Bubble generating device

Abstract

The invention relates to a bubble generating device. According to the invention, liquid fully containing bubbles can be generated. A bubble generating device (1) is provided with: a housing (2) in which a mixed fluid of a liquid and a gas supplied to the inside flows in an axial direction (X) from an inflow port (a liquid inflow port (211), a gas inflow port (212)) toward an outflow port (a fluid outflow port (2113)); a first member (5) supported by the housing inside the housing; and a second member (6) that is supported inside the housing by a shaft (3) extending in the axial direction and that rotates relative to the first member about the shaft, the second member (6) having blades (612) extending in the radial direction from the shaft and overlapping the first member in the axial and radial directions.

Description

Technical Field

[0001] The technology disclosed herein relates to a bubble generating device. Background Art

[0002] Liquids containing microbubbles are used in various facilities including wastewater treatment facilities. Various types of devices are known as devices for generating microbubbles. For example, Japanese Patent Gazette No. 2019-34292 describes an existing microbubble generating device that releases the attracted gas into the liquid while finely breaking it. Specifically, the existing microbubble generating device includes a disk immersed in the liquid and a hollow rotating shaft tube installed in the center of the disk. A plurality of hollow pipes are radially arranged and installed on the disk. If the disk rotates, the liquid flows into each hollow pipe by centrifugal force, and the gas is attracted to the hollow pipe from the hollow rotating shaft tube by the negative pressure when the liquid passes through the hollow pipe. The attracted gas is finely broken in each hollow pipe and released from the outer periphery of the disk into the liquid.

[0003] In addition, Japanese Patent Publication No. 2017-80721 describes an existing ultrafine bubble generating tool, which does not mix the sucked gas with the liquid, but generates microbubbles by dissolving the air in the liquid. Specifically, the existing generating tool has a cylindrical member, and the cylindrical member has a plurality of triangular prism-shaped protrusions. The cylindrical member rotates in the liquid with the axis as the center. As the cylindrical member rotates, turbulence is generated due to the protrusions, and the air contained in the liquid is extremely fined to generate ultrafine bubbles. Summary of the invention Problems to be solved by the invention

[0004] The micro-bubble generating device described in Japanese Patent Publication No. 2019-34292 utilizes the negative pressure generated by the rotation of the disk. Even if the rotation speed of the disk is increased, there is a limit to the amount of air that can be sucked in. The micro-bubble generating device described in the document is difficult to generate a liquid that fully contains micro-bubbles.

[0005] The ultrafine bubble generator described in Japanese Patent Publication No. 2017-80721 generates fine bubbles from air dissolved in a liquid. For example, for a liquid with little dissolved air such as wastewater, the generator cannot generate a sufficient amount of fine bubbles. In addition, the existing generator only rotates a cylindrical member immersed in a liquid, so a swirling flow is only generated around the cylindrical member, and thus a sufficient amount of fine bubbles may not be generated.

[0006] The techniques disclosed herein generate a liquid that substantially contains gas bubbles. Technical solutions to solve problems

[0007] The technology disclosed herein relates to a bubble generating device. The bubble generating device comprises: a housing in which a mixed fluid of a liquid and a gas supplied to the interior flows in an axial direction from an inlet toward an outlet; A first member supported by the housing in an interior of the housing; and A second member is supported by a shaft extending along the axial direction inside the housing and rotates relative to the first member around the shaft. The second member has blades extending from the shaft in a radial direction perpendicular to the axial direction and overlapping with the first member in the axial and radial directions.

[0008] In the bubble generating device, liquid and gas are supplied to the interior of the housing. The liquid and gas can be supplied to the interior of the housing separately, or a mixed fluid pre-mixed with the liquid and gas can be supplied to the interior of the housing. Inside the housing, the mixed fluid flows axially from the inlet toward the outlet.

[0009] The bubble generating device includes a first member. The first member is supported by a housing.

[0010] The bubble generating device comprises a second member. The second member is supported by an axially extending shaft inside the housing. The second member rotates relative to the first member around the shaft. The relative rotation of the first member and the second member can also be achieved as follows. That is, (1) the housing and the first member can be stationary, and the shaft and the second member can rotate; (2) the housing and the first member can rotate, and the shaft and the second member can be stationary; (3) the housing and the first member can rotate, and the shaft and the second member can rotate, for example, in opposite directions or in the same direction but at different rotation speeds.

[0011] The second member has blades. The blades overlap the first member in the axial and radial directions. As the second member rotates relative to each other, the mixed fluid is stirred between the blades and the first member, and bubbles are generated. Here, the bubbles generated by the bubble generating device may be micro bubbles, which include micro bubbles with an average diameter of less than 100 μm and 1 μm or more and ultra-fine bubbles with an average diameter of less than 1 μm. In addition, the bubbles generated by the bubble generating device may also be larger than micro bubbles, i.e., bubbles with an average diameter of more than 100 μm.

