JP2011240218A - Fine bubble generating device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine bubble generating device and method which can efficiently generate fine bubbles in a liquid while saving a space and without temporarily storing the liquid containing the fine bubbles.SOLUTION: While circulating a treatment liquid L in a return circulation part 5, microbubbles are generated to increase the amount of the microbubbles contained in the treatment liquid L, and the treatment liquid L is sent from the downstream end 2B of liquid supply piping 2 to a treatment tank 100 through a flow control valve V1. As the flow rate of the treatment liquid L supplied to a bubble generation part 6 is controlled by two flow control valves V1, V2 and the flow rate of air supplied to the bubble generation part 6 is controlled by a needle valve V3, the treatment liquid L and air are supplied to the bubble generation part 6 at the optimum pressure and flow rate, whereby desired fine bubbles can be efficiently generated.

Description

  The present invention relates to a fine bubble generating apparatus and method for generating fine bubbles in a liquid.

  Microbubbles, for example, microbubbles having a diameter of 50 to 60 μm or less, shrink in a liquid such as water and disappear in water, that is, completely dissolve. It has been confirmed in recent studies that the pressure inside the bubbles is increased and the ions accumulated on the surface are further concentrated in the process of reducing the fine bubbles in water in this way (see Non-Patent Document 1). And it has been proposed in various fields to use these basic characteristics. For example, attempts have been made to purify water areas such as lakes and seas using fine bubbles such as microbubbles. Also, improve the cleaning efficiency by adding fine bubbles to the processing liquid for cleaning the surface of the semiconductor substrate or glass substrate, and decompose the chemical substances by adding fine bubbles to the cleaning liquid for cleaning foodstuffs etc. It has also been proposed. Furthermore, since it is possible to effectively remove a small amount of various harmful chemical substances, it has been proposed to improve the safety of drinking water by containing fine bubbles in the drinking water.

  For example, in Patent Document 1, a treatment liquid such as pure water containing microbubbles is stored in a treatment tank, and the substrate is immersed in the treatment liquid in the treatment tank to perform a treatment such as a cleaning treatment. In the apparatus described in Patent Document 1, the upper surface of the processing tank is open, and an outer tank is provided at the upper end of the outer surface. Then, the processing liquid overflowing into the outer tank is sucked into the gas-liquid mixing pump through the pipe. Further, a nitrogen gas supply source is connected to the pipe, and the nitrogen gas is introduced into the gas-liquid mixing pump together with the processing liquid. Nitrogen gas and the processing liquid are mixed by a gas-liquid mixing pump, and discharged to the processing tank through a swirl accelerator. In this way, microbubbles are contained in the processing liquid in the processing tank.

JP 2006-147617 A (for example, FIG. 1)

Masayoshi Takahashi, “Research Introduction 1. Introduction (Engineering Application of Fine Bubbles)” [online], updated April 26, 2010, Environmental Management Technology Research Institute, National Institute of Advanced Industrial Science and Technology, [April 2010 28 days search], Internet <http://staff.aist.go.jp/m.taka/Research.html>

  By the way, in the apparatus described in Patent Document 1, as described above, the processing liquid in the processing tank is circulated by the pump, and a microbubble generator is installed in the middle of the circulation path to generate microbubbles in the processing tank. I am letting. Thus, it is necessary to provide a treatment tank for storing the treatment liquid containing microbubbles (hereinafter referred to as “MB-containing liquid”). Further, in the apparatus described in Patent Document 1 described above, the substrate is processed in the processing tank, and the processing tank itself is a use point, but when the use point is separated from the microbubble generator, the MB It is necessary to provide a separate tank for storing the contained liquid. As described above, regardless of the positional relationship between the use point and the microbubble generator, it is necessary to provide a processing tank or tank for storing the MB-containing liquid in the conventional technique.

  Also, in order to increase the amount of microbubbles generated, it is generally performed to generate microbubbles in the processing liquid while circulating the processing liquid between the processing tank or tank and the microbubble generator. . In this case, in order to circulate the processing liquid, it is necessary to store an MB-containing liquid several times the amount of the processing liquid required for the substrate processing. It takes a long time to obtain an MB-containing liquid containing microbubbles. Thus, it was difficult to generate microbubbles efficiently.

  Furthermore, when the use point is away from the microbubble generator as described above, a piping system and a liquid feed pump for connecting the tank and the use point are additionally provided, and the MB-containing liquid in the tank is provided by the pump. Need to be pumped. In addition, when MB-containing liquid is used in existing equipment, it is necessary to secure a new space for installing the tank, branch off from existing piping that leads to a use point, and introduce microbubbles into the tank. After the inclusion, it is necessary to send the solution to the original piping to be merged, and an increase in size and complexity of the apparatus is inevitable.

