JP2010082586A - Powder feeding device and powder coating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the following problem of a conventional powder feeding device for electrostatic coating: adjustment of the feed rate of a driving air route of an air injector for sucking a power from a powder container and carrying the powder and adjustment of an air feed rate of a fluidizing air route for partially fluidizing the powder in the powder container have to be done independently of each other in the conventional powder feeding device for electrostatic coating. <P>SOLUTION: A fluidizing pad 38 for fluidizing the powder 53 is provided in the vicinity of a suction hole 35 of the air injector 34 for sucking the powder 53 in the powder container 25 and carrying the powder 53, and the fluidizing air route 46 for feeding compressed air to the fluidizing pad 38 is branched from the driving air route 41 for feeding compressed air to the air injector 34. Thus, the flow rate of the fluidizing air is automatically adjusted in interlock with adjustment of the driving air. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a powder supply apparatus in powder electrostatic coating and a powder coating apparatus using the powder supply apparatus.

  In powder electrostatic coating, a powder supply device for sucking powder from a powder container by a powder transport device such as an air injector or an air pump, and transporting the sucked powder directly to a powder coating gun, and the same are used. Conventionally, powder coating apparatuses are known (Patent Document 1, Patent Document 2).

  As the powder container, a plastic bag (plastic liner) or the like stored in an outer container such as a corrugated cardboard box or a corrugated cardboard box is used. The powder coating apparatus using such a simple powder container has an advantage that the color change time can be shortened because the powder container can be easily replaced at the time of color change.

  The conventional powder supply apparatus will be described with reference to FIG. 7 showing an air system. This apparatus includes a powder container 1 made of corrugated cardboard, a powder transfer device 4 such as an air injector provided with a suction unit 2 and a discharge unit 3, a suction tube 5 connected to the suction unit 2, A fluid member 7 provided in the vicinity of the suction port 6 of the suction pipe 5 is provided. The fluid member 7 is made of a porous material having air permeability.

  Further, as an air system, a drive air path 8 for supplying compressed air to the powder conveying device 4, a control air path 9, and a flowing air path 10 are provided. The flowing air path 10 is connected to the flowing air pipe 12 via the on-off valve 11. The fluid member 7 is attached to the lower end of the fluid air pipe 12.

  The drive air path 8, the control air path 9, and the flowing air path 10 are connected to a compressed air source 16 through pressure regulating valves 13, 14, and 15, respectively.

  A powder coating gun (not shown) is attached to the discharge part 3 of the powder conveying device 4 via a hose.

  When compressed air is supplied to the powder conveying device 4 through the drive air system path 8 and the control air path 9, the powder in the powder container 1 is sucked from the suction port 6 and discharged to the discharge unit 3. The charged powder is discharged from the powder coating gun connected to the discharge unit 3 to the object to be coated.

In this case, when a lump of powder enters the suction port 6, the lump of powder closes the suction port 6 to cause intermittent discharge (so-called breathing) of the powder coating material, and the powder on the coating surface. It causes a small lump of paint (so-called lumps). In order to prevent this, fluid air is ejected from the fluid member 7 to fluidize the powder in the vicinity of the suction port 6 so that no lump of powder is generated.
JP-A-4-226215 JP-A-5-329406

  In the conventional powder coating apparatus, when the discharge amount of the powder paint is changed according to the size, shape, etc. of the object to be coated, the supply amount of drive air is adjusted by operating the pressure regulating valve 13. If the amount of discharge from the powder coating gun increases due to this adjustment, there is a risk that the coating surface will be fuzzy or the breathing of the discharge will occur, resulting in poor coating.

  For this reason, it is necessary to adjust the amount of flowing air ejected from the fluid member 7 into the powder so as to be an optimum amount of fluid air corresponding to the amount of powder discharged by operating the pressure regulating valve 15.

  As described above, in the conventional powder coating apparatus, there is an inconvenience that the flowing air amount must be adjusted each time the supply amount of driving air (that is, the discharge amount of powder) is adjusted.

  Accordingly, the present invention relates to a powder supply device and a powder coating apparatus using the same, in which the adjustment of the flowing air is unnecessary by linking the supply amount of the flowing air with the adjustment of the supply amount of the driving air. The issue is to provide.

  In order to solve the above-mentioned problems, a powder supply apparatus according to the present invention includes a powder container, a powder transport apparatus that sucks and transports powder in the powder container, and a suction port of the powder transport apparatus In the powder supply apparatus, comprising: a flow member for flowing powder in the vicinity; a drive air path for supplying compressed air to the powder conveying apparatus; and a flow air path for supplying compressed air to the flow member. A configuration is adopted in which an air path is branched from the driving air path.

