Ultra-fine bubble generating unit and ultra-fine bubble-containing liquid manufacturing device

Abstract

To provide an ultrafine bubble generation unit capable of maintaining stable UFB generation efficiency and generating UFB-containing liquid of high quality with small variance, and a device for manufacturing liquid containing ultrafine bubble.SOLUTION: The number of heat generating elements 1102 arrayed along the direction (arrow F1 direction) of liquid flowing over the heat generating elements 1102 is denoted as n1, and the number of heat generating elements arrayed crossing the arrow F1 direction is denoted as n2. At this time, a heat generating element substrate 1100 of an UFB generation unit 1000 in the present embodiment has relation of n1<n2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an ultra-fine bubble generating unit and an apparatus for producing a liquid containing ultra-fine bubbles (hereinafter also referred to as "UFB") with a diameter of less than 1.0 μm. [Background technology]

[0002] Patent Document 1 discloses a method for generating ultra-fine bubbles with a diameter of less than 1.0 μm (Thermal-Ultra Fine Bubbles; hereinafter also referred to as "T-UFB") by generating film boiling in a liquid by heating a heating element in the liquid. In particular, it discloses that UFBs are efficiently generated by arranging multiple substrates equipped with heating elements along the direction of liquid flow, thereby increasing the total number of heating elements and repeatedly inducing film boiling in accordance with the liquid flow. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-42732 Summary of the Invention [Problem to be solved by the invention]

[0004] As the liquid travels over multiple heating elements arranged on a substrate, it is affected by the heat from the heating elements. Specifically, excess heat generated by bubbling due to film boiling is transferred to the liquid, causing the temperature of the liquid to rise as it travels downstream. As the liquid temperature rises, dissolved gas in the liquid may turn into bubbles, potentially reducing the amount of dissolved gas. As the amount of dissolved gas in the liquid decreases, the amount of UFB produced decreases. However, Patent Document 1 does not mention how to prevent the decrease in the amount of dissolved gas that occurs as the liquid temperature rises.

[0005] In addition, there is also a risk that large-sized bubbles generated by the vaporization of dissolved gas may inhibit foaming due to film boiling in the heating element downstream.

[0006] Therefore, the present invention provides an ultra-fine bubble-containing liquid production apparatus and an ultra-fine bubble generation unit that can maintain a stable UFB generation efficiency and produce a high-quality UFB-containing liquid with little variation.

Means for Solving the Problems

[0007] Therefore, the ultra-fine bubble generation unit of the present invention includes a substrate having a plurality of heating elements, and is an ultra-fine bubble generation unit for generating ultra-fine bubbles in a liquid by causing the heating elements to generate heat and cause film boiling in the liquid. The substrate further includes a supply port for supplying liquid to the heating elements, a flow path for guiding the liquid supplied from the supply port to the heating elements, and a recovery port provided downstream in the first direction with respect to the supply port and for recovering liquid from the heating elements when the direction in which the liquid flows to the heating elements in the flow path is defined as the first direction. The substrates are arranged in a plurality along the first direction. In the flow path, the liquid flows from the supply port through the heating element in the same substrate as the supply port, and to the recovery port in the same substrate as the supply port, without flowing across the adjacent substrates; The ultra-fine bubble generation unit has a common recovery liquid chamber for recovering liquid from the recovery ports of each of the plurality of substrates. In one of the substrates, Let the number of heating elements arranged along the first direction be n1. In one of the substrates, Let the number of heating elements arranged along a second direction, which is a direction intersecting the first direction, be n2. In the plurality of substrates arranged along the first direction, when the number of heating elements arranged along the first direction is n3, in the substrate, n1, n2, and n3 satisfy the relationship n1 < n2 < n3.

