JP2000279857A - Method for preventing clogging of nozzle for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a prescribed coating process stably all the time by discharging remaining coating material by supplying a fluid to a nozzle inside at a prescribed pressure higher than the coating material jetting pressure at the time of coating immediately after completion of coating by spraying the coating material through the nozzle for coating. SOLUTION: A route unit 6 is fixed and joined on the upper face of a nozzle installation stand 2 while a coating material supply route 5 to a nozzle communicable with a curved coating material supply route 2b of the nozzle installation stand 2 being linearly formed in the up and down direction. A valve apparatus 9 having a needle valve 8 capable of adjusting the opening of the coating material supply route 2b is fixed and supported in a side face of such a route unit 6 through a bracket 7. When the travel of the needle valve 8 of the valve apparatus 9 is intermittently regulated to alter the supply pressure like pulses, a fluid is supplied to the inside of the nozzle 1 at a pressure higher than the coating material jetting pressure at the time of jetting to discharge and remove remaining coating materials (a), (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing clogging of a coating nozzle used for coating various building materials such as roofing materials.

[0002]

2. Description of the Related Art In a coating nozzle of this kind, when a predetermined coating is completed, the paint remaining in the nozzle solidifies and adheres to the inner surface of the nozzle, or flows down to the tip end of the nozzle hole by its own weight. As a result, the tip of the nozzle may hang down and solidify, which causes clogging of the paint during the next coating.

Conventionally, as a means for preventing such clogging of the paint, a method of cleaning the nozzle by rubbing the nozzle with a brush or the like after coating is completed, or a method of supplying a cleaning liquid such as water or alcohol to the nozzle to wash the nozzle is used to clean the nozzle. A method of removing the applied residual paint, or a method of coating the inner and outer surfaces of the nozzle with a resin material or the like to which paint does not easily adhere has been adopted.

[0004]

However, with the cleaning method using a brush or the like, it is difficult to clean the nozzle inner surface even though the outer surface and the tip edge of the nozzle can be cleaned neatly. Will occur. In addition, the method of cleaning using a cleaning liquid not only requires a cleaning liquid other than paint, but also removes the nozzle from the paint pipe to supply and pass the cleaning liquid to the nozzle,
A cleaning liquid supply device and a cleaning liquid pipe separate from the paint supply system are required, and a great deal of trouble and cost are required to prevent clogging. Further, in the coating method, there is a problem that the coating material is peeled off due to repetition of the coating, and the inside of the nozzle is more easily clogged after a short use.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to reliably remove residual paint inside a nozzle and at a tip portion which causes clogging without requiring special equipment and piping, and further, without requiring any manual operation. An object of the present invention is to provide a method for preventing clogging of a coating nozzle which can always perform coating with good stability.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method for preventing clogging of a coating nozzle according to the present invention comprises: It is characterized in that a fluid is supplied to the inside of the nozzle at a predetermined pressure higher than that of the nozzle to discharge the residual paint.

In the above-described structure, even if the paint flows under the pressure of the paint ejection, the viscosity of the paint is poor in the vicinity of the inner surface of the nozzle due to its viscosity, and the paint tends to solidify. Adheres to Since the paint ejection pressure is a relatively low pressure that is limited in accordance with the required supply amount of the paint, it is difficult to remove the paint adhered to the inner surface and the tip of the nozzle.

For this reason, immediately after the coating is completed, the fluid such as the paint itself or the air for ejecting the paint is supplied to the inside of the nozzle at a predetermined pressure larger than the paint ejection pressure at the time of painting, so that the fluid remains inside the nozzle. The paint and the paint that hangs easily at the tip of the nozzle are easily discharged and removed before solidification. Therefore,
It is possible to avoid coating defects such as a change in the thickness of the coating film due to clogging of the coating material during the next coating.

When the fluid used is the paint itself,
It is possible to respond simply by increasing the supply pressure of the paint without the need for a separate device configuration.Since the paint that easily solidifies on the inner surface of the nozzle is once removed by the above operation, it remains inside the nozzle after the operation. Depending on the paint to be applied, paint clogging does not occur at the next coating.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional front view of a main part of a coating apparatus to which a method for preventing clogging of a coating nozzle according to the present invention is applied. This coating apparatus A has a nozzle mounting base in which a concave portion 2a for fitting and holding the paint spray nozzle 1 is formed at a lower end portion, and a paint supply passage 2b connectable to the nozzle 1 is formed in a bent shape. A nozzle unit 12 comprising a lid member 4 removably fixed to the lower surface of the nozzle mounting base 2 via bolts 3 so that the nozzle 2 and the nozzle 1 can be replaced, and a communication connection with a bent paint supply passage 2b. A paint supply passage 5 to the possible nozzle 1 is formed linearly in the vertical direction and is fixedly connected to the upper surface of the nozzle mounting base 2, and is fixedly supported on a side surface of the passage unit 6 via a bracket 7. And a valve device 9 having a needle valve 8 capable of adjusting the opening degree of the paint supply passage 2b, and an air ejection passage 10 for ejecting air from around the nozzle 1 in the same direction as the paint ejection direction. And a pressure air connection unit 11 which is screwed connected to the side surface of the nozzle mounting base 2 to be connected.

