liquid to flow through the flow path at a constant flow rate, an irradiation block provided within the flow path, and a plasma head for irradiating the liquid to be irradiated with plasma gas in the irradiation block. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2020 / 026324 A1 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the atmospheric pressure plasma processing apparatus described in Patent Document 1 does not mention how to quickly drain the irradiated liquid stored in the irradiation block from the irradiation block without leaving the liquid therein.

[0005] An object of the present disclosure is to provide a technique that enables a liquid to be treated stored in a storage container to be quickly discharged from the storage container without remaining in the storage container. [Means for solving the problem]

[0006] In order to achieve the above-mentioned objective, the plasma irradiation device of the present disclosure comprises a storage container for storing the liquid to be treated and having a drainage hole on the bottom surface for draining the stored liquid to be treated, a plasma generating device for generating plasma that is irradiated to the liquid to be treated stored in the storage container, and a bar-shaped drainage promotion section erected on the bottom surface of the storage container for guiding the liquid to be treated stored in the storage container to the drainage hole. Effect of the Invention

[0007] According to the present disclosure, it is possible to quickly drain the liquid to be treated stored in the storage container from the storage container without leaving the liquid in the storage container. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of an atmospheric pressure plasma irradiation device. [Diagram 2] FIG. 2 is an exploded view of the plasma generating device. [Diagram 3] FIG. 2 is an exploded view of the plasma generating device. [Figure 4] FIG. 2 is a cross-sectional view of a plasma generating device. [Diagram 5] FIG. 2 is a perspective view of an atmospheric pressure plasma irradiation device. [Figure 6] FIG. 2 is a side view of the atmospheric pressure plasma irradiation device. [Figure 7] FIG. 2 is a side view of the atmospheric pressure plasma irradiation device. [Figure 8] FIG. 2 is a perspective view of an atmospheric pressure plasma irradiation device. [Figure 9] FIG. 2(a) is a perspective view of an irradiation block, and FIG. 2(b) is a cross-sectional perspective view taken along line AA of the irradiation block. [Figure 10] 10A is a perspective view of an irradiation block different from that in FIG. 9, and FIG. 10B is a cross-sectional perspective view taken along line BB of the irradiation block. [Figure 11] FIG. 2 is a block diagram of a control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] 1 shows an atmospheric plasma irradiation device 10 according to an embodiment of the present disclosure. The atmospheric plasma irradiation device 10 is a device for irradiating a culture liquid (an example of a "liquid to be treated") with plasma under atmospheric pressure, and includes a plasma generating device 20, a cover housing 22, an opening / closing mechanism 24, a stage 26, an elevator device 28, a purge gas supply mechanism 32 (see FIG. 5), a concentration detection mechanism 34, an exhaust mechanism 36, and a control device 38 (see FIG. 11). The width direction of the atmospheric plasma irradiation device 10 is referred to as the X direction, the depth direction of the atmospheric plasma irradiation device 10 is referred to as the Y direction, and the direction perpendicular to the X direction and the Y direction, that is, the up-down direction, is referred to as the Z direction.

[0011] As shown in Figures 2 to 4, the plasma generator 20 includes a cover 50, an upper block 52, a lower block 54, a pair of electrodes 56, and a nozzle block 58. The cover 50 is generally in the shape of a covered rectangular cylinder, and the upper block 52 is disposed inside the cover 50. The upper block 52 is generally in the shape of a rectangular parallelepiped, and is made of ceramic. A pair of cylindrical recesses 60 are formed on the lower surface of the upper block 52.

[0012] The lower block 54 is also generally rectangular and made of ceramic. A recess 62 is formed on the upper surface of the lower block 54, and the recess 62 is composed of a pair of cylindrical recesses 66 and a connecting recess 68 that connects the pair of cylindrical recesses 66. The lower block 54 is fixed to the lower surface of the upper block 52 in a state where it protrudes from the lower end of the cover 50, and the cylindrical recess 60 of the upper block 52 and the cylindrical recess 66 of the lower block 54 are connected to each other. The cylindrical recess 60 and the cylindrical recess 66 have approximately the same diameter. A slit 70 is formed on the bottom surface of the recess 62, which penetrates the lower surface of the lower block 54.

