Printed by Jouve, 75001 PARIS (FR)

(19)E

P3

009

184

A1

(Cont. next page)

TEPZZ¥ZZ9_84A_T(11) EP 3 009 184 A1

(12) EUROPEAN PATENT APPLICATIONpublished in accordance with Art. 153(4) EPC

(43) Date of publication: 20.04.2016 Bulletin 2016/16

(21) Application number: 13886736.1

(22) Date of filing: 13.06.2013

(51) Int Cl.:B01F 3/04 (2006.01) A61L 9/18 (2006.01)

B01F 5/02 (2006.01) B01F 5/20 (2006.01)

B08B 3/10 (2006.01) C02F 1/50 (2006.01)

C02F 1/72 (2006.01) C02F 1/76 (2006.01)

C02F 1/78 (2006.01)

(86) International application number: PCT/JP2013/066902

(87) International publication number: WO 2014/199525 (18.12.2014 Gazette 2014/51)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TRDesignated Extension States: BA ME

(71) Applicant: Sigma-Technology Inc.Hitachinaka-shi, Ibaraki 312-0011 (JP)

(72) Inventors: • TACHIBANA, Yoshiaki

Hitachinaka-shiIbaraki 312-0011 (JP)

• TACHIBANA, KousukeHitachinaka-shiIbaraki 312-0011 (JP)

• HARADA, KaoruHitachinaka-shiIbaraki 312-0011 (JP)

• SASAJIMA, SouzouHitachinaka-shiIbaraki 312-0011 (JP)

• TAMAHASHI, KunihiroHitachinaka-shiIbaraki 312-0011 (JP)

• HONMA, KyokoHitachinaka-shiIbaraki 312-0011 (JP)

• MATUMOTO, YuukiHitachinaka-shiIbaraki 312-0011 (JP)

(74) Representative: Moore, Graeme Patrick et alMewburn Ellis LLP City Tower 40 Basinghall StreetLondon EC2V 5DE (GB)

(54) MICRO AND NANO BUBBLE GENERATING METHOD, GENERATING NOZZLE, AND GENERATING DEVICE

(57) A new method for generating micro-nano bub-bles that uses water hammering, a bubble generatingnozzle, and an apparatus for generating micro-nano bub-bles are provided to construct a system. The system isfor generating micro-nano bubbles in a large amount us-ing only pure water, which does not include any nucleat-ing agents, and for performing not only a clean washingand sterilization but also generation of uncontaminatedmicro-nano bubbles. The method defined in the presentinvention uses water hammering power produced by amutual collision of jets of dissolved-gas-including solu-tion squirted from two or more spouts. The bubble gen-erating nozzle by the present invention has a configura-tion, comprising: a hollow cylinder having two or more

small through-holes arrayed in the circumferential direc-tion thereof and a micro-nano bubble discharge port pro-vided on the both ends of the hollow cylinder, whereinthe small through-holes are arranged so that all of theirextension lines passing through respective center of thecross-section of each of the small through-holes intersecteach other in the inside of the hollow of the cylinder. Theapparatus for generating bubble by the present inventionhas such bubble generating nozzle and has a configura-tion that enables generation of micro-nano bubbles in alarge amount.

2

EP 3 009 184 A1

EP 3 009 184 A1

3

5

10

15

20

25

30

35

40

45

50

55

Description

{TECHNICAL FIELD}

[0001] The present invention relates to a method for,a bubble generating nozzle for, and an apparatus for gen-erating micro-nano bubbles, wherein the method, thenozzle, and the apparatus use water hammering.

{BACKGROUND OF THE INVENTION}

[0002] Washing or sterilizing by micro-nano bubbles isa method that uses only water, air, and additives of atrace quantity, offering a reduced environmental load.Due to this, such method have attracted attention as analternative to a conventional method for washing or ster-ilizing that uses materials like detergents and chemicals.In addition, because of such method being highly safe,application as a sterilization method for vegetables andfoods has been studied. Conventional methods for gen-erating micro-nano bubbles have been known in threefashions: the gas-liquid two-phase swirl flow method, theventuri tube method, and the pressure dissolution meth-od. (For example, refer to Patent Literatures 1 and 2 forthe gas-liquid two-phase swirl flow method and the pres-sure dissolution method.)[0003] Such conventional methods are however notsatisfactory because the number of micro-nano bubblesgenerated by each of such methods is still not largeenough. Although each of such conventional three meth-ods can easily produce micro-bubble water, nucleatingagent like base and magnesium must be added to themicro-nano water for generating a sufficient number ofmicro-nano bubbles. Addition of a nucleating agent hasbeen a major obstacle in expansion of application towashing and sterilization of such as semiconductor de-vices and food. At present however, it is very difficult togenerate a large amount of micro-nano bubbles usingpure water.[0004] Pumps of various types are employable as thedriving pump in an apparatus that generates bubbles us-ing water, air, and additives of a trace quantity. However,washing and sterilization of semiconductor devices andfood require that all the pertinent apparatus componentsincluding the driving pump should operate without caus-ing metal contamination. For example, when devicessuch as semiconductor wafers are to be washed withoutmetal contaminations, all the wetted parts of pumps tobe used in an apparatus for generating micro-nano bub-bles should be made of those which do not generate anymetal ions; and further, such pumps must operate stablyat a discharge pressure of 0.3 to 0.6 MPa.[0005] In consideration for these, the inventors of thepresent invention have proposed an apparatus that em-ploys a compressed-air driven bellows-cylinder pump asa pump that feeds liquid without using rotating move-ments (Patent Literatures 3 and 4). All the wetted partsof the proposed pump are made of fluorine resin to avoid

the feared metal contamination that will occur in a rotatingtype pump. To achieve the goal of performing a cleanwashing without the influence of contamination, technicaldevelopment is desired on application of plastic by useof such as fluorine resin to all the related constituent unitsfor generating micro-bubbles, including not only pumpsbut also nozzles.[0006]

{Patent Literature 1}Laid-open patent application TOKKAI 2009-274045{Patent Literature 2}Laid-open patent application TOKKAI 2008-264771{Patent Literature 3}Patent No. 4547451{Patent Literature 4}Patent No. 4924907

{SUMMARY OF THE INVENTION}

[0007] In conventional technologies, it is extremely dif-ficult to generate a large amount of micro-nano bubblesonly with pure water but without using nucleating agent.Granted that addition of a nucleating agent is intended,the agent is required to be used in a significantly reducedamount. In addition, if micro-nano bubbles can be gen-erated in an amount considerably larger than a quantitythat conventional technologies will generate, great im-provement in washing and sterilization can be expectedand, further, the broadening of application of such tech-nique to various usages becomes practicable. Thus, amethod for generating micro-nano bubbles by a newtechnique instead of prior arts and an apparatus for gen-erating micro-nano bubbles capable of actualizing suchnew technique have been strongly desired.[0008] In the technical field to which the present inven-tion relates, constructing a system capable of generatingmicro-nano bubbles without metal contamination is stillbeing sought as in the past. As stated above, a prospectthat this problem can be solved by employing a com-pressed-air driven bellows-cylinder pump, in which allthe wetted parts thereof are made of fluorine resin, isobtained. Moreover, if micro-nano bubbles can be gen-erated in an amount considerably larger than a conven-tional quantity using a micro-nano bubble generating ap-paratus that employs the pump of such configuration, itis expected that such bubble-generating method will bea useful washing method as a response to a demand bytechnical movements toward the fining of wiring in man-ufacturing semiconductor devices. At present however,a high performance apparatus of metal-free material thatcan generate increased amount of bubbles has not beenavailable.[0009] Therefore, it is strongly desired to establish anew method for generating micro-nano bubbles and todevelop a high-performance apparatus for generatingmicro-nano bubbles, by general optimization of structureand shapes of constituents including pumps and other

1 2

EP 3 009 184 A1

4

5

10

15

20

25

30

35

40

45

50

55

constituting parts such as a bubble generating nozzle, agas-liquid mixing vessel, and a liquid-feeding device. Ul-timately, it is necessary to construct a system capable ofgenerating micro-nano bubbles without metal contami-nation.[0010] In view of the background described above, anobject of the present invention is to provide an apparatusfor generating micro-nano bubbles to construct a systemthat performs clean washing and sterilizing with largeamount of micro-nano bubbles generated using pure wa-ter only and can generate micro-nano bubbles withoutmetal contamination. The apparatus intended to be pro-vided, including a bubble generating nozzle and an auto-regulating gas-liquid mixing vessel is to operate on a newmethod, which is different from conventional arts, for gen-erating micro-nano bubbles using water hammering.[0011] The basic idea for solving the problem de-scribed above is use of violent water hammering to gen-erate a large amount of micro-nano bubbles that containsdissolved gas, wherein the water hammering occurs oncollision of water, a non-compressive substance. To ac-tualize this, the inventors of the present invention hasbeen led to the present art through, in the method forgenerating micro-nano bubbles and the apparatus there-for, optimizing the structure and the shape of the bubblegenerating nozzle so that the water hammering powerwill work to its utmost extent and constructing an appa-ratus for generating micro-nano bubbles having a con-figuration that accelerates generating large amount ofmicro-nano bubbles.[0012] Thus, the configuration of the present inventionis as follows:

(1) The present invention provides a method for gen-erating micro-nano bubbles, wherein the method us-es water hammering power that is produced by mu-tual collision of jets of a solution, which includes dis-solved gas, squirted out from each of two or morespouts.(2) The present invention provides the method forgenerating micro-nano bubbles as described in theparagraph (1), wherein the method uses water ham-mering power to generate micro-nano bubbles,wherein micro-nano bubbles are generated by a mu-tual collision of jets of a dissolved liquid of a gas-liquid mixture state; the collision of jets is createdinside a cylinder that has two or more small through-holes; and the jets of the dissolved liquid are pro-duced by injecting the liquid from the outside of thecylinder via the small through-holes in the cylinderat a pressure higher than the atmospheric pressure.(3) The present invention provides the method forgenerating micro-nano bubbles as described in theparagraph (2), comprising the processes of:

a sucking process that sucks gas and liquid;a pressurization process that pressurizes gasand liquid;

a dissolved gas enriching process, wherein thepressurized gas-including liquid is mixed withanother new gas;a dissolved gas miniaturization process thatgenerates micro-nano bubbles,wherein a dissolved liquid of a gas-liquid mixturestate prepared at the dissolved gas enrichingprocess is injected from the outside of the cyl-inder having two or more small through-holes,via such small through-holes at a pressure high-er than the atmospheric pressure to produce jetsof the liquid, and the jets are collided mutuallyinside the cylinder.

