JP4095309B2 - Electrostatic paint supply equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating material supply apparatus suitable for supplying a conductive coating material represented by water-based, aqueous coating material, metallic coating material or the like to an electrostatic spray gun in electrostatic coating.
[0002]
[Prior art]
When conductive paint typified by water-based, water-based paint or metallic paint is used for electrostatic painting, the high voltage charged in the electrostatic spray gun leaks through the paint supply path, and the predetermined high voltage can be charged. The effect of electrostatic coating cannot be obtained. For this reason, a method is employed in which the entire coating material supply system is insulated from the ground potential, and the supply system itself is maintained at a high voltage to perform electrostatic coating.
[0003]
However, in this case, there is a problem of leakage through the conductive paint when the paint is replenished, so that the coating operation cannot be performed continuously. Therefore, as one method, a method of interrupting the painting operation for replenishing the paint and replenishing it during that time is taken. In the case of replenishment, the paint supply system is electrically connected to the ground potential, and is replenished from a paint replenishing device which is provided at the same ground potential. In this case, the painting work is forced to be interrupted, leaving problems in workability, painting efficiency, etc., and may not be adopted from the viewpoint of productivity.
[0004]
In another method, a method of supplying a paint intermittently with an interval capable of maintaining electrical insulation to a paint container during automatic paint replenishment to prevent leakage of a high voltage to the paint replenishment system may be used. . However, many of these methods use a device that supplies intermittently in the sealed supply path of the paint supply system, and it is difficult to secure a reliable insulation distance for controlling the supply time and amount, and it is stable depending on the supply conditions. There is a problem in reliability for continuous use.
[0005]
According to another method, a spare replenishment tank is provided for the paint container of the paint supply system so that the replenishment tank can be electrically connected to and disconnected from the ground potential. It is cut off from the paint supply system, and the replenishment of paint from the outside is stopped, and when refilling the paint container from the replenishment tank, it is cut off from the ground potential and connected to the paint supply system potential. Enables continuous supply of paint. In this case, the spare tank itself moves alternately between the paint supply side and the replenishment side, and the electrical connection with the paint supply path is repeated, thus leaving problems in operation reliability and stability.
[0006]
[Problems to be solved by the invention]
In the conventional devices as described above, each has its own problems, industrially increases productivity, and performs electrostatic coating continuously under stable conditions regardless of whether the spray gun is used or stopped. It was insufficient. An object of the present invention is to obtain a supply device that uses an open-type supply system with a pump that has high stability as a paint supply, and that can reliably maintain necessary insulation and enable electrostatic coating.
[0007]
Most of the above-mentioned methods use chambers and pressurized containers for supplying and replenishing paint, and there are difficulties in stable quantitative supply due to quantitative restrictions and changes in internal pressure, and in addition, the container is sealed. In particular, many problems remain, such as uncertain electrical interruption due to humidity when water-based paint is used.
[0008]
In particular, a pump as a stable paint supply device is used, and there is a demand for ease of handling and stability due to the certainty of replenishment and a simple configuration.
[0009]
[Means for solving problems]
In order to improve these conventional problems, the paint supply apparatus for electrostatic coating according to the present invention supplies the electrostatic coating gun with a supply system including a paint pump and a paint container insulated from the ground potential. , during replenishment system is a paint container of the supply system is arranged to supply nozzles out flow into the paint container atmospheric conditions to maintain the air insulating distance, electrical conduction and locking part is provided, the high voltage A control device is provided to control the high voltage charge to the electrostatic spray gun and the replenishment of paint so that either the interruption due to no charge or the high voltage interruption due to the paint supply stoppage is always present. It is what.
[0010]
Furthermore, if the electrostatic spray gun continues to be charged, a second electrical continuity that interrupts the high voltage by stopping the replenishment of paint is placed in series with the interrupting part , and either of the interrupting parts is The paint is supplied by cutting off the high voltage .
[0011]
In order to automatically supply continuously, the present invention detects the paint in the paint container by the level sensor, outputs a replenishment command at the lower limit value, outputs a replenishment stop command at the upper limit value, The paint supply from the pump is controlled.
Further, in order to perform electrical conduction and reliable shut-off of the shut-off portion, the present invention is provided with a purge air jetting means for blowing off the remaining paint when the supply of paint is stopped with respect to the supply nozzle.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows the configuration of a paint supply apparatus according to an embodiment of the present invention.
The electrostatic spray gun 1 is electrically connected to a high voltage generator 3 via a high voltage cable 2. Similarly, an atomizing air hose 4 is connected via a high voltage generator 3. When air is supplied by spraying, the high voltage is charged by the flow switch provided in the high voltage generator 3.
