JPH06277571A - Rotary atomization type electrostatic coating machine - Google Patents

Abstract

PURPOSE:To reduce the washing fluid consumption by preventing the outflow of the washing fluid remaining in a washing passage and the intrusion of the fluid into a coating material at the time of ending washing. CONSTITUTION:This coating machine is provided with a check valve 45 which exists in the outflow port of the washing passage 24 and consists of a fixing part 45A fixed to an outer nozzle part 43A via a mounting nut 46, a cylindrical part 45B extending toward the front end side from this fixing part 45A and a cylindrical valve part 45C installed displaceably in a diametral direction on the front end side of the cylindrical part 45B, on the front end side of a feed tube 42. As a result, this check valve 45 opens to permit the outflow of the thinner in the washing passage 24 to the outside when the thinner is supplied into the washing passage 24 and the pressure is increased. On the other hand, the check valve 45 closes to close the outflow port of the washing passage 24 and prevents the outflow of the thinner in the washing passage 24 to the outside when the supply of the thinner stops and the pressure drops.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary atomizing type electrostatic coating machine suitable for coating an object to be coated such as a vehicle body and a refrigerator, and more particularly to a rotary atomizing type electrostatic coating machine having an outer cylinder and an inner cylinder. The present invention relates to a rotary atomization type electrostatic coating machine including a feed tube having a heavy cylinder structure.

[0002]

2. Description of the Related Art A rotary atomizing type electrostatic coating machine according to the prior art is shown in FIGS.

In the drawing, 1 is an electrostatic coating machine, 2 is a main body made of a metal and a resin, which constitutes the housing of the electrostatic coating machine 1, respectively, and an annular shape is provided on the tip side of the main body 2. The motor holder portion 2A is integrally formed, and a mounting bracket (not shown) is provided on the base end side. Further, the outer peripheral side of the main body 2 is covered with a main body cover 3, and the outer peripheral side of the main body cover 3 is charged with a paint having a low electric resistance value such as water-based paint or metallic paint (not shown).
Are provided so as to be spaced apart from each other in the circumferential direction.

Reference numeral 4 denotes a turbine type air motor attached to the motor holder portion 2A of the main body 2.
Is a shaft hole 5 bored in the axial direction, air bearings 6 provided so as to surround the shaft hole 5, and a turbine motor 7 provided at the base end side of the shaft hole 5. It is also configured as a compressed air bearing. Air is supplied to each air bearing 6 via a bearing air supply passage 8, and air is supplied to the turbine motor 7 via a drive air supply passage 9.

Reference numeral 10 denotes a hollow cylindrical rotary shaft which is inserted into the shaft hole 5. The rotary shaft 10 has a turbine motor 7 at its base end side.
Is fixed to the air motor 4, and the tip side thereof projects outside the air motor 4.
The rotating shaft 10 is rotatably driven while being supported by the air bearings 6 by the turbine motor 7.

11 is located outside the air motor 4 and is located on the rotary shaft 1.
0 is a bell-shaped rotary atomizing head fixed to the front end side of the rotary zero atomizing head 11. As shown in FIG. 10, the rotary atomizing head 11 is mounted such that one end side is attached to the rotary shaft 10 with an axially intermediate rim 11A interposed therebetween. The other end is a smoothing surface 11C that spreads like a bosh, and the tip end of the smoothing surface 11C is a discharge edge 11D in which a large number of V-shaped grooves are formed.

Reference numeral 12 denotes a hub member provided in the middle of the smoothing surface 11C of the rotary atomizing head 11, and the hub member 12 is
The back surface side is a convex conical paint supply surface 12 to which paint, thinner, etc. are selectively supplied from a feed tube 20 described later.
A, the paint from the paint supply surface 12A on the outer peripheral side,
A large number of first hub holes 12B for guiding the thinner to the discharge edge 11D side of the rotary atomizing head 11 are provided (only two are shown), and a central portion for supplying the thinner to the front side is provided. Two hub holes 12C are bored.

