Air bubble generation device

Abstract

To improve air bubble generation efficiency in an air bubble generation part in an air bubble generation device including the air bubble generation part that generates minute air bubbles in a water flow passing the inside of a cylindrical body part.SOLUTION: Provided is an air bubble generation device including a body part and an air bubble generation part arranged in the inside of the body part. The air bubble generation part includes a cylindrical base part and a column part arranged in an outer periphery of the base part. The base part includes a water flow hole having a diameter reduced in a downstream side. A rear surface of the base part and a rear surface of the column part erect in a peripheral direction in a matching manner at an outlet of the water flow hole. The rear surface of the column part has a recess formed thereon.SELECTED DRAWING: Figure 22

Description

[Technical field]

[0001] The present invention relates to an air bubble generating device that generates nano-order microbubbles in water. [Background technology]

[0002] One method for forming microbubbles is to utilize the cavitation effect. Patent Document 1 discloses an air bubble generator in which multiple screws (columnar parts) protrude into an orifice in a tubular main body, generating microbubbles in the water flow passing through the orifice. When tap water is introduced into this bubble generator, the water flow is throttled by the throttle section formed between the opposing screws, increasing the flow rate. As a result, a negative pressure area is formed downstream of the throttle section according to Bernoulli's principle, and the cavitation (pressure reduction) effect causes dissolved gas in the water to separate out, generating tiny bubbles. Please also refer to Patent Documents 2 and 3 which disclose inventions related to this case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5712292 [Patent Document 2] JP 2008-18330 A [Patent Document 3] Patent No. 6077627 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, there has been a demand for air bubble generators with higher microbubble generation efficiency. Therefore, one object of the present invention is to improve the bubble generation efficiency of an air bubble generator having a bubble generating unit in a tubular main body that generates microbubbles in a water flow passing through the inside of the main body. [Means for solving the problem]

[0005] As a result of intensive research into achieving the above object, the inventors of the present invention have come up with an air bubble generating device according to a first aspect of the present invention, which has the following configuration: That is, the air bubble generating device includes a cylindrical main body and an air bubble generating unit disposed within the main body, The bubble generating section has slits extending radially from a center point in the main body section in a cross section of the main body section, a pillar portion that bulges out from an inner peripheral surface of the main body portion and forms a periphery of the slit, The amount of bulging of the pillar portion gradually decreases from the periphery of the slit toward the upstream side, and a recess is formed on the downstream side surface of the pillar portion. Bubble generator.

[0006] According to the air bubble generator of the first aspect thus defined, the amount of expansion of the columnar portion gradually decreases from the periphery of the slit toward the upstream side, in other words, the columnar portion gradually expands when viewed from the upstream side, so that the flow path in the main body portion is narrowed and the water flow in the main body portion increases in speed while being compressed. As a result of the water flow passing through the slit, a negative pressure area is formed on the downstream side of the slit. Furthermore, since a recess is formed on the downstream side of the pillar, the water flow that passes through the slit and turns around to the downstream side is sucked into the recess and its flow speed increases, generating negative pressure here as well. With the air bubble generating section configured in this manner, a negative pressure area is formed on the downstream side of the slit, and also around the recess on the downstream side of the column, thereby generating a sufficient amount of minute air bubbles. In addition, the slits of the bubble generating section are defined by a column that bulges out from the main body, i.e., is formed integrally with the main body, so the main body and column are molded as a single unit. Here, the column gradually bulges out from its downstream side toward the upstream side, so the mold can be pulled out toward the upstream side. Similarly, the downstream side only has a recess, so the mold can be pulled out toward the downstream side. In other words, this bubble generating device can be made into a resin molded product by using a mold that splits in the radial direction at the main body.

[0007] A second aspect of the present invention is defined as follows: In the air bubble generating device defined in the first aspect, the center is located on the central axis of the main body. According to the bubble generating device of the second aspect thus defined, the radial center of the radially spreading slits coincides with the center of the main body. As a result, the slits are formed radially from the center in one imaginary cross section of the main body. Therefore, the slits are evenly distributed within the main body. This makes it easier for water to flow within the main body, resulting in a faster flow rate. The faster the flow rate, the more bubbles can be generated.

[0008] A third aspect of the present invention is defined as follows: That is, in the air bubble generator according to the first or second aspect, the cross-sectional area of ​​the columnar portion is gradually reduced toward the upstream side with a surface defined by the edges of adjacent slits as the downstream side, and the cross-sectional area becomes substantially zero at the upstream end of the main body portion. The shape of the column portion in the bubble generator of the third aspect thus defined is described more specifically. The cross-sectional area of ​​the column portion at the upstream end of the main body portion is substantially zero, i.e., the column portion starts to rise from the upstream end of the main body portion, thereby minimizing the resistance of the column portion to the water flow and maximizing the flow rate of the water flow in the main body portion.

[0009] A fourth aspect of the present invention is defined as follows: In the air bubble generating device defined in the first or second aspect, the columnar portion is cone-shaped with a surface defined by the edges of the adjacent slits as a base, and a ridgeline of the columnar portion connects an intersection point of the edges of the adjacent slits and a point on the inner circumferential surface of the main body portion where imaginary bisectors of the edges intersect. In the air bubble generator of the fourth aspect thus defined, the shape of the column part is described more specifically. That is, by defining the column part as a cone shape and the ridge line of the column part being connected to the inner circumferential surface of the main body part, i.e., the ridge line starting to rise from the inner circumferential surface of the main body part, the water flow resistance of the column part can be made as small as possible.

[0010] A fifth aspect of the present invention is defined as follows: That is, in the air bubble generation device defined in any one of the first to fourth aspects, the recesses formed on the downstream side surface of the column portion are arranged radially from the center. According to the air bubble generation device of the fifth aspect thus defined, the recesses are evenly distributed in the imaginary cross section of the main body defining the downstream side surface of the column, so that the air bubbles resulting from the recesses are also evenly generated.

[0011] A sixth aspect of the present invention is defined as follows: In the air bubble generation device defined in any one of the first to fifth aspects, the recess passes through an inner circumferential surface of the main body to form a gap in a peripheral wall of the main body. According to the air bubble generation device of the sixth aspect thus defined, the recess communicates with the gap formed in the peripheral wall, so that the water flow is easily drawn into the recess, thereby facilitating the generation of negative pressure. The gap formed in the peripheral wall of the main body may be formed inside the peripheral wall, or may be formed between the peripheral wall and another component with which the peripheral wall abuts.

