JPH06120196A - Method and apparatus for ultrasonically cleaning and drying - Google Patents

Abstract

PURPOSE:To eliminate replacement of solvent by supplying solvent in a cleaning tank to a distillation column, evaporating the solvent in the column, separately removing impurities stored in the solvent in the tank by distilling, and rinsing and drying an article by clean solvent vapor. CONSTITUTION:An article 2 is introduced to a point A of a cleaning and drying chamber 1, lowered to be dipped in a cleaning tank 6 of a point B, and cleaned by an ultrasonic wave to be oscillated from an ultrasonic oscillator 7 while being vertically shaped. 0.25l/min of cleaning solvent is sent from the tank 6 by a pump 11 to a distillation colunm 12 in which stainless steel gauze is filled to 100 mm in a vapor rinsing chamber 8, It is vapor cleaned and rinsed by solvent vapor of high purity heated to be evaporated in the column 12. Further, it is vapor-dried with the vapor. Contaminant components in the solvent are discharged as drain 13 from a bottom of the column 12. Thus, the solvent in the tank is always held clean.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly suitable for cleaning and drying stains attached to articles such as precision articles.
The present invention relates to an ultrasonic cleaning / drying method and a device therefor, which do not use a nonflammable solvent such as trichloroethane but use a flammable solvent for safe, rapid, and highly accurate cleaning and drying.

[0002]

2. Description of the Related Art Conventionally, electronic devices such as photomask glass, magnetic disks, printed circuit boards, silicon wafers, lenses, etc.
In the manufacturing process of precision parts such as optical parts and mechanical parts such as bearings, oils and fats attached to the parts, abrasives, fingerprints,
For cleaning to remove dirt such as dust, use a nonflammable solvent such as CFC 113 and trichloroethane.
Generally, a method including ultrasonic immersion vertical swing cleaning, cooling shower cleaning, steam cleaning and steam drying is performed. Further, in some cases, a method of using a flammable solvent such as alcohol, turpentine oil, or kerosene using the cleaning / drying device according to the above process is used. Methods have been taken to prevent fire and explosion hazards by keeping it low or reducing the oxygen gas concentration.

[0003]

However, among the above-mentioned conventional methods, in the method using a nonflammable solvent, which is generally widely used, particularly in the case of Freon 113 and trichloroethane, ozone in the atmosphere surrounding the earth is used. Since the layers are destroyed and the amount of transmitted UV rays increases, which damages living things on earth, there is an urgent need to switch to an alternative solvent.

On the other hand, in a cleaning method using a flammable solvent (hereinafter referred to as a solvent), for example, as shown in the cleaning / drying apparatus of FIG. The dirt adhering to is removed, but at this time, impurities such as fats and oils are accumulated in the solvent by repeating washing. However, since this oil and fat is dissolved in the solvent, it cannot be separated by a filter or the like. If the amount of fats and oils dissolved in the solvent is large, it cannot be sufficiently washed even if steam rinsing is performed in a subsequent step, and stains remain on the surface of the article after drying. Therefore, it is necessary to replace the solvent in the cleaning tank before it becomes very dirty. As described above, the conventional solvent cleaning method has a problem in that a large amount of solvent is required and that the solvent is recycled or incinerated at high cost.

In the steam rinsing chamber 8 of the washing / drying apparatus, the solvent is evaporated by the evaporator 24 to rinse and dry the article, and the cleaned solvent is sprayed onto the article. In addition, when there is a component that causes azeotropy with the flammable solvent, there is a problem that only the flammable solvent cannot be separated.

[0006]

The inventors of the present invention have arrived at the present invention as a result of various studies to solve the above-mentioned conventional problems. That is, according to the present invention,
In an ultrasonic cleaning and drying method, which comprises ultrasonically cleaning an article with a flammable solvent contained in a cleaning tank, and then rinsing and drying with vapor of the solvent, supplying the solvent in the cleaning tank to a distillation column, Ultrasonic waves characterized by evaporating the solvent in the distillation column and separating and removing impurities accumulated in the solvent in the washing tank by distillation, and rinsing and drying the article with clean solvent vapor. A washing and drying method is provided.