A paint supply device 13 connected to the paint supply passage 5 of the passage unit 6 of the painting device A having the above-described basic configuration supplies paint to a paint tank (not shown and is omitted). An air compressor, such as a compressor, and a pump for pumping into the passage 5 are known (not shown because they are known). This paint supply device 13
Is configured to be freely adjustable via a regulator (not shown).

When ordinary coating is performed using the coating apparatus A having the above-described configuration, the opening of the coating supply passage 2b is appropriately adjusted through the needle valve 8, and the coating material of the passage unit 6 At the same time that the paint is supplied to the supply passage 5 and the pressurized air is supplied to the pressure air connection unit 11, a predetermined amount of the paint T is guided to the nozzle 1 through the passages 5 and 2b. At the same time as being sprayed toward the article to be coated at a predetermined ejection pressure, pressure air is ejected from the periphery of the nozzle 1 through the ejection passage 10 in the same direction as the paint T, whereby the paint is sprayed on the article to be coated. Then, a predetermined coating is performed.

When the predetermined coating is completed, the supply pressure of the coating material from the coating tank in the coating material supply device 13 is adjusted to a predetermined pressure higher than the ejection pressure at the time of coating by operating a regulator. Paint HA
Is supplied into the nozzle 1 through the passages 5 and 2b. The predetermined pressure is set in accordance with the viscosity of the paint, and is set to a value at which the paint having increased viscosity remaining near the inner surface of the nozzle 1 can be ejected.

As a result, immediately after the coating,
As shown in FIG. 3, the paint mass a remaining inside the nozzle 1 due to the increase in viscosity and the paint mass b hanging at the tip of the nozzle 1 are solidified and adhered to the inner surface or solidified. Before this, as shown in FIG. 3, it is discharged to the outside of the nozzle 1 and removed. Accordingly, it is possible to avoid the occurrence of coating defects such as a change in coating film thickness due to clogging of the nozzle 1 during the next coating.

Further, by using the coating material itself as a cleaning medium, a separate device such as a pipe for supplying a cleaning liquid is not required as in the prior art, and a nozzle using a device for coating is utilized. Can be cleaned. In the above embodiment, the supply pressure of the paint supplied to the inside of the nozzle 1 immediately after the completion of the coating is adjusted via the regulator as a means for making the supply pressure of the paint larger than the paint ejection pressure at the time of the coating. As described above, instead of this, even if a means for intermittently adjusting the opening of the needle valve 8 to change the supply pressure into a pulse shape is employed, the residual paints a and b are discharged and removed in the same manner as described above. It is possible to Also, as the fluid to be passed through the inside of the nozzle 1 immediately after coating, the pressure of the jetting air used at the time of coating can be used, and the jetting pressure is higher than at the time of coating, and the paint with increased viscosity can be jetted. With a predetermined pressure, it is possible to discharge paints a and b remaining at the time of painting.

If the residual paint in the nozzle 1 has such a viscosity that it flows down to the tip end side by its own weight, the fluid pressure passed through the nozzle 1 is 0.1 to 0.1.
The range of 0.3 MPa is optimal.

[0017]

As described above, according to the present invention, immediately after the completion of the predetermined coating, a fluid such as paint or air for jetting is supplied to the inside of the nozzle at a predetermined pressure higher than the paint jetting pressure at the time of coating. By doing so, the paint remaining inside the nozzle and the paint hanging at the tip of the nozzle are solidified and adhered to the inner surface or solidified without special equipment, piping, or even human labor. It is possible to reliably discharge and remove the waste before the waste.

Therefore, it is possible to always perform a predetermined coating stably while avoiding the occurrence of coating defects such as a change in coating film thickness due to clogging of the coating during the next coating.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of a main part of a coating apparatus to which a method for preventing clogging of a coating nozzle according to the present invention is applied.

FIG. 2 is a cross-sectional view illustrating a state of a nozzle immediately after the completion of coating before the clogging prevention method is performed.

FIG. 3 is a cross-sectional view illustrating a state of a nozzle after the clogging prevention method is performed.

[Explanation of symbols]

 1 Paint spray nozzles a, b Residual paint

Claims (1)

[Claims] The present invention is characterized in that a fluid is supplied into a nozzle at a predetermined pressure greater than a paint ejection pressure at the time of painting and a residual paint is discharged immediately after completion of painting by spraying paint from a painting nozzle. How to prevent nozzle clogging.