(4) The present invention provides the method forgenerating micro-nano bubbles as described in anyof the paragraphs (1) to (3), wherein the pressure ofbeing more than the atmospheric pressure at thetime of squirting is 0.2 to 0.6 MPa, and the diameterof the small through-holes at the part leading to thehollow of the cylinder is 0.1 to 6.0 mm.(5) The present invention provides the method forgenerating micro-nano bubbles as described in anyof the paragraphs (1) to (4), wherein the dissolvedliquid is an aqueous solution that includes at leastone of substance selected from the group consistingof ozone, oxygen, hydrogen peroxide, chloric acid,perchloric acid, and potassium permanganate.(6) The present invention provides the method forgenerating micro-nano bubbles as described in anyof the paragraphs (1) to (4), wherein the dissolvedliquid is an aqueous solution that includes a sub-stance selected from the group consisting of carbondioxide, hydrogen gas, and nitrogen gas.(7) The present invention provides a bubble gener-ating nozzle for use in the generating of micro-nanobubbles using water hammering power, comprising:

a hollow cylinder having two or more smallthrough-holes arrayed in the circumferential di-rection thereof anda micro-nano bubble discharge port provided onat least one end of the hollow cylinder,wherein the small through-holes are arrangedso that all of their extension lines passingthrough respective center of the cross-sectionof each of the small through-holes intersect eachother in the inside of the hollow of the cylinder.

(8) The present invention provides the bubble gen-erating nozzle for generating micro-nano bubbles asdescribed in the paragraph (7), wherein the nozzlehas two or more numbers of hollow cylinders.(9) The present invention provides the bubble gen-erating nozzle for generating micro-nano bubbles asdescribed in the paragraph (8), wherein the hollowcylinders of two or more numbers are arranged inparallel to or perpendicular to the direction of the

3 4

EP 3 009 184 A1

5

5

10

15

20

25

30

35

40

45

50

55

inflow or the discharge of the flow of the dissolvedliquid.(10) The present invention provides the bubble gen-erating nozzle for generating micro-nano bubbles asdescribed in any of the paragraphs (7) to (9), whereinthe hollow cylinder has, in its longitudinal direction,a multi-row of two or more rows of small through-holes, and each of such rows consists of two or moresmall through-holes.(11) The present invention provides the bubble gen-erating nozzle for generating micro-nano bubbles asdescribed in any of the paragraphs (7) to (10), where-in the diameter of the small through-hole at the partthat leads to the hollow of the hollow cylinder is 0.1to 6.0 mm.(12) The present invention provides the bubble gen-erating nozzle for generating micro-nano bubbles asdescribed in any of the paragraphs (7) to (11), where-in the diameter of the micro-nano bubble dischargeport provided on at least one end of the hollow cyl-inder is equal to or larger than the diameter of a partof the hollow cylinder, wherein such part is such apart where the small through-holes are arranged ina circumferential direction.(13) The present invention provides an apparatusfor generating micro-nano bubbles, comprising:

a means for sucking each of gas and liquid;a means for pressurizing the gas and the liquidin a lump and transferring them;a gas-liquid mixing vessel for enriching the dis-solved gas by mixing the transferred liquid,which includes the gas, with another new gas;anda means for generating micro-nano bubbles inthe gas-liquid mixing vessel using the dissolvedliquid of the gas-liquid mixing state, wherein themeans has the bubble generating nozzle forgenerating micro-nano bubbles as described inany of paragraphs (7) to (12).

(14) The present invention provides the apparatusfor generating micro-nano bubbles as described inthe paragraph (13), wherein, in the means for gen-erating micro-nano bubbles, the dissolved liquid issquirted at a pressure of 0.2 to 0.6 MPa through thesmall through-hole of the bubble generating nozzle.(15)The present invention provides the apparatus forgenerating micro-nano bubbles as described in theparagraphs (13) or (14), wherein the gas-liquid mix-ing vessel has the bubble generating nozzle for gen-erating micro-nano bubbles, and the liquid that in-cludes the gas transferred by the means for pressu-rizing and transferring is discharged into the gas-liquid mixing vessel by the bubble generating nozzle.(16) The present invention provides the apparatusfor generating micro-nano bubbles as described inany of the paragraphs (13) to (15), wherein the gas-

liquid mixing vessel has a float valve inside or outsidethe vessel to maintain the volume of the gas and theliquid and the internal pressure inside the vessel al-ways within a prescribed range by discharging ex-cess gas from the vessel.(17) The present invention provides the apparatusfor generating micro-nano bubbles as described inany of the paragraphs (13) to (16), wherein a pumpor piping, or both, through which the gas-liquid mix-ture liquid flows, is made of plastic.(18) The present invention provides the apparatusfor generating micro-nano bubbles as described inthe paragraph (17), wherein a pump or piping, orboth, through which the gas-liquid mixture liquidflows, is made of fluorine resin.(19) The present invention provides the apparatusfor generating micro-nano bubbles as described inany of the paragraphs (13) to (18), wherein themeans for pressurizing and transferring the liquidthat includes the gas is an apparatus that uses acompressed-air driven or an electric motor drivenbellows cylinder pump.(20)The present invention provides the apparatus forgenerating micro-nano bubbles as described in anyof the paragraphs (13) to (19), wherein the dissolvedliquid is an aqueous solution that includes at leastone of substance selected from the group consistingof ozone, oxygen, hydrogen peroxide, chloric acid,perchloric acid, and potassium permanganate.(21)The present invention provides the apparatus forgenerating micro-nano bubbles as described in anyof the paragraphs (13) to (19), wherein the dissolvedliquid is an aqueous solution that includes a sub-stance selected from the group consisting of carbondioxide, hydrogen gas, and nitrogen gas.

[0013] The method for generating micro-nano bubblesby the present invention generates micro-nano bubblesusing the water hammering power. Therefore, the meth-od is able to generate micro-nano bubbles in a largeamount using pure water only without use of substanceswhich are not necessarily needed such as nucleatingagents. Accordingly, the method can realize a cleanwashing and sterilization. Since this water hammeringpower is maximized by the use of a bubble-generatingnozzle having an optimized structure and shape, the useof such optimized nozzle makes it possible to performcontinuous and stable generation of bubbles in an effi-cient manner. Thereby, the amount of generation ofsmall-size bubbles, not only of the size of micrometerorder but also of nanometer order, can be increased to-gether. This feature enhances the capability and functionin the washing and sterilizing more than those in conven-tional technique.[0014] The apparatus for generating micro-nano bub-bles by the present invention has a bubble generatingnozzle and equipment configuration that permits the gen-erating of bubbles in a large amount stably; therefore,

5 6

EP 3 009 184 A1

6

5

10

15

20

25

30

35

40

45

50

55

the apparatus is usable in a set of equipment for cleanwashing and sterilizing with pure water.[0015] On the other hand in the gas-liquid mixing ves-sel that dissolves gas in liquid, transferring gas and liquidin a lump by a pump may sometimes prevent generatinguniform micro-nano bubbles. This is because that, if thereoccurs a phenomenon in which the volume of the gasincreases, causing the inside of the gas-liquid mixturevessel to become full of gas and the volume of liquid inthe vessel to be lessened, the gas not dissolved in liquidis fed to the bubble generating nozzle in an as-gas-statecausing an unstable generation of micro-nano bubbles.This problem is solvable by discharging excess gas fromthe gas-liquid mixing vessel through a float valve provid-ed inside or outside the vessel. With this float valve, thevolume of the gas and the liquid are maintained alwayswithin a prescribed range and thereby the amount of gen-eration of the micro-nano bubbles becomes constant.[0016] Further, for a clean washing that is incompatiblewith metal ion which a wetted part generates, configuringa pump or piping, or both, in a washing apparatus withplastic or preferably with fluorine resin makes the appa-ratus become to have high reliability and clean feature.[0017] The method and the apparatus by the presentinvention contribute to constructing a micro-nano bubblegenerating system that generates bubbles without metalcontaminations. For example, application of the presentinvention to washing such as semiconductor wafers sim-plifies such washing process compared to conventionalprocesses that perform complicated washing using suchas drug solutions. Further, the invention is cable of re-ducing environmental load because the invented methoddoes not need use of material such as drug solutions.Moreover, the use of the invention for sterilization of foodssuch as vegetables makes it possible to perform reliableand safe sterilization.