[0012] The relatively rotating blades also shear the mixed fluid containing bubbles in the circumferential direction and radial direction orthogonal to the axial direction and radial direction between the first member. The generated bubbles become finer. The combination of the relatively rotating first member and the second member can generate a sufficient amount of fine bubbles. Compared with the existing device, the bubble generating device can generate a liquid that fully contains bubbles.

[0013] Alternatively, the first member may include a plurality of protrusions, the protrusions protruding from the inner surface of the housing in the radial direction, and the plurality of protrusions being located at intervals in the axial direction. The second member is located between the protrusions.

[0014] This structure is conducive to increasing the shearing area between the first member and the second member, and increasing the amount of bubble generation. In addition, the plurality of protrusions of the first member arranged in the axial direction and the second member between the protrusions hinder the mixed fluid from flowing in the axial direction, and increase the shearing frequency of the mixed fluid flowing from the inlet to the outlet. The increase in the shearing frequency is also conducive to the generation of microbubbles and increases the amount of bubble generation.

[0015] The first member may include a second protrusion that is located between the protrusions in the axial direction, protrudes from the inner surface of the housing in the radial direction, and faces the second member.

[0016] By utilizing the centrifugal force generated by the relative rotation of the second member, the gas inside the housing has a tendency to be transported radially outward. The second protrusion that is radially opposite to the second member interferes with the gas and restricts the gas from flowing in the axial direction. The second protrusion retains the gas in the radial outer peripheral portion inside the housing. The retained bubbles become fine bubbles as the second member rotates relative to each other. The second protrusion contributes to an increase in the amount of bubbles generated by the bubble generating device.

[0017] The second protrusion may be continuous in the circumferential direction.

[0018] The second protrusions that are continuous in the circumferential direction effectively restrict the gas flow in the axial direction, thereby generating more fine bubbles.

[0019] A plurality of the protrusions may be arranged at intervals in the circumferential direction.

[0020] As the second member rotates relative to each other, a swirling flow centered on the axis is generated inside the housing. The plurality of protrusions arranged at intervals in the circumferential direction interfere with the swirling flow, increasing the shear frequency of the mixed fluid. The amount of bubbles generated further increases.

[0021] Alternatively, the first component may include: a rod-shaped member extending along the axial direction; and The annular member is an annular member extending in a circumferential direction along the inner surface of the housing, and is engaged with the rod-shaped member to position the rod-shaped member on the inner surface of the housing.

[0022] The combination of the rod-shaped member and the ring-shaped member is beneficial to realize the first member supported by the housing.

[0023] The second member may include a plurality of blades radially extending from the axis in the radial direction.

[0024] The plurality of blades that rotate relative to each other shear the mixed fluid between themselves and the first member, so that the bubbles become finer and the amount of bubbles generated increases. Effects of the Invention

[0025] As described above, the bubble generating device can generate liquid containing sufficient bubbles. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a perspective view of a bubble generating device. Figure 2 is an exploded view of the bubble generating device. Figure 3 : are the front view (left) and side view (right) of the first component. Figure 4 These are the front view and AA cross-sectional view of the rod-shaped member, and the front view and side view of the annular member and the impeller, respectively. Figure 5 It is the cross-sectional view (left) and BB sectional view (right) of the inside of the shell. Figure 6 1 and 2 are a transverse sectional view (left figure) and a CC sectional view (right figure) of the interior of a casing according to a modification example. Figure 7 1 and 2 are a cross-sectional view (left figure) and a DD cross-sectional view (right figure) of the interior of a casing according to a modification. Figure 8 1 and 2 are a front view of a rod-shaped member according to a modification, and a side view and an EE cross-sectional view of a ring-shaped member. Fig. 9 1 and 2 are a cross-sectional view (left figure) and an FF cross-sectional view (right figure) of the interior of a casing according to a modification example. Fig.10 It is a side view of the second member involved in a modification. Fig.11 1 and 2 are a cross-sectional view (left figure) and a GG cross-sectional view (right figure) of the interior of a casing according to a modification. Fig.12 It is a perspective view of a bubble generating device according to a modification. Fig.13 It is a perspective view of a bubble generating device according to still another modification. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the bubble generating device will be described with reference to the drawings. The bubble generating device described here is an example.

[0028] (Overall Structure of Bubble Generating Device) Figure 1 The whole of the bubble generating device 1 is shown. The bubble generating device 1 generates bubbles in a liquid. The bubble generating device 1 is used for wastewater treatment in a wastewater treatment facility. Specifically, the bubble generating device 1 generates fine bubbles of air in the liquid to be treated. If fine bubbles are generated, the dissolved oxygen concentration in the liquid increases. In addition, when the liquid to be treated contains solid matter, the fine bubbles in the liquid adhere to the solid matter, thereby making the solid matter float and be recovered.

