JP2010082524A - Recycling method of cleaning liquid of vacuum washing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycling method of a cleaning liquid, a method capable of removing low boiling or high boiling components that are close to a boiling point range of a hydrocarbon based cleaning liquid. <P>SOLUTION: The cleaning liquid after washing is collected and, using a vacuum distillation apparatus 5, factionated into cleaning liquid components and impurity components of different boiling points to recycle the cleaning liquid components. Mist or gaseous components, which are unfactionated by the vacuum distillation apparatus 5 and sucked into a vacuum pump 8 for the distillation apparatus for exhausting therefrom, are liquefied by a condenser 11 and an after-cooler 12 which are installed along the exhaustion passage of the vacuum pump 8 for the distillation apparatus 5, and then discarded. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning liquid regeneration method in a vacuum cleaning apparatus using a hydrocarbon-based cleaning liquid.

  In recent years, before and after heat treatment of metals and after the pressing process, vacuum cleaning apparatuses using hydrocarbon-based cleaning liquids have been used in place of conventional organic solvent-based cleaning liquids. Such a vacuum cleaning apparatus is disclosed in Patent Document 1, for example.

  Conventionally, the hydrocarbon-based cleaning liquid of the vacuum cleaning apparatus is regenerated by the method shown in FIG. That is, the cleaning liquid after cleaning the object to be cleaned in the vacuum cleaning apparatus 2 is once collected in the contaminated liquid tank 4 and sent to the vacuum distillation apparatus 5. In the vacuum distillation apparatus 5, the components of the hydrocarbon-based cleaning liquid are distilled and sent from the regenerated liquid tank 6 to the oil cleaning tank 3 and reused as the cleaning liquid. Components having a high boiling point that are not distilled in the vacuum distillation apparatus 5 are sent to the waste liquid tank 7 and discarded. Further, when the vacuum distillation apparatus 5 is evacuated without being fractionated by the vacuum distillation apparatus 5, the mist or gaseous component that has flowed to the distillation apparatus vacuum pump 8 side is exhausted from the distillation apparatus vacuum pump 8. The condenser 11 (condenser) provided on the inlet side of the passage and the aftercooler 12 provided on the outlet side of the exhaust passage of the vacuum pump 8 for distillation apparatus are liquefied, and these components are also returned to the oil washing tank 3. And reused.

JP 2006-231273 A

  However, since the hydrocarbon-based cleaning liquid is not a single component, the boiling point differs for each component. And the low boiling point component and high boiling point component close | similar to the boiling point range of a water | moisture content or a hydrocarbon type washing | cleaning liquid have adhered to the to-be-cleaned material wash | cleaned with a vacuum cleaning apparatus. However, in the vacuum distillation apparatus 5 described above, it is difficult to fractionate components having a boiling point close to that of the hydrocarbon-based cleaning liquid, and such components flow to the distillation apparatus vacuum pump 8 and are reused as cleaning liquid. It was. As a result, impurities accumulate in the cleaning liquid, resulting in poor cleaning performance, poor drying after cleaning, and generation of oily smoke. To prevent this, the cleaning solution had to be replaced periodically.

  An object of the present invention is to provide a cleaning liquid regeneration method that can remove low-boiling components and high-boiling components close to the boiling range of hydrocarbon-based cleaning liquids.

  In order to solve the above problems, the present invention is a method for regenerating a cleaning liquid used in a vacuum cleaning apparatus, which collects the cleaning liquid after cleaning and separates cleaning liquid components and impurity components having different boiling points with a vacuum distillation apparatus. The components of the cleaning liquid are regenerated and the components sucked into the vacuum pump for the distillation apparatus that is exhausted from the vacuum distillation apparatus without being fractionated by the vacuum distillation apparatus are provided along the exhaust passage of the vacuum pump. Provided is a method for regenerating a cleaning liquid in a vacuum cleaning apparatus, wherein the cleaning liquid is liquefied and discarded by a condenser and a cooler.