[0012] A seventh aspect of the present invention is defined as follows: A bubble generating unit comprising at least one bubble generating device defined in any one of the first to sixth aspects, and a housing having an orifice and housing the bubble generating device in a small diameter portion thereof, A bubble generating unit, wherein a main body of the bubble generating device is embedded in the housing, and the column portion is exposed to the small diameter portion of the orifice. As mentioned above, the air bubble generator can be molded, in other words, the air bubble generator itself can be manufactured at low cost by standardizing the specifications. By arbitrarily designing the housing of the air bubble generator, it becomes possible to apply the air bubble generator to various water flow sources. For example, when a bubble generating unit incorporating one bubble generator is applied to a water flow (0.15 MPa to 0.75 MPa) supplied from a water supply pipe, microbubbles can be generated without pressurizing with a pump, etc. In this case, it is preferable that the opening diameter of the housing is 10 to 30 mm, and its outer diameter is also equal to the outer diameter of the water supply pipe. When applied to a water flow supplied from a water tap, the diameter of the upstream end of the inner circumferential surface of the main body of the air bubble generator (the region where the columnar portion is substantially absent) is preferably 5.0 to 10.0 mm. The width of the slits is 0.1 to 3 mm, and each slit is formed evenly and radially from the center of the main body. The number of slits is preferably 4 to 10. The slits are preferably formed so as to be in contact with the inner circumferential surface of the main body, but may be formed partway along the inner circumferential surface as viewed from the center. When using a pressurized water flow, it is preferable to incorporate multiple air bubble generators in series in a housing. In this case, it is preferable to overlap the slits of each air bubble generator in the water flow direction, i.e., in the axial direction of the housing. This is to ensure a flow velocity when passing through the slits. According to the study by the present inventors, it is preferable to set the flow velocity when passing through the slits to 100 m / sec or more.

[0013] An eighth aspect of the present invention is defined as follows: In the air bubble generating unit defined in the seventh aspect, the housing part is divided perpendicular to the axis at the small diameter part, and the main body part of the air bubble generating device is sandwiched between the divided pieces. According to the air bubble generating unit of the eighth aspect defined above, the air bubble generating device can be easily attached to the housing, and therefore an inexpensive air bubble generating unit can be provided.

[0014] A ninth aspect of the present invention is defined as follows: In the air bubble generating unit defined in the seventh aspect, one of the divided pieces and the air bubble generating means are integrally molded. Since the air bubble generating device can be molded, if the divided pieces of the housing part are similarly designed to be moldable, the air bubble generating device can be integrated into the divided pieces and molded. Therefore, by integrally molding one of the divided pieces and the air bubble generating device as defined in the ninth aspect, the number of parts of the air bubble generating unit can be reduced, and thus the manufacturing cost can be reduced.

[0015] A tenth aspect of the present invention is defined as follows: A bubble generating device comprising a cylindrical main body and a bubble generating unit disposed within the main body, The bubble generating section includes a plurality of pillars protruding from an inner circumferential surface of the main body, The column portion has a structure formed by splitting a triangular pyramid in two, the bottom surface of the column portion coincides with the downstream side surface of the main body portion, the top surface of the column portion coincides with the upstream side surface of the main body portion, and the ridge line of the column portion is disposed toward the central axis of the main body portion, A bubble generating device in which a slit is formed between the edges of the bottom surface of the column. According to the air bubble generator defined in the tenth aspect thus defined, the columnar shape is a triangular pyramid, thereby minimizing the water flow resistance, and thus a sufficient negative pressure area is formed downstream of the slit.

[0016] An eleventh aspect of the present invention is defined as follows: That is, in the air bubble generating device defined in the tenth aspect, a recess is formed in the bottom surface of the column. According to the air bubble generation device of the eleventh aspect thus defined, a recess is formed in the bottom surface, and therefore a negative pressure area is also formed in the recess, thereby improving the efficiency of air bubble generation. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a plan view of an air bubble generating device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 3 is a perspective view showing the structure of an air bubble generating unit incorporating the air bubble generating device of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line BB in FIG. [Diagram 5] FIG. 5 is an exploded perspective view of the bubble generating unit. [Figure 6] FIG. 6 is an exploded perspective view showing the structure of an air bubble generation unit incorporating two air bubble generation devices according to the first embodiment. [Figure 7] FIG. 7 is a perspective view showing the structure of the bubble generating unit. [Figure 8] FIG. 8 is a cross-sectional view taken along line CC in FIG. [Figure 9]FIG. 9 is a plan view of another embodiment of the air bubble generating device. [Figure 10] FIG. 10 is a cross-sectional view taken along line DD in FIG. [Figure 11] FIG. 11 shows a structure in which two of the bubble generating devices shown in FIG. 9 are connected together. [Figure 12] FIG. 12 is a cross-sectional view taken along line EE in FIG. [Figure 13] FIG. 13 is a graph showing the change in the amount of dissolved oxygen over time. [Figure 14] FIGS. 14(A) to (C) show cross-sectional views of a pillar part of an air bubble generation device according to a second embodiment of the present invention. [Figure 15] FIG. 15(A) to (C) show similar cross-sectional views of other pillar parts. [Figure 16] FIG. 16(A) to (D) show cross-sectional views of other pillar portions. [Figure 17] Figure 17 shows the distribution of negative pressure areas when the column is tilted relative to the water flow. [Figure 18] FIG. 18 shows the structure of an air bubble generating device according to an embodiment of the present invention, in which FIG. 5(A) is a side view seen from the downstream side, and FIG. 5(B) is a vertical sectional view. [Figure 19] FIG. 19 is a side view seen from the downstream side, showing the structure of an air bubble generation device according to another embodiment of the present invention. [Figure 20] FIG. 20 is a side view seen from the downstream side, showing the structure of an air bubble generation device according to another embodiment of the present invention. [Figure 21] FIG. 21 is a vertical sectional view showing the structure of an air bubble generating device according to an embodiment of the present invention. [Figure 22] FIG. 22 is a perspective view of the bubble generating section. [Figure 23] FIG. 23 is a plan view of the bubble generating section. [Figure 24] FIG. 24 is a cross-sectional view taken along the line AA in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Embodiment 1) A plan view of an air bubble generation device 1000 according to a first embodiment of the present invention is shown in Fig. 1. A cross-sectional view of the same is shown in Fig. 2. The air bubble generating device 1000 comprises a main body 1100 and an air bubble generating unit 1200 . The main body 1100 is formed in a cylindrical shape. A part of the outer circumferential surface of the main body 1100 is cut out to form a flat portion 1110. This flat portion prevents unnecessary rotation and is used for positioning. The main body 1100 does not have to be cylindrical, and any shape can be adopted. For example, it can be a square tube. It can also be divided in the radial direction. It can also be tapered, with the diameter decreasing on the downstream side in the water flow direction.

[0019] The bubble generation part 1200 includes a pillar part 1210 that bulges out from the inner peripheral surface of the main body part 1100 and is formed integrally with the main body part 1100. In this example, there are six pillar parts 1210. Six slits 1300 are formed by the periphery of the downstream side surface (the lower side surface in FIG. 2) of each pillar part 1210. The slits 1300 are formed radially in a plan view. In this example, the center of radiation coincides with the central axis of the main body 1100. The center of radiation does not have to coincide with the central axis of the main body 1100. The slits 1300 are formed on one imaginary cross section in the main body 1100. In other words, in each column 1210, the portion that bulges most from the inner peripheral surface of the main body 1100 is formed on the imaginary cross section. It is preferable that this most bulging portion coincides with the periphery of the bottom surface 1211 of the column 1210. It is preferable that the bottom surface 1211 is formed at a right angle or at an acute angle to the water flow direction at the most bulging portion, because this can cause a large change in the flow rate and generate negative pressure there.