[0029] Here, the bubbles generated by the bubble generating device 1 may be fine bubbles, including micro bubbles having an average diameter of less than 100 μm and 1 μm or more and ultrafine bubbles having an average diameter of less than 1 μm. In addition, the bubbles generated by the bubble generating device 1 may be larger than fine bubbles, that is, bubbles having an average diameter of 100 μm or more.

[0030] Figure 2 1 is an exploded perspective view of the bubble generating device 1. The bubble generating device 1 includes a housing 2. The housing 2 accommodates a first member 5 and a second member 6 described later. The bubble generating device 1 is configured such that the first member 5 and the second member 6 rotate relative to each other in the housing 2, thereby stirring a mixed fluid of liquid and gas and mechanically making the generated bubbles fine.

[0031] The housing 2 has a cylinder 21. The cylinder 21 is a cylinder extending along the axis of the bubble generating device 1. The first end and the second end opposite to the first end of the cylinder 21 are open. Figure 2 The second end is near the front right of the middle paper. Figure 2 The end of the paper left in depth. In addition, the tube 21 can also be a half-cut structure in which two members divided along the center line are combined.

[0032] Here, in the following description, the direction in which the axis of the tube 21 extends is referred to as the axial direction X. Figure 1 and Figure 2 In FIG. 1 , the direction from the front right of the paper toward the back left of the paper is defined as the positive direction of the axial direction X. As described later, the positive direction of the axial direction X corresponds to the main flow direction of the fluid in the bubble generating device 1 .

[0033] The barrel 21 has a liquid inlet 211. The liquid inlet 211 is located on the outer peripheral surface of the first end of the barrel 21. The liquid inlet 211 is a tube connected to the inside of the barrel 21, and protrudes from the outer peripheral surface of the first end of the barrel 21 to the outside in the radial direction r. Here, the radial direction r is a direction orthogonal to the axial direction X, and the direction from the axis of the barrel 21 toward the outside is set as the positive direction of the radial direction r. A pump is connected to the liquid inlet 211, for example. The pump forces a liquid, such as water, to flow into the inside of the housing 2 through the liquid inlet 211.

[0034] The cylinder 21 also has a gas inlet 212. The gas inlet 212 is arranged side by side along the circumferential direction θ relative to the liquid inlet 211 on the outer peripheral surface of the first end of the cylinder 21. Here, the circumferential direction θ is a direction orthogonal to the axial direction X and the radial direction r, respectively, and the rotation direction of the prime mover 4 described later is set as the positive direction of the circumferential direction θ. The gas inlet 212 is a pipe connected to the interior of the cylinder 21, and protrudes from the outer peripheral surface of the first end of the cylinder 21 to the outside of the radial direction r. The gas inlet 212 is connected to a blower, for example. The blower forcibly causes gas, such as air, to flow into the interior of the housing 2 through the gas inlet 212.

[0035] The barrel 21 also has a fluid outflow port 213. The fluid outflow port 213 is located on the outer peripheral surface of the second end of the barrel 21. The fluid outflow port 213 is a tube connected to the interior of the barrel 21, and protrudes from the outer peripheral surface of the second end of the barrel 21 to the outside in the radial direction r. The fluid outflow port 213 opens downward at a portion that is lower than the center of the barrel 21. The fluid outflow port 213 allows the liquid containing fine bubbles to flow out from the interior of the shell 2. A pipe is connected to the fluid outflow port 213. Inside the shell 2, the mixed fluid mainly flows along the axial direction X from the first end of the barrel 21 toward the second end.

[0036] Here, since the fluid outlet 213 opens downward at the lower side of the cylinder 21, the fluid outlet 213 can flow out the liquid containing fine bubbles even if the inside of the cylinder 21 is not filled with the liquid containing fine bubbles. This structure can reduce the driving force of the prime mover 4 described later.

[0037] The housing 2 has a first cover 22. The first cover 22 blocks the opening of the first end of the cylinder 21 to make the housing 2 watertight. The first cover 22 also supports a first bearing 24. The first bearing 24 rotatably supports a first end 32 of the shaft 3 described later.

[0038] The housing 2 has a second cover 23. The second cover 23 is mounted on the opening of the second end of the cylinder 21. The second cover 23 has a through hole 231 extending in the axial direction X. The second end 33 of the shaft 3 passes through the second cover 23. The second cover 23 also supports a second bearing 25. The second bearing 25 supports the second end 33 of the shaft 3 in a rotatable manner. The second cover 23 also accommodates a seal 26 in the through hole 231. The seal 26 seals around the second end 33 of the shaft 3, thereby making the housing 2 watertight. The seal 26 is, for example, a mechanical seal. The seal 26 is not limited to a specific structure.

[0039] The bubble generating device 1 includes a shaft 3. The shaft 3 extends in the axial direction X. The shaft 3 is inserted into the cylinder 21 of the housing 2. The shaft 3 is coaxial with the cylinder 21. The shaft 3 has a support portion 31, and a first end portion 32 and a second end portion 33 extending from the end of the support portion 31 in the axial direction X. The support portion 31 supports the second member 6 described later. The first end portion 32 is supported by the first bearing 24. The second end portion 33 is supported by the second bearing 25. The shaft 3 is supported by the housing 2 in a rotatable manner. In other words, the shaft 3 can rotate relative to the housing 2.

