Bubble generating device and bubble generating system

Abstract

The present invention relates to a bubble generating device and a bubble generating system. The present invention provides a bubble generating device (1) which is installed in a liquid tank (10) and generates fine bubbles in a liquid in the liquid tank (10). The bubble generating device (1) is provided with a vibrating plate (2), a first cylindrical body (31), a spring portion (32), a second cylindrical body (33), a flange portion (34), a third cylindrical body (35), a counterweight portion (36), and a piezoelectric element (4). The third cylindrical body (35) and the counterweight portion (36) are disposed at positions where, in a case where the spring portion (32) is vibrated by the piezoelectric element (4), a displacement amount of a side surface of the second cylindrical body (33) is within a prescribed range.

Description

Technical Field

[0001] This disclosure relates to bubble generating apparatus and bubble generating system. Background Technology

[0002] In recent years, microbubbles have been used in various fields such as water purification, wastewater treatment, and fish farming. Therefore, a bubble generating device for producing microbubbles has been developed (Japanese Patent No. 6108526: Patent Document 1).

[0003] In the bubble generating apparatus described in Patent Document 1, a piezoelectric element is used to generate fine bubbles. In this bubble generating apparatus, the up-and-down vibration of the central part of a bending vibrating plate is used to tear the bubbles generated at the fine holes formed by the vibration, thereby miniaturizing them.

[0004] Patent Document 1: Japanese Patent No. 6108526

[0005] For applications of bubble generating devices, such as automotive applications where light oil is bubbled to improve combustion in diesel engines, high reliability is required. Therefore, the bubble generating device needs to incorporate measures to prevent leakage of the liquid (light oil) from the liquid tank at the connection point between the liquid tank and the bubble generating device. Summary of the Invention

[0006] Therefore, the purpose of this disclosure is to provide a bubble generating device and a bubble generating system in which the liquid in the liquid tank does not easily leak from the joint between the liquid tank and the bubble generating device.

[0007] One aspect of this disclosure relates to a bubble generating device that is installed in a liquid tank to generate fine bubbles in the liquid. The device comprises: a vibrating plate having multiple openings and positioned such that one side contacts the liquid in the liquid tank and the other side contacts the gas; a first cylindrical body supporting one end of the vibrating plate; a plate-shaped spring supporting the other end of the first cylindrical body; a second cylindrical body supporting the spring at an end located further outward than the position supporting the first cylindrical body; a plate-shaped flange supporting the other end of the second cylindrical body and extending outward from the position supporting the second cylindrical body; a third cylindrical body supporting the flange at an end located further outward than the position supporting the second cylindrical body; a counterweight at the other end of the third cylindrical body; and a piezoelectric element disposed on the surface of the spring supported by the second cylindrical body, causing the spring to vibrate. The third cylindrical body and the counterweight are positioned such that the displacement of the side surface of the second cylindrical body is within a predetermined range when the spring is vibrated by the piezoelectric element.

[0008] Another aspect of this disclosure relates to a bubble generating system comprising the aforementioned bubble generating device and liquid tank.

[0009] According to this disclosure, in the bubble generating device, since a third cylindrical body and a counterweight are provided, the displacement of the joint with the liquid tank can be adjusted to be within a specified range, thereby making it less likely for the liquid in the liquid tank to leak from the joint between the liquid tank and the bubble generating device. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of a bubble generating system using the bubble generating apparatus according to this embodiment.

[0011] Figure 2 This is a perspective view of the bubble generating apparatus according to this embodiment.

[0012] Figure 3 This is a cross-sectional view of the bubble generating apparatus according to this embodiment.

[0013] Figure 4 This is a half-sectional view of the bubble generating apparatus according to this embodiment.

[0014] Figure 5 This is a half-sectional view of a bubble generating device of a different type, with the counterweight located at the other end of the third cylindrical body.