Reference numeral 13 denotes an inner air nozzle provided on the tip side of the main body 2 so as to surround the outer circumference of the rotary atomizing head 11, and 14
Indicates outer air nozzles provided outside the inner air nozzle 13, and the outer air nozzle 14 is screwed to the body cover 3 and the inner air nozzle 13 is attached to the body 2
It is sandwiched between. In addition, each of the air nozzles 13, 1
4, an annular air ejection hole 15 is formed. When the air from the shaping air supply passage 16 is supplied through the air chambers 17 and 18 to the air ejection hole 15, this air ejection hole 15 Rotating atomizing head 11 as shaping air
Of the paint sprayed from the rotary atomizing head 11 into a circular shape. Further, the rotary atomizing head 11 and the inner air nozzle 13
Another annular air ejection hole 19 is formed between and, and the air ejection hole 19 ejects a part of the air flowing out from each air bearing 6, the turbine motor 7, etc. as shaping air.

Reference numeral 20 denotes a feed tube coaxially provided in the rotary shaft 10, 21 denotes an outer cylinder which constitutes the feed tube 20 together with an inner cylinder 22 described later, and the outer cylinder 21 is
The base end side is attached to the main body 2, and the tip end side is reduced in diameter and extends to a position corresponding to the rim 11A of the rotary atomizing head 11 to form an outer nozzle portion 21A.

Reference numeral 22 denotes an inner cylinder coaxially arranged in the outer cylinder 21. The inner cylinder 22 has its base end side attached to the main body 2 and its front end side reduced in diameter to the outside of the outer cylinder 21. The inner nozzle portion 22A protrudes toward the inner nozzle portion 22A, and a valve seat 22B on which a valve body 25C of a trigger valve 25, which will be described later, is seated is provided on the base end side of the inner nozzle portion 22A.

Reference numeral 23 denotes a paint passage formed in the inner cylinder 22. The paint passage 23 is connected at its base end side to a paint supply pipe 32 described later, and at its tip end side, a paint supply surface 12A of the hub member 12. It opens towards. Further, a trigger valve 25 is provided in the middle of the paint passage 23, and the trigger valve 2
By being opened and closed by 5, the paint contained therein is ejected toward the hub member 12.

Reference numeral 24 denotes a cleaning passage formed between the outer cylinder 21 and the inner cylinder 22. The cleaning passage 24 has its base end side connected to a thinner supply pipe 35 described later, and its front end side has an inner cylinder 2
2 is open toward the tip side. Also, the cleaning passage 2
A tip side cleaning valve 26 described later is provided in the middle of 4, and the thinner supplied from the outside is injected toward the tip side of the inner cylinder 22 by being opened and closed by the tip side cleaning valve 26. Is.

Reference numeral 25 denotes a trigger valve composed of a 2-port 2-position air type switching valve. The trigger valve 25 is connected to an actuator 25A provided on the main body 2, a base end side thereof is connected to the actuator 25A, and a tip end side thereof is an inner cylinder. The valve shaft 25B is coaxially inserted into the valve 22, and a valve body 25C is provided on the tip end side of the valve shaft 25B and seats on and off the valve seat 22B of the inner cylinder 22. When the control air from the outside is supplied to and discharged from the actuator 25A, the trigger valve 25
The valve shaft 25B is expanded and contracted to move the valve body 25C to the valve seat 2 of the inner cylinder 22.
2B, the paint passage 23 is opened and closed.

Reference numeral 26 denotes a tip side cleaning valve consisting of a spring return type air type switching valve with 2 ports and 2 positions, and the tip side cleaning valve 26 is an actuator 2 provided in the main body 2.
6A and the proximal end side are connected to the actuator 26A,
The front end side includes a valve shaft 26B inserted into the cleaning passage 24, and a valve body 26C provided on the front end side of the valve shaft 26B and opening and closing the cleaning passage 24 in the middle thereof. And
The tip-side cleaning valve 26 is opened and closed by control air from the outside, thereby connecting and disconnecting a cleaning valve device 34 and a cleaning passage 24, which will be described later.

Further, in FIG. 11, 27 is a drainage passage formed in the main body 2 and one end of the drainage passage 27 is provided outside the electrostatic coating machine 1 through a drainage pipe 28. It is connected to the waste liquid tank 29, and the other end side is connected to the middle of the paint passage 23 in the main body 2.

