JPS61211934A - Manufacture of circular fluorescent lamp - Google Patents

Abstract

PURPOSE:To aim at preventing a straight tube from of bulb from deforming at the time of its softening due to reinforcing action exhibited by its low temperature part while being softened, thus making the following ring forming work more accurate and easier, by thermally softening, a straight pipe from of bulb held horizontally so as to give such a temperature pattern as to make alternately a high and low temperature part. CONSTITUTION:A straight pipe form of bulb 1 at a heating position P3 is heated in such a way that a comparatively high temperature part and low one are placed in line alternately at the desired length in the direction of bulb axis. For example, the bulb 1 being placed on between a pair of horizontal carrier rollers 11-11, is axle driven by rotation of said rollers, while a number of burners a1-an are arranged in parallel in the direction of bulb axis near the straight bulb 1, changing the output to be supplied to each burner, provided that the number of burners should be determined so as to enable the nth burner an for heating the other end of the bulb 1 to yield bigger output.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for manufacturing an annular fluorescent lamp, and more particularly to a heating method for bending a straight tube bulb into an annular shape.

L! There are two methods for manufacturing straight tube or annular fluorescent lamps: the vertical method, in which the straight tube bulb is supported vertically, and the horizontal method, in which the straight tube bulb is supported horizontally. be.

Ordinary straight tube fluorescent lamps are manufactured using a vertical method, but in recent years, with the aim of high-speed mass production and high quality fluorescent lamps, the manufacturing of straight tube fluorescent lamps has been completed by eliminating almost all of the work processes. It tends to be done in a horizontal manner. This horizontal type straight tube fluorescent lamp is manufactured through the following process steps. In other words, the sealing process involves holding a straight tube bulb whose inner surface has been previously treated (coating and baking a fluorescent film, etc.) horizontally and welding a stem with electrodes and an exhaust pipe to the openings at both ends. Inert gas is flowed into the valve from one side of the exhaust pipe extending from the stem at both ends of a straight pipe type valve, and the inside of the valve is exhausted from the other side to clean the inside of the valve. Seal both exhaust pipes by supplying the desired inert gas such as argon and mercury. (
It is manufactured through a process such as an exhaust process (tip-off), a process of fixing a cap to both ends of a straight pipe valve, and an aging process.

In such a horizontal manufacturing method, since the straight pipe valve is held horizontally, the valve receiver between each work process is simplified and the number of connections is increased. In addition, the clean exhaust inside the straight tube type bulb can be achieved by flowing gas from one side of the exhaust pipe at both ends to the other, making it possible to perform the exhaust work at high speed, resulting in high-quality fluorescent lamps. has.

On the other hand, the manufacturing of annular fluorescent lamps involves the process of heating and softening the stem-sealed straight tube bulb and bending it into an annular shape. Most of the work processes are carried out vertically as follows. That is, hold the straight pipe valve with the inner surface treated vertically and seal the stem at the opening at the lower end of the valve, then turn the straight pipe valve upside down and seal the stem at the other open end. The next step is to attach the stem-sealed straight pipe valve to the exhaust head with the exhaust pipe leading out only from its upper end, grip the upper end of the valve with a chuck, and suspend it vertically using its own weight. Fill the inside of the valve with inert gas from the exhaust pipe to about atmospheric pressure and put it into a heating furnace.When the straight pipe valve, which has been heated and softened to the zero temperature, comes out of the heating furnace, the lower end of the valve is inserted into a two-part type. It is manufactured by gripping a part of the outer periphery of a bending drum, rotating and raising the bending drum, and bending a straight pipe valve into an annular shape.

, <° ゝIt is theoretically possible to perform the heating and bending process of the annular fluorescent lamp in a horizontal manner, and various attempts have been made. However, if a straight pipe valve is held horizontally and heated to soften it, the center of the horizontal straight pipe valve will sag and curve due to its own weight, or the cross-sectional shape of the valve will change from a perfect circle to a horizontally long oval shape. This deformation makes it extremely difficult to bend the bulb using the next bending drum, and it also deteriorates the appearance of the bulb that has been bent into an annular shape. Currently, we are using a vertical method.

However, vertical manufacturing is inferior to horizontal manufacturing in terms of high-speed mass production. In particular, it was difficult to speed up the process of vertically suspending, heating, and bending straight pipe valves, and this process made it difficult to achieve high-speed mass production of all work processes. In addition, as a way to increase the index of the heating and bending process for straight pipe valves using the vertical method, two straight pipe valves are hung as a set and simultaneously heated and softened to be bent into an annular shape. However, the current situation is that they are not sufficiently effective in achieving high-speed mass production.

