Ultra fine bubble production device

Abstract

This ultra fine bubble production device comprises: a storage unit in which a storage space in which a liquid and a gas are stored is formed inside; a pressurization unit which compresses the storage space to generate, in the storage space, a pressurized gas solution in which the gas is pressurized and dissolved in the liquid; a holding unit which holds a pressurized dissolution state in which the gas is pressurized and dissolved in the liquid; and a decompression unit which reduces the pressure of the pressurized gas solution by opening a communication passage for communicating the inside and the outside of the storage space in the pressurized dissolution state, and generate ultra fine bubbles.

Description

Ultra-fine bubble manufacturing equipment

[0001] The present invention relates to an apparatus for producing ultra-fine bubbles.

[0002] In recent years, technologies that utilize the properties of fine bubbles have been attracting attention. Bubbles with a diameter of less than 100 μm are called fine bubbles, and in particular, bubbles with a diameter of less than 1 μm (nano-sized) are called ultrafine bubbles and are distinguished from other bubbles. Their usefulness has been confirmed in a variety of fields.

[0003] Various methods for producing ultrafine bubbles have been developed. For example, a widely used method is a pressure dissolution method in which a gas is dissolved in a liquid under pressure, and then the pressure is suddenly reduced to create a supersaturated state, causing the gas to precipitate as ultrafine bubbles. One proposed pressure dissolution method for producing ultrafine bubbles includes a storage section for storing a liquid and a gas, and a drive section for pressurizing the interior of the storage section, and the time from the start of pressurization until the pressure reaches a maximum pressure is 2.0 milliseconds or less, and the maximum pressure is 4.00 MPa or more (see, for example, Patent Document 1).

[0004] International Publication No. 2021 / 090833

[0005] The technology of the present disclosure aims to provide a technology for improving the performance of an ultra-fine bubble manufacturing device.

[0006] In order to solve the above problems, the ultrafine bubble manufacturing apparatus according to the present disclosure employs the following configuration. That is, the gist of the technology according to the present disclosure is as follows: [1] An ultrafine bubble manufacturing apparatus comprising: a storage section having a storage space formed therein for storing a liquid and a gas; a pressurizing section that compresses the storage space to produce a pressurized gas solution in the storage space by pressurizing and dissolving the gas in the liquid; a holding section that maintains the pressurized and dissolved state of the gas in the liquid; and a decompression section that, in the pressurized and dissolved state, reduces the pressure of the pressurized gas solution by opening a communication passage that connects the inside and outside of the storage space to generate ultrafine bubbles. [2] The apparatus for producing ultrafine bubbles according to [1], wherein the pressurizing unit has a sliding part that is inserted into the storage unit so as to form the storage space between itself and the storage unit and is slidable within the storage unit along the insertion direction relative to the storage unit, the storage space being compressed when the sliding part moves relative to the storage unit in the insertion direction, and the holding part restricts the sliding part from moving relative to the storage unit in the opposite direction to the insertion direction in the pressurized dissolved state. [3] The apparatus for producing ultrafine bubbles according to [2], wherein the pressurizing unit is a threaded shank portion extending along the insertion direction and having a male thread groove formed on its outer periphery, the holding part is a threaded hole portion into which the threaded shank portion is inserted and has a female thread groove formed to threadably mate with the male thread groove of the threaded shank portion, and the threaded shank portion threads forward and backward relative to the threaded hole portion, causing the sliding part to move relative to the storage unit in the insertion direction. [4] The ultrafine bubble producing device according to any one of [1] to [3], wherein the pressure reducing unit has a valve element that can change its state from a closed state that blocks the communication passage to an open state that opens the communication passage, and a drive unit that imparts energy to the valve element to change the valve element from the closed state to the open state.[5] The device for producing ultra-fine bubbles according to [4], wherein the valve element fits into the communicating passage in the closed state to close the communicating passage, and the drive unit changes the valve element from the closed state to the open state by pushing the valve element from the outside to the inside of the accommodation space. [6] The device for producing ultra-fine bubbles according to [4] or [5], wherein the drive unit has an igniter that burns an ignition charge when supplied with operating power, and imparts combustion energy of the ignition charge to the valve element. [7] The device for producing ultra-fine bubbles according to [4] or [5], wherein the drive unit has an elastic body that imparts elastic energy to the valve element by restoring it from a compressed state to an elongated state that is more elongated than the compressed state.

[0007] According to the present disclosure, the performance of an ultrafine bubble manufacturing device can be improved.

[0008] FIG. 1 is an overall perspective view of an ultrafine bubble production apparatus (hereinafter simply referred to as "production apparatus") according to embodiment 1. FIG. 2 is a top view of the production apparatus according to embodiment 1. FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2. FIG. 4 is a partial cross-sectional view of the production apparatus according to embodiment 1, when the valve is closed and the storage space is in a gas-liquid separated state. FIG. 5 is a cross-sectional view taken along line B-B of FIG. 4. FIG. 6 is a cross-sectional view of the production apparatus according to embodiment 1, when the valve is closed and the storage space is in a pressurized dissolution state. FIG. 7 is a cross-sectional view of the production apparatus according to embodiment 1, when the storage space is in a pressurized dissolution state and the valve is open. FIG. 8 is a partial cross-sectional view of the production apparatus according to embodiment 1, when the storage space is in a pressurized dissolution state and the valve is open. FIG. 9 is a cross-sectional view of the production apparatus according to embodiment 2, when the valve is closed and the storage space is in a gas-liquid separated state. FIG. 10 is a cross-sectional view of the production apparatus according to embodiment 2, when the storage space is in a pressurized dissolution state and the valve is open.

[0009] Hereinafter, embodiments of the present disclosure will be described. Note that each configuration and combination thereof in the embodiments are merely examples, and addition, omission, substitution, and other modifications of the configuration are possible as appropriate within the scope of the gist of the present disclosure. The present disclosure is not limited by the embodiments, but is limited only by the claims.

[0010] One embodiment of the present disclosure is an apparatus for producing ultrafine bubbles, comprising: a storage section having a storage space formed therein for storing a liquid and a gas; a pressurizing section that compresses the storage space to produce a pressurized gas solution in the storage space in which the gas is pressurized and dissolved in the liquid; a holding section that maintains the pressurized dissolved state in which the gas is pressurized and dissolved in the liquid; and a decompression section that, in the pressurized dissolved state, decompresses the pressurized gas solution by opening a communication passage that connects the inside and outside of the storage space to generate ultrafine bubbles.

[0011] In this disclosure, "ultrafine bubbles" refers to bubbles with a diameter of less than 1 μm. Although the majority of bubbles produced by the device according to this embodiment are ultrafine bubbles, the bubbles produced by the device according to this embodiment may contain ultrafine bubbles, and may also contain bubbles that do not meet the above definition.

