JP4745086B2 - Painting booth using circulating treatment liquid - Google Patents

Description

The present invention relates to an apparatus provided with means for effectively defoaming bubbles generated in a circulating processing liquid and floating in a storage tank in a coating booth that collects surplus mist in spray coating using a processing liquid. .

In spray coating, there is a limit to the rate at which the paint sprayed from the spray gun is applied to the object to be coated to form a coating film, and generally 20% to 50% is scattered as surplus mist. . The scattered paint mist varies depending on various conditions such as a coating machine, an object to be coated, and a coating method. In any case, it is necessary to collect these scattered mists so that they are not discharged to the outside.

For this reason, a painting booth is used, and excess scattered paint mist is collected. Several methods are used to collect the paint mist, but most of them take the paint mist in the airflow using the treatment liquid, and collect and collect it in the treatment liquid using means such as aggregation or separation. A wet paint booth is used.
In the wet paint booth, a water tank is provided to circulate and supply the treatment liquid to the water flow film and shower formed to collect the paint mist, and the necessary treatment liquid is sent from there. Yes. Therefore, the treatment liquid that has collected the paint mist is returned to the water tank, where only the paint mist is removed and sent again to each part as a clean treatment liquid.

Since the paint mist taken in the processing liquid is contained in the processing liquid as a paint sludge, it is necessary to remove it effectively and to repeatedly use it as a circulating processing liquid. These methods differ depending on the paint used, and several methods are used.

Sludge taken in the circulating treatment liquid is dispersed as a fine paint sludge by detackifying treatment by adding chemicals, sucked together with the treatment liquid by means such as a pump, and the treatment liquid and sludge are separated by a device such as centrifugal separation However, there is a method for collecting only sludge. At this time, it is necessary to forcibly disperse the treatment liquid with an agitator or a mixing device in order to efficiently and averagely suck the suction with a pump or the like.

Also, in the process of circulating the treatment liquid, forming the water flow film or shower and returning it to the water tank again, it is inevitable that air bubbles will be involved by touching the air, and it will occur on the water surface when it returns to the water tank. become. Particularly in the case of water-based paints, bubbles are generated due to adhesiveness and surface tension, and these bubbles are difficult to disappear and are gradually accumulated in the water tank.

Further, a method of reducing the sludge separation and recovery by decomposing the paint sludge taken into the treatment liquid with microorganisms has been practically used. Since the treatment liquid in the painting booth (biobooth) by this method is alive, stirring is always performed for supplying oxygen, and the treatment liquid itself is blocked from foaming air as described above.

Such bubbling of the treatment liquid hinders the recovery process of the paint sludge and reduces workability. In addition, an adverse effect such as a problem that the processing liquid whose volume is increased by bubbles overflows from the wall surface of the water tank or is soiled by touching surrounding objects is also a burden on the operator. In addition, the basic function of sludge treatment like a biobooth is impaired.

In order to deal with such problems, many of the conventional measures have been to introduce an antifoaming agent to suppress foaming. However, the amount of water in the painting booth is large, a large amount of antifoaming agent must be used, and since the effect is reduced unless it is regularly replenished, the maintenance and costs associated with these are a heavy burden.

For this reason, a device known as a defoaming device having a mechanism of sucking floating bubbles, defoaming them by the action of centrifugal force, and then liquefying them back may be used. However, with this method, it is difficult to defoam the entire area of a large-area water tank, and an appropriate method has not been obtained.

On the other hand, as described above, in addition to a mechanical method and a chemical method such as an antifoaming agent as described above, there is a method using heat, particularly a cleaning device or a device with vibration and stirring. In some cases, a defoaming means by contact with the heating unit is used.

For example, in Japanese Patent Laid-Open No. 8-24510, in order to prevent bubbling from occurring when the effluent is distilled by a distiller and going to the condenser together with the foam, the vapor of the distiller is transferred to a multi-tube heat exchanger. A method is described in which bubbles are removed by evaporating water and solvent by feeding and heating with steam heat. In this way, there are techniques used in the environment in which the apparatus is installed, such as a technique of having a means for heating and extinguishing bubbles in a heating region that evaporates liquid at a high temperature.

