JP2003211035A - Method and apparatus for supplying powder in power coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably spray a powder coating material from a powder coating nozzle without pulsation and to form a coating film having a uniform thickness by supplying the powder coating material stably in a fixed quantity to the powder coating nozzle in a powder supply apparatus in the powder coating. <P>SOLUTION: The power coating material is stably supplied to the powder coating nozzle by supplying it to recessed parts such as grooves and holes formed on the circumference of a cylindrical column of a powder supply roller 16 from a powder layer 12 provided to be in contact with a part of the circumference of the powder supply roller 16 and to supply the powder coating material from the upper part of the powder supply roller by the rotation of the powder supply roller, and after that, taking out the powder coating material filled in the powder supply roller to supply to the powder coating nozzle by the flow of air flowing in a taking out part at a part of the circumference of the powder supply roller. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder supply device for supplying powder to a powder coating nozzle used for powder coating, and more particularly to an air supply device for supplying powder to the powder coating nozzle. The present invention relates to a powder supply device for supplying a certain amount of powder with high accuracy and stability to a powder injection nozzle.

[0002]

2. Description of the Related Art In recent years, there is an increasing demand for a coating method using a general toxic organic solvent that has been conventionally used due to environmental problems and a coating method that does not use a water-based coating containing a surfactant, and a solvent is required. As a result, there has been an increasing demand for powder coating that can collect and recycle powder that has not adhered to the substrate to be coated.

Compared with coating using a general solution, powder coating is difficult to supply a fixed amount of a coating nozzle, and as a method of supplying a fixed amount of powder to a powder coating nozzle conventionally used for powder coating. Generally, a method of feeding powder to a powder coating nozzle using a screw feeder is generally used.

As shown in FIG. 9, a screw feeder 40 is provided under the powder tank, and a powder pressure feeding section 26 for sending the powder to the powder coating nozzle by high pressure air utilizing the ejector phenomenon is provided under the screw feeder 40. , Powder feeding unit 26
Powder is supplied to the powder coating nozzle 20 by a (powder supply hose) connected to the powder supply pipe 28 connected to.

When the screw feeder 40 is rotated by the rotation of the motor 42, the powder is sent from the powder tank to the powder pressure-feeding section 26, and the high-pressure air jetted from the high-pressure air jetting nozzle 25 of the powder pressure-feeding section 26 is used. Screw feeder 4 due to the negative pressure generated by the ejector phenomenon
The powder coating nozzle 2 is sucked from the powder feeding unit 26 through the powder feeding unit 28 by the high pressure air from the powder pressure feeding unit 26.
0 is supplied with powder, and the powder sent to the powder coating nozzle 20 by the high voltage generator is ionized, and is sprayed on the base material which is also ionized with the opposite charge by the high voltage generator. The powder adheres to the powder, powder coating is performed, and the base material is heated to heat-melt the powder to form a coating film on the base material.

The amount of powder sprayed from the powder coating nozzle is controlled by the rotation speed of the screw 41 of the screw feeder 40, and a certain amount of powder is supplied to the powder coating nozzle 20 and sprayed from the powder spraying nozzle 20. It

[0007]

However, in the powder supply device of the powder coating device using the conventional screw feeder 40, the amount supplied from the powder supply device to the powder coating nozzle is measured, for example, in 1 minute. Occasionally, a fixed amount is supplied, but more and less parts are likely to appear due to the rotating part of the screw, so that the amount of powder sent from the powder supply device tends to change minutely and powder is sprayed from the powder injection nozzle. Pulsation of the powder jet occurs when the powder is sprayed, and there is a problem that coating unevenness is likely to occur especially when a thin uniform coating is desired, and there is no pulsation when the powder is supplied from the powder supply device to the powder coating nozzle. A stable powder supply device and supply method are desired.