  A configuration in which a throttle valve is interposed in the fluid air path branched from the drive air path can be employed.

  Further, the powder conveying device, the flow member, and a part of the air path attached to each of the powder conveying device, the lifting cylinder are integrally provided, and the lifting cylinder is supported so as to be movable up and down with respect to the apparatus main body. Can be taken.

  It is possible to adopt a configuration in which the powder container is mounted on a vibration table provided with a vibration device.

  The elevating cylinder is constituted by a suction tube connected to a suction part of the powder conveying device, the suction port is provided at the lower end of the suction tube, the powder conveying device is provided at the upper end, and the suction tube It is possible to adopt a configuration in which a fluid air path is inserted and the fluid member is attached to a lower end portion of the fluid air path exposed from the suction port.

  An elevating head is provided at the lower end of the elevating cylinder, the powder conveying device is provided inside the elevating head, and a suction port that communicates with the elevating head to the suction unit and the discharge unit of the powder conveying device, respectively. And a discharge port, the flow member is attached to an opening provided in the vicinity of the suction port of the lift head, and a discharge pipe connected to the discharge port is inserted into the lift cylinder. Can do.

  The powder conveying apparatus can take a configuration that is an air injector.

  Moreover, the powder coating apparatus which solves the said subject is comprised by the powder supply apparatus provided with each above-mentioned structure, and the powder coating gun connected to the discharge part of the powder supply apparatus. .

  As a powder coating gun in this case, either a corona charging gun or a friction charging gun can be employed.

  According to the present invention, the flow air path for partially flowing the powder in the powder container is provided by branching from the drive air path for sucking and conveying the powder. When the supply amount of driving air is adjusted to change the discharge amount of the body, the supply amount of flowing air can be automatically adjusted to the optimum value in conjunction with the adjustment.

  In addition, the balance between the supply amount of the driving air and the supply amount of the flowing air is always maintained, so that the powder can be stably supplied.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for carrying out the present invention will be described below with reference to examples shown in the accompanying drawings.

  The embodiment 1 shown in FIGS. 1 to 3 shows a powder supply apparatus and a powder coating apparatus including the same. A vibration table 23 supported by a spring 22 is provided on the carriage 21, and a vibration device 24 is attached to the lower surface of the vibration table 23. A cardboard powder container 25 is placed on the vibration table 23. The powder may be stored directly in the powder container 25 or may be stored in a plastic bag (plastic liner) in the powder container 25.

  An apparatus main body 26 is fixed on the carriage 21, and a control panel 27 and a support arm 28 protruding horizontally are provided on the apparatus main body 26.

  A guide ring 29 is provided at an intermediate portion of the support arm 28, and a suction tube 31 is inserted into the guide ring 29 so as to be movable up and down. An adjustment screw 32 is screwed into the guide ring 29 in the radial direction (see FIG. 2), so that a required braking force is applied to the suction pipe 31.

  A support base 33 is provided at the upper end of the suction pipe 31, and a powder conveying device (in this embodiment, an air injector 34) is attached to the support base 33. The upper end of the suction pipe 31 passes through the support base 33 and communicates with the suction portion of the air injector 34. The lower end of the suction pipe 31 reaches the inside of the powder container 25. The open end at the lower end is the suction port 35.

  A fluid air pipe 37 is inserted into the suction pipe 31 with a margin, a lower end of the fluid air pipe 37 is exposed to the outside from the suction port 35, and a fluid pad 38 made of a breathable porous material is formed at the exposed lower end. Provided. The fluid pad 38 is located near the lower portion of the suction port 35.

  The upper end portion of the flowing air pipe 37 is drawn out of the suction pipe 31 at the portion of the support base 33.

  The combination of the suction pipe 31, the support base 33 provided at the upper end thereof, the air injector 34, the fluidized air pipe 37 and the fluidized pad 38 is referred to as an intake / exhaust set 40.

  Next, the air system will be described. As shown in FIGS. 1 and 3, a drive air path 41 and a control air path 42 are connected to predetermined ports of the air injector 34. These air paths 41 and 42 are connected to a compressed air source 45 via pressure regulating valves 43 and 44, respectively.

  Further, a flow air path 46 is provided that branches from the drive air path 41. The flowing air path 46 is connected to the flowing air pipe 37 through a throttle valve 47 and an on-off valve 48. As shown in FIG. 1, a corona charging type or friction charging type powder coating gun 52 is connected to the discharge portion 49 of the air injector 34 through a hose 51.

