JP6934257B2 - How to prevent the diffusion of the cleaning solvent in the cleaning tank into the atmosphere - Google Patents

Description

The present invention relates to a method for preventing the cleaning solvent in the cleaning tank from diffusing into the atmosphere when cleaning objects to be cleaned such as mechanical parts, electronic parts, and medical devices with a cleaning solvent.

Japanese Patent Application Laid-Open No. 60-45922 Since 1995, when cleaning objects to be cleaned such as mechanical parts, electronic parts, medical equipment, etc. with liquid cleaning and / or steam cleaning, the inner surface of the cleaning tank (103) is used as shown in FIG. Cooled water or refrigerant gas is passed through the provided cooling pipe (105), and the solvent vapor (102) of the cleaning solvent stored inside the cleaning tank (103) is condensed on the surface of the cooling pipe (105). As a result, it is common practice to suppress the diffusion of the solvent vapor in the cleaning tank (103) into the atmosphere.

Further, as shown in Patent Document 1, a cooled cleaning solvent is allowed to flow down in the cleaning tank to form a liquid curtain, and the solvent vapor is brought into contact with the liquid curtain to bring the solvent of the cleaning solvent stored in the cleaning tank into contact with the solvent. A method of condensing the vapor and suppressing the diffusion of the solvent vapor into the atmosphere is already known.

However, since 1995, when the above-mentioned conventional method was generally performed, chlorofluorocarbon, which has been widely used as the above-mentioned cleaning solvent, has been completely abolished worldwide as a substance that destroys the ozone layer. From this time on, the standards for using cleaning solvents have become even stricter in order to protect the global environment even at cleaning sites. Therefore, it has been difficult for the above-mentioned method for condensing and recovering solvent vapor to comply with such strict regulations regarding prevention of diffusion of solvent vapor into the atmosphere.

Therefore, in order to comply with such strict regulations, it is conceivable to further cool the cooling pipe to remarkably lower the temperature in the cleaning tank and keep the temperature of the cooling portion in the cleaning tank low. However, when the temperature of the cooling pipe (105) of the above-mentioned conventional example is set to 0 ° C. or lower, the moisture in the atmosphere adhering to the cooling pipe (105) becomes ice, so that the entire surface of the cooling pipe (105) is covered. Ice may adhere to the cleaning tank and reduce the cooling efficiency.

Further, as shown in Patent Document 1, when a liquid curtain is formed, when the temperature of the liquid curtain is 0 ° C. or higher, moisture in the atmosphere is mixed in the cleaning solvent, especially in the case of a chlorine-based solvent or the like. Since hydrolysis occurs in the cleaning solvent, it is difficult to condense and reliably recover the cleaning solvent.

Therefore, the present application is intended to solve the above-mentioned problems, and is intended to easily prevent the diffusion of solvent vapor into the atmosphere by a simple method.

In order to solve the above-mentioned problems, the present invention stores the cleaning solvent in the cleaning tank, and in a cooling tank provided separately from the cleaning tank, the cleaning solvent is kept at 0 ° C. or lower and the freezing point of the cleaning solvent. By cooling to a higher temperature and letting the cooled cleaning solvent flow down into the cleaning tank, a liquid curtain is formed even during steam cleaning of the object to be cleaned, and the temperature inside the cleaning tank is lowered, and this liquid is also used. The solvent vapor is condensed by bringing the solvent vapor of the cleaning solvent in the cleaning tank into contact with the curtain.

The cleaning tank, the cooling mechanism of the upper lower two stages in its inner portion is provided, the upper cooling mechanism, for by flowing down the cooled wash solvent was forming a liquid curtain, a nozzle in communication with the cooling tank In addition to being provided, the lower cooling mechanism may be provided with a cooling pipe for cooling the washing steam.

Further, the cleaning solvent in the cleaning tank and the cleaning solvent in the cooling tank may be the same.