[0008]

In order to solve the above-mentioned problems, in the powder supply apparatus for powder coating of the present invention, as shown in FIGS. 1 and 2, grooves, holes, etc. are formed on the circumference of the roller. A portion of the circumference of the powder supply roller 16 having a recess formed therein or the powder supply belt 6 having recesses such as grooves and holes formed on the surface of a flat belt or a belt such as a timing belt as shown in FIG. Then, the powder layer 12 and the powder supply roller 6 configured to supply the powder 5 to the powder supply roller or the powder supply belt are supplied by the air flow flowing on the circumference of the powder supply roller 6 or a part of the outer circumference of the powder supply belt. A belt driving roller for providing the powder supply roller 16 or a powder take-out section for taking out the powder from the powder supply belt 6 and rotating the powder supply roller 16 or driving the powder supply belt 6 by a rotating means such as a motor. 7 The powder of the powder layer is rotated to fill the concave portion of the powder supply roller or the concave portion of the powder supply belt, and the powder filled in the concave portion is taken out by the flow of the air flowing through the powder take-out section to form the powder coating nozzle. 20
By stably supplying a fixed amount of powder to the powder coating nozzle 20, stable powder coating without pulsation was made possible, and powder coating with a uniform film thickness became possible.

The recesses formed on the powder supply roller 16 and the powder supply belt 6 may have any shape such as a vertical groove shape, a horizontal groove shape, an oblique groove shape, a round hole shape, an elliptical hole shape, and a square hole shape. Alternatively, it suffices if a recess is formed on the belt so that the powder can be filled therein.

As a method for forming a flow of air flowing through the powder take-out portion for taking out the powder filled in the concave portion of the powder feed roller 16 or the powder feed belt 6, FIG. 1, FIG. 2, and FIG. 5 and 6, and a method of forming a flow of air flowing through the powder take-out portion by negative pressure due to an ejector phenomenon generated when high-pressure air is jetted from a high-pressure air jet nozzle as shown in FIGS. 4 and 5.
As shown in FIG. 8, high pressure air is supplied to the powder pressure tank and / or the powder supply device by a blower or a compressor to pressurize the inside of the powder supply device and flow from the inside of the powder supply device to the powder coating nozzle 20. There is a method of forming an air flow that flows through a part of the circumference of the powder supply roller 16 or a part of the surface of the powder supply belt 6 by the flow of air.

In order to make it easier for the powder to enter the recesses of the powder supply roller 16 or the powder supply belt 6, the powder tank 21 and / or the powder supply device 10 are vibrated by vibrating means such as a vibrator. Desirably, the rotation speed of the powder supply roller 16 and / or the size and depth of the recess of the powder supply roller are changed, or the powder supply belt 6 is changed.
It is possible to arbitrarily change the amount of powder supplied to the powder coating nozzle by changing the moving speed and the size and / or the depth of the recess of the powder supply belt.

By attaching a plurality of powder supply units to one powder supply roller 16 or powder supply belt 6 and connecting them to a plurality of powder coating nozzles 20, one powder supply device 10 can supply a plurality of powders. It becomes possible to supply the powder to the injection nozzle 20.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a powder supply method and a supply apparatus of the present invention will be described below with reference to the drawings.

FIGS. 1, 2 and 3 show a negative pressure due to an ejector phenomenon generated by injecting the high pressure air 1 from the high pressure air injection nozzle 25 of the powder pressure feeding section 26,
An air flow flowing through the powder take-out section 19 is formed.

When the powder supply roller 16 is rotated by a rotating means such as a motor, the powder of the powder layer 12 is filled in recesses such as grooves and holes formed on the outer periphery of the powder supply roller 16.

The high-pressure air jet nozzle 2 of the powder feeding section 26
When high-pressure air is jetted from 5, a negative pressure is generated because air is taken in from the surroundings by an ejector phenomenon, a negative pressure layer 15 is formed, and a powder take-out portion 19 that is a part of the outer periphery of the abrasive supply roller 16 is formed. The powder in the concave portion of the powder supply roller filled with the powder layer 12 is taken out by the flow of air flowing from the atmospheric pressure flowing through the negative pressure layer, and the powder pressure supply unit 26 supplies the powder supply pipe (powder supply hose) 28. Then, the powder is supplied to the powder coating nozzle 20 and is sprayed from the powder coating nozzle 20 to coat the base material with the powder.

In order to adjust the speed of the air for taking out the powder in the powder take-out section 19, a gap adjusting section 18 is provided,
It is desirable to increase the flow rate of air to make it easier to take out the powder from the concave portion of the powder supply roller 16 by narrowing the gap of the powder take-out portion 18 on the surface of the powder supply roller.

