JPH1094766A - Washing device using high density liquefied gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable almost complete reduction of expense items, attainment of effective washing by revelation of strong washing force and dissolving of resticking by this, and washing of fouling components of hardly soluble inorganic compounds, polar materials and the like even in the case of solvent having critical temperature near room temperature. SOLUTION: In a recirculation system in which high density liquefied gas is closed, plural preaching nozzles 3, low pressure chambers 10 for expanding compressed liquid 5, and a forcibly agitating device of soundwave generators 12 and an agitating blade 11 are arranged in a pressure washer 1 to attain strong washing accompanied by bubbling. A pressure recovery vessel 14 for receiving washing treated liquid is positioned below the washer 1, and a drain cylinder 16 which is freely attachably and detachably assembled therewith is provided, hung therefrom, and also a temperature controller 15 is incorporated in the vessel 14, and contaminated liquid of preaching is immediately received from the pressure washing chamber by a chamber branching function. Furthermore, the washer 1 is made in vapor phase communication with a high density liquefied gas feeding cylinder 18 above, and solvent separation and conveyance is performed by vaporization by the temperature controller 15, and also contaminant settled and concentrated liquid is discharged through a drain cylinder 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus using a high-density liquefied gas which achieves high cleaning efficiency without requiring any high-pressure generator such as an expensive compressor or pump.

[0002]

2. Description of the Related Art When an object to be cleaned such as a semiconductor is accommodated in a pressure-resistant cleaning device, a supercritical fluid is injected into the pressure-resistant cleaning device by a supercritical supply means, and the supercritical fluid is brought into contact with the object to be cleaned. Water and organic substances adhering to the cleaning object dissolve in the supercritical fluid and move to the supercritical fluid. When the supercritical fluid in which the water or the organic substance is dissolved is removed from the pressure-resistant cleaning device by an appropriate means, an object to be cleaned which is precisely cleaned later can be obtained. Since the water has been removed, it is not necessary to perform a troublesome dry finish in a conventional so-called wet cleaning method.

When the supercritical fluid in which the contaminants are dissolved is depressurized in a separation tank, the dissolved contaminants are precipitated, and the supercritical fluid that has released the contaminants can be reused. This is because the pressure and temperature conditions are P> P _c (critical pressure) and T> T _c (critical temperature) near the critical point as seen in the phase diagram of the pure substance and the graph of the supercritical fluid in FIG. (1) A large change in density can be obtained by a slight change in pressure.
In general, since the solubility of a substance is proportional to the density, a large difference in solubility can be obtained only by a change in pressure. (2) The density of a supercritical fluid is similar to that of a liquid, but has low viscosity and high diffusivity. Therefore, it is more advantageous in terms of mass transfer. This is the latest cleaning technology that has come to be used for cleaning semiconductor substrates and the like that make good use of the technology.

[0004] The principle is that firstly, the low viscosity of the supercritical fluid indicates that it is easy to penetrate into narrow parts,
The high density of the fluid means that the contaminants attached to and impregnated on the substrate have high solubility in organic fluids. Secondly, the above-mentioned cleaning action is provided by the supercritical fluid containing the contaminants. However, by reducing the density, the dissolving action is reduced, and accordingly, the above-mentioned components are deposited in a liquid or solid state. Therefore, it utilizes the fact that these components can be recovered in a decompressed separation tank. A closed recirculation system is constructed in which the supercritical fluid purified by depositing the contaminants is recycled to the pressure washer through the storage means. The gases used are carbon dioxide,
Nitrogen oxide, ethane, hexane, propane and the like are used. In particular, carbon dioxide is nonflammable, harmless, inexpensive, and has a critical temperature of 31.1 ° C. and a critical pressure of 72.8 atm. It is preferably used because it is easy to handle.

[0005] Generally, a high-pressure generator such as a compressor or a pump is used as a fluid conveying means in the recirculation system described above. Since these devices require high pressure resistance, the cleaning device becomes extremely expensive. Relying solely on the dissolving power, if not effective, may require forced agitation or the application of ultrasonic energy to cavitation, i.e., the formation of bubbles and subsequent collapse. You. In addition, effective entrainers for various hardly soluble dirt components have been elucidated.

[0006] The characteristics of the supercritical fluid as described above also include a subcritical fluid. A subcritical fluid is a fluid in a region just before a critical point in a pressure-temperature state diagram, in which a compressed liquid and a compressed gas coexist. Fluids in this region are distinguished from supercritical fluids. Subcritical or, in a broad sense, those present in the supercritical region near the critical point are called high-density liquefied gases.