The present invention is a horizontal type annular fluorescent lamp ffJ 3
This was done in view of the above-mentioned problems in the heating and bending process of straight pipe valves that make it difficult to put them into practical use. The straight pipe valve is heated and softened to a temperature pattern in which a plurality of high temperature parts and low temperature parts are arranged alternately in the axial direction, and then the straight pipe valve is bent into an annular shape.

1. When a straight pipe valve held horizontally is heated and softened in a temperature pattern that alternately becomes a high temperature part and a low temperature part as in the above method, the low temperature part strengthens the straight pipe valve as it softens. This function prevents deformation of the straight tube bulb when it softens, makes the subsequent bending process accurate and easy, and facilitates the practical application of the horizontal method of manufacturing annular fluorescent lamps.

The method of the present invention will be explained below based on a simple embodiment shown in the drawings.

First, an example of an annular fluorescent lamp manufacturing line employing the present invention will be explained with reference to FIG. When a predetermined sealing position 9572 is reached, two stems (4) (4) having an electrode (2) and an exhaust pipe (3) are simultaneously welded to the openings at both ends of the straight pipe valve (1). Immediately after this welding, gripping recesses (5) (5) necessary for the valve bending process are formed on the outer periphery of both ends of the straight pipe valve (1). Next, while holding the straight pipe type valve (1) horizontally, send it to the exhaust position P3 and exhaust the air from the exhaust pipe (3) to clean the inside of the valve.The straight pipe type valve is also filled with nitrogen, and the internal electrode Prevents post wire oxidation.

Next, while holding the straight pipe valve (1) horizontally, place it in the heating furnace (
7), where it is heated and softened by the method of the present invention described later. Immediately after the heated and sufficiently softened straight pipe valve (1) leaves the heating furnace (7), at the bending position P4, the concave portion (5) at one end of the straight pipe valve (1) is Grip the two drums (8a) (811) of the split-type curved drum (8) with claws (9) (9) protruding from the lower end of the outer periphery, and press both drums (8a) (
8b) are combined coaxially. In addition, this curved drum (8)
Prior to gripping the valve end, the exhaust pipe (3) on the side to be gripped by the curved drum (8) is canted off, and the other end of the straight pipe valve (1) that is not gripped by the curved drum (8) is canted off. The concave part (5) of is gripped with the chuck (10).

Then, the bending drum (8) is rotated along the straight pipe valve (1) to bend the straight pipe valve (1) into an annular shape, and the processed annular valve (1°) is After cooling, the curved drum (8) is separated into two drums (8a) (8b) and separated from the annular valve (1°). After this, both stems ( 4) Electricity is applied through the leads (6) (6) extending from (4) to electrodes (2) (
At the same time as the activation of step 2), necessary post-treatments such as evacuation and injection of inert gas and mercury are performed.

By the way, the straight pipe valve (
The heating in step 1) is performed in such a way that high-temperature sections with relatively high temperatures and low-temperature sections with relatively low temperatures are arranged alternately over a desired length in the direction of the valve axis.For example, as shown in Figs. 2 and 3, The straight pipe valve (1) is placed between a pair of horizontal transport rollers (11) (11) (11), and the straight pipe valve (1) is rotated by the rotation of the transport rollers (11) (11). let On the other hand, near this straight pipe valve (1), there are a number of burners (a, (ax), -
・-(an) and each burner (al), (ax
), -...(an) 0 For example, the circumference of the first burner (al) that heats one end of the straight pipe valve (1) is increased, and the circumference of the next second burner is increased. The circumferential size of the burner (a2) is made smaller and the circumferential size of the third burner (a3) is made larger. However, for straight pipe valves (1
) The number of burners is determined so that the circumference of the n-th burner (a n) that heats the other end of the burner is large. A burner like this (
When the straight pipe valve (1) is heated simultaneously with a, x), (a2), -... (an), the large burner (al) on the circumference
, (a3), --- The heated part in (a n) is the high-temperature part (the shaded area in the drawing) Hl % Hl s ---
Hn, and other burners (a2), (a4), -...(
The part heated by an-1) becomes a low temperature part C2, C4, -=Cn-1, which is slightly lower in temperature than the high temperature part.

