JPH0425214Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is an improved invention of Utility Model Registration Application No. 50180 of 1988 filed on April 14, 1988, and is particularly applicable to the metal cleaning process. 1,1,2-trichlor-1, which is used in electronic parts cleaning processes, etc.
This is a solvent vapor recovery device effective for recovering vaporized vapor of 2,2-trifluoroethane.

(Prior Art) Cleaning tanks that store organic solvents as cleaning liquids have a problem in that, because these cleaning liquids are volatile, solvent vapor is released into the atmosphere and pollutes the environment.

In particular, freons such as 1,1,2-trichloro-1,2,2-trifluoroethane are highly stable and require severe treatment because their vapors may accumulate in the stratosphere and destroy ozone. As regulations are likely to be enforced, countermeasures have become necessary.

For example, printed circuit boards for integrated circuits (hereinafter referred to as ICs) must be cleaned with an organic solvent such as Freon, as poor contact will occur if the flux used for soldering is not removed. However, since this IC printed circuit board already has a greased volume knob soldered to it, it cannot be immersed in a cleaning tank, and only the back side of the board must be cleaned by contact. For this purpose, a transport device for transporting and lowering the substrate is installed above the cleaning tank in the direction of the central axis. Therefore, the cleaning tank is of an open-top type, and the dispersion of solvent vapor into the atmosphere cannot be avoided.

Of course, measures have been taken in conventional cleaning tanks, such as installing cooling pipes in the vapor zone, guiding overflowing and sinking solvent vapor to a gutter to condense it, and increasing the height of the freeboard. , none of them were perfect.

For this reason, consideration has been given to disposing of conventional equipment, converting the entire cleaning tank into a closed system, and considering transportation methods for items that cannot be closed, but all of these methods are expensive and reduce cleaning work efficiency. The problem is that sacrifices must be made.

On the other hand, other recovery devices talk about the recovery efficiency of the device without considering the collection efficiency, resulting in a recovery device with a large processing air volume. However, the recovery rate is the amount of recovered liquid/
Since the amount of fluorocarbon evaporation and the amount of molecular recovery liquid should be determined by the amount of transpiration x collection efficiency x device performance, it is important where the processing gas is collected. For example, in some conventional recovery devices, the location of the duct for inhaling solvent vapor is fixed within the cleaning tank. However, the vapor zone at the top of the cleaning tank is
The concentrations are extremely different, such as 200ppm, 1000ppm, 3000ppm, and 500000ppm. Therefore,
If the duct for inhaling the solvent is not placed at the desired position and the vapor is collected and treated at an unnecessarily high concentration, the efficiency will be poor.

Also, since the upper part of the cleaning tank is wide in length and width,
The intake port of the duct will also be longer. However, since the duct is connected to the suction blower by a pipe, the air volume at the suction port near the suction pipe is large, but the air volume at the suction port far from the suction pipe is extremely low, which is a drawback. .

Furthermore, the overall air volume can be easily adjusted.
It is desirable that the device be compact and take up less space.

(Problems to be solved by the invention) In view of the above-mentioned circumstances, the present invention utilizes conventional cleaning tank equipment as is, efficiently collects solvent vapor, and creates a small, inexpensive, and versatile system. The purpose is to provide collection equipment.

Moreover, the duct is arranged at a desired optimal position, for example, at the edge of the upper surface of the cleaning tank, so that overflowing vapor can be collected, so that the suction air volume does not become uneven depending on the location. A secondary object of the present invention is to provide a compact solvent vapor recovery device that does not take up much space and allows the overall air volume to be easily adjusted using, for example, a slit type.

(Means for solving the problem) The present invention provides a duct for inhaling solvent vapor at a desired position above the cleaning tank that stores the organic solvent.
A suction blower and an activated carbon adsorption tower are directly connected to the duct, and one end of the activated carbon adsorption tower is equipped with steam and the other end is equipped with a condenser so that the solvent vapor can be recovered in liquid form. The above problems were solved by providing an adjustment plate that can adjust the air volume and a partition plate with suction holes.

