JPS6218221B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder filtration device, particularly a powder coating booth having a powder filtration device for recovering powder paint in an electrostatic powder coating device.

Generally, there are several methods and devices for applying powder coatings to objects to be coated, and the currently widely used method is to use a coating machine to spray powder coatings onto objects to be coated. In particular, the most common method is to use an electrostatic powder coating machine to charge a powder coating and spray it onto the object to be coated using the electrostatic attraction force. In this case, the coating rate of the powder coating sprayed from the electrostatic powder coating machine varies depending on the shape of the object to be coated, the shape and type of particles of the powder coating, and other conditions, but it is approximately 80 - 30%, and approximately 20-70% of the sprayed powder paint is not coated on the object to be coated. Therefore, it is important to recover this unpainted powder coating.

In this type of electrostatic powder coating, the object to be coated is supported by a conveyor and transported into a coating room, that is, a coating booth, and is powder-coated by an electrostatic powder coating machine while passing through the coating booth. be done. In order to collect unpainted powder paint in such a painting booth, a centrifugal powder collection machine or a bag-type collection machine is connected to the outside of the painting booth, but these collection machines have different types. When performing ivy-colored powder coating, it is extremely difficult to clean the interior of the collecting machine and auxiliary equipment, color mixing occurs, and the collected powder coating cannot be reused.

In addition to this collection method, another collection method has been developed in which a paint booth is equipped with a contact type electric field curtain facing an electrostatic powder coater to collect unpainted paint inside the paint booth. This contact type electric field curtain is installed on the entire wall surface of the painting booth on the side facing the paint machine. In other words, the electric field curtain is composed of a filter consisting of a large number of electrode rows arranged at intervals in a plane, an overlayer provided immediately behind these electrode rows, and a wire mesh that reinforces and holds the overlayer. The uncoated paint flows towards the electrode rows of the electric field curtain filter in the airflow of suction air acting on the electric field curtain filter, where it is unified by the electric field curtain generated by the electricity applied to the electrode rows. The remaining uncoated paint is brushed off and collected in a suitable powder paint collection machine. The remaining unapplied paint is deposited on the overfill of the filter. The deposited paint is brushed off by applying a back pressure to the filter at a certain time to bring the excess material closer to the electrode array, and the deposited paint is brushed off by the action of the electric field. This kind of operation is repeated at regular intervals using a timer to brush off unapplied paint from the booth floor and collect it with a collection machine, but with powder paints where the powder particles are extremely small, it is completely removed. It is difficult to Since one entire wall of the painting booth constitutes an electric field curtain filter, a large number of electrodes are used, and the internal wiring of the terminal box connected and branched from the power supply becomes complicated.
In addition, since a high voltage is applied, a large amount of insulating material is used, making it expensive, making it difficult to clean the large number of electrodes, and repairing the electrodes is not easy.

Therefore, an object of the present invention is to eliminate such drawbacks by providing a driving type for the overfill material in a cylindrical or wide loop shape, and for forming an electric field curtain in a part of the overfill material in this driving type. The electrode is installed close to the overfill material, and the unpainted paint adhering to the moving overfill material is brushed off and collected by an electric field curtain, making it easy to clean, without color mixing, and with a high recovery rate. An object of the present invention is to provide a powder coating booth having a powder filtration device that enables the reuse of recovered paint.

Other objects, features and advantages of the invention will become apparent from the following detailed description of several embodiments of the powder coating booth of the invention, taken in conjunction with the accompanying drawings.

An embodiment of the powder coating booth of the present invention is shown in FIGS. 1 to 3, and the powder coating booth 1 is a coating booth main body where coating is performed when objects to be coated supported by a transfer conveyor 2 pass. 3, and an electrostatic powder coating machine 4 installed on one side of the painting booth body 3.
and a powder passing device 5 provided on the other side facing the electrostatic powder coating machine 4. The floor surface of the painting booth main body 3 consists of an electric field curtain panel 6 tilted toward the center, and a powder collecting machine 7 is provided at one end of the central recess, and the collected powder paint can be supplied to the electrostatic coating machine 4. Yo hose 8
is connected. The sprayer 4 is also connected to a high-voltage power source 9 to charge the powder coating to be sprayed.