[0013]
The paint supplied to the electrostatic spray gun 1 is supplied by an electrostatic paint hose 5. The paint container 6 is provided in an insulated state from the ground potential, and is connected by a suction hose 8 to a paint pump 7 that is also provided in an insulated state from the bottom. The pump in this case is a pump generally used as a paint pump, such as an air-driven diaphragm pump.
[0014]
The paint pump 7 is supplied to the electrostatic spray gun 1 from the electrostatic paint hose 5 through the pressure reducing valve 9 at a stable paint pressure. The operation of the paint pump 7 is performed by compressed air, and the discharge pressure is controlled by the paint pressure reducing valve 9. The paint pressure reducing valve 9 may be controlled as an air operated type or may be controlled manually. Reference numeral 10 denotes a pressure gauge.
[0015]
The paint pump 7 is placed on an insulating table 11 and insulated from the ground potential with a sufficient distance. A leg voltage detecting means 12 and a ground switch 13 are provided on the leg portion of the insulating table 11 to feed back to the controller 14 and be used for confirmation of replenishment of paint.
[0016]
The replenishing nozzle 15 for replenishing the paint container 6 with the paint is maintained with an insulation distance from the paint container 6, and discharges the paint sent through the replenishment pump 16 and the paint valve 17 into the paint container 6. The replenishing nozzle 15 is provided with a purge air spraying means, and after the replenishment of the paint is stopped, the air is sprayed to eliminate the remaining paint and the incomplete insulation.
[0017]
Further, a level sensor 18 is also arranged for maintaining the insulation distance from the paint container 6 for detecting the remaining amount of the paint container 6. A detection signal from the level sensor 18 is sent to the controller 14, and a replenishment signal is output to the paint valve 17 at a preset lower limit value and a stop signal is output to the paint valve 17 at an upper limit value to control replenishment.
[0018]
The paint valve 17 is controlled so that it cannot be refilled by an interlock even when the electrostatic spray gun 1 is charged even under the refill conditions.
[0019]
The cover 20 protects the paint supply system and sets the above-described components in a predetermined arrangement. A necessary and sufficient insulation state is maintained by an air insulating layer in an atmospheric state with respect to each device of the paint supply system charged with an internal high voltage. In particular, the paint container 6 is not limited, but is made of resin. A resin cover is provided around the paint container 6, and external air can be distributed between the resin cover and the paint container 6 as an air insulating layer. .
[0020]
FIG. 2 shows an embodiment in which continuous replenishment is possible during charging of the electrostatic spray gun. The structure set in the cover 20 as a paint supply system as compared with FIG. 1 is added between the replenishment pumps 16, and the supply paint from the paint pump 7B is sent to the replenishment nozzle 15 from the electrostatic paint hose 5B. It is configured. Here, except that the paint valve 17 is provided immediately after the paint pump 7B, the structure is the same, and each is denoted by B.
[0021]
When electrostatic coating is performed using a conductive paint with the above configuration, the high voltage charged in the electrostatic spray gun is passed through the electrostatic paint hose to the paint supply system including the paint in the paint pump 7 and the paint container 6. Charged. However, there is no leakage of high voltage due to interruption of the ground potential by the insulating stand, and coating can be performed without impairing the electrostatic effect.
[0022]
When the paint in the paint container 6 decreases and reaches the lower limit value, the paint valve 17 is opened by the action of the level sensor 18, and the paint from the replenishment pump 16 is discharged from the replenishment nozzle 15 for replenishment. In this state, since a high-voltage leak occurs through the replenishing paint, the interlock is applied and charging to the electrostatic spray gun is stopped.
[0023]
If the electrostatic spray gun is still charged, for example, it is necessary to control not to replenish the connection with the ground potential, but control is performed based on the relationship between the remaining amount of paint in the container and the amount of work. The level and replenishment time are set so that there is no hindrance to painting work. On the other hand, in the present invention, since the control device is controlled so as to always shut off the high voltage by stopping the replenishment of paint or stopping the charging of the electrostatic spray gun, the spraying by the electrostatic spray gun is performed at the time of replenishing the paint. When the painting operation is performed, high voltage charging to the electrostatic spray gun is stopped and safety can be ensured.