Effects of the Invention

[0008] According to the present invention, it is possible to provide an ultra-fine bubble generating unit and an apparatus for producing ultra-fine bubble-containing liquid that can maintain stable UFB generation efficiency and produce high-quality UFB-containing liquid with little variation. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an apparatus for producing ultra-fine bubble-containing liquid. [Figure 2] FIG. 2 is a perspective view of a UFB generation unit. [Figure 3] FIG. 2 is a perspective view of a UFB generation unit. [Figure 4] FIG. 2 is an exploded perspective view of the UFB generation unit. [Figure 5] FIG. 2 is an exploded perspective view of the heating element substrate. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 2 is an external view of the housing showing the interior. [Figure 8] This is a cross-sectional view of the UFB generation unit with the liquid flow direction facing vertically upward. [Figure 9] FIG. 10 is a diagram showing a modified example of a heating element substrate. [Figure 10] FIG. 10 is a diagram showing a modified example of a heating element substrate. [Figure 11] 1 is a schematic diagram showing the configuration of a UFB-containing liquid manufacturing apparatus. [Figure 12] FIG. 2 is a perspective view showing a UFB generating unit. [Figure 13] FIG. 2 is a perspective view showing a UFB generating unit. [Figure 14] FIG. 2 is an exploded perspective view of the UFB generation unit. [Figure 15] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. [Figure 16] FIG. 2 is a cross-sectional view showing a UFB generating unit. [Figure 17] 1 is a schematic diagram showing the configuration of a UFB-containing liquid manufacturing apparatus. [Figure 18]FIG. 2 is a perspective view showing the appearance of the UFB generation unit. [Figure 19] FIG. 2 is an exploded perspective view of the UFB generation unit. [Figure 20] FIG. 2 is an exploded perspective view of the heating element substrate. [Figure 21] FIG. 19 is a cross-sectional view taken along line XXI-XXI in FIG. 18. [Figure 22] FIG. 2 is a perspective view showing the appearance of the UFB generation unit. [Figure 23] FIG. 2 is an exploded perspective view of the UFB generation unit. [Figure 24] FIG. 2 is an exploded perspective view of the heating element substrate. [Figure 25] FIG. 2 is a cross-sectional view of a UFB generation unit. [Figure 26] 10A and 10B are diagrams illustrating the flow of liquid in the heating element substrate. [Figure 27] FIG. 2 is a perspective view showing the appearance of the UFB generation unit. [Figure 28] FIG. 2 is an exploded perspective view of the UFB generation unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

[0011] 1 is a schematic diagram showing the configuration of an apparatus for producing ultra-fine bubble-containing liquid (hereinafter referred to as UFB-containing liquid producing apparatus) 2000 according to this embodiment. The apparatus for producing UFB-containing liquid 2000 mainly includes a liquid supply section 600, a gas dissolving section 800, a storage chamber 900, and an ultra-fine bubble generating unit (hereinafter referred to as UFB generating unit) 1000. In FIG. 1, solid arrows indicate the flow of liquid, and dashed arrows indicate the flow of gas.

[0012] The liquid supply unit 600 mainly includes a liquid storage unit 601, two pumps 602 and 603, and a degassing unit 604. The liquid W stored in the liquid storage unit 601 is sent by the pump 602 to the storage chamber 900 via the degassing unit 604. A membrane that only allows gas to pass through is provided inside the degassing unit 604, and by reducing the pressure with the pump 603, only the gas passes through the membrane, separating the gas and the liquid. After separation, the liquid W flows toward the storage chamber 900, and the gas is discharged to the outside. The liquid stored in the liquid storage unit 601 may contain various dissolved gases. However, by removing the dissolved gases with the degassing unit 604 before sending the liquid to the storage chamber 900, the dissolution efficiency of the gas dissolving step that is performed later can be improved.

[0013] Gas dissolving unit 800 includes gas supply unit 804, pre-treatment unit 801, confluence unit 802, and gas-liquid separation chamber 803. Gas supply unit 804 may be a cylinder that stores desired gas G, or may be a device that can continuously generate desired gas G. For example, if the desired gas G is oxygen, the device can take in air, remove nitrogen, and continuously pump out the nitrogen-removed gas.

[0014] The gas G supplied from the gas supply unit 804 is subjected to treatment such as discharge in the pretreatment unit 801, and then merges with the liquid W flowing out of the storage chamber 900 in the merging unit 802. At this time, part of the gas G dissolves in the liquid W. The merged gas G and liquid W are separated again in the gas-liquid separation chamber 803, and only the gas G not dissolved in the liquid W is discharged to the outside. The liquid W with the dissolved gas G is then sent to the UFB generation unit 1000 by the pump 703. A solubility sensor 805 for detecting the solubility of the gas G in the liquid W is provided downstream of the gas-liquid separation chamber 803.

[0015] The storage chamber 900 contains a mixture of the liquid W supplied from the liquid supply unit 600, the liquid W in which the desired gas G has been dissolved in the gas dissolver 800, and the UFB-containing liquid in which T-UFB has been produced in the UFB production unit 1000. A temperature sensor 905 detects the temperature of the liquid W contained in the storage chamber 900. A liquid level sensor 902 is disposed at a predetermined height in the storage chamber 900 and detects the liquid level of the liquid W. A UFB concentration sensor 906 detects the UFB concentration of the liquid W contained in the storage chamber 900. A valve 904 is opened when the liquid W contained in the storage chamber 900 is discharged into an external container (not shown). Although not shown, a stirring means may be provided inside the storage chamber 900 to uniformly distribute the temperature and UFB of the liquid W.

