JP2008212788A - Cleaning apparatus and cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning apparatus and a cleaning method having improved cleaning efficiency at the time of cleaning a solid body surface by jetting a liquid in which foams are generated. <P>SOLUTION: The cleaning apparatus comprises a liquid introduction part 11 for introducing a liquid; a gas introduction part 12 for mixing a gas to the liquid introduced by the liquid introduction part; a reversely tapered nozzle part 14 composed of a narrowed part having a narrowed fluid cross sectional surface area and a reversely tapered part having gradually widened fluid cross sectional surface area in the flow direction of the gas-liquid mixed fluid for generating a large number of very small foams of the gas introduced from the gas introduction part; a cleaning nozzle 10 having a jetting outlet 17 for jetting the produced gas-liquid mixed fluid containing a large number of the very small foams to an object to be washed; liquid supply means for supplying a liquid for washing to the liquid introduction part of the cleaning nozzle; and gas supply means for introducing a gas to the gas introduction part of the cleaning nozzle for mixing the gas to the liquid introduced by the liquid introduction part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning apparatus and a cleaning method useful for cleaning a solid surface such as a glass substrate, and more particularly, to a cleaning nozzle having a predetermined shape capable of maintaining a high void ratio in a liquid directly injected onto an object to be cleaned. The present invention relates to a cleaning apparatus and a cleaning method.

  Conventionally, in order to remove contaminants adhering to a solid surface, a liquid such as water, a surfactant, an organic solvent, or the like is used as a cleaning liquid, and the cleaning is generally performed by injecting the liquid onto a cleaning surface. However, cleaning with water alone has a weak cleaning effect. When a surfactant, an organic solvent, or the like is used, the cleaning effect is improved, but cleaning waste liquid is required and the environmental load is high.

Therefore, as a method for enhancing the cleaning effect without using a surfactant or an organic solvent, a cleaning method is known in which water containing fine bubbles generated by a cavity phenomenon is sprayed onto the object to be cleaned. (For example, refer to Patent Document 1). This cleaning method is performed by supplying high-pressure water using a nozzle having a portion where the cross-sectional area spreads rapidly.
Japanese Patent Laid-Open No. 5-317815

  However, in a cleaning apparatus that generates bubbles by such a cavity phenomenon (cavitation) and injects a liquid, the void ratio of bubbles contained in the liquid is limited to about 10%, and a cleaning apparatus with a higher cleaning effect is available. It was sought after.

  The present invention has been made to solve such a problem, and further improves the cleaning efficiency when cleaning the solid surface by injecting the liquid in which bubbles are generated. It is an object to provide a cleaning apparatus and a cleaning method that can be reliably performed.

  The cleaning device according to the present invention includes a liquid introduction part that introduces liquid, a gas introduction part that mixes gas into the liquid introduced from the liquid introduction part, a throttle part that narrows a flow cross-sectional area, and a flow direction of the gas-liquid mixed fluid. It is composed of a divergent part with a gradually increasing flow cross-sectional area, and cleans a divergent nozzle part that generates a large number of microbubbles from the gas introduced from the gas introduction part, and a gas-liquid mixed fluid containing a large number of generated microbubbles A cleaning nozzle having an injection port for injecting the object, a liquid supply means for supplying a liquid used for cleaning to a liquid introducing portion of the cleaning nozzle, and a cleaning for mixing gas into the liquid introduced from the liquid introducing portion Gas supply means for introducing gas into the gas introduction part of the nozzle.

  In addition, another cleaning apparatus of the present invention includes a liquid introduction unit that introduces a liquid, a self-contained gas introduction unit that mixes gas into the liquid introduced from the liquid introduction unit, a throttle unit that narrows the flow cross-sectional area, and a gas It consists of a divergent part whose flow cross-sectional area gradually increases in the flow direction of the liquid mixture fluid, and contains a divergent nozzle part that generates a large number of microbubbles from the gas introduced from the gas introduction part, and a large number of generated microbubbles And a liquid supply means for supplying a liquid used for cleaning to a liquid introducing portion of the cleaning nozzle. .