  The present invention has been made in view of the above problems, and provides a fine bubble generating apparatus and method capable of efficiently generating fine bubbles in a liquid in a space-saving manner without temporarily storing a liquid containing fine bubbles. The purpose is to provide.

  In order to achieve the above object, the fine bubble generating device according to the present invention supplies a liquid via a liquid supply pipe for guiding the liquid in a predetermined liquid supply direction, and an upstream end of the liquid supply pipe provided in the liquid supply pipe. A pump that sucks and pumps in the liquid feeding direction and feeds it through the downstream end of the liquid feeding pipe, and a liquid circulation path that branches from the downstream end of the liquid feeding pipe and is connected to the upstream end of the liquid feeding pipe A return circulation part that constitutes the gas, a bubble generation part that generates gas by supplying gas to the liquid flowing in the circulation path, and a downstream side in the liquid feeding direction with respect to the branch position of the return circulation part from the liquid feeding pipe And a second adjustment unit for adjusting the flow rate of the liquid in the return circulation unit.

  Further, the fine bubble generating method according to the present invention is a fine bubble that generates fine bubbles in the liquid sucked from the upstream end portion of the liquid feed pipe by the pump provided in the liquid feed pipe and delivered to the downstream end portion of the liquid feed pipe. In order to achieve the above object, a part of the liquid flowing in the downstream end of the liquid feeding pipe is returned to the upstream end of the liquid feeding pipe through the circulation path, and the liquid flowing in the circulation path is gasified. To generate fine bubbles and contain them in the liquid.

  In the invention thus configured (microbubble generator and method), the liquid is sent out from the downstream end of the liquid supply pipe by the pump, but a part of the liquid flowing through the downstream end of the liquid supply pipe is part of the liquid supply pipe. Is returned to the upstream end. That is, a circulation path that diverges from the downstream end of the liquid supply pipe and is connected to the upstream end of the liquid supply pipe to circulate the liquid is formed. The first adjustment unit adjusts the liquid delivery amount, the second adjustment unit adjusts the liquid flow rate in the return circulation unit, and a part of the liquid flowing through the liquid supply piping returns to the liquid supply piping. It circulates between the parts. Further, gas is supplied to the circulating liquid in this way to generate fine bubbles, and the fine bubbles are efficiently contained in the liquid.

  Here, the return circulation part is connected between the first pipe branched from the downstream end of the liquid feeding pipe, the second pipe connected to the upstream end of the liquid feeding pipe, and the first pipe and the second pipe. You may comprise by the 3rd piping which connects, and the 4th piping which connects between 1st piping and 2nd piping. And the 2nd adjustment part is provided in the 3rd piping, and by adjusting the amount of liquid returned to the pump by this 2nd adjustment part, a fixed amount or more of liquid can always be returned to a pump, and a pump is good Can be operated. In addition, the flow rate adjustment by the first adjustment unit and the second adjustment unit adjusts the flow rate of the liquid flowing through the first piping, the fourth piping, and the second piping, so that an appropriate pressure and flow rate of the bubble generating unit can be obtained. The liquid can be supplied to generate desired fine bubbles.

  In addition, the second adjustment unit may be provided not only in the third pipe but also in the fourth pipe, whereby the pressure and flow rate of the liquid flowing into the bubble generation unit can be controlled with higher accuracy. The generated fine bubbles can be further optimized. Moreover, in order to increase the generation amount of fine bubbles, a plurality of fourth pipes may be provided, and a second adjustment unit and a bubble generation part may be provided in each fourth pipe. Thus, by providing a plurality of bubble generating parts in parallel with the first pipe and the second pipe, it is possible to efficiently generate fine bubbles in a short time with respect to the liquid.

  Further, by further providing a third adjustment unit that adjusts the gas supply flow rate to the bubble generation unit, the pressure and flow rate of the gas flowing into the bubble generation unit can be controlled with higher accuracy, and the bubble generation unit generates the gas flow rate. Fine bubbles can be further optimized. Here, when a plurality of fourth pipes are provided and a bubble generating part is provided in each fourth pipe, one third adjusting part may be provided for the plurality of bubble generating parts. Further, the bubble generation unit and the third adjustment unit may be provided in a “many-to-many” or “one-to-one” correspondence.

  Moreover, in order to generate a fine bubble in a bubble generation part, the gas-liquid shearing method which shears the gas supplied to a liquid and produces | generates a fine bubble can be used. For example, an aspirator can be used as the bubble generation unit using this gas-liquid shearing method.