[0012] In the present disclosure, the liquid contained in the container is not particularly limited. Examples of the liquid include liquids that can be used as solvents (e.g., water, alcohol, oil, etc.). Examples of the liquid include solutions (e.g., culture medium (liquid culture medium), physiological saline, phosphate buffer solution, prepared reagents, solution-type cosmetics, etc.). Examples of the liquid include emulsions (e.g., emulsion-type cosmetics such as emulsions). A liquid containing two or more of these may also be used. Furthermore, the liquid may contain low-molecular-weight or high-molecular-weight substances, and may contain inorganic or organic substances (e.g., biological components such as nucleic acids). In a preferred aspect of this embodiment, the liquid does not contain microorganisms or the like. In a preferred aspect of this embodiment, the water is pure water (e.g., distilled water, RO water, RO-EDI water, ion-exchanged water), and in another preferred aspect, it is ultrapure water. Examples of ultrapure water include Milli-Q water.

[0013] In addition, in the present disclosure, the gas contained in the container is not particularly limited. Examples of the gas include air. Examples of the gas include nitrogen, oxygen, ozone, carbon dioxide, hydrogen, and carbon monoxide, and a mixture of two or more of these gases is also exemplified. In a preferred aspect of this embodiment, the gas is a gas that does not contain microorganisms, etc. The air may be any commonly used air, and its composition is not particularly limited. For example, a mixture of approximately 80% nitrogen and approximately 20% oxygen may be used.

[0014] In the present disclosure, the energy applied by the actuator to change the valve element to an open state that opens the communication passage can be applied using a known pressurization technique. One example of the applied energy may be chemically generated energy, such as combustion energy generated by an oxidation reaction of gunpowder, explosives, or the like. Alternatively, the energy for this change may be generated electrically, such as energy generated by a piezoelectric element or an electromagnetic actuator driven by input power. Alternatively, the energy for this change may be physically generated, such as elastic energy generated by an elastic body or internal energy possessed by a compressed object such as compressed gas. For example, the actuator may generate energy by releasing the pressure of compressed gas. Alternatively, the energy for this change may be generated manually (by human power). For example, the actuator may apply energy to the valve element by transmitting human power from an operator. That is, the energy for this change may be any energy that can change the valve element from a closed state to an open state. Furthermore, the energy for the change may be a composite energy that is an appropriate combination of combustion energy, electric energy, internal energy such as elastic energy, and manual (human power) energy.

[0015] <First Embodiment> Hereinafter, an apparatus for producing ultra-fine bubbles according to a first embodiment will be described with reference to the drawings.

[0016] [Overall Configuration] Figure 1 is an overall perspective view of an ultra-fine bubble manufacturing apparatus (hereinafter also simply referred to as "manufacturing apparatus") 100 according to embodiment 1. Figure 2 is a top view of the manufacturing apparatus 100 according to embodiment 1. Figure 3 is a cross-sectional view taken along the line A-A in Figure 2. The arrows shown in Figures 1 to 3 indicate the front-rear, up-down, and left-right directions of the manufacturing apparatus 100. Figure 3 shows a cross section along the front-rear direction of the manufacturing apparatus 100. In this specification, the operating screw side indicated by reference numeral 4 is the rear side, and the drive unit side indicated by reference numeral 7 is the front side, in the front-rear direction. However, the front-rear, up-down, left-right, and other directions in this specification merely indicate the relative positional relationships of the components that make up the manufacturing apparatus 100.

[0017] As shown in Fig. 1, the manufacturing apparatus 100 includes a container 1 (an example of a "storage unit" according to the present disclosure), a pressurizing unit 10, a decompression unit 20, and a holder 8 (an example of a "holding unit" according to the present disclosure). As shown in Fig. 3, a storage space S1 is formed inside the container 1 to store a liquid L1 and a gas G1. Figs. 1 to 3 illustrate a state in which the liquid L1 and the gas G1 in the storage space S1 are separated (hereinafter also referred to as a gas-liquid separated state), and a state in which the valve indicated by reference numeral 5 in Fig. 3 closes a communication passage indicated by reference numeral 14 (hereinafter also referred to as a closed state). Although details will be described later, the manufacturing apparatus 100 produces a pressurized gas-dissolved liquid L2 in which a gas G1 is pressurized and dissolved in a liquid L1 by compressing the storage space S1 using the pressurizing unit 10 (see FIG. 6), and then produces an ultra-fine bubble liquid L3 containing ultra-fine bubbles by rapidly depressurizing the pressurized gas-dissolved liquid L2 using the depressurizing unit 20 in the state in which the gas G1 is pressurized and dissolved in the liquid L1 (hereinafter referred to as the pressurized dissolved state) (see FIG. 7). Each component of the manufacturing apparatus 100 will be described below.

[0018] [Container] The container 1 is a cylindrical member with a bottom that extends in the front-rear direction and has one end (front end) closed and the other end (rear end) open. More specifically, the container 1 is formed in a syringe shape having a cylindrical peripheral wall portion 11 extending in the front-rear direction and a closing portion 12 that closes the front end of the peripheral wall portion 11, and the rear end of the peripheral wall portion 11 is open. However, the shape of the container 1 is not limited to a syringe shape. Also, in this example, the peripheral wall portion 11 is cylindrical, but is not limited to a cylindrical shape and may be, for example, a rectangular cylindrical shape. The peripheral wall portion 11 and the closing portion 12 form a sliding hole 13 in the container 1 that extends in the front-rear direction. The sliding hole 13 is formed as a space surrounded by the peripheral wall portion 11 and the closing portion 12, and opens at the rear end of the container 1 with the closing portion 12 as its bottom. That is, one end (front end) of the sliding hole 13 is closed by the closing portion 12, and the other end (rear end) is open. As will be described later, a storage space S1 is formed inside the container 1 by a portion of the sliding hole 13. Furthermore, a communication passage 14 is formed in the closing portion 12. The communication passage 14 is formed as a through-hole that penetrates the closing portion 12 in the front-rear direction. As a result, the communication passage 14 communicates between the inside of the storage space S1 and the outside of the storage space S1. This communication passage 14 is formed in the center of the closing portion 12 in a cross section perpendicular to the front-rear direction. The material of the container 1 is not particularly limited, but examples include resin materials. Examples of resin materials that can be used to form the container 1 include known materials such as nylon 6-12, polyarylate, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, and liquid crystal polymers.

[0019] [Pressurizing Unit] The pressurizing unit 10 includes a plunger 2 (an example of a "sliding unit" according to the present disclosure), a slider 3, and an actuating screw 4 (an example of a "screw shaft" according to the present disclosure), which are integrally connected together. The pressurizing unit 10 is disposed at the rear of the container 1 and is held by a holder 8 so as to be movable in the front-rear direction.

