Fine bubble generator, processing liquid supply device, and substrate processing device.

Abstract

This technology provides a way to stabilize the fine bubble generation efficiency even when the flow rate fluctuates. [Solution] The fine bubble generator (1) comprises a first pipe section (21), a constricted pipe section (23), a constricted pipe section 24, a swirling flow forming section (26), and a variable mechanism (27). The constricted pipe section (23) is located downstream of the first pipe section (21). The constricted pipe section (24) is located between the first pipe section (21) and the second pipe section (23) and has a narrowing section (241) in which the flow path cross-sectional area decreases towards the downstream. The swirling flow forming section (26) forms a swirling flow path (40), which is a flow path for swirling liquid, in or upstream of the narrowing section (241). The variable mechanism (27) changes the flow path cross-sectional area of ​​the swirling flow path (40) according to the flow rate of the first pipe section (21).

Description

Technical Field

[0005] ,

[0001] The subject matter disclosed in this specification relates to a fine bubble generator, a processing liquid supply device, and a substrate processing device.

Background Art

[0002] Conventionally, a generator for generating fine bubbles (microbubbles) has been known. For example, in the device of Patent Document 1, a narrow gap and a gradually expanding region are continuously provided in a flow path through which a liquid flows. In this device, the flow rate is increased by restricting the liquid flow in the narrow gap, and a lower pressure is generated compared to the low-speed part of the liquid flow. Then, by releasing the pressure of the liquid flow in the gradually expanding region immediately after the narrow gap, microbubbles on the order of micro or nano are generated from the bubbles mixed in the water. Further, Patent Document 1 also describes changing the bubble size by further narrowing the interval of the narrow gap.

[0003] Further, Patent Document 2 describes passing a liquid through a vortex collapse nozzle having a constriction part where the cross-sectional area gradually decreases and a vortex collapse part that expands toward the downstream side by swirling the liquid. By generating a swirling flow, when the liquid flows into the vortex collapse nozzle, the bubbles are finely crushed and fine microbubbles are generated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in conventional fine bubble generators, fluctuations in liquid flow rate can lead to changes in the flow velocity of the swirling flow and the pressure on the liquid, potentially reducing the efficiency of fine bubble generation. For example, to efficiently generate fine bubbles, it is desirable to maintain a suitable swirling speed in the swirling flow section. However, the swirling speed increases or decreases in response to increases or decreases in flow rate, making it difficult to stably generate fine bubbles.

[0006] The object of the present invention is to provide a technology that can stabilize the fine bubble generation efficiency even when the flow rate fluctuates. [Means for solving the problem]

[0007] To solve the above problems, the first embodiment is a fine bubble generator comprising: a first pipe section; a second pipe section located downstream of the first pipe section; a narrowed pipe section located between the first pipe section and the second pipe section and having a narrowing section in which the flow path cross-sectional area decreases toward the downstream direction; a swirling flow forming section that forms a swirling flow path, which is a flow path for a swirling liquid, in the narrowing section or upstream of the narrowing section; and a variable mechanism that changes the flow path cross-sectional area of ​​the swirling flow path according to the flow rate of the first pipe section. A valve housing located between the first pipe section and the second pipe section and having a first inlet to which the first pipe section is connected, and a branch pipe section that branches off in the middle of the first pipe section and is connected to a second inlet of the valve housing, Equipped with The swirling flow forming section has a first valve body disposed within the valve housing, and the variable mechanism has a reciprocating drive unit that moves the first valve body forward and backward relative to the narrowing section according to the flow rate of the first pipe section, and the swirling flow path is formed between the first valve body and the narrowing section, and the reciprocating drive unit has a diaphragm connected to the first valve body that deforms to move the first valve body according to the flow rate of the first pipe section, and a biasing unit that biases the first valve body connected to the diaphragm toward the narrowed pipe section, and the second inlet is located closer to the diaphragm than the first inlet. .

[0011] The 2 The aspect is, 1 A fine bubble generator of the present invention, wherein the swirling flow forming section further comprises a second valve body that partially closes the first inlet, and the variable mechanism changes the opening area of ​​the first inlet by moving the second valve body according to the flow rate of the first pipe section.

[0012] The 3 The aspect is, 2 The fine bubble generator of the present invention is configured such that the first inlet is located at a position radially offset with respect to the central axis of the valve housing.