  Furthermore, when the liquid flowing in the existing pipe is flowing, desired fine bubbles can be contained in the liquid in the existing pipe by connecting the upstream end and the downstream end of the liquid feeding pipe to the existing pipe. Note that if the pressure of the liquid in the liquid feeding pipe exceeds the pressure resistance of the existing pipe, the existing pipe may be damaged. In this case, the pressure reducing part is provided downstream in the liquid feeding direction with respect to the branch position of the return circulation part, and the pressure of the liquid sent from the downstream end of the liquid feeding pipe to the existing pipe is reduced to a pressure lower than that of the existing pipe. Is desirable.

  As described above, the liquid circulation path is formed with respect to the liquid supply pipe that guides the liquid by the pump, and the gas is supplied to the liquid flowing through the circulation path to generate the fine bubbles. The fine bubbles can be efficiently generated in the liquid without providing a tank for storing the liquid containing the liquid.

It is a figure which shows 1st Embodiment of the microbubble generator concerning this invention. It is a figure which shows 2nd Embodiment of the microbubble generator concerning this invention. It is a figure which shows 3rd Embodiment of the microbubble generator concerning this invention. FIG. 10 is a view showing a modification of the fine bubble generating device according to the third embodiment. It is a figure which shows 4th Embodiment of the microbubble generator concerning this invention. It is a figure which shows the example of improvement of the microbubble generator concerning 4th Embodiment. It is sectional drawing which shows an example of the aspirator used as a bubble generation part. It is sectional drawing which shows the other example of the aspirator used as a bubble generation part.

<First Embodiment>
FIG. 1 is a diagram showing a first embodiment of a microbubble generator according to the present invention. In this embodiment, the processing tank 100 is used as a use point, and the fine bubble generating apparatus 1A sucks the processing liquid L such as pure water from the processing tank 100 and contains the desired fine bubbles to obtain an MB-containing liquid. After that, it is an apparatus which sends out to the processing tank 100. The fine bubble generating apparatus 1A according to the first embodiment includes a liquid feeding pipe 2 that guides the processing liquid L in the processing tank 100 in a predetermined liquid feeding direction D. The upstream end 2 </ b> A of the liquid feeding pipe 2 is connected to the lower side of the processing tank 100, while the downstream end 2 </ b> B of the liquid feeding pipe 2 is connected to the upper side of the processing tank 100. A liquid feed pump 3 is provided at the center of the liquid feed pipe 2, that is, a water intake (not shown) of the pump 3 is connected to the treatment tank 100 via the upstream end 2 </ b> A of the liquid feed pipe 2. While being connected, the discharge port (not shown) of the pump 3 is connected to the processing tank 100 via the downstream end 2 </ b> B of the liquid feeding pipe 2. The pump 3 operates in accordance with an operation command from the control unit 4 that controls the entire apparatus, thereby sucking the processing liquid L from the processing tank 100 through the upstream end 2A of the liquid feeding pipe 2 and sending it. Pumped in the liquid direction D and sent to the treatment tank 100 via the downstream end 2B of the liquid feed pipe 2.

  Further, a return circulation unit 5 is attached to the liquid feeding pipe 2, and a circulation path is formed for returning a part of the processing liquid L fed from the discharge port of the pump 3 to the water intake port of the pump 3. More specifically, the return circulation unit 5 includes a first pipe 51 that branches from the downstream end 2B of the liquid feeding pipe 2, and a second pipe 52 that is connected to the upstream end 2A of the liquid feeding pipe 2. Yes. And the 3rd piping 53 is arrange | positioned in the vicinity of the pump 3, and it connects between the 1st piping 51 and the 2nd piping 52, and forms the 1st circulation path. Moreover, the front-end | tip part (right side edge part of FIG. 1) of the 1st piping 51 and the 2nd piping 52 is mutually connected by the 4th piping 54, and forms the 2nd circulation path. As described above, in the first embodiment, two circulation paths are formed, and the flow control valve V2 is disposed in the first circulation path. As described above, the flow control valve V2 is provided in the third pipe 53 so that the minimum flow rate of the processing liquid L returning to the pump 3 via the first circulation path can be adjusted. The flow control valve V2 is a variable flow valve, and adjusts the flow rate of the processing liquid L flowing through the third pipe 53 in accordance with a command from the control unit 4. As described above, in the first embodiment, the flow control valve V2 is controlled so that a predetermined amount or more of the processing liquid L is returned to the pump 3, and the pump 3 is always operated in a good state. Further, the flow rate of the processing liquid L flowing into the second circulation path is adjusted by the flow rate adjustment by the flow control valve V2. Thus, in the present embodiment, the flow control valve V2 functions as the “second adjusting unit” of the present invention.