[0015] Figure 6 This is a graph showing the displacement in the Z direction of the side of an object of type A in the bubble generating apparatus according to this embodiment.

[0016] Figure 7 This is a graph showing the displacement in the X direction of the side of an object of type A in the bubble generating apparatus according to this embodiment.

[0017] Figure 8 It is a graph showing the change in average displacement relative to the length at position D.

[0018] Figure 9 It is a graph showing the change in the average displacement in the Z direction for each type relative to the length of position D.

[0019] Figure 10 It is a graph showing the change of the inertial torque relative to the length of position D.

[0020] Figure 11 It is a graph representing the displacement in the Z direction relative to the density of the counterweight.

[0021] Figure 12 This diagram shows an example of machining the end of the spring into a tapered shape. Detailed Implementation

[0022] (Implementation Method)

[0023] Hereinafter, the bubble generating apparatus and bubble generating system according to this embodiment will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0024] first, Figure 1 This is a schematic diagram of a bubble generating system 100 using the bubble generating apparatus 1 according to this embodiment. Figure 1 The bubble generating device 1 shown is installed at the bottom of a liquid tank 10 containing liquids such as water, gasoline, or light oil, and is used to generate fine bubbles 200 in the liquid in the liquid tank 10. Furthermore, the bubble generating system 100 can be applied to various systems such as water purification devices, drainage treatment devices, fish farming tanks, and fuel injection devices.

[0025] Furthermore, the liquid introduced into the liquid tank 10 varies depending on the system being applied; for example, it is water in a water purification device, but liquid fuel in a fuel injection device. Additionally, the liquid tank 10 only needs to be able to temporarily store liquid, and also includes a tank in which the liquid continuously flows within the pipe through which it is introduced.

[0026] The bubble generating device 1 includes a vibrating plate 2, a cylindrical body 3, and a piezoelectric element 4. The bubble generating device 1 causes the vibrating plate 2, which has a hole provided in a part of the bottom of the liquid tank 10 and protrudes from the hole to the liquid side, to vibrate by means of the piezoelectric element 4, thereby generating fine bubbles 200 from a plurality of fine holes (openings) formed in the vibrating plate 2.

[0027] The vibrating plate 2 can be formed from materials such as resin plates, metal plates, Si or SOI (Silicon on Insulator) substrates, porous ceramic plates, or glass plates. When the vibrating plate 2 is formed from a glass plate, it can be, for example, a glass plate that allows transmission of ultraviolet and deep ultraviolet light with wavelengths from 200 nm to 380 nm. By forming it from a glass plate that allows transmission of both ultraviolet and deep ultraviolet light, a light source that emits ultraviolet light from the other side of the vibrating plate 2 relative to the liquid in the liquid tank 10 can be provided, enabling both ozone-based sterilization and ultraviolet light-based sterilization.

[0028] The vibrating plate 2 has multiple fine holes, with one side in contact with the liquid (e.g., water) in the liquid tank 10 and the other side in contact with the gas (e.g., air). That is, in the bubble generating device 1, the vibrating plate 2 separates the liquid from the air, applying back pressure to the other side. Figure 1(As indicated by the arrow), the gas is thus fed into the liquid in the liquid tank 10 through multiple fine holes. The bubble generating device 1 generates microbubbles 200 by using the vibration of the vibrating plate 2 to tear the gas fed into the liquid through the multiple fine holes.

[0029] To explain in more detail, when gas attempts to escape from multiple pores, the surface tension of the liquid hinders its intrusion into the liquid side. On the other hand, the buoyancy of the gas breaks this surface tension. The diameter of the bubble 200 is determined by this balance, but the vibration of the vibrating plate 2 creates an effect of the pores peeling off from the wall, resulting in a state similar to reduced surface tension. As a result, in the initial stage when gas attempts to escape from multiple pores, the vibration of the vibrating plate 2 tears the gas apart, enabling the generation of micro-bubbles 200 with a diameter of approximately 1 / 10 compared to the case where the vibration of the vibrating plate 2 is not applied.

