JPH0471655A - Device for preventing sticking of powder of electrostatic painting device - Google Patents

Abstract

PURPOSE:To prevent the sticking of powder to the inside of a container housing the powder and the lumping of the powder by accumulation, deposition, etc., by blowing compressed air into the above-mentioned container through a tube and changing the ejecting direction of air by the oscillation at the floating end of the tube to allow the powder in the container to soar up, thereby preventing the sticking of the powder. CONSTITUTION:A flexible tube 20 consists of a rubber hose or the like and is inserted to the powder expelling container 6 by airtightly penetrating, for example, a fixing table 5. The point where the tube 20 penetrates the fixing table 5 is fixed to the fixing table 5 and the insertion end is made as the floating end 20a. The outside end of the tube 20 is connected to a supply source for the compressed air, such as air pump 21. The compressed air is injected through the tube 20 into the powder expelling container 6 when the compressed air is sent into the tube from the pump 21. Since the insertion end of the tube 20 is the floating end 20a, this floating end 20a is oscillated by a change in the pressure of the compressed air, etc. The ejecting direction of the air is changed by this oscillation to allow the powder in all directions in the container 6 to soar up uniformly. The sticking of the powder to a specific place is prevented in this way.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to an apparatus for electrostatically coating powder on the inner surface of a tube, etc. The present invention relates to a powder adhesion prevention device that prevents powder from adhering and forming agglomerates due to accumulation, deposition, etc.

(Prior Art) For example, an incandescent light bulb has a light diffusing film formed by adhering powder such as silicon dioxide to the inner surface of the bulb, and is known as a diffusion type light bulb.

When forming a light diffusing film on the inner surface of the bulb, a method of electrostatic coating of silicon dioxide powder is employed, as known from Japanese Utility Model Publication No. 40053/1983.

The conventional electrostatic coating device will be further explained based on FIG. 2.

In the figure, reference numeral 1 denotes a turning table which rotates intermittently. A large number of heads 2 (the figure shows one head) are provided around the swivel table 1 at intervals in the circumferential direction.
A glass bulb 3 of an incandescent light bulb is placed over these heads 2 with the opening facing downward. head 2
An insertion hole 4 is provided in the center thereof to penetrate therethrough.

5 is a fixed table, and a powder removal container 6 is installed at a predetermined position on this fixed table 5.

A powder introduction opening 7 is formed on the top surface of the second powder removal container 6, and a powder removal port 8 is also provided on the side wall. A suction tube 9 is connected to this powder discharge port 8 .

Further, a powder injection nozzle 10 is inserted through the powder removal container 6 so as to be able to move up and down.

As shown in the above-mentioned publication, this powder injection nozzle 10 has a hollow vibrator shape with an open end, and silicon dioxide powder stored in a supply tank (not shown) is passed through the inside of the vibrator. It is designed to be injected along with compressed air. This nozzle 10 also serves as an electrostatic discharge electrode, and is connected to the cathode of an electrostatic generator (not shown).

In such an electrostatic coating apparatus, when the glass bulb 3 is placed on the head 2 of the rotating table 1 that rotates intermittently and the powder is sent to the electrostatic coating position shown in the figure, the powder injection nozzle 10 (not shown) The tip of the nozzle 10 protrudes from the powder introduction opening 7 on the top surface of the powder removal container 6, passes through the insertion hole 4 formed in the center of the head 2, and passes through the center of the valve 3. will be entered.

In this state, the electrostatic generator is operated to generate electrostatic force between the powder injection nozzle 10 and the valve 3, and the nozzle 1
Silicon dioxide powder is injected together with compressed air through 0. Then, the powder injected into the valve 3 is drawn to the inner surface of the valve 3 by electrostatic force, and is adhered to the inner surface of the valve 3 by this electrostatic force.

Electrostatic painting is done by this, but at this time,
The amount of powder injected from the powder injection nozzle 10 is in excess of the amount that is deposited on the inner surface of the valve, and this excess powder is passed through the insertion hole 4 formed in the center of the head 2. The powder is introduced into the powder removal container 6 through the powder introduction opening 7.

The powder in the powder removal container 6 is returned to the supply tank via a suction tube 9 from a powder removal port 8 formed in the side wall.

(Problem to be solved by the invention) In the device as described in 2, the air flow inside the powder removal container 6 is directed from the powder introduction opening 7 on the top surface to the powder removal port 8 formed in the side wall. Therefore, this flow is constant, and air stagnates at the corners of the container 6, causing stagnation.

In areas where the air flow is weak or where it stagnates, powder may accumulate and accumulate, and may adhere to the inner surface of the container 6.
It adheres to the side surface of the powder injection nozzle 10.