[0013] centre It is a fine bubble generator, The device comprises a first pipe section, a second pipe section located downstream of the first pipe section, a constricted pipe section located between the first and second pipe sections and having a narrowing section in which the flow path cross-sectional area decreases toward the downstream direction, a swirling flow forming section that forms a swirling flow path, which is a flow path for a swirling liquid, in the narrowing section or upstream of the narrowing section, and a variable mechanism that changes the flow path cross-sectional area of ​​the swirling flow path according to the flow rate of the first pipe section. The swirling flow forming section includes a first cylindrical section formed in the shape of a cylinder extending in the axial direction, a second cylindrical section formed in the shape of a cylinder extending in the axial direction and inserted inside the first cylindrical section, and a forward / backward drive section that moves the first cylindrical section relative to the second cylindrical section according to the flow rate of the first pipe section, wherein the swirling flow path is formed between the first cylindrical section and the second cylindrical section, and at least one of the inner circumferential surface of the first cylindrical section or the outer circumferential surface of the second cylindrical section is inclined radially with respect to the axial direction.

[0014] The 5 The embodiment is a processing liquid supply device comprising a fine bubble generator according to the first or second embodiment, and a supply unit that supplies a processing liquid containing fine bubbles generated by the fine bubble generator to an object to be processed.

[0015] The 6 The embodiment is a substrate processing apparatus comprising: a support section for supporting a substrate; a fine bubble generator according to the first or second embodiment; and a supply section for supplying a processing liquid containing fine bubbles generated by the fine bubble generator to the substrate supported by the support section. [Effects of the Invention]

[0016] From the first aspect to the 6 condition To Mr. Therefore, by changing the flow path cross-sectional area of ​​the swirling channel according to the flow rate of the first pipe section, it is possible to maintain a swirling speed suitable for fine bubble generation even when the flow rate fluctuates. As a result, the fine bubble generation efficiency can be stabilized.

[0017] The 1 manner From the third aspect According to the fine bubble generator, the flow path cross-sectional area of ​​the swirling flow path between the first valve body and the shrinking section can be changed by moving the first valve body forward and backward relative to the shrinking section in accordance with the flow rate of the first pipe section.

[0018] The 1 manner From the third aspectAccording to the fine bubble generator, the valve body can be moved by the deformation of the diaphragm. Further, the urging portion can urge the first valve body that has moved in a direction away from the narrow pipe portion to return to a specified position.

[0019] First 1 Aspect From the third aspect According to the fine bubble generator of this aspect, the diaphragm can be deformed by the pressure of the liquid flowing in from the branch pipe portion.

[0020] First 2 According to the fine bubble generator of this aspect, by changing the opening area of the first inlet according to the flow rate, a flow velocity and pressure suitable for forming a swirling flow can be obtained.

[0021] First 3 According to the fine bubble generator of this aspect, by arranging the first inlet offset from the central axis, the liquid flowing in from the first inlet can be swirled inside the valve housing.

[0022] First 4 According to the fine bubble generator of this aspect, by moving the first cylindrical portion with respect to the second cylindrical portion, the cross-sectional area of the swirling flow path can be changed.

Brief Description of the Drawings

[0023] [Figure 1] It is a diagram showing a cleaning device provided with a fine bubble generator according to the first embodiment. [Figure 2] It is a schematic cross-sectional view showing a fine bubble generator according to the first embodiment. [Figure 3] It is a schematic cross-sectional view of the fine bubble generator at the position of the A-A line shown in FIG. 2. [Figure 4] It is a schematic cross-sectional view showing the fine bubble generator when the flow rate of the first pipe portion increases. [Figure 5] It is a schematic cross-sectional view showing a fine bubble generator according to the second embodiment.

Modes for Carrying Out the Invention

[0024] Embodiments of the present invention will be described below with reference to the attached drawings. Note that in the drawings, the dimensions and number of parts may be exaggerated or simplified for ease of understanding.

[0025] <1. First Embodiment> Figure 1 shows a cleaning apparatus 100 equipped with a fine bubble generator 1 according to the first embodiment. The cleaning apparatus 100 is a device for cleaning a substrate W with cleaning water. The substrate W is supported by, for example, a transport roller (not shown) and moves continuously in one direction horizontally by the transport roller. The transport roller corresponds to a support part that supports the substrate.

[0026] The cleaning device 100 includes a supply unit 10. The supply unit 10 includes a high-pressure nozzle 11, a supply pipe 13, a pump 15, a tank 17, and a control unit 19. The high-pressure nozzle 11 has a spray pipe 111 and a plurality of nozzle sections 113. The spray pipe 111 extends in a direction perpendicular to the transport direction of the substrate W. Cleaning water is supplied to the spray pipe 111. The plurality of nozzle sections 113 are arranged at equal intervals along the spray pipe 111. Each nozzle section 113 is designed to spray the cleaning water supplied from the spray pipe 111 at high pressure while dispersing it.