  The cleaning method of the present invention includes a liquid introduction step for introducing a liquid, a gas introduction step for mixing a gas into the liquid introduced from the liquid introduction step, and a gas-liquid formed after a throttle portion that narrows the flow cross-sectional area. A micro-bubble generating process for causing a gas-liquid mixed fluid to pass through a divergent part where the flow cross-sectional area gradually increases in the flow direction of the mixed fluid and generating a large number of micro-bubbles from the gas introduced from the gas introduction part, And an injection step of injecting the gas-liquid mixed fluid containing microbubbles onto the object to be cleaned.

  The cleaning device of the present invention is characterized by the cleaning nozzle used, and the configuration of the microbubble generating unit in the cleaning nozzle is such that the nozzle body having the microbubble generating unit includes a throttle unit that narrows the flow cross-sectional area. And a divergent portion where the flow cross-sectional area gradually increases in the flow direction of the gas-liquid mixed fluid. With such a structure, a pressure difference is generated in the flow direction of the gas-liquid mixed fluid to generate a turbulent flow, whereby the bubbles made of the gas introduced into the liquid are sheared to generate a large number of microbubbles. More preferably, the microbubble generator has a conical shape, and a venturi type that expands in the flow direction of the gas-liquid mixed fluid can be used.

  Furthermore, from the viewpoint of energy saving, it is desirable that the opening angle of the divergent part in the microbubble generating part is narrower (the pressure of the liquid to be introduced can be reduced), and the opening angle of the divergent part is less than 40 degrees, Furthermore, it is preferably 20 degrees or less.

  Here, the gas introduction part provided in the cleaning nozzle may be either forcedly introduced or naturally sucked in gas, and can be selected according to the actual situation. The forced introduction means that the gas is not naturally sucked, and includes, for example, introducing the gas into the liquid while applying pressure using a compressor. By forcibly introducing the gas, the gas-liquid ratio can be arbitrarily set or adjusted, or the gas ratio in the liquid can be increased. It is also possible to control the diameter of the generated microbubbles by controlling the flow rate ratio.

  In the case of natural suction, a self-contained suction type gas introduction port is provided in the cleaning nozzle immediately before the microbubble generation unit, and the liquid introduced by the liquid introduction unit moves to generate microbubbles. What is necessary is just to make it suck | suck naturally by utilizing the effect | action which a pressure falls in the throttle part which narrows the provided flow cross-sectional area.

  According to the cleaning apparatus and the cleaning method of the present invention, it is possible to inject a liquid containing a large amount of microbubbles as a cleaning liquid, thereby enabling effective cleaning with high cleaning efficiency. In addition, compared with conventional cleaning, when the same cleaning effect is to be obtained, the liquid supply pressure can be reduced, so that energy consumption is reduced, and the amount of liquid used can be reduced, resulting in low cost. In addition, effects such as reduction of environmental load can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic view showing a configuration of a cleaning apparatus according to the present invention, and FIG. 2 is a schematic cross-sectional view showing a configuration example of a cleaning nozzle according to the present invention. FIG. 3 is a schematic diagram for explaining a cleaning mechanism using micro bubbles during cleaning.

  First, the cleaning apparatus 1 of this embodiment mixes gas into the cleaning nozzle 2, the liquid supply means 3 that supplies the liquid used for cleaning to the liquid introducing portion of the cleaning nozzle 2, and the liquid introduced from the liquid introducing portion. For this purpose, gas supply means 4 for introducing gas into the gas introduction part of the cleaning nozzle 2 is provided.

  The cleaning nozzle 2 includes, for example, a liquid introduction unit 11 that introduces a liquid, a gas introduction unit 12 that mixes a gas into the liquid introduced from the liquid introduction unit 11, as in the washing nozzle 10 illustrated in FIG. The gas-liquid mixed fluid introducing portion 13 for drawing the gas-liquid mixed fluid in which the gas is introduced into the supply liquid by forced introduction from the gas introducing portion 12 and the divergent nozzle portion 14 are configured.

