JPH04206228A - Baking method of applied tube for fluorescent lamp and device therefore - Google Patents

Abstract

PURPOSE:To apply for the baking of an applied tube for thin cylindrical fluorescent lamp which is longer than standard size, in particular, by putting the applied tube for fluorescent lamp laterally, and by baking the glass tube for each length part from one end part to the other end part. CONSTITUTION:A powdered phosphor is put into an organic solvent in which the phosphor is resolved and evaporated at no more than 400 deg.C, and this liquid fluorescent application paint is evenly applied on the inside surface of a straight application tube 1, namely, on an application surface 2. An applied tube 1 is put laterally, and while air is blown into the applied tube 1 from a blowing tube 8, from the end not yet baked, in the direction of a baking starting end in such a way that it is streamed, so as to bake the applied tube from one end to the other end for each length part. Air is blown into the applied tube 1 that is once baked, from the baking starting end to the baking finishing end, in such a way that it is streamed, so as to bake the applied tube 1 from one end to the other end for each length part. The applied tube 1 which is longer than standard size, can thus be appropriately baked, while an applied tube 1 of standard size can also be appropriately baked.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for firing coating tubes for fluorescent lamps, which are generally widely used. The present invention relates to a method and apparatus for firing coated tubes for fluorescent lamps, which are useful for firing tubes.

(Prior Art) Currently, linear fluorescent lamps are widely used mainly as home and industrial lighting equipment.

Fluorescent lamps are made by coating the inner surface of a hollow glass tube with phosphor.
The phosphor is caused to emit light by the discharge inside the hollow glass tube,
It is used as a light source for lighting, etc.

Phosphors (for example, calcium halophosphate) are generally refined into powder, and it is not possible to directly and uniformly fix this powdered phosphor onto the inner surface of a hollow glass tube. Generally speaking, this powdered phosphor is mixed with a viscous organic solvent (e.g. nitrocellulose) to make a liquid fluorescent paint, and this fluorescent paint is uniformly spread on the inner surface of a hollow glass tube. A coating method is used. The hollow glass tube coated with fluorescent paint is called a coated tube for fluorescent lamps.

However, this organic solvent is unnecessary after application, so
It must be removed in some way after application. Therefore, taking advantage of the property that phosphors do not deteriorate even at high temperatures, but organic solvents burn and evaporate when heated to high temperatures, we heated the coated tubes for fluorescent lamps in a furnace, removed the organic solvents by combustion, and fluoresced. A commonly used method is to fix only the body to the inner surface of a hollow glass tube.

This method is called firing of coated tubes for fluorescent lamps.

Currently, the common method of firing is to heat the entire coated tube for a fluorescent lamp at the same time, and therefore the firing furnace needs to be large enough to cover the entire coated tube.

As mentioned above, fluorescent lamps are very widely used mainly for illumination, and hence are in high demand.

For this reason, fluorescent lamps are now mass-produced with standardized lengths and diameters, and firing furnaces are also made and used in sizes that suit the size of the fluorescent lamps.

On the other hand, when fluorescent lamps are used for special purposes, such as technology that uses them for dimensional inspection of products rather than for lighting,
A lamp that is longer than the width of the product being inspected may be required. However, conventional standardized fluorescent lamps cannot satisfy the above conditions. Therefore, it may be necessary to specially manufacture a linear fluorescent lamp with a long overall length that satisfies the above conditions.

(Problems to be Solved by the Invention) There are several problems in manufacturing a fluorescent lamp that is longer than standard dimensions, and one of the problems is related to the firing furnace. That is, as described above, the conventional method for firing coated tubes for fluorescent lamps is generally to heat the entire coated tube in a dedicated furnace depending on the size of the coated tube.

Therefore, in order to fire a coated tube that is longer than the standard size using the conventional firing method, it is necessary to make the firing furnace large enough to accommodate the length. However, since there is little demand for such long fluorescent lamps, it is undesirable from a cost standpoint to construct a large furnace specifically for them.

Therefore, instead of the conventional firing method of firing the entire coated tube for fluorescent lamps at the same time, a method can be considered in which the coated tube for fluorescent lamps is laid horizontally and the coated tubes are fired section by length from one end to the other. .

According to this firing method, there is no need to increase the size of the furnace even when firing a long linear coated tube for a fluorescent lamp, and the equipment cost can be reduced. However, since the glass tube is heated to high temperatures (350 to 900 degrees Celsius) during firing, there is a risk that the glass tube may bend or warp. To prevent this, the glass tube is fired while rotating around its axis. methods such as these must be taken. Therefore, a means for rotating and holding the glass tube is required as firing equipment, which poses problems such as the firing apparatus becoming complicated.

In view of the above problems, the present invention is suitable for firing linear coated tubes for fluorescent lamps that are longer than conventional standard dimensions, is also applicable to firing coated tubes for fluorescent lamps that have conventional standard dimensions, and can easily: Another object of the present invention is to provide a method and apparatus for firing a coated tube for a fluorescent lamp, which can be realized at low cost.