The powder filtration device 5 has two upright rotatable tubes 11, and the insides of these rotatable tubes 11 are connected to an exhaust duct 12. Each over-tube 11 has a bag-like over-material 14 on the outside of the cylindrical wire mesh 15.
A tightening material 1 is attached to the shoulder of a steel plate cylindrical portion 16 fixed to the upper end of the cylindrical wire mesh 15.
7 so that the overfill material 14 is firmly held. Further, the steel plate cylindrical portion 16 has a bearing 19 mounted on a fixed short cylindrical member 18 fixed to the ceiling 10 of the booth main body 3.
It is rotatably supported by and rotated via a drive chain 22 by a suitable drive 21, such as an electric motor, mounted on the exhaust duct 12.

The electric field curtain electrode 25 is connected to the overcoat 1 of the overtube 11.
4, it is removably fixed and supported by upper and lower fixing members 26, and, for example, a single-phase or multi-phase AC voltage is applied from a power source 28 via an electric wire 27, and an electric field curtain is formed by the electrodes 25. ing.

A suitable blower (not shown) is connected to the exhaust duct 12 and sucks the air inside the coating booth 3 in the direction of the arrow through the overfill 14 to form an air flow inside the coating booth 3.

In such a powder passing device 5, the cylindrical metal 15 and the passing member 14 constituting the passing cylinder 11 are rotated, for example, in the direction of the arrow (FIG. 3). For example, an electric field curtain electrode 2 with a diameter of about 5 mm is provided on the outside of the overlayer 14.
5 are attached at intervals of about 10 mm, 2 to 4 mm apart from the overlay material 14, and form an electric field curtain. The powder coating material 30 adhering to the overfill material 14 is brushed off from the overfill material 14 by the electric field curtain action when the overfill tube 11 rotates and approaches the electrode 25.

To assist in enhancing the effect of brushing off the powder coating material 30, a fixed fan-shaped buffle 32 is provided within the cylindrical metal 15 of the overtube 11, as shown in FIG. This fan-shaped buttful 32 is a sealed box, and a large number of small holes 33 are provided on the surface facing the electric field curtain electrode 25, and a compressed air pipe 34 is provided.
For example, when a large number of fine powder particles adhere to the area around the electric field curtain electrode 25, the solenoid valve 35 is opened, compressed air is supplied, and the compressed air is blown out from the small hole 33 of the fan-shaped buttful 32. to clean the electric field curtain electrode 25.

FIG. 4 is an explanatory diagram of the principle of electric field curtain, in which charged particles 37 are connected to electrodes 2 connected to three-phase alternating current u, v, w.
When it enters the field 38 of the electric field curtain generated during 5, it vibrates and floats due to the effect of the electric field curtain, and is moved to the right or left by the current change of the three-phase AC power supply 28.

According to the powder coating booth of the present invention configured in this manner, the objects to be coated supported by the transfer conveyor 2 are kept stationary in the coating booth 3 while entering the coating booth 3 through the entrance and leaving through the exit. Powder paint is applied by an electric powder coating machine 4. During powder coating in the coating booth 3, unapplied paint is directed toward the overtube 11 by the airflow inside the coating booth 3, which is generated by suction through the exhaust duct 12 and the overtube 11. The uncoated powder paint is carried and adhered to the surface of the overfill material 14, and the exhaust gas separated from the powder paint is discharged through the exhaust duct 12. The powder coating attached to the surface of the overmaterial 14 is
When it approaches the electric field curtain electrode 25, it is brushed off from the surface of the overfill material 14 by the electric field curtain action. The powder paint that has been brushed off is carried on the electric field curtain panel 6 on the floor,
It is collected and recovered by a recovery machine 7. When powder paint adheres to the electric field curtain electrode 25 and it becomes necessary to clean it, the electromagnetic valve 35 is opened and compressed air is supplied to the fan-shaped baffle 32 and blown out from the small hole 33. Electric field curtain electrode 2
It is possible to remove the powder paint adhering to 5. The uncoated powder paint collected by the collection machine 7 can be reused, and can be supplied to the coating machine 7 through the hose 8 and used again for electrostatic powder coating. In addition, since the number of electric field curtain electrodes 25 used is small, cleaning becomes easy, and since the overtube 11 and overfill material 14 can be easily replaced, there is no problem in changing the color of the paint, and color mixing is possible. Advantages such as the ability to effectively collect and reuse uncoated powder coating without any waste are achieved.