  Since the components that are not fractionated by the vacuum distillation apparatus contain a large amount of impurities, discarding the components reduces the contamination of the regenerated cleaning liquid and allows a stable cleaning process to be continued.

  Further, it is preferable that the components sucked into the vacuum pump for the cleaning device exhausted from the vacuum cleaning device are liquefied and discarded by the condenser and the cooler provided along the exhaust passage of the vacuum pump for the cleaning device. .

  According to the present invention, the low-boiling component and the high-boiling component close to the boiling range of the hydrocarbon-based cleaning liquid can be removed and the cleaning liquid can be regenerated. The cleaning cycle can be maintained without lowering.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in this specification and drawing, the same code | symbol is attached | subjected in the element which has substantially the same function structure.

  FIG. 1 is a block diagram showing an outline of a method for regenerating a cleaning liquid in a vacuum cleaning apparatus according to the present invention.

  In the vacuum cleaning device 2, a cleaning process for the material to be cleaned is performed. The material to be cleaned is carried into the vacuum cleaning apparatus 2 from an entrance door (not shown), and after the entrance door is closed, the cleaning process is started. The cleaning liquid used in the present invention is a naphthenic or paraffinic hydrocarbon cleaning liquid. When the material to be cleaned is cleaned at 40 to 50 ° C., the surface temperature of the material to be cleaned decreases due to the latent heat of vaporization of the cleaning liquid during drying under reduced pressure, and the amount of heat necessary to sufficiently dry the remaining cleaning liquid is insufficient. Therefore, the temperature of the cleaning liquid is set to 90 ° C. or higher, for example, and the material to be cleaned is heated simultaneously with the cleaning. On the other hand, the flash point of the cleaning liquid used in the cleaning process before and after the heat treatment of the metal is about 80 ° C. Therefore, it is necessary to always keep the inside of the vacuum cleaning device 2 in vacuum so that the cleaning liquid does not ignite, and the vacuum cleaning device 2 is evacuated by the cleaning device vacuum pump 9 before the start of the cleaning process.

  In the cleaning process, first, the cleaning liquid in the oil cleaning tank 3 is sprayed onto the material to be cleaned to perform the shower rough cleaning. The cleaning liquid after the rough cleaning is sent to the contaminated liquid tank 4. Next, in order to clean the adhered components of the material to be cleaned that could not be cleaned by rough cleaning, immersion cleaning is performed with the cleaning liquid supplied from the oil cleaning tank 3, and the cleaning liquid after immersion cleaning is returned to the oil cleaning tank 3. It is. Further, the regenerated liquid distilled in the vacuum distillation apparatus 5 is supplied from the regenerated liquid tank 6 to perform shower finishing cleaning, and the cleaning liquid after the final cleaning is returned to the oil cleaning tank 3. Thereafter, the inside of the vacuum cleaning apparatus 2 is evacuated until a preset pressure is reached, and the material to be cleaned to which the cleaning liquid adheres is vacuum dried.

  The oil smoke sucked from the vacuum cleaning device 2 during the vacuum evacuation is collected by the mist trap 13. The components cooled and liquefied in the mist trap 13 are returned to the atmospheric pressure after the vacuum cleaning apparatus 2 is returned to the atmospheric pressure after the material to be cleaned is vacuum dried, and then flowed to the contaminated liquid tank 4. Since the pressures of the mist trap 13 and the contaminated liquid tank 4 are different, it is preferable to provide a cushion tank 19 between the mist trap 13 and the contaminated liquid tank 4 as shown in FIG. The processing of the mist or gaseous component sent from the mist trap 13 to the capacitor 14 will be described later.

  Thereafter, the outlet door (not shown) of the vacuum cleaning device 2 is opened to take out the material to be cleaned, the outlet door is closed, and a series of cleaning steps is completed.

  Hereinafter, the processing of the cleaning liquid by the vacuum distillation apparatus 5 will be described.