[0013] Each of the pair of electrodes 56 is disposed in a cylindrical space defined by the cylindrical recess 60 of the upper block 52 and the cylindrical recess 66 of the lower block 54. The outer diameter of the electrode 56 is smaller than the inner diameters of the cylindrical recesses 60, 66. The nozzle block 58 is generally flat and fixed to the lower surface of the lower block 54. The nozzle block 58 is formed with an ejection port 72 that communicates with the slit 70 of the lower block 54, and the ejection port 72 penetrates the nozzle block 58 in the vertical direction.

[0014] The plasma generator 20 further includes a processing gas supply device 74 (see FIG. 11). The processing gas supply device 74 is a device that supplies a processing gas obtained by mixing an active gas such as oxygen and an inert gas such as nitrogen at an arbitrary ratio, and is connected to the cylindrical space defined by the cylindrical recesses 60, 66 and to the upper part of the connecting recess 68 via piping (not shown). As a result, the processing gas is supplied into the recess 62 from the gap between the electrode 56 and the cylindrical recess 66 and the upper part of the connecting recess 68.

[0015] With this structure, the plasma generator 20 ejects plasma from the nozzle 72 of the nozzle block 58. More specifically, a processing gas is supplied to the inside of the recess 62 by the processing gas supply device 74. At this time, a voltage is applied to the pair of electrodes 56 in the recess 62, and a current flows between the pair of electrodes 56. This causes a discharge between the pair of electrodes 56, and the discharge converts the processing gas into plasma. The plasma is then ejected from the nozzle 72 through the slit 70.

[0016] 5, the cover housing 22 includes an upper cover 76 and a lower cover 78. The upper cover 76 is generally cylindrical with a lid, and a through hole (not shown) having a shape corresponding to the lower block 54 of the plasma generator 20 is formed in the lid of the upper cover 76. The cover 50 of the plasma generator 20 is fixed in an upright state to the lid of the upper cover 76 so as to cover the through hole. Therefore, the lower block 54 and the nozzle block 58 of the plasma generator 20 protrude toward the inside of the upper cover 76 so as to extend in the Z direction. As a result, the plasma generated by the plasma generator 20 is ejected in the Z direction from the ejection port 72 of the nozzle block 58 toward the inside of the upper cover 76.

[0017] Furthermore, roughly rectangular through-holes (not shown) are formed at three equally spaced positions on the side surface of the upper cover 76, and transparent glass plates 80 are disposed so as to cover the through-holes. This makes it possible to visually check the inside of the upper cover 76 through the glass plates 80.

[0018] The lower cover 78 of the cover housing 22 is generally disk-shaped and is fixed to a housing (not shown) of a mounting portion on which the atmospheric plasma irradiation device 10 is mounted. The outer diameter of the lower cover 78 is larger than the outer diameter of the upper cover 76, and an annular packing 82 having the same diameter as the upper cover 76 is disposed on the upper surface of the lower cover 78. Then, by sliding the upper cover 76 downward by the opening / closing mechanism 24, the upper cover 76 comes into close contact with the packing 82, and the inside of the cover housing 22 is sealed.

[0019] More specifically, the opening / closing mechanism 24 includes a pair of slide mechanisms 86 and an air cylinder 88, as shown in Figs. 6 and 7. Each slide mechanism 86 includes a support shaft 90 and a slider 92. The support shaft 90 is erected on the housing of the placement unit so as to extend in the Z direction. The slider 92 has a generally cylindrical shape and is fitted onto the support shaft 90 so as to be slidable in the axial direction of the support shaft 90. The upper cover 76 is held by the slider 92 with an upper bracket 96 and a lower bracket 98. This allows the upper cover 76 to slide in the Z direction, that is, in the up-down direction.