FIG. 5 shows another embodiment of the coating booth of the present invention, and this coating booth 1' uses a wide loop-shaped electrostatic powder filtration device 50. In this embodiment, a coating booth main body 3, an electrostatic powder coating machine 4, an electric field curtain panel 6 on the booth floor,
The powder paint recovery machine 7 and the like are the same as those in the previous embodiment. The filter material 51 of the electrostatic powder filtering device 50 is provided on one side of the coating booth 3, that is, the side corresponding to the coating machine 4, and is formed in the shape of at least one wide loop, for example, an endless belt, It is driven in the direction of the arrow by a drive shaft 52 driven by a suitable drive device 54 such as an electric motor.
The loop-shaped hollow portion of the filter material 51 is connected to an exhaust duct 55, and is suctioned and exhausted through the exhaust duct 55 by an appropriate blower (not shown). Further, an electric field curtain electrode 57 is provided at the lower part of the overlayer 51, and a voltage is applied from the power source 28 to form an electric field curtain.

In such a coating booth, the object to be coated supported by the transfer conveyor 2 is coated with electrostatic powder paint sprayed from the coating machine 4 as it passes through the coating booth 3, and uncoated powder paint is removed. is exhaust duct 55
The powder paint is carried by the air flow inside the coating booth 3 due to the exhaust gas from the exhaust gas, and is separated into the exhaust gas and the powder paint on the surface of the overmaterial 51, and the powder paint is deposited on the overmaterial 51.
The overfill material 51 is moved in the direction of the arrow by the drive device 54, and when the powder paint adhering to the overfill material 51 approaches the electric field curtain electrode 57, it is brushed off from the overfill material 51 by the electric field curtain action and painted. It falls onto the floor of the booth 3, is carried over the electric field panel 6 on the floor, and is collected and recovered by the recovery machine 7.
The collected powder paint is transferred to the coating machine 4 through a hose 8.
can be supplied and reused.

In this way, according to the present invention, the powder paint over-sprayed by the paint sprayer is continuously and immediately collected, so that the collected paint does not aggregate, and there is less dust contamination. Recovered paint can be effectively reused. Further, when changing colors, cleaning is easy because the number of electrodes is small, and replacing the overfill material is also easy, and colors can be easily changed without color mixing. Furthermore, since there is no change in the amount of exhaust air inside the paint booth during operation, there is no deterioration of the working environment, and there are many advantages such as easy replacement of electrodes.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the painting booth of the present invention, FIG.
Figure 4 is a partial plan cross-sectional view of this coating device, Figure 4 is an explanatory diagram of the principle of electric field curtain electrodes, and Figure 5 is a partially broken perspective view similar to Figure 1 showing another embodiment of the coating booth of the present invention. It is a diagram. In the figure, 2...Transfer conveyor, 3...Painting booth body, 4...Electrostatic powder coating machine, 5, 50...Powder passing device, 7...Powder recovery machine, 12, 55...Exhaust Duct, 14, 51... Excess material, 21, 54...
... Drive device, 25, 27 ... Electric field curtain electrode,
28...Power supply.

Claims (1)

[Scope of Claims] 1. A coating booth body provided with an electrostatic powder coating machine so that coating is carried out when objects to be coated supported by a transfer conveyor pass, and an electrostatic powder coating inside the coating booth body. A drive-type overfill is installed to face the coating machine and is driven to rotate, an exhaust duct is provided to exhaust the hollow part formed by the overfill, and a part is installed near the dust side of the overfill. a powder passing device comprising: an electrode for forming an electric field curtain; a drive device that drivably supports the overfill material in order to cause relative movement between the overfill material and the electrode; and a power source that applies voltage to the electrode. The uncoated powder coating inside the coating booth body, which is not applied to the object to be coated, is deposited on the surface of the coating material that is moved by the powder filtration device, and is collected by being brushed off by the electric field curtain formed by the electrode. A powder coating booth characterized by: