Ultrafine bubble production device

Abstract

The present invention improves the performance of an ultrafine bubble production device. This ultrafine bubble production device comprises: a storage part that has one end closed and that has formed therein a storage space in which a liquid and a gas are stored; a drive part that compresses the storage space and generates energy for pressurizing and dissolving the gas in the liquid; and a plunger part that closes the one end of the storage part and compresses the storage space by sliding inside of the storage part by means of the energy, and that decompresses the storage space, after compressing the storage space, to generate ultrafine bubbles.

Description

Ultra-fine bubble manufacturing equipment

[0001] The present disclosure relates to an apparatus for producing ultrafine bubbles.

[0002] In recent years, application technologies for microbubbles have been attracting attention. Since around 2004, they have been put to practical use in cleaning, fishing, and agriculture, and their applications have expanded to a wide range of fields, including food and medicine. In response to requests from industry, the Ministry of Economy, Trade and Industry (METI) decided in 2012 to support and promote international standardization activities related to microbubbles. Furthermore, in 2013, the International Organization for Standardization (ISO) established the Fine Bubble Technology Committee, which has been studying various definitions and standardization of "microbubbles." One example is that, while bubbles were not previously clearly distinguished based on their size, academic research and technological advances have led to the standardization of bubbles with diameters of less than 100 μm as fine bubbles, distinguishing them from other bubbles, and furthermore, bubbles with diameters of less than 1 μm as ultrafine bubbles. (Non-Patent Documents 1 and 2)

[0003] Furthermore, a conventional apparatus for producing ultrafine bubbles has been proposed, which includes a storage section for storing a liquid and a gas, and a drive section for pressurizing the interior of the storage section, in which 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 (Patent Document 1).

[0004] International Publication No. 2021 / 090833

[0005] Ultrafine Bubbles, Journal of the Acoustical Society of Japan, Vol. 73, No. 7 (2017), What are Fine Bubbles?, [online], Fine Bubble Society Union, [Retrieved April 10, 2023], Internet <http: / / www.fb-union.org / about.html>

[0006] The present disclosure aims to provide a technique for improving the performance of an ultrafine bubble manufacturing device.

[0007] The ultrafine bubble-producing device according to the present disclosure can be realized in the following manner. That is, the gist of the technology according to the present disclosure is as follows: [1] An ultrafine bubble-producing device comprising: a storage section having an internal storage space for storing a liquid and a gas and one end of which is closed; a drive section that generates energy for compressing the storage space and pressurizing and dissolving the gas in the liquid; and a plunger section that closes the one end of the storage section and slides inside the storage section using the energy to compress the storage space, and that, after compressing the storage space, reduces the pressure of the storage space to generate ultrafine bubbles. [2] The ultrafine bubble-producing device according to [1], wherein the plunger section includes a pressure reducing valve that opens due to inertial force generated when the plunger section slides inside the storage section. [3] The pressure reducing valve includes a sealing part that closes the one end of the storage part and has a through-hole that forms an air passage when the pressure reducing valve is activated, a valve body that closes the through-hole, and an elastic member that biases the valve body to close the through-hole. [4] The pressure reducing valve is configured to deform and displace the elastic member by the inertial force, thereby opening the through-hole. [5] The pressure reducing valve includes a sealing part that closes the one end of the storage part and has a through-hole that forms an air passage when the pressure reducing valve is activated, and a valve body that closes the through-hole and is detached from the sealing part when the pressure reducing valve is activated. [6] The pressure reducing valve is configured to reduce the diameter of the valve body in the direction in which the plunger part slides due to the energy. [7] The ultrafine bubble manufacturing device according to any one of [3] to [6], wherein a gap is provided between the storage unit and the drive unit, which gap forms part of the air passage when the pressure reducing valve is activated, and the air passage connects the storage space with the outside air.[8] The ultrafine bubble manufacturing device according to any one of [1] to [7], wherein the drive unit has an ignition unit containing an ignition charge that is ignited by an ignition current from an external source, and a piston that pushes the plunger unit into the housing unit, and imparts combustion energy of the ignition charge to the piston.