(Means for Solving the Problems) In order to solve the above problems, the method for firing a coated tube for a fluorescent lamp according to the present invention uses a viscous organic solvent that decomposes and evaporates powdered phosphor at a temperature below 400°C. After uniformly applying this liquid fluorescent paint to the inner surface of a straight hollow glass tube, turn the glass tube horizontally and first blow air into the glass tube at the unfired end. The glass tube is fired for each partial length from one end to the other end while flowing in the direction of the firing start end, and then air is introduced into the fired glass tube and fired from the firing start end this time. This method is characterized in that the glass tube is fired in sections from one end to the other end while being fed in a flowing direction toward the end.

Further, in order to solve the above-mentioned problems, the present invention provides a baking device for a coated tube for a fluorescent lamp, which has a substantially annular shape and has a heating means on its inner surface, and a holding means for horizontally holding the coated tube for a fluorescent lamp. , a blowing means for sending air into the glass tube using, for example, an air pump, and a coating tube for a fluorescent lamp held by the holding means pass through the center of the approximately annular furnace in the axial direction. The present invention is characterized in that it has an annular furnace and a moving means for mutually moving the holding means, and performs the method of firing the coated tube for a fluorescent lamp.

(Operations and Effects) As described above, in the method and apparatus for firing a coated tube for a fluorescent lamp according to the present invention, the coated tube for a fluorescent lamp is placed horizontally,
Since this glass tube is fired section by length from one end to the other, there is no need to heat the entire glass tube at the same time as in conventional firing methods, and the fluorescent lamp is longer than the standard size. It is suitable for firing coated tubes for fluorescent lamps of standard dimensions, and can be easily realized with low-cost equipment. - Also, since the organic solvent used in fluorescent paint decomposes and evaporates at temperatures below 400"C, the firing temperature can be lower than conventional methods. Therefore, the coating tube for fluorescent lamps can be prevented from bending due to heat, unlike when firing at high temperatures. There is no need to rotate and hold it, which simplifies the equipment.

Furthermore, in order to prevent the organic solvent that decomposed and evaporated during firing from attacking the phosphor fixing surface, the firing was divided into two times, and during the first firing, the vapor of the organic solvent was applied to the fired area. Air is sent into the glass tube so that it flows, and during the second firing, air is sent in the opposite direction from the first time so that the organic solvent vapor does not flow into the area where the second firing has been completed. Therefore, even a small amount of organic solvent adhering to the inner surface of the coating tube after the first firing can be completely removed, resulting in various remarkable effects such as the ability to manufacture high-quality fluorescent lamps.

(Example) An example of the method and apparatus for firing a coated tube for a fluorescent lamp according to the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view schematically showing the overall configuration of an embodiment of the firing apparatus for fluorescent lamp coated tubes according to the present invention, FIG. 2 is a view seen from the top, and FIG. II in Figure 2
It is an I-III end view.

First, the configuration of the firing apparatus of this example will be explained. 1st
As shown in FIGS. 3 to 3, the baking device of this embodiment includes a large number of rotating rollers 5 that hold a linear coating tube 1 for fluorescent lamps horizontally, and a substantially annular roller that is attached to the inner surface of the coating tube 1. A furnace 3 having a heating zone 7, a support pedestal 4 that supports the furnace 3 and the rotating roller 5, a blower pipe 8 inserted into one end of the coating tube 1 and feeding air into the coating tube, and one end. A wire 6 is wound around a winding means (not shown), and the other end is attached to the coating tube 1.

The rotating roller 5 is formed to be thinner at the center than at both ends, and can stably hold the coating tube 1. Also, the rotating roller 5
is pivotally supported by a support plate (not shown), and the respective rollers 5 are installed with their axes parallel to each other at predetermined intervals.

The insertion portion between the blower pipe 8 and the application pipe 1 is filled with a filler 9 to prevent air leakage.

Next, a method for firing a coated tube for a fluorescent lamp according to the present invention will be explained based on the operation of the firing apparatus of this embodiment.

FIG. 4A is a cross-sectional schematic diagram showing the configuration at the time of first firing;
and FIG. 4B is a schematic cross-sectional view showing the configuration at the time of second firing.

As shown in Figs. 1 to 3, the application tube l is
Place it horizontally on top of the The inner surface 2 of the application tube 1 is coated with a fluorescent paint made of polyethylene oxide mixed with a fluorescent substance. This polyethylene oxide decomposes and evaporates at about 200°C, that is, below 400°C, so if the firing temperature is set low, the application tube 1 will not bend or warp during firing without rotating the application tube 1. do not have.

The application tube 1 held by the rotating roller 5 is shown in FIG.
As shown in Figure B, it is fired twice. As shown in FIG. 4A, the coating tube 1 is first moved in the direction of arrow A by the wire 6 attached to the right end, and is moved from the right end to the left end by the heating zone of the furnace 3 for each partial length. It is heated and fired for the first time. During this time, air is sent through the blower tube 8 inserted into the left end of the coating tube 1, and the air flows in the direction of arrow B inside the coating tube 1. Therefore, the polyethylene oxide that evaporates during firing flows toward the right end of the coating tube 1 that has been fired for the first time, so the polyethylene oxide vapor flows into the unfired part and corrodes the surface coated with the fluorescent paint. prevent. During this first firing, a portion of the evaporated polyethylene oxide cools down and the inner surface 2
Since it may adhere to the surface, a second firing is performed.

