JPH02280880A - Method for operating washing apparatus using organic solvent - Google Patents

Abstract

PURPOSE:To eliminate the leakage of the vapor of an org. solvent to the outside by operating a vacuum pump in such a state that the org. solvent is introduced into a washing tank having an object to be washed received therein and discharging the air remaining in the upper space of the washing tank. CONSTITUTION:The vapor of the org. solvent in the gaseous mixture discharged by a vacuum pump 13 and sent into a distiller 12 being a solvent recovery means through a discharge pipe 19 and a vapor discharge pipe 14 is condensed and liquefied by the cooler 11 provided to the upper part of the distiller 12 to be recovered in a storage tank 6. The solvent not recovered by the cooler 11 is condensed and recovered by a secondary cooler 21 and a very small amount of the solvent vapor incapable of being recovered by the secondary cooler 21 is further collected by an activated carbon filter 22. Therefore, even when the org. solvent is sent in a washing tank 2 and the vacuum pump 13 is operated, the vapor of the org. solvent is not leaked to the outside.

Description

Detailed Description of the Invention (Industrial Application Field) A method of operating a cleaning device using an organic solvent according to the present invention is a method for cleaning dirt such as oil adhering to the surfaces of various articles using an organic solvent such as Freon. This is used when operating a cleaning device that cleans the tank.By preventing air from remaining in the cleaning tank, the internal space of the cleaning tank can be used effectively and the cleaning device can be made more compact. It is.

(Prior art) Molds, porous sintered metal for air bearings, IC boards, etc.
BACKGROUND OF THE INVENTION It is common practice to clean oil and other stains adhering to the surfaces of various articles by using organic solvents such as fluorocarbons and trichlorethylene as a cleaning liquid.

An example of a cleaning device that performs cleaning work by using such an organic solvent as a cleaning liquid is disclosed in Utility Application No. 1983-
This will be explained using the device shown in No. 54595 as an example.

As shown in the drawing, this cleaning device includes a cleaning tank 2, which has a cylindrical shape with an open top and a lid 1 that can airtightly close the top opening, and a heater 3 for heating and evaporating the organic solvent.
a steam supply means 4 which has a built-in organic solvent vapor and sends organic solvent vapor into the inside of the cleaning tank 2 through a pipe 5, a storage tank 6 which stores a cleaning organic solvent to be sent into the inside of the cleaning tank 2, and this storage tank. It consists of two pipes 7.8 connecting the cleaning tank 6 and the cleaning tank 2, and a liquid feeding pump 9 installed in the middle of one of the pipes 8.
supply and discharge means 20 for supplying and discharging a liquid organic solvent between;
A distiller 12 that combines a heater 10 for heating and evaporating a liquid organic solvent and a cooler 11 for condensing organic solvent vapor, and a distiller 12 that sends the condensed organic solvent to the storage tank 6 and a cleaning tank 2. An exhaust pipe 14 that is connected to the ends of an intake pipe 16 that sends air and an exhaust pipe 19 that is provided with a vacuum pump 13 in the middle, and that sends the organic solvent vapor discharged from the cleaning tank 2 to the distiller 12; It is composed of an exhaust pipe 15 for discharging air from the cleaning tank 2.

When cleaning the object 17 to be cleaned using the cleaning apparatus of the earlier invention configured as described above, the lid 1 is opened and the object 17 is stored inside the cleaning tank 2, and then the lid 1 is closed. After closing, operate the vacuum pump 13, and through the exhaust pipe 15,
The air in this cleaning tank 2 is exhausted.

After discharging the air in the cleaning tank 2, the organic solvent in the storage tank 6 is sent into the cleaning tank 2 through the pipe 7 constituting the supply/discharge means 20, and the object to be cleaned 17 is cleaned. By energizing the ultrasonic vibrator 18.18 fixed to the bottom of the tank 2, ultrasonic vibration is applied to the organic solvent in the cleaning tank 2, so that the object 17 to be cleaned can be efficiently cleaned.

After the cleaning work with the liquid organic solvent is completed, by operating the liquid feeding pump 9 constituting the supply/discharge means 20,
While the liquid organic solvent in the cleaning tank 2 is gradually returned to the storage tank 6 through the pipe 8, organic solvent vapor is supplied into the cleaning tank 2 from the steam supply means 4.

As a result, a part of the object 1 to be cleaned in the cleaning tank 2 is exposed above the surface of the liquid organic solvent, and the vapor of the organic solvent is condensed in this exposed part, and this condensation is used to remove the object 1 to be cleaned. A so-called steam cleaning process is performed in which the surface of the substrate is cleaned.

