JP2008212863A - Coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating apparatus capable of forming a cylindrical swirling flow certainly enclosing coating material particles in a coating booth by a low flow rate of air, enhancing the coating efficiency thereby and preventing the coating material particles from sticking to the inner wall of the coating booth, reducing running costs, and improving a maintenance ability. <P>SOLUTION: An air feeding system (3S) forms a plurality of air feeding openings (6, ...) blowing air in a swirling direction of the swirling flow at predetermined intervals on a booth peripheral surface (2S) along its swirling direction and an air exhausting system (3E) forms an air exhausting opening exhausting air in the coating booth (2) to at least the bottom part (2B) of the coating booth (2), in the coating apparatus (1) provided with the air feeding system (3S) forming the swirling flow swirling air to the surrounding of a material to be coated (W) along the booth peripheral surface around the coating material sprayed (2S) from a coating machine (T) arranged above the inside of the coating booth (2) toward the material to be coated (W) therebelow and the air exhausting system (3E). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, air is applied around the coating material along the peripheral wall surface of the booth around the coating material sprayed from the coating machine disposed above the coating booth toward the coating material disposed below. The present invention relates to a coating facility for coating while forming a swirling flow to swirl.

  When spraying paint (coating material) from a coating machine (coating machine) and applying it to an object to be coated, from the ceiling so that the oversprayed paint particles do not adhere to the peripheral wall of the painting booth (coating booth). A downflow that flows down toward the floor is formed, or a coating pattern is regulated by blowing shaping air from its tip so as to surround the paint particles sprayed from the coating machine.

  For downflow, reducing the air volume can reduce the running cost, but the paint particles tend to adhere to the surroundings, increasing the cleaning cost, and increasing the air volume makes the paint particles less likely to adhere to the surroundings. However, at the same time, the coating particles sprayed from the coating machine are forcibly discharged, so that there is a problem that the coating efficiency is lowered.

  As for shaping air, the running cost can be reduced by reducing the air volume, but the coating particles spread to the surroundings and the coating efficiency is lowered.If the air volume is increased, the air hitting the object to be coated The coating particles rise, and in this case as well, there arises a problem that the coating efficiency is lowered.

For this reason, the present applicant can apply coating while swirling the air around the object to be coated so that the paint particles are not scattered and adhere to the inner wall of the painting booth even when the shaping air is reduced. Proposed equipment.
JP-A-2005-87960

  This can be done by installing a fan for swirling flow at the air supply port formed in the ceiling or by connecting an exhaust duct in the tangential direction of the circular exhaust port formed on the floor. A swirling flow that surrounds the coating machine and the object to be coated is formed.

However, when we actually prototyped and tested such a paint booth, a swirl flow was formed in the vicinity of the air supply and exhaust ports, but the swirlability became weaker as the distance from the air supply and exhaust ports was increased. In the vicinity of the coating machine and the object to be coated, it was found that the flow was simply downflowing from top to bottom.
In addition, when the experiment was carried out by increasing the air volume of each fan, a swirl flow could be formed in the paint booth, but the swirl flow was strong in the center and weak in the periphery. Therefore, it has been difficult to form a cylindrical swirl that surrounds the coating machine and the object to be coated.

  Therefore, the present invention can form a cylindrical swirl flow that reliably encloses the coating material particles with a low air volume in the coating booth, whereby the coating material particles adhere to the inner wall of the coating booth. It is a technical problem to prevent and improve running costs and maintainability.

  In order to solve this problem, the present invention is arranged along a peripheral wall surface of a booth around a coating material sprayed from an applicator disposed in the upper part of the coating booth toward an object to be disposed in the lower part thereof. In a coating facility provided with an air supply system and an exhaust system that form a swirling flow for swirling air around an object to be coated, the air supply system has a plurality of air supply ports for blowing air in the swirling direction of the swirling flow. The exhaust system is formed at predetermined intervals on the peripheral wall surface of the booth along the turning direction, and the exhaust system is characterized in that an exhaust port for discharging the air in the coating booth is formed at least at the bottom of the coating booth.