  The divergent nozzle portion 14 is a nozzle that has a venturi tube shape after the gas-liquid mixed fluid introduction portion 13 has a sectional area that gradually decreases after the sectional area decreases in the flow direction. The venturi tube shape will be further described. A constricted portion with a reduced flow cross-sectional area is formed at the connecting portion between the gas-liquid mixed fluid introducing portion 13 and the divergent nozzle portion 14. When passing through the throat portion 15 having a cross-sectional area, the inner wall continuously expands in diameter. The space surrounded by the inner wall after the throat portion 15 has a substantially conical shape, and the space (substantially conical space) surrounded by the inner wall of the divergent nozzle portion 14 forms the microbubble generating portion 16. is doing. In the illustrated example, the throttle portion of the divergent nozzle portion 14 is formed on a linear inclined surface, but the sectional view shape may be formed on an R surface.

  Further, the divergent nozzle part 14 has a configuration having an injection port 17 for injecting a gas-liquid mixed fluid communicating with the microbubble generating part 16 at the tip. Here, the micro-bubble generating unit 16 (substantially conical space) may have an expansion angle θ larger than 0 degree and 40 degrees or less, and preferably 20 degrees or less. The angle θ shown in FIG. 2 is 6 degrees.

  When this divergence angle θ is large, flow separation occurs in the vicinity of the injection port 17 and resistance to the flow increases. Therefore, it is necessary to increase the pressure at the inlet of the nozzle, and it is necessary to use extra power accordingly. By narrowing the spread angle θ, it is possible to provide a nozzle that is excellent in energy saving. In the illustrated embodiment, the inner wall of the space surrounded by the inner wall of the divergent nozzle portion 14 is linear in the cross-sectional view (the space is conical). For example, it is formed on a gently curved surface in the cross-sectional view. May be.

  The components of the cleaning nozzle 10 can be made of metal such as stainless steel, titanium, gunmetal, brass, acrylic resin, fluorine resin, resin such as PVC, polypropylene, polyethylene, processable glass, etc., but are limited to these materials However, it can be made by adopting an appropriate material among materials having weather resistance to the use environment of the cleaning nozzle and strength capable of withstanding the pressure of the supply liquid or the like.

  The liquid supply means 3 is for supplying a liquid as a cleaning liquid to the cleaning nozzle 2, and any liquid supply means 3 may be used as long as it can supply the liquid at a predetermined flow rate.

  The liquid supplied by the liquid supply means 3 is drawn into the cleaning nozzle 10 from the liquid introduction unit 11 and is ejected from the cleaning nozzle 2 as a gas-liquid mixed fluid to be used for cleaning the surface to be cleaned. Any tap water, pure water, ultrapure water, organic solvent, chemical solution, or the like having a cleaning effect can be used without particular limitation. The temperature of the liquid is not particularly limited, but is often used around room temperature of about 20 to 25 ° C., and higher temperature can enhance the cleaning effect.

  At this time, since microbubbles can be stably present, a bubble coalescence inhibitor may be added to the liquid. Microbubbles are easily combined into a plurality of microbubbles, or a plurality of bubbles are combined to form a foam first, and then combined into a large diameter bubble. This is because this is effective in preventing this.

  As the coalescence preventive agent used here, it is known as an agent for preventing coalescence of bubbles such as alcohols such as isopropyl alcohol (IPA), pentanol and octanol, salts such as salt and potassium chloride, and other surfactants. These materials can be used. The amount of the bubble coalescence inhibitor added is preferably such that the solution concentration is in the range of 50 to 40,000 ppm.

  The gas supply means 4 can introduce gas into the gas introduction part 12 of the cleaning nozzle 2 in order to mix the gas into the liquid introduced from the liquid introduction part 11, and includes a compressor and the like. The gas is forcibly mixed in.

  In this embodiment, air is introduced. However, a liquid storage tank may be provided, and a gas other than air stored in the liquid storage tank may be forcibly introduced into the liquid. Examples of the gas introduced at this time include nitrogen, oxygen, carbon dioxide gas, hydrogen, argon, and ozone.