[0040] The bubble generating device 1 includes a prime mover 4. The prime mover 4 is, for example, an electric motor. In addition, the prime mover 4 is not limited to an electric motor. An output shaft 41 of the prime mover 4 is coupled to the second end 33 of the shaft 3 inside the second cover 23. The prime mover 4 rotates the shaft 3. In addition, the prime mover 4 may also be coupled to the first end 32 of the shaft 3.

[0041] The bubble generating device 1 includes a first member 5. The first member 5 is supported by a housing 2. The bubble generating device 1 includes a second member 6. The second member 6 is supported by a shaft 3. If the shaft 3 rotates, the second member 6 rotates together with the shaft 3. The second member 6 rotates relative to the first member 5. The first member 5 and the second member 6 cooperate to generate bubbles inside the housing 2. The details of the structures of the first member 5 and the second member 6 will be described later.

[0042] (Structure of the First Component) Figure 3 The first member 5 is shown. The outer peripheral portion of the first member 5 in the radial direction r is Figure 3 The first member 5 is circular in shape in the side view shown in the right figure, and has a hole 50 extending in the axial direction X at the center of the radial direction r. The first member 5 is substantially cylindrical. The first member 5 is inserted into the interior of the cylinder 21 of the housing 2 (see also Figure 5 ). The first member 5 is supported by the cylinder 21. The shaft 3 is inserted into the hole 50 of the first member 5.

[0043] As described above, the first member 5 is supported by the housing 2. In addition, the first member 5 may be fixed relative to the housing 2. The first member 5 may not be fixed relative to the housing 2. If the first member 5 is not fixed to the housing 2, it is easy to replace the first member 5 when the first member 5 deteriorates, for example. In addition, even if the first member 5 is not fixed to the housing 2, due to the weight of the first member 5, the first member 5 will not rotate relative to the housing 2, or will not substantially rotate when the bubble generating device 1 is in operation.

[0044] The first member 5 is constituted by combining a rod-shaped member 51 and an annular member 52 . Figure 4 A rod-shaped member 51 and an annular member 52 are illustrated.

[0045] The rod-shaped member 51 extends in the axial direction X. The plurality of rod-shaped members 51 are arranged along the inner peripheral surface of the cylinder 21 at equal intervals in the circumferential direction θ.

[0046] The rod-shaped member 51 has a base 511 and a plurality of protrusions 512. The base 511 is a thin flat plate extending in the axial direction X. The base 511 is in contact with the inner peripheral surface 214 (see also FIG. 21 ) of the cylinder 21. Figure 5 ) abuts. A plurality of protrusions 512 protrude from the base 511 toward the inner side in the radial direction r. The protrusion length L1 of the protrusion 512 is sufficiently longer than the radial length L2 of the base 511. As described later, the protrusion length L1 of the protrusion 512 is set to the length of the protrusion 512 overlapping with the blade 612 of the second member 6 in the radial direction r (see also Figure 5 ).

[0047] The plurality of protrusions 512 are arranged at equal intervals in the axial direction X. The number of the protrusions 512 may be set to an appropriate number.

[0048] The base 511 has an engaging portion 513. The engaging portion 513 is located between adjacent protrusions 512 and protrusions 512 in the axial direction X. More precisely, the engaging portion 513 is not located at all positions between adjacent protrusions 512 and protrusions 512, but is located at positions every other position in the axial direction X. The engaging portion 513 is a recessed portion that is recessed from the end of the base 511 toward the outside in the radial direction r. The engaging portion 513 is engaged with the annular member 52.

[0049] The annular member 52 has an annular shape and extends in the circumferential direction along the inner circumferential surface 214 of the cylinder 21 of the housing 2 . The thickness T1 of the annular member 52 in the radial direction r is greater than the length L2 of the base 511 of the rod-shaped member 51 .

[0050] The annular member 52 has a groove 523. The groove 523 is recessed radially inward from the outer peripheral edge of the annular member 52. The groove 523 is located at positions spaced evenly apart in the circumferential direction θ in the annular member 52. The groove 523 is a portion that engages with the engagement portion 513 of the rod-shaped member 51 (see Figure 4 The number of the grooves 523 corresponds to the number of the rod-shaped members 51 constituting the first member 5.

[0051] like Figure 2 , Figure 3 or Figure 4 As shown, the annular member 52 is located on the inner side in the radial direction r with respect to the rod-shaped members 51 arranged at equal intervals in the circumferential direction θ. Figure 5The first member 5 and the second member 6 accommodated in the housing 2 are shown. The groove 523 of the annular member 52 is engaged with the engaging portion 513 of the rod-shaped member 51, so that the rod-shaped member 51 is sandwiched between the inner peripheral surface 214 of the cylinder 21 of the housing 2 and the annular member 52. The annular member 52 is engaged with a plurality of engaging portions 513 arranged in the axial direction X in the rod-shaped member 51. The annular members 52 are arranged at equal intervals in the axial direction X.