[0020] A recess 1220 is formed in the bottom surface 1211. The water flow that has flowed over the slit 1300 and into the bottom surface side is further sucked into this recess 1220, so that the generation of negative pressure on the bottom surface 1211 is promoted. In order to generate negative pressure evenly, it is preferable that the recesses 1220 are arranged radially and evenly from the center of the slit 1300, that is, from the central axis of the main body portion 1100. The recess 1220 extends to the main body 1100. The portion of the main body 1100 where the recess 1220 exists becomes a gap during use. Water attempting to flow into the recess 1220 will interfere with the water already present in the recess 1220, but this gap mitigates this interference. This increases the negative pressure generation effect. In this example, each slit 1300 is formed to have the same width, but the width can be varied. The width can be varied in this case either by making each slit have a different width or by varying the width of a single slit.

[0021] The cross-sectional area of ​​the column 1210 gradually decreases from its bottom surface 1211 toward the upstream side. Then, the cross-sectional area becomes zero at the upstream side. This reduces the resistance of the column to the water flow. Also, by adopting such a structure, the mold can be pulled out without any resistance during molding. The pillar portion 1210 in this example has a cone shape with a surface defined by each edge 1310 of the slit 1300 as the bottom surface 1211. The ridge line 1215 of the pillar portion 1210 is defined as follows: it is a line connecting the intersection point of the edges 1310, 1310 of adjacent slits 1300 and the most upstream point of the inner circumferential surface of the main body portion 1100 where the imaginary bisecting plane of the edges 1310, 1310 intersect.

[0022] In this example, the bottom surface 1211 of the pillar portion 1210 coincides with the downstream side surface 1113 of the main body portion 1100, and the upstream end of the pillar portion 1210 coincides with the upstream side surface 1115 of the main body portion 1100. The two do not necessarily need to coincide. For example, the length of the main body portion 1100 in the water flow direction can be longer than that of the pillar portion 1210. In this example, each post 1210 has the same shape, however, the shape of the posts can vary.

[0023] 3 to 5 show an example of an air bubble generating unit 2000 incorporating the air bubble generating device 1000 described above. The air bubble generating unit 2000 is composed of an air bubble generating device 1000 and a housing part 2100 . The casing 2100 is made up of an upstream piece 2200 and a downstream piece 2300. When the two are connected together, an orifice 2110 is formed on the inner periphery of the casing 2100, as shown in FIG.

[0024] Storage recesses 2210, 2310 are formed on the opposing surfaces of the upstream piece 2200 and the downstream piece 2300. The main body 1100 of the air bubble generation device 1000 is stored in the space formed by the storage recesses 2210, 2310. The diameter of the inner circumferential surface of the orifice 2110 is the same as the diameter of the inner circumferential surface of the main body 1100. This is to minimize the water flow resistance. The recess 1220 formed in the bottom surface 1211 of the bubble generation unit 1200 is configured to cut into the housing unit 2100. An air pocket (void) is formed in the portion cut into the housing unit 2100. This air pocket makes it easier for the water flow to be sucked into the recess 1220, promoting the generation of negative pressure.

[0025] The structure of the housing part is designed as desired depending on the application of the air bubble generating unit 2000. The upstream piece 2200, the downstream piece 2300 and the air bubble generating device 1000 are joined liquid-tightly by adhesive or high-frequency fusion. These members are preferably made of the same or similar resin material. In this example, the upstream piece 2200, the downstream piece 2300, and the air bubble generator 1000 are separate, but the air bubble generator 1000 and the upstream piece 2200 or the downstream piece 2300 may be integrated together. In order to make the recess 1220 bite into the housing part 2100, it is preferable to integrate the air bubble generator 1000 and the upstream piece 2200.

[0026] 6 to 8 show an air bubble generation unit 3000 in which two air bubble generation devices 1000 are connected in the axial direction. The same elements as those in the example of Figs. 1 to 5 are given the same reference numerals and their explanation is partially omitted. Three or more air bubble generation devices 1000 can also be connected. This air bubble generating unit 3000 is composed of two air bubble generating devices 1000 and a housing part 3100. The casing 3100 is made up of an upstream piece 3200 and a downstream piece 3300. When the two are connected together, an orifice 3110 is formed on the inner periphery of the casing 3100, as shown in FIG. Storage recesses 3210, 3310 are formed on the opposing surfaces of the upstream piece 3200 and the downstream piece 3300. The main body 1100 of the air bubble generation device 1000 is stored in the space formed by the storage recesses 3210, 3310.

[0027] Figures 9 and 10 show another example of an air bubble generator 1500. The same elements as those in the example of Figures 1 and 2 are given the same reference numerals and their explanation will be partially omitted. This air bubble generator 1500 has eight slits 1300. Because the number of slits 1300 is increased, the width of the eight pillars 1710 is narrower. Also, in this example, the ridges 1715 of the pillars 1710 are bent. That is, they are displaced toward one edge 1310 from the plane that bisects the edges 1310, 1310 of the adjacent slits. This creates a change (vortex) in the water flow in the air bubble generator 170, allowing the water to pass through it more smoothly. This air bubble generating device 1500 can be inserted into the housing unit 2100 shown in FIG.

[0028] 11 and 12 show an example of connecting two air bubble generators 1500. It is also possible to connect three or more air bubble generators. In this example, connecting protrusions 1501 and engagement recesses 1503 are provided on the top and bottom surfaces of the main body 1100 of the air bubble generator 1500. The air bubble generation devices 1500, 1500 assembled in this manner can be inserted into the housing unit 3100 shown in FIG.

[0029] The air bubble generating unit described in the first embodiment is designed to be incorporated in, for example, a shower head. Therefore, a sufficient amount of microbubbles is generated by passing water at a pressure of 0.15 to 0.75 MPa through the air bubble generating device 1000, 1500 just once.

[0030] The following describes the embodiments. The bubble generating unit 2000 shown in FIG. 4, that is, one using one bubble generating device 1000, was connected to a household water supply by a commercially available hose (not shown). The tap was fully opened to supply tap water at about 0.5 MPa, and the water discharged from the bubble generating unit 2000 was collected in a bucket. This water was filled into a 75 ml glass bottle, capped, and left indoors. The amount of bubbles was measured after about 12 hours. In the same manner, the results were also measured when the twin bubble generating devices 1500 and 1500 shown in FIG. 12 were used. The results are shown in Table 1. The measurements were performed using a nanoparticle size distribution measuring device (SALD-7500nanao) manufactured by Shimadzu Corporation. The width of the slit 1300 of the bubble generating device 1000 used was 0.4 mm, the diameter of the inner circumferential surface of the main body 1100 was 6 mm, and the length of the main body 1100 was 4 mm. Similarly, the width of the slit 1300 of the air bubble generator 1500 is 0.5 mm, the diameter of the inner circumferential surface of the main body 1100 is 8 mm, and the length of the main body 1100 is 4 mm.