The amount of powder supplied to the powder coating nozzle 20 can be freely changed by arbitrarily changing the rotation speed of the powder supply roller 16 by a rotation speed changing means such as an inverter. .

By vibrating the powder tank 21 for supplying the powder to the powder supplying apparatus 10 and / or the powder supplying apparatus 10 by vibrating means such as a vibrator, the powder can easily enter the concave portion of the powder supplying roller. desirable.

In FIG. 7 as well, a method of forming a flow of air flowing through the powder take-out portion 19 by negative pressure due to an ejector phenomenon generated by injecting the high-pressure air 1 from the high-pressure air jet nozzle 25 of the powder feeding portion 26. However, the powder layer 12 is provided below the powder supply roller, and the powder is supplied at the powder layer below the powder supply roller by the flow of air between the powder supply roller 16 and the powder outlet 57. In the powder supply device, which takes out the powder filled in the roller concave portion and supplies the powder to the powder coating nozzle 20 through the powder supply pipe (powder supply hose) 28 in the powder pressure feeding part. In order to keep the height of the polishing material inside the powder supply device constant, an introduction pipe 51 is provided below the powder tank 21 and connected to the powder tank, and the powder is introduced by the height of the powder introduction port 54 of the introduction pipe 51. Powder layer in body feeding device Keeping the height of the face constant.

When the powder supply roller 16 is rotated by a driving force of a motor or the like, the powder layer 12 below the powder supply roller 16 is filled with powder in the recesses of the powder supply roller, and the powder pressure feeding section 26 is operated. Due to the negative pressure generated by the high pressure air jetted from the high pressure air jet nozzle 25,
The negative pressure layer 15 is formed in the vicinity of the powder extraction port 57 due to negative pressure with respect to the atmosphere, and flows from the atmosphere to the negative pressure layer 15 in the powder extraction port 57 through the powder supply roller 16 and the powder extraction port 57. The powder in the recess of the powder supply roller is taken out by the flow of air, and the powder is supplied from the powder take-out port 57 to the powder coating nozzle 20 from the powder pressure feeding section 26 through the powder supply pipe (powder supply hose). To be done.

Powder supply device 1 for powder from powder tank 21
The shape of the introduction pipe 51 to be introduced into 0 may be any shape such as a round shape, an elliptical shape, and a quadrangular shape, so that the powder layer surface 48 is below the upper end portion of the powder supply roller 16.
Adjust the position of 4.

FIG. 4 shows a powder supply device using a powder supply belt 6 in which recesses such as grooves and holes are formed on the belt surface such as a flat belt and a timing belt instead of the powder supply roller 16. The powder supply belt 6 is moved by rotating the belt drive roller 7 that drives the supply belt 6, and the powder filled in the powder layer 12 is taken out by the powder take-out unit 19 by the air flow. Painting nozzle 20
Is supplied to.

FIGS. 5 and 6 and 8 show a blower or powder blower in the powder pressure tank 22 and / or the powder feed apparatus 10 for forming a flow of air flowing around a part of the circumference of the powder feed roller 16. A part of the circumference of the powder supply roller or the surface of the powder supply belt is supplied by the high-pressure air supplied from the compressor to pressurize the inside of the powder supply device and the air flowing from the inside of the powder supply device to the powder coating nozzle 20. The air flow that flows through a part of
6, the powder in the powder tank 21 is supplied to the powder pressure tank 22 by opening the powder supply valve 24, and the powder supply valve 24 is used when the powder is sprayed from the powder coating nozzle 20. Is closed, and high pressure air is supplied to the powder pressure tank 22 and the powder supply device 10 to bring the inside of the powder pressure tank 22 and the powder supply device 10 into a pressurized state.