[0030] Although not shown in the figure, for example, multiple micropores are formed in a 5mm × 5mm area at the center of the vibrating plate 2 with a diameter of 14mm. When the diameter of the micropores is set to 1μm and the spacing between the micropores is set to 0.25mm, 441 micropores can be formed in the 5mm × 5mm area.

[0031] In the bubble generating device 1, the vibrating plate 2 is vibrated via the piezoelectric element 4 through the cylindrical body 3. Figure 2 This is a perspective view of the bubble generating device 1 according to this embodiment. Figure 3 This is a cross-sectional view of the bubble generating apparatus according to this embodiment. Figure 3 As shown, Figure 1 The shown cylindrical body 3 includes a first cylindrical body 31, a spring portion 32, a second cylindrical body 33, a flange portion 34, a third cylindrical body 35, and a counterweight portion 36. Furthermore, Figure 3 The bubble generating device 1 is a cross-sectional view cut off at the center along the through direction of the second cylindrical body 33 (vertical direction in the figure).

[0032] The end of the vibrating plate 2 is held by the end of a cylindrical first cylindrical body 31. The vibrating plate 2 is supported by the first cylindrical body 31 at a position where the direction of the plurality of fine holes formed in the vibrating plate 2 is parallel to the vibration direction of the first cylindrical body 31. The end of the first cylindrical body 31 opposite to the vibrating plate 2 is supported by a spring portion 32. The spring portion 32 is a plate-shaped component capable of elastic deformation, supporting the bottom surface of the cylindrical first cylindrical body 31 and extending outwards from the first cylindrical body 31. The spring portion 32 does not have holes penetrating the first cylindrical body 31 and the second cylindrical body 33, but has at least one connecting portion 320 for gas to flow into the first cylindrical body 31 from the side. By not providing holes penetrating the first cylindrical body 31 and the second cylindrical body 33 in the spring portion 32, liquid leaking from the plurality of fine holes formed in the vibrating plate 2 will not leak to a lower level than the second cylindrical body 33, thus protecting the piezoelectric element 4 from the influence of the liquid. Of course, the spring portion 32 can also be hollow and circular, with a hole passing through the first cylindrical body 31 and the second cylindrical body 33. Alternatively, the connecting portion 320 may not be provided in the spring portion 32.

[0033] The spring portion 32 is supported by the second cylindrical body 33 at a position outside the support of the first cylindrical body 31. The second cylindrical body 33 is cylindrical in shape. The second cylindrical body 33 supports the spring portion 32 at one end. The end of the second cylindrical body 33 opposite to the spring portion 32 is supported by a flange portion 34. The flange portion 34 is a plate-shaped component that supports the bottom surface of the cylindrical second cylindrical body 33 and extends outward from the position supporting the second cylindrical body 33.

[0034] The flange 34 is supported by the third cylindrical body 35 at a position outside the support of the second cylindrical body 33. The third cylindrical body 35 is cylindrical in shape. The third cylindrical body 35 supports the flange 34 at one end. At the other end of the third cylindrical body 35, a cylindrical counterweight 36 is provided on the outer side. Furthermore, the third cylindrical body 35 and the counterweight 36 are positioned such that the displacement of the side of the second cylindrical body 33 is within a predetermined range when the spring part 32 is vibrated by the piezoelectric element 4.

[0035] A circular piezoelectric element 4 is provided on the lower surface of the spring portion 32, matching the shape of the spring portion 32. The piezoelectric element 4 vibrates in the penetrating direction (vertical direction in the figure) of the first cylindrical body 31. The vibration of the piezoelectric element 4 in the penetrating direction of the first cylindrical body 31 causes the spring portion 32 to vibrate in the penetrating direction of the first cylindrical body 31, causing the first cylindrical body 31 to be displaced approximately uniformly in the vertical direction. Furthermore, the piezoelectric element 4 may not be a circle covering the entire inner diameter of the second cylindrical body 33, but rather a hollow circle with a hole in the center.