{BRIEF DESCRIPTION OF THE DRAWINGS}

[0018]

FIG. 1 is a front view of a micro-nano bubble gener-ation system to which the present invention is ap-plied.FIG. 2 is a perspective view of the micro-nano bubblegeneration system to which the present invention isapplied.FIG. 3 is a cross sectional view of a micro-nano bub-ble generating nozzle.FIG. 4 is a front view of the micro-nano bubble gen-erating nozzle.FIG. 5 is a side view of the micro-nano bubble gen-erating nozzle.FIG. 6 illustrates a high-speed jet liquid squirting noz-zle part.FIG. 7 is an enlarged partial cross sectional view ofthe high-speed jet liquid squirting nozzle part.FIG. 8 is a cross sectional view of a nozzle that gen-

erates micro-nano bubbles.FIG. 9 is a cross sectional detail view of a liquid-collision nozzle with which micro-nano bubbles aregenerated.FIG. 10 is a front view, a cross sectional view, anda three-dimensional view of the liquid-collision noz-zle.FIG. 11 illustrates a liquid-collision nozzle havingmulti-row of groups of liquid squirting holes.FIG. 12 is a cross sectional view of a gas-liquid mix-ing vessel.FIG. 13 is a detail view of structure of a high-efficien-cy gas-liquid injection pipe for mixing gas and liquidin the gas-liquid mixing vessel.FIG. 14 is a cross sectional view of a float part to beequipped on the gas-liquid mixing vessel.FIG. 15 is a cross sectional view of the gas-liquidmixing vessel having a bubble generating nozzle bythe present invention.FIG. 16 is a cross sectional view of a multi-row nozzleof another configuration that generates micro-nanobubbles.FIGS. 17A to 17E are a perspective view and a crosssectional view of the structures of the liquid-collisionnozzles by the present invention.FIGS. 18A and 18B are a perspective view and across sectional view of the structures and shapes ofthe nozzle cylinders by the present invention.FIG. 19 is an illustration that shows the relationshipbetween the flow rate of the jet squirted from thesmall through-hole of the liquid-collision nozzle andthe flow rate of the discharge from the discharge port.FIG. 20 is a graph that shows schematically the re-lationship between the diameter of the small through-hole of the liquid-collision nozzle and the number ofbubbles per unit volume.FIG. 21 is a graph that shows the relationship be-tween the diameter of the small through-hole of theliquid-collision nozzle and the flow rate Q at the noz-zle.FIG. 22 is a graph that shows the amount of bubblesgenerated by the method for generating micro-nanobubbles by the present invention and the particle di-ameter of the generated bubbles.FIG. 23 is a graph that shows the amount of bubblesgenerated by a conventional gas-liquid two-phaseswirl flow method and the particle diameter of thegenerated bubbles.

{DETAILED DESCRIPTION OF THE PREFERED EM-BODIMENTS}

[0019] The following describes the best mode for car-rying out the present invention, referring to drawings.[0020] FIG. 1 is a front view of the micro-nano bubblegenerating system to which the present invention is ap-plied and FIG. 2 is a perspective view of the same. Eachof the reference numerals therein denotes;

7 8

EP 3 009 184 A1

7

5

10

15

20

25

30

35

40

45

50

55

15: a bellows cylinder pump,13: a pump controller,14: a gas-liquid mixing vessel,12: a pressure sensor,11: a micro-nano bubble generating nozzle attachmentpart,17: a liquid sucking pipe,16: a gas sucking port, and18: a gas sucking regulating valve.[0021] These constituents are arranged as illustratedin a perspective view FIG. 2. The bellows cylinder pump15, wetted parts of which are made of fluorine resin, sucksgas and liquid into the pump in a mixture state throughthe liquid sucking pipe 17 and the gas sucking regulatingvalve 18, with the volume of the gas regulated. Thesucked liquid and gas mixture is agitated and com-pressed inside the bellows to dissolve the gas in the liq-uid. In the present invention, if the bellows cylinder pump15 has a metal free structure, such configuration isenough. Any plastic other than fluorine resin can also beuseable. Usable plastic includes at least one of plasticsselected from the group consisting of, for example: gen-eral purpose plastics such as polyethylene, polypropyl-ene, and polyethylene terephthalate; engineering plas-tics such as polyacetar, polyamide, polycarbonate, anddenaturing polyphenylene ether; and super engineeringplastics such as polyether sulfone, polyphenylenesulfide, polyether ether ketone, and liquid crystal poly-mer. When use of plastic is intended, applying abovestated various plastics including fluorine resin to the wet-ted part, not only to the pump only, will provide an appa-ratus for generating micro-nano bubbles having a highreliability and cleanliness. In addition to the above, whenwashing or sterilizing in a strict metal free condition is notrequired, metals and ceramics may be used as well asthose plastics mentioned above.[0022] Next, the gas and the liquid are agitated by thepump 15 and are force-fed to the gas-liquid mixing vessel14. The pump 15 used is mainly a bellows cylinder pumpof compressed-air driven type but an electric motor driventype may be used. The gas and the liquid in the gas-liquidmixing vessel 14 are under the pressure generated bythe pump 15; therefore, the gas is easily dissolved. Thepressure that force-feeds the gas and the liquid from thepump 15 is watched by the pressure sensor 12. Increas-ing the quantity of the dissolved gas with this manner,the preparations are made for increasing the amount ofgeneration of the micro-nano bubbles. In the micro-nanobubble generating system by the present invention, it isa practical manner to use a bellows cylinder pump as thepump 15. Depending on the use purpose however, con-ventional known pumps are applicable. The applicablepumps include a reciprocating pump such as a pistonpump, a plunger pump, or a diaphragm pump; or a rotarypump such as a gear pump, an eccentric pump, or ascrew pump.[0023] The liquid entered under force-feeding the gas-liquid mixing vessel 14 mixes with gas to dissolve the

gas thereinto and then is transferred to the micro-nanobubble generating nozzle attachment part 11. The micro-nano bubble generating nozzle attachment part 11 is apart to which a nozzle connects, wherein the nozzle gen-erates, from the gas-dissolved liquid, micro-nano bub-bles in a large amount having a diameter of 60 mm orsmaller, preferably to be 15 mm or smaller.[0024] At that time, the pressure sensor 12 senses var-iation of the liquid pressure at the section between themicro-nano bubble generating nozzle attachment part 11and the gas-liquid mixing vessel 14 to watch the dissolv-ing conditions of the gas-liquid. By this, a constant pres-sure condition needed for stable generation of micro-na-no bubbles is actualized.[0025] The process to be performed by the apparatusfor generating micro-nano bubbles to which the presentinvention is applied is as follows. Treatments that the gassucking port 16, the liquid sucking pipe 17, and the gassucking regulating valve 18 perform are the gas- andliquid-sucking process. The pressure is regulated by thepressure sensor 12. Next, the gas-including liquid is pres-surized using the bellows cylinder pump 15; this treat-ment is the gas-liquid pressurization process. Followingthis process, the pressurized gas-including liquid ismixed with another new gas using the pump controller13 and the gas-liquid mixing vessel 14; this treatment isthe dissolved gas enriching process. After this, the bub-ble generating nozzle by the present invention, whichnozzle will be mentioned later, is connected to the micro-nano bubble generating nozzle attachment part 11 togenerate micro-nano bubbles. This process is referredto as the dissolved liquid miniaturization process, inwhich the micro-nano bubbles are generated by injectingthe dissolved liquid from the outside of a cylinder, whichhas two or more small through-holes, via such smallthrough-holes at a pressure higher than the atmosphericpressure to produce jets of the liquid, and the jets arecollided mutually at one point inside the cylinder.[0026] Next, explanation follows to describe a methodfor generating micro-nano bubbles in a large amount fromthe dissolved liquid that is in a gas-dissolved state. FIG.3 is a cross sectional view of the micro-nano bubble gen-erating nozzle including an attachment part. In the figure,reference numerals 1 and 2 are the outer cases of thenozzle, which are disposed facing each other and fas-tened together using a bolt 8 and a nut 9, wherein thedissolved liquid force-fed by the pump is divided into twostreams and each of the streams is separately introducedinto the outer cases 1 and 2 as arrows show. In each ofthe outer cases so disposed, a recess is provided to ac-commodate the high-speed liquid jet squirting nozzleparts 3 and 4. The size of the nozzle hole determines theflow rate and the flow velocity of the liquid discharge.[0027] FIG. 4 illustrates the nozzle in the fabricatedstate, in which the bolt 8 is tightening-fastened by the nut9. The water that produced micro-nano bubble is dis-charged in the radial direction indicated by arrows. FIG.5 is a side view of the micro-nano bubble generating noz-

