JPS59209245A - Manufacture of flare for tube bulb - Google Patents

Abstract

PURPOSE:To reduce generation of a crack in the manufacturing process while stably increasing mechanical strength of a stem by directly spraying sulfurous acid gas on the internal surface of the flare part through a reamer member when manufacturing a stem flare. CONSTITUTION:One body of a reamer proper 14 and a processing plate is rotated for inserting the processing plate 15 into the glass tube tip 6 while simultaneously spraying SO2 gas 12 from the tip of the reamer proper 14, for instance, in the rate of about 1l/min. Then SO2 gas 12 come out from the reamer proper 14 flows toward the internal surface of the flare part 13 from the parallel side of the processing plate 15 while further going round the flare part external surface from the tip of the flare part 3 for flowing out to the glass tube 6 along the outside of the flare part 3. The flow of SO2 gas 12 like this is performed nearly stably with no influence of the turbulent flow of the surrounding air due to the relative rotation of the reamer 13 and the flare 3 and as a result an Na2SO4 buffer layer is surely formed on the in-and-outside surfaces of the flare part 3 and its periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a method for manufacturing flares for fluorescent lamps, cathode ray tubes, etc., and particularly to a method for imparting impact resistance.

In the prior art, for example in a fluorescent lamp, the open end of the glass pulp is sealed with a stem (1) as shown in FIG. This stem (1) has two lead wires (2) (2),
It consists of a crushed sealing part of the lead wire (2) (2) and a flare part (1) (3) extending from the crushing sealing part, and the outer peripheral end of the flare part (3) is connected to a glass bulb (4). It is sealed at the open end of the Note that (5) is a filament coil connected to the lead wires (2) (2).

The stem (1) is generally made of lead glass, and its manufacture is usually carried out in the steps shown in FIGS. 2 to 5. First, the second
As shown in the figure, attach the glass tube (6) to the head (7) with its tip (6゛) protruding.
°) with a burner flame (8) to soften it. Next, a reamer member (9) whose outer peripheral surface is partially conical is inserted into the softened glass tube tip (6°) while rotating coaxially, and the glass tube is shaped as shown in Fig. 3. Tip (6”
) is expanded into a conical shape to form a flared portion (3). After the flared portion is formed, the heating is stopped, the reamer member (9) is removed, and the glass tube (6) is cut from the broken line in FIG. 4 to obtain a flare (1°). After that, as shown in Figure 5, connect the flare (1) to the lead wire (2) (2) and the exhaust pipe (not shown).
is inserted, the cylindrical portion (2) of the flare (1°) is heated and softened, and then crushed with pinchers (10) to seal the lead wire to obtain a stem (1).

By the way, this stem (1) had a disadvantage in that when it was sealed to the glass bulb (4), the flare part became microscopic due to mechanical cracks during the manufacturing process of the stem.

For example, flares (1゛) are cut out one by one using a Syntron feeder, etc., and fed to the stem machine, but during this transportation, mechanical shocks such as vibrations are applied, resulting in fine particles and ranks, especially in the flare part (3). Something happened. There is no problem with this crank if it remains fine, but cracks caused by the heat generated when the stem (1) is sealed to the bulb (4) can develop into large cracks, causing the fluorescent lamp to be defective. Also, in the process of sealing the stem (1) to the valve (4), when the stem (1) is placed on the mount pin, the mechanical shock from the mount pin to the flare part causes minute cracks in the flare part. As mentioned above, this may develop into a large rank due to the heat during sealing, resulting in the entire bulb being defective (3).

As a solution to the above problem, sodium sulfite (Na) is added by spraying sulfur dioxide gas onto the surface of the flare part during flare manufacturing.
2304) to form a buffer layer.

This buffer layer has the effect of protecting the stem (1) from external shocks, and has been recognized to have the effect of suppressing the occurrence of cracks. However, the stem manufacturing method including the formation of this buffer layer has the following problems.

C1 Problems to be Solved by the Invention The buffer layer (Na2504) is formed by inserting a reamer member (9) into the tip (6') of the glass tube to form a flared part (3) as shown in Figure 6. In this step, sulfur dioxide gas (S02) (12) is sprayed toward the flare part (3) from a nozzle (11) placed on the side of the flare part (3). The spraying of this SO2 gas (12) is approximately 14
S is applied to the flared part (3) which has been softened by heating.
When O2 gas (12) comes in contact with sodium, it reacts with Na.
A thin layer of 2504 is formed, which becomes the buffer (4) layer mentioned above.