[0031] [Table 1] The results in Table 1 show that a sufficient amount of so-called nanobubbles was generated. The bubble generating unit of the present invention, which generates the above amount of nanobubbles in a single pass of tap water, has a wide range of uses.

[0032] The amount of dissolved oxygen (mg / L) when oxygen is supplied to tap water supplied to the bubble generating unit shown in Figure 4 is as follows. (A) Oxygen supply 0.3L / min: 31.4mg / L (B) Oxygen supply amount 0.5L / min: 33.5mg / L (C) Oxygen supply 1.0L / min: 34.88g / L Oxygen was supplied by bubbling from an oxygen cylinder to the upstream side of the bubble generating unit. The dissolved oxygen content of the tap water itself was 7.6 mg / L (26.5°C). The change in the amount of dissolved oxygen in the water obtained in experiment (C) is shown in FIG. The amount of dissolved oxygen was measured by the polarographic electrode method using a Hanna Instruments Japan HI98193.

[0033] (Embodiment 2) A second embodiment of the present invention will now be described. In the second embodiment of the present invention, the first model of the present invention is defined as follows: (1) A bubble generating device comprising a cylindrical main body and a bubble generating unit disposed within the main body, The bubble generating unit is A base portion having a water flow hole whose diameter decreases along the water flow direction; a plurality of pillars connecting the base portion and an inner circumferential surface of the main body, The column has a recess on the back side in the water flow direction, forming an air bubble generating device. According to the first model air bubble generator thus defined, the water flowing through the main body and passing through the base of the air bubble generator increases in flow velocity at the water flow hole, which narrows in diameter along the water flow direction, and generates a large negative pressure when discharged from the outlet of the water flow hole. In addition, because a recess is formed on the rear side of the pillars, when the water flow that passes between the pillars turns around to the rear side, it is sucked into the recess, increasing its flow velocity and generating a negative pressure there. In this way, a plurality of negative pressure areas are formed immediately downstream of the bubble generating section, and as a result, a sufficient amount of minute bubbles are generated in the negative pressure areas.

[0034] In the above, the through hole of the cylindrical main body is preferably in the shape of an orifice. Both ends of the main body are preferably provided with connection parts for connecting to a pipe or a hose. Such connection parts may be provided with a screw thread. The air bubble generator of this invention takes in the water flow (0.15 MPa to 0.75 MPa) supplied from a water supply pipe directly into the main body, i.e., without accelerating it with any pump, etc., and generates microbubbles in the negative pressure area immediately downstream of the air bubble generator. Therefore, it is preferable that the diameter of the through hole in the main body is 10 to 30 mm, and its outer diameter is also equal to the outer dimensions of the water supply pipe. Of course, this does not in any way exclude the use of a pump or other device to accelerate tap water and introduce it into the bubble generating device of the present invention, but one of the advantages of this invention is that it can generate nano-sized bubbles without the need for a pump, etc. (i.e., simply and inexpensively). This does not exclude the possibility of introducing a water flow in which bubbles have been generated using another air bubble generating device or the air bubble generating device of the present invention into the air bubble generating device of the present invention.

[0035] The second model of the present invention is defined as follows: In the air bubble generating device defined in the first model, the column has a water flow facing surface that faces the water flow and is inclined, the recess is formed in the water flow direction from the back surface of the column, and the wall surface of the recess is parallel to the water flow facing surface. According to the second model bubble generating device defined in this manner, the water flow-facing surface of the pillar is inclined, making it easy to change the flow of the water (increase its speed), and since the wall surface of the recess is parallel to this water flow-facing surface, the depth of the recess formed on the back surface of the pillar (the length in the opposite direction to the water flow) can be maximized. Furthermore, the pillar portion having such a configuration does not have an undercut portion in the direction of the water flow, and therefore has a shape suitable for molding resin.

[0036] The third model of the present invention is defined as follows: In the air bubble generator defined in the second model, the cross-sectional shape of the column along the water flow is a V-shape that expands along the water flow. According to the bubble generating device defined in the third model thus defined, there are multiple V-shaped pillar sections whose diameter expands along the water flow, so that the distance between the inclined surfaces of the opposing pillar sections (which become the water flow acceleration holes (14th model)) is reduced in diameter along the water flow direction, and as a result, the water flow between the pillar sections is accelerated and the cavitation effect is increased. According to the study by the inventors, when tap water is introduced directly from a water supply pipe, in the third model, the number of pillars is preferably 3 to 5, and the included angle of the V is preferably 15 to 35 degrees (fourth model). Here, if the number of pillars is less than 3, the gap between the pillars becomes too wide, and the water flow from the tap cannot be accelerated sufficiently. Also, if the number of pillars exceeds 5, the resistance of the pillars to the water flow from the tap becomes too large, which is not preferable. If the included angle of the V is less than 15 degrees, the pillars become too thin, and the gap between the pillars is not sufficiently narrowed, and the water flow flowing therebetween may not be accelerated sufficiently. Also, if the included angle of the V exceeds 35 degrees, the pillars become too thick, and the resistance to the water flow increases unnecessarily.

[0037] The fifth model of the present invention is defined as follows: In the air bubble generator according to the third or fourth model, the V-shaped tip of the column is located at the upstream end of the base with respect to the water flow, and the V-shaped open end of the column is located at the downstream end of the base. According to the fifth model of the bubble generator thus defined, the base and the columnar part constituting the bubble generating part have the same length in the water flow direction. This makes the structure of the bubble generating part compact, and thus the size can be reduced. In addition, since the downstream end of the base and the downstream end of the columnar part are at the same position in the water flow direction, the negative pressure area formed at the outlet of the base and the negative pressure area formed on the back side of the columnar part are as close as possible. As a result, the cavitation effect is increased. If the negative pressure areas are separated, each negative pressure area is affected by the surroundings and becomes unstable, but if the negative pressure areas are close to each other, they sometimes overlap and expand, which is thought to stabilize the negative pressure area.

[0038] The sixth model of the present invention is specified as follows: That is, in any of the bubble generating devices specified in the first to fifth models, the plurality of pillars are evenly arranged around the base, and the centers of the recesses on the back surface of each of the pillars are positioned on imaginary radial lines extending from the center of the outlet of the water flow hole in the direction perpendicular to the water flow. According to the sixth model of the bubble generator thus defined, the centers of the recesses on the rear surface of the columns are evenly distributed around the water flow hole of the base, so that the negative pressure areas formed on the rear surface of each column are evenly distributed with respect to the negative pressure areas formed downstream of the water flow hole of the base, and therefore each negative pressure area is stable.

[0039] The seventh model of the invention is defined as follows: That is, in any of the air bubble generators defined in the first to sixth models, the center line of the water flow hole of the base coincides with the center line of the cylindrical main body. According to the bubble generator defined in the seventh model, the base is disposed at the center of the main body, so that the water flow speed around the base is constant. This makes the negative pressure area formed on the back side of the column more uniform around the base, and together with the negative pressure area formed downstream of the base, the total negative pressure area formed downstream of the bubble generator is stabilized.