[0008] According to the disclosed technology, the performance of an ultra-fine bubble manufacturing device can be improved.

[0009] FIG. 1 is a longitudinal sectional view showing an example of an ultra-fine bubble producing apparatus. FIG. 2 is a diagram for explaining an example of an initiator. FIG. 3 is a longitudinal sectional view of the producing apparatus showing a state in which the piston is sliding. FIG. 4 is a diagram for explaining a plunger. FIG. 5 is a longitudinal sectional view of the producing apparatus showing a state in which the pressure reducing valve is open. FIG. 6 is a longitudinal sectional view of the producing apparatus showing a state in which a gap is formed between the plunger portion and the piston. FIG. 7 is a longitudinal sectional view of an example of a producing apparatus according to a second embodiment. FIG. 8 is a longitudinal sectional view of the producing apparatus showing a state in which the piston is sliding. FIG. 9 is a longitudinal sectional view of the producing apparatus showing a state in which the pressure reducing valve is open.

[0010] Embodiments will be described below with reference to the drawings. One embodiment of the present disclosure is an apparatus for producing ultrafine bubbles. The apparatus includes a storage unit having an internal storage space for storing a liquid and a gas and one end of which is closed; a drive unit that generates energy to compress the storage space and pressurize and dissolve the gas in the liquid; and a plunger unit that closes one end of the storage unit, slides inside the storage unit using the energy to compress the storage space, and, after compressing the storage space, decompresses the storage space to generate ultrafine bubbles.

[0011] In this embodiment, "ultrafine bubbles" refer to bubbles with a diameter of less than 1 μm, in accordance with the discussion and definition by Technical Committee TC281 (Fine Bubble Technology) of the International Organization for Standardization (ISO). Although the majority of the bubbles produced by the production apparatus 1 are ultrafine bubbles, the bubbles produced by the production apparatus 1 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 provided by the actuator may be provided by a known pressurization technique. An example of the provided energy may be chemically generated energy, such as combustion energy generated by an oxidation reaction of gunpowder or explosives. Alternatively, the energy for the 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 the 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 the 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. In other words, the energy for the change may be any energy capable of pushing the piston. The energy for the change may be a composite energy that appropriately combines combustion energy, electric energy, internal energy such as elastic energy, and manual (human power) energy. For example, the repulsive force may be obtained by compressing a compression spring with human power.

[0015] <Embodiment 1> Figure 1 is a longitudinal cross-sectional view showing an example of an ultrafine bubble producing apparatus. The ultrafine bubble producing apparatus (hereinafter referred to as the "production apparatus") 1 according to this embodiment includes a storage unit 2 having an internal space, a drive unit 3 that generates energy to compress the internal space of the storage unit 2, and a plunger unit 4 that compresses the internal space of the storage unit 2. The internal space of the storage unit 2 contains a liquid 5 and a gas 6. The plunger unit 4 instantaneously pressurizes the interior of the storage unit 2 using the energy generated by the drive unit 3, dissolving at least a portion of the gas 6 in the liquid 5. The production apparatus 1 also generates ultrafine bubbles from a supersaturated solution by rapidly reducing the pressure inside the storage unit 2. The storage unit 2 and the drive unit 3 may be connected by a connecting member 7. The shape and material of the connecting member 7 are not particularly limited as long as it can secure the storage unit 2 and the drive unit 3 together. A gap may be formed between the storage unit 2 and the drive unit 3 when the storage unit 2 and the drive unit 3 are connected.

