JPS5939162B2 - washing drying equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for washing and drying articles such as electronic parts, wafers, lenses, etc. that require highly clean drying.

As a washing liquid suitable for such drying, trichlorotrifluoroethane (Freon 11
3) belongs to the publicly known.

When the item to be cleaned is immersed in this washing liquid and rinsed, the water adhering to the item floats to the top of the washing liquid due to buoyancy because its specific gravity is much smaller than the specific gravity of the washing liquid. It is. To explain this in detail, first, the alcohol in the washing liquid dissolves into the water adhering to the article, and the resulting ecanol aqueous solution wets the surface of the article, thereby lowering the surface tension of the article. It separates from the surface of the article and rises to the surface of the washing liquid due to buoyancy. Since various gold layer ions, anions and colloidal substances originating from the adhered water are dissolved in this floating aqueous solution, the surface of the article to be cleaned can be purified. The advantage of this type of cleaning method is that the boiling point of CFCs that may remain on the surface of the articles pulled up from the washing liquid is low, so no evaporation energy is required for drying, and the CFCs float to the top of the washing liquid. The contaminated aqueous solution can be purified by conventional purification means such as rectification and easily returned to the cleaning system for reuse. However, the above-mentioned means may still be insufficient for washing and purifying articles that require extremely high levels of purification.
That is, strictly speaking, the equilibrium concentration of the above-mentioned ethanol aqueous solution with the washing liquid is about 50%, so when the article is lifted from the washing liquid, the surface of the article is wet with a thin film of about 50% ethanol aqueous solution. It's getting old. Therefore, if the aqueous solution is contaminated, it will remain as a stain on the surface of the article, albeit in a very small amount. For careful cleaning, there is also a known method for carrying out so-called steam cleaning, in which the item is immersed in a washing liquid, then pulled out, and then immediately placed in the washing liquid vapor without being left to dry. However, in this case, since the liquid condensing on the surface of the article has the same composition as the washing liquid, the equilibrium is not disturbed and the ethanol aqueous solution cannot be removed. Therefore, in reality, extremely high-speed cleaning effects cannot be achieved by this means. The present invention provides a washing device that solves the above problems, and includes a boiling tank provided in the known washing tank main body, a cooling deicing section newly installed outside the main body, and a washing liquid in the main body. The condensate generated by the steam condenser is guided to the cooling de-icing section, water is removed from the condensate, and the washing liquid, whose moisture content has been reduced by cooling, is transferred to the cooling de-icing section. It is characterized in that it is connected so as to be introduced into a boiling tank.

This will now be explained with reference to attached FIGS. 1 and 2, which are examples of implementation.

The main body 10 of the device in this example is a rectangular body with an open upper part as usual, and inside it is a vertical partition wall 10 that reaches the bottom plate.
It is divided into a steam tank 13, a boiling tank 12, a dehydration tank 11, a liquid separation tank 14, and an intermediate tank 15 from the right side by a, 10b, 10c, and 10f.

In addition, the separation tank 14 has shallow partition walls 10d and 1 that do not reach the bottom plate.
0e to form a stationary area 14a for the washing liquid,
This facilitates two-phase separation of the washing liquid and the aqueous solution. Furthermore, since the height of each of the above-mentioned partition walls is lower than the height of the tank, the upper half of the tank forms an upper space 16 common to each tank, and this space is used to store the articles to be washed. It also serves as an entrance and exit passageway. A condenser 1 is provided on the four walls of the tank forming the four circumferences of this upper common space 16. The condensed washing liquid vapor is guided from the pipe 5 to a cooling water removal section 30 provided separately from the main body. The main parts of the cooling water removal section are:
It is a tank body in which a brine cooling corrugated pipe 33 is arranged, vertical partition walls 30a and 30b are provided inside, and a water removal chamber 31
, and a liquid storage chamber 32. The aqueous phase recovery section 20 is not particularly different from one that is attached as a part of a known washing device. A rectification tower is illustrated as a typical example. The main parts of the device of the present invention are as described above,
Other accessories are of course included, but I will describe them as I explain how to use this device.

Freon 113 containing a few percent of ethanol, which is the washing liquid placed in the tank forming the main body 10, overflows the partition wall 10b from the boiling tank 12, enters the dehydration tank 11, and enters the dehydration tank 11. 10c and enters the liquid separation chamber 14.The articles to be washed are first immersed in the washing liquid in the dehydration tank 11 through the upper common space 16 of the tank, which is a passage. It is then pulled up and immersed in the boiling washing liquid in the adjacent boiling tank 12, then pulled up through the passage 16 and air-dried.

At this time, the articles pulled up from the boiling tank are placed in the adjacent steam tank 13.
It can be transferred to the interior and subjected to so-called steam bath cleaning. As described above, cleaning and purification of the article is completed with just this operation. Instead of air drying, warm air may be blown to speed up the drying process. The washing liquid that has taken adhering water from the surface of the article is made to float, overflows the partition wall 10c, and enters the liquid separation chamber 14, and due to the static effect caused by the presence of the partition walls 10d and 10e, the washing liquid phase is placed above the stationary area 14a. An aqueous alcohol solution is separated into an aqueous phase W1.