9 10

EP 3 009 184 A1

8

5

10

15

20

25

30

35

40

45

50

55

zle by high-speed liquid jet squirting, in which the micro-nano bubble water is discharged in the circumferentialdirection.[0028] The following explains how to generate the mi-cro-nano bubbles using the water stream squirted fromthe high-speed liquid jet squirting nozzle. The gas-dis-solved liquid is discharged from the high-speed liquid jetsquirting nozzle at the discharge pressure of 0.2 MPa to0.6 MPa given by the high-pressure pump 15. The dis-charged liquid rapidly releases its pressure and collidesviolently each other producing a water hammering power.The explosive water hammering smashes the gas-dis-solve liquid and makes the liquid to be in a state that alarge amount of micro-nano bubbles is involved therein.It should be noted that, depending on the method of re-lease, there is a case where the amount of generation ofmicro-nano bubbles becomes reduced. However, the mi-cro-nano bubbles can be generated in a large amountwith the method and the apparatus by the present inven-tion.[0029] FIG. 6 is a cross sectional view taken along theline B-B and an outline view of the high-speed liquid jetsquirting nozzle parts 3 and 4 that generate micro-nanobubbles. The high-speed liquid jet squirting nozzle parts3 and 4 are, as illustrated in the cross sectional view,centered relying on the centering pin 5, which definesthe center, and positioned guided by the positioning pins6 and 7, and then fixed. The high-speed liquid jet squirtingnozzle parts 3 and 4 generate the micro-nano bubbles.[0030] FIG. 7 is an enlarged cross sectional view ofthe high-speed liquid jet squirting nozzle parts 3 and 4illustrated in FIG. 6. Since these parts 3 and 4 have thesame shape and disposed symmetrically, the followingexplains using reference numerals 3 and 4 for simplicity.To feed the gas-dissolved liquid to 3 and 4 in high-speedjets, the liquid stream is narrowed at small-hole flow pas-sages 3a and 4a. Thereby the jet stream squirts from theend of small-hole flow passages 3a and 4a that narrowthe liquid stream. Nozzle parts 3b and 4b are arrangedso that the jets squirted from each of the high-speed liquidjet squirting nozzle parts 3 and 4 collide, producing micro-nano bubbles from the collided gas-dissolved liquid. Themicro-nano bubbles that involve gas inside diffuse in thecircumferential direction indicated by arrows.[0031] The reason of feeding the liquid at a high-pres-sure is to increase the speed of the liquid in squirting fromthe small-hole. This means that making the liquid collisionhigh-speed increases the impact energy and that a largeamount of micro-nano bubbles of more minute size canbe generated thereby.[0032] Assume that F is the power of collision. Alsoassume that the density of a liquid is p, the size of a small-hole S, and the velocity of a liquid V. Then, the relation-ship of F = ρSV2 holds. For the optimal value of F, theoptimum design that considers the relation between thesize of hole S and the velocity V is needed.[0033] What is important here is that, if a pump capableof generating a higher pressure is used, there is a pos-

sibility that further-large amount of micro-nano bubblescan be generated. For example, it is available to use ahigh-pressure pump that generates pressures of 0.5 to250 MPa or so. If a pump of this kind is used, the liquidvelocity V increases proportionally to the pressure andthe amount of generation of micro-nano bubbles greatlyincreases because the impact power of the water ham-mering power F increases with the square of V. However,for the application of such high-pressure pump to an ap-paratus for generating micro-nano bubbles, it is difficultto meet various demands such as light weight, small size,metal-free, and low maintenance cost.[0034] In the present invention, by using the nozzlehaving a structure as illustrated in FIGS. 3 to 7, theamount of generation of micro-nano bubbles can bemade equal to or more than the conventional quantitywhen the pressure of squirting the dissolved liquid of thegas-liquid mixing state is the atmospheric pressure(about 0.1 MPa) or more. Further, setting the pressureto 0.2 MPa or higher makes it possible to generate micro-nano bubbles in an amount sufficient for performing cleanwashing and sterilizing. As mentioned above in thepresent invention, the lower limit of the squirting pressureof the dissolved liquid can be set to 0.2 MPa, a lowervalue than the conventional pressure. It therefore be-comes practicable to use a pump suitable for eliminatingmetal contamination, that is, the compressed-air drivenor electric-motor driven bellows cylinder pump 15 madeof fluorine resin, as shown in FIGS. 1 and 2. On the otherhand, if the squirting pressure of the dissolved liquid ex-ceeds 0.6 MPa while using the compressed-air driven orelectric-motor driven bellows cylinder pump of thepresent invention, the amount of generation of micro-na-no bubbles tends to be saturated. Therefore, the squirtingpressure of the dissolved liquid in the present inventionis preferred to be 0.2 to 0.6 MPa.[0035] The micro-nano bubble generating nozzle bythe present invention needs to have a diameter of 0.1 to6 mm at its nozzle parts 3b and 4b shown in FIG. 7 soas to squirt the jet of the dissolved liquid in a pressurehigher than the atmospheric pressure, preferably 0.2 to0.6 MPa, which are lower than conventional pressures.Here, the openings of the nozzle parts 3b and 4b, fromwhich the jet stream squirts, and the diameters of thenozzle parts 3b and 4b correspond to the "spout" and the"diameter of the small through-holes of the nozzle at thepart leading to the hollow of the cylinder" respectively,as the present invention defines. The reason for speci-fying the diameter of the nozzle parts 3b and 4b to be0.1 to 6 mm will be detailed in the description of embod-iment example later.[0036] The small-hole flow passages 3a and 4a areenough when they are such a device as has a stream-narrowing function for feeding the gas-dissolved liquid ina form of a high-speed jet; and when they are taper-shaped continuously toward the nozzle parts 3b and 4b,they may also be enough. The amount of generation ofmicro-nano bubbles is determined mainly by the dimen-

11 12

EP 3 009 184 A1

9

5

10

15

20

25

30

35

40

45

50

55

sion of the diameter of the nozzle parts 3b and 4b; there-fore, the small-hole flow passages 3a and 4a may beomitted in the present invention.[0037] An example of another method for colliding thegas-dissolved liquid will be explained referring to FIG. 8.Illustrated in FIG. 8 is the nozzle for generating micro-nano bubbles, which is comprised of a nozzle case 21,a micro-nano bubble discharging nozzle 22, and a base24, wherein one or more liquid-collision nozzles 23 areinstalled on the base 24.[0038] FIG. 9 is an enlarged view of the part where theliquid-collision nozzle 23 shown in FIG. 8 is disposed.FIG. 10 illustrates the shape of a single piece of the liquid-collision nozzle 23. A small-hole 23a opens toward thecenter of the liquid-collision nozzle 23. High-pressure liq-uid entering through this small-hole at a high-pressure inthe direction of the arrow Q collides in the center of theliquid-collision nozzle 23, generating micro-nano bub-bles.[0039] The experiment told that controlling the velocityof liquid V made the amount of generated micro-nanobubbles increased and prolonged the life of bubbles.When the velocity V exceeds 25 m/s as a guideline, thenozzle generates micro-nano bubbles stably.[0040] The same effect will be obtained at a lower liquidvelocity by squirting the liquid toward center from everydirection concentrating the water hammering at the cent-er. This means that when water hammering is given fromevery direction, the same or more effect will be producedeven if the velocity is reduced to 1/2. For example, sinceF = 2ρSV2, when eight holes are arranged so that thehammering among the jets concentrates in the center,the force at the center becomes F = ρS(1/2)2 x 8 = 2ρSV2.Thus, when the small-hole of the nozzle is provided in aplural number for concentrating the water hammeringproduced by the liquid collision, the energy of the liquidcollision becomes same even if the velocity V is low be-cause the flowing quantity of liquid increases. Since theamount of generation of micro-nano bubbles will be ac-ceptably same if the energy in the collisions of the liquidare same, the pressure of discharging the liquid can belowered and the amount of generation of micro-nano bub-bles will be secured as desired.[0041] FIG. 10 illustrates the shape of the liquid-colli-sion nozzles 23, wherein a small-hole 23a is made in thecircumference of the nozzle-cylinder part of the liquid-collision nozzle 23. Through this small-hole, the dis-solved liquid squirts to collide in the center and generatesmicro-nano bubbles. The micro-nano bubbles thus gen-erated is discharged toward the arrow Q. When a pluralityof the liquid-collision nozzle 23 is gather-arrayed, a largeamount of micro-nano bubbles are generated and aredischarged from a nozzle part 22a of the discharging noz-zle 22 illustrated in FIG. 8. As illustrated in FIG. 11, theshape of a liquid-collision nozzle 25 is such a shape ashas small-holes 25a in a multi-row configuration. For ex-ample therefore, when three places are provided for pro-ducing the water hammering by making holes in a three-

row configuration, it becomes practicable to generate mi-cro-nano bubbles in a large amount. Thus, this practiceis a useful method for miniaturization and increased ef-ficiency.[0042] Discharging the liquid from a plurality of holes,as the nozzle illustrated in FIG. 11, increases the intensityof the water hammering. Using this technique will notdecrease the amount of generation of micro-nano bub-bles even if the velocity V is low; and consequently apump with a high discharging pressure is not needed,which imposes less defrayment. Thus, this technique isindustrially very useful and permits development of a noz-zle having good efficiency.[0043] FIG. 12 is a cross sectional view of the gas-liquid mixing vessel 14. FIG. 13 is an enlarged view ofthe circled area E in FIG. 12. In a conventional gas-liquidmixing vessel, wherein gas and liquid are mixed under ahigh pressure, the mixture of gas and pure water is fedinto the gas-liquid mixing vessel by a pump and spoutedtherein upward like a water spout to merge the mixture.This method however is not efficient in mixing; thereforeit is necessary to generate micro-nano bubbles in an in-creased amount for improved efficiency.[0044] Then, as illustrated in FIG. 12, gas and liquidare fed by a pump in the direction of the arrow A towardthe arrow B and are introduced into gas-liquid injectionpipes 32 and 33. And as FIG. 13 illustrates, water ham-mering produced by colliding liquid in the directions fromthe arrow X and the arrow Y is used for increased effi-ciency of the mixing of the gas and liquid discharged froma hole of gas-liquid injection pipe 32a and a hole of gas-liquid injection pipe 33a of the gas-liquid injection pipe33. Thereby, mixing gas and liquid is performed efficientlyand gas-liquid mixture liquid as a raw material of micro-nano bubbles is produced speedily with increased merg-ing rate.[0045] A float 31 illustrated in FIG. 12 is provided forthe purpose of exhausting excessively entered gas tooutside if gas enters excessively in mixing gas and liquid.The float 31 exhausts entered excess gas safely andregulates the amount of gas and liquid to a proper level.This means that a certain situation is produced as de-scribed below. If there remains undissolved gas due tothe entering of excessive amount of gas, the gas will flowinto the nozzle and impedes the generation of micro-nanobubbles. The float eliminates this adverse effect of im-peding bubble generation and controls the amount ofgeneration of the micro-nano bubbles to a proper level,enabling sending bubbles stably.[0046] FIG. 14 illustrates a cross sectional view of apart of the float 31 shown in FIG. 12. The structure of thefloat pipe 31 comprises a float tip part 31a (which is ta-pered toward its end), a reinforcing rib 31b for preventionof collapse by the pressure of liquid, and a stop plug 31c.[0047] Mixing gas and liquid requires its method to in-crease the dissolving efficiency of gas into liquid by en-larging the contact area of gas and liquid. If the efficiencylowers, shortage of the generation amount occurs due