[0020] The air cylinder 88 includes a rod 100, a piston (not shown), and a cylinder 102. The rod 100 is disposed so as to extend in the Z direction, and is fixed at its upper end to the upper cover 76. A piston is fixed to the lower end of the rod 100. The piston is fitted into the cylinder 102 from its upper end, and moves slidably inside the cylinder 102. The cylinder 102 is fixed at its lower end to the housing of the placement unit, and a predetermined amount of air is sealed inside the cylinder 102.

[0021] As a result, the air cylinder 88 functions as a damper, preventing the upper cover 76 from suddenly descending. The air pressure inside the cylinder 102 is set to a pressure that can be compressed by the weight of the integral parts that slide together with the upper cover 76, that is, the upper cover 76, the plasma generator 20, the slider 92, etc. In other words, when the operator releases the upper cover 76 in a raised state, the upper cover 76 descends due to the weight of the upper cover 76, etc. Then, the upper cover 76 comes into close contact with the packing 82 of the lower cover 78, and the inside of the cover housing 22 is sealed by the upper cover 76 and the lower cover 78, as shown in FIG. 8.

[0022] Furthermore, when the operator lifts the upper cover 76, the inside of the cover housing 22 is opened. A magnet 106 (see FIG. 1) is fixed to the upper surface of the upper cover 76, and when the upper cover 76 is lifted, the magnet 106 is attached to the housing of the placement part. In this way, by attracting the magnet 106 to the housing of the placement part, the state in which the upper cover 76 is lifted, that is, the state in which the cover housing 22 is open, is maintained.

[0023] The stage 26 is generally disk-shaped, and the irradiation block 180 is placed on the upper surface of the stage 26. The outer diameter of the stage 26 is smaller than the outer diameter of the lower cover 78. The stage 26 is disposed on the upper surface of the lower cover 78.

[0024] The irradiation block 180 is used to store the liquid to be treated delivered by the liquid delivery tube 120 and generate a plasma-treated liquid by irradiating the stored liquid to be treated with plasma ejected from the plasma generator 20. The generated plasma-treated liquid is discharged from the irradiation block 180 by the drainage tube 122.

[0025] The liquid to be treated is supplied to the irradiation block 180 in the cover housing 22 by a liquid feed tube 120 using a pump (not shown) from a liquid feed section (not shown) provided outside the cover housing 22. The plasma treatment liquid generated in the irradiation block 180 is drained from the irradiation block 180 by a liquid drain tube 122 using a pump (not shown) and stored in a temporary storage bottle (not shown) provided outside the cover housing 22. Therefore, through holes 134 and 136 through which the liquid feed tube 120 and the liquid drain tube 122 pass, respectively, are formed on the side surface of the lower cover 78.

[0026] Fig. 9 shows a schematic configuration of the irradiation block 180. Fig. 9(a) is a perspective view showing the overall appearance of the irradiation block 180, and Fig. 9(b) is a cross-sectional perspective view taken along line BB in Fig. 9(a). The direction from left to right is the direction in which the liquid to be treated flows.

[0027] The irradiation block 180 is made of ceramic and is composed of an irradiation block main body 181 having a generally rectangular parallelepiped shape. The long side direction of the irradiation block 180 is the X direction, and the short side direction is the Y direction. The irradiation block main body 181 is formed with a groove portion 183 and a storage portion 184, the surface of which facing the plasma generator 20 is open when the irradiation block main body 181 is installed in the cover housing 22.

[0028] The groove 183 has a U-shape in YZ cross section that opens upward. A bottom surface 183a constituting the groove 183 is curved. The YZ cross section of the groove 183 is slightly narrower than the cross-sectional shape of the liquid supply tube 120 (see FIG. 1), and the liquid supply tube 120, which is flexible, is fitted into the groove 183 to fix the liquid supply tube 120.