Reference numeral 30 denotes a dump valve provided in the middle of the drainage passage 27, and the dump valve 30 is configured as a spring return type air type switching valve with two ports and two positions, similar to the tip side cleaning valve 26. ing. And the dump valve 3
Reference numeral 0 indicates that the drain passage 27 and the waste tank 29 are opened and closed by the control air from the outside so that the drain passage 27 and the waste tank 29 are communicated with each other and shut off.

Reference numeral 31 denotes a color changing valve device provided outside the electrostatic coating machine 1. The color changing valve device 31 is a paint supply pipe 3
2. A manifold 31A connected to the paint passage 23 via a gear pump 33, and a plurality of paint valves 31B, 31B (2 provided in the manifold 31A for discharging paints of different colors such as A color, B color, ... (Only one is shown), and a cleaning water valve 31 for discharging cleaning water, thinner, and air as cleaning fluid.
C, thinner valve 31D, and air valve 31E. The color change valve device 31 selectively supplies paint, cleaning water, thinner, and air into the paint passage 23.

Reference numeral 34 denotes the electrostatic coating machine 1 together with the color changing valve device 31.
2 shows a cleaning valve device provided outside the
Reference numeral 4 denotes a manifold 34A connected to the tip side cleaning valve 26 via a thinner supply pipe 35, and the manifold 34A.
And a thinner valve 34B that supplies thinner, and a manifold 34A that faces the thinner valve 34B and that is opened and closed by control air from the outside to provide a space between the thinner supply pipe 35 and the waste liquid tank 29. And a discharge valve 34C for connecting and disconnecting. Then, the cleaning valve device 34 supplies thinner into the cleaning passage 24 to clean the tip side of the inner nozzle portion 22A of the inner cylinder 22 at the time of color change cleaning, while the thinner remaining in the cleaning passage 24 will be described later. The ejector 36 of FIG.

Reference numeral 36 denotes an ejector which is provided between the cleaning valve device 34 and the waste liquid tank 29 and is connected to a discharge valve 34C of the cleaning valve device 34 through a discharge pipe 37. The ejector 36 is a main passage 36A. The thinner in the discharge pipe 37 is sucked by utilizing the pressure of a fluid such as air flowing toward the waste liquid tank 29, and the thinner is discharged into the waste liquid tank 29.

The rotary atomizing type electrostatic coating machine according to the prior art has the above-mentioned structure, and its operation will be described below with reference to FIG. 12, taking as an example the case where a water-based coating is used.

First, in the A color painting process, the color changing valve device 3 is used.
The A color paint valve 31B of No. 1 is used to discharge the A color paint, and the paint is supplied from the paint supply pipe 32 to the paint passage 23 and the rotary atomizing head 11, and the rotary shaft 10 and the rotary atomizing head 11 are driven by the air motor 4. Rotate at high speed. On the other hand, while applying a high voltage to the external electrode, shaping air is supplied from the shaping air supply passage 16 to eject the shaping air from the air ejection hole 15 to the front surface side of the rotary atomizing head 11.

Next, when the trigger valve 25 is opened, the A-colored paint in the paint passage 23 is removed from the paint supply surface 1 of the hub member 12.
It is discharged toward 2A and atomized by the high speed rotation of the rotary atomizing head 11. And this atomized A color paint is
While being charged while passing through the corona discharge area by the external electrode, a coating pattern is formed by the shaping air from the air ejection holes 15 and 19, and along the lines of electric force generated between the external electrode and the object to be coated. By flying, it is applied to the object to be coated.

Now, when one coating with the A color paint is completed, the paint adhering to the outer peripheral side of the inner nozzle portion 22A of the inner cylinder 22 is removed during an interval time T until the next A color coating process starts. Therefore, the first auxiliary cleaning is performed.

That is, the trigger valve 25 is closed, the tip side cleaning valve 26 is opened, and the thinner valve 34 of the cleaning valve device 34 is opened.
By discharging thinner from B into the thinner supply pipe 35 and supplying this thinner into the cleaning passage 24, the inner cylinder 22
The outer peripheral side of the inner nozzle portion 22A is partially washed.