13 14

EP 3 009 184 A1

10

5

10

15

20

25

30

35

40

45

50

55

to a shortage of gas, which is a fatal problem in the gen-erating of micro-nano bubbles.[0048] We examined how much the amount of gener-ated micro-nano bubbles will be increased depending onthe degree of control over the amount of gas and liquid.As a result, it was understood that the following are thepoints. If the amount of liquid in the volume ratio insidethe gas-liquid mixing vessel occupies 60% and theamount of gas occupies 40%, the gas-liquid ratio is theideal balance of amounts. To stabilize the amount of gen-eration of the micro-nano bubbles and to increase theamount of generated bubbles, it is necessary that thecondition of the mixing of gas to be dissolved and liquidshould be optimized by exhausting the excess gas froman excess gas exhausting port 48 of a float socket 47using the buoyancy of the float 31 caused by the liquidfor controlling their ratio automatically. In the present in-vention, for the purpose of increasing greatly the amountof generation of micro-nano bubbles, it is preferable tocontrol the volume ratio of gas and liquid in the gas-liquidmixing vessel within the range of gas to liquid ratio = 50 :50 to 5 : 95 so that liquid will occupy more part in thevolume ratio. Also in the present invention, the float 31may be installed outside the gas-liquid mixing vessel,instead of installing inside. In this arrangement, connect-ing the inside and outside of the gas-liquid mixing vesselusing such as a communication pipe permits controllingthe volume ratio of gas and liquid.[0049] FIG. 15 is an example of a gas-liquid mixingvessel that has more improved efficiency. The fundamen-tal working is same as those illustrated in FIGS. 12 and13. This vessel is a gas-liquid mixing vessel structuredbased on a gas-liquid mixing vessel comprising a gas-liquid mixing vessel outer frame 36, a micro-nano bubblegenerating nozzle 38, and a member 40, wherein a struc-ture resistible to the internal pressure of the gas-liquidmixing vessel is given to the basic structure. The mixingof gas and liquid is efficiently performed inside that ves-sel.[0050] In FIG. 15, each of the reference numerals de-notes:

36: the gas-liquid mixing vessel outer frame;41: a float;35: a float holder;35a: an excess gas exhausting port on float holder;and41a: a float tip, wherein the float tip 41a has a functionthat regulates automatically the excess gas.

[0051] When using an conventional apparatus thatgenerates a less amount of micro-nano bubbles, a majormethod for generating an increased amount of micro-nano bubbles is as follows. The method is comprised ofprocesses of: generating micro-nano bubbles once in awater tank; pumping up micro-nano bubbles generatedin the water tank again; injecting additional gas to bedissolved into the pumped bubble-containing liquid at the

gas-liquid mixing vessel; and circulating the gas-injectedbubble-containing liquid multiple times to bring the bub-ble-containing liquid to a state in which a large amountof micro-nano bubbles are involved. Thereby, micro-na-no bubbles are generated in an increased amount.[0052] In this method, it is difficult to control the amountof generation of the micro-nano bubbles. Further, circu-lating technique invites a trouble such as occurrence ofcontamination. Because of that, an apparatus that is ca-pable of generating a large amount of micro-nano bub-bles in one process without use of circulation techniqueis desired.[0053] Therefore, it is intended to generate micro-nanobubbles, without circulation in the gas-liquid mixing ves-sel to be used in the present invention, by a liquid-collisionin the gas-liquid mixture state under the working of themicro-nano bubble generating nozzle 38, which is heldon a nozzle holder 39, having a structure same as illus-trated in FIG. 8.[0054] In this situation, it is the requisite condition thatthe nozzle 38 arranged inside the gas-liquid mixing ves-sel should issue the dissolved liquid of the gas-liquid mix-ture state at a flow rate more than that of the nozzle 11arranged at the distal end to increase the pressure insidethe gas-liquid mixing vessel. If the flow rate of the nozzle38 is smaller, micro-nano bubbles sometimes may notbe generated from the nozzle attached at the distal end.[0055] The effect of the installing of the nozzle 38 insidethe gas-liquid mixing vessel is that one-path of process-ing along the gas-liquid mixing vessel to the nozzle per-mits a stable generation of a large amount of micro-nanobubbles. Thereby, such technique enables provision ofan apparatus suitable for washing process in semicon-ductor manufacturing line for example.[0056] In the present invention, configuring gas-liquidmixing vessels in a multi-stage cascade makes it possibleto generate a larger amount of micro-nano bubbles; thisis a useful means for generating a large amount of bub-bles.[0057] FIG. 16 offers another method for generatingmicro-nano bubbles. This method employs an arrange-ment in which two or more small-hole nozzles 45 arearrayed perpendicular to the incoming or discharging di-rection (longitudinal direction) of the flow of the dissolvedliquid. This array is different from the parallel arrange-ment illustrated in FIG. 8. The arrangement illustrated inFIG. 16 has an advantage in that a desired flow rate iseasily ensured, because the small-hole nozzles are ar-rayed as the figure shows with respect to the outer cases42 and 43, a packing 46, and a nozzle hole 44; and there-by the small-hole nozzles become to have dischargingports on their both sides.[0058] As can be seen in FIG. 16, the gas-liquid mixtureliquid fed from the port IN is brought into a water ham-mering state by the nozzle 45 to generate micro-nanobubbles, and then discharged to the both sides of thenozzle. This ensures the flow rate as desired and theefficiency is doubled, therefore the energy needed for

15 16

EP 3 009 184 A1

11

5

10

15

20

25

30

35

40

45

50

55

generating micro-nano bubbles becomes half.[0059] Bubbles like this produced by a water hammer-ing gives less damage to the nozzle structure, becausecollision occurs only between the liquid. Therefore, it ispossible to make a bubble generating apparatus have alonger service life.[0060] The significant feature of the method and theapparatus for generating micro-nano bubbles by thepresent invention is that they are compatible with usingpure water as a dissolved liquid that does not include anyforeign matters such as nucleating agent in an applicationto washing and sterilization of semiconductor devicesand food. Granted that a use of nucleating agent, or thelike, is needed to increase the amount of generation ofmicro-nano bubbles, the quantity of addition of such ma-terial into pure water can be considerably reduced. In thepresent invention, tap water, well water, or spring watersuch as natural water other than pure water can be usedin consideration of the supply state or usability. Furtherin the present invention, the strengthening of the oxidiz-ing action of the dissolved liquid and the reformulating ofthe liquid for enhancing permeability required for impurityremoving action may be practicable to increase the ef-fectiveness of the washing and sterilizing.[0061] The method for strengthening the oxidizing ac-tion of the dissolved liquid stated above includes the useof the dissolved liquid which is an aqueous solution pre-pared by adding, to pure water, at least one of oxidantselected from the group consisting of ozone, oxygen, hy-drogen peroxide, chloric acid, perchloric acid, and potas-sium permanganate. Among these oxidant, ozone andoxygen are preferable oxidant for the present invention,because they have little adverse effect as an additive andtheir environmental load is very small.[0062] As the method for enhancing the permeabilityfor impurity removing action in the dissolved liquid statedabove, it is a preferable method to add a gas selectedfrom the group consisting of carbon dioxide, hydrogengas, and nitrogen gas, which has excellent permeabilityfor impurity removing action. On generation of micro-na-no bubbles, carbon dioxide, hydrogen gas, or nitrogengas invades easily the boundary surface between a sem-iconductor device and impurities, such as residuals ofresist, adhering to its surface. Thereby, the effectivenessof the washing is largely increased. Further, since carbondioxide or nitrogen gas is harmless to human body, suchgas is suitable for the present invention as a reformulatingadditive.[0063] The structure and shape of the micro-nano bub-ble generating nozzle by the present invention will bedetailed referring to concrete embodiments.