The use of a high-density liquefied gas near the critical point as a solvent relaxes the strict pressure requirement of the supercritical fluid,
Japanese Patent Application Laid-Open No. 171527/1995 proposes a relatively simple cleaning means for reducing the cost items. Japanese Patent Laid-Open No. 7
The feature of the '171527 is that a temperature control means is provided in the cleaning device, and that cavitation using ultrasonic energy is used.

That is, in the cleaning device, liquefaction is promoted by temperature control means to cause cavitation by ultrasonic energy, thereby compensating for the disadvantage of abandoning the advantages of cleaning in a supercritical state.

[0009]

The above-mentioned conventional cleaning means using high-density liquefied gas has the following difficulties. (1) A means for applying a conveying pressure by a compressor to a storage means is used for a conveying power of the high-density liquefied gas in a closed recirculation system for separating dirt components and a solvent for a high-density liquefied gas. Remains. (2) The lack of detergency is compensated for by cavitation using ultrasonic waves. However, depending on the degree of contamination of the object to be cleaned, such forced stirring may not be sufficient, and such situations cannot be dealt with. The cleaning action is performed by immersing the object to be cleaned in a liquid.However, there are many solid contaminants in the liquid, which are suspended, and this reattaches to the object to be cleaned. Become. In the case where such re-adhesion is not allowed, there is an inconvenience that a step of washing again with a washing fluid must be added. (3) The solvent has a critical temperature near room temperature (such as CO ₂ )
When a high-density liquefied gas is used, there is no effect at all for cleaning hardly soluble dirt components, particularly dirt components of inorganic compounds and polar substances, but there is no solution for cleaning such hardly soluble dirt components.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the almost perfect reduction of the cost items, the development of a strong cleaning power, and the efficient cleaning by eliminating reattachment. To provide a cleaning apparatus using a high-density liquefied gas that has achieved, for example, a solvent having a critical temperature near room temperature, enabling the cleaning of contaminant components such as hardly soluble inorganic compounds and polar substances. Things.

[0011]

In order to achieve the above object, a cleaning apparatus using a high-density liquefied gas according to the present invention comprises: Pressure washing with a plurality of nozzles for directly spraying the compressed liquid into the container and a low-pressure chamber connected to the upper part of the vessel, and a stirrer comprising a rotor at the bottom and a sound wave generator directed to the rotor at the side of the vessel. A pressure recovery container as a compartment of a pressure-resistant washer for receiving a cleaning liquid after a cleaning process, wherein a drain cylinder is provided with a temperature control means installed at a lower position than the pressure-resistant washer and detachably assembled. And a high-density liquefied gas supply cylinder as storage means for providing a temperature control means installed at a position higher than the pressure-resistant washer and communicating between the upper part of the pressure-resistant container and the pressure-resistant recovery vessel to receive the upper gas. When A closed recirculation system is configured from a connected entrainer vessel in the middle of the liquid feed pipe between the high-density liquefied gas supply cylinder and the pressure-resistant washer. The upper gas is connected so that it can communicate with the upper gas.

It is preferable that a plurality of recycle systems including a pressure-resistant recovery vessel and a high-density liquefied gas supply cylinder are provided for the pressure-resistant washer in a switchable manner. In the above apparatus, it is preferable that the solvent material cylinder is installed at a position higher than the pressure-resistant washer and that the apparatus is provided with a temperature adjusting means, and that the upper gas and the pressure-resistant washer are communicated so that the upper gases can communicate with each other. .

[0013]

The present invention makes full use of the advantages of high-density liquefied gas that exists in both the subcritical and supercritical regions near the critical point. In other words, the energy required for heating and vaporization and cooling and liquefaction is smaller in the vicinity of the critical point, but the transport of the solvent is carried out by vaporization, vapor pressure difference in the liquefied state, and gravity drop transport with the level difference set against the vapor pressure difference. As a result, there is no need for an expensive high-pressure generator, and reduction in cost items can be expected.

The pressure-resistant washer having a pressure-recovery device in the lower part of the compartment is in communication with the pressure-recovery device, and immediately removes dirt that may be re-adhered, such as lumps or the like, which are dropped by pre-washing by spraying a plurality of nozzles. The main washing, which is performed under solvent filling in the vessel which is drained and then performed, may be advantageous in that it does not contain any dirt generated in the prewash. As a result, the chance of reattachment of lump components such as lump which may possibly reattach is completely lost, and reattachment is prevented. In addition, since it can be repeated repeatedly, perfect washing can be expected.