According to the present invention, when the coating agent is sprayed from the coating machine disposed in the upper part of the coating booth toward the object to be coated in the lower part, the coating agent is formed at predetermined intervals along the peripheral wall surface of the coating booth. Since air is blown out in a swirling direction from a plurality of air supply slits and discharged from an exhaust port formed on the floor surface, in the coating booth, around the coating agent sprayed toward the object to be coated, A cylindrical swirling flow is formed while turning along the peripheral wall surface of the booth.
At this time, the swirl flow is weak in the central part of the coating booth and the swirl speed is slow, so that the coating material particles sprayed from the coating machine slowly swirls around the object to be coated, Opportunities increase and coating efficiency improves.
In addition, since the coating booth peripheral wall surface is covered with an air layer formed by a swirling air flow, even if paint particles sprayed from the coating machine are scattered toward the peripheral wall surface, the swirl flow adheres to the peripheral wall surface. At the same time, the swirl flow can be taken out and discharged from the exhaust port.
Therefore, it is possible to form a cylindrical swirl flow that reliably encloses the coating material particles in the coating booth with low air volume air, thereby preventing the coating material particles from adhering to the inner wall of the coating booth. Cost and maintainability can be improved.

  In this example, it is possible to form a cylindrical swirl flow that reliably encloses the coating material particles with low air volume in the coating booth, thereby improving the coating efficiency and applying the coating material particles to the inner wall of the coating booth. In order to achieve the problem of improving the running cost and maintainability, the sprayer is sprayed from the coating machine disposed above the coating booth toward the object to be coated. In a coating facility equipped with an air supply system and an exhaust system that form a swirling flow that swirls air around the coating material around the booth peripheral wall surface, the swirling flow swirls as an air supply system. A plurality of air supply ports for blowing air in the direction are formed at predetermined intervals on the peripheral wall surface of the booth along the turning direction, and an exhaust port for discharging the air in the coating booth is formed at least at the bottom of the coating booth as an exhaust system It was.

  FIG. 1 is a schematic explanatory view showing an example of a coating facility according to the present invention, FIG. 2 is an explanatory view showing an air supply slit formed in a coating booth, and FIG. 3 is an explanatory view showing an exhaust slit formed in a ceiling portion, FIG. 4 is an explanatory view showing a rectifying plate arranged in the air supply slit, FIG. 5 is an explanatory view schematically showing the force acting on the paint particles, and FIG. 6 is an explanatory view showing another embodiment of the coating booth. FIG. 7 is an explanatory view showing a specific example of the air volume adjusting means, and FIG. 8 is a flowchart showing a processing procedure.

  This example shows the case where a coating material is used as the coating material, and the coating equipment 1 is directed from the electrostatic coating machine (coating machine) T disposed above the coating booth 2 to the workpiece W disposed below it. An air supply system 3S and an exhaust system 3E that form a swirling flow for swirling air around the article to be coated W along the booth peripheral wall surface 2S are provided around the sprayed coating material.

The painting booth 2 has a peripheral wall surface 2S formed in a cylindrical shape, a ceiling portion 2T formed in a dome shape, and a painting robot R for controlling the position of the painting machine T attached to the center of the ceiling portion 2T. An electrostatic coating machine T is attached to the tip of the arm.
The bottom 2B of the painting booth 2 is formed in a funnel shape with a diameter decreasing downward, and an insulator 4 is interposed between the bottom 2B and the peripheral wall surface 2S. A voltage (for example, −40 to 60 kV) is applied, and the workpiece W and the bottom 2B are connected to the ground.

In the exhaust system 3S, a positive pressure air supply chamber 8 to which conditioned air is supplied from an air conditioner (not shown) is formed on the outer peripheral portion of the peripheral wall surface 2S, and the conditioned air in the air supply chamber 5 is painted. A plurality of air supply slits (air supply ports) 6 to be supplied into the booth 2 are provided.
The air supply slits 6 are formed at predetermined intervals on the booth peripheral wall surface 2S along the swirling direction so as to blow out air in the swirling direction of the swirling flow.
In this example, four steps 7 extending in the vertical direction are formed on the cylindrical peripheral wall surface 2S with the step surfaces 7a facing forward in the turning direction at predetermined intervals along the circumferential direction (equal intervals of 90 ° central angle). It is formed (see FIG. 2).
In addition, air supply slits 5 for blowing air in the turning direction (clockwise as viewed in FIG. 2) are formed on each stepped surface 7a, and each air supply slit 6 has air horizontally extending along the turning direction. Is arranged (see FIG. 4).