[0016] The cooling unit 903 cools the liquid W contained in the storage chamber 900. In order to efficiently dissolve the desired gas G in the gas dissolver 800, it is preferable that the temperature of the liquid W supplied to the gas dissolver 800 be as low as possible. Furthermore, by maintaining the temperature of the circulating liquid W at a low temperature, it is possible to suppress a temperature rise in the liquid W in the UFB generation unit 1000, which generates UFB using film boiling, and to extend the life of the UFB generation unit 1000. In this embodiment, the temperature of the liquid W is detected by the temperature sensor 905, and the temperature of the liquid W supplied to the gas dissolver 800 is adjusted to 10°C or below using the cooling unit 903.

[0017] The configuration of the cooling unit 903 is not particularly limited, but for example, a system using a Peltier element or a system circulating a liquid cooled by a chiller can be adopted. In the latter case, a cooling pipe for circulating the cooling liquid may be wound around the outer periphery of the accommodation chamber 900 as shown in Fig. 1, or the accommodation chamber 900 may have a hollow structure and the cooling pipe may be disposed within the hollow. Alternatively, the cooling pipe may be immersed in the liquid W in the accommodation chamber 900.

[0018] The UFB generation unit 1000 generates UFB in the liquid W that has flowed in. In this embodiment, the T-UFB method, which utilizes film boiling, is used as the UFB generation method. A filter 1001 is disposed upstream of the UFB generation unit 1000, and this filter 1001 prevents impurities, debris, etc. from flowing into the UFB generation unit 1000. By removing impurities, debris, etc. using the filter 1001, the UFB generation efficiency in the UFB generation unit 1000 can be improved.

[0019] The above-mentioned components are connected by piping 700, and pumps 702, 703, and 704 are provided to form a path for circulating liquid W. FIG. 1 shows a case in which circulation path A for dissolving gas and circulation path B for generating UFB are formed. In this case, in circulation path A, liquid W is circulated at a flow rate of approximately 300 to 3000 mL / min and a pressure of approximately 0.2 to 0.6 MPa to efficiently dissolve gas. In circulation path B, liquid W is circulated at a flow rate of approximately 10 to 300 mL / min and a pressure of approximately 0.1 to 0.3 MPa. The T-UFB method generates UFB by utilizing the pressure difference and heat generated during the foaming and defoaming process due to film boiling, so a relatively low speed and low pressure (atmospheric pressure) are preferable as circulation conditions.

[0020] 1 shows a configuration in which a circulation path A for dissolving the gas is provided, a configuration in which a certain amount of gas G is directly supplied to the containing chamber 900 may also be used. This makes it possible to realize a more compact UFB-containing liquid manufacturing apparatus.

[0021] The position and number of pumps are not limited to those shown in FIG. 1. Furthermore, pumps and valves necessary for the operation of each part may be provided as appropriate within the configuration of each part. However, it is preferable to use a pump with minimal pulsation and flow rate variation so as not to impair the UFB production efficiency. Furthermore, the recovery path and valve 904 for recovering liquid W may be provided at a position other than the storage chamber 900 in the liquid circulation path. Furthermore, if the temperature of the UFB production unit 1000 rises rapidly, a cooling unit similar to that of the storage chamber 900 may also be provided in the UFB production unit 1000.

[0022] The solubility sensor 805, temperature sensor 905, and UFB concentration sensor 906 may be installed at other locations within the circulation path. These sensors may be installed at multiple locations within the circulation path and configured to output average values. Components that come into contact with the UFB-containing liquid, such as the piping 700, pumps 702, 703, and 704, filter 1001, storage chamber 900, and UFB generation unit 1000, are preferably made of highly corrosion-resistant materials. For example, fluororesins such as polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkane (PFA), metals such as SUS316L, and other inorganic materials are suitable. This allows for efficient UFB generation even when highly corrosive gas G or liquid W is used.

[0023] 2 and 3 are perspective views of the UFB generation unit 1000 in this embodiment, and Fig. 4 is an exploded perspective view of the UFB generation unit 1000. Fig. 5 is an exploded perspective view of the heating element substrate 1100, and Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 2.