[0036] The first cylindrical body 31, spring portion 32, second cylindrical body 33, flange portion 34, third cylindrical body 35, and counterweight portion 36 are integrally formed. The first cylindrical body 31, spring portion 32, second cylindrical body 33, flange portion 34, third cylindrical body 35, and counterweight portion 36 are made of, for example, a metal such as stainless steel or a synthetic resin. Preferably, a metal with high rigidity such as stainless steel is preferred. Alternatively, the first cylindrical body 31, spring portion 32, second cylindrical body 33, flange portion 34, third cylindrical body 35, and counterweight portion 36 can be formed as separate parts, forming separate components. The method of joining the vibrating plate 2 to the first cylindrical body 31 is not particularly limited. The vibrating plate 2 and the first cylindrical body 31 can be joined by adhesives, welding, fitting, pressing, etc.

[0037] like Figure 1 As shown, the bubble generating device 1 is connected to a hole in a portion of the bottom of the liquid tank 10 at the outer end of the spring portion 32 or the outer side of the second cylindrical body 33. As will be described later, by providing the third cylindrical body 35 and the counterweight 36, even when the vibrating plate 2 is vibrated using the piezoelectric element 4, the outer end of the spring portion 32 or the outer side of the second cylindrical body 33 hardly vibrates. Therefore, the vibration of the piezoelectric element 4 is not transmitted to the liquid tank 10, and essentially only the vibrating plate 2 vibrates. Furthermore, it is possible to prevent leakage of liquid from the connection between the bubble generating device 1 and the liquid tank 10.

[0038] The piezoelectric element 4 vibrates, for example, by polarization in the thickness direction. The piezoelectric element 4 is made of lead zirconate titanate-based piezoelectric ceramic. However, other piezoelectric ceramics such as (K,Na)NbO3 can also be used. Additionally, piezoelectric single crystals such as LiTaO3 can also be used. The piezoelectric element 4 is based on data from the controller 20 (see reference). Figure 1 The driving signal of the first cylindrical body 31 vibrates in the through direction.

[0039] In the bubble generating apparatus 1, a structure is adopted in which the vibrating plate 2 in contact with the liquid is, for example, a glass plate, and the vibrating plate 2 is vibrated by a piezoelectric element 4 via a cylindrical body 3. This allows the space for introducing gas to be completely separated from the liquid. By completely separating the space for introducing gas from the liquid, it is possible to prevent the electrical wiring of the piezoelectric element 4 from being immersed in the liquid. In addition, in the bubble generating apparatus 1, even if a light source emitting ultraviolet light relative to the liquid in the liquid tank 10 is provided, the light source can be placed in the space for introducing gas, thus preventing the electrical wiring of the light source from being immersed in the liquid.

[0040] Next, the displacement of the outer side surface (the part connected to the liquid tank 10) of the second cylindrical body 33 will be explained in detail by setting a third cylindrical body 35 and a counterweight 36 in the bubble generating device 1. Figure 4This is a half-sectional view of the bubble generating apparatus according to this embodiment. Figure 4 The dotted line shown represents the portion passing through the central axis of the first cylindrical body 31. Furthermore, position A is designated as the inner side of the first cylindrical body 31, position B as the inner side of the second cylindrical body 33, position C as the outer side of the second cylindrical body 33, and position D as the outer side of the third cylindrical body 35. Additionally, the outer end of the spring portion 32 or the outer surface of the second cylindrical body 33 is the side that engages with the liquid tank 10, and is the side that aims to suppress the displacement within a specified range. The penetrating direction of the second cylindrical body 33 (vertical direction in the figure) is designated as the Z direction, and the horizontal direction in the figure is designated as the X direction.

