JPS6115740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nozzle device for a powder coating device for a fluorescent lamp, which coats the inner surface of a glass bulb of a fluorescent lamp with a fluorescent substance or a powder such as silica.

Conventionally, in the fluorescent lamp manufacturing process, in order to apply a phosphor to the inner surface of a glass bulb, a phosphor coating liquid was prepared by dispersing phosphor powder in a lacquer containing an organic binder dissolved in a solvent. The method used is to apply fluorophore to the inner surface of a glass tube and dry it to form a phosphor coating, and then heat and bake the bulb to burn off the organic binder remaining in the coating. .

This method has been used for a long time because it is relatively easy to form a uniform layer of phosphor, but the drying and firing processes consume a large amount of heat energy, so the recent rise in energy costs has made this method a big issue. It has become a problem.

In order to solve this problem, various studies have been conducted on methods of applying phosphors using so-called electrostatic powder coating methods, in which powder particles are charged and applied directly to a grounded object. has been done. This electrostatic powder coating is a coating method that does not use solvents, so it has become rapidly popular in recent years from the viewpoint of saving resources and being non-polluting. When trying to apply phosphor powder to the inner surface of shaped glass, the most important problem is the uniformity of the application. In other words, a powder injection nozzle for powder coating generally has a structure that injects charged powder particles along with an air stream from its tip, but the nozzle is inserted into a long and thin bulb like the one mentioned above to inject fluorescent powder. When spraying, because the distance between the nozzle tip and the inner surface of the valve, which is the object to be coated, is short, intense air turbulence occurs near the nozzle tip, which prevents uniform application of the powder.

The present invention has been made to solve the above problems, and is provided in a nozzle device of a powder coating device for a fluorescent lamp, in which powder particles are charged by a charging device and applied to the inner surface of a bulb of a fluorescent lamp. In front of the tip of the nozzle body, a powder diffusion element made of a metal mesh having the same polarity as the charging device is disposed at a position corresponding to the opening at the tip of the nozzle body. The purpose is to be able to form a uniform powder layer on the surface as well.

An embodiment of the present invention will be explained below with reference to the drawings. In the drawing, 1 is a cylindrical nozzle body made of a highly insulating material, through which powder particles pass along with the air flow. be. Reference numeral 2 denotes a charging device that charges the powder particles injected from the tip of the nozzle body 1, and includes a charging needle 2a buried in the tip of the nozzle body 1 and protruding toward the center;
A first conductive wire 3 buried in the nozzle body 1
and a high voltage generator (not shown). 4 is a support rod disposed on the central axis of the nozzle body 1 with one end supported by a spider 5 provided inside the nozzle body 1 and the other end protruding from the tip of the nozzle body 1; A conical powder diffusion element made of a metal mesh is fixed to the other end of the support rod 4 at its apex, and a second conduction line 7 embedded in the support rod 4 and the spider 6 connects the first conduction line. 3 and is at the same potential as the charging needle 2. In the fluorescent lamp powder coating device using electrostatic powder coating configured as described above,
To form a phosphor layer on the inner surface of a fluorescent lamp bulb 8, first insert the nozzle body 1 into the grounded fluorescent lamp bulb 8, and apply fluorescent light from a powder supply device (not shown). When the fluorescent powder is transferred into the nozzle body 1 along with the air flow as shown by arrow A in FIG. 2, the fluorescent powder particles are charged by the charged needle 2 and ejected from the tip of the nozzle body 1. At this time, the powder diffusing element 6 installed in front of the tip of the nozzle body 1 is at the same potential as the charging needle 2, that is, the same potential as the charged phosphor powder particles, so the phosphor powder particles and the diffusing element are at the same potential. 6, the injected phosphor powder traces a trajectory in the radial direction of the bulb 8, as shown by the broken arrow B in FIG. 2, and electrostatically hits the tube wall of the bulb 8. Paint. On the other hand, the air flow carrying the phosphor powder particles goes straight from the tip of the nozzle body 1 and reaches the diffusion element 6, but since the diffusion element 6 is made of a wire mesh, most of the air flows as indicated by the solid line arrow in FIG. It passes forward as shown by C. Therefore, air does not violently collide with the pipe wall of the valve 8. In this way, while spraying the phosphor powder particles with the air flow from the tip of the nozzle body 1,
By moving the nozzle body 1 in the direction of the tube axis of the bulb 7 tube, a uniform layer of phosphor can be easily applied to the bulb 7 tube.
It can be formed on the inner surface.

In the above embodiments, a phosphor was described as a powder particle, but other powder particles such as silica can also produce similar effects. In addition, the charging device 2
Although a charging needle is used in this example, other methods may also be used, and although the charging device 2 and the diffusion element 6 are shown to be at the same potential, the present invention is not limited to the above embodiment.
In short, the same effect can be achieved if the charging device 2 and the diffusion element 6 are structured to have potentials of the same polarity.

As described above, the present invention provides a nozzle device for a powder coating device for a fluorescent lamp that electrostatically applies powder particles such as phosphor or Milica to the inner surface of a bulb of a fluorescent lamp. A diffusion element made of a metal net having the same polarity potential as the charging device that charges the powder particles is placed in front of the tip of the nozzle body, which passes along with the air flow, at a position corresponding to the tip opening. The flow of powder particles and air injected from the opening at the tip of the nozzle body can be divided by a diffusion element, such as a bulb for a fluorescent lamp where there is insufficient distance between the tip of the nozzle body and the surface to be coated. Even when powder is applied to the inner surface of a long and thin tube, the applied surface will not be roughened due to air turbulence, and a uniform powder layer can be easily formed on the inner surface of the valve. .

[Brief explanation of the drawing]

1 and 2 are sectional views of essential parts showing one embodiment of the present invention. In the figure, 1 is a nozzle body, 2 is a charging device,
6 is a powder diffusion element.

Claims (1)

[Claims] 1. A nozzle body through which powder particles pass together with an air flow; a charging device provided in the nozzle body to charge the powder particles passing through the nozzle body;
A fluorescent lamp provided with a powder diffusion element disposed in front of the tip of the nozzle body at a position corresponding to the tip opening thereof, and made of a metal net that spreads out and has the same polarity as the charging device. Nozzle device for powder coating equipment. 2. The nozzle device for a powder coating device for a fluorescent lamp according to claim 1, wherein the powder diffusion element has a conical shape, and the apex thereof is located on the side of the opening at the tip of the nozzle. 3. A nozzle device for a powder coating device for a fluorescent lamp according to claim 1 or 2, characterized in that the charging device and the powder diffusion element are electrically connected.