The use of a heating element in a painting booth is concerned about the danger caused by heating of a volatile solvent-based paint, and has not been adopted so far. Moreover, it has not found a sufficient effect for defoaming a water tank having a wide water surface like the painting booth.
JP 2002-370087 A JP-A-6-114206 Japanese Patent Laid-Open No. 2003-10746 JP-A-8-24510

The purpose of the present invention is to obtain a painting booth that can effectively eliminate the foam generated on the surface of the water tank over a large amount of water and a large area, can reduce the burden on the maintenance of the worker without impairing the function of the painting booth. Specifically, it is to automatically eliminate the bubbles generated on the water surface of the painting booth and enhance the utilization effect of the circulating processing liquid.

In addition, it is a device capable of defoaming with simple operation without bothering the operator to maintain the suitability of the treatment liquid, such as defoaming work, and without daily cost by controlling defoaming as necessary The challenge is to be able to use the paint booth in an optimal condition at all times.

In the present invention, in the coating booth that sucks the sprayed paint mist and collects the paint mist collected by the processing liquid, the heating medium is arranged above the water surface of the water tank that stores the processing liquid to be circulated. .
The heating medium is configured by arranging heated pipes at appropriate intervals on the water surface at appropriate intervals and circulating a heating fluid inside, and arranging a heating medium whose surface has a temperature difference from the surroundings. Is. Moreover, the nozzle which blows a hot air as another heating medium is provided in the circumference | surroundings of a water tank, and a heat medium can be arrange | positioned by forming the hot air area which flows on the whole surface of a water surface.

Further, the heating medium is effectively set by controlling the temperature and time, and the operation is controlled in conjunction with the operation of the painting booth.
The heat medium placed on the water surface and heated on the surface can be moved, and a non-adhesive surface treatment process can be performed on the foam-contactable portion to obtain a more efficient coating booth.

In the operation of the coating booth, bubbles are generated by circulating the treatment liquid, and the bubbles flow into the stored water tank, gradually accumulate, overflow from the side wall surface of the water tank, and pollute the surroundings. Even if it does not overflow, paint sludge in the treatment liquid is scattered by some broken bubbles, and the unnecessary portions are fouled. According to the present invention, bubbles generated on the water surface are broken by contacting the surface of the bubbles with a heating medium such as a heating body or hot air, and generation of unnecessary bubbles can be prevented.

As for the heating medium, pipes with heating oil or steam inside are laid at appropriate intervals, and the hot surface ruptures the foam that comes in contact with it, drops into the water tank and is unnecessary. Generation of bubbles can be suppressed. The heating fluid has an advantage that the heating medium can be maintained safely at a required temperature by circulation and the control corresponding to the change of conditions depending on the properties of the treatment liquid and the paint used can be easily performed. Furthermore, the coating sludge that scatters due to the contact bubble breakage on the pipe can be maintained for a long period of time without being deposited and deposited by the non-adhesive surface treatment.

The water tank in the painting booth is widely opened because it periodically collects the paint sludge taken into the processing liquid, and there is a problem in terms of cost to lay the heating medium on the whole. When a means for blowing hot air toward the center from the surface is provided, it is possible to eliminate or prevent generation of bubbles on the entire surface. The hot air can be blown out at a time when the bubbles rise above a certain level, or in accordance with the operation of the painting booth, at a certain time interval, and can be operated at a minimum cost.

Furthermore, temperature adjustment of the heating pipe by blowing hot air as a heat medium or circulating a heated fluid can be easily performed by opening / closing control of valves, etc. It is easy to set and adopt the most efficient operation form. Other effects will be described together with the following embodiments.

FIG. 1 shows a schematic configuration diagram of a painting booth in the case of carrying out the present invention. A painting booth main body 1 is provided with a water tank 2 at the lower part, and sucks excess mist of paint sprayed on the upper part together with air. A mist processing chamber 3 for collecting and collecting the paint mist is provided. There are several paint mist treatment structures, but typically the paint mist is adsorbed when passing through the spray shower region D formed by sucking the treatment liquid W in the water tank with a pump and spraying it with a nozzle or the like. Then, it is dropped into the lower water tank together with the spray liquid.