{First Embodiment}

[0064] FIG. 17 illustrates the structure and shape ofthe liquid-collision nozzle which was examined to gener-ate micro-nano bubbles using a water hammering power.FIG. 17A illustrates a comparative example to the em-

bodiment of the present invention and FIGS. 17B to 17Eillustrate embodiments of the present invention.[0065] FIG. 17A illustrates a configuration that a single-hole 49a is made in the circumference of a hollow cylin-der. In this comparative example, which has the single-hole 49a of one small through-hole, the dissolved liquidsquirted at a speed V collides against the wall of a pipe49. Therefore, the amount of generated micro-nano bub-bles is not much and there is a disadvantage in that theimpact by the collision against the wall may damage thewall.[0066] A liquid-collision nozzle illustrated in FIG. 17Bhas a two-hole 50a configured with two small through-holes. In this embodiment, the dissolved liquid squirtingat a speed V actualizes a collision at a speed of 2V, be-cause the two-hole 50a provides another spout at theopposite side. Thus, the collision energy becomes higherthan that of the comparison example of FIG. 17A.[0067] A liquid-collision nozzle illustrated in FIG. 17Chas a three-hole 51a configured with three small through-holes. In this embodiment, the dissolved liquid squirts ata speed V from three holes provided at an interval of 120degree for collision. Thereby, the energy in the center ofcollision of the liquid squirted at a speed V becomes threetimes. This means that, when the collision is producedusing three spouts and when the collision energy sameas the one in the former two-hole case is considered tobe enough, the collision produces still the same amountof energy even if the speed V is reduced by as much as20%. Since the pump pressure determines the speed V,even a lowered pump pressure is still capable of gener-ating micro-nano bubbles.[0068] A liquid-collision nozzle illustrated in FIG. 17Dhas a four-hole 52a configured with four small through-holes. In this embodiment, the dissolved liquid squirts ata speed V from four holes provided at an interval of 90degree for collision. Thereby, the energy in the center ofcollision of the liquid squirted at a speed V becomes fourtimes. This means that, when the collision is producedusing four spouts and when the collision energy sameas the one in the former two-hole case is considered tobe enough, the collision produces still the same amountof energy even if the speed V is reduced by as much as30%. Since the pump pressure determines the speed V,even a lowered pump pressure is still capable of gener-ating micro-nano bubbles.[0069] A liquid-collision nozzle illustrated in FIG. 17Ehas a five-hole 53a configured with five small through-holes. In this embodiment, the dissolved liquid squirts ata speed V from five holes provided at an interval of 72degree for collision. Thereby, the energy in the center ofcollision of the liquid squirted at a speed V becomes fivetimes. This means that, when the collision is producedusing five spouts and when the collision energy same asthe one in the former two-hole case is considered to beenough, the collision produces still the same amount ofenergy even if the speed V is reduced by as much as40%. Since the pump pressure determines the speed V,

17 18

EP 3 009 184 A1

12

5

10

15

20

25

30

35

40

45

50

55

even a lowered pump pressure is still capable of gener-ating micro-nano bubbles.[0070] As stated above, micro-nano bubbles, whichwere not generated without a high-pressure pump, canbe generated in a large amount by optimizing the struc-ture and arrangement of the through-hole of the liquid-collision nozzle even if the pump pressure is 0.2 MPa;thus this technique is able to actualize energy-saving.

{Second Embodiment}

[0071] Referring to FIG. 18, the following explains adiameter-related feature in the liquid-collision nozzle bythe present invention that generates micro-nano bubble.The explanation describes the relationship between thediameter of a micro-nano bubble discharging port to beprovided on the end of a hollow cylinder and the diameterof the hollow cylinder at its part where a through-hole isarranged in the circumferential direction.[0072] FIG. 18A illustrates a liquid-collision nozzle hav-ing two holes 54a. In a nozzle cylinder 54, the diameterof the part (the part in which the small through-hole ismade) against which the jet of liquid collides is madelarge, referred to as D1, and the diameter of a dischargingport is made small, referred to as D2. With this configu-ration, pressure is immediately imposed on micro-nanobubbles generated by the collision. Thereby, the compo-sition of micro-nano bubbles can be controlled. That is,this diameter configuration works as a means for control-ling the distribution of particles in micro-nano bubblesand therefore an advantageous effect is brought in theminiaturization of particles.[0073] A liquid-collision nozzle illustrated in FIG. 18Bhas two holes 55a. In a nozzle cylinder 55, the diameterof the part against which the jet of liquid collides is madesmall, referred to as D3, and the diameter of a dischargingport is made large, referred to as D4. With this configu-ration, pressure is not imposed on micro-nano bubblesgenerated by the collision. Therefore, the distribution ofparticles of micro-nano bubbles which expand on gener-ation becomes a little large.[0074] In the present invention, either of the nozzleshaving the structure illustrated in FIG. 18 may be used.The nozzle cylinder shown in FIG. 18A has such a struc-ture that the diameter of the discharging port is smallerthan the diameter of the collision occurring part of thenozzle cylinder; therefore, the pressure of the dissolvedliquid in the vicinity of the spout becomes high. Becauseof that, even though there is an advantageous effect forminiaturization of micro-nano bubble particles, the bub-ble generation is a little bit impeded. As a consequenceto this, the lowering of the amount of generated bubbles,or the late-generating of bubbles at a place away fromthe spout, may occur. In contrast to this, the nozzle havingthe structure illustrated in FIG. 18B is able to generate alarge amount of bubbles stably, because the nozzle al-lows pressure release at its discharging port. Since it ispossible to regulate the miniaturization of micro-nano

bubbles by the diameter of the small through-hole of thenozzle, the nozzle illustrated in FIG. 18B is suitable.

{Third Embodiment}

[0075] Regarding a liquid-collision nozzle illustrated inFIG. 18B, the relationship between the diameter of theliquid-collision nozzle and micro-nano bubbles is ex-plained referring to FIGS. 19 to 21, wherein the pressureis kept constant and pure water, which includes 50 ppmof ozone, is used as the dissolved liquid.[0076] FIG. 19 illustrates the relationship between theflow rate of the jet squirted from the small through-holeof a nozzle 56 and the flow rate of the discharge issuedfrom the discharge port. In FIG. 19, the dissolved liquidsquirted from a small through-hole 56a at a speed V1,after its squirting from a single-hole 56a at a liquid rateQ1 per second, collides to generate micro-nano bubbles.Then, it goes out from the discharge port of the nozzle56 at a speed V2 with a liquid rate Q2 per second. Here,the flow rates Q1 and Q2 are same.[0077] FIG. 20 shows the relationship between the di-ameter of the small through-hole of the liquid-collisionnozzle and the amount of generation of micro-nano bub-bles. In this graph, the amount of generated micro-nanobubbles is plotted in the number of bubbles generatedper unit volume of the dissolved liquid. As can be knownfrom FIG. 20, when the diameter of the small through-hole of the liquid-collision nozzle becomes larger, V1 re-duces and the liquid rate Q1 increases. In this case, theamount of generated micro bubbles (60 mm or larger indiameter) increases but the amount of generated nanobubbles reduces. On the other hand, when the diameterof a liquid-collision nozzle becomes smaller, the liquidrate Q1 reduces. In this case, the amount of generatedmicro bubbles (60 mm or larger in diameter) reduces andV1 increases, but the amount of generated nano bubbles(2 mm or smaller in diameter) increases.[0078] Thus, the diameter of the small through-hole ofthe liquid-collision nozzle is an important factor that de-termines the performance of the micro-nano bubbles. Al-though there is a difference in behavior depending onthe nature of the liquid and the gas to be dissolved, thetendency is as described in the above. Therefore, theamount of micro-nano bubbles can be controlled by ad-justing the diameter of the small through-hole of the liq-uid-collision nozzle.[0079] FIG. 21 shows the relationship between the di-ameter of the small through-hole of the liquid-collisionnozzle and the flow rate Q. Where the liquid pressure iskept constant, the flow rate Q is proportional to the squareof the diameter of the small through-hole of the liquid-collision nozzle, but the liquid speed V is inversely pro-portional to the square of the diameter of the liquid-col-lision nozzle. Thus, the relationship between the diame-ter of one single-hole of the small through-hole of theliquid-collision nozzle and the flow rate Q is as shown inFIG. 20. The optimization of the diameter of the small

19 20

EP 3 009 184 A1

13

5

10

15

20

25

30

35

40

45

50

55

through-hole of the nozzle is possible by determining thenumber of holes of the liquid-collision nozzles in view ofthe required flow rate.[0080] As can be known from FIG. 20, it is necessaryin the present invention that the small through-hole of thenozzle should have a diameter of 0.1 to 6.0 mm. If thediameter of the small through-hole of the nozzle is smallerthan 0.1 mm, the amount of generation of small-size bub-bles of about 60 mm or smaller in particle diameter in-creases. However, the amounts of generation of bubbleshaving larger diameters than that particle diameter de-creases sharply; then, micro-nano bubbles are hardlygenerated. In addition, if the diameter of the smallthrough-hole of the nozzle is in excess of 6 mm, the totalamount of generated bubbles increases. On the contraryhowever, the amount of generation of small-size bubblesof about 60 mm or smaller in particle diameter decreasessharply to 500 bubbles per mL or less; thus, it is not pos-sible to achieve a sufficient effect of the present invention.It is more preferable in the present invention that the di-ameter of the small through-hole of the liquid-collisionnozzle should be configured within a range of 0.1 to 3mm to generate micro-nano bubbles in a large amountof 1000 bubbles per mL or more.

