JP5546159B2 - Electrostatic powder coating booth - Google Patents

Description

  The present invention relates to a coating booth for electrostatic powder coating, and in particular, a coating booth for electrostatic powder coating that can efficiently adhere a powder coating sprayed to a workpiece from a coating gun to the workpiece. It is about.

  Electrostatic powder coating is a coating method in which a powder coating is sprayed onto an object to be coated with an electrostatic coating gun, and the powder coating is adhered to the object by static electricity.

  In this electrostatic powder coating, spraying of a powder coating material to an object to be coated is usually performed in a coating booth in order to prevent the powder coating material from scattering. The overspray powder that did not adhere to the object to be coated is collected and selected and reused.

  Electrostatic powder coating begins with road materials such as guardrails and fences, and is applied to household appliances such as refrigerators, microwave ovens, washing machines, and air conditioners. In recent years, wipers, oil filters, aluminum wheels, brakes are used. Many of them are used in car parts such as pads. In particular, electrostatic powder coating has been widely adopted for painting school chairs and desks from the viewpoint of environment and ecology.

  By the way, conventionally, the overspray powder is connected to a painting booth with a recovery duct, and the overspray powder is collected from the entire painting booth. Such a painting booth is also disclosed in Patent Document 1.

JP 2002-361121 A

  By the way, in general, when painting an object to be coated, the object to be coated is placed on a conveyor, and is painted in a painting booth via a pretreatment, water washing and draining drying furnace. In the painting booth, a suction duct connected to the dust collector is installed. In order to prevent the overspray powder from leaking outside the painting booth and to reuse the overspray powder, it is collected and returned to the paint tank again. ing.

  As described above, overspray powder can be reused for powder coating, but when the powder coating is sprayed onto the object to be coated from the coating gun, the powder paint that adheres to the object to be coated The greater the amount, that is, the higher the coating efficiency, the less overspray powder that does not adhere to the object to be coated, and the coating workability is improved.

  Therefore, in powder coating, it is important to increase the coating efficiency during the initial spraying.

  As a method for increasing the coating efficiency, there is conventionally known a method in which a reflecting plate formed by a flat plate is set up behind the object to be coated and the reflecting plate improves the adhesion of the object to the back surface. ing.

  However, since most of the overspray powder is rapidly pulled by the dust collector due to the suction force of the dust collector installed in the painting booth, the coating efficiency is hardly improved even if a reflector is installed in the rear. For this reason, in order to reduce the suction force of the dust collector and make it easier for the overspray powder to adhere to the object to be coated, for example, adjust the damper installed at the suction port of the dust collector in the closing direction, or use an inverter to The number of rotations of the dust collection motor may be reduced.

  However, if this is done, overspray powder leaks from the painting booth, resulting in a problem of deteriorating the environment around the painting booth. Also, in the production of one day, for example, if the dust collector's airflow is adjusted to the limit of airflow that does not cause powder leakage from the painting booth in the morning, and painting is performed, the factory can be used even if there is no powder leakage problem at the beginning. For example, scattering of overspray powder from the entrance / exit of the coating booth can be observed due to an increase in internal temperature (increase in ambient temperature) and an upward air flow due to increase in the temperature of the conveyor chain due to circulation in the baking furnace. In particular, when thick film coating is performed by preheating the object to be coated, the overspray powder tends to be rapidly scattered outside the coating booth due to the rising airflow due to temperature. Therefore, when the capacity of the dust collector in the painting booth is further improved and sucked, the powder paint discharged from the painting gun is rapidly sucked from the suction duct, so that the overspray powder is reattached to the object to be coated. Can't hope.

  Accordingly, an object of the present invention is to prevent the powder leakage from the painting booth and to easily re-attach the overspray powder to the object to be coated, thereby improving the coating efficiency at the time of spraying.

In order to solve the above-mentioned problem, the present invention has a coating booth having a double structure of a booth body provided with a suction duct connected to a dust collector and a powder coating convection chamber surrounding an object to be coated. A paint gun is installed in the paint convection chamber, the powder paint is sprayed onto the object to be coated in the powder paint convection chamber, and the powder paint convection chamber is maintained at a positive pressure state by spraying the powder paint from the electrostatic paint gun. The powder paint is filled in the convection chamber and attached to the object to be coated, and the overspray powder leaking from the powder convection chamber is sucked from the booth body and supplied to the dust collector. is there.