However, when the 302 gas (12) is sprayed, a flare (
Since the air flow near the flare part (3) is in a turbulent state due to the rotation of the beam member (9), the 502 gas (,12) blown in the direction of the flare part (3) is affected by the turbulence near the flare. It becomes difficult to touch the surface of the flare part (3) as it is carried away by the flowing air, and the formation state of the fflfi layer becomes unstable, making it impossible to obtain a sufficient buffering effect. For example, flare diameter 301111%
A stem for a 20W fluorescent lamp with a flare wall thickness of 0.9 mm was manufactured using the above method, and the stem was dropped from a height of 20 cm onto an iron plate to examine the crank occurrence rate.
It was found that the buffering effect of Na2504 was insufficient, as crank generation products occurred at a rate of 1.5%.

20 Means for Solving Problems The purpose of the present invention is to form a buffer layer of Na2S04 on the surface of the flared portion so as to exhibit a sufficient buffering effect. Feature (5) is that the 502 gas is directly blown onto the inner surface of the flare portion through the member. In this way, the 502 gas will flow from the inner surface of the flare part to the outer surface of the flare part due to the relative surface transfer between the reamer member and the flare, and a buffer layer of Na2504 will be reliably formed on the inner and outer surfaces of the flare part. target strength increases.

E, Example The present invention modifies the manufacturing method as follows.

For example, a reamer member (13) as shown in FIG. 7 is prepared, and using this reamer member (13), a glass supported by a conventional head (7) as shown in FIGS. 8 and 9 is prepared. The tip (6゛) of the tube (6), heated and softened by the burner flame (8), is expanded to form a flared portion (3). Reamer member (1
3) is a rotatable cylindrical reamer main body (14), a trapezoidal processing plate (15) vertically fixed in the diametrical direction with a gap at the tip of the reamer main body (14), and an outer circumference of the reamer main body (14). Gas supply outer cylinder (16
) and a gas supply pipe (17) that feeds SO2 gas (12) into the outer cylinder (16). A plurality of through holes (18) are formed in part (6) of the outer periphery of the reamer body (14) surrounded by the outer cylinder (16), and gas is supplied from the gas supply pipe (17) into the outer cylinder (16). The S02 gas (12) enters the reamer body (14) through the through hole (18) and flows out through the gap between it and the processed plate (15) at the tip.

Flare production using the above reamer (13) is shown in Figures 8 and 9.
As shown in the figure, rotate the integrated reamer body (14) and processing plate (15) to move the processing plate (15) to the tip of the glass tube (
At the same time, 502 gas (12) is blown from the tip of the reamer body (14) at a rate of about 11/min, for example. Then, the S02 gas (12) coming out of the reamer body (14) flows from the parallel side of the processed plate (15) to the flared part (1).
3), then wraps around from the tip of the flared portion (3) to the outer surface of the flared portion, and flows out into the glass tube (6) along the outer surface of the flared portion (3). 50 like this
2 Gas (12) flows through beam (13) and flare (3)
), the flare part (3
) and (7) Na2504 loose frT layers are reliably formed on the inner and outer surfaces in the vicinity. Although the theoretical elucidation of this result is difficult and has not been fully elucidated, it has been experimentally confirmed and the effectiveness of the present invention has been demonstrated.

Next, an experimental example of the present invention will be described. The diameter of the flare part is 30m+
*20W made of lead glass with a flared wall thickness of 0.9ms+
When manufacturing flares for fluorescent lamp stems, use SO as described above.
2 gas is sprayed at a rate of 1β/min. This flare 2
When we conducted a drop test to check the crank occurrence rate by dropping the product from a height of 0 cm onto a steel plate, the crank occurrence rate was almost 0.
Met. Further, even when a test was carried out in which the material was conveyed while being vibrated with a Syntron feeder, the crank occurrence rate was almost 0. Furthermore, when we investigated the crank occurrence rate after sealing the glass bulb, the crank occurrence rate was almost 0.

Note that the ripper member for carrying out the present invention is not limited to the one shown in FIG. Even if it is something that opens and closes (8).

Further, the present invention is not limited to use in fluorescent lamps, but can be sufficiently applied to tubes such as cathode ray tubes and incandescent light bulbs.

As described in detail, according to the present invention, N is formed on the inner surface of the flare portion.
Since the buffer layer of a2SO4 can be reliably formed, the mechanical strength of the stem can be stably increased, the occurrence of cranks in the manufacturing process can be significantly reduced, and the yield can be improved.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view of a fluorescent lamp, Figs. 2 to 5 are side views at each manufacturing stage to explain the conventional method of manufacturing the flare for the stem shown in Fig. 1, and Fig. 6 is a separate view. FIG. 7 is a perspective view showing an example of a reamer member according to the present invention, and FIGS. 8 and 9 are a side view for explaining the conventional method of manufacturing a stem flare. FIG. 2 is a side view and a sectional view taken along line A-A during flare manufacturing. (9)

Claims (1)

[Claims] (1) Manufacture of a flare tube characterized by blowing sulfur dioxide gas onto the inner surface of the glass tube through the reamer member when expanding the heated end of the glass tube into a conical shape by inserting a reamer member from the outside. Method.