[0016] The storage unit 2 is, for example, a cylindrical member with one open end and the other closed end. The storage unit 2 has a storage space 21 therein for storing a liquid 5 and a gas 6. The open end of the storage unit 2 is closed by the plunger portion 4. At one end of the storage unit 2, the cross-sectional shape of the storage space 21 is constant, and the volume of the storage space 21 is reduced by the plunger portion 4, which has substantially the same cross-sectional shape as the storage space 21, sliding inside the storage unit 2. The material of the storage unit 2 is not particularly limited as long as it can withstand the pressure inside the storage unit.

[0017] The drive unit 3 includes a cylindrical housing 31, an initiator (ignition unit) 32 provided at one end of the housing 31, a piston 33 slidably disposed inside the housing 31, and a cap 34 provided at the other end of the housing to prevent the piston 33 from falling off. The initiator 32 generates energy for sliding the piston 33. A combustion chamber 35 is formed inside the housing 31 and between the initiator 32 and the piston 33. A gas generating agent may be accommodated in the combustion chamber 35. The piston 33 slides inside the housing 31 due to the energy generated by the initiator 32. The cap 34 has an opening at the center of its cross section, and when the drive unit 3 is activated, a portion of the piston 33 protrudes from the opening.

[0018] The initiator 32 is, for example, an electric ignition device. FIG. 2 is a diagram illustrating an example of the initiator 32. The initiator 32 includes a storage cup 321, an ignition charge 322, a metal header 323, a charge holder 324, a bridge wire 325, two conductive pins 326, and a resin collar 327. The conductive pin 326 is connected to a power source. The storage cup 321 is a metal member covered with an insulating cover and is a cup-shaped container with one end open. The ignition charge 322 is explosive and is stored in the storage cup 321. The metal header 323 is disposed on the opening side of the storage cup 321, and a cylindrical charge holder 324 is provided at the rear side thereof. A storage chamber 328 is formed inside the storage cup 321, the metal header 323, and the charge holder 324. The ignition charge 322 is sealed in the storage chamber 328. A bridge wire 325 electrically connecting one of the conductive pins 326 and the metal header 323 is wired within the housing chamber 328. The two conductive pins 326 are fixed to the metal header 323 via an insulator 329 so as to be insulated from each other. Furthermore, the opening of the housing cup 321 is protected by a resin collar 327 while maintaining insulation between the conductive pins 326. When a voltage is applied between the two conductive pins 326 from an external power source, a current flows through the bridge wire 325. The current ignites and burns the ignition charge 322. The resulting combustion products, such as flame and combustion gas, split the housing cup 321 and are released into the combustion chamber 35 ( FIG. 1 ).

[0019] The ignition charge 322 may be, for example, any one of the following explosives: zirconium and potassium perchlorate (ZPP), titanium hydride and potassium perchlorate (THPP), titanium and potassium perchlorate (TiPP), aluminum and potassium perchlorate (APP), aluminum and bismuth oxide (ABO), aluminum and molybdenum oxide (AMO), aluminum and copper oxide (ACO), and aluminum and iron oxide (AFO), or a combination of these explosives. These explosives are characterized in that their combustion products are gaseous at high temperatures but do not contain gaseous components at room temperature, so that the combustion products condense immediately after ignition. As a result, during the pressurization process of the liquid and the gas, the temperature and pressure of the combustion products generated by the combustion of the ignition charge can be brought down to near room temperature and pressure in a short time after the pressure applied to the liquid and the gas reaches its initial peak injection force.

[0020] The combustion chamber 35 may contain a gas generating agent that burns to generate gas. Examples of the gas generating agent include a single-base smokeless powder 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 generating agents used in gas generators for airbags and seatbelt pretensioners. The pressure generated within the combustion chamber 35 can be appropriately adjusted by adjusting the amount, shape, size, and arrangement of the gas generating agent.