  The object to be coated passes through the booth body and the powder coating convection chamber by the conveyor, and the powder coating is sprayed while passing through the powder coating convection chamber.

  The electrostatic coating gun protrudes from the wall surface of the powder coating convection chamber and seals the space between the wall surface of the powder coating convection chamber and the gun coating tip of the electrostatic coating gun. Overspray powder can be prevented from leaking from the gap between the paint convection chamber and the wall surface.

  In addition, if an electrostatic coating gun is installed so that the panel on the wall of the powder coating convection chamber and the gun tip of the electrostatic coating gun are flat, the flow of overspray powder in the powder coating convection chamber will depend on the gun tip. Since it is not obstructed, the overspray powder easily circulates in the powder coating convection chamber, and the opportunity for the overspray powder to adhere to the object to be coated increases. Moreover, if the panel of the wall surface of the powder coating convection chamber in which the electrostatic coating gun is installed is flat, cleaning can be easily performed.

  It is desirable to install a plurality of electrostatic coating guns at positions facing the powder coating convection chamber in order to increase the chance of overspray powder adhering to the object to be coated.

  In order to adjust the flow of overspray powder in the powder coating convection chamber, it is desirable to install sleeves extending toward the entrance / exit of the booth body at the entrance / exit of the object to be coated in the powder coating convection chamber.

  Furthermore, by providing sleeves at the entrance and exit of the powder coating convection chamber so that the length can be adjusted toward the entrance and exit of the booth body, the flow of the overspray powder in the powder coating convection chamber can be adjusted, thereby More overspray powder can be adhered to the coated object.

  Also, in order to adjust the flow of overspray powder in the powder coating convection chamber and prevent powder leakage from the entrance / exit of the booth body, go to the entrance / exit of the coated object in the booth body and to the entrance / exit of the powder coating convection chamber. It is preferable to install a sleeve extending in the direction of the booth and to adjust the length of the sleeve at the entrance / exit of the booth body toward the entrance / exit of the powder coating convection chamber.

  Furthermore, in order to improve the circulation of the powder paint filling the powder paint convection chamber in the powder paint convection chamber and increase the chance of the powder paint adhering to the object to be coated, the air ejection device is changed to powder paint. Can be installed in the convection chamber.

  The bottom of the powder coating convection chamber has an opening that allows the overspray powder to flow out, and the size of the opening below is adjusted to adjust the flow of the overspray powder in the powder coating convection chamber. It is desirable to install an adjusting plate.

  A recovered powder tank for storing overspray powder can be installed below the opening at the bottom of the powder coating convection chamber.

  Then, an electrostatic coating gun that blows the overspray powder collected in the collected powder tank into the powder coating convection chamber is installed in the collected powder tank installed on the bottom of the powder coating convection chamber. The coating efficiency of the powder coating can be improved.

  By providing the powder paint convection chamber so as to be movable with respect to the booth body, the color change work can be efficiently performed by replacing and cleaning the powder paint convection chamber.

  In order to adjust the flow of overspray powder in the powder coating convection chamber and to minimize powder leakage from the booth body, the position of the suction duct on the booth body is changed along the conveying direction of the workpiece. It is desirable to install it as possible.

  In the present invention, as described above, the powder paint convection chamber surrounding the object to be coated is installed in the booth body, and the powder paint is sprayed on the object to be coated in the powder paint convection chamber. The powder coating material is filled in the powder coating convection chamber without being rapidly sucked from the suction duct of the booth body, and the object to be coated and the powder coating are in sufficient contact within the powder coating convection chamber.

  Therefore, most of the sprayed powder coating adheres to the object to be coated in the powder coating convection chamber, improving the coating efficiency of the powder coating and reducing the amount of overspray powder leaking from the powder coating convection chamber. Therefore, the overspray powder leaking from the powder coating convection chamber can be reliably sucked from the suction duct of the booth body, and powder leakage from the booth body can be prevented.