[0027] The supply pipe 13 supplies cleaning water to the high-pressure nozzle 11. The supply pipe 13 connects the tank 17 to the spray pipe 111 of the high-pressure nozzle 11, and the pump 15 supplies cleaning water to the high-pressure nozzle 11. The tank 17 stores the cleaning water supplied to the supply pipe 13. Alternatively, the cleaning water used to clean the substrate W may be collected in the tank 17, thereby circulating the cleaning water.

[0028] The fine bubble generator 1 is positioned, for example, in the middle of the supply piping 13. The fine bubble generator 1 is capable of generating fine bubbles with a diameter of less than 100 μm (micrometers), and in particular, it is capable of generating ultrafine bubbles. Among fine bubbles, bubbles with a diameter of less than 100 μm and 1 μm or more are called microbubbles, and bubbles with a diameter of less than 1 μm are called ultrafine bubbles. Fine bubbles are more stable than ordinary bubbles and can remain in liquid for a long time. Among fine bubbles, ultrafine bubbles are considered particularly useful in cleaning effects and other applications.

[0029] As shown in Figure 1, the cleaning water containing fine bubbles generated in the fine bubble generator 1 is sent to the high-pressure nozzle 11 through the supply pipe 13. Then, the cleaning water containing fine bubbles is supplied to the substrate W from each nozzle section 113 of the high-pressure nozzle 11. As a result, the substrate W can be cleaned with cleaning water containing fine bubbles, thus achieving a high cleaning effect. In addition, the amount of cleaning water consumed can be reduced, thereby reducing the environmental impact.

[0030] It is not mandatory for the fine bubble generator 1 to be installed in the supply piping 13. For example, the fine bubble generator 1 may be installed in piping for supplying the treated liquid to the tank 17.

[0031] The supply unit 10 supplies a processing liquid (washing water) containing fine bubbles generated by the fine bubble generator 1 to the object to be processed (substrate W). The apparatus comprising the fine bubble generator 1 and the supply unit 10 corresponds to a "processing liquid supply apparatus". Furthermore, the washing apparatus 100 comprising a support unit (transport roller) for supporting the substrate, the fine bubble generator 1, and the supply unit 10 corresponds to a "substrate processing apparatus".

[0032] <Fine bubble generator> Figure 2 is a schematic cross-sectional view showing a fine bubble generator 1 according to the first embodiment. The white block arrows shown in Figure 2 and subsequent figures indicate the direction of liquid flow. As shown in Figure 2, the fine bubble generator 1 comprises a first pipe section 21, a second pipe section 23, a constricted pipe section 24, a valve housing 25, a swirling flow forming section 26, and a variable mechanism 27. The first pipe section 21 is located at the upstream end of the fine bubble generator 1. The second pipe section 23 is located downstream of the first pipe section 21. The upstream side of the first pipe section 21 is connected to a supply pipe 13 in a cleaning device 100, for example. The downstream side of the second pipe section 23 is also connected to a supply pipe 13, for example. The constricted pipe section 24 is located between the first pipe section 21 and the second pipe section 23. The downstream side of the constricted pipe section 24 is connected to the second pipe section 23 via a flow path. The upstream side of the constricted pipe section 24 is connected to the first pipe section 21 via a valve housing 25 via a flow path.

[0033] The constricted pipe section 24 has a narrowing section 241, an intermediate section 242, and an expanding section 243. The narrowing section 241 is a section in which the inner diameter (inner width) gradually decreases toward the downstream side. In other words, the narrowing section 241 is a section in which the cross-sectional area of ​​the flow path decreases. The intermediate section 242 is connected to the flow path downstream of the narrowing section 241 and is a section in which the inner diameter (inner width) is almost constant toward the downstream side. The expanding section 243 is connected to the flow path downstream of the intermediate section 242 and is a section in which the inner diameter (inner width) gradually increases toward the downstream side. The second pipe section 23 is connected to the flow path downstream of the expanding section 243.

[0034] The valve housing 25 connects the first pipe section 21 and the constricted pipe section 24. The first pipe section 21 is connected to a first inlet P1 provided in the valve housing 25.