Further, according to the present invention, a cleaning tank which accommodates a combustible solvent and is additionally provided with an ultrasonic cleaning device for ultrasonically cleaning an article, and a cleaning tank which is provided above the cleaning tank to clean the article A vapor rinse chamber for rinsing and drying with solvent vapor, a solvent shower chamber provided at the top of the vapor rinse chamber and having a nozzle for showering a condensate of clean flammable solvent vapor on the article, and a clean room for the vapor rinse chamber. A distillation column for supplying a flammable solvent vapor, in which the solvent in the cleaning tank is taken out and evaporated, and impurities accumulated in the solvent in the cleaning tank are separated and removed by distillation to obtain a clean solvent vapor. An ultrasonic cleaning / drying apparatus comprising a tower and an aeration drying chamber for drying a solvent liquid component attached to an article by a clean dry gas.

Furthermore, according to the present invention, a cleaning tank containing a combustible solvent and additionally provided with an ultrasonic cleaning device for ultrasonically cleaning an article, and a cleaning tank provided above the cleaning tank to clean the article Rinse and dry with solvent vapor,
A vapor rinsing / solvent shower chamber having a nozzle for showering a clean condensate of flammable solvent vapor on an article, and a distillation column for supplying clean flammable solvent vapor to the vapor rinsing / solvent shower chamber, wherein the washing The solvent in the tank is taken out and evaporated, and the impurities accumulated in the solvent in the cleaning tank are separated and removed by distillation to make a clean solvent vapor, and the solvent liquid content attached to the article by a clean dry gas. An ultrasonic cleaning / drying apparatus is provided, which comprises:

[0009]

In the cleaning / drying method of the present invention, for example, in the case of the apparatus shown in FIG.
After the solvent is washed, the article 2 enters the solvent shower chamber 8 ', the washing liquid adhering to the article is washed off by the shower of the condensate of the clean solvent, and then enters the vapor rinse chamber 8 to remove impurities in the distillation column 12 for separation. After rinsing and drying with the cleaned clean solvent vapor, ventilation drying chamber 14
Then, the solvent liquid content adhering to the article is dried by the warm air cleaned in the gas circulation line 19. In addition,
Although not shown, when the article is rinsed and dried with a clean combustible solvent vapor, and the article is provided with a vapor rinse / solvent shower chamber having a nozzle for showering a condensate of the clean combustible solvent vapor, the article is Enter the steam rinsing / solvent shower room, wash away the cleaning liquid adhering to the article by showering the condensate of the clean solvent, and then distilling tower 1
After rinsing and drying with the clean solvent vapor separated from the impurities in 2 and separated, the air enters the ventilation drying chamber 14.

In the present invention, the solvent in the washing tank is supplied to the distillation column to purify and separate only the solvent component. In that case, the packed tower,
By using a distillation tower of the type such as a wetting wall tower, a bubble tower, a bubble bell tower, etc., if there is a component that forms an azeotropic mixture with a flammable solvent among the fats and oils that are dirt components, azeotrope with the fats and oils. By adding other solvents that cause water, for example, water, benzene, hexane, toluene, etc., it is possible to positively discharge the dirt components together with the added solvent, while obtaining high-purity azeotropic mixed solvent vapor as heating vapor. be able to. Therefore,
Dirt components are not accumulated in the cleaning tank, the solvent liquid in the cleaning tank is always kept clean, and there is no need to replace the solvent.

In the present invention, it is preferable that the closed system is used, and the oxygen concentration in the system is controlled to be less than the explosive concentration by feeding an inert gas into the system. Specifically, as a flammable solvent, When isopropanol (IPA) is used, it is controlled to 10% or less, preferably 8% or less.
If the oxygen concentration exceeds 17%, the risk of explosion and fire increases, which is not preferable. In this way, by controlling the oxygen concentration in the system within the prescribed range, there is no risk of fire or explosion even if a flammable solvent is used, and leakage of the flammable solvent can also be prevented, thus stabilizing dry products. Can be planned.

Further, the low concentration solvent vapor in the aeration drying chamber 14 enters the gas circulation line, and after the solvent is recovered by the condenser, the drying gas is blown from the blowing nozzle to the aeration drying chamber through the heater and the filter. The solvent liquid adhering to is dried to finish drying. Further, the oxygen concentration is constantly detected in the gas circulation line, and when the oxygen concentration is high, an inert gas such as nitrogen gas is fed so as to have a predetermined oxygen concentration.