In addition, the present invention uses 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113) as an organic solvent. A preferred embodiment is that the towers are directly connected in series.

(Function) The adjustment plate is used to easily adjust the amount of air taken into the duct.The adjustment plate is a groove that is attached to the duct with bolts and nuts so that the slit of the intake port can be made wider or narrower. A slit duct suction system having a long groove and adjustable slit width is preferred.

In addition, since a long duct is connected to a suction blower by a suction pipe from one point, uneven air volume due to distance from the suction pipe can be solved by installing a partition plate to shield the inside of the duct. By drilling suction holes of appropriate spacing and size,
This allows suction with a uniform amount of air from any position.

Furthermore, since the recovery device of the present invention is installed around a regulated cleaning tank, it is often limited by the floor space within the factory. The first objective was to make the recovery device compact, and the two activated carbon adsorption towers for adsorption and desorption were generally arranged side by side. It is also preferable to build this into a two-story building with two towers one above the other to make it even more compact.

Since fluorocarbon vapor has a weight 6.5 times that of air, it tends to sink, and it is also desirable to collect the fluorocarbon vapor that overflows from the top of the cleaning tank using the bottom air volume at the edge of the top of the cleaning tank.

(Example) Hereinafter, an example of the present invention will be described using the drawings.

FIG. 1 is a schematic vertical sectional view showing an embodiment of the device of the present invention attached to a cleaning tank, and FIG. 2 is a plan view of the same.
FIG. 3 is a perspective view showing an embodiment of the device of the present invention;
FIG. 4 is a perspective view showing the adjuster plate in the device;
Fig. 5 is a perspective view showing a partition plate in the device, Fig. 6 is a flow sheet showing an embodiment of the device of the present invention, and Fig. 7 1 is a device of the present invention with a processing air volume of 5 m ³ /min. 7 is a longitudinal sectional view seen from the front, and FIG. 72 is a longitudinal sectional view seen from the same side.

First, in FIGS. 1 and 2, the organic solvent 1 used in this example is Freon-113 (C ₂ Cl ₃ F ₃ ), that is, 1,1,2-trichloro-1,2,2-trifluoro. Ethane, boiling point 47.57°C, was used. Of course, it is also possible to use a mixture of, for example, 96% Freon-113 and 4% ethanol (ethyl alcohol) having a boiling point of 78.3°C to lower the azeotropic point to about 44°C.

2 is a cleaning tank that stores the organic solvent used in metal cleaning processes and electronic parts cleaning processes.
The top surface of the cleaning tank 2 has no lid and is open.
The cleaning tank 2 is of an open top type. In this system, a transfer device 4 consisting of a conveyor for transferring and lowering an object 3 to be cleaned such as an IC board is connected to a transfer tank 2.
Since the cleaning tank 2 is installed in the central axis direction, it is not possible to cover the top surface of the cleaning tank 2.

This cleaning tank 2 is actually divided into several parts, such as a hot bath cleaning tank and an ultrasonic cleaning tank, but the temperature of the hot bath cleaning tank is maintained at around 40°C to enhance the cleaning effect. Therefore, the surface of the organic solvent 1 liquid is covered with a vapor zone 5 formed by vaporized solvent. This vapor zone 5 is precisely a steam tank and a gas layer, and even if the object to be cleaned 3 is not immersed in the organic solvent 1, if it is brought into contact with this vapor layer or gas layer, it will remove dirt such as flux. The solvent vapors must be removed. However, if this barper zone 5 is completely removed,
The presence of the vapor zone 5 is also necessary because of the occurrence of wash spots.

Reference numeral 6 denotes a cooling pipe installed below a freeboard surrounding the peripheral side of the cleaning layer 1, and is provided to liquefy solvent vapor. However, the cooling pipe 6 does not actively suck in solvent vapor, and can only be installed below the vapor zone 5 where it does not draw in moisture from the outside air.