[0029] The storage section 184 stores the liquid to be treated for plasma irradiation. The storage section 184 is formed of a cylindrical recess having a side surface 184a and a bottom surface 184b. The bottom surface 184b of the storage section 184 is formed to be located lower than the bottom surface 183a of the groove section 183. The bottom surface 184b of the storage section 184 is further formed with a drainage hole 184c for discharging the plasma-treated liquid generated by irradiating the liquid to be treated with plasma from the storage section 184 to the outside. The bottom surface 184b is an inclined surface that slopes downward from the side surface 184a toward the drainage hole 184c. This is to realize a function of quickly discharging the plasma-treated liquid from the storage section 184 when discharging the plasma-treated liquid, and a function of preventing as much as possible a state in which a part of the plasma-treated liquid remains in the storage section 184 without being discharged.

[0030] Furthermore, a first bar-shaped member 187 is placed on the bottom surface 184b at a length and position equivalent to the diameter of the circular bottom surface 184b. The first bar-shaped member 187 is generally rectangular parallelepiped, and the length of each short side of the top surface and bottom surface is shorter than the diameter of the drainage hole 184c. In other words, when an operator looks at the top surface of the first bar-shaped member 187 from above in the Z direction, a part of the drainage hole 184c can be seen. The first bar-shaped member 187 is for facilitating the drainage of the liquid to be treated (including the plasma-treated liquid) stored in the storage section 184 from the drainage hole 184c. If the entire drainage hole 184c is blocked by the first bar-shaped member 187, the drainage is inhibited. When the drainage of the liquid stored in the storage section 184 reaches the end, the liquid may be repelled at the entrance of the drainage hole 184c or attracted to the corners of the bottom surface 184b, preventing the liquid from being drained, and some of the liquid may remain in the storage section 184. However, when the first bar-shaped member 187 is placed as described above, the liquid repelled at the entrance of the drainage hole 184c or attracted to the corners of the bottom surface 184b and remaining on the bottom surface 184b flows down the first bar-shaped member 187 and is guided to the drainage hole 184c and drained. This effect is further enhanced by the bottom surface 184b being an inclined surface that slopes downward from the side surface 184a toward the drainage hole 184c.

[0031] The first bar-shaped member 187 is made of ceramics like the irradiation block 180, but is formed separately from the irradiation block 180. This is only because it is difficult to form the first bar-shaped member 187, which protrudes upward from the bottom surface 184b, integrally with the bottom surface 184b using ceramics. Therefore, the first bar-shaped member 187 may be formed integrally with the irradiation block 180.

[0032] Needless to say, the height of the first bar-shaped member 187 is lower than the height of the side surface 184a. If the height of the first bar-shaped member 187 were equal to or greater than the height of the side surface 184a, the liquid to be treated that flows into the storage section 184 would be blocked by the first bar-shaped member 187.

[0033] FIG. 10 shows an irradiation block different from that shown in FIG. 9. As can be seen by comparing FIG. 10 and FIG. 9, the irradiation block 180 in FIG. 10 differs in that a second bar-shaped member 188 is used instead of the first bar-shaped member 187 of the irradiation block 180 in FIG. 9. The other configurations are the same between FIG. 10 and FIG. 9. The second bar-shaped member 188 is placed at a length and position corresponding to the radius of the circular bottom surface 184b. In this way, it has been confirmed by experiments that the same effect as the first bar-shaped member 187 can be obtained even when the second bar-shaped member 188, which is half the first bar-shaped member 187, is placed so as to extend from the drainage hole 184c to the side surface 184a.

[0034] The irradiation block main body 181 has a discharge part 186 in addition to the above configuration. The discharge part 186 is formed on the lower surface 181a of the irradiation block main body 181, protruding downward from a position including the drainage hole 184c of the storage part 184. The discharge part 186 has a base part 186a, a flange part 186b, and a discharge locking part 186c, and is integrally formed with each of the components 186a to 186c connected downward. In addition, a through hole 186d is formed in the center of the discharge part 186 in the Z direction, and communicates with the drainage hole 184c of the storage part 184.

