JPS5889961A - High speed rotary atomizer for electrostatic painting - Google Patents

Abstract

PURPOSE:To distribute paint uniformly over the entire circumference at the paint atomizing and releasing end of a rotating body, and to supply the paint even when the rotating body is rotated at a high speed, by providing knurled grooves for uniform distribution of the paint on the outside circumferential surface of an annular paint flow passage. CONSTITUTION:An inside circumferential surface 19 for guiding paint in the form of thin films and an annular paint well 21 for storage of the paint are connected by means of an annular paint flow passage 22 to a circumferential preceding end 20 for the purpose of atomizing and discharging liquid paint. Knurled grooves 24 for uniform distribution of the paint is provided on the outside circumferential surface of the passage 22. In other words, in the case of rotating a rotating body at a high speed, the paint is supplied by distributing the same uniformly and evenly over the entire circumference at the paint atomizing and releasing end edge of the rotating body, by which atomizing patterns substantially close to a true circle are formed without unevenness and deviation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-speed rotary atomizer for electrostatic coating, and more specifically, the present invention relates to a high-speed rotary atomizer for electrostatic coating, and more specifically, even when the rotary body is rotated at a high speed, liquid is generated all around the paint atomization discharge edge of the rotary body. The present invention relates to a high-speed rotary atomizer for electrostatic coating, which is capable of supplying paint in an even and uniform distribution and forming an atomization pattern (painting pattern) that is substantially perfectly circular without bias.

Conventionally, as a method of electrostatically atomizing liquid paint, paint is supplied inside a rotating body, the supplied paint is spread in a thin film along the inner peripheral surface of the rotating body, and this paint is applied to the rotating body. A method of atomizing and discharging from a tip provided on a circumferential edge is known.

In this electrostatic atomizing means, when the rotational speed of the rotating body is low, such as several hundred to several thousand revolutions per minute, the paint is uniformly and evenly distributed toward the atomizing tip of the rotating body. Even if it can be supplied in the form of a thin film, if the rotational speed of the rotating body is set to a high speed such as 10,000 revolutions per minute, the paint will be uniformly spread over the entire circumferential surface of the rotating body from one paint supply position. This has the drawback that the atomization turns formed as a result are likely to be uneven or deviate considerably from a perfect circle.

Therefore, increasing the rotational speed of the rotating body increases the amount of paint atomized per unit time, which increases the amount of coating processing, and also reduces the amount of solvent used as liquid paint. This is also highly desirable from the standpoint of making it possible to use paints with reduced viscosity.

Therefore, it is an object of the present invention to supply paint evenly and uniformly over the entire circumference of the paint atomization discharge edge of the rotor even when the rotor is rotated at high speed, and to prevent uneven distribution of the paint from K. To provide a rotary atomizer for electrostatic coating, which is capable of forming a substantially perfect circular atomization pattern without any deviation or bias.
be.

Another object of the present invention is that uniform distribution of liquid paint can be achieved with a relatively simple structure, and the paint dispensing mechanism will not be clogged even if the painting operation is stopped or foreign matter gets mixed into the paint. , K provides a rotary atomizer for electrostatic coating that is easy to clean and maintain, and also easy to manufacture.

According to the present invention, there is provided a circumferential tip for atomizing and discharging a liquid paint, an inner surface for guiding the paint in the form of a thin film to the tip, an annular paint reservoir for storing the paint, and the paint. comprising an annular paint flow path connecting the reservoir and the inner circumferential surface,
The present invention will be described in detail below with reference to the accompanying drawings, in which the present invention is characterized in that a knurled groove for uniformly distributing the paint is provided on the outer peripheral surface of the annular paint flow path.

In Figures 1 and 2 showing the overall arrangement of the electrostatic coating device, the coating device main body 1 is mounted on a bracket B at the tip of an electrically insulating support rod 2 that is movable up and down using a suitable lifting device (not shown). It is provided so as to be rotatable around the fulcrum 4.