{Fourth Embodiment}

[0081] Micro-nano bubbles were generated using dis-tilled water as the dissolved liquid with the apparatus forgenerating micro-nano bubbles by the present inventionas illustrated in FIGS. 1 and 2. The nozzle used had thesame structure as illustrated in FIGS. 3 and 4, and thenozzle parts 3b and 4b were given a straight shape of asmall through-hole of 0.5 mm in diameter. In addition, asa comparison example, micro-nano bubbles were gen-erated by the conventional gas-liquid two-phase swirlflow method using, similarly to the above, distilled wateras the dissolved liquid. FIGS. 22 and 23 show the rela-tionship between the amount of generated bubbles andthe particle diameter of bubbles. FIG. 22 shows theamount generated by the method for generating micro-nano bubbles by the present invention and FIG. 23 showsthe same using the gas-flow two-phase swirl flow meth-od. The amount of generated bubbles is indicated in thenumber of bubbles per unit volume of the distilled water(bubble/mL). The amount of generated bubbles and theirparticle diameter are determined using a submerged par-ticle counter at room temperature. FIGS. 22 and 23 donot show the amount of bubbles having particle diame-ters in the nano region; this is because of the difficulty inmeasuring the number of particles in the nano region withan optical method.[0082] Comparison of the results shown in FIGS. 22and 23 teaches that the method for generating micro-nano bubbles by the present invention generates largeramount of bubbles compared to the amount generatedby the conventional gas-liquid two-phase swirl flow meth-od over the entire particle diameter region of about 60

mm or smaller. Particularly, the difference in the regionof the bubble particle diameter of 20 to 40 mm is consid-erable. In addition, comparison of both methods for theregion of the bubble particle diameter of 2 to 10 mm tellsthat the generated bubbles by the present invention isequal to or slightly larger than that by the conventionalmethod in the amount. By analogy from the results of thenumber of generated bubbles in the region of a smallparticle diameter, the present invention can be consid-ered to be a method that generates a large number ofbubbles in the sub-micron region, i.e., even in the nanoregion. A use of the apparatus for generating micro-nanobubbles by the present invention for the washing semi-conductor wafers and the sterilization of food such asvegetables actually has confirmed that the effect of wash-ing or sterilization continued even when the dissolvedliquid became an apparent-clear solution over time, likea bubble-disappeared liquid. This means that the presentinvention gains an effect of being able to continue ren-dering a washing and sterilization effect by generatingmicro-nano bubbles, for a long time more than the con-ventional method would provide. It is understood that theexistence of nano-bubbles, which is large in amount, hav-ing smaller diameter of less than 1mm has produced suchan effect.[0083] As stated above, the method for generating mi-cro-nano bubbles by the present invention generates mi-cro-nano bubbles using the water hammering power.Therefore, the method is able to generate micro-nanobubbles in a large amount using pure water only withoutuse of substances which are not necessarily neededsuch as nucleating agents. Accordingly, the method canrealize a clean washing and sterilization. Since this waterhammering power is maximized by the use of a bubblegenerating nozzle having an optimized structure andshape and by an apparatus that is able to stably performthe generation of a large amount of bubbles, the appli-cation of such combination makes it possible to performcontinuous and stable generation of bubbles in an effi-cient manner. Thereby, the amount of generation ofsmall-size bubbles, not only of the size of micrometerorder but also of nanometer order, can be increased to-gether. This feature enhances the capability and functionin the washing and sterilizing more than those in conven-tional technique.[0084] Further, for a clean washing that is incompatiblewith metal ion which a wetted part generates, configuringa pump or piping, or both, in a washing apparatus withplastic or preferably with fluorine resin makes the appa-ratus become to have high reliability and clean feature.Thus, the apparatus for generating micro-nano bubblesby the present invention is applicable to the clean wash-ing for such as semiconductor wafers. Conventionally,the washing of semiconductor wafers has used process-ing with such as strong acid treatment, alkaline neutral-ization, and pure water rinsing. The process thereforehas been complicated and the environmental load hasbeen large because, for example, the process uses drug

21 22

EP 3 009 184 A1

14

5

10

15

20

25

30

35

40

45

50

55

solutions. However, the present invention is able to solvethis problem. Further, the process burden such as in thedisposal of drug solutions is eliminated and the requiredscale for semiconductor manufacturing equipment be-comes small and related process is made compact; theseare a great industrial value.[0085] Further, in the semiconductor wafer washing,the use of a micro-nano bubble-generated liquid, otherthan pure water, improves the washing effect largely andmakes the washing process very simple with the washingequipment downsized. The micro-nano bubble-generat-ed liquid for such use is prepared by adding a gas havingexcellent oxidizing ability like oxygen or a permeable im-purity removal agent such as carbon dioxide or nitrogengas, and then followed by the micro-nano bubble gener-ation process by the present invention. Thereby, thewashing becomes environment friendly. Further, theprocess burden such as in the disposal of drug solutionsis eliminated and the required scale for semiconductormanufacturing equipment becomes small and relatedprocess is made compact; these are a great industrialvalue.[0086] The micro-nano bubble generating system bythe present invention is applicable to medical use, be-cause the system uses micro-nano bubbles generatedby a clean system that uses pumps and wetted part madeof fluorine resin. Therefore, it is expected that the field ofthe application of the invented system will expand greatly.[0087] Further, the capability of the washing and ster-ilization by micro-nano bubbles that uses oxygen orozone as its constitution gas can be applied not only tothe semiconductor field but also to fields of foods andvegetables. Thus, there is a possibility in that the appli-cation range may expand to the fields such as agricultureand the fishery; and the method for generating micro-nano bubbles, the bubble generating nozzle, and the ap-paratus for generating micro-nano bubbles by thepresent invention have a very high superiority in suchfield expansion movement.

Claims

1. A method for generating micro-nano bubbles,wherein the method uses water hammering powerthat is produced by mutual collision of jets of a solu-tion, which includes dissolved gas, squirted out fromeach of two or more spouts.

2. The method for generating micro-nano bubbles ac-cording to claim 1, wherein the method uses waterhammering power to generate micro-nano bubbles,wherein micro-nano bubbles are generated by a mu-tual collision of jets of a dissolved liquid of a gas-liquid mixture state; the collision of jets is createdinside a cylinder that has two or more small through-holes; and the jets of the dissolved liquid are pro-duced by injecting the liquid from the outside of the

cylinder via the small through-holes in the cylinderat a pressure higher than the atmospheric pressure.

3. The method for generating micro-nano bubbles ac-cording to claim 2, comprising:

a sucking process that sucks gas and liquid;a pressurization process that pressurizes gasand liquid;a dissolved gas enriching process, wherein thepressurized gas-including liquid is mixed withanother new gas; anda dissolved gas miniaturization process thatgenerates micro-nano bubbles,wherein a dissolved liquid of a gas-liquid mixturestate prepared at the dissolved gas enrichingprocess is injected from the outside of the cyl-inder having two or more small through-holes,via such small through-holes at a pressure high-er than the atmospheric pressure to produce jetsof the liquid, and the jets are collided mutuallyinside the cylinder.

4. The method for generating micro-nano bubbles ac-cording to any of claims 1 to 3, wherein the pressureof being more than the atmospheric pressure at thetime of squirting is 0.2 to 0.6 MPa, and the diameterof the small through-holes at the part leading to thehollow of the cylinder is 0.1 to 6.0 mm.

5. The method for generating micro-nano bubbles ac-cording to any of claims 1 to 4, wherein the dissolvedliquid is an aqueous solution that includes at leastone of substance selected from the group consistingof ozone, oxygen, hydrogen peroxide, chloric acid,perchloric acid, and potassium permanganate.

6. The method for generating micro-nano bubbles ac-cording to any of claims 1 to 4, wherein the dissolvedliquid is an aqueous solution that includes a sub-stance selected from the group consisting of carbondioxide, hydrogen gas, and nitrogen gas.

7. A bubble generating nozzle for use in the generatingof micro-nano bubbles using water hammering pow-er, comprising:

a hollow cylinder having two or more smallthrough-holes arrayed in the circumferential di-rection thereof anda micro-nano bubble discharge port provided onat least one end of the hollow cylinder,wherein the small through-holes are arrangedso that all of their extension lines passingthrough respective center of the cross-sectionof each of the small through-holes intersect eachother in the inside of the hollow of the cylinder.

23 24

EP 3 009 184 A1

15

5

10

15

20

25

30

35

40

45

50

55

8. The bubble generating nozzle for generating micro-nano bubbles according to claim 7, wherein the noz-zle has two or more numbers of hollow cylinders.

9. The bubble generating nozzle for generating micro-nano bubbles according to claim 8, wherein the hol-low cylinders of two or more numbers are arrangedin parallel to or perpendicular to the direction of theinflow or the discharge of the flow of the dissolvedliquid.

10. The bubble generating nozzle for generating micro-nano bubbles according to any of claims 7 to 9,wherein the hollow cylinder has, in its longitudinaldirection, a multi-row of two or more rows of smallthrough-holes, and each of such rows consists oftwo or more small through-holes.

11. The bubble generating nozzle for generating micro-nano bubbles according to any of claims 7 to 10,wherein the diameter of the small through-hole atthe part that leads to the hollow of the hollow cylinderis 0.1 to 6.0 mm.

12. The bubble generating nozzle for generating micro-nano bubbles according to any of claims 7 to 11,wherein the diameter of the micro-nano bubble dis-charge port provided on at least one end of the hollowcylinder is equal to or larger than the diameter of apart of the hollow cylinder, wherein such part is sucha part where the small through-holes are arrangedin a circumferential direction.

13. An apparatus for generating micro-nano bubbles,comprising:

a means for sucking each of gas and liquid;a means for pressurizing the gas and the liquidin a lump and transferring them;a gas-liquid mixing vessel for enriching the dis-solved gas by mixing the transferred liquid,which includes the gas, with another new gas;anda means for generating micro-nano bubbles inthe gas-liquid mixing vessel using the dissolvedliquid of the gas-liquid mixing state, wherein themeans has the bubble generating nozzle forgenerating micro-nano bubbles as described inany of claims 7 to 12.

14. The apparatus for generating micro-nano bubblesaccording to claim 13, wherein, in the means for gen-erating micro-nano bubbles, the dissolved liquid issquirted at a pressure of 0.2 to 0.6 MPa through thesmall through-hole of the bubble generating nozzle.

15. The apparatus for generating micro-nano bubblesaccording to claims 13 or 14, wherein the gas-liquid

mixing vessel has the bubble generating nozzle forgenerating micro-nano bubbles, and the liquid thatincludes the gas transferred by the means for pres-surizing and transferring is discharged into the gas-liquid mixing vessel by the bubble generating nozzle.