The exhaust system 3E includes an exhaust chamber 9 formed below the bottom 2B of the painting booth 2, and an exhaust port 10 formed at the lower end of the bottom 2B that is reduced in a funnel shape.
A water film is formed on the bottom 2B of the painting booth 2 by flowing water from the upper edge side so that the paint mist falling on the funnel-shaped inclined surface can be reliably captured.
When the water is dropped from the exhaust port 10 into the exhaust chamber 9, the paint mist and water are brought into gas-liquid contact by the venturi action of the exhaust port 10, and then the gas and liquid are separated in the exhaust chamber 9. Yes.

An exhaust chamber 11 is formed on both the ceiling 2T and the outside thereof, and the swirl flow above the booth out of the swirl flow blown out of the supply slits 6 and formed in the painting booth 2 is shown. A plurality of exhaust slits 12 are guided at predetermined intervals along the turning direction.
In this example, a step 13 extending in the vertical direction is formed on the ceiling portion 2T at a predetermined interval (equal interval of a central angle of 90 °) along the circumferential direction with the step surface 13a facing backward in the turning direction, and each step surface 13a. Are formed with exhaust slits 12 that open in the anti-turning direction (counterclockwise as viewed in FIG. 2).

  The exhaust chambers 9 and 11 are connected to an exhaust fan 16 via exhaust ducts 14 and 15, and a damper 17 is interposed in the exhaust duct 15 connected to the exhaust chamber 11 of the ceiling 2T. Yes.

The above is one configuration example of the present invention, and the operation thereof will be described next.
When the exhaust fan 16 is activated, the exhaust chambers 9 and 11 become negative pressure, so the air in the painting booth 2 is discharged from the exhaust slits 12 and the exhaust port 10, and the painting booth 2 becomes negative pressure and the air supply chamber 5. Through the supply slits 6 formed in the peripheral wall surface 2S, the conditioned air flows into the painting booth 2 so as to be sucked.

When the turning direction is viewed from above (see FIG. 2) and clockwise, each air supply slit 6 is provided on a step surface 7a formed in a clockwise direction and is opened in a clockwise direction. Therefore, the air flowing into the painting booth 2 from the air supply chamber 5 is blown out clockwise toward the painting booth 2.
Further, since the air supply slit 6 is provided with the rectifying plate 8, after the air is blown horizontally toward the inside of the coating booth 2, the air is exhausted from the exhaust port 10 of the bottom 2B or the ceiling 2T while turning. A flow toward the slit 12 is formed.

At this time, if the damper 17 interposed in the exhaust duct 14 connected to the upper exhaust chamber 12 is adjusted so that the exhaust air volume ratio discharged through the exhaust ducts 14 and 15 is, for example, about 1:10. Most of the air blown from the supply slit 6 to the painting booth 2 is discharged from the exhaust port 10 of the bottom 2B while turning.
Moreover, the air in the vicinity of the ceiling portion 2T is exhausted from the exhaust slit 9 formed in the ceiling portion 2T while turning in the same direction as the air flow directed downward.
Thus, an air layer that swirls and flows is formed on all surfaces of the ceiling surface 2T, the peripheral wall surface 2S, and the bottom surface 2B of the painting booth 2.

In this state, when a negative high voltage is applied to the coating machine T and the peripheral wall surface 2S, the coating object T and the bottom part 2B are set to the ground potential (opposite polarity), and the paint is sprayed from the coating machine T, the paint particles are grounded. Electrostatically applied to the workpiece W at the potential.
At this time, since the swirling air flow is weak in the central portion of the coating machine T and the turning speed is slow, the paint particles sprayed from the coating machine T slowly swirl around the coating object W, and the coating object W The time and opportunity for contact with the coating increases, and the coating efficiency is greatly improved.

Further, since the peripheral wall surface 2S of the painting booth chamber 2 is charged with the same polarity as the paint particles, the paint particles are difficult to adhere due to electrostatic repulsion, but the electrically neutral paint particles are scattered. Even if this happens, an air layer that swirls and flows is formed, so that the air flow can reliably prevent the coating particles from adhering to the peripheral wall surface 2S.
Also, if the top 2T is also maintained in the same polarity as the paint particles, the bottom 2B is maintained at the ground potential (opposite polarity), so the oversprayed paint particles will not rise toward the ceiling 2T, It falls toward the bottom 2B due to attractive force and electrostatic force, and is captured by a water film or rides on an airflow that flows down while turning, and is discharged from the exhaust port 10 to the outside of the painting booth 2.