Further, the solvent vapor is condensed by bringing the solvent vapor of the cleaning solvent stored in the cleaning tank into contact with the liquid curtain, and the water content in the solvent vapor is recovered as ice to form a condensed cleaning solvent. It may be separated. In this way, since the water content in the solvent vapor can be recovered as ice, it is possible to easily separate the solid water content and the liquid cleaning solvent, and the cleaning solvent contains water content. It can be reused without it. In addition, since it is possible to prevent a situation in which the cleaning solvent is hydrolyzed and deteriorated due to the mixing of water, the cleaning solvent can be reused by a simple method.

Further, the cleaning solvent in the cooling tank may be set to any temperature as long as it is 0 ° C. or lower and the temperature is higher than the freezing point of the cleaning solvent.

Since the present invention is configured as described above, the solvent vapor can be brought into the atmosphere by a simple method of bringing the solvent vapor into contact with a liquid curtain cooled to 0 ° C. or lower and a temperature higher than the freezing point of the cleaning solvent. The effect of preventing diffusion can be further enhanced.

The conceptual diagram of Example 1 which shows the invention of this application. The conceptual diagram of Example 2 which shows the invention of this application. Conceptual diagram of a conventional example.

When the first embodiment of the present invention will be described with reference to FIG. 1, (1) is a cleaning tank, and a coolant pipe (3) is provided on the inner circumference of the cleaning tank (1) on the opening (2) side. A nozzle (4) is provided. The cooling liquid pipe (3) communicates with the bottom side of the cooling tank (5) provided separately from the cleaning tank (1) via the pump (6). Further, below the nozzle (4), a condensate recovery tray (7) is provided along the inner surface of the cleaning tank (1). Further, at the bottom of the cleaning tank (1), a heater (10) for heating the cleaning solvent (8) stored inside and a temperature sensor (11) for controlling the temperature of the cleaning solvent (8) are provided. ing.

Further, the cooling tank (5) internally stores the same cleaning solvent (8) as that stored in the cleaning tank (1), and is above the liquid level (12) of the cleaning solvent (8). Is provided with a mesh-shaped ice receiving tray (13). Then, one end of the recovery pipe (14) for collecting the recovered condensate is arranged in the recovery tray (7) provided in the cleaning tank (1), and the other end of the recovery pipe (14) is placed on the recovery pipe (14). It is placed facing the ice tray (13). Further, on the bottom side of the cooling tank (5), a cooler (16) for cooling the cleaning solvent (8) stored in the cooling tank (5) is provided.

Further, an overflow pipe (15) of the cleaning solvent (8) that can flow from the central portion of the cooling tank (5) in the depth direction toward the bottom side of the cleaning tank (1) is provided. That is, one end of the overflow pipe (15) is connected to the central portion in the depth direction of the cooling tank (5), and the other end is connected to the bottom side of the cleaning tank (1). As a result, the cleaning solvent (8) recovered in the cooling tank (5) is kept at a constant amount, and the cleaning solvent (8) exceeding this constant amount can be refluxed into the cleaning tank (1).

The method of cleaning the object to be cleaned in the above-described structure will be described below. First, by operating the heater (10) in the cleaning tank (1) to heat the cleaning solvent (8), the solvent vapor (17) of the cleaning solvent (8) is generated in the cleaning tank (1). .. As a result, the solvent vapor (17) rises toward the opening (2) of the cleaning tank (1). Therefore, by arranging the object to be cleaned (18) in the solvent vapor (17) as shown in FIG. 1, the object to be cleaned (18) can be steam-cleaned.

The cleaning solvent (8) used in this embodiment is widely and generally used, and is, for example, trichlorethylene, tetrachlorethylene, ethanol, dichloromethane, HFО and the like.