1 is a schematic transverse plan view showing a first embodiment of a coating booth for electrostatic powder coating according to the present invention. It is a schematic longitudinal cross-sectional front view of embodiment of FIG. It is the schematic side view which notched the booth main body of embodiment of FIG. It is a schematic longitudinal cross-sectional front view which shows the modification of embodiment of FIG. It is a schematic longitudinal front view which shows the modification of the powder coating material convection chamber of embodiment of FIG. It is a schematic longitudinal cross-sectional front view which shows the attachment modified example of the electrostatic coating gun to the powder coating material convection chamber of embodiment of FIG. It is a general | schematic cross-sectional top view which shows 2nd Embodiment of the coating booth of electrostatic powder coating based on this invention. It is a schematic longitudinal front view of the embodiment of FIG. It is the schematic side view which notched the booth main body of embodiment of FIG. It is a schematic cross-sectional top view which shows the example of installation of the powder coating material convection chamber of embodiment of FIG. It is a general | schematic cross-sectional top view which shows 3rd Embodiment of the coating booth of electrostatic powder coating based on this invention. It is a schematic longitudinal cross-sectional front view of embodiment of FIG. It is a schematic longitudinal cross-sectional front view which shows the modification of the coating material tank installed in the lower part of the powder coating material convection chamber of embodiment of FIG.

  A first embodiment of a painting booth according to the present invention will be described.

  The painting booth according to the first embodiment is used for painting crescent-shaped agricultural equipment parts, for example, and as shown in FIGS. 1 to 3, a booth body 1 having a suction duct 2 connected to a dust collector 3 and , A double structure with the powder coating convection chamber 4 surrounding the article A to be coated.

  The powder coating convection chamber 4 is installed so as to surround the four directions of the object A to be coated. However, the booth body 1 and the powder coating convection chamber 4 have entrances 5 and 6 through which the object A passes. The object to be coated A passes through the booth main body 1 and the powder coating convection chamber 4 by the transfer conveyor 7, and is powdered by the electrostatic coating gun 8 while passing through the powder coating convection chamber 4. Paint B is sprayed.

  On the opposite side walls of the powder coating convection chamber 4, electrostatic coating guns 8 are installed so that two guns face each other. In this embodiment, a frictional charging gun with a number of branch nozzles 27 is employed. The electrostatic coating gun 8 may be a corona charging gun, and the application method to the powder coating B is not particularly limited.

  The gun tip of the electrostatic coating gun 8 is fixed to the wall surface of the powder coating convection chamber 4 and the gap between the gun tip and the wall surface is sealed. The opposing electrostatic coating guns 8 are arranged so that their spray patterns collide with each other.

  A slit-shaped opening 9 is provided in the lower bottom surface of the powder coating convection chamber 4. An adjustment plate 10 for adjusting the width of the slit-shaped opening 9 is installed on the wall surface of the opening 9 so as to be movable up and down.

  The powder coating convection chamber 4 is movably installed in the booth main body 1 by a column 24 with wheels 23, but may be supported by being suspended from the booth main body 1.

  Sleeves 11 extending toward the entrance / exit 5 of the booth body 1 are installed at the entrance / exit 6 of the object A to be coated in the powder coating convection chamber 4. The sleeve 11 is composed of inner and outer double cylindrical members, and leaks out of the powder coating convection chamber 4 by adjusting the distance between the booth body 1 and the entrance 5 by expanding and contracting the inner and outer double cylindrical members. The flow and amount of overspray powder can be adjusted.

  The article A to be coated is suspended on a conveyor 7 installed above the booth main body 1 and drawn from the booth main body 1 into the powder coating convection chamber 4. B is sprayed, and thereafter, it is pulled out from the booth body 1 through the entrance 6 of the powder coating convection chamber 4 and the entrance 5 of the booth body 1.

  When the workpiece A is drawn into the powder coating convection chamber 4, the branch nozzle 27 of the electrostatic coating gun 8 installed at the opposite position of the side wall of the powder coating convection chamber 4 moves toward the coating A. Powder coating B is sprayed and coating is started.

  The powder coating B discharged from the electrostatic coating gun 8 adheres to the object A in the powder coating convection chamber 4. Then, the powder coating B is first violently collided by the electrostatic coating gun 8 installed at the opposite position, and the direction of the powder coating B becomes scrambled by the momentum, and again the object A to be coated is applied. Adhere toward. The powder coating B that has not adhered again collides with the wall surface of the powder coating convection chamber 4, changes its direction, and tends to adhere toward the object A to be coated.

  In this embodiment, the panel constituting the wall surface of the powder coating convection chamber 4 uses a polypropylene insulating resin. The material of the panel may be other resins such as vinyl chloride and polycarbonate. Moreover, a metal panel may be sufficient.