[0024] As shown in Fig. 4, the UFB generation unit 1000 in this embodiment includes a heating element substrate 1100, a flexible wiring substrate 1200, a support member 1300, a housing 1400, an electric substrate 1500, and a cover 1600. The heating element substrate 1100 is formed by stacking a first flow path member 1110 (see Fig. 5) and a Si substrate 1101, and a large number of heating elements 1102 (see Fig. 5) and electrodes 1103 (see Fig. 5) are provided on the Si substrate 1101. The heating elements 1102 and the electrodes 1103 are connected by wiring (not shown). An electric signal is sent from the electrode 1103 at a desired timing to drive the heating elements 1102 (see Fig. 5). In addition, the Si substrate 1101 is formed with a supply port 1104a (see FIG. 5) that can supply liquid to the heat generating element 1102, and a recovery port 1105a (see FIG. 5) that can recover the liquid W that has passed through the heat generating element 1102.

[0025] The supply ports 1104a are connected to the supply channel 1104 (see FIG. 6) at their bottoms and communicate with each other. The recovery port 1105a is also connected to the recovery channel 1105 and communicates with each other. With this configuration, Si beams are formed between the supply ports 1104a and the recovery ports 1105a. These beams maintain the rigidity of the Si substrate 1101 and serve as a path for wiring. A first flow path member 1110 (see FIGS. 5 and 6) is provided above the Si substrate 1101, and flow paths 1111 (see FIG. 6) are formed therein for guiding liquid to the heat generating elements 1102. All of these are formed with high dimensional accuracy by a photolithography process. The support member 1300 (see FIGS. 4 and 6) is made of a material such as alumina, and supports and fixes the heat generating element substrates 1100 while also dissipating heat generated by the heat generating elements 1102. Support member 1300 is provided with supply path 1301 and recovery path 1302 at positions corresponding to supply path 1104 and recovery path 1105 (see FIG. 6).

[0026] FIG. 7 is a perspective view of the housing 1400 viewed from the longitudinal direction so that the interior can be seen. The housing 1400 is formed from a molded member and is provided with a common liquid supply chamber 1401 and a common liquid recovery chamber 1402 corresponding to the multiple heating element substrates 1100, and is provided with connectors 1403 and 1404 for fluid connection to the outside. The liquid supply chamber 1401 and the liquid recovery chamber 1402 are tapered as shown in FIG. 7, so that liquid W at approximately the same temperature is stably supplied to each heating element substrate 1100. An electric signal (power) is sent to the heating element substrate 1100 via an electric board 1500 and a flexible wiring board 1200 (see FIG. 4). Connectors 1502 and 1503 (see FIG. 4) are formed on the electric board 1500, and are electrically connected to the UFB generation unit drive unit. The connector 1501 is also connected to a terminal 1202 of the flexible wiring board 1200.

[0027] Terminals 1201 of flexible wiring board 1200 and electrodes 1103 of heating element board 1100 are electrically connected by wire bonding or the like and sealed with sealant 1700 (see FIG. 2). Electrical board 1500 is protected by cover 1600 (see FIG. 2) made of a molded member, sheet metal, or the like. UFB generation unit 1000 can be easily detached from UFB-containing liquid manufacturing apparatus 2000. In this specification, a member consisting of one heating element board 1100 and one flexible wiring board 1200 is referred to as a UFB generation module. A plurality of such UFB generation modules can be arranged in UFB generation unit 1000, and this embodiment shows an example in which five ultra-fine bubble generation modules are arranged in the longitudinal direction.

[0028] As shown in FIG. 6, the liquid W supplied to the UFB generation unit 1000 is sent to the heating element 1102 through the supply liquid chamber 1401, the supply path 1301, the supply path 1104, and the flow path 1111. Then, it is recovered through the flow path 1111, the recovery path 1105, the recovery path 1302, and the recovery liquid chamber 1402. That is, above the heating element 1102, the liquid W flows in the direction of arrow F1. The direction of arrow F1 is the short side direction of the heating element substrate 1100, and is also the short side direction in the arrangement of the heating elements 1102.

[0029] In the case of the configuration in which the flow path member 1110 in which the flow paths of the liquid are formed is stacked on the Si substrate 1101 on which a plurality of heating elements are arranged as in the present embodiment, the UFB generation unit 1000 can be made compact, but it is difficult to suppress the temperature rise of the liquid under the limited flow path volume. Therefore, in the present embodiment, the number of heating elements 1102 arranged in the short side direction (direction of arrow F1) of the heating element substrate 1100 is made smaller than the number of heating elements 1102 arranged in the longitudinal direction (direction of arrow WD1 (see FIG. 5)) of the heating element substrate 1100. Here, as shown in FIG. 4, let the number of heating elements 1102 arranged along the direction of the liquid W flowing above the heating element 1102 (direction of arrow F1) be n1, and the number of heating elements arranged intersecting the direction of arrow F1 be n2. At this time, in the heating element substrate 1100 of the UFB generation unit 1000 in the present embodiment, it is configured such that the relationship of n1 < n2 holds.