In addition, the same cleaning solvent (8) as the cleaning solvent (8) in the cleaning tank (1) is stored in the cooling tank (5) in advance, and the cooling device (16) is operated to perform this cleaning. The solvent (8) is cooled to 0 ° C. or lower and a temperature higher than the freezing point of the cleaning solvent (8). Then, the cleaning solvent (8) cooled in the cooling tank (5) is transferred to the nozzle (4) arranged in the cleaning tank (1).

Then, the cleaning solvent (8) cooled from the nozzle (4) is continuously flowed down to form the liquid curtain (20). By forming the liquid curtain (20) of the cleaning solvent (8) cooled in this way, the solvent vapor (17) rising in the cleaning tank (1) comes into contact with the liquid curtain (20). Therefore, the solvent vapor (17) in contact with the liquid curtain (20) is condensed and collected in the recovery tray (7). This makes it possible to enhance the effect of preventing the solvent vapor (17) from diffusing into the atmosphere. Further, since this liquid curtain (20) is formed by the cleaning solvent (8) continuously supplied from the cooling tank (5) and cooled to 0 ° C. or lower and above the freezing point of the cleaning solvent (8). The cooling effect of the solvent vapor (17) can be maintained in good condition continuously without being deteriorated.

Then, the cleaning solvent (8) recovered in the recovery tray (7) as described above is stored in the cooling tank (5) again through the recovery pipe (14). At this time, since the temperature of the liquid curtain (20) is 0 ° C. or lower, the solvent vapor (17) in contact with the liquid curtain (20) is cooled to 0 ° C. or lower. Therefore, the water contained in the condensed cleaning solvent (8) becomes ice particles depending on the cooling state and is recovered in the recovery tray (7).

Therefore, the ice in the cleaning solvent (8) stored in the cooling tank (5) from the recovery pipe (14) is collected in the ice receiving tray (13), and the cleaning solvent (8) is a mesh-shaped ice receiving tray. It passes through the tray (13) and is stored in the cooling tank (5). In this case, not all of the solvent vapor (17) becomes ice particles by the above cooling, but then becomes ice in the cooling tank (5) and floats in the cleaning solvent (8) in the cleaning tank (5). Sometimes. In this way, the contact with the liquid curtain (20) does not interfere with the transmission of the cooling temperature by the moisture in the atmosphere, and the moisture can be easily recovered.

Although in this and the following examples are described with the steam washing is not limited thereto in other embodiments, the cleaning tank (1) (31) in a object to be cleaned (18) (55 ), Similarly, by using the liquid curtain (20) and the cooling pipe (44) below to keep the inside of the cleaning tanks (1) and (31) at 0 ° C or lower, the cleaning tanks (1) and (31) While suppressing the generation of solvent vapors (17) (54) from the cleaning solvents (8) (40) inside, even if solvent vapors (17) (54) are generated, the amount will be small, so this is used as a liquid curtain. By condensing in (20) and (50), the cleaning solvents (8) and (40) stored in the cleaning tanks (1) and (31) become solvent vapors (17) and (54) and enter the atmosphere. It can be effectively prevented from spreading.

In Example 2 of the present invention, a two-stage upper and lower cooling mechanism (57) (58) is provided inside the cleaning tank, and a cooled cleaning solvent (40) is allowed to flow down the upper cooling mechanism (57). A nozzle (36) communicating with the above cooling tank is provided to form the liquid curtain (50), and a cooling pipe (44) for cooling the solvent steam (54) is provided in the lower cooling mechanism (58). Is provided.

Explaining this embodiment in FIG. 2, (31) is a cleaning tank, and the bottom of the cleaning tank (31) has a heater (32) for heating the cleaning solvent (40) stored inside. ), And a temperature sensor (33) that controls the temperature of the cleaning solvent (40) is provided. Explaining the upper cooling mechanism (57), as in the first embodiment, the nozzle (36) of the cooling liquid pipe (35) is provided on the inner circumference on the opening (34) side, and the cooling liquid pipe is provided. (35) communicates with the bottom side of the first cooling tank (37) provided separately from the cleaning tank (31) via the pump (38). Further, below the nozzle (36), a first recovery tray (41) for recovering the cleaning solvent (40) condensed along the inner surface of the cleaning tank (31) is provided.