[0040] The eighth model of the invention is specified as follows: In any of the air bubble generating devices specified in the first to seventh models, an air hole is formed that communicates between the outer surface of the cylindrical main body and the recess of the column. According to the eighth model of the bubble generator thus defined, it is possible to forcibly supply gas (oxygen, carbon dioxide, nitrogen, etc.) from the outside through the vent hole, thereby forming minute bubbles of the supplied gas. In this case, it is sufficient to form a vent hole in the recess of one of the columns (ninth model).

[0041] When forming microscopic air bubbles, it is preferable to block the air hole on the outer surface side of the main body. If the diameter of the vent hole blocked on the outer surface is set to 0.5 to 10 mm and an air pocket is formed there, the efficiency of generating microbubbles is improved. This is because the water flow into the recess on the back side of the column interferes with the water flow out of the recess, causing water flow vibration. Here, if the recess is connected to the air pocket, it is thought that the water flow vibration is stabilized and even amplified. Vibration is also thought to be one of the mechanisms that generate air bubbles in water.

[0042] The tenth model of the present invention is specified as follows: That is, in any of the bubble generating devices specified in the first to ninth models, a circumferential convex rib is formed on the inner circumferential surface of the main body between the outlet and the bubble generating part. According to the 10th model bubble generator defined in this manner, the convex ridges on the inner surface of the main body interfere with the negative pressure area formed downstream of the bubble generation section, thereby improving the cavitation effect there. The height, width, number and distance from the bubble generating portion of the ridges can be designed as desired. The ridges may be continuous or discontinuous.

[0043] A screw thread can also be used as the convex ridge (model 11). When a screw thread is provided on the inner peripheral surface of the main body, the bubble generator can be easily connected to another device by inserting a pipe with a threaded tip into the main body and screwing it together. In this case, the generation of fine bubbles can sometimes be controlled by adjusting the distance between the inserted pipe and the bubble generator.

[0044] The invention of the twelfth model of this invention is specified as follows: That is, in any one of the bubble generating devices specified in the first to eleventh models, the main body part comprises an upstream side tubular part having a first through hole and a downstream side tubular part having a second through hole, and a first recess having a larger diameter than the bubble generating part is formed around the first through hole on the downstream facing surface of the upstream side tubular part, A part of the main body is airtightly inserted into the second through hole of the downstream cylindrical portion, and the remaining part of the main body is inserted into the first recess with its tip facing the first through hole. According to the 12th model air bubble generator thus defined, the main body is divided into two parts, and the air bubble generator is inserted between the two parts. Each part of the main body divided into two parts (the upstream cylinder part and the downstream cylinder part) is a cylindrical member, so that it is possible to mold (e.g., by injection) using a resin material. In addition, the air bubble generator, which is made up of a base part and a column part, can also be molded in the same way, so that the entire device can be made of resin, thereby reducing manufacturing costs. Furthermore, in this model, a first recess with a larger diameter than the bubble generating part is formed on the downstream facing surface of the upstream tubular part, making assembly easier. That is, a part of the bubble generating part is liquid-tightly inserted into the second through hole of the downstream tubular part. As a result, the remaining part of the bubble generating part protrudes from the downstream tubular part. In contrast, a first recess with a larger diameter than the bubble generating part is formed on the downstream facing surface of the upstream tubular part, so the remaining part of the protruding bubble generating part can be easily accommodated in the first recess of the upstream tubular part.

[0045] The thirteenth model of the present invention is defined as follows: That is, in the air bubble generating device defined in the twelfth model, a hole is formed in the downstream cylindrical portion, which communicates its outer surface with the second through hole. According to the air bubble generating device defined in the thirteenth model thus defined, the outer surface and the second through hole are connected by a hole, thereby obtaining the air hole defined in the eighth model. From the viewpoint of molding the downstream side tubular portion, it is preferable to form this hole with a core. In that case, it is preferable to make the hole diameter on the outer surface side larger than that on the second through hole side to ensure the releasability of the core.

[0046] The invention of the 14th model of the present invention is defined as follows: That is, a bubble generating device comprising a cylindrical main body and a bubble generating unit disposed in the main body, The bubble generating unit is A cylindrical base portion arranged concentrically with the main body portion, the base portion having an inner circumferential surface that is tapered along the water flow direction; A plurality of water flow acceleration holes are formed on the outer peripheral surface of the base, the diameter of which is reduced along the water flow direction; A partition wall separating the water flow acceleration hole, the partition wall having a recess formed on a back side thereof in the water flow direction; A bubble generating device comprising:

[0047] According to the air bubble generator defined in the 14th model defined in this way, the water flowing through the main body and passing through the base of the air bubble generating part accelerates in the water flow hole whose diameter decreases along the water flow direction, and generates a large negative pressure when discharged from the outlet of the water flow hole. In addition, since a recess is formed on the rear side of the partition wall, when the water flow that has passed through the water flow acceleration hole turns around to the rear side, it is sucked into the recess, further increasing the flow speed and generating negative pressure there. In this way, a negative pressure area is formed immediately downstream of the bubble generating section, and as a result, a sufficient amount of minute bubbles are generated in this negative pressure area. In the above, the peripheral wall of the partition wall that defines the water flow acceleration hole is not limited to the inclined surface defined in the second model, and can also be formed with a curved surface (linear curved surface, multi-dimensional curved surface). The width of the water flow acceleration hole may vary in the radial direction of the main body (direction perpendicular to the water flow).

[0048] In this invention, a base with a water flow hole is placed in the center of the bubble generating unit, and this base is connected to the inner wall of the through hole in the main body with a column. In the bubble generating device introduced as a conventional example, the screws protrude from the inner wall of the through hole, and the tip of each screw is free. In this case, the screws are in a cantilevered state and are mechanically unstable, which raises concerns about durability. In contrast, in this invention, the tip of the column is connected to the base, so the bubble generating unit is mechanically stable and can be given high durability.

[0049] The column used in this invention has a recess on the back side when viewed from the direction of the water flow. When the water flow that has passed the side of the column reaches the back side, it is sucked into the recess and turns around, increasing its speed and creating a high cavitation effect. Cross sections of examples of such pillars are shown in Figures 1 to 3. In the figures, → indicates a water flow. The column 10 shown in FIG. 14(A) has a trapezoidal cross section and a recess 15 on its back surface 14, which corresponds to the base of the trapezoid. That is, the column 10 has a flat top 12, a pair of inclined surfaces 13, 13, and a flat back surface 14. The interval between the inclined surfaces 13, 13 gradually increases in the water flow direction. That is, the inclined surfaces 13, 13 expand in diameter in the water flow direction. The recess 15 draws in the water flow and increases the speed of the water flow downstream of the back surface 14. There is no particular limitation on its shape as long as it has such an effect. In the example of FIG. 14(A), the column 10 has a side wall portion parallel to the inclined surfaces 13, 13 from the back surface 14 to the top, and a semicircular bottom wall portion connecting the side wall portions. The depth of the recess 15 can be designed arbitrarily, but it is preferable that the ratio of the opening to the depth of the recess 15 is 1:0.5 to 3. In this example, the center of the opening of the recess 15 coincides with the center of the back surface 14, but the two may be offset from each other.