  The bubble generating section 6 is disposed in the second circulation path, and air is supplied to the processing liquid L flowing in the fourth pipe 54 to generate microbubbles having a diameter of 50 to 60 μm or less in the processing liquid L. Let In the first embodiment, as will be described later, microbubbles are generated in the processing liquid L by the gas-liquid shearing method, and the air pressure-fed from an air supply source (not shown) is supplied to the bubble generating section via the needle valve V3. 6 to generate microbubbles, and the processing liquid L contains microbubbles to generate an MB-containing liquid. Thus, in the present embodiment, the pressure and flow rate of the air supplied to the bubble generating unit 6 are adjusted by the needle valve V3, and the needle valve V3 functions as the “third adjusting unit” of the present invention.

  The MB-containing liquid generated in this way is sent to the upstream end 2A of the liquid-feeding pipe 2 via the fourth pipe 54 and the second pipe 52 to increase the microbubble content in the processing liquid L. Then, the processing liquid L is sent out by the pump 3 through the downstream end 2B of the liquid feeding pipe 2. At the downstream end 2B of the liquid feeding pipe 2, a flow control valve V1 is provided on the downstream side (upper side in FIG. 1) in the liquid feeding direction D with respect to the branch position BP of the first pipe 51, and the downstream end 2B. It is possible to adjust the flow rate of the processing liquid L fed to the processing tank 100 via the. This flow control valve V1 is a variable flow valve, and adjusts the delivery amount of the processing liquid L in accordance with a command from the control unit 4. Further, the flow rate of the processing liquid L flowing into the return circulation unit 5 is controlled by adjusting the delivery amount by the flow control valve V1. Thus, in the present embodiment, the flow control valve V1 functions as the “first adjustment unit” of the present invention.

  In the fine bubble generating apparatus 1A configured as described above, when the pump 3 is operated in accordance with the operation command of the control unit 4 and each valve V1 to V3 is opened, the processing liquid L in the processing tank 100 is discharged by the pump 3. The air is sucked into the fine bubble generating device 1A and sent in the liquid feeding direction D through the liquid feeding pipe 2. Then, the processing liquid L sent out from the pump 3 flows into the first pipe 51 of the return circulation section 5 at the branch position BP at a rate corresponding to the degree of opening of the first flow control valve V1.

  Moreover, it flows into the 3rd piping 53 and the 4th piping 54 from the 1st piping 51 in the ratio according to the opening degree of the 2nd flow control valve V2, respectively. In the third pipe 53, the processing liquid L flows as it is along the first circulation path via the second flow control valve V2, and is supplied to the pump 3 via the second pipe 52 and the upstream end 2A of the liquid feed pipe 2. Returned. On the other hand, in the fourth pipe 54, the processing liquid L is sent to the bubble generating unit 6 at a flow rate corresponding to the degree of opening of the first flow control valve V <b> 1 and the second flow control valve V <b> 2. The bubble generating unit 6 is supplied with air whose flow rate and pressure are adjusted via the needle valve V3. As a result, the microbubbles are formed by being cut and pulverized by the processing liquid L, and the microbubbles are contained in the processing liquid L. The MB-containing liquid thus obtained flows along the second circulation path, and is returned to the pump 3 through the second pipe 52 and the upstream end 2A of the liquid feed pipe 2.

  As described above, in the first embodiment, the amount of microbubbles contained in the processing liquid L is increased by generating microbubbles (fine bubbles) while circulating the processing liquid L in the return circulation unit 5, and the flow control valve The liquid is fed from the downstream end 2B of the liquid feeding pipe 2 to the processing tank 100 via V1. Therefore, the MB-containing liquid can be efficiently obtained without providing a tank for storing the processing liquid L.

  Further, in the fine bubble generating device 1A according to the first embodiment, the minimum flow rate of the processing liquid L returned to the pump 3 is adjusted by the flow control valve V2 to always return a certain amount or more of the processing liquid L to the pump 3. Therefore, the pump 3 can be operated satisfactorily. In addition, the flow rate of the processing liquid L applied to the bubble generation unit 6 is adjusted by the two flow control valves V1 and V2, and the flow rate of the air supplied to the bubble generation unit 6 is adjusted by the needle valve V3. The processing liquid L and air having an optimal pressure and flow rate are supplied to the unit 6, and desired microbubbles (fine bubbles) can be efficiently generated.