[0035] The part of the outer peripheral surface of the discharge part 186 that is continuous with the lower surface 181a of the irradiation block main body part 181 is the base part 186a. The diameter of the outer circumference of the discharge lock part 186c formed below the base part 186a with the flange part 186b sandwiched therebetween is larger than the diameter of the drainage tube 122 (see FIG. 1). The outer diameter of the upper part 186c1 of the discharge lock part 186c is smaller than the outer diameter of the discharge lock part 186c. As a result, when the flexible drainage tube 122 is fitted up to the upper part 186c1, the drainage tube 122 is deformed along the outer circumference of the discharge lock part 186c, and the drainage tube 122 is fixed. The base part 186a is fitted into the cutout part 26a of the stage 26 (see FIG. 1), whereby the irradiation block 180 is fixed to the stage 26. In this manner, since the irradiation block 180 is not fixed using a fixture, it can be easily attached to and detached from the stage 26 .

[0036] As shown in Fig. 7, the lifting device 28 includes a support rod 112, a rack 114, a pinion 116, and an electromagnetic motor 117 (see Fig. 11). A through hole (not shown) penetrating in the vertical direction is formed in the lower cover 78, and the support rod 112 is inserted into the through hole. The outer diameter of the support rod 112 is smaller than the inner diameter of the through hole, and the support rod 112 is movable in the vertical direction, i.e., in the Z direction. The lower surface of the stage 26 is fixed to the upper end of the support rod 112.

[0037] The rack 114 is fixed to the outer circumferential surface of the portion of the support rod 112 extending downward from the lower cover 78 so as to extend in the axial direction of the support rod 112. The pinion 116 is meshed with the rack 114 and rotates by driving the electromagnetic motor 117. The pinion 116 is rotatably held by the housing of the placement unit. With this structure, the pinion 116 rotates by driving the electromagnetic motor 117, and the support rod 112 moves in the Z direction, and the stage 26 rises and falls. A measurement rod 118 is erected on the upper surface of the lower cover 78 next to the stage 26. A scale is marked on the outer circumferential surface of the measurement rod 118, and the scale makes it possible to visually check the height of the stage 26 in the Z direction, that is, the amount of rise and fall of the stage 26.

[0038] As shown in Fig. 5, the purge gas supply mechanism 32 includes four air joints 130 (three are shown in the figure) and a purge gas supply device 132 (see Fig. 11). The four air joints 130 are provided at four equally spaced positions on the upper end of the side surface of the upper cover 76, and each air joint 130 opens into the inside of the upper cover 76. The purge gas supply device 132 is a device that supplies an inert gas such as nitrogen, and is connected to each air joint 130 via a pipe (not shown). With this structure, the purge gas supply mechanism 32 supplies an inert gas to the inside of the upper cover 76.

[0039] The concentration detection mechanism 34 includes an air joint 140, a pipe 142, and a detection sensor 144 (see FIG. 11). A through hole (not shown) is formed in the lower cover 78, which communicates with the upper surface and the side surface of the lower cover 78. An opening 146 of the through hole on the upper surface side of the lower cover 78 is located inside the packing 82. Meanwhile, the air joint 140 is connected to the opening of the through hole on the side surface side of the lower cover 78. The detection sensor 144 is a sensor that detects the oxygen concentration, and is connected to the air joint 140 via the pipe 142. With this structure, the concentration detection mechanism 34 detects the oxygen concentration inside the cover housing 22 when the cover housing 22 is sealed.

[0040] As shown in FIG. 1, the exhaust mechanism 36 includes an L-shaped pipe 150, a connecting pipe 152, and a main pipe 154. As shown in FIG. 7, a duct port 160 is formed in the lower cover 78, which opens to the upper and lower surfaces. The opening of the duct port 160 on the upper surface side of the lower cover 78 is formed as a tapered surface 162 whose inner diameter increases toward the upper side. That is, when the cover housing 22 is sealed, the tapered surface 162 is inclined toward the inner wall surface of the upper cover 76. On the other hand, the L-shaped pipe 150 is connected to the opening of the duct port 160 on the lower surface side of the lower cover 78. The main pipe 154 is connected to the L-shaped pipe 150 via the connecting pipe 152. Note that the portion of the connecting pipe 152 on the L-shaped pipe 150 side is omitted. An ozone filter 166 is disposed inside the main pipe 154. The ozone filter 166 is made of activated carbon and adsorbs ozone.