[0050] Also, a plurality of recesses 16, 16 may be provided as in the column portion 11 shown in Fig. 14(B). In this example, each recess 16 is similar to the recess 15, but the shape is arbitrary, and each recess may have a different shape. In this example, each recess 16, 16 is evenly distributed on the back surface 14. By varying the volume of the recesses 16, 16 or varying the distance from the slopes 13, 13 to the recesses 16, 16, the water flow speed that wraps around the back surface 14 can be changed, and the cavity effect can be increased by adjusting the degree of the change. The recesses 15, 16 are preferably continuous in the axial direction (vertical direction) of the column 10, but may be discontinuous (the same applies to the other columns described below). If they are discontinuous, they can be formed in a part of the back surface of the column, preferably on the base side. Another example of the pillar portion 18 is shown in Fig. 14(C). The same elements as those in Fig. 14(A) are given the same reference numerals and their explanations are omitted. In this example, one of the inclined surfaces 13' is parallel to the water flow. The recess 17 has side walls parallel to the inclined surfaces 13 and 13' and a semicircular bottom wall connecting the side walls.

[0051] Figure 15(A) shows another example of a column section 20. The same elements as those in Figure 14 are given the same reference numerals, and their explanation will be partially omitted. The cross-sectional outline of this column section 20 is triangular (isosceles triangle), with the apex facing the water flow direction. A recess 25 is provided on the back surface 14, which corresponds to the base of the triangle. Multiple recesses can be formed as in Figure 14(B). The included angle α of the inclined surfaces 23, 23 is preferably 10 to 35 degrees. More preferably, it is 20 to 35 degrees, and even more preferably, it is 25 degrees. The inclined surfaces 23, 23 open evenly in the water flow direction. In other words, the bisector of the apex coincides with the water flow direction. 15(B) has a V-shaped cross section. That is, the side walls of the recess 25 are parallel to the inclined surfaces 23, 23. 15(C), the lengths of the slopes 23, 23' are different. This causes a change in the water flow rate from the slopes 23, 23' into the recess 25', which may increase the cavitation effect in the downstream area of ​​the recess 25.

[0052] Figure 16(A) shows another column 30. In Figure 16(A), the same elements as those in Figure 14(A) are given the same reference numerals and their explanations are omitted. In this column 30, the outer contour of the top 32 is made into an arc shape. This reduces the resistance of the column to the water flow and increases the cavitation effect. From the standpoint of further reducing the resistance of the pillars to the water flow, the outer peripheral wall 33 of the pillars 31 can be made generally streamlined, as shown in FIG. 16(B). 16(C) is formed in an arc shape. That is, the outer peripheral wall 34 is semicircular, and the peripheral wall of the recess 35 is also semicircular and concentric with the outer peripheral wall 34. In the example of Fig. 16(D), the pillars 38 are rotated in the circumferential direction. This causes the speed of the water flowing into the recess 35 to differ in the up-down direction in Fig. 16(D), which may increase the cavitation effect in the downstream area of ​​the recess 35.

[0053] The effect of tilting the pillars with respect to the water flow as shown in FIG. 16(D) will be explained below. Figure 17(A) shows the pressure distribution downstream of a cylinder with a hemispherical cross section when the cylinder is placed directly facing the water flow. Similarly, Figure 17(B) shows the pressure distribution when the cylinder is tilted. As is clear from Figure 17(B), the negative pressure area expands when the cylinder is tilted. It is believed that the same effect can be achieved with the pillar portion 38 shown in FIG. 16(D) and the pillar portion 28 shown in FIG. 14(C).

[0054] An example of an air bubble generating device 100 employing the column portion 21 of Fig. 15(B) is shown in Fig. 18. This air bubble generating device 100 comprises a main body portion 110 and an air bubble generating portion 130. The main body 110 is cylindrical and includes an upstream cylindrical portion 111 and a downstream cylindrical portion 121. A through hole (first through hole) 113 of the upstream cylindrical portion 111 gradually decreases in diameter from the open end toward the center, and the diameter of the decreased diameter portion is the same as that of a through hole (second through hole) 123 of the downstream cylindrical portion 121. The bubble generating part 130 comprises a base 131 and a column part 21. The base 131 is a cylindrical member whose inner diameter decreases along the water flow direction to form a water flow hole 133. The center line of the base 131 coincides with the center line of the main body part 110. In this example, there is one water flow hole 133, but multiple water flow holes 133 can also be provided. 15(B) are arranged on the outer circumferential surface of base 131 in the vertical and horizontal directions (i.e., at equal intervals), and their tip portions are embedded in upstream cylindrical portion 111. As a result of recess 25 of pillar 21 being embedded in upstream cylindrical portion 111, a gap (air pocket) 125 is formed in upstream cylindrical portion 111. The hole (water flow acceleration hole 135) formed by adjacent column sections 21, 21, the outer surfaces of the bubble generating section 131 and the inner surface of the main body section 121 has a cross-sectional area that gradually decreases from the upstream side to the downstream side along the side of the column section 21, accelerating the water flow. In the air bubble generation device 100 configured in this manner, negative pressure areas are formed downstream of the water flow holes 133 in the base 130 and downstream of the recesses 25 in the column 21, where fine air bubbles are generated.

[0055] Figure 19 shows another example of an air bubble generating device 200. In Figure 19, elements having the same configuration as those in Figure 18 are given the same reference numerals and their description will be omitted. The air bubble generating device 200 comprises a cylindrical main body 110 and an air bubble generating part 220 , and the air bubble generating part 220 has a structure in which a column part 21 is suspended within a through hole of the main body 110 . In the air bubble generator 200 thus constructed, the recesses 25 are formed on the rear surface of the pillars 21, so that when the water flow passing between the pillars 21 flows around to the rear surface of the pillars 21, it is sucked into the recesses 25 and its flow speed increases, resulting in the generation of a large negative pressure. This creates a negative pressure area downstream of the pillars 21, where microbubbles are generated.

[0056] Fig. 20 shows another example of an air bubble generating device 300. In Fig. 20, elements having the same configuration as those in Fig. 19 are given the same reference numerals and their description will be omitted. This air bubble generating device 300 includes a cylindrical main body 110 and an air bubble generating section 320. The air bubble generating section 320 is configured by arranging the pillars 21 in a lattice pattern. In this air bubble generator 300, a negative pressure area is formed downstream of the pillar portion 21, as in the example of FIG. 19, and micro-air bubbles are generated there. In the example of Figures 19 and 20, the column portion 21 having the V-shaped cross section shown in Figure 15(B) is used, but it is also possible to use column portions of other structures shown in Figures 14 to 17. The posts may also be supported by conventional cantilevers with their free ends facing each other.