[0030] Here, the number n1 of heater elements 1102 arranged in the direction of arrow F1 can be calculated by estimating the temperature rise of the liquid during UFB generation in the flow path 1111 based on the amount of dissolved gas, the temperature of the supplied liquid, the drive frequency of the heater elements, and other factors. Specifically, the number n1 heater elements can be set to a value that minimizes the difference in UFB generation rate between upstream and downstream of the liquid flowing over the n1 heater elements. The number of heater element substrates 1100 can be determined arbitrarily based on the desired UFB-containing liquid production capacity. By limiting the number of heater elements 1102 along the direction of arrow F1, the temperature rise of the liquid during UFB generation in the flow path 1111 can be suppressed, thereby minimizing the decrease in the amount of dissolved gas in the liquid. This allows the total number of heater elements 1102 in the UFB generation unit 1000 to be increased without causing a difference in UFB generation quality between upstream and downstream of the liquid W flow, enabling stable UFB generation without sacrificing efficiency.

[0031] The direction of arrow WD1 (see FIG. 5) is preferably perpendicular to the direction of arrow F1, which allows for a compact UFB generation unit 1000. However, this is not limited to this, and the directions may intersect at an angle of approximately 45° to 90°. Furthermore, the shape of the heating element substrate 1100 is not limited to a rectangle and may be any shape.

[0032] Although FIG. 4 shows an arrangement of multiple heating element substrates 1100, a single heating element substrate 1100 may be configured with heating elements 1102 equivalent to the number of heating element substrates 1100 arranged. The timing of driving (bubbling) the multiple heating elements 1102 can be appropriately adjusted. For example, if driven at a relatively low frequency, all heating elements 1102 can be driven simultaneously. Furthermore, if driven at a relatively high frequency, the heating elements can be driven with a delay of several microseconds to prevent a large current from flowing and a voltage drop. In this case, the heating elements 1102 can be driven sequentially, starting with the downstream heating element 1102 and then the upstream heating element 1102. If the downstream heating element 1102 is driven first, the temperature of the nearby liquid W rises slightly, but the heated liquid W moves downstream due to the liquid flow (flow in the direction of arrow F1). Therefore, the upstream heating element 1102 is less susceptible to the temperature rise caused by the downstream heating element 1102, enabling more accurate UFB generation.

[0033] FIG. 8 is a cross-sectional view of the UFB generation unit 1000 when the flow direction of the liquid W (indicated by the arrow F1) is vertically upward. The orientation (posture) of the UFB generation unit 1000 during UFB generation may be determined arbitrarily. For example, as shown in FIG. 8, the flow direction of the liquid W (indicated by the arrow F1) in the heating element 1102 may be vertically upward. With this configuration, even if unintended large bubbles are mixed inside the UFB generation unit 1000 or bubbles are generated in the flow path 1111 due to an increase in the liquid temperature, the bubbles are sent to the recovery path 1105 by buoyancy. This minimizes the obstruction of foaming in the heating element 1102, enabling stable UFB generation.

[0034] (Variation) Figs. 9 and 10 are diagrams showing the heating element substrate 1100 of a modified example of the present embodiment. In the heating element substrate 1100 shown in Fig. 9, a partition portion 1106 is provided along the direction of arrow F1 between adjacent heating elements 1102 in the direction of arrow WD1. By providing such a partition portion 1106, the flow of the liquid in the direction of arrow WD1 can be suppressed, and the temperature rise of the liquid W can be suppressed, so that UFB can be generated more stably.

[0035] Further, in the heating element substrate 1100 shown in Fig. 10, a partition portion 1107 is provided so as to surround the areas other than the direction of arrow F1 around each heating element 1102. By providing such a partition portion 1107, it is made difficult to be affected by the foaming of the adjacent heating elements 1102 in the direction of arrow F1, the defoaming of the generated UFB is suppressed, and UFB can be generated more stably even when the heating element 1102 is driven at a high frequency.

[0036] Thus, let the number of heating elements 1102 arranged along the direction of the liquid flowing above the heating element 1102 (direction of arrow F1) be n1, and the number of heating elements arranged intersecting the direction of arrow F1 be n2. At this time, in the heating element substrate 1100 of the UFB generation unit 1000 in the present embodiment, it is configured such that the relationship n1 < n2 holds. Thereby, it is possible to provide a heating element substrate, an ultra-fine bubble generation unit, and an ultra-fine bubble-containing liquid manufacturing apparatus that can maintain a stable UFB generation efficiency in the flow path 1111 and generate a high-quality UFB-containing liquid with little variation.