[0035] The valve housing 25, the constricted pipe section 24, and the second pipe section 23 are arranged coaxially with respect to axis A1. In the following description, the direction parallel to axis A1 is referred to as the "axial direction." In the axial direction, the direction from the constricted pipe section 24 toward the second pipe section 23 is referred to as "one axial direction," and the opposite direction is referred to as "the other axial direction." The direction perpendicular to axis A1 is referred to as the "radial direction." In the radial direction, the direction approaching axis A1 is referred to as "radial inward," and the direction moving away from axis A1 is referred to as "radial outward." The direction of rotation around axis A1 is referred to as the "circumferential direction."

[0036] The constricted pipe section 24 is connected to the flow path at one axial end of the valve housing 25. The inner diameter (inner width) of the second pipe section 23 is greater than the minimum value of the inner diameter (inner width) of the constricted pipe section 24. Also, the inner diameter (inner width) of the second pipe section 23 is greater than the inner diameter (inner width) of the first pipe section 21.

[0037] At the inlet side of the constricted pipe section 24, the flow velocity of the liquid increases as the cross-sectional area of ​​the flow path decreases. As the flow velocity increases, the pressure on the liquid decreases according to Bernoulli's principle. Therefore, the liquid pressure drops sharply in the constricted pipe section 24. When the pressure drops, gases (such as air) dissolved in the liquid precipitate as bubbles (cavitation). In the constricted pipe section 24, this pressure drop generates a large number of tiny bubbles.

[0038] Furthermore, at the outlet side of the constricted pipe section 24, the flow path cross-sectional area increases again, reducing the liquid flow velocity and returning the liquid pressure to its original level. This return of pressure causes the bubbles generated in the constricted pipe section 24 to shrink. In other words, the diameter of the bubbles becomes very small. As a result, fine bubbles with a diameter of 1 μm or less are formed.

[0039] Although not shown in the diagram, a pipe (not shown) for supplying gas to the liquid may be provided at or upstream of the constricted pipe section 24. By supplying gas to the liquid in the pipe, the amount of fine bubbles generated can be increased.

[0040] The swirling flow forming section 26 forms a swirling flow path 40 in the narrowed section 241 of the constricted pipe section 24 and upstream of it. The swirling flow path 40 is a flow path for liquid that moves axially (in this case, in one axial direction) while swirling around axis A1. The swirling flow forming section 26 has a shaft section 30, a first valve body 31, and a second valve body 32. The shaft section 30, the first valve body 31, and the second valve body 32 are arranged inside the valve housing 25. The shaft section 30 is a rod-shaped member that extends along the axial direction. The other axial end of the shaft section 30 is fixed to a diaphragm 331, which will be described later. The first valve body 31 and the second valve body 32 are fixed to the axial end of the shaft section 30.

[0041] The first valve body 31 is formed in a tapered shape, with its outer diameter (outer width) gradually decreasing as it moves in one axial direction. The first valve body 31 is supported so as to be movable in the axial direction with respect to the valve housing 25 and the constricted pipe section 24. The first valve body 31 forms a swirling flow path 40 between itself and the narrowed portion 241 of the constricted pipe section 24.

[0042] The second valve body 32 is movable axially together with the first valve body 31. The second valve body 32 is located on the other axial side relative to the first valve body 31. The second valve body 32 changes the opening area of ​​the first inlet P1 by partially closing the first inlet P1 while moving axially. More specifically, the second valve body 32 has a circular plate-shaped flange portion 321 that extends radially from the shaft portion 30, and an annular (here, circular ring) ring portion 323 that protrudes axially from the peripheral edge of the flange portion 321 to the other side. The first valve body 31 is located on one axial side surface of the flange portion 321. The ring portion 323 partially closes the first inlet P1 by overlapping it radially with the first inlet P1. In addition, the opening area of ​​the first inlet P1 is changed as the ring portion 323 moves axially.

[0043] When the flow rate of the first pipe section 21 is sufficiently small, as shown in Figure 2, the ring portion 323 of the second valve body 32 overlaps with the opening on the other axial side of the first inlet P1. Therefore, the first pipe section 21 communicates with the valve housing 25 through the opening on one axial side of the first inlet P1. As will be described later, when liquid is supplied to the fine bubble generator 1, the ring portion 323 moves to the other axial side in accordance with the flow rate of the first pipe section 21, and the opening area of ​​the first inlet P1 increases.

[0044] The variable mechanism 27 is located within the valve housing 25. The variable mechanism 27 changes the flow path cross-sectional area of ​​the swirling flow path 40 according to the flow rate of the liquid in the first pipe section 21. The variable mechanism 27 has a forward / backward drive unit 33.