[0052] The protrusions 512 of the rod-shaped member 51 protrude from the inner peripheral surface 214 of the cylinder 21 toward the inner side in the radial direction r. Figure 3 As shown in the left figure of FIG. , the protrusions 512 are arranged at equal intervals in the axial direction X, and as shown in FIG. Figure 3 As shown in the right figure of , they are arranged at equal intervals in the circumferential direction θ.

[0053] The annular member 52 has a thickness T1 that is longer than the length L2 of the base 511. Figure 5 As shown in the right figure of , the annular member 52 is formed with a second protrusion 521 that protrudes further inward in the radial direction r than the base 511. The length (T1-L2) of the second protrusion 521 is shorter than the length (L1) of the protrusion 512. The second protrusion 521 is located between the protrusions 512 and 512 that are adjacent in the axial direction X. In addition, as mentioned above, the annular member 52 that is engaged with the engaging portion 513 of the base 511 is not located at all positions between the adjacent protrusions 512 and 512, so the second protrusions 521 are respectively located between the adjacent protrusions 512 and 512 in the axial direction X.

[0054] The combination of the rod-shaped member 51 and the ring-shaped member 52 is the first member 5 supported by the housing 2 , and this combination facilitates realization of the first member 5 having the plurality of protrusions 512 and the second protrusions 521 .

[0055] (Structure of the Second Component) Figure 2 The second member 6 is shown. Figure 3 As shown by the double-dashed line in the right figure of FIG. , the outer peripheral portion of the radial direction r of the second member 6 is substantially circular in the side view. The second member 6 is externally inserted into the shaft 3 and supported by the shaft 3. The second member 6 rotates around the axis of the bubble generating device 1 as the shaft 3 rotates.

[0056] like Figure 2 or Figure 5 As shown, the second member 6 has an impeller 61 and a spacer 62. The impeller 61 and the spacer 62 inserted outside the shaft 3 are alternately arranged in the axial direction X.

[0057] like Figure 4As shown, the impeller 61 has a hub 611 and a plurality of blades 612. The hub 611 has a through hole inserted into the support portion 31 of the shaft 3. Reference numeral 613 is a keyway. The impeller 61 rotates together with the shaft 3.

[0058] The blades 612 protrude radially from the hub 611 toward the outside in the radial direction r. The plurality of blades 612 are located at equal intervals in the circumferential direction θ. Figure 5 As shown, when the second component 6 is housed inside the shell 2, the radial length L3 of the blade 612 is set to be greater than the length that overlaps with the protrusion 512 of the rod-shaped component 51 of the first component 5 in the radial direction r, and less than the length that does not interfere with the annular component 52 of the first component 5, namely the second protrusion 521.

[0059] like Figure 2 or Figure 5 As shown in the right figure of FIG. 2 , the spacer 62 is disposed between the impellers 61 in the axial direction X. The spacer 62 is annular and is externally inserted into the support portion 31 of the shaft 3. The spacer 62 maintains a constant interval between the impellers 61 in the axial direction X. Figure 5 As shown, the impeller 61 overlaps with the protrusion 512 of the first member 5 in the axial direction X and is located between the protrusions 512 of the first member 5. The blades 612 of the impeller 61 are also opposed to the annular member 52 in the radial direction r at every other blade in the axial direction X.

[0060] As described above, the plurality of impellers 61 are mounted on the shaft 3. When the plurality of impellers 61 are mounted on the shaft 3, the blades 612 are located at the same circumferential θ position of the plurality of impellers 61 arranged along the axial direction X (see Figure 3 The two-dot chain line in the right figure). That is, the blades 612 are located at overlapping positions in the axial direction X relative to the plurality of impellers 61. In addition, the blades 612 may be located at different positions in the circumferential direction θ relative to the plurality of impellers 61. That is, when the second member 6 is observed from the first end of the second member 6 along the axial direction X, the blades 612 of the plurality of impellers 61 may also be located at mutually staggered positions. As described later, the mutually staggered configuration of the blades 612 restricts the flow of the mixed fluid in the axial direction X, which is conducive to the generation of fine bubbles due to the increase in shear frequency.

[0061] (Operation of the bubble generating device) The bubble generating device 1 receives a supply of liquid from a liquid inlet 211 and receives a supply of gas from a gas inlet 212. The prime mover 4 rotates the shaft 3. Inside the housing 2, the second member 6 rotates relative to the first member 5. With the relative rotation of the second member 6, the mixed fluid inside the housing 2 is stirred, and bubbles are generated.