[0037] (Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0038] 11 is a schematic diagram showing the configuration of a UFB-containing liquid manufacturing apparatus 2000 according to this embodiment. In the UFB-containing liquid manufacturing apparatus 2000 according to this embodiment, the produced UFB-containing liquid is not collected in the accommodation chamber 900 but is used as the UFB-containing liquid as is.

[0039] 12 and 13 are perspective views showing the UFB generation unit 1000 of this embodiment, and Fig. 14 is an exploded perspective view of the UFB generation unit 1000. Fig. 15 is a cross-sectional view taken along line XIV-XIV in Fig. 12. Note that in Fig. 14, the electric board 1500 and the cover 1600 are omitted because they are the same as those in the first embodiment.

[0040] In the UFB generation unit 1000 of this embodiment, a discharge port 1112 is provided in a first flow path member 1110 at a position corresponding to the heating element 1102. When the heating element 1102 is driven to cause bubbles to form in the liquid W, the liquid W containing UFBs above the heating element 1102 can be discharged from the discharge port 1112, and the liquid W is discharged in the form of fine droplets from the discharge port 1112. These discharged fine droplets can be used as a mist of UFB-containing liquid.

[0041] The UFB generation unit 1000 of this embodiment is configured so that the UFB-containing liquid is not recovered into the storage chamber 900. Therefore, no connection part for recovery is provided, and instead, a supply connection part 1403 (see FIG. 13) and a supply liquid chamber 1401 (see FIG. 14) for supply are formed in the housing 1400. The shape of the support member 1300 is the same as that shown in the first embodiment, but all openings function as supply channels 1301. The Si substrate 1101 is also not provided with a recovery channel, but is provided with a supply channel 1104 (see FIG. 15) used for supplying the liquid. Therefore, the flow of the liquid W above the heating element 1102 is in the direction of arrow F2 shown in FIG. 15.

[0042] In this embodiment, when the liquid W is bubbled by the driving of the heating element 1102, the liquid W containing the UFBs above the heating element 1102 is ejected from the outlet 1112 as fine droplets. If all of the liquid W heated by the driving of the heating element 1102 were ejected from the outlet 1112, the liquid W would not be repeatedly heated, and the temperature rise would have almost no effect on the generation of UFBs. However, in reality, not all of the liquid W heated by the bubble generation is ejected from the outlet 1112; some liquid W is heated but not ejected. Therefore, the heated liquid W that was not ejected is heated again by driving the heating element 1102. Therefore, to suppress the heating of the liquid and stably generate UFBs, it is effective to keep the number of heating elements 1102 arranged along the direction of arrow F2 to n1, as in this embodiment.

[0043] (First Modification) FIG. 16 is a cross-sectional view of the UFB generation unit 1000, illustrating a first modification of this embodiment. As shown in FIG. 16, the number of supply channels 1301 and 1104 can be arbitrarily determined, and the number of supply channels 1301 and 1104 may be increased. In this manner, increasing the number of supply channels 1301 and 1104 increases the number of heating elements 1102 in the direction of arrow F2, thereby increasing the amount of UFB generated. In this modification, the number n1 of heating elements 1102 arranged along the direction of the liquid flow (the direction of arrow F2) is the number of heating elements 1102 between adjacent supply channels 1104. That is, in the case of FIG. 16, n1 = 3. Furthermore, by appropriately adjusting the flow path widths of the supply channels 1301 and 1104, it is possible to reduce the in-plane temperature distribution of the heating element substrate 1100.

[0044] (Second Modification) 17 is a schematic diagram showing a UFB-containing liquid manufacturing apparatus 2000, illustrating a second modified example of this embodiment. As shown in FIG. 17, a recovery member 1002 for recovering the UFB-containing liquid discharged from the discharge port 1112 of the UFB generation unit 1000 may be brought into contact with the UFB generation unit 1000, and the discharged microdroplets may be recovered in the storage chamber 900. The UFB-containing liquid having a desired concentration after circulation can be taken out from the storage chamber 900 by opening the valve 904, or the recovery member 1002 can be removed and the discharged UFB-containing liquid can be used as a mist.

[0045] (Third embodiment) The third embodiment of the present invention will be described below with reference to the drawings. Note that the basic configuration of this embodiment is the same as that of the first embodiment, so only the characteristic configuration will be described below.

[0046] Fig. 18 is a perspective view showing the appearance of the UFB generation unit 1000 in this embodiment, and Fig. 19 is an exploded perspective view of the UFB generation unit 1000. Fig. 20 is an exploded perspective view of the heating element substrate 1100 in this embodiment, and Fig. 21 is a cross-sectional view taken along line XXI-XXI in Fig. 18.