[0041] 11, the control device 38 includes a controller 170 and a plurality of drive circuits 172. The plurality of drive circuits 172 are connected to the electrode 56, the process gas supply device 74, the electromagnetic motor 117, and the purge gas supply device 132. The controller 170 includes a CPU, a ROM, a RAM, and the like, and is mainly a computer, and is connected to the plurality of drive circuits 172. As a result, the operation of the plasma generation device 20, the lifting device 28, and the purge gas supply mechanism 32 is controlled by the controller 170. The controller 170 is also connected to the detection sensor 144. As a result, the controller 170 obtains the detection result of the detection sensor 144, that is, the oxygen concentration inside the cover housing 22.

[0042] By irradiating the culture solution with plasma, the culture solution is activated, and plasma is expected to be utilized in the medical field, such as cancer treatment using the plasma-irradiated culture solution. For this reason, the culture solution is generated by plasma irradiation, and it is preferable that the culture solution is irradiated with plasma under controlled conditions. In the atmospheric pressure plasma irradiation device 10, the irradiation block 180 is placed on the stage 26 and the cover housing 22 is sealed with the above-mentioned configuration, so that the culture solution can be irradiated with plasma under predetermined conditions. The method of irradiating the culture solution with plasma under predetermined conditions will be described in detail below.

[0043] Specifically, first, the irradiation block 180 is placed on the stage 26. Next, the lifting device 28 raises and lowers the stage 26 to a desired height. This makes it possible to set a desired distance between the plasma nozzle 72 and the culture solution as an object to be irradiated with the plasma. The height to which the stage 26 is raised and lowered can be confirmed by the scale on the measuring rod 118.

[0044] Next, the upper cover 76 is lowered to seal the cover housing 22. Then, the purge gas supply mechanism 32 supplies an inert gas to the inside of the cover housing 22. At this time, the concentration detection mechanism 34 detects the oxygen concentration in the cover housing 22. Then, after the detected oxygen concentration becomes equal to or lower than a preset threshold value, the plasma generator 20 ejects plasma into the inside of the cover housing 22. Note that the supply of the inert gas to the inside of the cover housing 22 continues even when the plasma is being irradiated. Also, the liquid to be treated, which has been adjusted to a constant flow rate, is flowed through the liquid feed tube 120 to the storage section 184 of the irradiation block 180. When a predetermined amount of the liquid to be treated is stored in the storage section 184, the liquid feed to the storage section 184 is stopped. Here, the predetermined amount is an amount in which the liquid to be treated does not overflow from the storage section 184 and the liquid level is equal to or higher than the height of the first bar-shaped member 187. Note that this situation is similar when the second bar-shaped member 188 is employed. The liquid to be treated stored in the storage section 184 is activated by being irradiated with plasma gas from the plasma generating device 20. It is known that the therapeutic effect of the plasma-irradiated liquid to be treated is exerted by irradiating the liquid to be treated with plasma gas for a predetermined period of time. The liquid to be treated is irradiated with plasma gas for a predetermined period of time by storing the liquid to be treated in the storage section 184. Furthermore, the liquid to be treated undergoes natural convection within the storage section 184 by being irradiated with plasma gas. This makes it possible to produce a homogeneous activated liquid to be treated that exerts a therapeutic effect.