[0020] [Plunger] The plunger 2 has a substantially cylindrical outer shape and is inserted into the sliding hole 13 formed at the rear end of the container 1 through its opening. Here, the direction in which the plunger 2 is inserted into the container 1 is referred to as the "insertion direction." In this example, the "insertion direction" is a direction parallel to the front-rear direction, from the open end (rear end) of the container 1 toward the closed end (front end) of the container 1 (i.e., the front side in the front-rear direction). The plunger 2 is inserted into the container 1 so as to fit into the peripheral wall portion 11 of the container 1. As a result, an accommodation space S1 is formed between the container 1 and the plunger 2. The accommodation space S1 is formed as a space in the sliding hole 13 that is closer to the insertion direction than the plunger 2. The plunger 2 is also slidable within the container 1 (inside the sliding hole 13) along the insertion direction. When the valve 5 is in a closed state, the plunger 2 moves in the insertion direction while sliding on the inner wall of the sliding hole 13 (the inner peripheral surface of the peripheral wall portion 11), thereby compressing the accommodation space S1.

[0021] The plunger 2 includes a plunger body 21, a plunger rod 22, and a packing 23. The plunger body 21 is a cylindrical member extending in the front-rear direction, with a closed front end and an open rear end, and is fitted into the peripheral wall 11 of the container 1. The material of the plunger body 21 is not particularly limited, but examples include resin materials such as PPS (polyphenylene sulfide), POM (polyacetal), and PA (polyamide). The plunger body 21 may also be formed from a metal material such as aluminum, an aluminum alloy (e.g., A6061), or titanium. The plunger rod 22 is a substantially cylindrical shaft extending in the front-rear direction and is fixed in a state where it is fitted into the plunger body 21. The plunger rod 22 may be formed from a metal material such as stainless steel or steel. However, the material of the plunger rod 22 is not limited to the above. The plunger body 21 and plunger rod 22 are integrally formed, for example, by insert molding the resin plunger body 21 into the plunger rod 22. An annular mounting groove is formed on the outer peripheral surface of the plunger body 21 and extends in the circumferential direction, and an annular packing 23 is mounted in the mounting groove. The packing 23 is a sealing member that presses against the inner wall of the sliding hole 13 (the inner peripheral surface of the peripheral wall portion 11) to seal the accommodation space S1 and form a fitted state between the plunger 2 and the sliding hole 13. For example, a rubber O-ring can be used as the packing 23.

[0022] As described above, the plunger 2 is inserted into the container 1 so as to form an accommodation space S1 between the plunger 2 and the container 1, and is slidable within the container 1 along the insertion direction.

[0023] [Slider] The slider 3 is a cylindrical member that extends in the front-rear direction and has an open front end and a closed rear end. The slider 3 is disposed behind the plunger 2 and transmits the axial force of the actuation screw 4 to the plunger 2. A slit 31 is formed in the upper surface of the slider 3, extending in the front-rear direction from the middle of the slider 3 to the front end. A guide groove 32 is formed in the lower surface of the slider 3, extending in the front-rear direction (i.e., the insertion direction) across the entire area of ​​the slider 3. A recess 33 is formed in the front end of the slider 3, into which the rear end of the plunger body 21 is fitted. A generally cylindrical fitting portion 34 that protrudes rearward is formed in the rear end of the slider 3. The material of the slider 3 is not particularly limited, but examples thereof include the same resin material as that of the container 1 described above.

[0024] [Actuating Screw] The operating screw 4 is a threaded member having a male thread groove formed on the outer periphery of a shaft portion extending in the front-to-rear direction (insertion direction). The operating screw 4 according to this embodiment is formed as a headless threaded member also known as a threaded bolt or a full screw. As shown in FIG. 3 , a male thread groove 41 a is formed on the outer periphery 41 of the operating screw 4. The front end of the operating screw 4 is formed with a recessed insertion portion 43 that is recessed toward the rear and receives the insertion portion of the slider 3. The rear end of the operating screw 4 is formed with an engagement hole 44 for engaging a tightening tool with the operating screw 4. In this example, the engagement hole 44 is a square hole (a hole with a square cross-section) so that the tip of a square wrench serving as a tightening tool can be engaged therewith. However, the shape of the engagement hole 44 is not particularly limited and can be appropriately selected according to the shape of the tip of the tightening tool used to rotate the operating screw 4. For example, if a hexagonal wrench is used as the tightening tool, the engagement hole 44 may be a hexagonal hole (a hole with a hexagonal cross-sectional shape). The actuation screw 4 is inserted into a threaded hole 821 formed in the holder 8. Note that in this embodiment, the plunger 2 and the actuation screw 4 are formed as separate members, but in the technology according to the present disclosure, the sliding portion and the screw shaft portion may be formed as an integrated member. The material of the actuation screw 4 is not particularly limited, but examples include metal materials such as stainless steel and steel. The actuation screw 4 may also be formed from a resin material.

[0025] [Depressurization Section] The depressurization section 20 includes a valve 5 (an example of a “valve body” according to the present disclosure), a connecting member 6, and a drive section 7. The depressurization section 20 is disposed on the front side of the container 1 and is integrally connected to the container 1.

[0026] [Connecting Member] The connecting member 6 is a cylindrical member that extends in the front-rear direction and has open ends, and connects the container 1 and the drive unit 7. The connecting member 6 has a cylindrical large-diameter portion that includes the rear end of the connecting member 6 and a cylindrical small-diameter portion that includes the front end of the connecting member 6 and has an outer diameter smaller than that of the large-diameter portion. By connecting the rear end of the connecting member 6 to the front end (closure portion 12) of the container 1, a depressurization space S2 is formed between the container 1 and the large-diameter portion 61. In addition, a depressurization hole 63 that communicates the inside of the depressurization space S2 with the outside air is formed in the large-diameter portion 61. The material of the connecting member 6 is not particularly limited, but examples thereof include the same resin material as that of the container 1 described above.

[0027] [Valve] FIG. 4 is a partial cross-sectional view of the manufacturing apparatus 100 in the first embodiment when the valve 5 is closed and the storage space S1 is in a gas-liquid separation state. In FIG. 4, components other than the container 1, plunger 2, valve 5, and connecting member 6 are omitted. The valve 5 receives energy from the drive unit 7 and moves rearward in the front-to-rear direction, thereby changing its state from a closed state in which the communication passage 14 is blocked as shown in FIG. 4 to a state in which the communication passage 14 is opened as shown in FIG. 8 (hereinafter also referred to as an open state). In this specification, "open" refers to a state in which fluid can flow. When the storage space S1 is in a pressurized dissolution state, the valve 5 changes from a closed state to an open state, thereby reducing the pressure of the pressurized gas-dissolved liquid L2. Here, the movement direction of the valve 5 (rearward in the front-to-rear direction in this example) for switching the valve 5 from a closed state to an open state is referred to as the "open direction." In this example, the "opening direction" is a direction parallel to the front-to-rear direction from the closed end (front end) of the container 1 toward the open end (rear end) (i.e., the rear side in the front-to-rear direction). In this example, the "opening direction" and the "insertion direction" are opposite directions. The valve 5 includes a valve body 51 that opens and closes the communication passage 14, a valve rod 52 that receives energy from the drive unit 7, and a packing 5a that forms an interlocking state between the valve 5 and the communication passage 14 in the closed state.