[0021] The piston 33 includes a first portion 331 and a second portion 332 having an outer diameter smaller than that of the first portion 331. The material of the piston 33 is not particularly limited. The outer diameter of the first portion 331 is approximately the same as the inner diameter of the housing 31. The first portion 331 has a groove for holding an O-ring 333, and the outer periphery of the first portion 331 is connected to the interior of the housing 31 via the O-ring 333. The second portion 332 extends from the first portion 331 in the sliding direction of the piston 33. The tip side of the second portion 332 contacts the plunger portion 4 and pushes the plunger portion 4 into the housing portion 2 when the piston 33 slides. The outer diameter of the second portion 332 is smaller than the opening formed in the cap 34. The outer diameter of the first portion 331 is larger than the opening formed in the cap 34. An O-ring 334 is also disposed around the second portion 332 and adjacent to the first portion 331. The housing 31 and the cap 34 have threads that screw together, and are airtightly connected via an O-ring 335 .

[0022] FIG. 3 is a vertical cross-sectional view of the manufacturing apparatus 1 showing the piston 33 sliding. When voltage is applied to the initiator 32, the internal ignition charge burns, and combustion products are released into the combustion chamber 35. When the internal pressure of the combustion chamber 35 increases due to the combustion products of the initiator 32 or further combustion of the gas generating agent contained in the combustion chamber 35, the piston 33 slides inside the housing 31. The piston 33 can slide inside the housing 31 up to the point where the first portion 331 (strictly speaking, the O-ring 334 adjacent to the first portion 331) contacts the cap 34. Furthermore, as the piston 33 slides, the plunger portion 4 is pushed into the housing portion 2, compressing the housing space 21. At this time, the gas 6 contained in the housing space 21 dissolves in the liquid 5, generating a solution 51.

[0023] The plunger portion 4 closes the open end of the accommodation portion 2 and compresses the accommodation space 21. At least a portion of the plunger portion 4 functions as a pressure reducing portion for reducing the pressure in the accommodation space 21. FIG. 4 is a diagram illustrating the plunger portion 4. FIG. 4A is a perspective view of the plunger portion 4 as viewed from above. FIG. 4B is a perspective view of the plunger portion 4 as viewed from below. FIG. 4C is a longitudinal cross-sectional view of the plunger portion 4. The plunger portion 4 includes a sealing portion 41 having a through-hole, a valve body 42 disposed to penetrate the sealing portion 41, and a spring 43 disposed between the sealing portion 41 and the valve body 42. The sealing portion 41 is made of, for example, resin, but is not limited to, a material. The valve body 42 and the spring 43 are made of, for example, metal, but are not limited to, a material.

[0024] The sealing portion 41 has an outer diameter that is approximately the same as the inner diameter of the accommodation portion 2. The sealing portion 41 has two grooves around its periphery for holding O-rings 411, and the outer periphery of the sealing portion 41 is connected to the interior of the accommodation portion 2 via the two O-rings 411. The sealing portion 41 also has a through-hole in the center of its cross section, which functions as a valve seat. When the sealing portion 41 is inserted into the accommodation portion 2, the through-hole connects the accommodation space 21 to the outside. The sealing portion 41 also includes a first region 412, the inner diameter of which is approximately the same as the first portion 421 of the valve body 42; a second region 413, the inner diameter of which is approximately the same as the outer diameter of the spring 43; and a third region 414, the inner diameter of which is approximately the same as the outer diameter of the second portion 422 of the valve body 42.

[0025] The valve body 42 includes a first portion 421 and a second portion 422. After the second portion 422 is inserted through the through-hole of the sealing portion 41 and the spring 43, it is connected to the first portion 421 to assemble the valve body 42. A receiving hole 4211 is formed inside one end 4213 of the first portion 421 for connecting to one end of the second portion 422. The receiving hole 4211 and one end of the second portion 422 engage with each other to prevent them from slipping out. A slit 4212 is formed in the circumferential side of the receiving hole 4211, notched in the axial direction of the first portion 421. One end of the slit 4212 continues to the end 4213 of the first portion 421. A protrusion 4214 is formed circumferentially on the outer periphery of the first portion 421. The other end of the slit 4212 extends beyond the protrusion 4214. The other end of the second portion 422 has an end 4221 having a cross-sectional diameter larger than that of the through-hole of the sealing portion 41, and a protrusion 4222 having an outer diameter substantially the same as the inner diameter of the through-hole of the sealing portion 41. An O-ring 4223 is held in the groove between the end 4221 and the protrusion 4222. The outer periphery of the end 4221 is tapered, and the diameter decreases toward the tip.