Second Embodiment
FIG. 2 is a diagram showing a second embodiment of the microbubble generator according to the present invention. The microbubble generator 1B according to the second embodiment is greatly different from the first embodiment in that a flow control valve V4 is provided in the fourth pipe 54, and other configurations are the first embodiment. Is the same. That is, the processing liquid L flows into the bubble generating unit 6 through the fourth pipe 54, but the flow control valve V4 is disposed upstream of the bubble generating unit 6 (upper side in the figure) in the flow direction. . This flow control valve V4 is a variable flow valve, and adjusts the flow rate of the processing liquid L flowing into the bubble generating unit 6 in accordance with a command from the control unit 4. As described above, in the second embodiment, the flow control valve V4 is provided immediately before the processing liquid L flows into the bubble generating unit 6, so that the pressure and flow rate of the processing liquid L flowing into the bubble generating unit 6 can be further increased. The amount and size of the fine bubbles generated in the bubble generation unit 6 can be further optimized. As described above, in the present embodiment, the flow control valves V2 and V4 function as the “second adjusting unit” of the present invention, and this point is also applied to the microbubble generator according to the third embodiment described below. It is the same.

<Third Embodiment>
FIG. 3 is a view showing a third embodiment of the fine bubble generating apparatus according to the present invention. The microbubble generator 1C according to the third embodiment is greatly different from the first embodiment in that two fourth pipes 54 are provided, and the flow control valve V4 and the bubbles are provided in each fourth pipe 54. The point that the generating unit 6 is provided and the point that air is supplied to each bubble generating unit 6 via the needle valve V3, and other configurations are the same as those of the first embodiment.

  In the fine bubble generating device 1C according to the third embodiment, when the pump 3 is operated according to the operation command of the control unit 4 and the first flow control valve V1 is opened, the pump 3 is the same as in the first embodiment. A part of the processing liquid L sent out from the flow returns to the first pipe 51 of the return circulation section 5 at the branch position BP at a rate corresponding to the degree of opening of the first flow control valve V1.

  Further, by opening the flow control valves V2, V4, V4 simultaneously with the first flow control valve V1, the first pipe 51 to the third pipe 53 and the fourth pipe are proportioned according to the degree of opening of the flow control valves V2, V4. 54 and 54, respectively. In the third pipe 53, the processing liquid L flows as it is along the first circulation path via the second flow control valve V2, and is supplied to the pump 3 via the second pipe 52 and the upstream end 2A of the liquid feed pipe 2. Returned. On the other hand, in each 4th piping 54, the process liquid L is sent into the bubble generation part 6 with the flow volume according to the opening degree of the flow control valve V4. The bubble generating unit 6 is supplied with air whose flow rate is adjusted via the needle valve V3. As a result, as in the first embodiment, microbubbles (fine bubbles) are formed by the gas-liquid shearing method, and the processing liquid L contains microbubbles. The MB-containing liquid thus obtained flows along the second circulation path, and is returned to the pump 3 through the second pipe 52 and the upstream end 2A of the liquid feed pipe 2.

  As described above, in the third embodiment, as in the first embodiment, the MB-containing liquid generated by generating the microbubbles while circulating the processing liquid L in the return circulation unit 5 is passed through the flow control valve V1. Then, the liquid is fed from the downstream end 2 </ b> B of the liquid feeding pipe 2 to the treatment tank 100. Therefore, the same effect as the first embodiment, that is, the effect of efficiently obtaining the MB-containing liquid without providing a tank or the like for storing the processing liquid L can be obtained.

  Further, as described above, a plurality of bubble generating parts 6 are provided in parallel to the first pipe 51 and the second pipe 52, and microbubbles are simultaneously generated in each of the bubble generating parts 6. On the other hand, microbubbles can be generated efficiently in a short time. In the third embodiment, two bubble generating units 6 are arranged in parallel, but three or more fourth pipes 54 are inserted in parallel with respect to the first pipe 51 and the second pipe 52. The bubble generating unit 6 may be disposed in each fourth pipe 54. In addition, although one needle valve V3 is provided for the plurality of bubble generating units 6, the correspondence between the bubble generating unit 6 and the needle valve V3 is not limited to the above-mentioned “many-to-one”, The needle valve V <b> 3 may be provided for the bubble generating unit 6 in a “many-to-many” correspondence. Further, for example, as shown in FIG. 4, the same number of needle valves V3 as the number of bubble generating units 6 are prepared, and the air flow rate of each bubble generating unit 6 is adjusted via one needle valve V3. You may comprise so that it may supply. That is, the needle valve V3 may be provided for the bubble generating unit 6 in a “one-to-one” correspondence.