In addition, since a low-pressure chamber is provided and can be expanded when the solvent is filled, bubbling due to expansion, which is a phenomenon unique to the vicinity of the critical point, easily occurs, and cavitation caused by this, so-called stirring power, is generated in the entire solvent. You can enjoy.
In the case of dirt components that are hardly soluble and cannot be cleaned with only a high-density liquefied gas alone, it has been discovered that the addition of a surfactant according to the target dissolves the dirt components in a so-called micellization phenomenon. The cleaning of the inorganic compound and the polar substance can also be achieved by utilizing the above. Further, the micelle-formed dirt component is prevented from re-adhering due to its barrier effect, and the detergency is improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. The pressure-resistant cleaning device 1 supports a cleaning basket 2 for storing an object to be cleaned in the air immediately below a plurality of (necessary for effective cleaning) nozzles 3. The nozzle 3 is preferably capable of swinging. Pre-cleaning is performed by projecting from the nozzle 3 onto the object to be cleaned in the cleaning basket 4 by a jet stream. The impact energy of the jet jet is effective in forcibly separating contaminants.

In the illustrated example, a solvent raw material cylinder 6 filled with a high-density liquefied gas for feeding a compressed liquid 5 through the high-pressure pipe 4 and the nozzle 3 to the pressure-resistant washer 1 is temperature-controllable in the illustrated example. The compressed liquid 5 is accommodated in a box 8 equipped with a vessel 7 and is installed at a position higher than the pressure-resistant washer 1 so that the compressed liquid 5 is fed under a level difference dropping action. The transfer is ensured by the vapor pressure difference at a higher temperature setting than the pressure-resistant washer 1, and is backed up by the gas-phase communication of the high-pressure pipe 9 communicating between the upper portions of both containers.)

A low-pressure chamber 10,... For expanding the space of the apparatus is provided connected to the upper part of the pressure-resistant cleaning apparatus 1. The low-pressure chamber 1
With 0, it is possible to cause bubbling of the filled compressed liquid 5 in the pressure-resistant washer 1 due to expansion. Also,
As shown in detail in FIG. 3c, a rotating blade 11 is provided on the bottom of the vessel 1 directly below the washing basket 2 and a sound wave generator 12 directed to the rotating blade 11 is arranged on the side wall of the vessel 1, and the ultrasonic energy and its projection are used. Cavitation with the rotating blades 11 and synergistic action of forced agitation enable more powerful agitation. Thus, the main cleaning of the object to be cleaned, which is performed by immersion in the filled compressed liquid 5, can be performed under intense stirring. The above-mentioned bubbling and cavitation are effective in destroying and killing bacteria and bacteria by the rapid decompression.

An entrainer container 13 is connected to the pipe 4 just before the nozzle 3. When the entrainer container 13 has a dirt component that is hardly soluble and cannot be washed with only the high-density liquefied gas alone, an lipophilic, hydrophilic, or amphiphilic surfactant is stored in advance depending on the dirt component, and the orifice action Thus, it is sucked into the compressed liquid 5 in the pipe 4. Since the surfactant dissolves the hardly soluble dirt component by a so-called micellization phenomenon, reattachment hardly occurs due to its barrier effect.

At a position lower than the pressure-resistant washer 1, a pressure-resistant recovery container 14 for receiving the cleaning liquid 5 'is arranged. Acceptance is made promptly by falling levels, vapor pressure differences, and gas phase communication. The container 14 has a built-in temperature controller 15 and a drain cylinder 16 detachably assembled from the bottom of the container.
Droop. Therefore, it is possible to remove the drain cylinder 16 containing a large amount of the dirt component, remove the drain cylinder 16 from the communication with the recirculation system, and empty the drain cylinder 16 at a predetermined place, and then remount the drain cylinder 16.
The pressure-resistant recovery container 14 serves as a compartment of the pressure-resistant cleaning device 1.
In other words, the cleaning liquid 5 'containing plenty of dirt (including lumps) that is communicated and dropped during the pre-cleaning described above is immediately received and does not stop in the pressure-resistant cleaning device 1 (FIG. 3).
a). Therefore, in the above-described main cleaning, which is performed by filling the compressed liquid 5 in the pressure-resistant cleaning device 1 that is cut off the communication, the cleaning is performed without including dirt in the pre-cleaning, and the cleaning efficiency can be improved (FIG. 3B). ). Thereby, the so-called redeposition is completely eliminated.