Further, it is preferable that a front chamber is provided in parallel with the present apparatus, and this chamber is washed and dried and kept at a negative pressure from the outside air, because the vapor of the solvent does not directly leak to the outside. Examples of the cleaning agent used for ultrasonic cleaning include organic solvents, alkaline detergents, surfactants, emulsifying detergents, acidic detergents, and mixtures thereof, but in the present invention, among the organic solvents, trichloroethane, trichlorethylene, Not only flammable solvents such as perchlorethylene and freon 113 can be used, but also flammable flammable solvents such as isopropanol (IPA), solvent naphtha, thinner, benzine, acetone and alcohol can be used. It is suitable. Further, as the inert gas used for controlling the oxygen concentration in the system and for finishing drying of the article, besides nitrogen gas, argon gas, carbon dioxide gas or the like can be used.

[0014]

EXAMPLES The present invention will now be described in more detail with reference to the illustrated examples, but the present invention is not limited to these examples.

(Embodiment 1) FIG. 1 is a schematic view showing an embodiment of the ultrasonic cleaning / drying apparatus of the present invention, and this apparatus can be preferably applied to the cleaning / drying of precision small articles. First, nitrogen gas is fed into the cleaning / drying chamber 1 to
After the oxygen concentration in the inside is set to a set value, a cleaning solvent is filled. Next, 300 × 2 in which 7 kg of a metal part (hereinafter, referred to as an article) 2 for cleaning with oil stains by press working was stored.
00 × 150 mm (height) basket-shaped container 3
The pressure in the room is fed into the front chamber 4 where the pressure in the room is kept at a lower negative pressure than the outside air and the cleaning / drying chamber 1. The front chamber 4 is provided with a flammable solvent detector (not shown) for detecting vapor of the flammable solvent leaking out from the cleaning / drying chamber 1 in a small amount. Also,
The partition wall between the front chamber 4 and the washing / drying chamber 1 has a shielding door 5,
5'is provided. The front chamber 4 plays a role as a buffer chamber for preventing the vapor of the solvent leaking from the cleaning / drying chamber 1 from being directly discharged to the outside.

Next, the article 2 enters the point A of the washing / drying chamber 1 and then 400 × 300 × 350 mm filled with a solvent solution isopropanol (IPA) for washing at point B by a suspending device (not shown). It is dipped in the cleaning tank 6 of (height), and while being vertically rocked, it is cleaned by ultrasonic waves oscillated from the ultrasonic oscillator 7 of 600 W and a frequency of 28 KHZ. Next, the article 12 is pulled up to the point C of the washing / drying chamber 1 and cooled in the solvent shower chamber 8 ′ by the condenser 9 to become liquid, and the clean solvent vapor injected from the injection port 11 by the pump 10 is discharged. The shower cleaning is performed with the condensate to wash away the cleaning liquid adhering to the article 2 and reduce the temperature of the article 2 to facilitate the vapor condensation.

Then, the article 2 is pulled down to point D,
In the steam rinsing chamber 8, a distillation column (diameter 50 mm, diameter 50 mm, with a cleaning solvent 0.25 l / min filled with a stainless wire net up to 1000 mm by a pump 11 from a cleaning tank 6
(Higher 1500 mm) 12 and the vapor is rinsed by the high-purity solvent vapor heated and evaporated in the distillation column 12 and further vapor-dried by the vapor. The dirt component in the solvent is discharged as a drain 13 from the bottom of the distillation column 12.

Next, the article 2 is pulled up to the point A, where the low concentration solvent vapor in the aeration drying chamber 14 enters the gas circulation line 19 and the solvent is recovered in the condenser 15, and then the circulation blower 16 and the heater. After passing through the filter 17 and the filter 18, the solvent liquid adhering to the article 2 which is blown out from the blowout port 20 after being made into clean warm air is completely dried. The oxygen concentration in the gas circulation line 19 is constantly detected, and when the oxygen concentration is high, nitrogen gas is fed so that the oxygen concentration becomes a predetermined value.

The article 2 which has been washed and dried by the above operation is taken out through the front chamber 4. Even when 50 batches of the above washing and drying operation were repeated, the washing effect was not different from the case where a new solvent was used. Also, during this period, the solvent is appropriately replenished (approximately 1 kg
/ 10 batch) was all right.