Next, almost simultaneously with the end of the thinner discharge from the cleaning valve device 34, the discharge valve 34C is opened, and the ejector 3 is opened.
6 is activated. As a result, the thinner remaining in the cleaning passage 24 is removed by the tip side cleaning valve 26, the thinner supply pipe 35,
It is sucked into the ejector 36 through the discharge valve 34C and the discharge pipe 37, and is discharged from the ejector 36 into the waste liquid tank 29. Then, the tip side cleaning valve 26, the discharge valve 34C, and the ejector 36 are closed and stopped after a predetermined time t has elapsed from the time when the discharge of the thinner was completed from the thinner valve 34B of the cleaning valve device 34. Here, for the predetermined time t, only the thinner between the tip side (rotary atomizing head 11 side) of the washing passage 24 and the tip side washing valve 26 is discharged to the waste liquid tank 29, so that the leading edge of the washing passage 24 is discharged. The time required for the thinner located on the side to pass through the tip side cleaning valve 26 by the suction of the ejector 36 is set to be substantially equal.

When the A color coating process is completed and the next color paint, for example, the B color paint is sprayed, the A that remains or adheres to the paint supply pipe 32, the paint passage 23, the hub member 12, etc. Carry out a cleaning process to clean the color paint.

That is, in the cleaning process, after the dump valve 30 is opened to connect the drainage passage 27 and the waste liquid tank 29, the air valve 31E and the flush water valve 31C of the color change valve device 31 are used to feed air and flush water. By alternately discharging a plurality of times, the A-color paint remaining in the paint supply pipe 32, the paint passage 23, and the like is pushed into the waste liquid tank 29 from the drainage passage 27 through the drainage pipe 28 and the like. Then, when the cleaning of the paint passage 23 and the like is completed, the trigger valve 25 is opened while the dump valve 30 is open, and the thinner from the thinner valve 31D of the color changing valve device 31 is supplied into the paint passage 23. As a result, this thinner is jetted from the paint passage 23 to the paint supply surface 12A side of the hub member 12, and partially cleans the tip end side of the paint passage 23, the rotary atomizing head 11, the hub member 12, and the like.

Here, during coating, the paint is apt to adhere to the outer periphery of the tip of the inner nozzle portion 22A due to turbulent flow at the time of spraying the paint. In the above-mentioned cleaning process, the rotary atomizing head 11 is moved from the paint passage 23. Since the thinner or the like is only sprayed toward the nozzle, the attached paint cannot be washed.

Therefore, in the cleaning process, in addition to the main cleaning of the paint passage 23 and the like described above, in order to spotwise clean the outer peripheral side of the tip of the inner nozzle portion 22A, the second auxiliary cleaning is performed similarly to the first auxiliary cleaning. Perform auxiliary cleaning.

Further, when B color coating is performed after A color coating, the paint passage 23 and the drainage passage 2 from the B color paint valve 31B of the color change valve device 31 with the dump valve 30 opened.
By supplying the B color paint into the inside of 7, and then closing the dump valve 30 and opening the trigger valve 25 for a short time, the B color paint is supplied to the rotary atomizing head 11 to prepare for coating. After that, the coating of the object to be coated with color B is started.

[0031]

By the way, in the rotary atomizing type electrostatic coating machine according to the above-mentioned prior art, the cleaning passage 24 is provided to clean the outer peripheral side of the inner nozzle portion 22A of the inner cylinder 22.
In order to prevent the thinner supplied to the inside from mixing with the next color paint and degrading the coating quality, the thinner remaining in the cleaning passage 24 is sucked up to the tip side cleaning valve 26 by the ejector 36, and the waste liquid tank It is discharged into 29.

Therefore, according to the conventional technique, for example, about 20 cc of thinner is discharged from the cleaning passage 24 into the waste liquid tank 29 for each of the first and second auxiliary cleaning, so that only this amount is required every time. There is a problem that the thinner is wasted, the cleaning efficiency is significantly reduced, and the cleaning cost is increased.