In addition, there is a case where the treatment liquid near the water surface is sucked by the momentum of the air flow and the paint mist is collected in a water film or a spray region formed thereby. In such a case, the water level greatly affects the suction of the treatment liquid, and the generation of bubbles brings about a change in the water level, so it is necessary to reliably prevent it.

Further, a lot of means for collecting the paint mist that flows into the front plate 11 on the coating chamber A side as a water film C and collides with the treatment liquid W is incorporated. In any of the painting booths, a treatment liquid mainly composed of water is used, and a constant amount of liquid is always stored in the lower water tank 2. In the example shown in the figure, the taken paint mist is the rear opening 12. The structure is more recovered. Various techniques are used for the recovery means and apparatus, but are omitted here.

According to the example of FIG. 1 shown as an example, the coating booth structure is provided with a water flow plate 11 on which the processing liquid W flows down on the front surface of the coating chamber A, and with the air current in the rear processing chamber 3 at the lower end thereof. An opening 4 to the processing chamber 3 for collecting the sucked paint mist in contact with a spray shower or the like is formed. The treatment liquid W that has flowed down from the water flow plate 11 falls into the water tank 2 provided at the lower portion, which is a factor in the generation of bubbles. In the example shown in the figure, a lower water flow plate 13 is provided behind the opening 4 and a water flow is also formed on the floor surface 14.

On the other hand, the spray shower is configured to take in the paint mist that has been sprayed from the nozzle 5 and sucked by the exhaust fan 6 into the processing chamber 3. The treatment liquid W flowing to each of these parts gathers in the rear water tank 2 and is sent again by a pump through an appropriate filter or the like (not shown).
The treatment liquid W returning to the water tank 2 contains paint mist, and bubbles are generated due to factors such as entrainment of bubbles due to a collision and gradually increase on the water surface of the water tank, and the bubble surface rises.

In the example of FIG. 1, the pipe 9 disposed on the upper surface of the rear water tank 2 has a configuration in which the heating fluid fed from the heat source 10 circulates with a predetermined interval as shown in FIG. 2. As the circulating fluid, a fluid such as steam or oil is used. The flow rate can be adjusted by the control device 7, and a configuration in which the temperature, the circulation time, and the like are controlled according to the situation is provided.

Further, the bubbling of the treatment liquid W varies depending on the paint used and the agent such as the flocculant to be added, and the installation position of the pipe 9 is shown in FIG. 3 so that the distance from the foam surface or the water surface can be adjusted depending on the use situation. A movable means 8 as shown schematically is attached. For example, a configuration in which the pipe 9 is moved up and down using the rotation of a screw and connected to the control device 7 and the heat source 10 by a flexible tube is used.

In such an example, since the pipe 9 which is a heating body as a heating medium is directly defoamed by contact with the foam, the pipe 9 is easily contaminated by scattering of sludge in the liquid due to contact or foam breakage, and a means for preventing the dirt is required. It is done. Therefore, as a heating body having a surface with high thermal conductivity and low adhesion, for example, a metal pipe made of copper or the like coated with a fluorine-based resin is generally used.

As another example, as shown in FIG. 4, a hot-air pipe 15 is provided in the periphery of the water tank 2, and an injection nozzle 16 is provided at a required location of the hot-air pipe 15. The injection nozzle 16 is provided so that the above-mentioned several elements can be changed so that the hot air of high temperature can be distributed over the entire surface of the water, in addition to the position and the number of installations, the ejection amount, the ejection direction, etc. It is done.

These methods and means are selected from existing technologies and used. These combinations are diverse, and there are many choices and design factors depending on the width of the water surface and the state of the generated foam, but hot air is jetted downward from above the generated foam, and the hot air stream as the heating medium is blown to the water surface. The defoaming can be efficiently performed by spreading the whole area and bringing the fluidized heat source into direct contact with the foam.