If powder adheres to the side surface of the powder injection nozzle 10 when the powder injection nozzle 10 is lowered, when the nozzle 10 rises, the adhered powder is brought into the inside of the valve 3 in the form of a lump, and is coated on the inner surface of the valve. The thickness of the film may become uneven.

The present invention was made to solve the above-mentioned problems, and its purpose is to have a very simple structure, but to prevent powder from accumulating or depositing inside the container. It is an object of the present invention to provide a powder adhesion prevention device for an electrostatic coating device that can prevent such problems.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a flexible tube as a container for storing powder in an apparatus for electrostatically coating powder on an object to be coated, such as the inner surface of a tube. , fixing the inserted proximal end of this tube and making the tip a floating end, connecting the outer end of this tube to a source of compressed air, and blowing compressed air into the container through the tube, In this case, the device is characterized in that the direction of the air jet is changed by swinging the floating end of the tube, and the powder in the container is thrown up to prevent the powder from adhering to the container.

(Function) According to such a configuration, when compressed air is blown into the container through the flexible tube, the inner end of this tube is a floating end, so it swings due to pressure fluctuations, etc.
This rocking changes the direction of air ejection, so that the powder in the container is thrown up instead of five, and it is possible to prevent the powder from adhering to a specific location.

(Example) An example of the present invention applied to an apparatus for electrostatically coating the inner surface of a tube with powder will be described below with reference to FIG.

In this embodiment, parts that are the same as those in the conventional structure shown in FIG. 2 are designated by the same numbers, and explanations thereof will be omitted.

This embodiment differs from the conventional one in that a flexible tube 20 is inserted into the powder removal container 6.

The flexible tube 20 is made of a rubber hose or the like, and is inserted into the powder removal container 6 through, for example, the fixed table 5 in an airtight manner. The insertion proximal end of this tube 20, that is, the part that passes through the fixed table 5, is fixed to the fixed table 5, and the insertion tip is a floating end 20a. The outer end of the tube 20 is connected to a compressed air supply source such as an air pump 21.

In such a configuration, when compressed air is sent from the pump 21, this air is injected into the powder removal container 6 through the tube 20. In this case, since the insertion tip of the tube 20 is a floating end 20a, this floating end 20a swings due to changes in the pressure of compressed air.

Therefore, due to this rocking, the direction of air jetting changes, and powder particles in all directions within the container 6 are thrown up. Therefore, it is possible to prevent the powder from adhering to a specific location within the container 6.

As a result, when the powder injection nozzle 10 is descending, powder is prevented from adhering to the side surface of the powder injection nozzle 10.
Since the powder is prevented from being brought into the valve 3 when it rises, the thickness of the coating film on the inner surface of the valve can be made uniform.

Moreover, with the above configuration, it is sufficient to simply insert the flexible tube 20 that injects compressed air into the powder removal container 6.
The structure is simple and can be realized at low cost.

Note that the present invention is not limited to the above embodiments.

In other words, electrostatic coating is not only applied to the application of silicon dioxide to create a light-diffusing film on the inner surface of a bulb, but also, for example, to the application of phosphor powder for a phosphor coating. It is possible to implement even if there is.

Furthermore, the present invention is not limited to electrostatic coating on the inner surface of a tube, and in short, any object may be coated.

Furthermore, in electrostatic coating equipment, powder may adhere or
It is not only the powder removal container 6 that is problematic due to accumulation and accumulation.
A similar problem may occur in powder supply tanks, etc., and this may impede the fluidity and dispersibility of the powder, so it is possible to carry out the process even in such tanks, and in short, it is possible to carry out the process even in such tanks, where the powder is stored. Can be applied to containers.

[Effects of the Invention] As explained above, according to the present invention, when compressed air is blown into the container through the flexible tube, the floating end inside the tube swings and the direction of the air jet is changed. It is possible to blow up all the powder in the container without any particles, thereby preventing the powder from adhering to a specific location. Moreover, this structure has the advantage that it is simple and can be realized at low cost since it is sufficient to insert a flexible tube for injecting compressed air into the container.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electrostatic coating device for the inner surface of a tube showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional electrostatic coating device. 1. Turning table, 2. Head, 3. Valve, 5.
Fixed table, 6. Powder removal container, 1o. Powder injection nozzle, 20. Flexible tube, 20a floating end, 21. Air pump. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A flexible tube is inserted into a container containing powder in an apparatus for electrostatically coating powder on objects to be coated, the proximal end of this tube is fixed, the tip is a floating end, and the outer end of this tube is fixed. Connect the section to an air supply source, blow compressed air into the container through the tube, and in this case, by swinging the floating end of the tube, the direction of the air jet is changed and the powder in the container is thrown up. A powder adhesion prevention device for an electrostatic coating device, characterized in that powder adhesion is prevented by