Further, since the amount of thinner discharged into the waste liquid tank 29 is large, the surrounding environment is easily deteriorated, and at the time of each auxiliary cleaning, the portion of the cleaning passage 24 downstream of the tip side cleaning valve 26 (thinner is Since thinner must be newly filled in the extracted portion), there is a problem that a delay time is generated by this filling time and the response of the auxiliary cleaning is reduced. In particular, when painting a large amount of objects to be painted such as vehicle body painting and home electric appliance painting, since the number of washings is large, the cumulative amount of wasted thinner that is sucked by the ejector 36 and discarded in the waste liquid tank 29 is large, and the washing efficiency is large. , The surrounding environment is likely to drop significantly.

The present invention has been made in view of the above-mentioned problems of the prior art. At the end of cleaning, the cleaning fluid remaining in the cleaning passage is effectively prevented from being mixed into the coating material, and the cleaning fluid is effectively prevented. It is an object of the present invention to provide a rotary atomizing type electrostatic coating machine capable of significantly reducing the consumption amount of

[0035]

In order to solve the above-mentioned problems, the feature of the structure adopted by the present invention is that the cleaning fluid is discharged from the cleaning passage to the outside by constantly closing the valve on the outflow side of the cleaning passage. A check valve is provided to prevent the cleaning fluid from flowing out and open when the cleaning fluid is supplied to the cleaning passage to allow the cleaning fluid to flow to the outside.

The check valve is located radially outward from the fixed portion fixed to the outer tube of the feed tube and from the inner tube of the feed tube, and extends from the fixed portion toward the tip side. And a tubular portion located on the distal end side of the tubular portion and displaceable in the radial direction. Normally, the tubular portion is radially inwardly displaced and seated on the inner tube of the feed tube, and the cleaning fluid is introduced into the cleaning passage. It is preferably composed of a tubular valve portion that is displaced radially outward when supplied and is separated from the inner cylinder of the feed tube.

[0037]

[Function] When cleaning fluid is supplied to the cleaning passage during cleaning,
The check valve is opened to allow the cleaning fluid to flow out, and when the supply of the cleaning fluid to the cleaning passage is stopped, the check valve is closed to prevent the cleaning fluid from flowing out from the cleaning passage. Block.

Further, the check valve is located radially outward from the fixed portion fixed to the outer tube of the feed tube and from the inner tube of the feed tube, and extends from the fixed portion toward the tip side. The tubular portion and the distal end of the tubular portion are provided so as to be displaceable in the radial direction, and are normally displaced inward in the radial direction to be seated on the inner cylinder of the feed tube, and the cleaning fluid is supplied to the cleaning passage. If it is composed of a tubular valve portion that is displaced radially outward when separated from the inner tube of the feed tube,
When the cleaning fluid is supplied to the cleaning passage, the tubular valve portion is displaced radially outward to allow the cleaning fluid to flow out, and when the supply of the cleaning fluid to the cleaning passage is stopped, the cylindrical valve portion. Displaces radially inward to prevent wash fluid from flowing out of the wash passage.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technique shown in FIGS. 9 to 12 are designated by the same reference numerals, and the description thereof will be omitted.

First, FIGS. 1 to 6 relate to a first embodiment of the present invention, in which 41 is an electrostatic coating machine according to the present embodiment.
Reference numerals 42 denote feed tubes constituting a part of the electrostatic coating machine 41. The feed tube 42 has a tip end side that is reduced in diameter to form an outer nozzle portion 43A, which is similar to the feed tube 20 described in the related art. The outer cylinder 43 and the inner cylinder 44 provided coaxially with the outer cylinder 43 and having the inner nozzle portion 44A and the valve seat 44B are configured in a double cylinder shape. However, the feed tube 42 according to the present embodiment
Is provided with a check valve 45 to be described later, which is different from the one according to the related art.