  Although no suction device is installed in the powder coating convection chamber 4, the powder coating convection chamber 4 is in a positive pressure state due to the discharge of the powder coating B from the electrostatic coating gun 8. Part of the overspray powder leaks from the entrance / exit 6 of the convection chamber 4 to the booth body 1 and is sucked into the suction duct 2 of the booth body 1.

  Thus, the overspray powder collides with the inner surface of the wall surface of the powder coating convection chamber 4 and rebounds, and re-adhesion is repeated on the object A to be coated. Thus, the powder coating material A discharged from the electrostatic coating gun 8 adheres to the object A to be coated with high coating efficiency. Since the powder paint convection chamber 4 is in a positive pressure state, the overspray powder finally leaks into the booth body 1.

  Since the booth body 1 is forcibly sucked (exhausted) by the suction duct 2 connected to the dust collector 3 and the booth body 1 has a negative pressure, the overspray powder leaking from the powder coating convection chamber 4 is It is sucked into the suction duct 2 of the booth body 1 and collected by the dust collector 3.

  Next, in the embodiment of FIGS. 1 to 3, each corner portion of the inner surface of the powder coating convection chamber 4 has an acute angle or 90 °, but it collides with the wall surface of the overspray powder in the powder coating convection chamber. In order to increase the number of times, as shown in FIG. 4, the corner portion 12 is made a curve (R) type so that the discharged powder paint B can easily circulate in the powder paint convection chamber 4. Good.

  Furthermore, in order to increase the number of collision rotations of the overspray powder in the powder coating convection chamber 4 and increase the chance of the overspray powder adhering to the object A, as shown in FIG. The air jet device 13 may be installed in the powder coating convection chamber 4.

  In the embodiment of FIGS. 1 to 3, the gun tip nozzle of the electrostatic coating gun 8 is installed so as to protrude into the powder coating convection chamber 4, but as shown in FIG. If the panel 14 is installed so that the wall surface of the electrostatic coating gun 8 and the tip of the electrostatic coating gun 8 are flat, the flow of the overspray powder in the powder coating convection chamber 4 is not blocked by the tip of the gun. Becomes easier to circulate in the powder coating convection chamber 4, and the chance of the overspray powder adhering to the object A to be coated increases. In addition, by flattening the inner surface of the powder coating convection chamber 4 by the panel 14, the wall surface of the powder coating convection chamber 4 can be easily cleaned.

  By adjusting the gap between the sleeve 11 of the entrance / exit 6 of the powder coating convection chamber 4 and the entrance 5 of the booth main body 1, the outside air from the entrance 5 of the booth main body 1 and the powder leakage speed from the powder coating convection chamber 4 are reduced. Can be adjusted. In this embodiment, as shown in FIG. 3, the length of the sleeve 11 made of an inner and outer cylindrical member provided at the entrance / exit 11 of the powder coating convection chamber 4 can be adjusted. Moreover, as shown in FIG.1 and FIG.3, you may make it adjust the sleeve 15 of the entrance / exit 5 of the booth main body 1. FIG. The reason for this adjustment is that the flow direction of the overspray powder in the powder coating convection chamber 4 is adjusted depending on the shape of the article to be coated A when importance is attached to the front and rear of the traveling direction of the conveyor 7. Thus, the front and back surfaces of the article A can be improved. For example, most of the flow of the overspray powder in the powder coating convection chamber 4 may flow in the traveling direction of the article A to be coated, or on the contrary, it may flow much in the inlet direction of the article A to be coated. It becomes possible. In this embodiment, the sleeve 11 is formed so that the overspray powder flows from the center of the electrostatic coating gun 8, that is, from the center portion of the powder coating convection chamber 4 to both the inlet / outlet 6 of the powder coating convection chamber 4. Is adjusted. Moreover, in this embodiment, the electrostatic coating gun 8 eliminates the powder leakage from the gap by inserting the powder paint convection chamber 4 from the panel, thereby eliminating the gap between the gun tip and the overspray powder. Use efficiency is improved.

  Next, a second embodiment will be described with reference to FIGS. In this embodiment, similarly to the first embodiment, a powder coating convection chamber 4 surrounding the article to be coated A is installed in the booth body 1. Portions common to the first embodiment are denoted by common reference numerals and description thereof is omitted.

  The bottom surface of the powder coating convection chamber 4 is inclined toward the center, and is closed by installing a recovered powder tank 16 below the bottom.