As shown in Figure 4B, the coating tube 1 has been fired for the first time.
is moved in the direction of arrow C by a wire 6 attached to the left end, and the second firing is performed for each partial length from the left end to the right end. During this time, air is sent in from the blower tube 8 inserted into the left end of the coating tube 1, and the air flows in the direction of arrow B inside the coating tube 1, as in the first firing. Therefore, the polyethylene oxide that slightly adhered to the inner surface 2 during the first firing will be removed during the second firing.
Since it does not flow toward the left end after the second firing, it can be completely removed without remaining on the inner surface 2. In this way, high quality firing becomes possible.

The method and apparatus for firing a coated tube for a fluorescent lamp according to the present invention have been described above based on one embodiment, but the present invention is not limited to this embodiment. for example,
In the above embodiment, polyethylene oxide was used as the organic solvent that decomposes and evaporates at 400°C or lower, but other organic solvents that decompose and evaporate at 400°C or lower may be used. Further, in the above embodiment, the coating tube 1 is pulled by the wire 6, but if the rotating roller 5 is provided with a driving means and the coating tube 1 is moved by the rotation of the rotating roller 5,
Wire 6 is not necessary. Further, in the above embodiment, the rotating roller 5 has a shape that is thinner at the center than at the ends, but it may have another shape as long as it can stably hold the application tube.

Further, in the embodiment described above, the furnace 3 was fixed to the support frame 4 and the coating tube 1 was moved, but it is also possible to make the furnace 3 movable. Hereinafter, an embodiment in which the furnace 3 is made movable will be described based on the drawings.

FIG. 5 is a perspective view showing the overall structure of another embodiment of the firing apparatus for a coated tube for a fluorescent lamp according to the present invention.

As shown in FIG. 5, the baking apparatus of this embodiment includes a rotating roller 5 that holds a linear coating tube 1 for a fluorescent lamp horizontally.
and a furnace 3 having a substantially annular shape and having a heating zone on its inner surface;
It consists of a support frame 4 that supports the furnace 3 so as to be movable in the direction of arrow AB, and a blower tube 8 that is inserted into one end of the coating tube 1 and sends air into the coating tube.

The feature of this embodiment is that the furnace 3 is installed movably on the support frame 4, whereas in the previous embodiment, the furnace 3 is installed movably on the support frame 4. In comparison, the device itself can be made smaller and space-saving. The method for firing the coating tube 1 differs in that, while in the previous embodiment, the coating tube 1 was fired while being moved, in this embodiment, the coating tube 1 is fired while the furnace 3 is moving. There is no difference in the firing method for coated tubes for fluorescent lamps.

As explained above, the method and apparatus for firing a coated tube for a fluorescent lamp according to the present invention can be modified in various ways without impairing its effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing the overall configuration of an embodiment of the firing apparatus for fluorescent lamp coated tubes according to the present invention, FIG. 2 is a view seen from the top, and FIG. Tl1-■ in the diagram
II end view, FIG. 4A is a cross-sectional schematic diagram showing the configuration at the first firing, FIG. 4B is a cross-sectional schematic diagram showing the configuration at the second firing, and FIG. 5 is a fluorescent lamp according to the present invention. It is a perspective view which shows the whole structure of another Example of the baking apparatus of the coating tube for lamps. 1... Coating tube for fluorescent lamp 2... Fluorescent paint coating surface 3... Furnace 4... Support frame 5...
・Rotating roller 6... Wire 7... Heating zone 8... Air pipe 9... Filler Fig. 5

Claims (1)

[Claims] 1) After uniformly applying a fluorescent paint made by mixing a powdered phosphor in a viscous organic solvent to the inner surface of a substantially elongated cylindrical hollow glass tube, In a method for firing a fluorescent lamp in which a tube is heated in a furnace, the organic solvent in the fluorescent paint is removed, and only the phosphor is fixed on the inner surface of the hollow glass tube, the organic solvent is heated at 400 ° C. or less. Using an organic solvent that has the property of decomposing and evaporating, the hollow glass tube coated with the fluorescent paint is placed horizontally and air is fed into the glass tube so as to flow from the unfired end to the firing start end. , the glass tube is fired in the furnace from one end to the other end for each partial length, and then the furnace is heated while air is fed into the glass tube so as to flow from the firing start end to the firing end end. A method for firing a coated tube for a fluorescent lamp, characterized in that the glass tube is fired section by length from one end to the other end. 2) a substantially annular furnace having a heating means on its inner surface; a holding means for horizontally holding the hollow glass tube after the fluorescent paint has been applied; a blowing means for blowing air into the glass tube; and the holding means. further comprising a moving means for mutually moving the substantially annular furnace and the holding means so that the glass tube held in the glass tube passes through the center of the substantially annular furnace in the axial direction, 1. A firing apparatus for a coated tube for a fluorescent lamp, characterized in that the method for firing a coated tube for a fluorescent lamp according to item 1 is carried out.