Reference numeral 45 denotes a check valve which is located at the outlet of the cleaning passage 24 and is provided on the tip side of the feed tube 42 and is made of a fluororesin material. The check valve 45 is also shown in FIG. As shown, a fixing portion 45A provided on the tip side of the outer nozzle portion 43A of the outer cylinder 43 and detachably fixed via a mounting nut 46 and a radially separated portion from the inner nozzle portion 44A of the inner cylinder 44 are washed. The passage 24 is secured and the fixing portion 4
5A, a tubular portion 45B extending toward the tip side, and a thin-walled tapered tube that is provided on the tip side of the tubular portion 45B so as to be displaceable in the radial direction and is formed so as to gradually reduce in diameter toward the tip side. It is composed of a valve portion 45C. Further, the tubular valve portion 45C has elasticity and springiness, and its tip end side is urged radially inward to be seated on the outer peripheral side of the outer nozzle portion 43A of the outer cylinder 43 over the entire circumference. Thus, the outlet of the cleaning passage 24 is liquid-tightly sealed. Here, as shown in FIG. 2, the tip side of the tubular valve portion 45C faces the inner nozzle portion 44A of the inner cylinder 44, for example, 20 to 50.
Inclined by an angle α of about 30 degrees, preferably about 30 degrees,
This angle α causes the pressure of the thinner to act in the radial direction.

The check valve 45 is, as described later,
Normally, the tip side of the cylindrical valve portion 45C is seated on the outer peripheral side of the outer nozzle portion 43A of the outer cylinder 43 to seal the outlet of the cleaning passage 24, while the thinner is supplied into the cleaning passage 24 during cleaning. The cylindrical valve portion 45C is displaced radially outward by the pressure of the thinner, and the outlet of the cleaning passage 24 is opened.

Reference numeral 47 denotes a thinner source connected to the tip side cleaning valve 26 via the thinner supply pipe 35, and the thinner source 4
Reference numeral 7 supplies thinner as a cleaning fluid into the cleaning passage 24 through the thinner supply pipe 35 and the tip side cleaning valve 26.

The rotary atomizing type electrostatic coating machine according to the present embodiment has the above-mentioned construction, and its basic operation is not different from that of the prior art. Therefore, the cleaning process, which is a feature of this embodiment, will be described with reference to FIGS. 4 to 6.

First, when one coating with the A-color paint is completed, during the interval time T until the start of the next A-color coating process, the paint attached to the outer peripheral side of the inner nozzle portion 44A of the inner cylinder 44 is removed. In order to remove it, the first auxiliary cleaning is performed.

That is, when the trigger valve 25 is closed and the tip side cleaning valve 26 is opened, thinner from the thinner source 47 flows into the cleaning passage 24 through the thinner supply pipe 35 and the tip side cleaning valve 26. The pressure in the cleaning passage 24 rises according to the thinner pressure. As a result, as shown in FIG. 5, the tubular valve portion 45C of the check valve 45 is pushed outward in the radial direction and separated from the outer peripheral side of the inner nozzle portion 44A of the inner cylinder 44,
When the outlet of the cleaning passage 24 is opened, the thinner in the cleaning passage 24 is sprayed to the outside to clean the tip outer peripheral side of the inner nozzle portion 44A.

When the tip side cleaning valve 26 is closed,
The pressure in the cleaning passage 24 decreases, and as shown in FIG. 6, the cylindrical valve portion 45C of the check valve 45 returns inward in the radial direction due to its own elasticity and spring property, and the outer peripheral side of the inner nozzle portion 44A. Seated at and seal the outlet of the cleaning passage 24.

On the other hand, even during the color change cleaning from A color to B color,
Similar to the above-described first auxiliary cleaning, as the second auxiliary cleaning, the tip side cleaning valve 26 is opened to supply thinner into the cleaning passage 24 and the inner nozzle portion 44 of the inner cylinder 44.
Wash A.

Thus, according to this embodiment, the cleaning passage 2
4, the check valve 45 is provided on the tip side of the feed tube 42 located at the outflow port of No. 4, and therefore the tip side cleaning valve 26
When thinner is supplied from the cleaning passage 24 to the pressure rises, the check valve 45 opens to allow the thinner in the cleaning passage 24 to flow to the outside, while the thinner from the tip side cleaning valve 26 is released. When the supply of water is stopped and the pressure drops, the check valve 4
The valve 5 is closed to block the outlet of the cleaning passage 24, and the thinner in the cleaning passage 24 can be prevented from flowing out.