[0045] The forward / backward drive unit 33 moves the first valve body 31 and the second valve body 32 forward and backward relative to the narrowed portion 241 of the constricted pipe section 24, according to the flow rate of the liquid in the first pipe section 21. The forward / backward drive unit 33 has a diaphragm 331 and a biasing portion 332. The diaphragm 331 and the biasing portion 332 are located on the opposite axial side relative to the first valve body 31 and the second valve body 32.

[0046] The valve housing 25 has a widened portion 252. The inner diameter (inner width) of the widened portion 252 is larger than the inner diameter (inner width) of the portion of the valve housing 25 in which the first valve body 31 and the second valve body 32 are housed. The widened portion 252 is also located axially away from the first inlet P1. The circumferential end of the diaphragm 331 is fixed to the inner circumferential surface of the widened portion 252, and the diaphragm 331 is deformable axially within the widened portion 252. The end of the shaft portion 30 is fixed to the center of the diaphragm 331. The diaphragm 331 deforms to indent in the other axial direction according to the flow rate of the liquid flowing from the first pipe portion 21 into the valve housing 25. This deformation causes the first valve body 31 and the second valve body 32 to move in the other axial direction.

[0047] The biasing portion 332 is a member for biasing the first valve body 31 and the second valve body 32 toward the constricted pipe portion 24. For example, if the first valve body 31 and the second valve body 32 move axially to the other side from a specified position, the biasing portion 332 presses the first valve body 31 and the second valve body 32 back to their original specified positions. The biasing portion 332 is an elastic body, such as a coil spring, which is arranged to expand and contract axially. The biasing portion 332 is located axially to the other side of the diaphragm 331. One axial end of the biasing portion 332 is fixed to the diaphragm 331. That is, the biasing portion 332 biases the first valve body 31 and the second valve body 32 via the diaphragm 331 and the shaft portion 30.

[0048] The other axial end of the biasing portion 332 is fixed to an adjustment screw 253. The adjustment screw 253 is attached to the other axial end of the valve housing 25. The screw groove of the adjustment screw 253 engages with a screw hole provided in the valve housing 25, and by rotating the adjustment screw 253 around axis A1, the adjustment screw 253 moves in the axial direction. By adjusting the position of the adjustment screw 253, the positions of the biasing portion 332 and the diaphragm 331 are adjusted. This makes it possible to adjust the positions of the first valve body 31 and the second valve body 32 in the axial direction.

[0049] The forward / backward drive unit 33 has a bearing unit 334. The bearing unit 334 supports the shaft 30 of the swirling flow forming unit 26 so that it can move axially relative to the valve housing 25 and the constricted pipe section 24. The bearing unit 334 has a cylindrical portion fixed to the valve housing 25, through which the shaft 30 passes. By moving the shaft 30 axially while being supported by the bearing unit 334, vibration and rattle of the first valve body 31 and the second valve body 32 can be suppressed.

[0050] Figure 3 is a schematic cross-sectional view of the fine bubble generator 1 at the position indicated by line AA in Figure 2. As shown in Figure 3, the first inlet P1 is positioned laterally (radially) offset from axis A1 (the central axis of the valve housing). That is, the first pipe section 21 is connected to the valve housing 25 in a flow path at a position radially offset from the central axis. Therefore, the liquid flowing from the first pipe section 21 into the valve housing 25 moves axially to one side (downstream) in the swirling flow path 40 around the first valve body 31 while spiraling around axis A1. By swirling the liquid in this way, centrifugal force is generated, creating pressure differences and allowing gaseous components to be concentrated in the center of the swirl (axis A1), thus enabling efficient generation of fine bubbles in the constricted pipe section 24.

[0051] The fine bubble generator 1 is equipped with a branch pipe section 29. The branch pipe section 29 is a pipe that branches off from the first pipe section 21 and is connected to the valve housing 25 via a flow path. With respect to the valve housing 25, the branch pipe section 29 is connected to a second inlet P2 provided in the widened section 252 of the valve housing 25. The second inlet P2 is located closer to the diaphragm 331 in the axial direction than the first inlet P1. The second inlet P2 is located further axially from the constricted pipe section 24 than the first inlet P1. The second inlet P2 is also located further axially from the diaphragm 331 on one side (i.e., the side closer to the constricted pipe section 24). Furthermore, the second inlet P2 is located on the other side in the axial direction from the second valve body 32 and the bearing section 334. Liquid flows into the space partitioned by the diaphragm 331 in the widened section 252 from the branch pipe section 29 via the second inlet P2.