<Fourth embodiment>
The first to third embodiments described above use the treatment tank 100 as a use point, and the fine bubble generators 1A to 1C are arranged in the vicinity of the treatment tank 100, but the use point is fine. The present invention is also useful when away from the bubble generator. This is because, in such a case, piping is installed to supply the processing liquid to the use point, but the microbubble generator according to the present invention has a tankless structure as described above, so that the liquid feeding piping By connecting to the existing piping, a large amount of microbubbles can be efficiently contained in the processing liquid flowing in the existing piping. Hereinafter, the case where the fine bubble generating device 1A according to the first embodiment is installed in the existing pipe will be described with reference to FIG.

  FIG. 5 is a diagram showing a fourth embodiment of the microbubble generator according to the present invention. In this embodiment, a pipe 200 is already provided to supply the processing liquid L to a use point (not shown). The upstream end 2A and the downstream end 2B of the liquid feeding pipe 2 are communicated with the existing pipe 200. In the fourth embodiment, in the flow direction of the processing liquid L in the existing pipe 200 (the white arrow direction in the figure), the liquid supply pipe is positioned so that the upstream end 2A is located upstream of the downstream end 2B. 2 is connected to the existing pipe 200.

  In the fine bubble generating apparatus 1A, when the pump 3 is operated according to the operation command of the control unit 4 and each valve V1 to V3 is opened, the processing liquid that flows through the existing pipe 200 by the pump 3 as in the first embodiment. Part of L is sucked into the fine bubble generating device 1 </ b> A and circulated in the return circulation unit 5. During the circulation, the bubble generating unit 6 generates micro bubbles in the processing liquid L to generate the MB-containing liquid, and the MB-containing liquid is returned to the upstream end 2A of the liquid feeding pipe 2, and further the flow control valve It is sent out from the downstream end 2B of the liquid feed pipe 2 to the existing pipe 200 via V1. Therefore, microbubbles (fine bubbles) can be efficiently contained in the processing liquid L flowing in the existing pipe 200 without providing a tank or the like for storing the processing liquid L.

  As described above, in the fourth embodiment, the processing liquid L is sucked from the existing pipe 200 by the pump 3, the microbubbles are contained, and the liquid is sent to the existing pipe 200 via the liquid feeding pipe 2. The pressure of the processing liquid L (including the MB-containing liquid) in the inside exceeds the pressure resistance of the existing pipe 200, and the existing pipe 200 may be damaged. In such a case, a pressure reducing part is provided downstream of the branch position BP of the return circulation part 5 in the liquid feeding direction D, and the pressure of the processing liquid L sent out from the downstream end 2B of the liquid feeding pipe 2 to the existing pipe 200 It is desirable to reduce the pressure below the withstand pressure of the existing pipe 200. As this decompression portion, for example, as shown in FIG. 6, a decompression member 7 in which a pinching hole 71 is formed in the central portion and restricts the flow area of the processing liquid L can be used.

  FIG. 6 is a view showing an improved example of the microbubble generator according to the fourth embodiment. In this improved example, a pipe joint is provided at a part of the downstream end 2B of the liquid feeding pipe 2. In this pipe joint portion, the flange 21 is attached to the downstream end face of the upstream pipe 2Ba out of the two pipes 2Ba and 2Bb constituting the downstream end 2B, and the flange 21 is attached to the upstream end face of the downstream pipe 2Bb. Is attached. And the decompression member 7 of the same diameter as the flange 21 is inserted so that it may be pinched | interposed into those flanges 21 and 21. As shown in FIG. A disc-shaped thin plate 72 having substantially the same diameter as the inner diameters of the pipes 2Ba and 2Bb is attached to the central portion of the decompression member 7. The thin plate 72 is provided with a plurality of pinching holes 71 so as to partially regulate the processing liquid L flowing from the pipe 2Ba. Therefore, the pressure of the processing liquid L that has passed through the decompression member 7 is greatly reduced to be equal to or lower than the pressure resistance of the existing pipe 200. As a result, problems such as breakage of the existing pipe 200 can be effectively prevented.

<Others>
By the way, as the bubble generation part 6 employ | adopted by the said embodiment, what forms a microbubble by a gas-liquid shearing method, for example, the aspirator 6A comprised as shown in FIG. 7, can be used.

  FIG. 7 is a cross-sectional view showing an example of an aspirator used as a bubble generating unit. In the aspirator 6A, an inflow portion 61 that is connected to the upstream end portion of the fourth pipe 54 and into which the processing liquid L flows from the upstream side of the second circulation path (the left hand side in the figure), and the downstream end portion of the fourth pipe 54 Is connected to the outflow part 62 that flows out the processing liquid (MB-containing liquid) L toward the downstream side of the second circulation path (the right-hand side in the figure), and is coupled in a straight line. A suction part 63 for sucking is coupled at a substantially right angle. In this way, the inflow portion 61 and the outflow portion 62 constitute a part of the second circulation path, and the processing liquid L flows in the direction indicated by the one-dot chain line arrow in FIG.