[0041] Figure 5 This is a half-sectional view of a bubble generating device 1 of a different type, which is located at the position of the counterweight 36 at the other end of the third cylindrical body 35. Figure 5 Figure (a) shows a bubble generating device 1 of type A with a length of 7.0 mm from the central axis to the outer side of the counterweight 36. Figure 5 Figure (b) illustrates a type B bubble generating device 1 with a length of 7.5 mm from the central axis to the outer side of the counterweight 36. Figure 5 (a) and Figure 5 In (b), the length from the central axis to the inside of the counterweight 36 varies with the length from the central axis to the inside of the third cylindrical body 35. Figure 5 (c) illustrates a bubble generating device 1 of type C with a length of 7.0 mm from the central axis to the outer side of the counterweight 36 and the inner side of the counterweight 36 fixed at position B.

[0042] for Figure 5 (a)~ Figure 5 For each of the bubble generating devices 1 of type A to type C shown in (c), a simulation is performed to vibrate the vibrating plate 2 using the piezoelectric element 4, and the change in displacement of the object's side is determined. Figure 6 This is a graph representing the displacement in the Z direction of the side of an object of type A, bubble generating device 1. Figure 7 This is a graph representing the displacement in the X direction of the side of an object in type A of the bubble generating device 1. Figure 6 and Figure 7 In this context, the vertical axis is set as the displacement (unit: μm), and the horizontal axis is set as the position on the side of the object (the position on the side of the second cylindrical body 33 from the spring portion 32 to the flange portion 34) (unit: mm). Additionally, in... Figure 6 and Figure 7The figure shows the displacement of the side of the object when the length from the central axis to position D (hereinafter referred to as the length of position D) is varied to 4.5mm (D1), 5.25mm (D2), 5.75mm (D3), 6.0mm (D4), 6.25mm (D5), 6.5mm (D6), 6.75mm (D7), and 7.0mm (D8).

[0043] Figure 8 This is a graph showing the change in average displacement relative to the length at position D. Figure 8 In this diagram, the vertical axis is set to the average displacement (in μm), and the horizontal axis is set to the length of position D (in mm). Figure 8 It is Figure 6 and Figure 7 The graph shown is a plot of displacements averaged for each length from the central axis to position D. Figure 8 It can be seen that in type A of bubble generating device 1, when the length of position D is 6.5 mm, the displacement in the X and Z directions is almost 0 (zero).

[0044] The same simulation was performed on bubble generating devices 1 of types B and C, by conducting... Figures 6-8 The processing shown is similar to type A, with the displacement in the X direction being smaller than that in the Z direction. Furthermore, the longer the length of position D, the smaller the displacement in the X direction. In type B of the bubble generating device 1, when the length of position D is 6.3 mm, the displacement in both the X and Z directions is almost zero. In type C of the bubble generating device 1, when the length of position D is 6.1 mm, the displacement in both the X and Z directions is almost zero.

[0045] Figure 9 This is a graph showing the change in the average displacement in the Z direction for each type relative to the length at position D. Figure 9 In this diagram, the vertical axis is set as the average displacement in the Z direction (unit: μm), and the horizontal axis is set as the length of position D (unit: mm). Additionally, in... Figure 9 The diagram illustrates the defined range S. The displacement of the displacement object range (the side surface of the second cylindrical body 33) within the defined range S means, for example, that the average displacement falls to approximately half of the initial value. Specifically, in... Figure 9In the example shown, the range of absolute values ​​(approximately ±0.03 μm) of the average displacement in the Z direction after halving the initial value (approximately +0.06 μm) is defined as the specified range S. The range of positions D satisfying this specified range S is approximately ±0.4 mm = approximately ±3% in the most stringent type C, and approximately ±0.7 mm = approximately ±5% in type A. The specified range S is half the displacement range without the third cylindrical body 35, but it is not limited to this; it is any range that prevents leakage of liquid from the liquid tank 10 from the junction of the liquid tank 10 and the bubble generating device 1, etc.