[0028] The valve body 51 is formed in a generally cylindrical shape extending in the front-to-rear direction and includes a stopper portion 511 constituting the end (rear end) of the valve body 51 in the opening direction, and an insertion portion 512 extending from the stopper portion 511 toward the opposite side of the opening direction (front side). The stopper portion 511 has a diameter (width) larger than the opening width of the communication passage 14 on the storage space S1 side so as to prevent the valve 5 from passing through the communication passage 14. Therefore, in the closed state, the stopper portion 511 abuts against the closure portion 12 of the container 1 from the opening direction (rear side), thereby restricting movement of the valve 5 toward the opposite side of the opening direction (front side). As a result, in the closed state, the valve 5 is restricted from passing through the communication passage 14 toward the opposite side of the opening direction to open the communication passage 14. The stopper portion 511 also has a shape that narrows in width (diameter) toward the opening direction (rear side) so as to facilitate insertion into the pressurized gas solution L2. This makes it easier for the valve 5, which receives energy from the drive unit 7, to move in the opening direction, thereby facilitating switching of the valve 5 from the closed state to the open state. The insertion portion 512 extends forward from the stopper portion 511, is inserted into the communication passage 14, and is connected to the valve rod 52 within the depressurization space S2. An annular mounting groove 513 is formed on the outer circumferential surface of the insertion portion 512 and extends circumferentially. The material of the valve body 51 is not particularly limited, but examples include metal materials such as brass. The valve body 51 may also be formed from a resin material.

[0029] The valve rod 52 is formed in a cylindrical shape extending in the front-rear direction and is inserted into the small-diameter portion 62 of the connecting member 6. The valve rod 52 is positioned so that its end (rear end) in the opening direction is located within the depressurization space S2 and its end (front end) opposite the opening direction is located in the drive unit 7. An insertion hole 521 is formed in the rear end of the valve rod 52, into which the insertion portion 512 of the valve body 51 is inserted. The rear end of the valve rod 52 has a diameter (width) larger than the opening width of the communicating passage 14 on the depressurization space S2 side so as to prevent the valve rod 52 from passing through the communicating passage 14. Therefore, the valve rod 52 abuts against the closing portion 12 of the container 1 from the opposite side of the opening direction (front side), thereby restricting movement of the valve 5 in the opening direction (rear side). As a result, in the open state, the valve 5 is restricted from passing through the communicating passage 14 in the opening direction (see FIG. 8 ). The material of the valve rod 52 is not particularly limited, but examples thereof include the same resin material as that of the container 1 described above.

[0030] Here, Fig. 5 is a cross-sectional view taken along the line B-B in Fig. 4. Fig. 5 shows a cross section perpendicular to the opening direction (front-rear direction in this example) of the valve 5. As shown in Figs. 4 and 5, the valve rod 52 may be formed with a slit 522 that extends in the opening direction and opens to the rear end surface of the valve rod 52.

[0031] As shown in Figure 4, a packing 5a, which is an annular sealing member, is fitted into the mounting groove 513 of the valve body 51. The packing 5a presses against the inner wall of the communicating passage 14 to seal the accommodation space S1 and to establish a fitted state between the valve 5 and the communicating passage 14. For example, a rubber O-ring can be used as the packing 5a. When the valve 5 is in the closed state, it fits into the communicating passage 14, thereby closing the communicating passage 14.

[0032] In order to maintain the valve 5 in the closed state, a biasing member may be provided that biases the valve 5 in the direction opposite to the opening direction. For example, a compressed spring may be interposed as the biasing member between the valve rod 52 and the closing portion 12 of the container 1.

[0033] [Drive Unit] When the drive unit 7 is activated, it applies energy to the valve 5 to change it from a closed state to an open state. More specifically, the drive unit 7 applies combustion energy of an ignition charge to the valve 5, and pushes the valve 5 from the outside toward the inside of the accommodation space S1, thereby switching the valve 5 from the closed state to the open state. As shown in Fig. 3 , the drive unit 7 has a casing 71, an igniter 72, a fixing member 73, and a piston 74.

[0034] [Casing] The casing 71 is a cylindrical member extending in the front-rear direction. The small-diameter portion 62 of the connecting member 6 is fitted and coupled to the rear end of the casing 71. The igniter 72 is fitted and fixed to the front end of the casing 71 via a fixing member 73. The front end of the valve rod 52, which protrudes forward from the small-diameter portion 62 of the connecting member 6, is inserted into the casing 71. The outer diameter of the rear end of the casing 71 is smaller than the outer diameter of the large-diameter portion 61 of the connecting member 6. Therefore, the connecting member 6 protrudes radially outward beyond the rear end of the casing 71, forming a radial step 201 in the pressure reducing section 20 between the connecting member 6 and the drive unit 7. The material of the casing 71 is not particularly limited, but examples include metal materials such as stainless steel and steel. The casing 71 may also be formed from the same resin material as the container 1 described above.

[0035] [Igniter] The igniter 72 is configured as an electric igniter and serves as a drive source for the drive unit 7, generating energy for switching the valve 5 from a closed state to an open state. The igniter 72 has an igniter body 721 containing an ignition charge and a conductive pin 722 extending from the igniter body 721. The igniter 72 is activated by operating power supplied to the conductive pin 722 from an external power source (not shown), such as a battery, to combust the ignition charge, thereby releasing combustion products (such as flames and combustion gases). This generates combustion energy as the pressure of the combustion products. The igniter 72 is fitted into the front end of the casing 71 so that the igniter body 721 faces the interior space of the casing 71 and the conductive pin 722 faces the exterior space of the casing 71. The conductive pin 722 is configured to be connectable to a power supply connector (not shown), and by connecting the conductive pin 722 to the power supply connector, operating power can be supplied to the igniter 72.

[0036] [Ignition Charge] Examples of the ignition charge used in the igniter 72 include explosives containing zirconium and potassium perchlorate (ZPP), explosives containing titanium hydride and potassium perchlorate (THPP), explosives containing titanium and potassium perchlorate (TiPP), explosives containing aluminum and potassium perchlorate (APP), explosives containing aluminum and bismuth oxide (ABO), explosives containing aluminum and molybdenum oxide (AMO), explosives containing aluminum and copper oxide (ACO), explosives containing aluminum and iron oxide (AFO), and explosives consisting of a combination of these explosives. Note that other explosives may also be used as the ignition charge as long as they generate energy sufficient to switch the valve 5 from a closed state to an open state.

[0037] [Fixing Member] The fixing member 73 is formed by injection molding of resin. A known method can be used for the injection molding. The fixing member 73 can be made of the same resin material as the container 1. The fixing member 73 fixes the igniter 72 to the casing 71 so as to close the front end of the casing 71.

[0038] [Piston] The piston 74 is formed in a generally cylindrical shape extending in the front-rear direction and is disposed between the valve rod 52 and the igniter 72 in the internal space of the casing 71. The piston 74 is movable in the opening direction while sliding along the inner circumferential surface of the casing 71, and transmits combustion energy (pressure) generated by activation of the igniter 72 to the valve 5. The piston 74 may be formed from a metal material such as stainless steel or steel, and an O-ring or the like may be disposed in part of the piston 74 to enhance adhesion with the sliding surface on which the piston 74 slides (i.e., the inner circumferential surface of the casing 71). Alternatively, the piston 74 may be made of resin, in which case metal may be used in combination in portions requiring heat resistance and pressure resistance. However, the material of the piston 74 is not particularly limited.