  The liquid supply means 3 and the gas supply means 4 are connected to a liquid storage means for storing the supplied liquid and a gas storage means for storing the supplied gas, respectively, and the liquid and gas stored when cleaning is performed. Can be supplied to the cleaning nozzle 2. The liquid storage means and the gas storage means are, for example, containers made of metal, resin, etc., and the materials thereof are particularly limited as long as the liquid or gas can be stably stored. It can be used without.

  Further, the gas storage means is not particularly required when air is introduced as a gas, and the gas supply means 4 can compress the air existing around it and send it to the cleaning nozzle. That's fine.

  Next, the cleaning method of the present invention will be described using a cleaning apparatus using the cleaning nozzle shown in FIG. 2 as an example.

  The cleaning method of the present invention ejects a liquid containing fine bubbles from the cleaning nozzle 2 to the object to be cleaned, and removes contaminants present on the cleaning surface of the object to be cleaned, thereby efficiently removing the contaminants. For this purpose, the liquid containing microbubbles is made to collide with the cleaning surface at a predetermined pressure or higher. Therefore, first, a liquid introduction process is performed in which the liquid stored in the liquid storage means is introduced into the cleaning nozzle 2 by the liquid supply means 3, and then gas is supplied to the liquid introduced into the cleaning nozzle 2 by the gas supply means 4. The mixed gas introduction step is performed.

  Here, in the case where the cleaning nozzle 10 is used, the liquid introduction step is to introduce a liquid serving as a cleaning liquid from the liquid introduction unit 11 into the cleaning nozzle. This liquid passes through the inside of the cleaning nozzle and is injected from the injection unit of the cleaning nozzle onto the object to be cleaned, and is used for cleaning the object to be cleaned.

  At this time, the supply pressure of the liquid introduced from the liquid introduction unit 11 to the cleaning nozzle is affected by the shape of the cleaning nozzle and the like, but the injection pressure of the liquid onto the object to be cleaned, that is, a desired cleaning power is obtained. Can be appropriately adjusted and used.

  For example, when the distance between the cleaning nozzle 20 and the object to be cleaned is 1 to 5 cm, the liquid supply pressure is 0.1 to 0.5 MPa in order to efficiently remove contaminants from the surface to be cleaned. It is preferable to carry out at 0.2 to 0.4 MPa.

  The gas introduction step performed next introduces gas from the gas introduction unit 12 in order to mix the gas into the liquid introduced into the cleaning nozzle. This gas is, for example, a gas supply means such as a compressor. 4 causes gas to be mixed into the liquid.

  When the gas is introduced by a compressor, the gas can be forcibly introduced. Therefore, the gas-liquid ratio can be arbitrarily set, and the amount of introduced gas can be increased by pressure, which is preferable.

  At this time, the ratio (void ratio) of the gas in the liquid can be 10 to 40%, preferably 10 to 30%, and particularly preferably 20% or more. For example, in FIG. 2, when the cleaning nozzle 10 having a diameter of the throat portion 15 of 3 mm and θ of 6 ° is used, and the pressure applied to the supply liquid is 0.3 MPa, the supply amount of the liquid is 9. It is preferable that 0 mL / min and the gas supply amount be 1.8 NL / min. Thereby, a void rate can be made into 20% or more, and a high cleaning effect can be acquired.

  Then, the microbubble generation process generates a pressure difference in the flow direction of the gas-liquid mixed fluid so that the supply liquid into which the gas has been introduced passes through a narrower flow path and a wider flow path. In this way, a large number of microbubbles are generated in the liquid mixed with gas. First, the gas-liquid mixed fluid obtained by the liquid supply means and the gas supply means passes through the gas-liquid mixed fluid introduction portion 13 and then passes through the throat portion 15 from the throttle portion that narrows the flow cross-sectional area in the cleaning nozzle 10. Then, it passes through the divergent part where the flow cross-sectional area increases in the flow direction of the gas-liquid mixed fluid. At this time, the pressure in the throat portion 15 is reduced by Bernoulli's theorem, and the pressure increases when entering the divergent portion, and the gas mixed in the liquid is sheared by the turbulence generated at this time, and a large number of Microbubbles are generated. Here, the divergent portion where the pressure immediately after passing through the throat portion increases serves as a place for generating microbubbles as the microbubble generating portion.