The powder supply device 10 and the powder pressure tank 22 are connected by the same pressure pipe 23, and the pressure is set to be almost the same, and the powder pressure tank 22 is connected to the powder layer 12 of the powder supply device 10. The powder is supplied, and the powder supply roller 16 is rotated by a rotating means such as a motor, so that the powder is filled from the powder layer 12 into the concave portion of the powder supply roller 16, and the high pressure air of the powder supply device 10 is supplied. High pressure layer 13
From the powder supply roller, a part of the outer circumference of the powder supply roller 19
Through the powder coating nozzle 20, and the powder in the recess of the powder supply roller is taken out by the powder take-out unit 19 by the flow of air, and the powder is supplied to the powder coating nozzle 20. Powder is sprayed and the equipment is powder coated.

In order to adjust the speed of the air for taking out the powder in the powder take-out section 19, a gap adjusting section 18 is provided,
It is desirable to narrow the gap flowing through the powder supply roller 16 to increase the flow rate of air so that the powder in the recess of the powder supply roller can be easily taken out.

FIG. 8 shows a powder supplying device 10 in which a powder layer is provided below the powder supplying device 10 and the powder is supplied from the powder layer to the powder supplying roller 16. The take-out portion 19 is set to almost the same pressure by the same pressure pipe 23, and the powder supply valve 24 installed at the upper part of the powder layer is opened to supply the powder from the powder tank 21 to the powder layer 12, and the powder supply valve Two
4 is closed and high-pressure air 1 is supplied into the powder supply device through the high-pressure air supply port 4 so that the inside of the powder supply device is in a pressurized state and the powder supply device 10 is supplied from the powder extraction port of the powder extraction unit. The powder filling the concave portion of the powder supply roller is taken out by the flow of air flowing from the powder coating nozzle 20 to the powder coating nozzle 20 and the powder coating is performed.

The amount of powder supplied to the powder coating nozzle 20 can be freely changed by arbitrarily changing the rotation speed of the powder supply roller 16 by means of a variable means such as an inverter.

By vibrating the powder tank 21 and / or the powder supply device 10 for supplying the powder to the powder supply device by vibrating means such as the vibrator 36, the powder can easily enter the concave portion of the powder supply roller. desirable.

Powder supply valve 24 when powder coating is stopped
The powder tank is opened to supply the powder to the powder layer 12.

In order to regularly supply the powder in the powder tank 21 while maintaining the pressure in the powder supply device 10, two powder pressure tanks 22 and a powder supply valve 24 are provided in series to alternately supply the powder. It is also possible to continuously supply the powder to the powder coating nozzle 20 for a long time by opening the body supply valve 24.

[0032]

Embodiments of the powder supply method and apparatus of the present invention described above will be specifically described below with reference to the drawings.

[First Embodiment] In FIG. 3, a powder tank 2 is used.
1 was charged with E-150BK14S, an epoxy-based powder coating material having an average particle size of 20 μm, manufactured by Toagosei Co., Ltd., and was vibrated by a vibrator 36 to supply the powder to the powder supplying device 10.
The powder supply roller 16 having a V-shaped vertical groove with a depth of 1 mm that is continuous on the surface of a Niro roller with an outer diameter of 150 mm is rotated, and high-pressure air with an inner diameter of 2 mm of the powder pressure feeding unit 26 is rotated. High pressure air 0.2 MPa from the injection nozzle 25
To supply the powder coating material to the powder coating nozzle 20,
Powder coating was applied to an iron plate as a work piece and heated at 150 ° C. to form a black epoxy resin film on the surface of the iron plate.

The gap between the gap adjusting portion 18 and the powder supply roller 16 was set to 0.2 mm, and powder coating was performed.

The powder that has not adhered to the iron plate is recovered by the cyclone 32 by using the negative pressure of the dust collector, sieved with a screen mesh, and the powder paint is returned to the powder tank 21 again. Powder coating was performed by spraying from a coating nozzle 20.

A uniform film having a thickness of about 200 μm was applied on the iron plate, and the powder sprayed from the powder spray nozzle 20 showed no pulsation and stable powder coating was performed.