After all the liquid organic solvent in the cleaning tank 2 is returned to the storage tank 6 while performing steam cleaning, the vacuum pump 13 installed in the middle of the discharge pipe 19 is operated to remove the remaining liquid in the cleaning tank 2. The organic solvent vapor is discharged into the distiller 12 through the exhaust pipe 14 . In this way, the organic solvent vapor discharged into the distiller 12 through the discharge pipe 19 and the exhaust pipe 14 is condensed and liquefied by the cooler 11 provided in the distiller 12 and recovered. The organic solvent vapor that has not been completely recovered by the cooler 11 is recovered by the secondary cooler 21, and the trace amount of organic solvent vapor that has also passed through the secondary cooler 21 is collected by the activated carbon filter 22.

When the inside of the cleaning tank 2 reaches a predetermined degree of vacuum with the operation of the vacuum pump 13, the vacuum pump 13 is stopped,
Air is sent into the cleaning tank 2 through the intake pipe 16.

As a result, when the pressure inside the cleaning tank 2 rises to approximately atmospheric pressure, N1 of the cleaning tank 2 is opened and the object 17 to be cleaned which has been cleaned is taken out.

(Problem to be solved by the invention) However, the conventional method configured and operated as described above,
Or when operating the cleaning device according to the earlier invention,
This causes the following inconvenience.

That is, to start the cleaning work, after storing the object 17 to be cleaned inside the cleaning tank 2, the lid 1 is closed, and the vacuum pump 13 is operated to exhaust the air inside the cleaning tank 2. Although the organic solvent is made to spread to every corner of the object 17 to be cleaned, it is unavoidable that some air remains in the cleaning tank 2 due to problems with the capacity of the vacuum pump 13.

In this way, if the cleaning liquid is sent into the cleaning tank 2 through the pipe 7 while some air remains in the cleaning tank 2, air will be present in the upper space 25 of the cleaning tank 2. As a result, the pressure in the upper space 25, which is determined by the sum of the partial pressure of the residual air and the partial pressure of the organic solvent vapor, increases by the amount of the residual air.

On the other hand, when the inside of the cleaning tank 2 containing an organic solvent such as fluorocarbon becomes positive pressure, in order to prevent the organic solvent vapor from leaking, Ml installed at the upper end opening of the cleaning tank 2 must be 2
It is necessary to provide a mechanism for tightening to press against the backing provided on the upper edge of the cleaning device, which inevitably complicates the structure of the cleaning device.

In addition, if the airtightness of the lid becomes poor due to poor tightening or damage to the backing, the vapor of the organic solvent present in the cleaning tank 2 may leak into the atmosphere, resulting in damage to the ozone layer, etc. It causes environmental destruction.

For this reason, the present inventor previously invented a cleaning method that prevents the leakage of organic solvent vapor by maintaining the inside of the cleaning tank 2 at negative pressure during the cleaning operation (Japanese Patent Application No. 1-17516). As mentioned above, when the pressure in the upper space 25 increases by the amount of residual air, the pressure in the cleaning tank 2 becomes higher than the atmospheric pressure as the cleaning process progresses (the inside of the cleaning tank 2 becomes positive). This increases the possibility that the organic solvent will leak, making it difficult to prevent organic solvent leakage.

In order to keep the pressure in the upper space 25 of the cleaning tank 2 low regardless of the presence of residual air, the ratio of the volume of the upper space 25 to the total internal volume of the cleaning tank 2 may be increased. However, the volume of the part that can store the organic solvent for cleaning (the volume obtained by subtracting the volume of the upper space 25 from the total internal volume of the cleaning tank 2) decreases accordingly, making it difficult to clean the large objects 17 to be cleaned. . Furthermore, if a large object to be cleaned 17 is to be cleaned, the size of the cleaning tank 2 will increase.

The method of operating a cleaning device using an organic solvent according to the present invention solves the above-mentioned disadvantages.

(Means for Solving the Problems) As shown in the drawings, the cleaning equipment using an organic solvent operated by the method of the present invention, as shown in the drawings, It is composed of a cleaning tank 2 that can be sealed tightly when stored, a storage tank 6, a pipe 7, etc., and a supply means that can freely feed an organic solvent for cleaning such as fluorocarbon into the cleaning tank 2, and a It is constructed by incorporating a vacuum pump 13 for discharging the gas present in the upper space 25, a cooler 11, etc., and the gas discharged from this vacuum pump 13 can be fed freely, and the organic solvent present in this gas can be removed. and a solvent recovery means for recovering vapor.

This cleaning device performs the cleaning operation while maintaining the inside of the cleaning tank 2 at negative pressure by continuing to operate the vacuum pump 13 throughout the cleaning operation.

For operating cleaning equipment that uses such organic solvents,
In the method of claim 1 of the method of the present invention, the object to be cleaned 17 is stored in the cleaning tank 2 with the lid 1 open, and after the cleaning tank 2 is sealed by the M1, the storage While an organic solvent such as fluorocarbon is being fed into the cleaning tank 2 through the supply means consisting of the tank 6, the pipe 7, etc., the vacuum pump 1
3, the air remaining in the upper space of the cleaning tank 2 is discharged.