[0045] In this way, by supplying an inert gas to the inside of the cover housing 22, the air in the cover housing 22 is exhausted to the outside of the cover housing 22. At this time, the oxygen concentration in the cover housing 22 is adjusted to manage the conditions that affect the plasma irradiation. In detail, since plasma contains active radicals, when it reacts with oxygen, it becomes ozone, and the effect of the plasma irradiation decreases. Therefore, by adjusting the oxygen concentration in the cover housing 22, it is possible to examine the effect of the oxygen concentration on the effect of the culture solution irradiated with plasma. In addition, it is possible to irradiate the culture solution with plasma under the same conditions. This makes it possible to efficiently generate a plasma-treated liquid.

[0046] As described above, the distance between the plasma nozzle 72 and the culture solution can be set arbitrarily in the atmospheric plasma irradiation device 10. This makes it possible to examine the influence of the irradiation distance on the effect of the culture solution irradiated with plasma, and makes it possible to efficiently produce a plasma-treated liquid.

[0047] Further, a duct opening 160 is formed in the lower cover 78. Therefore, by supplying an inert gas into the cover housing 22, the inside of the cover housing 22 becomes positive pressure, and the gas is naturally exhausted from the inside of the cover housing 22. Further, a tapered surface 162 is formed in the duct opening 160 of the lower cover 78, the inner diameter of which increases toward the upper surface of the lower cover 78. This makes it possible to promote the exhaust of gas from inside the cover housing 22. Furthermore, an ozone filter 166 is provided in the exhaust mechanism 36. This makes it possible to prevent the exhaust of ozone to the outside, even if the plasma reacts with oxygen and ozone is generated.

[0048] When a predetermined time has elapsed since the start of plasma irradiation, the plasma-treated liquid stored in the storage section 184 is discharged via the drainage tube 122. When a predetermined time has elapsed since the start of discharge of the plasma-treated liquid from the storage section 184, it is determined that no plasma-treated liquid remains in the storage section 184, and discharge of the plasma-treated liquid from the storage section 184 is completed. Then, the liquid to be treated that will be plasma-treated next is flowed via the liquid feed tube 120 to the storage section 184 of the irradiation block 180. Thereafter, the plasma treatment steps of irradiating the liquid to be treated stored in the storage section 184 with plasma for a predetermined time, draining the plasma-treated liquid, supplying new liquid to be treated to the irradiation block 180, irradiating the liquid to be treated with plasma, and so on are repeatedly performed until a predetermined amount of plasma-treated liquid is produced.

[0049] As described above, the atmospheric pressure plasma irradiation device 10 of this embodiment includes a storage section 184 that stores the liquid to be treated and has a drainage hole 184c on a bottom surface 184b for draining the stored liquid to be treated, a plasma generating device 20 that generates plasma to be irradiated onto the liquid to be treated stored in the storage section 184, and a first or second bar-shaped member 187, 188 that is erected on the bottom surface 184b of the storage section 184 and guides the liquid to be treated stored in the storage section 184 to the drainage hole 184c.

[0050] In this manner, in the atmospheric pressure plasma irradiation device 10 of the present embodiment, the liquid to be treated that is repelled at the entrance of the drainage hole 184c or that is attracted to the corner of the bottom surface 184b and remains on the bottom surface 184b is led to the drainage hole 184c along the first or second bar-shaped member 187, 188 and drained, so that the liquid to be treated stored in the storage portion 184 can be quickly discharged from the storage portion 184 without remaining in the storage portion 184. This further shortens the time for one step of the plasma treatment step for the liquid to be treated. This is because the above-mentioned predetermined time during which it is considered that no plasma treatment liquid remains in the storage portion 184 is shortened.

[0051] Incidentally, in this embodiment, the atmospheric plasma irradiation device 10 is an example of a "plasma irradiation device." The storage unit 184 is an example of a "storage container." The first and second bar-shaped members 187 and 188 are an example of a "drainage promoter."

[0052] In addition, bottom surface 184b of reservoir 184 slopes downward from its outer edge toward drainage hole 184c, making it possible to further shorten the time required for one step of the plasma treatment step for the liquid to be treated.

[0053] The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present disclosure.