[0052] Figure 4 is a schematic cross-sectional view showing the fine bubble generator 1 when the flow rate in the first pipe section 21 increases. When the flow rate in the first pipe section 21 increases, as shown in Figure 4, the amount of liquid attempting to flow from the branch pipe section 29 into the widened section 252 of the valve housing 25 increases, and the water pressure in the widened section 252 rises. As a result, the diaphragm 331 deforms in a direction away from the constricted pipe section 24 (the other axial direction), and the first valve body 31 and the second valve body 32 move in a direction away from the reduced section 241 of the constricted pipe section 24 (the other axial direction). This increases the gap between the reduced section 241 and the first valve body 31. In other words, the flow path cross-sectional area in the swirling flow path 40 increases in accordance with the increase in the flow rate in the first pipe section 21. By increasing the flow path cross-sectional area, the pressure loss in the swirling flow path 40 can be reduced, thus mitigating the decrease in flow velocity. Therefore, a decrease in the fine bubble generation efficiency can be suppressed.

[0053] Furthermore, as the flow rate in the first pipe section 21 increases, the second valve body 32, along with the first valve body 31, moves axially to the other side, thereby increasing the opening area of ​​the first inlet P1. This suppresses the increase in flow velocity at the first inlet P1, and thus stabilizes the flow velocity of the swirling flow.

[0054] When the flow rate in the first pipe section 21 decreases, as shown in Figure 2, the amount of liquid attempting to flow from the branch pipe section 29 into the widened section 252 decreases, and the water pressure in the widened section 252 decreases. As a result, the restoring force of the biasing section 332 causes the diaphragm 331, which had been deformed to one side in the axial direction, to return to its original shape, and the first valve body 31 is brought closer to the narrowed section 241 of the constricted pipe section 24. This reduces the gap between the narrowed section 241 and the first valve body 31, and the cross-sectional area of ​​the swirling flow path 40 decreases. As a result, even if the flow rate in the swirling flow path 40 decreases, the fluid can be swirled at high speed in a narrow space, thus maintaining a high efficiency in generating fine bubbles.

[0055] Furthermore, when the flow rate in the first pipe section 21 decreases, the second valve body 32, along with the first valve body 31, moves axially to one side, thereby reducing the opening area of ​​the first inlet P1. This suppresses the decrease in flow velocity at the first inlet P1, allowing the required swirling speed to be maintained. As a result, even when the flow rate in the first pipe section 21 decreases, the fine bubble generation efficiency can be maintained at a high level.

[0056] As described above, according to the fine bubble generator 1 of this embodiment, the size of the flow path cross-sectional area of ​​the swirling flow path 40 is automatically increased or decreased in accordance with the increase or decrease in the flow rate of the first pipe section 21. Therefore, fluctuations in the liquid pressure and flow velocity in the constricted pipe section 24 can be reduced, and the fine bubble generation efficiency can be stabilized even when the flow rate fluctuates.

[0057] <2. Second Embodiment> Next, a second embodiment will be described. In the following description, elements having the same function as those already described will be given the same reference numeral or a reference numeral with an additional alphabetic character, and detailed descriptions may be omitted.

[0058] Figure 5 is a schematic cross-sectional view showing a fine bubble generator 1A according to the second embodiment. The fine bubble generator 1A differs from the fine bubble generator 1 mainly in that the swirling flow channel 40a formed by the swirling flow forming section 26a extends in a meandering manner along the axial direction.

[0059] The swirling flow forming section 26a has a movable cylindrical section 35 (first cylindrical section). The movable cylindrical section 35 is a cylindrical member that extends axially with axis A1 as its central axis. The inner circumferential surface of the movable cylindrical section 35 is inclined radially outward with a constant inclination toward one side in the axial direction. A first valve body 31a is positioned radially inside the movable cylindrical section 35. The first valve body 31a is formed in a cylindrical shape with a substantially constant outer diameter (outer width) and extends axially toward one side from the flange section 321 of the second valve body 32. The other end of the movable cylindrical section 35 in the axial direction is fixed to the flange section 321 of the second valve body 32. Therefore, the movable cylindrical section 35 is movable axially together with the first valve body 31a and the second valve body 32.