In the method of claim 2, the vacuum pump 13 is operated before the organic solvent is fed into the cleaning tank 2 by the supply means. The air discharged by this operation is directly discharged into the atmosphere without passing through the distiller 12, which is a solvent recovery means. When the air in the cleaning tank 2 has been exhausted to a certain extent by operating the vacuum pump 13, an organic solvent is sent into the cleaning tank 4'I2, and the vapor and air generated by the evaporation of this solvent are collected by a solvent recovery means. It is sent to the distiller 12 which is

(Function) Claim 1 of the operating method of the present invention configured as described above
In the case of the method described in , the gas present in the upper space 25 of the cleaning tank 2 becomes a mixed gas of air and organic solvent vapor as the vacuum pump 13 operates.

When this mixed gas is further continuously discharged by the vacuum pump 13, the proportion of air in the mixed gas gradually decreases.

That is, the organic solvent vapor is replenished one after another by the evaporation of the liquid organic solvent supplied into the cleaning tank 2, but since air is not replenished at all, the air occupied in the above-mentioned mixed gas is The ratio gradually decreases until finally, cleaning tank 2
The inside of the upper space 25 is filled with only organic solvent vapor.

The pressure of the organic solvent vapor in the head space 25 is
As long as the temperature inside the upper space 25 is kept below a certain level, it will not exceed 1 atm, so the pressure inside the upper space 25 should be less than 1 atm (positive pressure).
It is easy to keep it.

Exhausted by vacuum pump 13, discharge pipe 19, exhaust pipe 1
4, the solvent vapor in the mixed gas is sent into the distiller 12, which is a solvent recovery means, and is condensed and liquefied by the cooler 11 provided at the upper part of the distiller 12, and is recovered into the storage tank 6.

Further, the solvent vapor that was not completely recovered by the cooler 11 is condensed and recovered by the secondary cooler 21, and the trace amount of solvent vapor that could not be recovered by the secondary cooler 21 is further collected by the activated carbon filter 22. be captured. However, if the capacity of the cooler 11 is sufficient, the secondary cooler 21 and activated carbon filter 22 can be omitted.

Therefore, even if the vacuum pump 13 is operated while feeding the organic solvent into the cleaning tank 2, the organic solvent vapor will not leak outside because the organic solvent vapor is heavier than air.

Furthermore, in the case of the method described in claim 2, since the amount of air sent into the distiller 12, which is the solvent recovery means, can be suppressed to a small level, the organic solvent vapor that escapes to the outside of the distiller 12 along with the air can be suppressed. The amount of can be reduced.

(Effects of the Invention) The method of operating a cleaning device using an organic solvent of the present invention is configured and operates as described above, so that the pressure inside the cleaning tank can be reduced without increasing the upper space of the cleaning tank. Positive pressure can now be easily maintained, and sufficiently large objects can be cleaned while reliably preventing leakage of organic solvent vapor without making the cleaning tank particularly large.

[Brief explanation of drawings]

The drawing is a schematic vertical sectional view showing an example of a cleaning device to which the present invention is applied. 1: Lid, 2: Cleaning tank, 3: Heater, 4: Steam supply means,
5: Pipe, 6: Storage tank, 7.8: Pipe, 9: Liquid pump, 1
0: heater, 11: cooler, 12: distiller, 13: vacuum pump, 14: exhaust pipe, 15: exhaust pipe, 16: intake pipe,
17: Object to be cleaned, 18: Ultrasonic vibrator, 19: Discharge pipe,
20: supply/discharge means, 21: secondary cooler, 22: activated carbon filter, 23.24: valve, 25: upper space. Patent applicant: Chiyoda Seisakusho Co., Ltd. Representative: Kinzo Koyama (and 1 other person)

Claims (2)

[Claims] (1) A cleaning tank that can be sealed while storing the items to be cleaned,
A supply means capable of freely feeding an organic solvent for cleaning into the cleaning tank, a vacuum pump discharging the gas present in the upper space of the cleaning tank, and a supply means capable of freely feeding the gas discharged from the vacuum pump. A method of operating a cleaning device using an organic solvent, comprising a solvent recovery means for recovering organic solvent vapor present in the cleaning tank, and cleaning work is performed while maintaining the inside of the cleaning tank at negative pressure. After storing the object to be cleaned in the cleaning tank and sealing the cleaning tank, the organic solvent is fed into the cleaning tank by the supply means, and the vacuum pump is operated to remove the upper part of the cleaning tank. A method of operating cleaning equipment that uses organic solvents to exhaust air remaining in the space. (2) The method for operating a cleaning device using an organic solvent according to claim 1, wherein the air in the cleaning tank is discharged into the atmosphere by a vacuum pump before the organic solvent is sent into the cleaning tank by the supply means. .