[0047] The heater element substrate 1100 of this embodiment includes a first flow path member 1110 and a second flow path member 1120. The first flow path member 1110 has a discharge port 1112 and a recovery path 1113 formed therein, and the second flow path member 1120 has a flow path 1121 (see FIG. 21 ). With this configuration, the UFB-containing liquid discharged from the discharge port 1112 can be recovered and circulated without using the recovery member 1002 used in the second embodiment. This allows the UFB-containing liquid manufacturing apparatus 2000 to be made smaller and at lower cost.

[0048] (Fourth embodiment) The fourth embodiment of the present invention will be described below with reference to the drawings. Note that the basic configuration of this embodiment is the same as that of the first embodiment, so only the characteristic configuration will be described below.

[0049] Fig. 22 is a perspective view showing the appearance of the UFB generation unit 1000 in this embodiment, Fig. 23 is an exploded perspective view of the UFB generation unit 1000, and Fig. 24 is an exploded perspective view of the heating element substrate 1100. Fig. 25(a) is a cross-sectional view taken along line XXVa-XXVa in Fig. 22, and Fig. 25(b) is a cross-sectional view taken along line XXVb-XXVb in Fig. 22. Fig. 26 is a diagram illustrating the flow of liquid in the heating element substrate 1100.

[0050] In each of the above embodiments, the heater element substrate 1100 was arranged so that the longitudinal direction of the UFB generation unit 1000 and the longitudinal direction of the heater element substrate 1100 were the same direction, but in this embodiment, the orientation of the heater element substrate 1100 relative to the UFB generation unit 1000 is different. Specifically, as shown in Fig. 22, the heater element substrate 1100 is arranged so that the longitudinal direction of the UFB generation unit 1000 and the short side direction of the heater element substrate 1100 are the same direction.

[0051] 24, the heating element substrate 1100 in this embodiment is provided with a third flow path member 1130 on the back surface (the surface opposite to the direction in which the liquid W is discharged) of the heating element substrate 1100. A supply port (supply opening) 1131 and a recovery port (recovery opening) 1132 are formed in the third flow path member 1130. As a result, a portion of the supply path 1104 and the recovery path 1105 are covered by the flow path member 1130. Furthermore, a supply path 1301 and a recovery path 1302 are formed in the support member 1300 at positions corresponding to the supply port 1131 and the recovery port 1132.

[0052] The liquid W supplied from the supply liquid chamber 1401 of the housing 1400 is supplied in sequence to the supply port 1301 of the support member 1300, the supply port 1131 of the third flow path member 1130, and the supply path 1104 of the Si substrate 1101. The liquid W supplied to the supply path 1104 spreads in the direction of arrow WD within the supply path 1104, flows over the heating element 1102 of the Si substrate 1101, and as shown in FIG. 26, the liquid W flows in the direction of arrow F4. Thereafter, it flows from the recovery path 1105 shown in FIG. 25 to the recovery port 1132, and the liquid W is recovered from the UFB generation unit 1000 via the recovery path 1302 and the recovery liquid chamber 1402.

[0053] Here, as shown in FIG. 23, in one heating element substrate 1100, let the number of heating elements 1102 arranged in the direction of arrow F4, which is the direction in which liquid flows over the heating element 1102, be n1, and the number of heating elements arranged in the direction of arrow WD4 that intersects the direction of arrow F4 be n2. Also, let the total number of heating elements in the direction of arrow F4 when a plurality of heating element substrates 1100 are arranged along the direction of arrow F4 be n3. At this time, in the UFB generation unit 1000 in the present embodiment, it is configured such that the relationship n1 < n2 < n3 holds.

[0054] With such a configuration, since the number of heating elements 1102 arranged in the direction of arrow WD4 can be increased, more heating elements 1102 can be mounted on the heating element substrate 1100, and the UFB generation amount can be increased. <>

[0055] Also, as in the modified example of the first embodiment shown in FIGS. 9 and 10, partition portions 1106 and 1107 may be provided. By providing the partition portions 1106 and 1107, the flow of the liquid in the direction of arrow WD4 can be suppressed, and since the temperature rise of the liquid W can be suppressed, UFB can be generated more stably.