[0046] The positions of the third cylindrical body 35 and the counterweight 36 can also be defined from the perspective of inertial torque. The inertial torque Ia between position A and position B is the first inertial torque generated at one end of the second cylindrical body 33, and Ia = Ma(B) can be calculated. 2 -A 2 )×(1 / 2). Here, Ma includes the mass of the vibrating plate 2, the first cylindrical body 31, and the spring part 32, and is the equivalent mass considering the surface density. A and B are the coordinates of positions A and B, respectively. On the other hand, the inertial torque Ib between positions C and D is the second inertial torque generated at the other end of the second cylindrical body 33, and it can be calculated that Ib=Mb(D 2 -C 2 )×(1 / 2). Here, Mb includes the mass of the third cylindrical body 35 and the counterweight 36, which is the equivalent mass taking into account the areal density, and C and D are the coordinates of position C and position D.

[0047] The moment of inertia Ia between positions A and B does not depend on the type of bubble generating device 1, but the moment of inertia Ib between positions C and D depends on the type of bubble generating device 1. Figure 10 This is a graph showing the change in inertial torque relative to the length at position D. In Figure 10 In the diagram, the vertical axis is set as the moment of inertia (arbitrary unit ARB.), and the horizontal axis is set as the length of position D (unit mm). The moment of inertia Ia does not depend on the type of bubble generating device 1, and therefore becomes a constant value (=83565). On the other hand, the moment of inertia Ib depends on the type of bubble generating device 1, and therefore a graph is shown for each type.

[0048] from Figure 10 It can be seen that the length of the position D where the inertial moment Ia coincides with each type of inertial moment Ib is called the length of the position D that coincides with the position D of the inertial moment Ia. Figure 9The length of position D, where the displacement in the Z direction is almost zero, is close to the value shown. Specifically, the length of position D, where the inertial moments Ia and Ib coincide, is approximately 6.6 mm in type A of the bubble generating device 1, approximately 6.2 mm in type B, and approximately 5.9 mm in type C. Therefore, if the difference between the inertial moments Ia and Ib is within ±3%, then as... Figure 9 As shown, the displacement of the displacement object range (the side of the second cylindrical body 33) is within the specified range S.

[0049] Furthermore, since the change in the inertial moment Ib graph for type A is gradual, it can be inferred that the tolerance range for position D is also relatively wide. From this perspective, it is also consistent with... Figure 9 The range of position D of type A has the same trend.

[0050] This indicates that the displacement on the side of the object also varies depending on the density of the counterweight 36. Figure 11 This is a graph representing the displacement in the Z direction relative to the density of the counterweight 36. Figure 11 In this context, the vertical axis is set as the displacement in the Z direction (unit: μm), and the horizontal axis is set as the position on the side of the object (the position on the side of the second cylindrical body 33 from the spring part 32 to the flange part 34) (unit: mm). Additionally, in... Figure 11 The diagram shows that the counterweight 36 is made of Cu (density 8.93 g / cm³). 3 The counterweight part 36 is made of SUS (Steel Use Stainless) (density 7.75 g / cm³). 3 The counterweight 36 is made of hard aluminum (density 2.79 g / cm³). 3 The displacement of the object's side surface under the condition of ( ). From Figure 11 It can be seen that even if the third cylindrical body 35 and the counterweight 36 are in the same position, if the density is low, the displacement of the object's side will also be large.