  On the side surface of the booth main body 1, a total of four corona guns as electrostatic coating guns 8 are installed on one side in opposing positions by a reciprocator 17 installed outside the booth main body 1. In this second embodiment, the electrostatic coating gun 8 is installed at the opposing position, but it may be installed only on one side for painting.

  The coating material is supplied to the electrostatic coating gun 8 by an injector 28 from a collected powder tank 16 installed at the lower part of the powder coating convection chamber 4. The recovered powder tank 16 is replenished with a new powder paint by an injector 25 from a paint box 18 installed outside the booth body 1.

  Coating is performed in the powder coating convection chamber 4 in the same manner as in the first embodiment, and the overspray powder adheres to the object to be coated again while rotating in the powder coating convection chamber 4.

Using the coating booth of the second embodiment, a coating experiment was performed under the following coating conditions. Further, as a comparative example, the powder coating convection chamber 4 was not installed in the booth main body 1, and a coating experiment was performed only with the booth main body 1 under the same coating conditions.
(Painting conditions)
・ Conveyor speed: 1.0m / min
・ Hanger pitch: 400mm
・ Discharge amount: 60 g / min × 4 gun = 240 g / min (discharge amount per hour: 14,400 g)
(When powder coating convection chamber 4 is used)
・ Recovered powder in tank for 1 hour: 4,740 g
・ Overspray powder for 1 hour dust collector: 2,160g
・ Adhesion amount: 50 g / hanger ・ Coating efficiency: 50 × 1000 ÷ 400 ÷ 240 × 100 (%) = 52 (%)
・ Use when powder paint collected only in powder paint convection chamber 4 is reused without powder paint leaking into booth body 1 using powder paint convection chamber 4 dedicated to 5 colors When the efficiency (%) is calculated, (14,400-2,160) ÷ 14,400 × 100 (%) = 85 (%).
(When painting with booth body 1 only without using powder coating convection chamber 4)
・ Overspray powder to dust collector for 1 hour: 8,100g
・ Adhesion amount: 42 g / hanger ・ Coating efficiency: 42 × 1000 ÷ 400 ÷ 240 × 100 (%) = 43.7 (%)

  As a result of the above experiment, when the powder coating convection chamber 4 was installed in the booth main body 1 for coating, the coating efficiency was 52%. On the other hand, when the painting is performed only by the booth body 1 without installing the powder coating convection chamber 4, the coating efficiency is 43.7%, which is a big difference from the case where the powder coating convection chamber 4 is installed. It was seen. In this embodiment, an illumination component is used as the object A to be coated. However, it is better that the powder coating convection chamber 4 is installed in the recess (shadow). Further, in this experiment, about 70% of the overspray powder moves to the entrance / exit 6 on the traveling direction side of the article A to be coated, at the entrances 6, 5 of the booth body 1 and the powder coating convection chamber 4. Sleeves 11 and 15 were adjusted. In this case, not only adjustment of the powder coating convection chamber 4 and the sleeves 11 and 15 of the booth body 1, but also the flow of the overspray powder by changing the position of the suction duct 2 to the dust collector 3 as shown in FIG. It was also possible to adjust easily.

  In this embodiment, among the four suction ducts 2, the suction duct 2 at the forefront in the traveling direction is opened, and the other three suction ducts 2 are closed by the dampers 19 to change the suction position. However, the suction port of the suction duct 2 may be adjusted by sliding. Finally, a part of the overspray powder leaks from the entrance / exit 6 of the powder coating convection chamber 4 and is forcedly exhausted from the suction duct 2 of the booth body 1 to the dust collector 3. However, most of the overspray powder that has adhered to the object A after being repainted many times falls naturally into the recovered powder tank 16 installed at the bottom of the lower part in the powder coating convection chamber 4. This overspray powder is immediately mixed with new powder, applied again by the electrostatic coating gun 8, and discharged toward the object A to be coated. For this reason, the powder coating material B exhausted to the booth body 1 was 15% of the total discharge amount. When this object A is painted only in the booth body 1 and an equivalent coverage is obtained, an extra 20% is required for the discharge amount. The reason is that in the powder coating convection chamber 4, This is because the overspray powder hits the wall surface of the powder coating convection chamber 4 and repeats the re-adhesion over and over, resulting in increased coverage and adhesion efficiency. Therefore, the amount of recovered powder is reduced when the powder coating convection chamber 4 is installed. Generally, the recovered powder has a different paint particle size distribution than the new powder. For this reason, compared with the method performed only by the conventional booth main body 1, the new recovered powder becomes rich in the new powder, and the amount of discharge is small, so that proper coating is possible.