FIG. 5 schematically shows the force acting on the paint particles.
When the paint particles P sprayed from the coating machine T reach the vicinity of the peripheral wall surface 2S, when the direction of the flow swirling along the peripheral wall surface 2S is represented by a circle, the force f ₁ directed in the tangential direction, and the coating booth 2 resultant force F ₀ for oblique downward force f ₂ from the bottom 2B center opening an exhaust port 10 caused by suction is applied obliquely inward downward.
Although the paint particles P is the direction of the centrifugal force f ₃ to approach the peripheral wall surface caused by turning, since the mass of the impact paint particles to the centrifugal force is very small, even considering its centrifugal force f _3, A resultant force F _{1 in a} direction away from the peripheral wall surface 2S acts on the paint particle P, and the paint particle P is unlikely to adhere to the peripheral wall surface 2S without charging the peripheral wall surface 2S to the same polarity as the paint particle P. I understand.

  Thus, according to this example, the cylindrical swirling flow that reliably encloses the paint particles with a relatively low air volume due to the differential pressure between the painting booth 2 and the air supply chamber 5 only by operating the exhaust fan 16. As a result, the coating particles can be prevented from adhering to the peripheral wall surface 2S of the painting booth 2, and the running cost and maintainability can be improved.

FIGS. 6-8 shows other embodiment of the coating equipment concerning this invention. Portions common to FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the coating equipment 21 of this example, air supply slits 22 are formed at the corners of the stepped surface 7a formed on the peripheral wall surface 2S of the coating booth 2 at intervals of 90 °, and the slits 22 extend approximately in the radial direction. Air is blown horizontally toward the turning direction at an angle of 45 °.

Further, the air supply slits 22 are provided with wind speed adjusting means 23 that stabilizes the swirl state by variably controlling the opening area thereof and adjusting the inflow speed to control the pressure in the painting booth 2 and the air supply chamber 5. A control signal is output from the control device 25 to the wind speed adjusting means 23 based on the detection signals of the pressure sensors 24A.
As shown in FIG. 7, the wind speed adjusting means 23 includes a shutter plate 27 that is advanced and retracted by an air cylinder 26, for example, and can adjust the opening area of the inlet 22 a of the air supply slit 22 in a stepless manner. .

FIG. 8 is a flowchart showing a processing procedure of the control device 25.
When the process is started, the detection signals from the pressure sensors 24A... Are averaged in step STP1 to calculate the pressure of the painting booth 2, and the pressure of the supply chamber 5 is measured by the pressure sensor 24B. Based on this, the differential pressure between the painting booth 2 and the air supply chamber 5 is measured.
In step STP2, the differential pressure / opening data conversion table 28 is referred to, and in step STP3, a control signal corresponding to the opening data is output to a drive device (not shown) of each air cylinder 26 to The opening area of the inlet 22a is adjusted.
In the differential pressure-opening data conversion table 28, opening data is set in advance so that air at a constant wind speed is blown out from the supply slit 22 in accordance with the differential pressure between the painting booth 2 and the supply chamber 5.
Next, in step STP4, a timer is started, and after a predetermined time has elapsed in consideration of the time lag, the process returns to step STP1 and the above-described processing is repeated.

For example, when a large workpiece W is carried into the painting booth 2, the pressure loss in the painting booth 2 increases, so that if the exhaust fan 16 is rotated at a constant rotational speed, the exhaust air volume decreases, and the painting booth The pressure in 2 changes to the plus side, and the differential pressure from the air supply chamber 5 decreases.
Thereby, if the wind speed of the air blown out from the air supply slit 22 is lowered and the swirl flow becomes too weak, the coating quality may be adversely affected.
In this case, since the optimum opening data corresponding to the differential pressure is output and the opening 23a of the supply slit 22 is throttled, the wind speed is maintained constant, and the momentum of the air flow swirling in the painting booth 2 is also constant. Maintained, and thus the coating quality is maintained constant.

Further, when a small work W is loaded into the painting booth 2, the pressure loss in the painting booth 2 is reduced. Therefore, if the exhaust fan 16 is rotated at a constant rotational speed, the exhaust air volume increases and the painting booth is increased. The pressure in 2 changes to the minus side, and the differential pressure with the air supply chamber 5 increases.
As a result, if the wind speed of the air blown out from the air supply slit 22 increases and the swirl flow becomes too strong, the coating quality may be adversely affected.
In this case, optimum opening data corresponding to the differential pressure is output and the opening 23a of the supply slit 22 is widened, so that the wind speed is maintained constant and the momentum of the air flow swirling in the painting booth 2 is also maintained constant. As a result, the coating quality is kept constant.