  The cleaning liquid is sent from the contaminated liquid tank 4 to the vacuum distillation apparatus 5. As shown in FIG. 2, the vacuum distillation apparatus 5 is provided with a heater 22 on the outer periphery of the lower part of the container 21, and a cooler 23 is provided on the upper part of the container 21. The cleaning liquid that has reached the container 21 from the contaminated liquid tank 4 via the pipe 24 is accumulated as a liquid 25 in the lower part of the container 21 and is heated by the heater 22. The component evaporated by heating is cooled and liquefied by the cooler 23, collected in the receiving tray 26, and then sent from the pipe 27 to the regenerated liquid tank 6 of FIG. And it returns to the oil washing tank 3 from the regeneration liquid tank 6, and is reused as a new washing | cleaning liquid. Alternatively, it is directly injected into the vacuum cleaning device 2 as a cleaning liquid for finishing cleaning. A demister 28 is provided at the boundary between the heater 22 portion and the cooler 23 portion in the container 21 in order to make the fractionation more effective.

  The inside of the vacuum distillation apparatus 5 is evacuated by a distillation apparatus vacuum pump 8. Of the liquid evaporated in the container 21 of FIG. 2, the components that have been liquefied by cooling and not recovered in the regenerated liquid tank 6 become mist or gas and are discharged to the vacuum pump 8 side of the distillation apparatus. . Many of the components that become mist or gas are impurities close to the boiling range of the hydrocarbon-based cleaning liquid.

  When the liquid 25 stored in the lower portion of the container 21 rises to a predetermined temperature, it is sent from the discharge pipe 29 to the waste liquid tank.

  The hydrocarbon-based cleaning liquid used in the present invention is different from the single-component organic cleaning liquid such as IPA or acetone, and usually has a boiling point for each component, not a single component. FIG. 3 shows the boiling points of the low-boiling component and the high-boiling component, which are impurities detected from the hydrocarbon-based cleaning liquid and the cleaning liquid after cleaning, and the boiling range of the hydrocarbon-based cleaning liquid is indicated by a bold line. Low boiling point components such as rust preventive oil partially overlap with the low boiling range part of the hydrocarbon cleaning liquid, and high boiling point metal processing oil overlaps with the high boiling point part of the hydrocarbon cleaning liquid. ing.

  In the vacuum distillation apparatus 5, the high boiling point component is hardly vaporized by controlling the heater 22 so that the temperature of the liquid 25 becomes, for example, the temperature indicated by the one-dot chain line in FIG. 3. It becomes a high boiling point component, that is, an impurity. When heated by the heater 22 for a long time, the temperature rises in a state where the liquid 25 accumulated in the container 21 is boiled. When the temperature of the liquid 25 rises to the boiling range of the metalworking oil shown in FIG. 3, high boiling point components that are not suitable for regeneration as a cleaning liquid will evaporate. Therefore, when the liquid temperature exceeds a predetermined temperature, the waste liquid Send to tank 7.

  A condenser (condenser) 11 is provided on the inlet side of the exhaust passage of the distillation apparatus vacuum pump 8. Of the components of the mist or gaseous cleaning liquid discharged from the vacuum distillation apparatus 5, mainly low boiling point components are liquefied by condensation by the condenser 11 and sent to the waste liquid tank 7. Components that are not liquefied by the condenser 11 pass through the vacuum pump 8 for distillation apparatus.

  An aftercooler 12 is provided on the outlet side of the vacuum pump 8 for the distillation apparatus. Here, the high boiling point component that has passed through the distillation apparatus vacuum pump 8 is cooled and liquefied, and is sent to the waste liquid tank 7. The air that does not contain the component of the cleaning liquid to be liquefied is released into the atmosphere. The components that cannot be fractionated by the vacuum distillation apparatus 5 and flow to the vacuum pump 8 side of the distillation apparatus have many impurities, and they have been collected and reused as cleaning liquids in the past. The impurities contained in the cleaning liquid regenerated by returning to 3 can be reduced. Thereby, it can wash | clean efficiently and can maintain a fixed washing | cleaning cycle.