Therefore, in the present invention, the ducts for inhaling the solvent vapor are arranged around the entire circumference of the upper surface 7 of the cleaning tank 2, for example, 8a, 8b, 8c, 8d, 8e,
Place it like 8f. 8a and 8b are 8 in the width direction.
c and 8d are connected and 8e and 8 are connected in one length direction.
f are connected and arranged in the length direction of the other to suck in the solvent vapor 9 overflowing from the upper surface 7 of the cleaning tank 2. In the case of Fig. 2, the ducts 8a, 8b, 8
8c, 8e, and 8f are shown, and the solvent vapor 9, conveyance device 4, etc. are omitted.

However, the duct for inhaling solvent vapor of the present invention is
The cleaning layer 2 may be attached to an inner wall of a suitable height of a freeboard surrounding the peripheral side of the cleaning layer 2, and the ducts 8g and 8h shown by dotted lines in FIG. 1 are examples of this. In this way, the ducts 8a to 8h of the present invention are
The reason why it is placed at a desired position above the cleaning tank is because the concentration of the vapor zone at the top of the cleaning tank is extremely different depending on the height. For example, if the vapor zone concentration on the top surface is 200 ppm, 10 m/m
At the position lowered into cleaning tank 2, the concentration is 1000ppm, and 20
Since the concentration rises to 3000ppm at a position below 30m/m and 500000ppm at a position below 30m/m, it is necessary to install it at a location where the concentration is low enough to prevent overflow. It is important to select this desired height, since this would impair the recovery system of the device.

Next, in FIGS. 3 to 5, an example of the duct 8 used in the device of the present invention is a width of 70 mm,
There is a suction inlet at the lower part of the front of the rectangular square pipe with a height of 100 mm and a length of about 1000 mm. Connect at one end or the center.

At the entrance of the duct 8, an adjuster plate 11 as shown in FIG. 4 is provided which can adjust the overall air volume.
The adjuster plate 11 can be moved up and down by longitudinal grooves 12 . . . 12 to adjust the slit width 13 at the entrance. The inside of the duct 8 is obstructed in an inclined manner by a partition plate 14, and suction holes 15a...15i are formed in the partition plate 14 in the length direction.
Therefore, the solvent vapor sucked through the slit width 13 is not blown to the outlet pipe 10 unless it passes through the suction holes 15a...15i. Therefore, the air volume in the suction hole 15a near the outlet pipe 10 does not increase, the air volume in the suction hole 15i farther from the exit pipe 10 does not decrease, and the air volume can be distributed almost uniformly.

Next, the configuration of the collection device will be explained using the flow sheet shown in FIG.

The recovery system of the present invention uses a fixed-bed granular activated carbon adsorption method and a two-column continuous operation as standard, and one cycle of each column consists of an adsorption process, a desorption process, and a drying process.

The solvent vapor processing gas sucked into the duct is
Suction blower 17 via air filter 16
is attracted by. Other recovery devices have a processing air volume of 100
m ³ /min, 200m ³ /min, and a large suction blower is used to accommodate this, but the recovery device of this invention has a processing air volume of 3.
m ³ /min, 5m ³ /min small suction blower 17
is adopted. This suction blower 17 has No.
No. 1 activated carbon adsorption tower 18a and No. 2 activated carbon adsorption tower 1
It is directly connected to 8b. One activated carbon adsorption tower 18a
Alternatively, when 18b adsorbs the process gas and discharges clean air into the atmosphere, the other activated carbon adsorption tower 18b or 18a desorbs the gas, and normally No. 1 and No. 2 activated carbon adsorption towers are Although they are arranged horizontally, the recovery device of the present invention can be made more compact by stacking two towers vertically, that is, directly connecting the No. 1 activated carbon adsorption tower 18a in tandem with the No. 2 activated carbon adsorption tower 18b. There used to be. This reduces the installation area and is a new configuration that has never been seen before.