  By the way, in the case of electrostatic powder coating, there is a merit of reusing the recovered powder, but if the previous powder paint color remains, the color changes as it is in the coating film. In other words, it becomes a mottled pattern. Cleaning in the painting booth can be visually confirmed and removed by air blow or dusting, but for example, it is practically difficult to clean the paint adhering to the inside of the duct from the painting booth and the dust collector. That is, a duct or dust collector dedicated to each color is required.

  As described above, in the painting booth according to the present invention, there is little overspray powder leaking from the entrance / exit 6 of the powder paint convection chamber 4, and most of the collected powder is collected on the bottom bottom of the powder paint convection chamber 4. Return to flour tank 16. For this reason, even if only the overspray powder leaked from the powder coating convection chamber 4 is used exclusively for recovery, the reuse rate is not greatly reduced.

  In the embodiment of FIG. 10, five powder coating convection chambers 4 are installed on one booth body 1 according to the coating color, and the five powder coating convection chambers 4 are respectively provided on the floor surface. When the color is changed, the powder paint convection chamber 4 is drawn out of the booth main body 1 by the moving stand 20 and the next paint color is changed. The powder paint convection chamber 4 can be replaced.

  If the powder coating convection chamber 4 is dedicated to each color as in the example of FIG. 10, the cleaning of the powder coating convection chamber 4 is simply performed before the movement when changing colors. Further, since the coating booth of this embodiment has a small amount of the powder coating B leaking from the powder coating convection chamber 4, even if the powder coating B sucked from the booth main body 1 is discarded, the recovery efficiency is much higher. Has no effect. Therefore, at the time of color change, cleaning of the booth main body 1, the suction duct 2 and the dust collector 3 can be omitted and color change can be performed. In this way, by changing the powder coating convection chamber 4 to be actually applied to a dedicated color, the color can be easily changed in a short time.

  Moreover, the powder coating convection chamber 4 may be cleaned to change the color. Since the powder coating convection chamber 4 is smaller than the booth main body 1, it can be visually confirmed during cleaning, and thus cleaning is easy.

  Next, a third embodiment will be described. In the third embodiment, the steel furniture component is the article to be painted A.

  The settings of the powder coating convection chamber 4 and the electrostatic coating gun 8 are the same as in the second embodiment, but as shown in FIG. 11, one electrostatic coating gun 8 is additionally installed on the bottom surface. . In other words, painting is performed with a total of 5 guns. The electrostatic coating gun 8 installed on the wall surface of the powder coating convection chamber 4 is directly transported by the injector 25 from the coating box 18 installed outside the booth body 1 to perform coating. The electrostatic coating gun 8 from the bottom surface is directly sucked by the injector 21 from the collected powder tank 16 installed at the lower portion to perform coating. This lower electrostatic coating gun 8 has no powder coating hose. An injector 21 is installed directly in the collected powder tank 16, and the collected powder is supplied from the injector 21 to the electrostatic coating gun 8 and discharged. In the third embodiment, the recovered powder alone is insufficient for the paint. In that case, although not shown, new powder is replenished and supplied from the paint box 18 by leveler control of the collected powder in the collected powder tank 16. Further, as shown in FIG. 13, a fiber drum made of commercially available paper may be used as the recovered powder tank 16. The recovered powder tank 16 made of a fiber drum is installed on a vibration table 28 having a vibrator 26 at the lower portion, and has a structure in which the powder coating material of the injector 21 cannot be dented due to the vibration. In this embodiment, since the number of colors is large, the powder coating convection chamber 4 is cleaned to change colors. A system that can reuse most of the recovered powder is adopted. Therefore, the booth main body 1, the suction duct 2, and the dust collector 3 are not cleaned as in the second embodiment. However, in order to eliminate contamination, it is preferable to clean only the booth main body 1 after daily production by daily inspection and cleaning.