[0051] As described above, the bubble generating device 1 according to this embodiment is installed in a liquid tank 10 to generate fine bubbles in the liquid in the liquid tank 10. The bubble generating device 1 includes a vibrating plate 2, a first cylindrical body 31, a spring portion 32, a second cylindrical body 33, a flange portion 34, a third cylindrical body 35, a counterweight portion 36, and a piezoelectric element 4. The vibrating plate 2 has multiple openings and is positioned such that one side contacts the liquid in the liquid tank 10, and the other side contacts the gas. The first cylindrical body 31 supports the vibrating plate 2 at one end. The spring portion 32 is plate-shaped and supports the other end of the first cylindrical body 31. The second cylindrical body 33 is located outside the position supporting the first cylindrical body 31 and supports the spring portion 32 at one end. The flange portion 34 is plate-shaped and supports the other end of the second cylindrical body 33, extending outward from the position of the second cylindrical body 33. The third cylindrical body 35 is located at one end of the flange 34, which is positioned further outward than the position supporting the second cylindrical body 33. A counterweight 36 is provided at the other end of the third cylindrical body 35. The piezoelectric element 4 causes the spring 32 to vibrate. The third cylindrical body 35 and the counterweight 36 are positioned such that the displacement of the side of the second cylindrical body 33 is within a predetermined range S when the spring 32 is vibrated by the piezoelectric element 4.

[0052] Therefore, by providing a third cylindrical body 35 and a counterweight 36 in the bubble generating device 1, the displacement of the joint with the liquid tank 10 can be adjusted to be within a specified range S, thereby preventing the liquid in the liquid tank 10 from leaking from the joint between the liquid tank 10 and the bubble generating device 1.

[0053] Furthermore, in the bubble generating device 1, the spring section 32 does not have a through hole extending from the first cylindrical body 31 to the second cylindrical body 33. This prevents light oil from leaking into the interior of the first cylindrical body 31 through the fine holes of the vibrating plate 2, thus preventing the leaked light oil from splashing onto the piezoelectric element 4 and corroding it. Instead, as... Figure 3 As shown, the spring portion 32 is provided with a connecting portion 320 for gas to flow into the first cylindrical body 31 from the side. To allow gas to flow in through the opening of this connecting portion 320, the displacement of the second cylindrical body 33, including the spring portion 32, needs to be suppressed within a predetermined range S. Furthermore, in the case where the connecting portion 320 is used to release light oil trapped at the bottom of the first cylindrical body 31 to the outside, to prevent the connection between this structure and the opening of the connecting portion 320 from being affected by the vibration of the piezoelectric element 4, the displacement of the second cylindrical body 33, including the spring portion 32, also needs to be suppressed within a predetermined range S.

[0054] The third cylindrical body 35 and the counterweight 36 are preferably positioned such that, when the spring part 32 is vibrated using the piezoelectric element 4, the difference between the first inertial torque (Ia) generated at one end of the second cylindrical body 33 and the second inertial torque (Ib) generated at the other end of the second cylindrical body 33 is a predetermined difference. Therefore, the bubble generating device 1 can adjust the displacement of the side of the second cylindrical body 33 to within a predetermined range S when the spring part 32 is vibrated using the piezoelectric element 4. In particular, the predetermined difference is preferably within ±3%.

[0055] The piezoelectric element 4 is preferably disposed in the middle of the surface of the spring portion 32 on the side supported by the second cylindrical body 33, at a position further inward than the position supported by the second cylindrical body 33. As a result, the bubble generating device 1 can efficiently transmit the vibration of the piezoelectric element 4 to the first cylindrical body 31, enabling the first cylindrical body 31 and the vibrating plate 2 to vibrate up and down in parallel.

[0056] The piezoelectric element 4 is preferably disposed on the surface of the spring portion 32 on the side supported by the second cylindrical body 33, covering the entire inner diameter of the second cylindrical body 33. This allows for more efficient generation of fine bubbles.

[0057] (Variation Example 1)

[0058] In the bubble generating apparatus 1 described in the above embodiment, the spring portion 32 is described as plate-shaped, but the end of the spring portion 32 can also be machined into a conical shape. This is because there are many cases where there is a large displacement and tilt at the edge, and by forming a conical shape, a retaining plate can be formed in the part with less displacement and tilt inside. Providing two retaining portions on the side portion can improve the retaining strength and doubly prevent liquid leakage, or when introducing gas into the space portion, a retaining portion can be provided in this conical portion. Figure 12 This diagram shows an example of machining the end of the spring into a tapered shape. Furthermore, regarding... Figure 12 The bubble generating device 1a shown in the figure has the same characteristics as the bubble generating device 1a shown in the figure. Figure 3 The bubble generating device 1 shown has the same structure and is labeled with the same reference numerals in the accompanying drawings, and detailed descriptions will not be repeated.