In the activated carbon adsorption towers 18a and 18b, 4 to
It is filled with 6 meshes of granular activated carbon, but activated carbon with a fibrous or honeycomb structure can also be used. One end of the activated carbon adsorption towers 18a, 18b is piped so that steam 19 can be introduced, and a condenser 20 is attached to the other end, so that adsorption automatically shifts to a desorption step at a predetermined time. A spiral coil (not shown) installed in the condenser 20 is circulated and cooled by cooling water 21 from the surrounding area so that the solvent vapor to be treated can be liquefied.

A water separator 21 is connected to the condenser 20, and a storage tank 22 is connected to the water separator 21.
are connected so that the solvent vapor can be recovered in liquid form, but the capacity of the condenser is preferably redundant. Next, the operating procedure of the solvent vapor recovery apparatus of the present invention having the above configuration will be described in detail.

The solvent vapor sucked through the duct by the suction blower 17 passes through the activated carbon layer of the No. 1 adsorption tower 18a, is adsorbed, and is exhausted into the atmosphere as clean air 23. At this time, first the No. 2 adsorption tower 1
The solvent vapor adsorbed by 8b is desorbed by introducing steam 19 to heat the activated carbon, is transported by the water vapor, enters the condenser 20, and is condensed and liquefied by the cooling water 21. Since the liquefied solvent completely liquefied by the condenser 20 also contains moisture due to steam etc., the oil and water are completely separated by the water separator 21 and transferred to the storage tank 2.
2, it is stored and recycled. Note that after the desorption process, the activated carbon is dried and cooled by the room air 20, and then moves to the adsorption process again.

For example, when the processing air volume is 5 m ³ /min, the adsorption time depends on the Freon concentration. Kg/h 2 hours 500ppm 1.2Kg/h About 4 hours, the desorption process takes about 10 minutes, and the drying and cooling process takes about 15 minutes. The device of the present invention can recover at least 95% or more of the amount of solvent in the intake air, and by selecting good conditions and operating properly, it is possible to recover 99.8%.

The adjusting plate and the partition plate in the above embodiment are merely examples; in short, the adjusting plate provided in the duct of the present invention is of a mechanism that can adjust the overall air volume, and the partition plate is Any material may be used as long as it serves as a shielding plate with suction holes (of any shape).

The following Figures 7 1 and 7 2 show the arrangement of each mechanism of an actual device with a processing air volume of 5 m ³ /min according to the present invention.
a, 8b, condenser 20, water separator 21, storage tank 22, etc. are compactly housed.

(Effects of the idea) Freon, which has been brought up as an environmental issue due to stratospheric ozone depletion, has been found to have a substitute for Freon 11, but there is no substitute for Freon 113, so a recovery device is desired. The device of the present invention can meet that need.

By incorporating the device of this invention, there is no need to dispose of the conventional cleaning tank and install an expensive new one.
The conventional cleaning tank can be used as is, and there is no need for a sealed system surrounding the cleaning tank, so it can be solved with inexpensive modification.For example, a closed system with 20
If a recovery device with a capacity of 5 m ³ /min is required, the system of the present invention can achieve similar recovery efficiency with a device with a capacity of 5 m ³ /min.

The device of the present invention achieves thorough compactness with a small collection device through effective collection.
Stacking activated carbon adsorption towers one above the other also contributes to a reduction in floor space.

Solvent recovery efficiency is determined not only by equipment efficiency but also by collection efficiency. Other recovery machines are installed above the liquid level of the washer and process high-concentration vapor that does not need to be sucked up, reducing recovery efficiency. For example, in the case of other recovery machines, 9 kg of CFCs are collected per day.
It is said that CFC 113 can be recovered, but for that purpose CFC 113
If you say that you will put in 16 kg of water per day, then 7 kg per day.
This means that CFC-113 is diffused into the atmosphere.
In this respect, if you switch to the recovery device of this invention, you will be able to
113 collection is limited to 3.5 kg per day, but in this case,
We only need to use less than 4kg of Freon 113 per day.
This is because the collection duct that guides the collection device of the present invention is not installed at the high concentration vapor zone above the liquid level of the washer, but rather collects vapor at the bottom where vapor overflows from the upper groove of the cleaning tank. This is because by finely adjusting and arranging the collection device at a desired optimum position above the cleaning tank, the collection efficiency can be increased with a small collection device.