This coating device body 1 is equipped with an air motor 6 housed inside a housing 5, and an atomizing device 1e (II rotating body) 8
is fixed by a fastening means such as a nut 9. The coating apparatus main body 1 is also provided with an air supply port 10 for driving and rotating the air motor 6 at high speed, and an exhaust port 11 for discharging this air. Furthermore,
The coating device main body 1VC is provided with a liquid paint supply port 12, and the liquid paint is atomized and rotated through a paint supply pipe 16 extending from the supply port 12 through the interior of the main body 1 to the rotating body 8. It is designed to be supplied into the body 8. Furthermore, the coating apparatus main body 1 is provided with a high voltage cable connection terminal 14, and although not shown, the high voltage from the high voltage generator is transmitted through the cable to the coating apparatus main body 1,
Therefore, it is applied to the atomizing rotating body 8. On the side of the housing 5 on which the rotating body is attached, a large number of injection holes 15 for shaping air, that is, pattern adjustment air, are arranged in an annular manner and are connected to an air supply port 16 .

In FIGS. 6 and 4, which show enlarged views of the atomizing rotary body 8, the rotary body 8 is fitted with gold J! External body 17 made of 4
It has the shape of a rotating body consisting of a metal inner body 18, an inner peripheral surface 19 for guiding liquid paint toward the tip in the form of a thin film, and a circumference for atomizing and discharging the paint. It has a shaped tip 20.

Furthermore, this rotating body 8 is equipped with the aforementioned paint supply pipe 16.
An annular paint reservoir 21 for temporarily storing the paint supplied from and uniformly supplying the paint over the entire circumference of the inner circumferential surface 19.
is formed, and this paint reservoir 21 and the inner peripheral surface 19
The outer body 17 and the inner body 18 are communicated with each other via a small-spaced annular slit-shaped channel 22 .

A high voltage is applied to the atomizing rotary body 8 via the cable connection terminal 14, and the air motor 6 is driven by the air supplied through the air supply port 10, and the atomizing rotary body 8 is accordingly driven. For example, s, o o o to 50,000 r
It is driven and rotated at a high speed such as P. The liquid paint is supplied to the paint reservoir 21 inside the rotating body 8 through the paint supply port 12 and the paint supply pipe 16, and is further supplied in the form of a thin film over the entire circumferential surface 19 of the rotor body through the annular flow path 22. . The paint on the inner circumferential surface 19 flows approximately axially forward through the atomizing rotating body, and is atomized and discharged from the circumferential tip 20 described above.

An important feature of the present invention is that the outer circumferential surface 26 of this annular flow path 22
When the knurled grooves 24 are provided over the entire surface, the knurled grooves 24 act as a distribution and smoothing mechanism for uniformly distributing the paint over the entire annular flow path 22 and smoothing the film thickness, and as a result, the rotation This is based on the fact that when the body is rotated at a high speed, it becomes possible to supply the paint evenly and evenly distributed over the entire circumference of the paint atomizing discharge edge 20 of the rotating body. .

First, the paint supplied into the rotating body 8 from the paint supply pipe 16 fills the paint reservoir 21, and then overflows to the inner peripheral surface 19 via the annular flow path 22, but if the rotational speed of the rotating body is high. In this case, non-uniformity of overflow from annular channel 22 tends to lead to non-uniformity of atomization from tip 20. That is, if the rotational speed of the rotating body is relatively low, (a)
The centrifugal force acting on the paint in the annular flow path 22 is small;
Therefore, since the paint outflow speed is relatively low, the paint reservoir 2
A sufficient amount of paint is stored over the entire circumference of the annular flow path 22, resulting in a uniform overflow of paint from the entire circumference of the annular flow path 22.
(b) Even if paint overflows from the HX-shaped channel 22 unevenly, the paint overflowing onto the inner circumferential surface 19 swamps on the inner circumferential surface 19 and is discharged from the tip 20 after flowing out. Therefore, the flow of paint on the inner circumferential surface 19 was made uniform, and the phenomenon that the atomization pattern became uneven was hardly observed.

On the other hand, when the rotational speed of the rotating body 8 is high, such as 10,000 revolutions per minute, the centrifugal force that acts as a paint trap in the annular flow path 22 is large (therefore, in this part Since the paint flow rate is also high, the paint flows into the annular flow path 2 before a sufficient amount of paint is stored around the entire circumference of the paint reservoir 21.
2, and as a result, the overflow from the annular flow path 22 becomes uneven. When the rotating body is rotating at high speed, the paint overflowing from the annular flow path 22 to the inner peripheral surface 191C is There is almost no flow along the circumferential surface 19 (because the paint flows straight toward the tip in the radial direction or rotation axis direction, uniform flow of paint on the inner circumferential surface 19 cannot be expected). For some reason, the non-uniformity of the overflow in the annular flow path 22 immediately appears as a deviation or disturbance in the atomization pattern. Generally, the outflow amount or discharge amount gradually increases from the paint supply position from 16 in the direction of rotation of the rotating body, and after this amount reaches a maximum, it gradually decreases again.