[0026] The spring 43 is, for example, a compression coil spring that expands and contracts in the axial direction of the plunger portion 4, but may be another elastic member. The outer diameter of the first portion 421 of the valve body 42 is larger than the outer diameter of the spring 43. Furthermore, the inner diameter of the third region 414 of the sealing portion 41 is smaller than the outer diameter of the spring 43. Therefore, the spring 43 applies a pressing force between the step portion 416 between the second region 413 and the third region 414 of the sealing portion 41 and one end 4213 of the first portion 421. In other words, before the manufacturing apparatus 1 is operated, the spring 43 biases the valve body 42 so that it closes the through-hole of the sealing portion 41.

[0027] FIG. 5 is a longitudinal cross-sectional view of the manufacturing apparatus 1 showing the pressure reducing valve in an open state. When the plunger portion 4 is pushed by the piston 33 and slides, and then collides with the contents (liquid 5) in the storage portion 2, the inertial force generated when the plunger portion 4 slides causes the valve element 42 to slide within the through-hole of the sealing portion 41 against the spring force of the spring 43. The end portion 4221 of the valve element 42 tapers toward the tip, reducing resistance when the valve element 42 plunges into the liquid 5 in the storage space 21 and facilitating its sliding. Furthermore, the valve element 42 preferably has a relatively large mass to increase the kinetic energy when the valve element 42 plunges into the liquid 5 in the storage space 21. For example, the valve element 42 may be formed of a metal such as brass.

[0028] The valve body 42 slides within the through-hole of the sealing portion 41, thereby opening the through-hole of the sealing portion 41. In FIG. 5 , a through-hole 4224 is formed around the second portion 422 of the valve body 42. At this time, the storage space 21 of the storage portion 2 communicates with the space between the piston 33 and the sealing portion 41 via the air passage formed by the through-hole 4224 and the slit 4212 of the valve body 42. Furthermore, the plunger portion 4 and the piston 33 are not connected, and after the plunger portion 4 collides with the content (liquid 5), the impact separates the contact surfaces, forming a gap between the plunger portion 4 and the piston 33. FIG. 6 is a longitudinal cross-sectional view showing a state in which a gap is formed between the plunger portion 4 and the piston 33. A gap may also be provided between the storage portion 2 and the drive unit 3, for example, at the location indicated by the symbol 8. That is, the outer diameter of the second part 332 of the piston 33 is smaller than the inner diameter of the storage space 21 of the storage section 2, and an air passage can be formed between the slit 4212 and the gap 8, so that the storage space 21 is connected to the outside air when the valve body 42 slides.

[0029] As described above, the sealing part 41, the valve body 42, and the spring 43 function as a pressure reducing part (pressure reducing valve) for reducing the pressure in the storage space 21. The weight of the sealing part 41 and the valve body 42, the spring force of the spring 43, the magnitude of the energy generated by the drive part 3, etc. can be appropriately set depending on, for example, the volume and contents of the storage part 2. The pressure reducing part as described above can rapidly reduce the pressure in the storage space 21, and can precipitate (generate) ultrafine bubbles from a supersaturated solution 52 in which gas 6 at or above its solubility is dissolved in the liquid 5.