  The microbubbles generated here generate, for example, many bubbles having a diameter of 50 to 500 μm, preferably 50 to 200 μm.

  Next, the injection process injects the gas-liquid mixed fluid containing a large number of microbubbles generated in the microbubble generation process onto the object to be cleaned, and removes contaminants present on the cleaning surface of the object to be cleaned from the cleaning surface. To do.

  At this time, for example, it is known that a liquid containing microbubbles has a higher cleaning effect compared to cleaning with only a liquid, but this may occur when a liquid containing microbubbles collides with an object to be cleaned. This is thought to be because of the following effects.

  That is, the contaminants are removed from the cleaning surface by impact due to the flow of the liquid as in the case of the liquid alone, and also when the microbubbles 51 collide with the cleaning surface of the cleaning object 50 as shown in FIG. The microbubbles 51 are deformed as shown in FIG. 3 due to the influence of the above, and the liquid existing between the microbubbles 51 and the cleaning target object 50 immediately before the microbubbles 51 and the cleaning target object 50 collide with each other. It is considered that the collision accelerates in the horizontal direction with the cleaning surface and is pushed out, and the removal of the contaminant 52 is promoted by the flow (side jet) of the pushed liquid at this time.

  Further, the injection direction of the liquid injected from the cleaning nozzle 10 is not particularly limited as long as it is injected onto the cleaning surface of the object to be cleaned. However, the liquid is injected in a direction perpendicular to the cleaning surface. This is preferable in that the pressure when the liquid containing microbubbles collides with the cleaning surface is maximized and the cleaning effect is enhanced.

  As in this embodiment, by increasing the void ratio, the amount of liquid used as a cleaning liquid can be reduced compared to cleaning with water alone or cleaning with conventional air bubbles. The washing operation can be performed at a low cost. Nevertheless, a cleaning effect equal to or higher than that can be obtained.

  Further, when the void ratio becomes high in this way, even if the supply pressure of the liquid by the liquid supply means is lower than that of water-only cleaning or conventional air-containing cleaning, the cleaning is equivalent or better. An effect can be obtained.

(Second Embodiment)
This second embodiment is based on a cleaning apparatus having the same configuration as that of the first embodiment except that the cleaning nozzle 20 shown in FIG. 4 is used as the cleaning nozzle and the gas supply means 4 is not provided. is there. The cleaning nozzle 20 is provided with a suction-type gas introduction port for performing gas introduction by self-supply in the cleaning nozzle 10, and other than taking in gas from the suction-type gas introduction port 26 without providing gas supply means individually. The configuration is the same as that of the cleaning nozzle 10 of FIG.

  That is, the cleaning nozzle 20 includes a liquid introduction part 21 for introducing a liquid and a divergent nozzle part 22. The divergent nozzle portion 22 is a nozzle that gradually increases after the cross-sectional area decreases in the flow direction in the liquid introduction portion 21, and has a Venturi tube shape. The connecting part between the liquid introducing part 21 and the divergent nozzle part 22 is formed with a throttle part with a reduced flow cross-sectional area, and after passing through the throat part 23 with a constant cross-sectional area, the inner wall becomes The space continuously expanding and surrounded by the inner wall after the throat portion 23 has a substantially conical shape. A space (substantially conical space) surrounded by the inner wall of the divergent nozzle portion 22 forms a microbubble generator 24. In the illustrated example, the throttle portion of the divergent nozzle portion 22 is formed on a linear inclined surface, but the sectional view shape may be formed on an R surface. Further, the divergent nozzle part 22 has a tip part constituting an injection port 25 for injecting a gas-liquid mixed fluid that communicates with the microbubble generation part 24.