  In the above description, the portion excluding the hose 51 and the powder coating gun 52 is the powder supply apparatus referred to in the “Claims”, and the whole including the hose 51 and the powder coating gun 52 is powder coated. Device. In the “Claims”, the member generally called “elevating pipe” corresponds to the suction pipe 31 in the first embodiment.

  The first embodiment of the present invention is as described above, and the lower end portion of the suction pipe 31 of the suction / exhaust set 40 inserted through the guide ring 29 so as to freely move up and down is placed inside the powder 53 inside the powder container 25. Plug in. When the powder 53 is fluidized, the suction / discharge set 40 is adjusted in braking force by the adjusting screw 32 so as to gradually descend by its own weight.

  The pressure regulating valves 43 and 44 are adjusted in accordance with the object to be coated, and the on-off valve 48 is opened to form a flowing air path 46, and compressed air is supplied from the compressed air source 45 to these air paths. Further, in the flowing air path 46, the throttle valve 47 is operated to adjust the supply amount of the flowing air according to the state of the powder, the discharge amount of the powder, and the like.

  By operating the vibration device 24, the powder 53 in the powder container 25 placed on the vibration table 23 is fluidized as a whole, but the powder lump may not be pulverized.

  The small blob is pulverized by partial fluidization by the flowing air ejected from the fluid pad 38 in the vicinity of the suction port 35. For this reason, the powder is sucked smoothly without clogging the suction port 35 and discharged from the powder coating gun 52 to the object to be coated through the suction pipe 31, the air injector 34, its discharge part 49 and the hose 51. . As described above, since the small lump in the powder is pulverized by the compressed air ejected from the fluidized pad 38, so-called irregularities do not occur on the painted surface.

  When the powder 53 in the powder container 25 decreases as the coating progresses, the position of the fluidized portion also gradually lowers, and the suction / discharge set 40 descends by its own weight as it falls. The descending speed of the intake / exhaust set 40 is adjusted by the adjusting screw 32 of the guide ring 29 so as to coincide with the descending speed of the flow portion accompanying the decrease in powder.

  When the pressure adjustment valve 43 is operated to adjust the drive air amount and the discharge amount from the powder coating gun 52 is changed due to the change of the coating object, etc., the amount of flowing air is linked to this adjustment. Since it is adjusted at the same time, it is not necessary to independently adjust the supply amount of flowing air.

  The basic configuration of the powder supply device and the powder coating device of the second embodiment shown in FIGS. 4 and 5 is the same as that of the first embodiment. Since the difference is the portion of the intake / exhaust set 40, here, the intake / exhaust set 40 will be mainly described, and the other portions will be denoted by the same reference numerals and the description thereof will be omitted.

  The intake / exhaust set 40 in this case is composed of a lift pipe 54, a lift pipe head 55 provided at the lower end thereof, and a joint pipe 61 connected to the upper end of the lift pipe 54. Necessary members, which will be described later, are housed and integrated in the hoist pipe head 55. The elevating tube 54 is inserted through the guide ring 29 of the support arm 28 so as to be movable up and down.

  As shown in FIG. 5, the hoisting pipe head 55 is a case-like member that is integrally provided at the lower end of the hoisting pipe 54, and a tapered pad mounting portion 56 is provided outside the bottom wall 70 at the lower end. A suction port 57 is provided on the side surface. A fluid pad 59 is mounted on the pad mounting portion 56.

  An air injector 58 is installed inside the elevator pipe head 55, and an air duct 63 is provided between the suction port 57 and the suction part 62 of the air injector 58. Further, a discharge port 72 is provided in the partition wall 71 of the hoisting pipe head 55, and the discharge unit 64 of the air injector 58 and the discharge tube 65 are connected at the discharge port 72. The discharge pipe 65 is housed inside the lift pipe 54 and connected to the hose 51 in the joint pipe 61.

  A drive air path 66 and a control air path 67 are drawn into the lift pipe 54 from two ports provided in the joint pipe 61. These air paths 66 and 67 are further drawn into the hoist pipe head 55 and are connected to predetermined ports of the air injector 58, respectively.

  At the terminal portion of the drive air path 66, a branching air path 68 is provided. A throttle valve 69 is interposed in the middle of the flowing air path 68. The flowing air path 68 is connected to the flowing pad 59 by a joint 73 provided in a mounting hole of the bottom wall 70.

  The second embodiment is configured as described above. Similarly to the first embodiment, the compressed air is supplied to the air paths 66 and 67 while the vibration device 24 is operated to supply the powder 53 in the powder container 25. Are sucked and conveyed, and powder is discharged from the powder coating gun 52 onto the object to be coated.