[Embodiment 2] In FIGS. 5 and 6, an epoxy polyester powder coating E-350BK33C having an average particle diameter of 30 μm manufactured by Toagosei Co., Ltd. was placed in the powder tank, and a vibrator 36 was placed in the powder pressure tank 22. Gives vibration,
The powder supply valve 24 is opened to supply powder from the powder tank 21 to the powder pressure tank 22 and the powder supply device 10, and a nylon roller having an outer diameter of 150 mm and a screw shape having a depth of 0.8 mm is formed on the outer periphery of the roller. The powder supply roller 16 in which the groove is formed is rotated, the powder supply valve 24 is closed, and 0.02 MPa air is supplied to the powder supply device 10 and the powder pressure tank 22 using a blower, The powder was supplied to the coating nozzle 20 through a powder supply hose 28, sprayed with the powder coating material on the iron plate, and then heated to 150 ° C. to form a black coating film of epoxy polyester on the iron plate.

A uniform film having a thickness of about 350 μm was applied on the iron plate, and the powder sprayed from the powder coating nozzle 20 showed no pulsation, and stable powder coating was performed.

[0039]

INDUSTRIAL APPLICABILITY The present invention relates to a powder coating powder supply apparatus for supplying a uniform amount of powder to a powder coating nozzle in powder coating, and supplies powder using a conventional screw feeder. Recesses 1 formed on the powder supply roller to eliminate fine pulsation of the powder generated in the powder supply device.
Put the powder in 1 and rotate the powder supply roller 16, take out the powder filled in the powder supply roller by the flow of air flowing in a part of the outer periphery of the powder supply roller, and transfer the powder to the powder coating nozzle. By supplying it, it became possible to spray the powder coating material from the stable powder coating nozzle without pulsation.

[Brief description of drawings]

FIG. 1 is an explanatory view of a cross section showing an outline of a suction type powder supply device of the present invention.

FIG. 2 is a perspective view showing an outline of a suction type powder supply device of the present invention.

FIG. 3 is a side sectional view showing a suction type powder supply device according to an embodiment of the present invention.

FIG. 4 is a side sectional view showing a powder supply device using the belt of the embodiment of the present invention.

FIG. 5 is a side sectional view showing a pressure type powder supply device according to an embodiment of the present invention.

FIG. 6 is a perspective view showing a pressure type powder supply device according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view showing the outline of a suction type powder supply device having an abrasive layer at the bottom of the present invention.

FIG. 8 is a cross-sectional view showing an outline of a pressure type powder supply device having an abrasive layer at the bottom of the present invention.

FIG. 9 is an explanatory diagram of a powder supply device using a conventional screw feeder.

[Explanation of symbols]

1 high pressure air 3 Air flow 4 High pressure air supply port 5 powder 6 Powder supply belt 7 Belt drive roller 8 Powder supply roller recess 10 Powder feeder 12 powder layer 13 High pressure layer 14 Atmospheric pressure layer 15 Negative pressure layer 16 Powder supply roller 17 Powder collection port 18 Gap adjustment part 19 Powder take-out section 20 powder coating nozzle 21 powder tank 22 Abrasive pressure tank 23 Isobar 24 Powder supply valve 25 High pressure air injection nozzle 26 Powder pressure feeding section (Ejector section) 28 powder supply pipe (powder supply hose) 32 classifier (Cyclone) 36 vibrator 40 screw feeder 41 screw 42 motor 48 Powder layer surface 51 introduction tube 54 Powder inlet 55 Air layer 57 Powder outlet

Claims (10)