[0062] The blades 612 of the second member 6 that rotates relatively shear the mixed fluid in the circumferential direction θ and the radial direction r between the blades 612 and the protrusions 512 of the first member 5. The generated bubbles become finer. The combination of the first member 5 and the second member 6 that rotate relatively can generate a sufficient amount of fine bubbles by shearing the mixed fluid. Compared with the conventional devices, the bubble generating device 1 can generate a liquid that contains sufficient bubbles. The liquid containing fine bubbles flows out from the inside of the housing 2 through the fluid outlet 213.

[0063] The first member 5 has a plurality of protrusions 512 spaced apart in the axial direction X, and the blades 612 of the second member 6 are located between the protrusions 512 and the protrusions 512. This structure increases the shear generation sites between the first member 5 and the second member 6, and increases the amount of bubbles generated. In addition, the plurality of protrusions 512 arranged in the axial direction X and the plurality of blades 612 arranged in the axial direction X hinder the mixed fluid from flowing in the axial direction X, and increase the shear frequency of the mixed fluid. The increase in the shear frequency also increases the amount of bubbles generated.

[0064] The protrusions 512 of the first member 5 are arranged at intervals in the circumferential direction θ. As the second member 6 rotates relative to each other, a swirling flow centered on the axis 3 is generated inside the housing 2. The plurality of protrusions 512 arranged at intervals in the circumferential direction θ interfere with the swirling flow, thereby increasing the shear frequency of the mixed fluid. The amount of bubble generation is further increased.

[0065] In addition, the second member 6 also has a plurality of blades 612 arranged at intervals in the circumferential direction θ. The plurality of blades 612 that rotate relatively shear the mixed fluid between themselves and the protrusions 512. The amount of bubbles generated increases.

[0066] The first member 5 further includes a second protrusion 521. The second protrusion 521 is located between the protrusions 512, protrudes from the inner peripheral surface 214 of the housing 2 in the radial direction r, and faces the blades 612 of the second member 6. Due to the centrifugal force generated by the relative rotation of the second member 6, the gas inside the housing 2 tends to be transported to the outside in the radial direction r (see Figure 5 The second protrusion 521 opposite to the blade 612 in the radial direction r interferes with the gas and restricts the gas from flowing in the axial direction X. The second protrusion 521 retains the gas at the outer peripheral portion in the radial direction r inside the housing 2. The retained gas becomes fine bubbles as the second member 6 rotates relative to each other. The second protrusion 521 contributes to an increase in the amount of bubbles generated by the bubble generating device 1.

[0067] In addition, if Figure 5 As shown in the left figure of FIG. , the second protrusions 521 are continuous in the circumferential direction θ. The second protrusions 521 that are continuous in the circumferential direction θ effectively restrict the flow of gas in the axial direction X. Since the gas is retained in the outer peripheral portion in the radial direction r, more fine bubbles are generated.

[0068] Compared with the conventional bubble generating device, the bubble generating device 1 has a feature of a larger flow path. The bubble generating device 1 having a larger flow path has the advantage of being able to directly treat turbid water and is suitable for use as a bubble generating device for wastewater treatment. In addition, if activated carbon powder is added to the interior of the housing 2, the activated carbon effect such as reduction of COD (Chemical Oxygen Demand) and decolorization of wastewater is improved.

[0069] The bubble generating device 1 can also generate ozone water by generating fine bubbles of ozone. Ozone water can be used, for example, for purification of closed water areas. In addition, by utilizing the high oxidizing power of ozone water, the ozone water generated by the bubble generating device 1 can also be used for cleaning, deodorization or decolorization. The bubble generating device 1 can seal the supplied gas inside the housing 2. The bubble generating device 1 can suppress the leakage of ozone into the atmosphere, can ensure high safety, and can efficiently dissolve expensive ozone gas in water.

[0070] In addition, the use of the air bubble generating device 1 is not limited to wastewater treatment. The use of the air bubble generating device 1 is various.

[0071] (Variant 1) Figure 6 Modification examples of the second protrusion are shown. Figure 6 The second protrusions 522 of the illustrated first member 5 are not continuous in the circumferential direction θ, but a plurality of second protrusions 522 are arranged at intervals in the circumferential direction θ.

[0072] The plurality of second protrusions 522 arranged at intervals in the circumferential direction θ interfere with the swirling flow inside the housing 2. This increases the amount of bubbles generated.

[0073] In addition, if Figure 6 As shown in the left figure, in the first member 5, the second protrusion 522 is offset from the protrusion 512 in the circumferential direction θ. The protrusion 512 and the second protrusion 522 offset in the circumferential direction θ hinder the flow of the mixed fluid in the axial direction X. As mentioned above, the shear frequency of the mixed fluid increases, and the amount of bubble generation increases.

[0074] In addition, the second protrusion 522 and the protrusion 512 may be located at the same position in the circumferential direction θ.