  Further, the throat portion 23 is provided with a suction type gas introduction port 26 for mixing gas into the liquid in a self-sufficient manner. This is because the liquid introduced by the liquid introduction portion 21 increases the flow velocity at the throat portion 23, so that the venturi effect is achieved. As a result, the pressure is reduced, and the surrounding gas is naturally sucked into the reduced liquid flow. By adopting a configuration in which gas is supplied in a self-sufficient manner, a device such as a compressor becomes unnecessary, and the gas is supplied at a constant rate, that is, the suction air amount (void ratio) with respect to the unit water flow rate at a constant rate in the supply liquid. It becomes a simple structure which can be taken in. Therefore, it is possible to configure a cleaning apparatus that is simple in operation and low in cost.

  At this time, the void ratio depends on the shape of the cleaning nozzle 20, particularly the shape of the throat portion 23 and the suction type gas inlet 26, and the flow rate of the liquid when used, but can be 10 to 30%. Further, it may be 20% or more which is preferable for cleaning.

  In this embodiment, since the gas introduction is performed in a self-contained manner, it is not necessary to provide gas introduction means separately, and the energy associated with the gas introduction can be saved and reduced as compared with the case where the cleaning nozzle of the first embodiment is used. Cleaning operation can be performed at a low cost.

(Third embodiment)
This third embodiment differs from the second embodiment only in that a plurality of suction type gas inlets are provided as cleaning nozzles, and the other configuration is the same as that of the second embodiment. It is what has. Hereinafter, the cleaning nozzle as a difference will be described. FIG. 5 is a cross-sectional view of the divergent nozzle portion perpendicular to the flow direction of the gas-liquid mixed fluid, and illustrates a portion provided with a suction type gas inlet.

  As shown in FIG. 5, the cleaning nozzle used in this embodiment has a suction-type gas inlet, and has a plurality of the suction-type gas inlets. 5, FIG. 5 (a) shows two suction-type gas introduction ports 26A, FIG. 5 (b) shows three suction-type gas introduction ports 26B, and FIG. 5 (c) shows four suction-type gas introduction ports 26C. Although an example has been given, it is also possible to provide more suction type gas inlets.

  The cleaning nozzle having the suction-type gas inlet as in the second embodiment is excellent as a cleaning nozzle because it is not necessary to separately provide a means for supplying gas and the gas introduction efficiency can be maintained high. However, the injection center of the gas-liquid mixed fluid sometimes deviates from the extension of the axis of the cleaning nozzle. The axis of the cleaning nozzle is the axis of the throat part and the axis of the divergent part (the central axis of the substantially conical shape). The cause of the gas-liquid mixed liquid to be injected is not clear, but from the suction type gas inlet It is considered that the introduced gas tends to be present in the divergent part in a side face where the suction type gas inlet is provided, and the gas-liquid mixed fluid can be easily ejected in the opposite direction.

  Therefore, in this embodiment, a plurality of suction-type inlets are provided in order to eliminate such deviation (diffusion) at the time of injection of the gas-liquid mixed fluid, but at this time, the suction-type gas inlets are The gas supply locations in the throat section are preferably arranged at equal intervals. By arranging them at regular intervals in this way, the injection position of the liquid containing microbubbles can be adjusted so that the center of injection is near the extension of the axis of the cleaning nozzle, and the cleaning surface of the object to be cleaned In this case, the gas-liquid mixed fluid can be ejected to a desired position. At this time, it is preferable that each suction type gas introduction port introduces the same amount of gas.

  The cleaning nozzle in the embodiment described above has a substantially conical shape at the divergent portion in the microbubble generating unit, but this has a substantially polygonal pyramid shape such as a triangular pyramid, a quadrangular pyramid, a pentagonal pyramid, A substantially triangular prism shape may be used. In addition to a single cleaning nozzle, there may be a cleaning device configured to increase the cleaning efficiency by aligning a plurality of nozzles, and a plurality of injection ports through which gas-liquid mixed fluid can be injected are slit-shaped. It can also be provided.