This aqueous phase is introduced into the rectification column 21 through the pipe 3, and the ethanol distilled there passes through the pipe 4 and is transferred to the main body 10.
The materials will be returned and reused in appropriate parts. Dirty water remaining in the pot is discharged and disposed of through a pipe 22. In the separation tank 14, the separated washing liquid constituting the lower phase overflows the partition wall 10f and enters the intermediate tank 15, and then is passed through the circulation pipe 7 consisting of the pipe 7a, the pump 7b, and the pipe 7c to the dehydration tank. 11 and the process is repeated.

A part of the washing liquid is sent to the steam tank 13 through the pipe line 8, and is evaporated by the heater 2c, forming a steam bath in the tank. Note that a heater 2b is also installed at the bottom of the boiling tank 12 to maintain the washing liquid in a boiling state. Therefore, the articles to be cleaned are subjected to liquid phase cleaning at boiling temperature and then, if necessary, steam bath cleaning. The dehydration tank 11 may also be provided with a heater 2a, but this is because it is easier to dehydrate the washing liquid when it is heated than when it is not heated, and it is easier to dehydrate the washing liquid if it is used in a boiling state. It is the best. In the apparatus of the present invention, as described above, the washing liquid is constantly vaporized in the boiling tank 12 and the steam tank 13, and the upper space 16 of the main tank is filled with the vaporized liquid.

This steam is cooled and condensed in the condenser 1, then led to the cooling water removal section 30 through the pipe 5, and indirectly cooled with brine through the cooling corrugated pipe 33. The lower the cooling temperature, the better, as long as it does not freeze. In the water removal chamber 31, which is kept stationary by the partition wall, two phases are separated: an aqueous phase W2 on the upper side and a washing liquid phase on the lower side, and this aqueous phase W2 is removed from the drain pipe 34. Further, the washing liquid shown as being temporarily stored in the liquid storage chamber 32 formed by the partition wall is returned to the boiling tank 12 via the pipe line 6. The apparatus of the present invention is provided with such a cold water removal section 30, and the reason why the washing liquid after cooling and water removal is returned to the boiling tank is as follows. That is, FIG. 3 is a graph showing the relationship between the temperature and water solubility of a mixed washing liquid of Freon 113/Ethanol 96/4.

In this figure, the solubility of water at about 30°C, which is the boiling point of this washing liquid, is about 0.27 (!), but this is about 1
When cooled to 0°C, the solubility of water is approximately 0.230! ). By the way, when an article to be washed is lifted out of the dehydration tank, as mentioned above, the concentration of the water in the ethanol aqueous solution remaining in a thin film on the surface of the article to be washed depends on its temperature. (e.g. 50%) value of the saturation solubility at . Even if it is subjected to steam bath cleaning using washing liquid in this state, the steam is also saturated with water, so the steam bath cleaning will not be effective. However, with the device of the present invention, the water phase W2 in the washing liquid is removed in the cooling water removal section 30,
If the washing liquid itself is cooled to 10°C, this washing contains only 0.23% water. When this material is returned to the boiling tank 12 through the pipe 6 and heated there to a boiling state, the washing liquid under the boiling state is in a water-unsaturated state. If the article pulled up from the dehydration tank is immersed in this water-unsaturated boiling tank washing solution, the water in the adhered thin film will naturally dissolve into the boiling washing solution. As the water dissolves, the ions and colloids contained therein also migrate into the boiling washing liquid. In other words, surface purification of the article progressed, and a much higher degree of purification was achieved than when the condensed washing liquid was returned to the boiling tank without using a cooling water removal section. In order to reduce the amount of water in the condensed washing liquid as much as possible, there is a proposal to adsorb the water to zeolite, but the regeneration of zeolite requires a temperature of about 300'C.
Since this method requires heating, it is inevitably disadvantageous compared to the present invention. It goes without saying that the amount of washing liquid overflowing from the boiling tank to the dehydration tank should be equal to the amount of washing liquid returned from the pipe 6 and cooled to balance the material balance. Furthermore, a steam bath in which the articles to be washed are heated by immersion in the boiling washing liquid may be installed outside the system.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a graph showing the solubility of water in the washing liquid used in the present invention. 1 is a condenser, 2 (a-c) is a heater, 3, 4, 5, 6,
7, 8, 9 are pipes, 10 is a main body, 10 (a-f) is a partition, 11 is a dehydration tank, 12 is a boiling tank, 13 is a steam tank, 14
15 is a liquid separation tank, 15 is an intermediate tank, 16 is an upper common space, 20 is an aqueous phase recovery section, 30 is a cooling water removal section, 30 (a-b) is a partition wall, 31 is a water removal chamber, 32 is a liquid retention chamber , 33 is a cooling spiral pipe, 34
is a drain pipe.

Claims (1)

[Claims] 1. A main body having at least a dehydration tank, a boiling tank, a steam tank, and a condenser, and a cooling water removal part, in which the condensate generated in the condenser is guided to the cooling water removal part, and the cooling water removal part is carried out. An apparatus for washing and drying articles using trichlorotrifluoroethane containing ethanol as a washing liquid, characterized in that the apparatus is connected so as to be returned to the boiling tank afterwards.