  As can be seen from the contents of the above three embodiments, during coating, the inside of the powder coating convection chamber 4 surrounding the object to be coated becomes a positive pressure, and the overspray powder repeatedly adheres again and again. By flowing toward the doorway 6 of A, only a part of the overspray powder leaks into the booth body 1 while increasing the adhesion efficiency. And since the overspray powder leaked from the powder coating convection chamber 4 has a negative pressure in the booth body 1, the overspray powder is reliably collected in the suction duct 2, so that the powder leaks from the booth body 1. It is possible to prevent contamination from the surrounding environment.

DESCRIPTION OF SYMBOLS 1 Booth main body 2 Suction duct 3 Dust collector 4 Powder coating convection chamber 5 Entrance / exit 6 Entrance / exit 7 Transfer conveyor 8 Electrostatic coating gun 9 Opening part 10 Adjustment plate 11 Sleeve 12 Corner part 13 Air ejection apparatus 14 Panel 15 Sleeve 16 Collected powder tank 17 Reciprocator 18 Paint box 19 Damper 20 Moving base 21 Injector 22 Paint box 23 Wheel 24 Strut 25 Injector 26 Vibrator 27 Branch nozzle 28 Injector A Object to be coated B Powder paint

Claims (14)

It consists of a double structure consisting of a booth body equipped with a suction duct connected to a dust collector and a powder paint convection chamber surrounding the object to be coated. An electrostatic coating gun is installed in the powder paint convection chamber, and the powder paint convection The powder coating is sprayed onto the object to be coated in the room, and the powder coating convection chamber is kept at a positive pressure by spraying the powder coating from the electrostatic coating gun, and the powder coating is filled into the powder coating convection chamber. This is an electrostatic powder coating booth in which the overspray powder leaked from the convection chamber is sucked from the booth body and supplied to the dust collector.   2. An electrostatic apparatus according to claim 1, further comprising a conveyor for conveying an object to be passed through the booth body and the powder coating convection chamber, wherein the powder coating is sprayed on the object to be coated while passing through the powder coating convection chamber. Powder coating booth. The electrostatic coating gun according to claim 1 or 2, wherein a gun tip of the electrostatic coating gun protrudes from a wall surface of the powder coating convection chamber, and the wall surface of the powder coating convection chamber and the gun tip of the electrostatic coating gun are sealed. Powder coating booth.   The coating booth for electrostatic powder coating according to any one of claims 1 to 3, wherein the wall surface of the powder coating convection chamber and the gun tip of the electrostatic coating gun are installed flat. The electrostatic powder coating painting booth according to any one of claims 1 to 4 , wherein a plurality of electrostatic coating guns are installed at positions opposed to the powder coating convection chamber. The electrostatic powder coating painting booth according to any one of claims 1 to 5 , wherein a sleeve extending toward the entrance / exit of the booth body is installed at the entrance / exit of the object to be coated in the powder coating convection chamber. The coating booth for electrostatic powder coating according to claim 6 , wherein sleeves at the entrance and exit of the powder coating convection chamber are provided so that the length can be adjusted toward the entrance and exit of the booth body. A sleeve extending toward the entrance and exit of the powder coating convection chamber is installed at the entrance and exit of the booth body, and the length of the sleeve at the entrance and exit of the booth body is adjustable toward the entrance and exit of the powder coating convection chamber. The coating booth for electrostatic powder coating according to any one of claims 1 to 7 . The coating booth for electrostatic powder coating according to any one of claims 1 to 8 , further comprising an air ejection device that circulates the powder paint filling the powder paint convection chamber in the powder paint convection chamber. The bottom surface of the powder coating convection chamber, an opening is provided for discharging the overspray powder to the opening, according to any of claims 1-9 which is a regulating plate for regulating the size of the opening The electrostatic powder coating booth. The coating booth for electrostatic powder coating according to any one of claims 1 to 10 , wherein a collection powder tank for storing overspray powder is installed below an opening at the bottom of the powder coating convection chamber. The recovery powder tank installed at the bottom surface of the powder coating convection chamber, any term in the recovery powder according to claim 1 to 11 in which the reservoir powder coating in the tank was installed electrostatic spray gun to blow the indoor powder coating convection The electrostatic powder coating painting booth described in 1. The coating booth for electrostatic powder coating according to any one of claims 1 to 12 , wherein the powder coating convection chamber is provided so as to be movable with respect to the booth body. The electrostatic powder coating coating booth according to any one of claims 1 to 13 , wherein the position of the suction duct of the booth main body is changeable along the conveying direction of the object to be coated.

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