[0030] The slit 4212 extends to a length that prevents the spring 43 from being housed within the sealing portion 41 even when the spring 43 is in the most compressed state, thereby ensuring an air passage. For example, a protrusion 4214 may be provided as a restricting portion that limits the sliding of the valve element 42, so that the protrusion 4214 collides with the sealing portion 41 to limit the sliding of the valve element 42, and the slit 4212 extending beyond the protrusion 4214 still ensures an air passage. Alternatively, a step 415 may be provided between the first region 412 and the second region 413 of the sealing portion 41 as a restricting portion that limits the sliding of the valve element 42, so that the step 415 collides with one end 4213 of the first portion 421 of the valve element 42 to limit the sliding of the valve element 42, and the slit 4212 still ensures an air passage.

[0031] After the ultrafine bubbles have been generated, for example, the storage unit 2 is removed from the drive unit 3, and then the plunger unit 4 is removed from the storage unit 2. The contents, including the ultrafine bubbles, contained in the storage space 21 are then discharged. At least a part of the production apparatus 1, such as the storage unit 2 and plunger unit 4, may be a disposable unit.

[0032] Generally, when generating fine bubbles using the pressure dissolution method, the speed of the decompression process after dissolving gas in a liquid by pressurization affects the concentration of fine bubbles. In this embodiment, rapid decompression using the decompression unit increases the number of ultrafine bubbles generated (i.e., prevents the bubbles from becoming too large). This embodiment was able to generate ultrafine bubbles at a concentration of more than 100 billion bubbles per milliliter. The number and particle size of ultrafine bubbles were measured and analyzed using Nanosite (Spectris Inc.). Furthermore, this embodiment generates ultrafine bubbles in an airtight storage space 21, making it suitable for generating ultrafine bubbles in a closed system, such as a sterile environment.

[0033] <Embodiment 2> Fig. 7 is a vertical cross-sectional view showing an example of a manufacturing apparatus according to embodiment 2. Fig. 8 is a vertical cross-sectional view of the manufacturing apparatus showing a state in which the piston 33 slides. Fig. 9 is a vertical cross-sectional view of the manufacturing apparatus showing a state in which the pressure reducing valve is open. Note that components corresponding to those in embodiment 1 are given the same reference numerals, and descriptions thereof will be omitted.

[0034] The plunger portion 4A of the manufacturing apparatus 1A according to this embodiment includes a valve body 42A press-fitted into a sealing portion 41A having a through-hole 417, instead of the valve body 42 and spring 43 described in the first embodiment. The through-hole 417 of the sealing portion 41A is formed along the axial direction of the plunger portion 4A. The sealing portion 41A according to this embodiment may be made of, for example, resin, but is not limited to, a material. The valve body 42A is an axial member provided with an O-ring 4223A on its periphery. The O-ring 4223A seals between the valve body 42A and the sealing portion 41A, improving the airtightness of the storage space 21. The valve body 42A may be made of, for example, metal such as brass, but is not limited to, a material.

[0035] As shown in FIG. 8 , in the manufacturing apparatus 1A, the piston 33 pushes the plunger portion 4A to pressurize the storage space 21 using energy generated by the drive unit 3. The valve body 42A according to this embodiment is press-fitted into the through-hole 417 of the sealing portion 41A so as to be able to fall out during operation of the manufacturing apparatus 1A. As shown in FIG. 9 , if the plunger portion 4A is pushed into the piston 33 and slides, and then collides with the contents (liquid 5) in the storage portion 2, the inertial force generated when the plunger portion 4A slides causes the valve body 42A to separate from the sealing portion 41A. The valve body 42A according to this embodiment also tapers toward its tip, reducing resistance when it plunges into the liquid 5 in the storage space 21. Furthermore, it is preferable that the valve body 42A have a relatively large mass to increase the kinetic energy when it plunges into the liquid 5 in the storage space 21.