(Comparative Example 1) FIG. 2 is a schematic view showing an example of a conventional ultrasonic cleaning / drying apparatus.
The same method as in Example 1 was used, and the same article 2 as in Example 1 was washed and dried in exactly the same procedure as in Example 1. Unlike Example 1, the distillation column 12 is not used as in Example 1,
The solvent in the cleaning tank 6 was filtered through a pump 22 and a filter 23 having an opening of 5 μm by circulating the solvent at a liquid volume of 5 l / min. Further, the solvent vapor for rinsing and drying the article was generated in the evaporation tank 24 by the heating medium at 15 kg / Hr.

Since this apparatus does not use the distillation column 12 as in the first embodiment, the solvent in the cleaning tank 6 and the evaporation tank 24 has a problem that a dirt component accumulates every time cleaning is repeated.
When the article is washed and dried by the above method, it is 1 to 20.
There was no stain on the articles in batches, there was a little stain in 21 to 30 batches, and stains (stains) became severe after 31 batches.

[0022]

As described above, according to the present invention,
Since the solvent in the cleaning tank is sent to the distillation column and the article is rinsed and dried by the clean solvent vapor, the solvent in the cleaning tank is always kept clean, the rinsing effect of the article is always maintained, and the article is soiled ( Can be dried without stains.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an ultrasonic cleaning / drying apparatus of the present invention.

FIG. 2 is a schematic diagram showing an example of a conventional ultrasonic cleaning / drying apparatus.

[Explanation of symbols]

1 washing and drying room, 2 washing articles, 3 containers, 5, 5 '
Shielding door, 6 Cleaning tank, 7 Ultrasonic transmitter, 8 Vapor rinse room, 8'solvent shower room, 9 Condenser 10 Pump, 11 pump, 12 Distillation tower, 13 Drain, 14 Aeration drying room, 15 Condenser, 16 Circulation blower, 17 heater, 18 filter, 19 gas circulation line, 20 outlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikazu Ogawara Kakoki Co., Ltd. 3847 Ikebe-cho, Midori-ku, Yokohama-shi, Kanagawa

Claims (5)

[Claims] 1. An ultrasonic cleaning / drying method comprising ultrasonically cleaning an article with a flammable solvent contained in a cleaning tank, and then rinsing and drying with vapor of the solvent, wherein the solvent in the cleaning tank is distilled. It was supplied to the column, the solvent was evaporated in the distillation column, the impurities accumulated in the solvent in the cleaning tank were separated and removed by distillation, and the rinse and drying of the article were performed with clean solvent vapor. A characteristic ultrasonic cleaning and drying method. 2. The ultrasonic cleaning / drying method according to claim 1, wherein the oxygen concentration in the system is controlled to be less than the explosive concentration by feeding an inert gas into the closed system. 3. A different solvent which is azeotropic with a flammable solvent,
The ultrasonic cleaning and drying method according to claim 1 or 2, wherein the method is added to the flammable solvent. 4. A cleaning tank accommodating a combustible solvent and an ultrasonic cleaning device for ultrasonically cleaning an article, and a cleaning tank provided on an upper portion of the cleaning tank for rinsing the article with a clean combustible solvent vapor. A vapor rinse chamber for drying, a solvent shower chamber provided above the vapor rinse chamber and having a nozzle for showering a condensate of clean flammable solvent vapor on the article, and a clean flammable solvent vapor for the vapor rinse chamber. A distillation column for supplying, wherein the solvent in the cleaning tank is taken out and evaporated, and the impurities accumulated in the solvent in the cleaning tank are separated and removed by distillation to obtain a clean solvent vapor; An ultrasonic cleaning / drying apparatus comprising an aeration drying chamber for drying a solvent liquid component attached to an article by a dry gas. 5. A cleaning tank accommodating a combustible solvent and an ultrasonic cleaning device for ultrasonically cleaning an article, and a cleaning tank provided above the cleaning tank for rinsing the article with a clean combustible solvent vapor. A vapor rinse / solvent shower room having a nozzle for drying and condensing the clean condensate of flammable solvent vapor onto the article, and a distillation tower for supplying clean flammable solvent vapor to the vapor rinse / solvent shower room. The solvent in the cleaning tank is taken out and evaporated, and the impurities accumulated in the solvent in the cleaning tank are separated and removed by distillation to make a clean solvent vapor. A distillation tower is attached to the article by a clean dry gas. An ultrasonic cleaning / drying apparatus comprising an aeration drying chamber for drying the solvent liquid component.