As a result, it is possible to effectively prevent the thinner in the cleaning passage 24 from leaking and mixing into the paint during the first and second auxiliary cleanings, and to greatly improve the coating quality and reliability. it can. Also, as described in the prior art, the cleaning passage 2
Since it is not necessary to suck the residual thinner in the nozzle 4 by the ejector 36 and dispose of it in the waste liquid tank 29, the thinner can be used efficiently, the cleaning efficiency can be improved and the cleaning cost can be reduced, and the cleaning valve device 34 and the ejector can be used. It is possible to eliminate 36 and the like.

That is, assuming that the amount of waste thinner per auxiliary cleaning is 20 cc and the cleaning is performed once per minute, the amount of waste thinner per hour is 1200 cc (= 20 × 6).
0) is reached, and if the daily coating time is 16 hours in a two-shift system, 19200 cc (= 20 × 60 × 8 × 2), that is, 1
Since it reaches 9 liters, this 19 liters of thinner can be saved.

Further, since almost all the thinner is used for cleaning and not discarded in the waste liquid tank 29, deterioration of the surrounding environment can be effectively prevented, and the delay time required for thinner filling can be eliminated to improve the responsiveness. You can

On the other hand, the check valve 45 is made of a fluorine resin material, and the mounting nut 4 is attached to the outer nozzle portion 43A of the outer cylinder 43.
6 and the fixing portion 45A fixed via the inner cylinder portion 44 and the fixing portion 45A, which are spaced radially outward from the inner cylinder 44, and the cleaning passage 24 is secured between the fixing portion 45A and the inner nozzle portion 44A. And a cylindrical valve portion 45C which is elastically and elastically provided on the distal end side of the tubular portion 45B so as to be displaceable in the radial direction.
4, the tubular valve portion 45C can be quickly seated on and off the inner nozzle portion 44A of the inner cylinder 44 by utilizing the elasticity of rubber to open and close the valve with good responsiveness. The manufacturing cost can be reduced by simplifying the structure.

Further, since the check valve 45 is detachably provided via the mounting nut 46, when the elastic force of the check valve 45 is lost due to deterioration over time, etc., the rotary atomizing head 11 and the mounting head are mounted. Just remove the nut 46, electrostatic coating machine 4
The check valve 45 can be easily replaced with a new one from the front side of 1, and the maintainability can be greatly improved.

Next, FIGS. 7 and 8 show a second embodiment of the present invention. The feature of this embodiment is that a flat seal portion is provided on the inner peripheral side of the cylindrical valve portion of the check valve. There is something. In the present embodiment, the same components as those in the first embodiment shown in FIGS. 1 to 6 are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 51 denotes a check valve applied to this embodiment in place of the check valve 45 described in the first embodiment,
The check valve 51 is made of a fluororesin material, and is substantially the same as the check valve 45 described in the first embodiment.
6, a fixing portion 51A detachably fixed to the outer nozzle portion 43A of the outer cylinder 43, a cylindrical portion 51B extending from the fixing portion 51A toward the distal end side, and a diameter at the distal end side of the cylindrical portion 51B. And a cylindrical valve portion 51C provided so as to be displaceable in the direction. However, as shown in FIG. 8, the inner cylinder 4 is provided on the inner peripheral side of the cylindrical valve portion 51C of the check valve 51 according to the present embodiment.
4 is integrally formed with a cylindrical seal surface 51D that is seated in a liquid-tight manner over the entire circumference on the inner nozzle portion 44A.
This is different from the check valve 45 according to the first embodiment.

Thus, the present embodiment having such a configuration can also achieve substantially the same actions and effects as those of the first embodiment described above, but in particular, in this embodiment, the tubular valve portion 51C Since the flat cylindrical sealing surface 51D is provided on the inner peripheral side, the check valve 51 can more reliably seal the outlet of the cleaning passage 24.

In the above embodiment, the check valves 45, 51 are
Although it has been described as being formed from a fluororesin material,
The present invention is not limited to this, and other resin materials may be used.

Further, in the above-mentioned embodiment, as the rotary atomizing type electrostatic coating machine, the coating machine using the bell type rotary atomizing head 11 is exemplified, but instead of this, a disk type rotary atomizing head is used. It can also be applied to the coating machine used.

Furthermore, in the above-mentioned embodiment, the case where the water-based paint is used has been described as an example, but the present invention is not limited to this, and a solvent-based paint may be used.