[0075] (Variant 2) Figure 7 Modifications of the annular member are shown. Figure 7 The thickness T2 of the annular member 53 of the first member 5 in the radial direction r is greater than Figure 5The thickness T1 of the annular member 52 shown in FIG. 1 is thin. The thickness T2 is equal to the length L2 of the base 511 of the rod-shaped member 51. The annular member 53 forms a second protrusion 531 protruding inward in the radial direction r from the inner peripheral surface 214 of the tube 21 of the housing 2.

[0076] The second protrusion 531 can also retain gas in the outer peripheral portion in the radial direction r inside the housing 2, similarly to the second protrusion 521 and the second protrusion 522. The retained gas becomes fine bubbles as the second member 6 rotates relative to each other, so Figure 7 The second protrusion 531 also contributes to increasing the amount of bubbles generated by the bubble generating device 1 .

[0077] In addition, Figure 7 In the bubble generating device 1 , the length L3 of the blade 612 of the second member 6 can be longer than that of the illustrated example within a limit that the blade 612 does not interfere with the annular member 53 .

[0078] (Variant 3) Figure 8 Modifications of the first member are shown. Figure 8 The protrusion 541 of the first member 5 is continuous in the circumferential direction θ. Fig. 9 This modification example is Figure 5 The corresponding figure.

[0079] In more detail, Figure 3 , Figure 4 and Figure 5 In the embodiment, the protrusion 512 of the first member 5 is formed by the rod-shaped member 51. In contrast, Figure 8 The protrusion 541 of the first member 5 is formed by the annular member 54. The annular member 54 and Figure 4 Compared with the annular member 52, the thickness T3 in the radial direction r is thicker (T3>T1). Fig. 9 As shown, the thickness T3 is set to a length that overlaps with the blades 612 of the second member 6 in the radial direction r inside the housing 2 .

[0080] The rod-shaped member 55 of the first member 5 has no protrusions and only a base. The rod-shaped member 55 has a snap-fitting portion 551. The snap-fitting portion 551 is located at Figure 4 The engagement portion 551 is engaged with the groove 543 of the annular member 54. The groove 543 is recessed from the outer peripheral edge of the annular member 54 toward the inner side in the radial direction. Figure 8 and Fig. 9 The number of annular members 54 is greater than Figure 5 The number of the annular members 52 is large.

[0081] like Fig. 9As shown, the blade 612 of the second member 6 is located between the annular members 54 and the annular members 54 adjacent in the axial direction X. Between the annular members 54 and the annular members 54, a second protrusion 552 is formed at a portion of the rod-shaped member 55 that is opposite to the blade 612 in the radial direction r and protrudes further inward in the radial direction r than the inner peripheral surface 214 of the cylinder 21 of the housing 2.

[0082] The protrusions 541 that are continuous in the circumferential direction θ interfere with the flow of the mixed fluid in the axial direction X, and increase the shear frequency of the mixed fluid accompanying the relative rotation of the second member 6. The amount of generated bubbles further increases.

[0083] (Variant 4) Fig.10 Modifications of the impeller are shown. Fig.10 The blades 632 of the impeller 63 are continuous in the circumferential direction θ. Fig.11 This modification example is related to Figure 5 The corresponding figure.

[0084] The blades 632 extend outward in the radial direction r from the hub 631 over the entire circumference of the impeller 63. The impeller 63 has a disk shape as a whole.

[0085] The blades 632 that are continuous in the circumferential direction interfere with the flow of the mixed fluid in the axial direction X, and increase the shear frequency of the mixed fluid accompanying the relative rotation of the second member 6. The amount of generated bubbles further increases.

[0086] In addition, the structural features of the above-mentioned embodiment and Modifications 1 to 4 can also be combined with each other within a possible range.

[0087] (Variant 5) Fig.12 2 shows a modified example of the outflow port. In addition to the fluid outflow port 213, the housing 2 may also have a gas outflow port 215. The gas outflow port 215 is located on the outer peripheral surface of the second end of the cylinder 21. The gas outflow port 215 protrudes from the outer peripheral surface of the second end of the cylinder 21 to the outside in the radial direction r. The gas outflow port 215 opens upward at the upper part of the cylinder 21.

[0088] As described above, the fluid outlet 213 located at the lower part allows the liquid containing fine bubbles to flow out. The gas outlet 215 located at the upper part mainly allows the gas accumulated in the upper part of the cylinder 21 to flow out. The gas flowing out of the gas outlet 215 can also flow into the cylinder 21 again from the gas inlet 212. When the bubble generating device 1 is used for the generation of ozone water, for example, in addition to ensuring safety by sealing, ozone gas can also be efficiently dissolved in the liquid.

[0089] (Variant 6) Fig.13A modification of the outflow port is shown. Since the gas generating device 1 generates fine bubbles, it has a characteristic that the bubbles in the liquid have a long dissolution time. Therefore, the bubble generating device 1 may also include a tank 7 for the liquid containing fine bubbles. The dissolved state of the fine bubbles is maintained during the storage in the tank 7. By storing the liquid containing fine bubbles in the tank 7, it is possible to cope with the increase or decrease in demand. As described later, the outflow port 216 and the outflow port 217 are connected to the tank 7.