[0057] Next, an embodiment of the present invention will be described. FIG. 21 shows the structure of the air bubble generating device 400 of this embodiment. The air bubble generating device 400 of the embodiment comprises a main body 410 and an air bubble generating unit 430 . The main body 400 is divided into an upstream cylindrical portion 411 and a downstream cylindrical portion 421, which are bonded together at their abutting surfaces. The upstream cylindrical portion 411 comprises a base portion 415 and a connecting portion 416, and a downstream facing surface 418 of the base portion 415 is bonded to an upstream facing surface 428 of the downstream cylindrical portion 421. A first recess 414 is formed on the downstream facing surface 418 around the first through hole 413. A screw thread is provided on the outer periphery of the connecting portion 416 so that it can be connected exclusively to a water supply pipe.

[0058] Downstream-side tubular portion 421 includes a base portion 425 and a coupling portion 426. The diameter of base portion 425 is the same as that of base portion 415 of upstream-side tubular portion 411. A screw thread is provided on the outer periphery of coupling portion 426 to facilitate coupling to a water pipe or the like. The second through hole 423 of the downstream side tube part 421 includes, from the upstream side, a bubble generating part receiving part 4231, a bubble generating part regulating part 4232, and a discharge part 4233. The inner diameter dimension of the bubble generating part receiving part 4231 is the same as the outer diameter dimension of the bubble generating part 430, so that the bubble generating part 430 is inserted into the receiving part 4231 in a liquid-tight manner by a tight fit. The inner diameter dimension of the bubble generating part regulating part 4232 is slightly smaller than the outer diameter dimension of the bubble generating part 430, so that it serves as a stopper for the bubble generating part 430. The inner diameter of the discharge part 4233 is larger than the inner diameter of the bubble generating part receiving part 4231, and a screw thread 427 is screwed on its inner circumference. A pipe having a screw thread at its tip can be inserted into the discharge part 4233 and screwed into the screw thread 427. In this case, by adjusting the position of the tip of the pipe, the volume and shape downstream of the bubble generating part 430 can be adjusted. By adjusting such volume and shape, the cavitation effect may be increased. Even if a pipe is not inserted, the thread 427 may interfere with the water flow downstream of the bubble generating part 430, affecting and increasing the cavitation effect. An air vent 422 is formed between the outer circumferential surface of the base portion 425 of the downstream side tubular portion 421 and the bubble generating portion receiving portion 4231 of the second through hole 423. The diameter of this air vent 422 gradually increases from the second through hole 423 side toward the outer circumferential surface side. In this example, the air vent 422 is closed by a lid 429 on the outer circumferential surface.

[0059] The configuration of the bubble generating section 430 is shown in FIGS. This bubble generating part 430 comprises a cylindrical base part 431 and pillar parts 521 evenly arranged on the outer periphery of the base part 431 . The base portion 431 is formed with a water flow hole 433 that tapers in diameter. 23, the pillar portion 521 is V-shaped in plan view. The included angle α1 of the slope of the pillar portion 521 is about 25 degrees, and the included angle α2 of the peripheral wall of the recessed portion 525 is about 20 degrees. These included angles can be made the same. The top of the pillar portion 521 coincides with the upstream end of the base portion 431, and the bottom surface 524 of the pillar portion 521 coincides with the downstream end of the base portion 431. The four pillars 521 have the same dimensions and are evenly distributed around the base 431. This ensures that the centers of the recesses 525 on the back surface of the pillars 521 are at the same position (in the water flow direction) as the outlets of the water flow holes 433 of the base 431 and are evenly distributed around it. The vent hole 422 communicates with the recess 525 of one of the pillars 521 .

[0060] The simulation results of the pressure in each of the parts A to I of the air bubble generating device 400 configured in this manner were as follows. A: 0.486MPa B: 0.408MPa C: 0.004MPa D: 0.032MPa E: 0.051MPa F: 0.006MPa G: 0.008MPa H: 0.004MPa I: 0.004MPa From the above, it is understood that a negative pressure region is formed over a wide range downstream of the bubble generating section 430. In this negative pressure region, the pressure of the supplied tap water is reduced to about 1 / 1000, thereby exerting a strong cavitation effect.

[0061] The present invention is not limited to the above-mentioned embodiment and examples. Various modifications within the scope of the claims and within the scope that can be easily conceived by a person skilled in the art are also included in the present invention.