[0036] By using the O-ring 4223A, the valve body 42A can be reliably removed from the sealing portion 41A. However, the valve body 42A may be directly press-fitted into the sealing portion 41A without the O-ring 4223A. In this case, at least one of the contact portions between the valve body 42A and the sealing portion 41A may be made of an elastic material. Furthermore, an engagement portion such as a projection or recess may be provided so that the valve body 42A and the sealing portion 41A can engage with each other.

[0037] The manufacturing apparatus 1A according to the second embodiment functions as a pressure reducing valve when the valve element 42A is removed from the sealing portion 41A. That is, the through-hole 417 of the sealing portion 41A serves as an air passage, connecting the storage space 21 with the space 36 within the piston 33, etc. Furthermore, reducing the pressure inside the storage space 21 can increase the number of ultra-fine bubbles generated. The manufacturing apparatus 1A according to the second embodiment allows the cross-sectional area of ​​the air passage to be larger than that of the first embodiment because the valve element 42A falls out of the through-hole 417 (in other words, the valve element 42A does not remain in the through-hole 417). Therefore, the pressure inside the storage space 21 can be reduced more rapidly than in the first embodiment. Furthermore, the valve element 42A has a simpler structure than the valve element 42 of the first embodiment, which contributes to reduced manufacturing costs and improved durability of the device, and ensures more reliable operation of the device.

[0038] <Modifications> The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited by the embodiments, but only by the scope of the claims. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0039] The driving unit 3 is not limited to the above-described configuration. For example, the driving unit 3 may generate energy by releasing the pressure of compressed gas.

[0040] 1, 1A: Manufacturing device 2: Storage section, 21: Storage space 3: Drive section, 31: Housing, 32: Initiator, 33: Piston, 34: Cap, 35: Combustion chamber 4, 4A: Plunger section, 41, 41A: Sealing section, 42, 42A: Valve body, 4212: Slit, 43: Spring 5: Liquid 6: Gas

Claims

1. An apparatus for producing ultra-fine bubbles comprising: a storage section having an internal storage space for storing liquid and gas and one end of which is closed; a drive section which generates energy to compress the storage space and pressurize and dissolve the gas in the liquid; and a plunger section which closes the one end of the storage section and slides inside the storage section using the energy to compress the storage space, and which reduces the pressure in the storage space after compressing the storage space, thereby generating ultra-fine bubbles.

2. The ultra-fine bubble manufacturing device according to claim 1, wherein the plunger portion includes a pressure reducing valve that opens due to the inertial force generated when the plunger portion slides inside the container portion.

3. The apparatus for producing ultra-fine bubbles as described in claim 2, wherein the pressure reducing valve includes a sealing portion that closes the one end of the storage portion and has a through hole that forms an air passage when the pressure reducing valve is operated, a valve body that closes the through hole, and an elastic member that biases the valve body so as to close the through hole.

4. The ultra-fine bubble producing device according to claim 3, wherein the valve body is displaced by deforming the elastic member due to the inertial force, thereby opening the through hole.

5. The apparatus for producing ultra-fine bubbles as described in claim 2, wherein the pressure reducing valve includes a sealing portion that closes the one end of the storage portion and has a through hole that forms an air passage when the pressure reducing valve is operated, and a valve body that closes the through hole and detaches from the sealing portion when the pressure reducing valve is operated.

6. An apparatus for producing ultra-fine bubbles as claimed in any one of claims 3 to 5, wherein the valve body is reduced in diameter in the direction in which the plunger portion slides due to the energy.

7. An apparatus for producing ultra-fine bubbles as described in any one of claims 3 to 5, wherein there is a gap between the storage section and the drive section which forms part of the air passage when the pressure reducing valve is operated, and the air passage connects the storage space with the outside air.

8. An ultra-fine bubble manufacturing device as described in any one of claims 1 to 5, wherein the drive unit has an ignition unit containing an ignition charge that is ignited by an external ignition current, and a piston that pushes the plunger unit into the storage unit, and imparts combustion energy of the ignition charge to the piston.

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