[0024]
Further, when the painting operation is continued and the replenishment time cannot be set, as shown in the example of FIG. 2, a second replenishing device capable of cutting off from the ground potential is connected to the paint supply path, and the main paint container and the replenishment are replenished. Each paint valve is controlled to open and close so as to alternately supply paint to the paint container. In this way, by always maintaining the insulation state of either one, replenishment can be performed regardless of whether the electrostatic spray gun is charged or not.
[0025]
A sufficient insulation distance is secured between the replenishment nozzle 15 on the ground potential side and the paint in the paint container 6, and insulation is reliably maintained when replenishment is stopped, but the paint of the replenishment nozzle 15 is poorly cut. In some cases, insulation from the paint in the container may be impaired. In such a case, in the embodiment, insulation is surely obtained by eliminating excessive paint adhesion by compressed air from a purge air jet port provided around the nozzle.
[0026]
An embodiment of the supply nozzle 15 is shown in FIG. In this example, the purge air sent under the control of the controller 14 passes through the gap between the nozzle body 50 and the supply pipe 51 and is jetted around the paint nozzle 53 from the lower portion of the cap nut 52. The ejection port is not limited to the embodiment, and a configuration is employed that can perform ejection necessary to prevent the adhesion of the paint or to prevent the surrounding wall surfaces from being wet and dew condensation.
[0027]
Also, in the case where replenishment from the replenishment nozzle 15 during charging in FIG. 2 is caused by dispersion of discharged paint due to the discharge effect due to the charged high voltage, the paint container opened by effectively injecting purge air. It is possible to concentrate inside and perform stable replenishment.
[0028]
【The invention's effect】
As described above, according to the present invention, when a high voltage is charged and a conductive paint such as a water-based paint is electrostatically applied, an apparatus that automatically replenishes the paint can provide reliable insulation and stable supply. It is. According to this device , the electrostatic spray gun can maintain reliable insulation according to the usage condition, and even when continuously painting, high voltage leakage from the paint supply system can be prevented and workability is impaired. There is no.
[0029]
In addition, a pump that sucks and discharges paint in a container placed at atmospheric pressure can be used as a supply device, and stable discharge performance can be obtained, so that a wide range of paint conditions can be selected and paint quality can be maintained. The use restriction imposed on the conductive paint including the reliable insulation system can be eliminated.
[0030]
In particular, the insulation is impaired due to an increase in the humidity of the replenished portion of the water-based paint. By providing an air insulating layer that communicates with the outside air, it is possible to prevent insulation failure due to condensation or high humidity. Also, a simple configuration can be achieved without the need for temperature and humidity detection and adjustment devices.
[0031]
Furthermore, according to the present invention, since the paint air is supplied to the paint nozzle portion that needs to be replenished and maintain reliable insulation at the time of stoppage, discharge to unnecessary portions is prevented, and unnecessary paint adheres. -Reliable insulation can be obtained by eliminating accumulation.
[Brief description of the drawings]
FIG. 1 is a block diagram of a coating material supply apparatus showing an embodiment of the present invention. FIG. 2 is a block diagram of a coating material replenishment apparatus during charging according to another embodiment of the present invention. Diagram showing structural example [Explanation of symbols]
1. Electrostatic spray gun 3, high voltage generator 6, paint container 7, paint pump 11, insulating base 14, controller 15, replenishing nozzle 16, replenishing pump 17, paint valve 18, level sensor

Claims (3)

In an apparatus that automatically supplies paint to an electrostatic spray gun that charges high voltage and performs electrostatic coating, a paint pump connected to the electrostatic spray gun and insulated from the ground potential, and a suction port of the paint pump The paint container is connected to the paint container through the paint valve from the paint supply pump which is placed at atmospheric pressure and insulated from the earth potential, and is insulated from the earth potential. a supply nozzle and the supply and the paint container provided to maintain the air insulating distance, and level sensor provided to maintain the air insulating distance between sensing paint remaining in the paint container the paint container, high by charged stop to the supply nozzle and the blocking or electrostatic spray gun of the high voltage due to paint replenishment stop between the paint container of electrically conductive by coating efflux receives an output signal of said level sensor For electrostatic painting paint supply device provided with a controller for controlling such that any blocking of the blocking pressure is always performed 2. The electrostatic coating paint supply apparatus according to claim 1, wherein an apparatus comprising the paint container, the supply nozzle, and the level sensor is connected in series between the ground potential paint supply pump and the supply nozzle. The coating material supply apparatus for electrostatic coating which is provided in the structure and configured so that one of the insulating portions cuts off the high voltage. 3. A paint supply apparatus for electrostatic coating according to claim 1, further comprising purge air jetting means jetted when supply is stopped in the vicinity of the supply nozzle.

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