(Example 1)
The following experiment was performed using a cleaning apparatus configured using the cleaning nozzle shown in FIG. 4, that is, a cleaning apparatus including a liquid storage unit, a liquid supply unit, and a cleaning nozzle. The liquid stored in the liquid storage means of the cleaning device used here is filtered water.

  In the liquid storage means of the cleaning device, a cleaning liquid in which 1000 ppm of isopropyl alcohol is dissolved in filtered water obtained by filtering tap water through a filter having a pore diameter of 1 μm is stored, and the cleaning liquid can be supplied to the cleaning nozzle by a pump. A cleaning nozzle having a diameter of 1.0 mm at the throat portion was installed so as to inject the cleaning liquid. In addition, as a cleaning object, a cover glass having a width of 24 mm × a length of 30 mm in which white petrolatum is uniformly applied to the surface to a thickness of about 0.15 mm is prepared, and this is a position 3 cm away from the injection port of the cleaning nozzle Placed horizontally.

  With respect to the cleaning surface of this glass substrate, filtered water having a liquid temperature of 24 ° C. stored in the liquid storage means is supplied to the cleaning nozzle by a pump at a flow rate of 700 mL / min and a supply pressure of 0.17 MPa. A cleaning liquid containing microbubbles was ejected for 10 seconds.

  At this time, the amount of air sucked from the suction-type gas introduction part was 191 mL / min, and the void ratio of the cleaning liquid was 21% by volume.

By this washing operation, it was confirmed by visual observation that white petrolatum applied to the washing surface was sufficiently removed, and the removal area of white petrolatum in the cover glass after the washing operation was 3.52 mm ² .

  Moreover, the white petrolatum washing operation when the amount of air suck | inhaled here was adjusted and the void ratio was changed to 11-29% was performed similarly, and the removal area of white petrolatum was calculated | required. The results are shown in Table 1.

(Comparative Example 1)
Using the cleaning device having the same configuration as in Example 1, the suction type gas inlet of the cleaning nozzle was closed, and the white petrolatum was cleaned in the same manner as in Example 1 when the cleaning liquid had a void fraction of 0%. The removal area of white petrolatum was determined. The results are also shown in Table 1.

この結果から、ボイド率が１０％程度となると汚染物質の固体表面からの除去効果が有効に得られ、２０％以上になると特に好ましい除去効果が得られることがわかった。

From this result, it was found that when the void ratio was about 10%, the effect of removing contaminants from the solid surface was effectively obtained, and when it was 20% or more, a particularly preferable removal effect was obtained.

(Comparative Example 2)
The test was performed in the same manner as in Example 1 except that the suction type gas inlet of the cleaning nozzle was closed in the cleaning apparatus having the same configuration as in Example 1 so that the void ratio of the cleaning liquid was 0%. .

  At this time, the flow rate of the cleaning liquid supplied from the liquid storage means to the cleaning nozzle by the pump is 900 mL / min, the supply pressure is 0.28 MPa, and the water flow rate of Example 1 is 700 mL / min + air flow rate of 191 mL / min. Thus, the test was conducted with the same total amount of fluid.

By this washing operation, it was confirmed by visual observation that white petrolatum applied to the washing surface was not removed, and the removal area of white petrolatum in the cover glass after the washing operation was 0 mm ² .

(Example 2)
A cleaning apparatus having the same configuration as in Example 1 was used, and the same cleaning operation as in Example 1 was performed except that isopropyl alcohol was not dissolved and filtered water obtained by filtering tap water through a filter having a pore size of 1 μm was used as the cleaning liquid. The removal area of white petrolatum was determined. Here, the void ratio is 11% and 21%, and the results are shown in Table 2.