By repeating this cleaning, high cleaning efficiency is guaranteed. Thus, an excellent cleaning mechanism having a function of preventing redeposition is provided by the pressure-resistant cleaning device and the pressure-resistant recovery device 14. However, when a high-density liquefied gas alone contains a dirt component that is hardly soluble and cannot be completely cleaned, a surfactant is introduced according to the dirt component to improve the detergency and prevent re-adhesion by the so-called micelle phenomenon. Can be combined as desired with forced separation of the impact energy of the nozzle, cavitation by bubbling, and stirring by ultrasonic waves, thereby further improving the cleaning efficiency.

A pipe 17 for communicating with the gas phase is connected to the pressure-resistant washing vessel 1. The gas phase of the pressure recovery container 14 is further connected to the upper part of the high-density liquefied gas supply cylinder 18 as storage means of a closed recirculation system installed at a position higher than the pressure-resistant cleaning container 1 via a pipe 19, The solvent heated and vaporized by the temperature controller 15 of the recovery container 14 is transported to the upper cylinder 18 with a vapor pressure difference. On the other hand, since the gas phase has a low density and a low dissolving power, contaminants and entrainers having a high specific gravity are concentrated and precipitated in a lower liquid phase. This enrichment section is replaced with a drain cylinder 16
To separate the contaminated components by discharging to the outside of the system. That is, the separation and recovery mechanism including the pressure-resistant recovery container 14 and the high-density liquefied gas supply cylinder 18 achieves the removal of the dirt component and the recovery and transportation of the solvent without any high-pressure generator. This is the ultimate reduction in cost items.

The cylinder 18 has a built-in temperature controller 20, which cools and vaporizes the vaporized solvent. The pipe 21 below the cylinder 18 is the nozzle 3 of the pressure-resistant washer 1
Is connected to the pipe 4. A gas-phase communication pipe 22 is provided to complement the level difference drop conveyance. At this time, the fall is complemented by setting the temperature difference by heating the temperature controller 20. Here, there is provided a completely new recirculation system in which the washing solvent can be circulated only by the temperature control means.

[0024]

FIG. 2 shows an example in which a plurality of the above-mentioned recirculation systems (pressure-recovery container 14-high-density liquefied gas supply cylinder 18) are provided (two systems in the illustrated example). Can be increased. The three-way valve 23, 24
The pneumatic feeding is communicated and shut off by valves 26, 26 taken out of the three-way valve 25, respectively. Using this, an operation example in which the solvent is CO ₂ will be described below.

The entire apparatus of the present invention is an air-conditioning control device 2
7 and placed in a room 28 maintained at a temperature of 20 ° C., where humans can easily work. The cylinder 6 was controlled at 30 ° C. by the temperature controller 7. The pressure of the compressed liquid 5 in the cleaning device 1 dropped to about 20 ° C. due to the surfactant and the object to be cleaned. Pressure recovery container 1
In No. 4, the temperature was reheated to 30 ° C. by the temperature controller 15. Most of the supernatant was now vaporized. Since the vaporization time of one system was about 40 minutes in 4 gallons, it is reduced to 20 minutes in two systems.
The high temperature liquefied gas supply cylinder 18 has a temperature controller 20.
And cooled to 0 ° C. to fill the compressed liquid 5.

On the other hand, it takes about 10 minutes from the insertion of the object to be cleaned to the cleaning in the cleaning device 1, but by using two systems, a high operation rate with little waiting time for the next cleaning can be realized.

[0027]

Since the present invention is configured as described above, it has the following effects. (1) Not only in the closed recirculation system but also through the equipment that does not need to receive the level difference, the vapor pressure difference, and the pressure resistance of the gas phase communication, all of the transport of the solvent from the solvent material cylinder connected to it. This has been achieved, and the cost items have been significantly reduced. (2) The cleaning mechanism and separation / collection mechanism of the pressure-resistant washer, pressure-recovery device, high-density liquefied gas supply cylinder, etc. eliminated strong cleaning power, efficient removal of contaminants, and no high-pressure generator. Solvent recovery is provided, and an inexpensive and efficient cleaning device is provided. (3) In the case of a dirt component that cannot be washed because it is hardly soluble only with a high-density liquefied gas alone, the dirt component is dissolved by a so-called micellization phenomenon by adding a surfactant according to an object, so that further cleaning is performed. Efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a basic configuration of a device of the present invention.