[0060] The fine bubble generator 1A includes a fixed cylindrical section 51 (second cylindrical section). The fixed cylindrical section 51 is located at the other axial end of the constricted pipe section 24 and is provided to be continuous with the other axial side of the reduction section 241 of the constricted pipe section 24. The fixed cylindrical section 51 is inserted radially inward of the movable cylindrical section 35. The outer circumferential surface of the fixed cylindrical section 51 is inclined radially outward with a constant inclination toward one axial side. That is, the outer circumferential surface of the fixed cylindrical section 51 is inclined in a direction corresponding to the inclination direction of the inner circumferential surface of the movable cylindrical section 35. The inner circumferential surface of the movable cylindrical section 35 and the outer circumferential surface of the fixed cylindrical section 51 face each other with a gap between them. Note that the inclination angle of the outer circumferential surface of the fixed cylindrical section 51 does not have to match the inclination angle of the inner circumferential surface of the movable cylindrical section 35.

[0061] The swirling flow path 40a formed by the swirling flow forming section 26a includes, in order from upstream to downstream, a first swirling flow path 41, a second swirling flow path 42, and a third swirling flow path 43. The first swirling flow path 41 is an annular flow path between the valve housing 25a and the movable cylindrical section 35. The second swirling flow path 42 is an annular flow path between the movable cylindrical section 35 and the fixed cylindrical section 51. Furthermore, the third swirling flow path 43 is an annular flow path between the fixed cylindrical section 51 and the first valve body 31a.

[0062] The liquid that flows from the first pipe section 21 through the first inlet P1 into the valve housing 25a first flows axially in one direction while swirling through the first swirling passage 41 outside the movable cylindrical section 35. Subsequently, the liquid flows axially in the other direction while swirling through the second swirling passage 42 between the movable cylindrical section 35 and the fixed cylindrical section 51. Furthermore, the liquid flows axially in one direction while swirling through the third swirling passage 43 inside the fixed cylindrical section 51 and flows into the contraction section 241. In this way, with the fine bubble generator 1A, since the swirling passage 40a is formed so that the liquid meanders in the axial direction, a long swirling flow can be formed within a space limited in the axial direction.

[0063] Since the inner surface of the movable cylindrical portion 35 and the outer surface of the fixed cylindrical portion 51 are inclined radially with respect to the axial direction, moving the movable cylindrical portion 35 axially allows the movable cylindrical portion 35 and the fixed cylindrical portion 51 to move closer together or further apart radially. Therefore, the movement of the movable cylindrical portion 35 can increase or decrease the cross-sectional area of ​​the second swirling flow path 42 between the movable cylindrical portion 35 and the fixed cylindrical portion 51. It is not essential that both the inner surface of the movable cylindrical portion 35 and the outer surface of the fixed cylindrical portion 51 are inclined radially with respect to the axial direction; at least one of them must be inclined.

[0064] Furthermore, by inclining the inner circumferential surface of the movable cylindrical portion 35 (or the outer circumferential surface of the fixed cylindrical portion 51) radially inward toward the downstream side (i.e., the other axial side), a swirling flow directed radially inward can be formed in the second swirling flow path 42.

[0065] In the fine bubble generator 1A, when the flow rate of the first pipe section 21 increases, the movable cylindrical section 35 moves axially to the other side together with the first valve body 31a, causing the movable cylindrical section 35 to move away from the fixed cylindrical section 51. As a result, the cross-sectional area of ​​the second swirling flow path 42 between the movable cylindrical section 35 and the fixed cylindrical section 51 increases. Therefore, even if the flow rate increases, the pressure loss can be reduced, and thus the decrease in swirling speed can be mitigated. Consequently, a decrease in the fine bubble generation efficiency can be suppressed.

[0066] Furthermore, when the flow rate of the first pipe section 21 decreases, the biasing force of the biasing section 332 causes the movable cylindrical section 35 to move axially to one side together with the first valve body 31a, and the movable cylindrical section 35 approaches the fixed cylindrical section 51. As a result, the cross-sectional area of ​​the flow path of the second swirling flow path 42 formed by the movable cylindrical section 35 and the fixed cylindrical section 51 becomes smaller. Therefore, a swirling speed that can efficiently generate fine bubbles, which can swirl the fluid at high speed in a narrow space, can be easily obtained.

[0067] As described above, with the fine bubble generator 1A, the cross-sectional area of ​​the swirling channel 40a (second swirling channel 42) is automatically increased or decreased in accordance with the increase or decrease in the flow rate of the first pipe section 21. Therefore, even when the liquid flow rate fluctuates, the fine bubble generation efficiency can be stabilized.

[0068] <3. Variant Example> Although embodiments have been described above, the present invention is not limited to those described above, and various modifications are possible.