Further, the first cooling tank (37) has the same configuration as that of the first embodiment, and contains the same cleaning solvent (40) as that stored in the cleaning tank (31), and also contains an ice tray (ice receiving tray). 42) is provided. Then, one end of the first recovery pipe (43) is arranged in the first recovery tray (41) of the washing tank (31), and the other end of the first recovery pipe (43) is the ice receiving tray (42). ) Is placed facing it.

Next, the lower cooling mechanism (58) will be described. A cooling pipe (44) is provided below the first recovery tray (41), and a second recovery tray (44) is provided below the cooling pipe (44). 45) is provided. Then, one end of the supply pipe (46) and one end of the discharge pipe (47) are connected to the cooling pipe (44), and the other ends of the supply pipe (46) and the discharge pipe (47) are cleaned. It is connected to a second cooling tank (48) provided separately from the tank (31). The second cooling tank (48) contains the same cleaning solvent (40) as the cleaning solvent (40) in the cleaning tank (31), and cools the cleaning solvent (40).

By providing the cooling pipe (44) on the inner circumference of the cleaning tank (31) in this way, the temperature inside the cleaning tank (31) can be lowered, so that the cleaning solvent (40) forming the liquid curtain (50) is formed. ) Can reduce the amount of heat required for cooling. Further, one end of the second recovery pipe (51) is connected to the second recovery tray (45), and the other end of the second recovery pipe (51) is provided on the outside of the cleaning tank (31). It is connected to the moisture separator (52). One end of the perfusion tube (53) is connected to the bottom of the water separator (52), and the other end of the perfusion tube (53) is connected to the bottom side of the cleaning tank (31).

The cleaning method of the object to be cleaned (55) in the above-described structure will be described below. First, by operating the heater (32) in the cleaning tank (31) to heat the cleaning solvent (40), the solvent vapor (54) of the cleaning solvent (40) is generated in the cleaning tank (31). .. As a result, the solvent vapor (54) of the cleaning solvent (40) rises toward the opening (34) of the cleaning tank (31). Therefore, by arranging the object to be cleaned (55) in the solvent steam (54), the object to be cleaned (55) can be steam-cleaned.

The cleaning solvent (40) used in this embodiment is widely and generally used, and is, for example, trichlorethylene, tetrachlorethylene, ethanol, dichloromethane, HFО and the like.

Further, the cleaning solvent (40) in the first cooling tank (37) is cooled in advance by the cooler (56) to a temperature of 0 ° C. or lower and higher than the freezing point of the cleaning solvent (40). Then, by operating the pump provided in the coolant pipe (35), the cleaning solvent (40) cooled in the first cooling tank (37) as described above is arranged in the cleaning tank (31). The liquid curtain (50) is transferred to 36), and the cleaning solvent (40) cooled in the first cooling tank (37) is continuously flowed down from the nozzle (36) constituting the upper cooling mechanism (57). To form.

By forming the liquid curtain (50) of the cleaning solvent (40) cooled in this way, the solvent vapor (54) rising in the cleaning tank (31) comes into contact with the liquid curtain (50). Therefore, the solvent vapor (54) that has come into contact with the liquid curtain (50) is condensed and recovered in the first recovery tray (41). As a result, the effect of preventing the solvent vapor (54) from diffusing into the atmosphere can be further enhanced.

Then, the cleaning solvent (40) recovered in the first recovery tray (41) is recovered in the first cooling tank (37) through the first recovery pipe (43). At this time, since the temperature of the liquid curtain (50) is 0 ° C. or lower, the water contained in the cleaning solvent (40) is recovered as ice particles. Therefore, the ice in the cleaning solvent (40) discharged from the first recovery pipe (43) is collected in the ice receiving tray (42), and the cleaning solvent (40) is collected in the mesh-shaped ice receiving tray (42). ) And be stored in the first cooling tank (37).