The straight pipe type valve (1) is heated by injecting an inert gas such as nitrogen gas into the valve at about atmospheric pressure. In addition, high-temperature parts H1 are arranged alternately in the axial direction of the straight pipe valve (1).
, Ha, ... and the temperature and width of the low temperature part CtSC4, ... are determined by the material of the straight pipe valve (1), the pipe outer diameter, the pipe length, etc. For example, the pipe length is 565s+s, the pipe outer diameter is 301I11 30 wand annular fluorescent lamp pulp,
In a straight pipe valve (1) made of soda glass with a softening point of, for example, 695'H, there are high temperature parts H,, H,...
・-・with a width of approximately 110a+m and a temperature of approximately 720℃, the low temperature part C
2, C4, -. is heated to about 695° C. over a width of approximately 110 ssI. In addition, the heating temperature of the high temperature section is limited to about 735°C, and the low temperature section must be set above the softening point temperature.
It is desirable that the temperature difference between them is about 10℃ or more.
Further, the heating width can be changed as appropriate within the range of about 50 to 200 cm. When heated in this way, the straight pipe valve (1) is softened to the extent that it can be bent as a whole, and the low temperature section C
1s C4,'-- is the high temperature part H1, Hl,...
By reinforcing the valve, deformation of the valve due to its own weight is extremely reduced, and subsequent annular bending processing can be performed easily and accurately.

In addition, the bending process of the straight pipe valve (1) is performed using a bending drum (8).
This is done by gripping one end of the straight pipe valve (1) and rotating it to the other end.At this time, the straight pipe valve (1) has both ends formed by curved drums (8). It is stretched more strongly. Therefore, it is desirable that the above-mentioned heating of the straight tube type valve (1) be set at high temperature areas H1s and Hn so that both ends of the valve can be easily extended during bending.

The heating means of the straight pipe valve (1) at the heating position Pa is not limited to the burners (al), (C2), -.
For example, the apparatus shown in FIG. 4 or 5 may be used. In FIG. 4, a large number of burners (bl), (bt
) , ・== (b n) are arranged along the straight pipe valve (1) by alternating the distance from the straight pipe valve (1) to the straight pipe valve (1). Nearby burner (b
1), (ba), etc. are heated to a higher temperature, and the parts facing the more distant burners (bg), (b4), etc. are heated to a lower temperature. Also, Figure 5 shows a large number of burners (dl), (d2), ... (drn) with the same circumference.
is placed parallel to the straight pipe valve (1), and the straight pipe valve (
1) and the burners (C1), (Ct), ..., arrange heat shield plates (12) (12) near the part of the straight pipe valve (1) that you want to heat at a relatively low temperature. In this case, the straight pipe valve (1) has a heat shield plate (12) (1
2) Place the heat shield plate (12
) (12) The part peeking through between... is heated to a higher temperature.

Furthermore, as a means for conveying the straight tube valve (1) from the heating position pa to the bending position P4, a large number of conveyance rollers (13) as shown in FIG. 6 may be arranged in parallel, for example. This conveyance roller (13) has convex portions (14) (14) on the outer periphery corresponding to the low temperature portions C2, C4, --., high temperature portions 111, H of the straight pipe valve (1).
3. The outer periphery corresponding to '-・ is a concave part (15) (15)
With rollers that are ..., only the low temperature parts C2, C4, ..., which are relatively hard to deform, of the straight pipe valve (1) contact the convex parts (14) (14) - of the conveying roller (13). Since the straight pipe valve (1) is transported while being held in place, it is more effective in preventing deformation of the straight pipe valve (1).

In the present invention, soda glass or so-called low-lead glass having a lead content of about 5% can also be used for the straight tube type bulb.

As described above, according to the present invention, even if a straight tube type bulb is fed horizontally to be heated and softened, the bulb deformation due to its own weight is reduced, so that the horizontal method for manufacturing annular fluorescent lamps can be put to practical use. Therefore, high-speed mass production of annular fluorescent lamps becomes possible.

[Brief explanation of the drawing]

The drawings are for explaining the present invention in detail, and FIG. 1 is a schematic perspective view of the valve in each work process, and FIGS. 2 and 3 are side views of the valve heating means in the valve heating position shown in FIG. 1. Figures 4 and 5 are side views of other valve heating means in the valve heating position of Figure 1, and Figure 6 is a modification of the valve holding means in the valve heating position of Figure 1. It is a side view which shows an example. (1)... Straight pipe valve, (4)... Stem, Hl
, H3% ・-=Hn ・"High temperature part, C2, C4, ・-
Cn-1...low temperature part.

Claims (1)

[Claims] (1) Prior to bending a horizontally held straight pipe valve into an annular shape, a temperature pattern is created in which a plurality of high-temperature parts and low-temperature parts are arranged alternately in the axial direction of the straight pipe valve. A method for manufacturing an annular fluorescent lamp characterized by softening it by heating.