Moreover, since the paint sludge contained at the time of the bubble breakage is scattered, these foams are positioned so that the bubble breakage is performed inside the wall of the aquarium and attached to the pipe 9. Even if it is a case, it is advisable to subject the surface to fluorine treatment so that it can be easily wiped off.

In the case of FIG. 4, the hot-air pipe 15 is provided along the inner edge in the longitudinal direction of the water tank 2, and the ejection nozzle 16 is inclined to the inside. Although it depends on the state of the blowout, if there is a range where the hot airflow can reach from the jetted area and there is a range where direct defoaming is not possible, it is only necessary to provide the jet nozzle 16 provided downward in the center. By selecting an arrangement according to the situation, defoaming can be efficiently performed.

Normally, the higher the temperature of the pipe as the heat medium or the heated air to be injected, the higher the effect.However, the lower the temperature, if the effect is obtained considering the economic efficiency and the increase in danger at high temperatures. As a result of confirmation, it was found that a sufficient effect was obtained at about 60 ° C.

Furthermore, in the example of FIG. 6, when a heated heat medium is installed on the water surface of the water tank, the heating element is composed of a tubular member in which the heating fluid circulates. The heat transfer body 18 may be formed by using only the pipe portion 19 and provided with a heat transfer body 18 formed of a metal having high heat conductivity. In this case, it is possible to arrange the heat transfer body in a well-balanced manner according to the foaming state in the water tank by moving the heat transfer body, and it is also possible to move it so as not to get in the way when performing maintenance in the water tank.

As described above, a region where a heat medium having a temperature higher than the surroundings exists is formed in the entire area where bubbles are generated in the water tank, and the region is desirably adjusted through the temperature management means and used for the paint or It is configured so that it can be changed by the treatment liquid in the painting booth. In an embodiment in which a heat source serving as a heat medium is circulated and used as a fluid, as a temporal control of circulation or ejection, a method of performing spraying and stopping by a manual valve to simply feed a preset heat source, and operation of a painting booth Use a method of jetting them together, or jetting them at appropriate intervals, and detecting the generation of bubbles on the water surface by means such as level detection, and jetting heated air according to the output signal. Can do.
Similarly, an efficient operation can be performed by grasping the state of generation of bubbles according to the conditions in coating and controlling the temperature or supply amount of the heat source that affects the defoaming effect.

It is schematic structure sectional drawing which looked at the painting booth of the present invention from the side. It is the layout of the heat medium which looked at the water tank part of the painting booth of FIG. 1 from upper direction. It is the figure seen from the side of FIG. 2, and is the schematic which showed the means to move a heating body up and down. It is a laying figure of the pipe for hot air provided with the nozzle which shows another practical example and uses a heating medium as hot air and sprays it on the water surface. It is the schematic which looked at FIG. 4 from the side. It is a schematic diagram at the time of making a heating body movable partially. It is the cross-sectional schematic which looked at FIG. 6 from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating booth body 2 Water tank 3 Processing chamber 4 Opening part 5 Nozzle 6 Exhaust fan 7 Control apparatus 8 Movable means 9 Pipe 10 Heat source 11 Front plate
12 Water tank opening 15 Pipe for hot air 16 Jet nozzle 18 Heat transfer body 19 Base tube part A Painting room B Foam C Water film D Spray shower area W Treatment liquid

Claims (2)

In a painting booth that sucks the sprayed paint mist and collects the paint mist collected by contact with the treatment liquid together with the treatment liquid, bubbles are placed above the surface of the water tank that stores the treatment liquid to be circulated and opens at the top. A non-adhesive surface-treated pipe is laid on the contactable part of the pipe, and a circulating treatment liquid characterized in that a means for circulating a heated fluid having a set temperature and circulation condition is connected to the pipe. Paint booth to use. The painting booth using the circulating processing liquid according to claim 1, wherein the heating fluid is adjusted in temperature and time, and the operation is controlled in conjunction with the operation of the painting chamber.

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