[0039] As shown in FIG. 3 , a combustion chamber S3 is formed in the internal space of the casing 71 between the igniter 72 and the piston 74. The combustion chamber S3 generates gas by combustion upon contact with the combustion product of the ignition charge, in order to increase the energy imparted to the valve 5. In other words, the combustion energy of the gas generant may be imparted to the valve 5 in addition to the combustion energy of the ignition charge. An example of the gas generant is a single-base smokeless powder (GG) composed of 98% by mass of nitrocellulose, 0.8% by mass of diphenylamine, and 1.2% by mass of potassium sulfate. It is also possible to use various gas generants used in gas generators for airbags and gas generators for seatbelt pretensioners.

[0040] [Holder] The holder 8 is configured to maintain a pressurized dissolved state. The material of the holder 8 is not particularly limited, but examples include metal materials such as stainless steel and steel. The holder 8 may also be formed from the same resin material as the container 1 described above. As shown in FIGS. 1 to 3 , the holder 8 has a base portion 81, a first support portion 82, a guide portion 83, and a second support portion 84.

[0041] The base portion 81 is formed in the shape of a plate that is perpendicular to the up-down direction and extends in the front-rear direction. The container 1, the pressurizing unit 10, and the decompressing unit 20 are placed on the base portion 81. A first support portion 82, a guide portion 83, and a second support portion 84 are provided on the upper surface of the base portion 81.

[0042] The first support portion 82 is a portion that supports the actuation screw 4 of the pressure applying unit 10 and is erected so as to extend in the left-right direction along the rear end edge of the base portion 81. A threaded hole 821 (an example of a "threaded hole portion" according to the present disclosure) into which the actuation screw 4 is inserted is formed in the first support portion 82. The threaded hole 821 extends in the front-rear direction and penetrates the first support portion 82. As shown in FIG. 3 , a female thread groove 82a is formed on the inner circumferential surface of the threaded hole 821 and threads into the male thread groove 41a formed on the outer circumferential surface 41 of the actuation screw 4. The male thread groove 41a of the actuation screw 4 threads into the female thread groove 82a of the threaded hole 821, so that the actuation screw 4 is supported by the first support portion 82. The actuation screw 4 can be moved in the front-rear direction by rotating the actuation screw 4 about its axis relative to the threaded hole 821. On the other hand, the engagement between the male screw groove 41a and the female screw groove 82a restricts the movement of the operating screw 4 in the forward and backward directions without any rotational operation.

[0043] The guide portion 83 is a portion that guides the movement of the slider 3 of the pressure unit 10 in the front-rear direction, and is erected at a position forward of the first support portion 82. The guide portion 83 has a pair of guide walls 831, 831 erected to extend in the front-rear direction along the left and right edges of the base portion 81, and a guide rib 832 that is provided between the pair of guide walls 831, 831 in the left-right direction and erected to extend in the front-rear direction. The pair of guide walls 831, 831 are adjacent to both the left and right sides of the slider 3, and the guide rib 832 is received in a guide groove 32 formed on the underside of the slider 3. In this way, the movement of the slider 3 in the front-rear direction is guided by the guide portion 83.

[0044] The second support portion 84 is a portion that supports the pressure reduction portion 20, and is erected at a position forward of the guide portion 83. The second support portion 84 has a receiving portion 841 that is a recess that receives the pressure reduction portion 20 and opens upward. The inner wall of the receiving portion 841 has an abutment portion 842 that abuts against the step portion 201 formed in the pressure reduction portion 20 from the front side (the leading end in the insertion direction). As a result, the pressure reduction portion 20 is supported by the second support portion 84 so that movement in the insertion direction is restricted. As described above, since the pressure reduction portion 20 and the container 1 are integrally connected, movement of the container 1 in the insertion direction is also restricted by the second support portion 84.

[0045] [Operation] The operation of the manufacturing apparatus 100 will be described below. Fig. 6 is a cross-sectional view of the manufacturing apparatus 100 in the first embodiment when the storage space S1 is in a pressurized dissolution state with the valve 5 closed. Fig. 7 is a cross-sectional view of the manufacturing apparatus 100 in the first embodiment when the storage space S1 is in a pressurized dissolution state with the valve 5 open. Figs. 6 and 7 correspond to the cross-sectional view of Fig. 3 and illustrate a cross section along the front-rear direction of the manufacturing apparatus 100. Fig. 8 is a partial cross-sectional view of the manufacturing apparatus 100 in the first embodiment when the storage space S1 is in a pressurized dissolution state with the valve 5 open. Fig. 8 corresponds to Fig. 4 and does not illustrate anything other than the container 1, plunger 2, valve 5, and connecting member 6.

[0046] 3, the container 1, the pressurizing unit 10, and the decompression unit 20 are attached to the holder 8 with the desired liquid L1 and gas G1 contained in the storage space S1. At this time, the valve 5 is closed to block the communication path 14 and seal the storage space S1 so that the liquid L1 and the gas G1 do not flow into the depressurization space S2 via the communication path 14. At this stage, the storage space S1 is not compressed to the extent that the gas G1 is pressurized and dissolved in the liquid L1, and is in a gas-liquid separated state.

[0047] Next, as shown in Figure 6, the pressure unit 10 compresses the storage space S1, thereby pressurizing and dissolving the gas G1 in the liquid L1, creating a pressurized, dissolved state (pressurization step). Specifically, with the valve 5 closed, the actuation screw 4 is rotated to advance the actuation screw 4 in the insertion direction (forward in the front-to-rear direction). The actuation screw 4 may be rotated by a user's bare hands, or by a tightening tool using an engagement hole 44 formed at the rear end of the actuation screw 4. Alternatively, a motor may be connected to the actuation screw 4 to electrically rotate the actuation screw 4.

[0048] As described above, the plunger 2, the slider 3, and the actuation screw 4 are integrally connected, and therefore the slider 3 and plunger 2 also move in the insertion direction in conjunction with the actuation screw 4. Specifically, as the actuation screw 4 threadably advances along the threaded hole 821 in the insertion direction, the slider 3 connected to the actuation screw 4 is pushed in the insertion direction by the axial force of the actuation screw 4 and moves in the insertion direction while being guided by the guide portion 83. Similarly, the plunger 2 connected to the slider 3 is pushed in the insertion direction by the axial force of the actuation screw 4 transmitted via the slider 3. Here, as described above, the movement of the container 1 in the insertion direction is restricted by the second support portion 84 of the holder 8. Therefore, the plunger 2 inserted into the container 1 slides in the insertion direction within the slide hole 13 of the container 1. The relative movement of the plunger 2 in the insertion direction with respect to the container 1 reduces the volume of the storage space S1. At this time, because the valve 5 is closed and the storage space S1 is sealed, the storage space S1 is compressed, and the liquid L1 and the gas G1 are pressurized. The liquid L1 and the gas G1 are gradually pressurized as the actuation screw 4 is threaded in the insertion direction. In the pressurized dissolution state, the compression of the storage space S1 by the pressurizing unit 10 presses the valve 5 in the opposite direction to the opening direction (front side). However, as described above, the stopper portion 511 restricts the valve 5 from moving forward, and therefore the valve 5 is restricted from passing forward through the communication passage 14 and opening the communication passage 14. This maintains the valve 5 in the closed state.