  When the liquid in the contaminated liquid tank 4 runs out, the cleaning liquid in the oil cleaning tank 3 is sent to the vacuum distillation apparatus 5 and the cleaning liquid is processed in the same process as described above. Thereby, the impurities mixed in the cleaning liquid during the immersion cleaning can be discarded and the distilled cleaning liquid can be reused to keep the cleaning oil in the oil cleaning tank 3 clean.

  Conventionally, the mist-like or gaseous component discharged from the vacuum distillation apparatus 5 is considered to be almost equal to the component recovered by the vacuum distillation apparatus 5, and has been returned to the oil washing tank 3 and reused. . However, as a result of investigating and considering the deterioration of the cleaning liquid in the oil cleaning tank 3, the present inventor has many impurities in the discharged component, unlike the component recovered by the vacuum distillation apparatus 5 and the discharged component. As a result, the present invention has been achieved. As a cause of the difference between the component recovered by the vacuum distillation apparatus 5 and the component discharged, it is considered that the difference in latent heat of solidification has an influence. Due to this difference, impurities are discharged without being recovered by the vacuum distillation apparatus 5, and in the conventional method in which this is reused, the life of the cleaning liquid is short. According to the present invention, it has been confirmed that the life of the cleaning liquid extends several times as compared with the conventional example. Furthermore, it is thought that the cause of the difference in the components removed by the capacitor 11 and the aftercooler 12 is also the difference in solidification latent heat. Therefore, it is necessary to discard both the liquid collected by the condenser 11 and the aftercooler 12.

  Further, the cleaning device vacuum pump 9 for performing vacuum exhaust of the vacuum cleaning device 2 is similarly provided with a condenser 14 on the inlet side of the exhaust passage and an after cooler 15 on the outlet side. Therefore, among the components that have passed through the mist trap 13, mainly low boiling point components are liquefied by the condenser 14 and sent to the waste liquid tank 7. Components that are not liquefied by the condenser 14 pass through the vacuum pump 9 for the cleaning device, and further, high-boiling components are cooled and liquefied mainly by the aftercooler 15 and sent to the waste liquid tank 7. The air that does not contain the component of the cleaning liquid to be liquefied is released into the atmosphere.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to this example. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  The present invention can be applied to a method of regenerating a cleaning liquid by fractionating impurities having a boiling point different from that of the cleaning liquid.

The block diagram which shows the outline of the apparatus which enforces the reproduction | regeneration method of the washing | cleaning liquid concerning this invention. The longitudinal cross-sectional view which shows the outline of a vacuum distillation apparatus. The graph which shows the boiling point of a washing | cleaning liquid and an impurity. The block diagram which shows the outline of the apparatus which enforces the reproduction | regenerating method of the conventional washing | cleaning liquid.

Explanation of symbols

2 Vacuum cleaning device 3 Oil washing tank 4 Contaminated liquid tank 5 Vacuum distillation device 6 Recycled liquid tank 7 Waste liquid tank 8 Vacuum pump for distillation device 9 Vacuum pump for cleaning device 11, 14 Capacitor 12, 15 After cooler 13 Mist trap 19 Cushion tank 21 Container 22 Heater 23 Cooler 24, 27 Piping 25 Liquid 26 Receptacle 28 Demister 29 Discharge pipe

Claims (2)

A method for regenerating a cleaning liquid used in a vacuum cleaning apparatus,
The washing liquid after washing is collected, and the washing liquid component having different boiling points and the impurity component are fractionated by a vacuum distillation apparatus to regenerate the washing liquid component,
The components sucked into the vacuum pump for distillation apparatus exhausted from the vacuum distillation apparatus without being fractionated by the vacuum distillation apparatus are liquefied by a condenser and a cooler provided along the exhaust passage of the vacuum pump. A method for regenerating a cleaning liquid of a vacuum cleaning apparatus, characterized by:   The component sucked into the vacuum pump for cleaning device exhausted from the vacuum cleaning device is liquefied by a condenser and a cooler provided along the exhaust passage of the vacuum pump for cleaning device and discarded. A method for regenerating a cleaning liquid in a vacuum cleaning apparatus according to claim 1.

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