16. The apparatus for generating micro-nano bubblesaccording to any of claims 13 to 15, wherein the gas-liquid mixing vessel has a float valve inside or outsidethe vessel to maintain the volume of the gas and theliquid and the internal pressure inside the vessel al-ways within a prescribed range by discharging ex-cess gas from the vessel.

17. The apparatus for generating micro-nano bubblesaccording to any of claims 13 to 16, wherein a pumpor piping, or both, through which the gas-liquid mix-ture liquid flows, is made of plastic.

18. The apparatus for generating micro-nano bubblesaccording to claim 17, wherein a pump or piping, orboth, through which the gas-liquid mixture liquidflows, is made of fluorine resin.

19. The apparatus for generating micro-nano bubblesaccording to any of claims 13 to 18, wherein themeans for pressurizing and transferring the liquidthat includes the gas is an apparatus that uses acompressed-air driven or an electric motor drivenbellows cylinder pump.

20. The apparatus for generating micro-nano bubblesaccording to any of claims 13 to 19, wherein the dis-solved liquid is an aqueous solution that includes atleast one of substance selected from the group con-sisting of ozone, oxygen, hydrogen peroxide, chloricacid, perchloric acid, and potassium permanganate.

21. The apparatus for generating micro-nano bubblesaccording to any of claims 13 to 19, wherein the dis-solved liquid is an aqueous solution that includes asubstance selected from the group consisting of car-bon dioxide, hydrogen gas, and nitrogen gas.

Amended claims under Art. 19.1 PCT

1. A method for generating micro-nano bubbles,wherein the method uses water hammering powerto generate micro-nano bubbles, wherein micro-na-no bubbles are generated by a mutual collision ofjets of a dissolved liquid of a gas-liquid mixture state;the collision of jets is created inside a cylinder havingtwo or more small through-holes arrayed in the cir-cumferential direction thereof with such a configura-tion that the respective opening of such two or moresmall through-holes are arranged facing each otherin the same plane; and the jets of the dissolved liquid

25 26

EP 3 009 184 A1

16

5

10

15

20

25

30

35

40

45

50

55

are produced by injecting the liquid from the outsideof the cylinder via the small through-holes in the cyl-inder at a pressure higher than the atmospheric pres-sure.

2. The method for generating micro-nano bubblesaccording to claim 1, comprising:

a sucking process that sucks gas and liquid;a pressurization process that pressurizes gasand liquid;a dissolved gas enriching process, wherein thepressurized gas-including liquid is mixed withanother new gas; anda dissolved gas miniaturization process thatgenerates micro-nano bubbles,wherein a dissolved liquid of a gas-liquid mixturestate prepared at the dissolved gas enrichingprocess is injected from the outside of the cyl-inder having two or more small through-holesarrayed in the circumferential direction thereofwith such a configuration that the respectiveopening of such two or more small through-holesare arranged facing each other in the sameplane via such small through-holes at a pressurehigher than the atmospheric pressure to pro-duce jets of the liquid, and the jets are collidedmutually inside the cylinder.

3. The method for generating micro-nano bubblesaccording to claim 1 or claim 2, wherein the pressureof being more than the atmospheric pressure at thetime of squirting is 0.2 to 0.6 MPa, and the diameterof the small through-holes at the part leading to thehollow of the cylinder is 0.1 to 6.0 mm.

4. The method for generating micro-nano bubblesaccording to any of claims 1 to 3, wherein the dis-solved liquid is an aqueous solution that includes atleast one of substance selected from the group con-sisting of ozone, oxygen, hydrogen peroxide, chloricacid, perchloric acid, and potassium permanganate.

5. The method for generating micro-nano bubblesaccording to any of claims 1 to 3, wherein the dis-solved liquid is an aqueous solution that includes asubstance selected from the group consisting of car-bon dioxide, hydrogen gas, and nitrogen gas.

6. A bubble generating nozzle for use in the gener-ating of micro-nano bubbles using water hammeringpower, comprising:

a hollow cylinder having two or more smallthrough-holes arrayed in the circumferential di-rection thereof with such a configuration that therespective opening of each of such two or moresmall through-holes faces each other in the

same plane anda micro-nano bubble discharge port provided onat least one end of the hollow cylinder,wherein the small through-holes are arrangedso that all of their extension lines passingthrough respective center of the cross-sectionof each of the small through-holes intersect eachother in the inside of the hollow of the cylinder.

7. The bubble generating nozzle for generating mi-cro-nano bubbles according to claim 6, wherein thenozzle has two or more numbers of hollow cylinders.

8. The bubble generating nozzle for generating mi-cro-nano bubbles according to claim 7, wherein thehollow cylinders of two or more numbers are ar-ranged in parallel to or perpendicular to the directionof the inflow or the discharge of the flow of the dis-solved liquid.

9. The bubble generating nozzle for generating mi-cro-nano bubbles according to any of claims 6 to 8,wherein the hollow cylinder has, in its longitudinaldirection, a multi-row of two or more rows of smallthrough-holes, and each of such rows consists oftwo or more small through-holes.

10. The bubble generating nozzle for generating mi-cro-nano bubbles according to any of claims 6 to 9,wherein the diameter of the small through-hole atthe part that leads to the hollow of the hollow cylinderis 0.1 to 6.0 mm.

11. The bubble generating nozzle for generating mi-cro-nano bubbles according to any of claims 6 to 10,wherein the diameter of the micro-nano bubble dis-charge port provided on at least one end of the hollowcylinder is equal to or larger than the diameter of apart of the hollow cylinder, wherein such part is sucha part where the small through-holes are arrangedin a circumferential direction.

12. An apparatus for generating micro-nano bub-bles, comprising:

a means for sucking each of gas and liquid;a means for pressurizing the gas and the liquidin a lump and transferring them;a gas-liquid mixing vessel for enriching the dis-solved gas by mixing the transferred liquid,which includes the gas, with another new gas;anda means for generating micro-nano bubbles inthe gas-liquid mixing vessel using the dissolvedliquid of the gas-liquid mixing state, wherein themeans has the bubble generating nozzle forgenerating micro-nano bubbles as described inany of claims 6 to 11.

27 28

EP 3 009 184 A1

17

5

10

15

20

25

30

35

40

45

50

55

13. The apparatus for generating micro-nano bub-bles according to claim 12, wherein, in the meansfor generating micro-nano bubbles, the dissolved liq-uid is squirted at a pressure of 0.2 to 0.6 MPa throughthe small through-hole of the bubble generating noz-zle.

14. The apparatus for generating micro-nano bub-bles according to claims 12 or 13, wherein the gas-liquid mixing vessel has the bubble generating noz-zle for generating micro-nano bubbles, and the liquidthat includes the gas transferred by the means forpressurizing and transferring is discharged into thegas-liquid mixing vessel by the bubble generatingnozzle.

15. The apparatus for generating micro-nano bub-bles according to any of claims 12 to 14, wherein thegas-liquid mixing vessel has a float valve inside oroutside the vessel to maintain the volume of the gasand the liquid and the internal pressure inside thevessel always within a prescribed range by discharg-ing excess gas from the vessel.

16. The apparatus for generating micro-nano bub-bles according to any of claims 12 to 15, wherein apump or piping, or both, through which the gas-liquidmixture liquid flows, is made of plastic.

17. The apparatus for generating micro-nano bub-bles according to claim 16, wherein a pump or piping,or both, through which the gas-liquid mixture liquidflows, is made of fluorine resin.

18. The apparatus for generating micro-nano bub-bles according to any of claims 12 to 17, wherein themeans for pressurizing and transferring the liquidthat includes the gas is an apparatus that uses acompressed-air driven or an electric motor drivenbellows cylinder pump.

19. The apparatus for generating micro-nano bub-bles according to any of claims 12 to 18, wherein thedissolved liquid is an aqueous solution that includesat least one of substance selected from the groupconsisting of ozone, oxygen, hydrogen peroxide,chloric acid, perchloric acid, and potassium perman-ganate.

20. The apparatus for generating micro-nano bub-bles according to any of claims 12 to 18, wherein thedissolved liquid is an aqueous solution that includesa substance selected from the group consisting ofcarbon dioxide, hydrogen gas, and nitrogen gas.

29 30

EP 3 009 184 A1

18

EP 3 009 184 A1

19

EP 3 009 184 A1

20

EP 3 009 184 A1

21

EP 3 009 184 A1

22

EP 3 009 184 A1

23

EP 3 009 184 A1

24

EP 3 009 184 A1

25

EP 3 009 184 A1

26

EP 3 009 184 A1

27

EP 3 009 184 A1

28

EP 3 009 184 A1

29

EP 3 009 184 A1

30

EP 3 009 184 A1

31

EP 3 009 184 A1

32

EP 3 009 184 A1

33

EP 3 009 184 A1

34

EP 3 009 184 A1

35

EP 3 009 184 A1

36

EP 3 009 184 A1

37

EP 3 009 184 A1

38

EP 3 009 184 A1

39

EP 3 009 184 A1

40

EP 3 009 184 A1

41

5

10

15

20

25

30

35

40

45

50

55

EP 3 009 184 A1

42

5

10

15

20

25

30

35

40

45

50

55

EP 3 009 184 A1

43

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the Europeanpatent document. Even though great care has been taken in compiling the references, errors or omissions cannot beexcluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• WO TOKKAI2009274045 A [0006]• WO TOKKAI2008264771 A [0006]

• WO 4547451 A [0006]• WO 4924907 A [0006]