[0061]

As described above in detail, according to the present invention, a valve is always closed on the outflow side of the cleaning passage to prevent the cleaning fluid from flowing out from the cleaning passage to the cleaning passage. Since a check valve is provided that opens when the cleaning fluid is supplied and allows the cleaning fluid to flow to the outside, the cleaning fluid in the cleaning passage flows to the outside and mixes with the paint after the cleaning is completed. Can be effectively prevented, and the coating quality and reliability can be improved. In addition, the cleaning fluid can be efficiently used to reduce the cleaning cost, and the deterioration of the surrounding environment can be prevented.

Further, the check valve is located radially outward from the fixed portion fixed to the outer tube of the feed tube and the inner tube of the feed tube, and extends from the fixed portion toward the tip side. The tubular portion and the distal end of the tubular portion are provided so as to be displaceable in the radial direction, and are normally displaced inward in the radial direction to be seated on the inner cylinder of the feed tube, and the cleaning fluid is supplied to the cleaning passage. In this case, the tubular valve portion is displaced radially outward and is separated from the inner cylinder of the feed tube, so that the cylindrical valve portion is quickly separated from the inner cylinder according to the pressure in the cleaning passage. Thus, the valve can be opened and closed with good responsiveness, the overall structure can be simplified, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a main part of a rotary atomizing type electrostatic coating machine according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an enlarged check valve in FIG.

FIG. 3 is an overall configuration diagram of a coating system in which a rotary atomizing type electrostatic coating machine is used.

FIG. 4 is a time chart showing a painting process and a cleaning process.

FIG. 5 is an enlarged sectional view of an essential part showing a state in which a check valve is opened.

FIG. 6 is a sectional view similar to FIG. 5, showing a state in which the check valve is closed.

FIG. 7 is an enlarged sectional view showing a main part of a rotary atomizing type electrostatic coating machine according to a second embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view showing the check valve in FIG.

FIG. 9 is a cross-sectional view showing a main part of a rotary atomizing type electrostatic coating machine according to a conventional technique.

10 is a cross-sectional view showing an enlarged main part in FIG.

FIG. 11 is an overall configuration diagram of a coating system using a rotary atomizing type electrostatic coating machine according to a conventional technique.

FIG. 12 is a time chart showing a painting process and a cleaning process.

[Explanation of symbols]

 2 main body 4 air motor 10 rotating shaft 11 rotating atomizing head 23 paint passage 24 cleaning passage 42 feed tube 43 outer cylinder 44 inner cylinder 45,51 check valve 45A, 51A fixed part 45B, 51B cylindrical part 45C, 51C cylindrical valve part

Claims (2)

[Claims] 1. A cylindrical main body, an air motor provided on the main body, a rotary shaft that is inserted in the axial direction of the air motor and is rotated by the air motor, and a rotary shaft that is located outside the main body. A feed tube having a rotary atomizing head provided on the tip side, an outer tube and an inner tube coaxially provided on the rotating shaft, and a feed tube having a tip side extending into the rotary atomizing head, and the feed tube. And a cleaning passage which is formed between the outer cylinder and the inner cylinder of the feed tube and which is supplied with the cleaning fluid. In the rotary atomization type electrostatic coating machine,
The outflow side of the cleaning passage is normally closed to prevent the cleaning fluid from flowing out of the cleaning passage, and when the cleaning fluid is supplied to the cleaning passage, the valve is opened to allow the cleaning fluid to flow to the outside. A rotary atomization type electrostatic coating machine, which is equipped with a check valve that allows it to flow out to the. 2. The check valve is located radially outward from a fixing portion fixed to an outer cylinder of the feed tube and from an inner cylinder of the feed tube, and is directed from the fixing portion to a tip side. And a tubular portion which is extended and is disposed so as to be displaceable in the radial direction at the tip end side of the tubular portion, and is normally displaced inward in the radial direction to be seated on the inner cylinder of the feed tube and washed in the washing passage. The rotary atomizing electrostatic coating machine according to claim 1, wherein the rotary atomizing type electrostatic coating machine comprises a cylindrical valve portion which is displaced radially outward when supplied with a fluid and separates from an inner cylinder of the feed tube.