In the above description, the case where the present invention is applied to a coating facility using a paint as a coating material has been described. However, the present invention is not limited to this, and an oil coating agent or an adhesive is used as a coating material to apply them to an object. It can also be applied to coating equipment.
In addition, when the thickness of the coating film is uneven depending on the swirling direction of air, such as a rectangular object to be coated, two coating booths with different swirling directions are provided in succession, and coating is performed in stages at each coating booth. The uneven thickness of the coating film can be offset.

In the above description, the case where the peripheral wall surface 2S is formed in a cylindrical shape as the coating booth 2 has been described. However, the present invention is not limited to this, and a swirling flow is generated around the object to be coated along the peripheral wall surface of the booth. As long as the shape can be formed, it can be formed into an arbitrary shape such as a cylindrical body having a substantially regular polygonal peripheral wall surface or an R-finished shape of the apex portion thereof.
Further, the air supply port is not limited to the air supply slit 6, and a number of air supply nozzles may be described in parallel along the circumferential wall longitudinal direction.

  As described above, the present invention can be applied to the application of an application booth that performs coating on an object to be coated in a state in which a swirling air flow is formed in the application booth.

Schematic explanatory drawing which shows an example of the booth for application | coating which concerns on this invention. Explanatory drawing which shows the air supply slit formed in the application | coating booth. Explanatory drawing which shows the exhaust slit formed in the ceiling part. Explanatory drawing which shows the baffle plate distribute | arranged to the air supply slit. Explanatory drawing which shows typically the force which acts on coating-material particle | grains. Explanatory drawing which shows other embodiment of the booth for application | coating. Explanatory drawing which shows the specific example of the air volume adjustment means. The flowchart which shows a process sequence.

Explanation of symbols

1 coating equipment 2 coating booth 2S booth peripheral wall surface 2T ceiling 2B bottom T electrostatic coating machine (coating machine)
W
3S Air supply system 3E Exhaust system 4 Insulator 5 Air supply chamber 6 Air supply slit (Air supply port)
8 Rectification plate 9 Exhaust chamber 10 Exhaust port 11 Exhaust chamber 12 Exhaust slit

Claims (8)

A swirl flow that swirls air around the coating material around the coating material sprayed from the coating machine disposed above the coating booth toward the coating material disposed below the coating booth. In a coating facility equipped with an air supply system and an exhaust system to form
In the air supply system, a plurality of air supply ports for blowing air in the swirling direction of the swirling flow are formed at predetermined intervals on the peripheral wall surface of the booth along the swirling direction,
The exhaust system has an exhaust port for discharging air in the coating booth at least at the bottom of the coating booth.   The coating equipment according to claim 1, wherein a bottom portion of the coating booth is formed in a funnel shape having a diameter reduced downward, and an exhaust port is formed on a lower end side thereof.   The coating facility according to claim 1, wherein the air supply port is an air supply slit formed in a booth peripheral wall surface and extending in a vertical direction.   The coating equipment according to claim 3, wherein a rectifying plate that blows air horizontally along the swirl direction is arranged in the air supply slit.   A plurality of exhaust slits for guiding the swirl flow above the booth to the outside of the swirl flow formed by blowing out from the air supply port are formed at predetermined intervals along the swirl direction in the ceiling portion of the coating booth. The coating equipment according to claim 1.   In the air supply system, an air supply chamber to which conditioned air is supplied is formed outside the peripheral wall surface of the coating booth, and the air supply chamber communicates with the booth through the air supply port. The coating equipment according to claim 1, further comprising an exhaust fan that exhausts the air in the coating booth from the exhaust port to maintain a negative pressure in the coating booth compared to the air supply chamber.   The coating equipment according to claim 1, wherein an electrostatic coating machine is used as the coating machine, and at least a peripheral wall surface of the coating booth is charged with the same polarity as the paint particles. The air supply system includes a wind speed controller for air blown from an air supply port, and a control device that controls the air speed controller based on a detection signal of a pressure sensor that detects a pressure in a coating booth. The coating equipment according to 1.

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