In the present invention, the knurled groove 24 provided on the outer circumferential surface 26 of the annular flow path 22 has a V-shaped flow rate adjustment orifice 25 and an inverted V-shaped weir 26 arranged alternately, thereby allowing the paint to flow smoothly. It allows a small amount of paint to flow out from a part of the reservoir 21'O, but it also functions as a weir to prevent paint from flowing out due to heavy snow, and also has a flow rate adjustment function. It is recognized that the function is to make the liquid level of 21 smooth and uniform, and to make at uniform over the entire circumference.

Moreover, according to the present invention, the effect of uniformly distributing the paint on the inner circumferential surface of the rotating body can be achieved by
Kyowa said that it was achieved with a simple structure of providing IiK knurling grooves, and that it was easy to manufacture.

Even if the painting operation is stopped or foreign matter gets mixed into the paint, no clogging will occur, and cleaning and maintenance are easy.

From the viewpoint of the above-mentioned effect, it is particularly desirable that the knurled grooves on the outer circumferential surface of the annular channel have a cape-tooth shape, as shown in the specific example of the crane drawing. The pitch of this knurled groove is 0.1 to 5yax, especially 0.2 to 1.5II
I+ range, and the groove depth is 0.1 to 5 inches,
In particular, a range of 0.2 to 1.5 sn is preferred for the purposes of the present invention. Of course, the knurled grooves can have any shape as long as they are regularly provided in large numbers over the entire outer circumferential surface of the annular flow path. Can take any shape.

It should also be understood that the rotating body 8 may have any shape other than the deeply constricted cup shown in the drawings, such as a shallow cup shape or a flat dish shape.

The atomizing device for electrostatic coating of the present invention has an atomizing rotating body of 5.00
0 to 50.000 rpm 1% to 8,000 to 50
．． It is used for painting by rotating at a high speed such as 000 rpm, and the voltage applied to the atomizing rotary body pressure +t20
It can be appropriately selected from the range of 160KV to 160KV, %[40 to 12Off.

The paint used can be any of those conventionally used for this type of electrostatic coating, such as epoxy paints, phenol paints, melamine paints, acrylic paints, organic solvent paints, or water-based paints, especially @ It can be advantageously applied to high viscosity paints that require a small amount of media, such as paints with a viscosity of 60 seconds or more (75 centiboise or more) using a 7-odd cup #4.

The amount of paint discharged, that is, the throughput amount varies considerably depending on the diameter of the open edge of the rotating body, the size of the notch, etc., but according to the present invention, the paint having the above-mentioned viscosity is used, and the outer diameter of the edge is 6011.
Even when the rotating body in 1 was used to electrostatically atomize paint into 700 equal parts, there was no unevenness or disturbance in the atomization pattern (1j! pattern), and it was close to a perfect circle. It was confirmed that the shape

[Brief explanation of the drawing]

1M is a partially sectional plan view of the entire electrostatic coating device, FIG. 2 is a side sectional view of the device in FIG. 1, FIG. 6 is a side sectional view of the atomization cup, and FIG. This is the front side 1 of the cup shown in the figure. Reference number 1 is the main body of the painting device, 6 is the motor, 8 is the rotating body, 13 is the paint supply pipe, 14 is the high voltage cable connection terminal, 19 is the inner peripheral surface, 20 is the circumferential tip, 21 is the paint reservoir, 22 26 is an annular flow path, 26 is an inner peripheral surface, 24 is a knurled groove, 25 is an open V-face, and 26 is a weir.

Claims (1)

[Claims] (1) A circumferential tip for atomizing and discharging liquid paint, an inner peripheral surface for guiding the paint in the form of a thin film to the tip, an annular paint reservoir for storing the paint, and a pattern paint reservoir. An annular paint flow path connected to the inner circumferential surface is provided, and an outer peripheral surface Kl! of the annular paint flow path is provided. A high-speed rotating atomizer for electrostatic coating, characterized by having a knurled scoop for uniformly distributing the material.