As described above, since the water contained in the solvent vapor (54) becomes ice particles when it comes into contact with the liquid curtain (50), the water in the cleaning solvent (40) can be easily recovered and condensed. The cleaning solvent (40) that has been treated can be recovered in a state that does not contain water. Therefore, the recovered cleaning solvent (40) can be reused without the need for performing the water separation work, so that it is not necessary to prepare a separate water separator (52) and perform the water separation work. It can be reused by a simple method. In addition, it is possible to prevent the cleaning solvent (40) from being hydrolyzed and deteriorated due to the mixing of water.

At the same time as the formation of the liquid curtain (50), the cooling pipe (44) constituting the lower cooling mechanism (58) in the cleaning tank (31) is also passed from the second cooling tank (48) through the supply pipe (46). The cooled cleaning solvent (40) is circulated in the cooling pipe (44). As a result, when the solvent vapor (54) is started up in the cleaning tank (31), the solvent vapor (54) comes into contact with the cooling pipe (44), and the solvent vapor (54) can be condensed. Further, by providing the cooling pipe (44) on the inner circumference of the cleaning tank (31) in this way, the temperature inside the cleaning tank (31) can be lowered, so that the cleaning solvent (50) forming the liquid curtain (50) is formed. 40) The amount of heat required for cooling can be kept low.

Further, the condensate condensed in contact with the cooling pipe (44) in this way is collected in the second recovery tray (45) and then transferred into the water separator (52) through the second recovery pipe (51). Will be done. Then, the moisture in the condensate and the cleaning solvent (40) are separated by this moisture separator (52), and the separated cleaning solvent (40) is put into the cleaning tank (31) again through the reflux pipe (53). Reflux.

1,31 Washing tank
8,41 Cleaning solvent
17,54 Solvent vapor
20,50 Liquid curtain
44 Cooling pipe
57,58 Cooling mechanism

Claims (5)

The cleaning solvent is stored in the cleaning tank, and the cleaning solvent is cooled to 0 ° C. or lower and higher than the freezing point of the cleaning solvent in a cooling tank provided separately from the cleaning tank, and the cooled cleaning is performed. By flowing the solvent into the cleaning tank, a liquid curtain is formed even during steam cleaning of the object to be cleaned to lower the temperature in the cleaning tank, and the solvent vapor of the cleaning solvent in the cleaning tank is applied to the liquid curtain. A method for preventing the diffusion of the cleaning solvent in the cleaning tank into the atmosphere, which comprises condensing the solvent vapor by bringing them into contact with each other. The cleaning tank, the cooling mechanism of the upper lower two stages in its inner portion is provided, the upper cooling mechanism, for by flowing down the cooled wash solvent was forming a liquid curtain, a nozzle in communication with the cooling tank The method for preventing diffusion of the cleaning solvent in the cleaning tank into the atmosphere according to claim 1, wherein a cooling tube for cooling the cleaning steam is provided in the lower cooling mechanism. The method for preventing diffusion of the cleaning solvent in the cleaning tank into the atmosphere according to claim 1 or 2, wherein the cleaning solvent in the cleaning tank and the cleaning solvent in the cooling tank are the same. The solvent vapor of the cleaning solvent stored in the cleaning tank is brought into contact with the liquid curtain to condense the solvent vapor, and the moisture in the solvent vapor is recovered as ice and separated from the condensed cleaning solvent. The method for preventing the diffusion of the cleaning solvent in the purification tank into the atmosphere according to claim 1 or 2. The cleaning solvent in the cooling tank can be set to an arbitrary temperature as long as it is 0 ° C. or lower and higher than the freezing point of the cleaning solvent. How to prevent the diffusion of the cleaning solvent into the atmosphere.

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