  At this time, the flowing air is ejected from the fluid pad 59 through the fluid air passage 68 and the throttle valve 69 branched from the drive air passage 66. The powder in the vicinity of the suction port 57 is fluidized by the flowing air, and a small lump of powder is pulverized. In addition, according to the amount of powder discharged from the powder coating gun 52, the suction / discharge set 40 is lowered by its own weight, and the supply amount of fluid air is automatically linked with the adjustment of the supply amount of drive air. It is the same as that of the case of the said Example 1 that it is adjusted to.

[Experimental example]
The results of comparative experiments on the discharge stability and discharge amount between the conventional powder coating apparatus shown in the section “Background Art” and the powder coating apparatuses of Examples 1 and 2 are shown below.

1. Conventional Example Tables 1 and 2 show the measurement results of the air flow rate and the discharge amount in the case of the conventional example.

2. Examples 1 and 2
Tables 3 and 4 show the measurement results for the air flow rate and the discharge amount in Examples 1 and 2.

3. Comparison of discharge amount The discharge amount curve is shown in FIG.

4). Consideration of Experimental Results In the case of the conventional example, if the flow rate of air was kept constant and the discharge amount of the injector was increased, there was a case where a breathing state occurred and stable coating could not be performed. On the other hand, in the case of the first and second embodiments, the supply amount of the fluid air increases in association with the increase in the drive air supplied to the injector (increase in the powder discharge amount), and the discharge is almost proportional. The amount was stable, and the breathing state of the powder coating gun was not seen.

Partially omitted sectional view of the powder coating apparatus of Example 1 Partially enlarged sectional view of the above Air system diagram Partially omitted sectional view of the powder coating apparatus of Example 2 Partially enlarged sectional view of the above Graph showing discharge rate curve Air system diagram of conventional example

Explanation of symbols

21 Carriage 22 Spring 23 Shaking Table 24 Vibrating Device 25 Powder Container 28 Support Arm 29 Guide Ring 31 Suction Pipe 34 Air Injector 35 Suction Port 37 Fluid Air Pipe 38 Fluid Pad 40 Suction / Exhaust Set 41 Drive Air Path 42 Control Air Path 46 Fluid Air Route 47 Throttle valve 51 Hose 52 Powder coating gun 53 Powder 54 Elevator tube 55 Elevator tube head 57 Suction port 58 Air injector 59 Fluid pad 66 Drive air channel 68 Fluid air channel 69 Throttle valve

Claims (9)

A powder container, a powder conveying device for sucking and conveying the powder in the powder container, a fluid member for flowing powder in the vicinity of the suction port of the powder conveying device, and a compressed air in the powder conveying device In a powder supply apparatus comprising a driving air path for supplying compressed air and a flowing air path for supplying compressed air to the fluid member,
The powder supply apparatus, wherein the fluid air path is branched from the driving air path.   The powder supply apparatus according to claim 1, wherein a throttle valve is interposed in the flowing air path branched from the driving air path.   The powder conveying device, the flow member, and a part of the air path attached to each of the powder conveying device and the fluid member are each integrally provided in an elevating cylinder, and the elevating cylinder is supported to be movable up and down with respect to the apparatus main body. The powder supply apparatus according to claim 1 or 2.   The powder supply apparatus according to any one of claims 1 to 3, wherein the powder container is placed on a vibration table provided with a vibration device. The lifting cylinder is constituted by a suction pipe connected to the suction part of the powder conveying device,
The suction port is provided at the lower end of the suction tube, the powder conveying device is provided at the upper end, and the flowing air path is inserted through the suction tube,
The powder supply apparatus according to claim 3 or 4, wherein the fluid member is attached to a lower end portion of the fluid air path exposed from the suction port. A lifting tube head is provided at the lower end of the lifting tube, and the powder conveying device is provided inside the lifting tube head,
A suction port and a discharge port respectively connected to the suction unit and the discharge unit of the powder conveying device are provided in the hoisting pipe head;
The flow member is attached to an opening provided in the vicinity of the suction port of the lift pipe head,
The powder supply device according to any one of claims 3 to 5, wherein a discharge pipe connected to the discharge port is inserted into the elevating cylinder.   The powder supply apparatus according to any one of claims 1 to 6, wherein the powder conveying apparatus is an air injector.   8. A powder coating apparatus comprising: the powder supply apparatus according to claim 1; and a powder coating gun connected to a powder discharge unit of the powder supply apparatus.   9. The powder coating apparatus according to claim 8, wherein the powder coating gun is either a corona charging gun or a friction charging gun.

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