[0069] For example, in the fine bubble generator 1 of the first embodiment, the first valve body 31 and the second valve body 32 are configured to move integrally by a common forward / backward drive unit 33. However, the first valve body 31 and the second valve body 32 may each be configured to move independently by separate forward / backward drive units. Similarly, in the second embodiment, the first valve body 31, the second valve body 32, and the movable cylindrical part 35 may each be configured to move independently by separate forward / backward drive units.

[0070] Although this invention has been described in detail, the above description is illustrative in all respects, and the invention is not limited thereto. It is understood that countless variations not illustrated can be conceived without falling outside the scope of this invention. The components described in each of the above embodiments and variations can be combined or omitted as appropriate, as long as they do not contradict each other. [Explanation of Symbols]

[0071] 1.1A: Fine bubble generator 10: Supply section 21: First Section 23: Second Section 24: Stenotic tube part 25,25a: Valve housing 26,26a: Swirling flow forming part 27: Variable mechanism 29: Branch pipe section 31: First valve body 32: Second valve body 33: Reverse drive unit 35: Movable cylindrical part (first cylindrical part) 40,40a: Swirling flow path 42: Second swirling channel 51: Fixed cylindrical section (second cylindrical section) 100: Cleaning equipment (substrate processing equipment) 241 :Reduced part 331: Diaphragm 332: Encouraging part P1: 1st inlet P2: 2nd inlet W: Circuit board

Claims

1. It is a fine bubble generator, The first pipe section and, A second pipe section located downstream of the first pipe section, A narrowed pipe section located between the first pipe section and the second pipe section, having a narrowing section in which the cross-sectional area of ​​the flow path decreases toward the downstream direction, A swirling flow forming section is provided in the reduced portion or upstream of the reduced portion, which forms a swirling flow path that is a flow path for a swirling liquid. A variable mechanism that changes the flow path cross-sectional area of ​​the swirling flow path according to the flow rate of the first pipe section, A valve housing located between the first pipe section and the second pipe section, having a first inlet to which the first pipe section is connected, A branch pipe section that branches off midway through the first pipe section and is connected to the second inlet of the valve housing, Equipped with, The swirling flow forming section has a first valve body disposed within the valve housing, The variable mechanism has a reciprocating drive unit that moves the first valve body forward and backward relative to the retraction unit according to the flow rate of the first pipe section. The swirling flow path is formed between the first valve body and the shrinking portion. The aforementioned reciprocating drive unit is A diaphragm connected to the first valve body, which deforms to move the first valve body according to the flow rate of the first pipe section, A biasing part that biases the first valve body connected to the diaphragm toward the constricted pipe portion, It has, The second inlet is located closer to the diaphragm than the first inlet, and is a fine bubble generator.

2. A fine bubble generator according to claim 1, The swirling flow forming section further includes a second valve body that partially closes the first inlet, The variable mechanism is a fine bubble generator that changes the opening area of ​​the first inlet by moving the second valve body according to the flow rate of the first pipe section.

3. A fine bubble generator according to claim 2, The first inlet is located at a position radially offset from the central axis of the valve housing, in the fine bubble generator.

4. A fine bubble generator, The first pipe section and, A second pipe section located downstream of the first pipe section, A narrowed pipe section located between the first pipe section and the second pipe section, having a narrowing section in which the cross-sectional area of ​​the flow path decreases toward the downstream direction, A swirling flow forming section is provided in the reduced portion or upstream of the reduced portion, which forms a swirling flow path that is a flow path for a swirling liquid. A variable mechanism that changes the flow path cross-sectional area of ​​the swirling flow path according to the flow rate of the first pipe section, Equipped with, The swirling flow forming section is, A first cylindrical portion formed in a cylindrical shape extending in the axial direction, It is formed in a cylindrical shape extending in the axial direction, and a second cylindrical portion is inserted inside the first cylindrical portion, A forward and backward drive unit moves the first cylindrical section relative to the second cylindrical section according to the flow rate of the first pipe section, It has, The swirling flow path is formed between the first cylindrical portion and the second cylindrical portion. A fine bubble generator in which at least one of the inner surface of the first cylindrical portion or the outer surface of the second cylindrical portion is inclined radially with respect to the axial direction.

5. A processing liquid supply device, A fine bubble generator according to claim 1 or claim 2, A supply unit that supplies a processing liquid containing fine bubbles generated by the fine bubble generator to the object to be processed, A processing liquid supply device equipped with the following features.

6. A substrate processing apparatus, Support part that supports the circuit board, A fine bubble generator according to claim 1 or claim 2, A supply unit that supplies a processing liquid containing fine bubbles generated by the fine bubble generator to the substrate supported by the support unit, A substrate processing apparatus comprising:

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