[0049] As the gas G1 is pressurized, the gas G1 dissolves in the liquid L1, resulting in a supersaturated state, generating a pressurized gas-dissolved liquid L2 in the storage space S1. The pressurized gas-dissolved liquid L2 is a liquid in which the gas G1 is pressurized and dissolved in the liquid L1. This creates a pressurized, dissolved state within the storage space S1. In this pressurized, dissolved state, the restoring force (repulsion force) of the compressed storage space S1 presses the plunger 2 toward the opposite side of the insertion direction (rearward). However, the engagement between the male thread groove 41a of the actuation screw 4 and the female thread groove 82a of the holder 8 restricts the actuation screw 4 from moving rearward. Therefore, the plunger 2 is prevented from moving relative to the container 1 toward the opposite side of the insertion direction. This maintains the compressed state of the storage space S1 by the holder 8, maintaining the pressurized, dissolved state within the storage space S1.

[0050] Next, as shown in Figures 7 and 8, in the pressurized dissolution state, the valve 5 of the pressure reduction section 20 is changed from a closed state to an open state, thereby rapidly reducing the pressure of the pressurized gas solution L2 (pressure reduction process), thereby generating an ultra-fine bubble liquid L3.

[0051] In detail, the igniter 72 is activated by supplying operating power to the igniter 72 while the pressurized melted state is maintained by the holder 8. The supply of power to the igniter 72 may be controlled by a control unit (not shown) such as a microcomputer. For example, when a user operates a predetermined switch (not shown), the control unit uses this as a trigger to supply operating power from the power source to the conductive pin 772 of the igniter 72.

[0052] When the igniter 72 is activated, the ignition charge housed in the igniter body 721 burns, releasing combustion products of the ignition charge into the combustion chamber S3. As a result, the piston 74 is pressed in the opening direction (rearward) of the valve 5 by the combustion energy of the ignition charge (pressure of the combustion products). The piston 74 moves at high speed in the opening direction while sliding on the inner circumferential surface of the casing 71. When the piston 74 collides with the valve rod 52 of the valve 5, the combustion energy of the ignition charge is transmitted to the valve 5, pressing the valve 5 in the opening direction. When the valve 5 moves at high speed in the opening direction, the engagement between the valve body 51 and the communication passage 14 is released, and the valve 5 is instantly switched to the open state, and the communication passage 14 is opened.

[0053] Here, as a result of the valve 5 being pressed in the opening direction, in the open state, the rear end face of the valve rod 52 abuts against the closing portion 12 of the container 1, restricting the valve 5 from passing through the communication passage 14 in the opening direction. At this time, the valve rod 52 has a slit 522 that opens into the rear end face of the valve rod 52, so that the opening of the communication passage 14 on the side of the depressurization space S2 is prevented from being blocked by the valve rod 52.

[0054] When the communicating passage 14 opens in the pressurized dissolution state, the storage space S1 is released from its airtight state. This releases the pressure in the storage space S1 to the depressurization space S2 via the communicating passage 14. More specifically, a portion of the pressurized gas solution L2 in the storage space S1 flows into the depressurization space S2 via the communicating passage 14. It is possible to release the pressure in the storage space S1 to the depressurization space S2 even if the valve rod 52 does not have a slit 522. Furthermore, the pressure is released to the outside air via the pressure relief hole 63 formed in the connecting member 6. This causes the pressurized gas solution L2 in the storage space S1 to be rapidly depressurized. This rapid depressurization of the pressurized gas solution L2 causes the gas G1 to precipitate in the liquid L1 as ultrafine bubbles. As a result, ultrafine bubble liquid L3 containing ultrafine bubbles is produced in the storage space S1. In this manner, ultrafine bubbles are produced by the manufacturing apparatus 100.

[0055] After the ultra-fine bubbles have been produced, for example, the container 1 and the pressure reducing section 20 may be removed from the holder 8 with the plunger 2 inserted in the container 1, and the plunger 2 may then be pulled out from the container 1, and the ultra-fine bubble liquid L3 contained in the container 1 may be collected in an appropriate container.

[0056] [Actions and Effects] As described above, the manufacturing apparatus 100 according to the first embodiment includes the container 1 having the storage space S1 formed therein for storing the liquid L1 and the gas G1, the pressurizing unit 10 for compressing the storage space S1 to generate a pressurized gas-dissolved liquid L2 in the storage space S1, in which the gas G1 is pressurized and dissolved in the liquid L1, the holder 8 for maintaining the pressurized dissolved state in which the gas G1 is pressurized and dissolved in the liquid L1, and the decompression unit 20 for decompressing the pressurized gas-dissolved liquid L2 and generating ultra-fine bubbles by opening the communication passage 14 that communicates the inside and outside of the storage space S1 (in this example, the depressurization space S2) in the pressurized dissolved state.

[0057] That is, the manufacturing apparatus 100 according to this embodiment includes a pressurizing unit 10 for forming a pressurized dissolved state by pressurization and a decompression unit 20 for decompressing the pressurized gas solution L2, and can maintain the pressurized dissolved state using the holder 8. With this manufacturing apparatus 100, after the pressurized dissolved state is formed by the pressurizing unit 10, the pressurized dissolved state can be temporarily maintained by the holder 8 before the pressurized gas solution L2 is decompressed by the decompression unit 20. This ensures that the gas G1 has time to disperse over a wide area in the liquid L1 in the pressurized dissolved state.

[0058] Generally, when fine bubbles are generated by the pressure dissolution method, the pressure-dissolved gas is dispersed over a wider area in the liquid, which expands the area in which fine bubbles can be generated in the subsequent decompression process, and therefore it is thought that the final fine bubble concentration will be higher.

[0059] In contrast, the manufacturing apparatus 100 of this embodiment can maintain the pressurized dissolved state using the holder 8, so that the pressurized gas solution L2 can be depressurized with the gas G1 dispersed over a wide area in the liquid L1, compared to when the pressurized gas solution L2 is depressurized immediately after the pressurized dissolved state is formed, thereby increasing the number of ultra-fine bubbles that can be generated.As a result, the manufacturing apparatus 100 of this embodiment can produce a high concentration of ultra-fine bubbles in the ultra-fine bubble solution L3.