[0056] (The Fifth Embodiment) Hereinafter, the fifth embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0057] Fig. 27 is a perspective view showing the appearance of the UFB generation unit 1000 of this embodiment, and Fig. 28 is an exploded perspective view of the UFB generation unit 1000. As in the second embodiment, the UFB generation unit 1000 of this embodiment is configured such that a first flow path member 1110 has outlets 1112 at positions corresponding to the heating elements 1102, and when bubbles are generated by the heating elements 1102, microdroplets are ejected from the outlets 1112. The relationship between the arrangement of the heating element substrates 1100 and the number of heating elements 1102 is the same as that shown in the fourth embodiment.

[0058] However, what differs from the fourth embodiment is that a third flow path member 1130 (see FIG. 24) is not provided. In this embodiment, a third flow path member 1130 is not provided. Also, in the fourth embodiment, a supply path 1104 and a recovery path 1105 are formed as flow paths of the same shape in the Si substrate 1101, but in this embodiment, both function as supply paths (not shown). Furthermore, openings corresponding to the supply paths are formed in the support member 1300, and both function as supply paths 1301 (see FIG. 28) for supplying the liquid W.

[0059] This configuration allows stable generation of UFBs, and the ejected microdroplets can be used as a mist of UFB-containing liquid. Furthermore, by applying the first modification of the second embodiment, the number of heating elements 1102 can be increased, thereby increasing the amount of UFBs generated. Furthermore, by applying the second modification of the second embodiment to this embodiment, it is possible to open the valve 904 and extract the UFB-containing liquid, which has been circulated to a desired concentration, from the storage chamber 900. Furthermore, it is also possible to remove the recovery member 1002 and use the ejected UFB-containing liquid as a mist. [Explanation of symbols]

[0060] 900 Containment Room 1000 UFB generating units 1100 Heating element board 1101 Si substrate 1102 Heating element 1106 Partition 1107 Partition 1112 Discharge port 1500 Electrical Board 2000 UFB-containing liquid production equipment

Claims

1. An ultra-fine bubble generating unit comprising a substrate having a plurality of heating elements, the heating elements generating heat to cause film boiling in a liquid, thereby generating ultra-fine bubbles in the liquid, The substrate further comprises: a supply port for supplying a liquid to the heating element; a flow path for guiding the liquid supplied from the supply port to the heating element; a recovery port that is provided downstream of the supply port in a first direction in which the liquid flows through the flow path toward the heat generating element, and that recovers the liquid from the heat generating element; and a plurality of the substrates are arranged along the first direction, the flow path is configured so that the liquid flows from the supply port through the heating element in the same substrate as the supply port to the recovery port in the same substrate as the supply port without flowing across adjacent substrates; the ultra-fine bubble generating unit has a common recovery liquid chamber for recovering liquid from the recovery ports of the plurality of substrates, The number of the heat generating elements arranged along the first direction on one of the substrates is defined as n1, The number of the heat generating elements arranged on one substrate along a second direction that intersects with the first direction is defined as n2, In the plurality of substrates arranged along the first direction, when the number of the heat generating elements arranged along the first direction is n3, An ultra-fine bubble generating unit characterized in that in the substrate, n1, n2, and n3 satisfy the relationship n1<n2<n3.

2. The ultra-fine bubble generating unit according to claim 1, wherein a partition wall separating the heating elements adjacent in the second direction is provided along the first direction between the heating elements adjacent in the second direction.

3. The ultra-fine bubble generating unit according to claim 2 , wherein the partition wall is provided to surround each of the heating elements in all directions other than the first direction.

4. 4. The ultra-fine bubble generating unit according to claim 1, wherein the substrate is formed by stacking, on an element substrate on which the heating element is arranged, a first flow path member in which the flow path is formed, and a third flow path member having a supply opening capable of supplying liquid to the supply port and a recovery opening capable of recovering the liquid heated by the heating element.

5. The ultra-fine bubble generating unit according to any one of claims 1 to 4, wherein the n1 heating elements arranged along the first direction are simultaneously driven.

6. The ultra-fine bubble generating unit according to any one of claims 1 to 4, wherein the n1 heating elements arranged along the first direction are driven in sequence from downstream in the first direction.

7. An ultra-fine bubble generating unit described in any one of claims 1 to 6, further having a common supply liquid chamber for supplying liquid to the supply ports of each of the multiple substrates.

8. The ultra-fine bubble generating unit according to any one of claims 1 to 7, wherein the first direction is a vertically upward direction.

9. The ultra-fine bubble generating unit according to any one of claims 1 to 8, a storage chamber for storing a liquid to be supplied to the ultra-fine bubble generating unit; An apparatus for producing ultra-fine bubble-containing liquid.

10. 10. The apparatus for producing ultra-fine bubble-containing liquid according to claim 9, wherein the liquid is circulatable between the storage chamber and the ultra-fine bubble generating unit.

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