[0062] Disclose the following: (A) A bubble generating device including a bubble generating unit that generates minute bubbles in a water flow passing through a tubular main body by protruding a column into the main body, The column portion has a water flow facing surface facing the water flow and a negative pressure generating surface on the back side of the water flow facing surface, and the negative pressure generating surface has a recess. Bubble generator. (B) A bubble generating device including a bubble generating unit that generates minute bubbles in a water flow passing through a tubular main body by protruding a column into the main body, In a cross section perpendicular to the axis of the column, The water flow facing surface forms an arc, A chord connecting both ends of the arc serves as the negative pressure generating surface, and the arc is inclined relative to the flow of the water current. (C) A bubble generating device having a bubble generating unit that generates minute bubbles in a water flow passing through a tubular main body by projecting a column portion into the main body, The column portion has a water flow opposing surface directly facing the water flow and a negative pressure generating surface on the back side of the water flow opposing surface, one edge of the negative pressure generating surface being located upstream of the other edge, in the bubble generating device. (1) A bubble generating device comprising a cylindrical main body and a bubble generating unit disposed within the main body, A base portion having a water flow hole whose diameter decreases along the water flow direction; a plurality of pillars connecting the base portion and an inner circumferential surface of the main body, The column has a recess on the back side in the water flow direction, forming an air bubble generating device. (2) The bubble generating device described in (1), wherein the column has a water flow facing surface that faces the water flow and is inclined, the recess is formed in the water flow direction from the back surface of the column, and the wall surface of the recess is parallel to the water flow facing surface. (3) The bubble generation device described in (2), wherein the cross-sectional shape of the column portion along the water flow is a V-shape that expands in diameter along the water flow. (4) The bubble generation device according to (3), wherein three to five of the pillars are formed around the periphery of the base, and the included angle of the V shape is 15 to 35 degrees. (5) A bubble generating device as described in (3) or (4), wherein the V-shaped tip of the column is located at the upstream end of the base with respect to the water flow, and the V-shaped opening end of the column is located at the downstream end of the base. (6) A bubble generating device as described in any one of claims (1) to (5), wherein the multiple pillars are evenly arranged around the base, and the centers of the recesses on the back surfaces of the pillars are located on imaginary radial lines extending from the center of the outlet of the water flow hole in a direction perpendicular to the water flow. (7) The air bubble generation device according to any one of (1) to (6), wherein a center line of the water flow hole of the base coincides with a center line of the cylindrical main body. (8) The air bubble generation device according to any one of (1) to (7), wherein an air hole is formed so that the outer surface of the cylindrical main body communicates with the recess of the column. (9) The bubble generating device according to any one of (8), wherein an air hole is formed between a recess of one of the plurality of column portions and an outer surface of the main body portion. (10) A bubble generating device described in any one of (1) to (9), wherein a circumferential convex rib is formed on the inner surface of the main body between the outlet of the main body and the bubble generating section. (11) The bubble generating device according to claim 10, wherein a screw thread is formed on the inner circumferential surface of the main body between the outlet of the main body and the bubble generating section. (12) the main body portion includes an upstream cylindrical portion having a first through hole and a downstream cylindrical portion having a second through hole, and a first recess having a larger diameter than the bubble generating portion is formed around the first through hole on the downstream opposing surface of the upstream cylindrical portion, A bubble generation measure described in any of (1) to (11), wherein a portion of the main body is airtightly inserted into the second through hole of the downstream cylindrical portion, and the remaining portion of the main body is inserted into the first recess with its tip facing the first through hole. (13) The bubble generation device described in (12), wherein the downstream side cylindrical portion has a hole that communicates with its outer surface and the second through hole. (14) A bubble generating device comprising a cylindrical main body and a bubble generating unit disposed within the main body, The bubble generating unit is A cylindrical base portion arranged concentrically with the main body portion, the base portion having an inner circumferential surface that is tapered along the water flow direction; A plurality of water flow acceleration holes are formed on the outer peripheral surface of the base, the diameter of which is reduced along the water flow direction; A partition wall separating the water flow acceleration hole, the partition wall having a recess formed on a back side thereof in the water flow direction; A bubble generating device comprising: (twenty one) A bubble generating device comprising a cylindrical main body and a bubble generating unit disposed within the main body, The bubble generating section has slits extending radially from a center point in the main body section in a cross section of the main body section, a pillar portion that bulges out from an inner peripheral surface of the main body portion and forms a periphery of the slit, The amount of bulging of the pillar portion gradually decreases from the periphery of the slit toward the upstream side, and a recess is formed on the downstream side surface of the pillar portion. Bubble generator. (twenty two) The bubble generating device according to (21), wherein the center is located on the central axis of the main body portion. (twenty three) A bubble generating device as described in (21) or (22), in which the cross-sectional area of ​​the column portion gradually decreases toward the upstream side, with the surface defined by each edge of adjacent slits as the downstream side, and the cross-sectional area of ​​the column portion becomes essentially zero at the upstream end of the main body portion. (twenty four) The bubble generating device described in (21) or (22), wherein the column portion is cone-shaped with the surface defined by the edges of the adjacent slits as its base, and the ridge line of the column portion connects the intersection of the edges of the adjacent slits and a point on the inner surface of the main body portion where the imaginary bisectors of the edges intersect. (twenty five) The bubble generation device described in (21) above, wherein the recesses formed on the downstream side surface of the column portion are arranged radially from the center. (26) The air bubble generation device according to any one of (21) to (25), wherein the recess passes through an inner circumferential surface of the main body to form a gap in the circumferential wall of the main body. (27) A bubble generating unit comprising at least one bubble generating device according to any one of (21) to (26) and a housing having an orifice and housing the bubble generating device in a small diameter portion thereof, A bubble generating unit, wherein a main body of the bubble generating device is embedded in the housing, and the column portion is exposed to the small diameter portion of the orifice. (28) The bubble generating device according to (27), wherein the housing portion is divided in the radial direction at the small diameter portion, and the main body portion of the bubble generating device is sandwiched between the divided pieces. (29) The bubble generating device described in (27), wherein the housing portion is divided in the radial direction at the small diameter portion, and one of the divided pieces is integrally molded with the bubble generating device. (a) A bubble generating device comprising a cylindrical main body and a bubble generating unit disposed within the main body, The bubble generating section has a slit extending radially from a center point in the main body section to an inner circumference of the main body section in a cross section of the main body section, a pillar portion that bulges out from an inner peripheral surface of the main body portion and forms a periphery of the slit, The pillar portion has a portion whose bulge gradually decreases toward the upstream side, the slit communicates from the upstream side to the downstream side in the bubble generating section, and becomes wider toward the upstream side in a portion where the expansion amount of the columnar section decreases; Bubble generator. (b) The bubble generating device described in (a), wherein the slit is narrowest on the downstream side of the column portion and has the same width in a direction perpendicular to the axis of the main body portion. (c) A bubble generating device as described in (a) or (b), wherein the center is located on the central axis of the main body portion. (d) A bubble generating unit comprising at least one of the bubble generating devices according to any one of (a) to (c) and a housing having an orifice and housing the bubble generating device in a small diameter portion thereof, A bubble generating unit, wherein a main body of the bubble generating device is embedded in the housing, and the column portion is exposed to the small diameter portion of the orifice. (e) The bubble generating unit of (d), wherein the housing portion is divided radially at the small diameter portion, and the main body portion of the bubble generating device is sandwiched between the divided pieces. (f) A bubble generating unit as described in (d), wherein the housing portion is divided radially at the small diameter portion, and one of the divided pieces is integrally molded with the bubble generating device. (30) [Explanation of symbols]

[0063] 1000,1500 Bubble Generator 1100 Main unit 1200 Bubble generating section 1210,1710 Column part 1215,1715 Ridgeline 1220 Recess 1300 Slit 1310 Edge of slit 2000,3000 Bubble generating unit 2100, 3100 housing 2110,3100 Orifice 10,11,18,20,21,28,30,31,38,521 Column part 15,16,17,25,25',35,525 recess 100,200,300,400 Bubble Generator 110,410 Main body 130, 220, 320, 430 Bubble generating section 133,433 Water hole 111,411 Upstream cylinder part 121,421 Downstream tube section 422 Vent

Claims

1. At least one air bubble generating device comprising a cylindrical main body and an air bubble generating unit disposed within the main body, The bubble generating section has slits extending radially from a center point in the main body section in a cross section of the main body section, a pillar portion that bulges out from an inner peripheral surface of the main body portion and forms a periphery of the slit, the at least one bubble generating device, the pillar portion having a gradually decreasing bulge amount from the periphery of the slit toward the upstream side; A bubble generating unit comprising a housing having an orifice and housing the at least one bubble generating device in a small diameter portion thereof, A bubble generating unit, wherein a main body portion of the at least one bubble generating device is embedded in the housing portion, and the column portion is exposed to the small diameter portion of the orifice.

2. The bubble generating unit according to claim 1 , wherein a recess is formed on a downstream side surface of the column.

3. A bubble generating unit as described in claim 1 or 2, wherein the cross-sectional area of ​​the column portion gradually decreases toward the upstream side, with the surface defined by each edge of adjacent slits as the downstream side, and the cross-sectional area of ​​the column portion becomes essentially zero at the upstream end of the main body portion.

4. A bubble generating unit as described in claim 1 or 2, wherein the column portion has a cone shape with a base defined by the edges of adjacent slits, and the ridge line of the column portion connects the intersection of the edges of adjacent slits and a point on the inner surface of the main body portion where the imaginary bisectors of the edges intersect.

5. The bubble generating unit according to claim 1 , wherein the recesses formed on the downstream side of the column are arranged radially from the center.

Images