[0090] The tank 7 is formed by the lower portion of the cylinder 21, the partition member 70, the side wall 71 and the support platform 72. Fig.13 In the example, the partition member 70 is a member having a U-shaped cross section, and Fig.13 As shown by the two-dot chain line, the partition member 70 is fixed to the lower side of the cylinder 21 between the side wall 71 and the support platform 72. In addition, the side wall 71 is fixed to the first end of the cylinder 21 and extends downward. The support platform 72 supports the cylinder 21 and the prime mover 4.

[0091] A communication hole 218 is formed at the lower portion of the outer peripheral surface at the second end of the cylinder 21. The communication hole 218 allows the interior of the cylinder 21 to communicate with the interior of the tank 7. The liquid containing fine bubbles generated in the cylinder 21 is sent to the tank 7 through the communication hole 218. The communication hole 218 is an example of an outflow port. The tank 7 stores the liquid containing fine bubbles.

[0092] The outflow port 216 is a fluid outflow port 216 , and the outflow port 217 is a gas outflow port 217 . The fluid outflow port 216 and the gas outflow port 217 are respectively attached to the side wall 71 of the tank 7 .

[0093] The fluid outflow port 216 allows the liquid containing fine bubbles to flow out from the inside of the tank 7. The fluid outflow port 216 is installed at the lower part of the side wall 71. The fluid outflow port 216 installed at the lower part of the side wall 71 can allow the liquid containing fine bubbles to flow out even if the tank 7 is not filled with the liquid containing fine bubbles.

[0094] The gas outlet 217 allows the gas separated inside the tank 7 to flow out of the tank 7. The gas outlet 217 is installed at the upper part of the side wall 71. The gas outlet 217 installed at the upper part can allow the gas accumulated in the upper part of the tank 7 to flow out. The gas outlet 217 may also be connected to the gas inlet 212.

[0095] (Other Modifications) The bubble generating device 1 has a liquid inlet 211 and a gas inlet 212, and liquid and gas are supplied separately into the housing 2. Alternatively, a mixed fluid in which liquid and gas are mixed in advance may be supplied into the housing 2.

[0096] In the bubble generating device 1, the housing 2 and the first member 5 are stationary, and the shaft 3 and the second member 6 rotate. However, the housing 2 and the first member 5 may rotate, and the shaft 3 and the second member 6 may be stationary. In addition, the housing 2 and the first member 5 may rotate, and the shaft 3 and the second member 6 may rotate, for example, in opposite directions. Alternatively, the housing 2 and the first member 5 may rotate, and the shaft 3 and the second member 6 may rotate in the same direction as the housing 2 and the first member 5 but at a different speed. Explanation of symbols

[0097] 1. Bubble generating device 2 Shell 211 Liquid inlet 212 Gas flow inlet 213 fluid outlet 214 inner surface 215 Gas outlet 216 fluid outlet 217 Gas outlet 218 communication hole (outlet) 3-axis 5. First Component 51 Rod-shaped member 512 protrusion 52 Ring member 521 Second protrusion 522 Second protrusion 53 Ring member 531 Second protrusion 54 Ring member 541 protrusion 55 Rod-shaped member 552 Second protrusion 6 Second component 612 blades 632 blades.

Claims

1. A bubble generating device, comprising: a housing in which a mixed fluid of a liquid and a gas supplied to the interior flows in an axial direction from an inlet toward an outlet; A first member supported by the housing in an interior of the housing; and A second member is supported by a shaft extending along the axial direction inside the housing and rotates relative to the first member around the shaft. The second member has blades extending from the shaft in a radial direction perpendicular to the axial direction and overlapping with the first member in the axial and radial directions.

2. The bubble generating device according to claim 1, wherein: The first member has a plurality of protrusions, the protrusions protruding from the inner surface of the housing in the radial direction, and the plurality of protrusions are located at intervals in the axial direction. The second member is located between the protrusions.

3. The bubble generating device according to claim 2, wherein: The first member has a second protrusion that is located between the protrusions in the axial direction, protrudes from the inner surface of the housing in the radial direction, and faces the second member.

4. The bubble generating device according to claim 3, wherein: The second protrusion is continuous in the circumferential direction.

5. The bubble generating device according to claim 2, wherein: A plurality of the protrusions are arranged at intervals in the circumferential direction.

6. The bubble generating device according to claim 1, wherein: The first component comprises: a rod-shaped member extending along the axial direction; and The annular member is an annular member extending in a circumferential direction along the inner surface of the housing, and is engaged with the rod-shaped member to position the rod-shaped member on the inner surface of the housing.

7. The bubble generating device according to claim 1, wherein: The second member has a plurality of blades radially extending from the axis in the radial direction.

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