FIG. 2 is an explanatory diagram of an example in which a plurality of recycling systems of the apparatus of the present invention are provided.

3A is a diagram illustrating a rough cleaning in a pressure-resistant cleaning device, FIG. 3B is a diagram illustrating a main cleaning, and FIG.

FIG. 4 is a phase diagram of a pure substance and a graph of a supercritical fluid and a subcritical fluid region.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure-resistant washing machine 2 Cleaning basket 3 Nozzle 4 High-pressure pipe 5 Compressed liquid 5 'Cleaning liquid 6 Solvent material cylinder 7 Temperature controller 8 Box 9 High-pressure pipe 10 Low-pressure chamber 11 Rotary blade 12 Sound generator 13 Entrainer container 14 Pressure-resistant recovery container 15 Temperature controller 16 Drain cylinder 17 Pipe 18 High-density liquefied gas supply cylinder 19 Pipe 20 Temperature controller 21 Pipe 22 Gas-phase communication pipe 23 Three-way valve valve 24 Three-way valve valve 25 Three-way valve valve 26 Valve 27 Air-conditioning controller 28 Room

Claims (6)

[Claims] 1. A washing basket for accommodating an object to be washed is supported in the interior of a container, and a plurality of nozzles for directly spraying a compressed liquid onto the object to be washed and a low-pressure chamber connected to an upper portion of the container are provided. A pressure washer provided with a stirrer comprising a wing and a sound wave generator directed to the rotary wing on the side wall of the vessel, and a drain cylinder provided with a temperature control means installed at a position lower than the pressure washer and detachably assembled. A pressure-resistant recovery container as a compartment of a pressure-resistant washer for receiving the cleaning liquid after the washing treatment, and a temperature control means installed at a higher position than the pressure-resistant washer, and receiving the upper gas of the pressure-resistant container. A high-density liquefied gas supply cylinder as a storage means for communicating between the upper part between the high-pressure liquefied gas supply cylinder and the pressure-recovery container, and an entrainer capacity connected in the middle of the liquid feed pipe between the high-density liquefied gas supply cylinder and the pressure-resistant washer A high-density liquefied gas, characterized in that a closed recirculation system is constituted from the vessel and the upper portion between each of the compressed liquid receivers is communicated so that the upper gases can communicate with each other. Use of washing equipment. 2. A cleaning apparatus using a high-density liquefied gas according to claim 1, wherein a plurality of recyclable systems comprising a pressure-resistant recovery vessel and a high-density liquefied gas supply cylinder are provided for the pressure-resistant cleaning device in a freely switchable manner. . 3. The method according to claim 1, wherein the solvent raw material cylinder is installed at a higher position than the pressure-resistant washer, the temperature-controlling means is provided, and the upper gas and the pressure-resistant washer are communicated so that upper gas can communicate with each other. A cleaning apparatus using the high-density liquefied gas according to 1 or 2. 4. A plurality of nozzles for supporting a washing basket for accommodating an object to be washed in the inside of a vessel and directly spraying a compressed liquid onto the article to be washed and a low-pressure chamber connected to an upper portion of the vessel, and rotating at a bottom of the vessel. After the cleaning process, a drain cylinder equipped with a temperature control means and detachably assembled is provided below the pressure-resistant washer provided with an agitator comprising a wing and a sound wave generator directed to the rotary wing on the side wall of the vessel. A cleaning mechanism with a re-adhesion prevention function with a pressure-resistant recovery container attached as a compartment for receiving the cleaning liquid. 5. A pressure recovery container provided with a temperature control means and a drain cylinder which is removably assembled, and a temperature control means installed at a position higher than the pressure-resistant washer to receive a gas above the pressure container. A separation and recovery mechanism that does not require a high-pressure generator for separating dirt components and recovering the solvent, which consists of a high-density liquefied gas supply cylinder that communicates between the upper part and the pressure recovery container. 6. When there is a dirt component that is hardly soluble and cannot be washed with only a high-density liquefied gas alone, an lipophilic, hydrophilic or amphiphilic surfactant is added to the solvent via an entrainer container according to the dirt component. The function of improving the detergency and preventing re-adhesion due to the so-called micellarization phenomenon is combined with the purpose together with forced separation of impact energy of the nozzle, cavitation by bubbling, and stirring by ultrasonic waves. A method for handling a cleaning apparatus using the high-density liquefied gas described above.