  The inflow portion 61 has a steady portion 61A having a substantially constant cross-sectional area along the flow direction of the processing liquid, and a substantially constant slope toward the downstream side continuously downstream of the steady portion 61A. A reduced portion 61B whose cross-sectional area is reduced is formed. On the other hand, the outflow part 62 has an enlarged part 62A formed so that the cross-sectional area is enlarged with a substantially constant inclination toward the downstream side, and continuously along the flow direction of the processing liquid on the downstream side of the enlarged part 62A. Thus, a stationary part 62B having a substantially constant cross-sectional area is formed. In addition, a constriction part that reduces the cross-sectional area of the second circulation path is formed in the joint part between the inflow part 61 and the outflow part 62, and the suction part 63 communicates with the constriction part. Note that air is pumped from the air supply source to the suction portion 63 via the needle valve V3.

  The cross-sectional area of the suction part 63 is smaller than the cross-sectional areas of the steady part 61A of the inflow part 61 and the steady part 62B of the outflow part 62, and the water flowing in from the inflow part 61 passes through the throttle part. When flowing out to 62, the flow velocity becomes faster and negative pressure is generated on the throttle side, so that the so-called Venturi tube phenomenon causes air to be sucked from the suction part 63 to the throttle part as shown by the broken line arrow in FIG. Then, air is supplied to the processing liquid L flowing in the second circulation path. At this time, the air supplied to the throttle portion is sheared by the processing liquid L flowing at high speed to generate microbubbles (fine bubbles) and is contained in the processing liquid L. In this way, the MB-containing liquid is generated by the aspirator 6 </ b> A and returned to the upstream end 2 </ b> A of the liquid feeding pipe 2 through the fourth pipe 54 and the second pipe 52.

  By the way, in the aspirator (bubble generating part) 6 configured as shown in FIG. 7, the sectional area of the throttle part is fixed. By using the aspirator 6B configured as shown in FIG. Can be adjusted, fine bubbles can be generated under various conditions, and versatility can be improved.

  FIG. 8 is a cross-sectional view showing another example of an aspirator used as a bubble generating unit. The aspirator 6B is greatly different from the aspirator 6A in FIG. 7 in that an insertion portion 62C extends from the enlarged portion 62A of the outflow portion 62 to the upstream side (left hand side in the figure), and the inflow portion 61 In the state where the outflow part 62 is separated from each other and the reduction part 61B of the inflow part 61 enters the recess of the insertion part 62C, the inflow part 61 flows in the flow direction of the processing liquid L with respect to the outflow part 62 (the horizontal direction in the figure). ) Is relatively movable.

  In addition, the outer diameter of the front end of the reduced portion 61B is reduced at a substantially constant inclination toward the downstream side (the right-hand side in the figure), and the outer diameter at the most distal portion is the upstream where the enlarged portion 62A is formed. It is narrower than the diameter of the side opening, and the front end of the reduced portion 61B can advance and retreat with respect to the rear end opening of the enlarged portion 62A. An annular throttle portion is formed by separating the front end portion of the reduced portion 61B from the rear end opening of the enlarged portion 62A, and the sectional area of the throttle portion can be varied by adjusting the separated state. it can. Further, the suction part 63 is communicated with the throttle part via a space SP formed between the distal end part of the reducing part 61B and the concave part of the insertion part 62C. Therefore, by moving the inflow part 61 in the flow direction of the processing liquid L with respect to the outflow part 62 (left and right direction in the figure), the negative pressure state in the throttling part is changed, and the size of bubbles generated in the throttling part The amount can be controlled.

  The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described one without departing from the spirit of the present invention. For example, in the above embodiment, fine bubbles are generated by supplying air from an air supply source via the needle valve V3. For example, other gases such as nitrogen gas and ozone gas are generated according to the type of liquid. You may comprise so that it may supply to the part 6 and a fine bubble may be generated. That is, liquid and gas can be used in an appropriate combination according to the intended use of the fine bubble generator.

  Moreover, in the said embodiment, although the bubble generation part 6 uses what forms a microbubble by a gas-liquid shearing method, other methods, for example, melt | dissolve gas in large quantities under high pressure, and re-bubble by pressure reduction, are used. It is also possible to use what forms microbubbles by the so-called pressure-reducing method.