[0059] like Figure 12 As shown, the spring portion 32a has its end machined into a tapered shape 32b. (As...) Figure 12 As shown, by machining the corner of the end of the spring portion 32a near the vibrating plate 2 into a conical shape 32b, the vibration of the piezoelectric element 4 can be made less susceptible to damping by the spring portion 32a.

[0060] (Variation Example 2)

[0061] like Figure 1As shown, the second cylindrical body 33 may also be provided with a protrusion 33a, which is connected to the liquid tank 10. As a result, in the bubble generating system 100 equipped with the bubble generating device 1 and the liquid tank 10, the airtightness of the bubble generating device 1 and the liquid tank 10 is improved.

[0062] All points in the embodiments disclosed herein are merely illustrative and should not be considered as limitations on the invention. The scope of the invention is defined by the claims rather than by the foregoing description, and includes all modifications within the meaning and scope equivalent to the claims.

[0063] Explanation of reference numerals in the attached figures

[0064] 1, 1a...bubble generating device; 2...vibrating plate; 3...cylindrical body; 4...piezoelectric element; 10...liquid tank; 20...controller; 31...first cylindrical body; 32...spring part; 33...second cylindrical body; 33a...protrusion; 34...flange part; 35...third cylindrical body; 36...counterweight part; 100...bubble generating system; 200...bubble.

Claims

1. A bubble generating device, which is installed in a liquid tank to generate fine bubbles in the liquid in the liquid tank, wherein... have: The vibrating plate has multiple openings and is positioned such that one side is in contact with the liquid in the liquid tank and the other side is in contact with the gas. The first cylindrical body supports one end of the vibrating plate; A plate-shaped spring section supports the other end of the first cylindrical body; The second cylindrical body has one end that supports the spring portion at a position located further outward than the position supporting the first cylindrical body; The plate-shaped flange supports the other end of the second cylindrical body and extends outward from the position of the second cylindrical body. The third cylindrical body is located at one end of the flange portion that supports the flange portion at a position that is further outward than the position supporting the second cylindrical body; A counterweight is disposed at the other end of the third cylindrical body; as well as A piezoelectric element is disposed on the surface of the spring portion supported by the second cylindrical body, causing the spring portion to vibrate. The third cylindrical body and the counterweight are positioned such that the displacement of the side of the second cylindrical body is within a specified range when the spring part is vibrated by the piezoelectric element.

2. The bubble generating device according to claim 1, wherein, The third cylindrical body and the counterweight are positioned such that, when the spring is vibrated by the piezoelectric element, the difference between the first inertial torque generated at one end of the second cylindrical body and the second inertial torque generated at the other end of the second cylindrical body is a predetermined difference.

3. The bubble generating device according to claim 2, wherein, The specified deviation is within ±3%.

4. The bubble generating apparatus according to any one of claims 1 to 3, wherein, The piezoelectric element is disposed on the side of the spring portion supported by the second cylindrical body, at a position more inward than the position supported by the second cylindrical body.

5. The bubble generating apparatus according to any one of claims 1 to 3, wherein, The piezoelectric element is disposed on the surface of the spring portion on the side supported by the second cylindrical body, covering the entire inner diameter of the second cylindrical body.

6. A bubble generating system, wherein, have: The bubble generating apparatus according to any one of claims 1 to 5; and The liquid tank.

7. The bubble generating system according to claim 6, wherein, The bubble generating device is connected to the liquid tank on the side of the second cylindrical body.

Images