[Claims] 1. A powder supply device for supplying a fixed amount of powder to a powder coating nozzle in the powder coating in which powder is sprayed from a powder coating nozzle. To supply powder to the powder supply roller by making contact with a part of the circumference of the powder supply roller and the powder supply roller having recesses such as grooves and holes for supplying powder to the powder supply roller. In the powder coating, the powder layer and the powder supply roller are provided with a powder take-out section for taking out the powder supplied to the powder supply roller by a flow of air flowing through a part of the circumference of the powder supply roller. Powder feeder. 2. A powder supply device for supplying a certain amount of powder to a powder coating nozzle in powder coating in which powder is sprayed from a powder coating nozzle, such as a flat belt or a timing belt. The powder supply belt formed with recesses such as grooves and holes for supplying powder on the circumferential surface of the belt, so as to be in contact with a part of the circumference of the powder supply belt,
A powder layer for supplying powder to the powder supply belt and a powder take-out section for taking out the powder supplied to the powder supply belt by a flow of air flowing through a part of the circumference of the powder supply belt. A powder supply device for powder coating, characterized by being provided. 3. Powder coating in which powder is sprayed from a powder coating nozzle, and a method of supplying a fixed amount of powder to the nozzle is a powder in which recesses such as grooves and holes are formed on the circumference of a roller. By passing through the powder layer filled with the powder so that the powder is supplied so as to be in contact with a part of the circumference of the body supply roller, the powder is formed in the concave portion on the circumference of the powder supply roller. After feeding, after taking out the powder contained in the recesses such as grooves and holes formed on the circumference of the powder supply roller using the flow of air that flows through a part of the outer periphery of the powder supply roller, A powder supply method in powder coating, characterized in that the powder is supplied to a powder powder coating nozzle taken out from a recess of the powder supply roller. 4. In powder coating in which powder is sprayed from a powder coating nozzle, a groove and a hole are formed on the circumference of a belt such as a flat belt or a timing belt as a method of supplying a fixed amount of powder to the nozzle. The powder supply belt circle is formed by passing through the powder layer filled with the powder so that the powder supply belt is in contact with a part of the circumference of the powder supply belt formed with the recesses. After the powder was supplied to the recesses on the circumference, it entered into the recesses such as grooves and holes formed on the circumference of the powder supply belt by using the air flow flowing in a part of the outer circumference of the powder supply belt. A method for supplying powder in powder coating, which comprises extracting the powder and then supplying the powder to a powder powder coating nozzle taken out from a recess of the powder supply belt. 5. The powder supplying apparatus for powder coating according to claim 1 or 2, wherein the powder supplying roller or the powder is provided to form a flow of air flowing on a part of the circumference of the powder supplying roller. Between the body supply belt and the powder coating nozzle,
A powder pressure feeding unit having a high-pressure air injection nozzle is provided, and a negative pressure layer is provided in the powder supply device by the negative pressure generated by the ejector phenomenon generated by injecting high-pressure air from the high-pressure air injection nozzle. Powder in powder coating, characterized in that powder in the concave portion of the powder supply roller is taken out by the flow of air flowing in the negative pressure layer and the powder is supplied to the powder coating nozzle by injection of high pressure air in the powder feeding section. Supply device. 6. The powder supply apparatus for powder coating according to claim 1 or 2, wherein an air flow is formed which flows through a part of the circumference of the powder supply roller or the circumference of the powder supply belt. In order to pressurize the inside of the powder supply device by supplying high-pressure air with a blower or compressor to the powder pressure tank and / or powder supply device, the powder flows from the inside of the powder supply device to the powder coating nozzle. A powder supply device for powder coating, which forms an air flow flowing on a part of the circumference of the body supply roller or a part of the surface of the powder supply belt. 7. The powder supplying apparatus for powder coating according to claim 1 or 2, wherein the powder supplying roller or a belt driving roller of the powder supplying belt is rotated at a set rotational speed, A powder supply device for powder coating, wherein an arbitrary set amount of powder is supplied from a powder supply device to a powder coating nozzle. 8. The powder supplying apparatus for powder coating according to claim 1 or 2, wherein the speed of air for taking out the powder contained in the recess of the powder supply roller or the recess of the powder supply belt is adjusted. In order to make a gap adjustment part in parallel with the powder supply roller or powder supply belt in the part where the air flows on the outer periphery of the powder supply roller or powder supply belt, enter the concave part of the powder supply roller or the concave part of the powder supply belt. A powder supply device for powder coating, which is characterized in that the flow rate of air for taking out powder is adjusted. 9. The powder supplying apparatus for powder coating according to claim 1 or 2, wherein a powder supplying tank and / or a powder supplying tank is provided for filling the powder supplying roller recess or the powder supplying belt recess with the powder. A powder supply device in powder coating, characterized in that vibration is applied to the body supply device by a vibrator or the like. 10. The powder supply device for powder coating according to claim 1 or 2, wherein a plurality of powder take-out portions are provided for one powder supply roller or a powder supply belt, A powder supply apparatus for powder coating, wherein one powder supply apparatus is used to supply powder to a plurality of powder injection nozzles by supplying powder to a powder coating nozzle.