In addition, an adjuster plate is attached to the collection duct of the collection device of the present invention, and the interval between the slits in the suction port can be adjusted, and the overall air volume can be easily adjusted as in Utility Model Registration Application No. 50180 of 1988. It allows you to select the optimal air volume.

Furthermore, a partition plate is attached to the duct of the recovery device of the present invention, and the suction holes bored in this partition plate can be placed close to the suction pipe by adjusting the size of the holes as appropriate, for example, at intervals of 10 mm or 50 mm. They are arranged in distant groups to ensure uniform suction from all positions.

The arrangement of the duct in the desired position, the adjusting plate, and the partition plate of the present invention do not necessarily have to meet the three requirements, but by combining one or two of them, the same effect as the present invention can be achieved. Of course you can get it.

With the recovery device of the present invention, there is no need to raise the free board at the top of the cleaning tank, there is no need to seal the top of the cleaning tank, and there is no problem with workability.
In particular, it can be installed not only in automatic washing machines but also in manual washing machines in a position that does not easily interfere with the cleaning work, making it possible to achieve high collection efficiency.

The recovery device of the present invention can completely prevent overflow of solvent vapor, enable recovery and reuse, and maintain excellent quality of the items to be cleaned, among other benefits. A useful and practical solvent vapor recovery device is provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view showing an embodiment of the device of the present invention attached to a cleaning tank, and FIG. 2 is a plan view of the same.
FIG. 3 is a perspective view showing an embodiment of the device of the present invention;
FIG. 4 is a perspective view showing the adjuster plate in the device;
Fig. 5 is a perspective view showing a partition plate in the device, Fig. 6 is a flow sheet showing an embodiment of the device of the present invention, and Fig. 7 1 is a device of the present invention with a processing air volume of 5 m ³ /min. 7 is a longitudinal sectional view seen from the front, and FIG. 72 is a longitudinal sectional view seen from the same side. In the figure, 1...Organic solvent, 2...Cleaning tank, 8,8
a, 8b, 8c, 8d, 8e, 8f, 8g, 8h
... Duct, 9 ... Solvent vapor, 11 ... Adjustment plate, 14 ... Partition plate, 15a to 15i ... Suction hole, 17 ... Suction blower, 18a, 18b ...
Activated carbon adsorption tower, 19...Steam, 20...Condenser, O...Open.

Claims (1)

[Claims for Utility Model Registration] 1. A duct for inhaling solvent vapor is provided at a desired position above a cleaning tank that stores organic solvents, a suction blower and an activated carbon adsorption tower are directly connected to the duct, and the activated carbon adsorption tower is directly connected to the duct. Steam is attached to one end of the tower and a condenser is attached to the other end so that the solvent vapor can be recovered as a liquid, and the duct is equipped with an adjuster that can change the width of the slit at the inlet through which the solvent vapor is sucked into the duct. 1. A solvent vapor recovery device comprising: a plate; and a partition plate having a suction hole through which solvent vapor sucked from the inlet passes. 2 The organic solvent is 1,12-trichloro-1,2,
The solvent vapor recovery device according to claim 1, characterized in that the solvent vapor is 2-trifluoroethane. 3. The solvent vapor recovery device according to claim 1, wherein the cleaning tank is of an open-top type. 4 Utility model registration claim 1 characterized in that two activated carbon adsorption towers are directly connected in series, one above the other.
Solvent vapor recovery device as described in Section 1.