[0060] The manufacturing apparatus 100 according to this embodiment was able to generate ultrafine bubbles at a concentration of 10 billion or more per milliliter. The number and particle size of the ultrafine bubbles were measured and analyzed using NanoSight (Spectris Inc.). However, the number of ultrafine bubbles described above does not limit the technology according to the present disclosure. Furthermore, since the ultrafine bubbles are generated in the airtight storage space S1 in this embodiment, the apparatus is suitable for generating ultrafine bubbles in a closed system, such as a sterile environment.

[0061] As described above, according to the first embodiment, the performance of the ultra-fine bubble producing apparatus 100 can be improved.

[0062] Furthermore, the manufacturing apparatus 100 according to this embodiment includes a pressurizing unit 10, which compresses the storage space S1 to form a pressurized dissolved state, and a decompression unit 20, which decompresses the pressurized gas solution L2 by opening the communication passage 14, as separate components. Therefore, compared to when pressurization and decompression are performed using a component in which the pressurizing means and decompression means are integrated, the driving force required for pressurization and decompression can be reduced. This makes it easier to increase the size of the pressurizing unit 10, for example, and the capacity of the storage space S1 can be increased accordingly. Furthermore, because the driving force required for pressurization and decompression can be reduced, the overall apparatus can be made smaller and costs can be reduced compared to when pressurization and decompression are performed using an integrated component with the same capacity of the storage space S1.

[0063] Furthermore, in this embodiment, the pressurizing unit 10 has a plunger 2 that is inserted into the container 1 so as to form a storage space S1 between itself and the container 1 and is slidable within the container 1 along the insertion direction relative to the container 1, and the storage space S1 is compressed when the plunger 2 moves relative to the container 1 in the insertion direction. The holder 8 restricts the plunger 2 from moving relative to the container 1 in the opposite direction to the insertion direction in the pressurized dissolution state. This allows the holder 8 to maintain the pressurized dissolution state.

[0064] In this embodiment, the pressurizing unit 10 has an actuation screw 4 that extends along the insertion direction and has a male screw groove 41a formed on its outer periphery. The holder 8 has a threaded hole 821 into which the actuation screw 4 is inserted. The threaded hole 821 has a female screw groove 82a that threadably engages with the male screw groove 41a of the actuation screw 4. As the actuation screw 4 threads along the threaded hole 821, the plunger 2 moves relative to the container 1 in the insertion direction. This prevents the plunger 2 from moving relative to the container 1 in the opposite direction of the insertion direction without rotating the actuation screw 4, due to the engagement between the male screw groove 41a and the female screw groove 82a. Furthermore, because the plunger 2 compresses the storage space S1 in conjunction with the threaded advancement of the actuation screw 4, rotating the actuation screw 4 at a slow speed allows the liquid L1 and the gas G1 to be gradually pressurized over time. This allows the gas G1 to be dispersed over a wide area in the liquid L1 in a pressurized, dissolved state, enabling the production of ultra-fine bubbles at a high concentration. In the technology according to the present disclosure, the means for restricting the relative movement of the sliding part in the opposite direction to the insertion direction with respect to the accommodating part is not limited to the use of threaded engagement between screw grooves. The holding part according to the present disclosure may also restrict the movement of the sliding part by, for example, a latch mechanism.

[0065] In this embodiment, the pressure reduction unit 20 includes a valve 5 that can change its state from a closed state that blocks the communicating passage 14 to an open state that opens the communicating passage 14, and a drive unit 7 that applies energy to the valve 5 to change the valve 5 from the closed state to the open state. That is, the manufacturing apparatus 100 according to this embodiment opens the communicating passage 14 by opening the valve 5 in the pressurized dissolution state, thereby reducing the pressure of the pressurized gas solution L2. Because the pressure is reduced by opening the valve 5, the pressure of the pressurized gas solution L2 can be rapidly reduced.

[0066] Furthermore, in general, when fine bubbles are generated by the pressure dissolution method, the speed at which pressure is reduced during pressure dissolution also affects the concentration of fine bubbles. If the pressure is reduced too slowly, bubbles may come into contact with each other and coalesce during the precipitation process, forming larger bubbles, which may reduce the number of ultrafine bubbles generated.

[0067] In contrast, the production apparatus 100 according to this embodiment can increase the decompression rate to prevent bubbles from becoming larger and increase the number of ultra-fine bubbles produced. As a result, the production apparatus 100 according to this embodiment can produce ultra-fine bubbles at a high concentration in the ultra-fine bubble liquid L3.

[0068] Furthermore, since a large driving force is not required to instantly switch the valve 5 to the open state, the pressurized gas solution L2 can be rapidly depressurized with a relatively small driving force. Note that the pressure reducing unit according to the present disclosure does not have to open the communication passage with a valve body. For example, instead of opening and closing a communication passage that is pre-formed in the storage unit with a valve body, the communication passage may be formed in the storage unit in an open state by operating the pressure reducing unit.

[0069] Furthermore, in this embodiment, the valve 5 fits into the communicating passage 14 in the closed state to block the communicating passage 14, and the drive unit 7 changes the valve 5 from the closed state to the open state by pushing the valve 5 from the outside toward the inside of the accommodation space S1. That is, the manufacturing apparatus 100 according to this embodiment switches the valve 5 to the open state by pushing the valve 5 to release it from engagement with the communicating passage 14. This makes it possible to instantly switch the valve 5 to the open state. Note that, in the technology according to the present disclosure, the method for changing the valve element from the closed state to the open state is not limited to the method described above. For example, the valve element may be rotated so as to cover the opening of the communicating passage in the closed state, thereby changing the valve element to the open state, which opens the communicating passage.

[0070] Furthermore, in this embodiment, the drive unit 7 has an igniter 72 that burns an ignition charge when supplied with operating power, and imparts the combustion energy of the ignition charge to the valve 5. This makes it possible to instantly switch the valve 5 to the open state because the combustion energy is used.

[0071] Furthermore, in this embodiment, the communication passage 14 is formed at the center of the closing portion 12 of the container 1. Therefore, when the communication passage 14 is opened, the pressure of the pressurized gas solution can be reduced over a wide range, thereby enabling the production of ultra-fine bubbles at a high concentration.

[0072] <Embodiment 2> The following describes a manufacturing apparatus 100A according to embodiment 2. In the description of embodiment 2, the description will focus on configurations that differ from the manufacturing apparatus 100 described with reference to Fig. 1 etc., and configurations that are similar to those of the manufacturing apparatus 100 will be assigned the same reference numerals as those of the manufacturing apparatus 100, and detailed description thereof will be omitted.

[0073] FIG. 9 is a cross-sectional view of the manufacturing apparatus 100A in the second embodiment when the valve 5 is closed and the storage space S1 is in a gas-liquid separation state. FIG. 10 is a cross-sectional view of the manufacturing apparatus 100A in the second embodiment when the storage space S1 is in a pressurized dissolution state and the valve 5 is open. FIGS. 9 and 10 correspond to the cross-sectional view of FIG. 3 and illustrate a cross section along the front-rear direction of the manufacturing apparatus 100A. As shown in FIGS. 9 and 10, the manufacturing apparatus 100A in the second embodiment differs from the manufacturing apparatus 100 in the first embodiment in that the drive unit 7A has a compression spring 76 (an example of an "elastic body" according to the present disclosure) instead of the igniter 72. The container 1, pressurizing unit 10, valve 5, connecting member 6, and holder 8 in the second embodiment are similar to those in the first embodiment, and therefore will not be described.