It is the schematic which showed the structure of the washing | cleaning apparatus which concerns on this invention. It is the schematic sectional side view which showed the structural example of the washing nozzle which concerns on this invention. It is a schematic diagram explaining the washing | cleaning mechanism by the micro bubble at the time of washing | cleaning. It is a schematic sectional side view of the other washing nozzle which concerns on this invention. It is sectional drawing of the divergent nozzle part perpendicular | vertical with respect to the flow direction of a gas-liquid mixed fluid.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cleaning apparatus, 2 ... Cleaning nozzle, 3 ... Liquid supply means, 4 ... Gas supply means, 10 ... Cleaning nozzle, 11 ... Liquid introduction part, 12 ... Gas introduction part, 13 ... Gas-liquid mixed fluid introduction part, 14 ... Suehiro nozzle part, 15 ... Throat part, 16 ... Microbubble generation part, 17 ... Injection port, 20 ... Cleaning nozzle, 21 ... Liquid introduction part, 22 ... Swelling nozzle part, 23 ... Throat part, 24 ... Microbubble generation part, 25 ... Injection port, 26 ... Suction type gas inlet, 50 ... Object to be cleaned, 51 ... Microbubble, 52 ... Contaminant

Claims (12)

The flow introduction area gradually increases in the flow direction of the liquid introduction section for introducing the liquid, the gas introduction section for mixing the gas into the liquid introduced from the liquid introduction section, the throttle section for narrowing the flow cross section, and the gas-liquid mixed fluid. And a divergent nozzle part that generates a large number of microbubbles from the gas introduced from the gas introduction part, and a gas-liquid mixed fluid containing the generated many microbubbles to the object to be cleaned. A cleaning nozzle having an injection port;
A liquid supply means for supplying the liquid used for cleaning to the liquid introducing portion of the cleaning nozzle;
A gas supply means for introducing gas into the gas introduction portion of the cleaning nozzle in order to mix gas into the liquid introduced from the liquid introduction portion;
A cleaning apparatus comprising: A liquid introduction part for introducing a liquid; a self-contained gas introduction part for mixing gas into the liquid introduced from the liquid introduction part; a throttle part for narrowing a flow cross-sectional area; and a flow cross-sectional area in the flow direction of the gas-liquid mixed fluid And a divergent nozzle part that generates a large number of microbubbles from the gas introduced from the gas introduction part, and a gas-liquid mixed fluid containing the generated many microbubbles to be cleaned. A cleaning nozzle having an injection port for injecting into
A liquid supply means for supplying the liquid used for cleaning to the liquid introducing portion of the cleaning nozzle;
A cleaning apparatus comprising:   3. The cleaning apparatus according to claim 2, wherein a plurality of the self-contained gas introduction portions in the cleaning nozzle are provided at equal intervals in a vertical cross section with respect to a flow direction of the gas-liquid mixed fluid.   The cleaning device according to any one of claims 1 to 3, wherein the divergent portion has a substantially conical shape and expands in the flow direction of the gas-liquid mixed fluid.   The cleaning apparatus according to any one of claims 1 to 4, wherein an opening angle of the divergent portion is 20 degrees or less.   A liquid introduction step for introducing a liquid, a gas introduction step for mixing gas into the liquid introduced from the liquid introduction step, and a flow of gas-liquid mixed fluid formed after the constricted portion that narrows the flow cross-sectional area in the flow direction A gas-liquid mixed fluid is caused to pass through the divergent part having a gradually increasing area to generate a large number of microbubbles from the gas introduced from the gas introduction part, and a gas containing a large number of generated microbubbles. An injection step of injecting the liquid mixture fluid onto the object to be cleaned.   The cleaning method according to claim 6, wherein an opening angle of the divergent portion is 20 degrees or less.   The cleaning method according to claim 6 or 7, wherein the gas introduction step is self-contained.   The cleaning method according to any one of claims 6 to 8, wherein the gas introduction step is performed at a plurality of positions at equal intervals in a vertical cross section in the flow direction of the gas-liquid mixed fluid.   The cleaning method according to any one of claims 6 to 9, wherein a supply pressure of the liquid in the liquid introduction step is 0.1 to 0.5 MPa.   The cleaning method according to any one of claims 6 to 10, wherein the void ratio of the gas-liquid mixed fluid containing the microbubbles generated in the microbubble generating step is 10 to 30%.   The cleaning method according to any one of claims 6 to 11, wherein microbubbles are ejected while suppressing coalescence of the generated microbubbles by adding a bubble coalescence inhibitor to the liquid.

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