[0054] (1) In the above embodiment, a culture solution is used as the object to be treated, but a liquid other than a culture solution can be used as the object to be treated. In addition, the present disclosure can be applied not only to the medical field but also to various fields such as the industrial field.

[0055] (2) In the above embodiment, the first bar-shaped member 187 has a length and a position corresponding to the diameter of the circular bottom surface 184b, but it does not have to be exactly aligned with the length and position corresponding to the diameter. For example, it may be aligned with the length and position corresponding to the chord close to the drainage hole 184c. In the above embodiment, both ends of the first bar-shaped member 187 are in contact with the side surface 184a, but a gap may be provided between the side surface 184a. Furthermore, the center of the first bar-shaped member 187 may be bent or cut out so that the entire drainage hole 184c can be seen when the operator looks at the top surface of the first bar-shaped member 187 from above in the Z direction. In the present embodiment, the second bar-shaped member 188 has a length and a position corresponding to the radius of the circular bottom surface 184b, but it does not have to be exactly aligned with the length and position corresponding to the radius.

[0056] (3) In the above embodiment, the first bar-shaped member 187 is placed at a position perpendicular to the direction in which the liquid to be treated flows into the storage portion 184, but it may be placed at any angle. The same applies to the second bar-shaped member 188.

[0057] (4) In the above embodiment, there is no mention of the fact that the amount of the treated liquid stored in the storage portion 184 is reduced by placing the first and second bar-shaped members 187, 188 on the storage portion 184. However, the size of the storage portion 184 may be increased by the amount of the reduction. [Explanation of symbols]

[0058] 10...atmospheric pressure plasma irradiation device, 20...plasma generation device, 38...control device, 72...nozzle, 132...purge gas supply device, 180...irradiation block, 184...storage section, 184a...side surface, 184b...bottom surface, 184c...drainage hole, 186...discharge section, 187...first bar-shaped member, 188...second bar-shaped member.

Claims

1. a storage container for storing the liquid to be treated and having a drainage hole on a bottom surface for draining the stored liquid to be treated; a plasma generating device that generates plasma to be irradiated onto the liquid to be treated stored in the storage container; a bar-shaped drainage promotion part that is provided on the bottom surface of the storage container and guides the liquid to be treated stored in the storage container to the drainage hole; A plasma irradiation device equipped with the device.

2. The bottom surface of the storage container slopes downward from its outer edge toward the drainage hole. The plasma irradiation device according to claim 1 .

3. The bottom surface of the storage container is circular, The drain hole is provided at approximately the center of the circular bottom surface, The plasma irradiation device according to claim 2 , wherein the drainage promotion portion is provided at a position and with a length substantially equivalent to a diameter of the circular bottom surface.

4. The bottom surface of the storage container is circular, The drain hole is provided at approximately the center of the circular bottom surface, The plasma irradiation device according to claim 2 , wherein the drainage promotion portion is provided at a position and with a length substantially corresponding to a radius of the circular bottom surface.

5. The drainage promotion unit is formed separately from the storage container and is placed on the bottom surface of the storage container to stand upright. The plasma irradiation device according to any one of claims 1 to 4.

6. The drainage promotion portion is integrally formed with the storage container. The plasma irradiation device according to any one of claims 1 to 4.

7. A method for producing a plasma-treated liquid, comprising: a storage container for storing the liquid to be treated and having a drainage hole on the bottom surface for draining the stored liquid to be treated; a plasma generating device for generating plasma to be irradiated to the liquid to be treated stored in the storage container; and a bar-shaped drainage promotion part erected on the bottom surface of the storage container and for directing the liquid to be treated stored in the storage container to the drainage hole, thereby producing a plasma-treated liquid by irradiating the liquid to be treated stored in the storage container with plasma.

8. When irradiating the liquid to be treated stored in the storage container with plasma, the plasma is irradiated in a state where the liquid level is higher than the height of the bar-shaped drainage promotion portion. The method for producing a plasma-treated liquid according to claim 7.

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