  In addition to the technique introduced in Non-Patent Document 1, the present invention provides a processing liquid such as a technique for generating a processing liquid for performing a predetermined substrate processing on a substrate such as a semiconductor wafer or a glass substrate for liquid crystal display. It can be applied to all technologies for generating fine bubbles.

DESCRIPTION OF SYMBOLS 1A-1C ... Fine bubble generator 2 ... Liquid feeding pipe 2A ... Upstream end part (of liquid feeding pipe) 2B ... Downstream end part (of liquid feeding pipe) 3 ... Liquid feeding pump 5 ... Return circulation part 6 ... Bubble generation Part 6A ... Aspirator 6B ... Aspirator 7 ... Pressure reducing member (pressure reducing part)
200 ... Existing piping BP ... Branching position D ... Liquid feeding direction L ... Treatment liquid V1 ... Flow control valve (1st adjustment part)
V2, V4 ... Flow control valve (second adjusting part)
V3 ... Needle valve (third adjusting part)

Claims (11)

A liquid supply pipe for guiding liquid in a predetermined liquid supply direction;
A pump that is provided in the liquid feeding pipe and sucks the liquid through the upstream end of the liquid feeding pipe and pumps the liquid in the liquid feeding direction and sends it out through the downstream end of the liquid feeding pipe;
A return circulation section that branches from the downstream end of the liquid feeding pipe and is connected to the upstream end of the liquid feeding pipe to constitute the circulation path of the liquid;
A bubble generating unit that generates gas by supplying gas to the liquid flowing in the circulation path;
A first adjustment unit that is provided on the downstream side in the liquid feeding direction with respect to the branch position of the return circulation unit from the liquid feeding pipe and adjusts the liquid delivery amount;
A fine bubble generating apparatus comprising: a second adjusting unit that adjusts a flow rate of the liquid in the return circulation unit. The return circulation section includes a first pipe branched from a downstream end of the liquid feeding pipe, a second pipe connected to the upstream end of the liquid feeding pipe, the first pipe, and the second pipe. A third pipe communicating between the first pipe and a fourth pipe communicating between the first pipe and the second pipe;
The fine bubble generating device according to claim 1, wherein the second adjustment unit is provided in the third pipe and the bubble generation unit is provided in the fourth pipe.   The fine bubble generating apparatus according to claim 2, wherein the second adjustment unit is further provided in the fourth pipe. The return circulation section includes a first pipe branched from a downstream end of the liquid feeding pipe, a second pipe connected to the upstream end of the liquid feeding pipe, the first pipe, and the second pipe. A third pipe that communicates with each other, and a plurality of fourth pipes that communicate between the first pipe and the second pipe,
2. The fine bubble generating device according to claim 1, wherein the second adjustment unit is provided in the third pipe, and the second adjustment unit and the bubble generation unit are provided in each of the plurality of fourth pipes. A plurality of third adjustment units provided in one-to-one correspondence with the plurality of bubble generating units;
The fine bubble generating device according to claim 4, wherein the plurality of third adjusting units adjust the supply flow rate of the gas to the corresponding bubble generating unit.   The fine bubble generator according to any one of claims 1 to 3, further comprising a third adjustment unit that adjusts a supply flow rate of the gas to the bubble generation unit.   The fine bubble generator according to any one of claims 1 to 6, wherein the bubble generation unit generates the fine bubbles by shearing the gas supplied to the liquid.   The fine bubble generating apparatus according to claim 7, wherein the bubble generating unit is an aspirator. The microbubble generator according to any one of claims 1 to 8, wherein the microbubbles are generated in the liquid flowing in an existing pipe,
A fine bubble generating apparatus in which an upstream end portion and a downstream end portion of the liquid supply pipe can be connected to the existing pipe.   The pressure of the liquid that is provided at the downstream end of the liquid supply pipe on the downstream side in the liquid supply direction with respect to the branch position of the return circulation section and is sent from the downstream end of the liquid supply pipe to the existing pipe The fine bubble generating apparatus according to claim 9, further comprising a pressure reducing unit that reduces the pressure to a level equal to or lower than a pressure resistance of the existing pipe. A fine bubble generating method for generating fine bubbles in a liquid sucked from an upstream end of the liquid supply pipe by a pump provided in the liquid supply pipe and sent to a downstream end of the liquid supply pipe,
Generates fine bubbles by supplying gas to the liquid flowing in the circulation path while returning a part of the liquid flowing in the downstream end of the liquid supply pipe to the upstream end of the liquid supply pipe via the circulation path. A method for generating fine bubbles, characterized in that the liquid is contained in the liquid.

Images