[0074] The driving unit 7A according to the second embodiment has a casing 71, a cover member 75, a compression spring 76, and a piston 77. The driving unit 7A applies elastic energy to the valve 5, which is released when the compression spring 76 returns from the compressed state shown in Fig. 9 to an extended state shown in Fig. 10 that is more extended than the compressed state.

[0075] The cover member 75 is connected to the front end of the casing 71 to close the front end. The cover member 75 also has a cylindrical elastic support portion 751 that protrudes rearward in the internal space of the casing 71.

[0076] The compression spring 76 is a so-called compression coil spring, and serves as a drive source for the drive unit 7A, generating energy for switching the valve 5 from a closed state to an open state. The compression spring 76 is attached to the elastic support portion 751 of the cover member 75 so that the direction of expansion and contraction of the compression spring 76 coincides with the opening direction of the valve 5. The compression spring 76 can be switched between a fixed compressed state in the front-rear direction as shown in FIG. 9 and a released compressed state by operating an operating unit (not shown) provided on the casing 71, for example. When the compressed state is released, the compression spring 76 expands due to its restoring force, and assumes the expanded state shown in FIG. 10.

[0077] The piston 77 is a cylindrical member with a bottom that extends in the front-to-rear direction and has an open front end and a closed rear end, and is attached to the rear end (the end on the opening direction side of the valve 5) of the compression spring 76. The piston 77 is movable in the opening direction while sliding on the inner circumferential surface of the casing 71, and transmits elastic energy that is released when the compression spring 76 returns from a compressed state to an extended state to the valve 5. The piston 77 can be made of a metal material such as stainless steel or steel. However, the material of the piston 77 is not particularly limited.

[0078] The operation of the manufacturing apparatus 100A will be described below. Note that the pressurizing step for forming the pressurized dissolved state is the same as that of the manufacturing apparatus 100 according to the first embodiment, and therefore the description thereof will be omitted. Here, the depressurizing step will be described.

[0079] Releasing the compression spring 76 in the pressurized dissolution state causes the spring 76 to return to an extended state, as shown in FIG. 10 . The spring 76 only needs to be longer in the extended state than in the compressed state, and need not be longer than its natural length. The elastic energy released when the spring 76 returns from the compressed state to the extended state causes the piston 77 to slide along the inner circumferential surface of the casing 71 at high speed in the opening direction (rearward) of the valve 5. When the piston 77 collides with the valve rod 52 of the valve 5, the elastic energy of the spring 76 is transmitted to the valve 5, pressing the valve 5 in the opening direction. As the valve 5 moves in the opening direction at high speed, the engagement between the valve body 51 and the communicating passage 14 is released. As a result, the valve 5 is instantly switched to the open state, and the communicating passage 14 is opened. This rapidly reduces the pressure of the pressurized gas solution L2 in the storage space S1, generating ultra-fine bubble solution L3 containing ultra-fine bubbles in the storage space S1. In this manner, ultrafine bubbles are produced by the production apparatus 100A.

[0080] As described above, in the manufacturing apparatus 100A according to the second embodiment, the drive unit 7A includes the compression spring 76, which applies elastic energy to the valve 5 by restoring the spring 76 from a compressed state to a state that is more elongated than the compressed state. This allows the valve 5 to be instantly switched to an open state using elastic energy. As a result, the pressure of the pressurized gas solution L2 can be rapidly reduced.

[0081] Alternatively, a drive unit separate from the manufacturing apparatus may be configured to be detachable from the manufacturing apparatus. The drive unit may include, for example, a compression spring that is arranged in parallel with the manufacturing apparatus and returns to an extended state by operating a trigger, and a hammer that receives elastic energy from the compression spring and rotates to strike the valve rod 52.

[0082] The above describes embodiments of the ultra-fine bubble manufacturing apparatus according to the present disclosure, but each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0083] DESCRIPTION OF SYMBOLS 1: Container (an example of a "storage section") 2: Plunger (an example of a "sliding section") 4: Actuating screw (an example of a "screw shaft section") 5: Valve (an example of a "valve body") 7, 7A: Driving section 8: Holder (an example of a "holding section") 10: Pressurizing section 20: Decompressing section 100, 100A: Ultra-fine bubble manufacturing device

Claims

1. An apparatus for producing ultra-fine bubbles, comprising: a storage section having a storage space formed therein for storing liquid and gas; a pressurizing section for compressing the storage space to produce a pressurized gas solution in the storage space in which the gas is pressurized and dissolved in the liquid; a holding section for maintaining the pressurized dissolved state in which the gas is pressurized and dissolved in the liquid; and a decompression section for reducing the pressure of the pressurized gas solution by opening a communication passage that connects the inside and outside of the storage space in the pressurized dissolved state, thereby producing ultra-fine bubbles.

2. The ultra-fine bubble manufacturing device as described in claim 1, wherein the pressurizing unit has a sliding unit that is inserted into the storage unit so as to form the storage space between itself and the storage unit and that can slide within the storage unit along the insertion direction relative to the storage unit, the storage space being compressed by the sliding unit moving relative to the storage unit in the insertion direction, and the holding unit restricts the sliding unit from moving relative to the storage unit in the opposite direction to the insertion direction in the pressurized dissolution state.

3. The ultra-fine bubble manufacturing device as described in claim 2, wherein the pressurizing section has a threaded shaft section extending along the insertion direction and having a male thread groove formed on its outer periphery, the holding section has a threaded hole section into which the threaded shaft section is inserted and has a female thread groove formed therein that screws into the male thread groove of the threaded shaft section, and the threaded shaft section screws into the threaded hole section, causing the sliding section to move relative to the accommodating section in the insertion direction as the threaded shaft section screws into the threaded hole section.

4. An apparatus for producing ultra-fine bubbles as described in claim 1 or 2, wherein the pressure reduction section comprises a valve body capable of changing its state from a closed state in which the communicating passage is blocked to an open state in which the communicating passage is opened, and a drive section that imparts energy to the valve body for changing the valve body from the closed state to the open state.

5. The ultra-fine bubble producing device of claim 4, wherein the valve body fits into the communicating passage in the closed state to block the communicating passage, and the drive unit changes the valve body from the closed state to the open state by pushing the valve body from the outside to the inside of the storage space.

6. The ultra-fine bubble producing device according to claim 4, wherein the drive unit has an igniter which burns an ignition charge when supplied with operating power, and imparts the combustion energy of the ignition charge to the valve body.

7. The ultra-fine bubble producing device according to claim 4, wherein the drive unit has an elastic body that imparts elastic energy to the valve body by restoring it from a compressed state to an elongated state that is more elongated than the compressed state.

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