JPS6379730A - Joining method for glass pipe - Google Patents

Abstract

PURPOSE:To simultaneously blow both protruding parts to pieces and to join glass pipes not less than pieces with high working efficiency by simultaneously heating both end parts of the glass pipe of an intermediate part and increasing the pressure of the inside to form a protruding expanded part having a thin wall and heating both protruding parts again and increasing the pressure of the insides. CONSTITUTION:The predetermined parts to be fused of U-shaped glass pipe 1a, 1b, 1c are simultaneously heated with burners 25a, 25b, 25c, 25d for blowing through. Then air is introduced through exhaust pipes 4a, 4b, 4c and pressurized to form protruding expanded parts 6a, 6b, 6c1, 6c2. At this time, the above- mentioned operations are performed for the U-shaped glass pipe 1c of an intermediate part while dividing the operations into plural times. The protruding expanded parts 6a-6c2 are heated again with the burners 25a-25d and simultaneously the insides of the glass pipes 1a, 1b, 1c are pressurized. Respective expanded parts 6a-6c2 are blown to pieces and protruded blown parts 7a-7c2 are formed. Then the blown parts 7c1, 7c2 of the U-shaped pipe 1c are brought into contact with the blown parts 7a, 7b of the other two glass pipes 1a, 1b and fused with a central burner 40 for fusion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for joining a plurality of glass tubes applied to a bent fluorescent lamp or the like.

(Prior Art) Recently, there has been a trend toward smaller size and higher output in fluorescent lamps. In order to make fluorescent lamps smaller and have higher output, it is advantageous to centrally arrange lamps having long discharge paths within a small space.

For this reason, fluorescent lamps as shown in Figs. tJ7 to 9 have been researched and developed. This fluorescent lamp includes, for example, three U-shaped glass tubes 1a.

1b and 1c are arranged so that they are located on each side of a planar substantially triangular shape, and the respective ends of adjacent U-shaped glass tubes are fused at the side surfaces, respectively. The U-shaped glass tubes 1a, lb, lc collectively form one continuous meandering discharge path. Electrodes 3a are provided at the ends of the glass tubes 1a and lb, which are the ends of this discharge path.

3b is sealed. Moreover, each glass tube 1a.

1b and the IC are provided with exhaust pipes 4a, 4b, and 4c, and a phosphor coating 5 is formed on the inner surface. Incidentally, FIG. 9 is a sectional view showing an expanded state.

When manufacturing such fluorescent lamps, conventionally a method has been adopted in which the lamps are joined one by one. That is, first, the parts of the U-shaped glass tube FF1a at the end and the U-shaped glass tube IC in the middle are heated with a burner to soften them, and the softened parts are injected into the interior through the exhaust pipe of each glass tube. The parts are blown out by the pressure of the air or inert gas, the blown out parts are abutted against each other, and the abutted parts are heated with a burner to fuse them together. Next, the U-shaped glass tube 1b at the other end was fused to the U-shaped glass tube IC at the intermediate section in the same manner as described above.

However, according to the above conventional method, the U-shaped glass tubes are joined one by one, which is time-consuming, and the U-shaped glass tube IC in the middle is connected to the U-shaped glass tube 1 at one end.
Since it is heated twice, once when it is fused to the U-shaped glass tube 1b at the other end, and once when it is fused to the U-shaped glass tube 1b at the other end, there is a problem that distortion and cracks are likely to occur.

Therefore, it is conceivable that the intermediate portion of the U-shaped glass tube IC is simultaneously blown out at both ends of the U-shaped glass tube IC to be fused. If both ends are blown out at the same time, work efficiency will be improved, and since two-stage heating and cooling are not required, distortions and cracks will be less likely to occur in the glass tube.

(Problem to be solved by the invention) By the way, when blowing out both ends of a single glass tube at the same time, both ends are heated at the same time, and at this time blow gas is supplied into the glass tube to increase the gas pressure inside the tube. Therefore, a method is adopted in which the softened parts are blown out by double heating.

However, at this time, if either end is blown out before the other end, the pressure inside the glass tube will be released from this blown out opening, and the remaining blown out areas will not be blown out. Put it away.

The present invention aims to provide a method for joining glass tubes, which makes it possible to improve work efficiency by ensuring that both ends are blown out at the same time when forming blowout points at both ends of the intermediate glass tube. It is something to do.

[Structure of the Invention (Means for Solving the Problems)] In the present invention, in a glass tube in which blow-out points are formed at both ends, by simultaneously heating both ends of the glass tube and increasing the pressure inside the tube. , is characterized in that bulging protrusions are formed at each of these ends, and then these bulging protrusions are simultaneously heated again to increase the pressure inside the pipe, so that these bulging protrusions are simultaneously blown out. .

(Function) According to the method of the present invention, since the bulging protrusions are first formed at both ends, these bulging protrusions become thin and easy to blow out, and the bulging protrusions at both ends become thin. The difference in wall thickness can be kept small. After reaching this state,
Since the bulging protrusions were heated again and the pressure inside the tube was increased to blow out these bulging protrusions, the wall thickness was small at this blow-out stage, and the difference in wall thickness between the two bulging protrusions was small. This makes it possible to blow out both at the same time.

For this reason, the probability of simultaneous blowout is higher than the method of blowing out all at once from the beginning.

(Example) The present invention will be described below based on an example shown in FIGS. 1 to 6.

In this embodiment, the three U-shaped glass tubes 1a to 1a described above are used.
This shows a case where the method is applied to the method of bonding ICs, and these three U-shaped glass tubes 1a to 1c are bonded so that they are positioned on each three sides of a triangle, and each U-shaped glass tube The pipes 1a-1c each have exhaust pipes 4a-4C.

First and second U-shaped glass tubes 1 located at both ends
a and lb are located on two sides of the triangle as shown in FIG. 1, and the U-shaped glass tube I in the middle
C is placed at a position spaced apart in the horizontal direction from the remaining side of the triangle.

And exhaust pipes 4a of these glass tubes 1a, lb, lc,
Hoses (not shown) are connected to 4b and 4c.

Blowout burners 25a, 25b, 25c and 25d
each of the above U-shaped glass tubes 1a, lb.

Place it opposite the part of the IC to be fused. In this state, the blowout burners 25a, 25b, 25c and 25d
ignite the U-shaped glass tube 1a with a gas flame.

The lb and lc portions to be fused are heated simultaneously.

Once each part to be fused is heated and softened, the blow-out burners 25a, 25b, 25c and 25d are moved back or the gas flame is extinguished to stop heating, and the exhaust pipes 4a, 4b, 4 Supply air or inert gas into the glass tubes 1a, lb, and lc through the hose connected to c. Then, the glass tube la.

The pressure inside lb and lc rises, and the softened portion to be fused swells. As a result, bulging protrusions 6a, 6b, 6cl, and 6c2 are formed as shown in FIG.

In this case, pressure is supplied to the third U-shaped glass tube IC in the intermediate portion in a stepwise manner. That is, when a pressure slightly higher than atmospheric pressure is first supplied to the U-shaped glass tube 1c for a short period of time, the portion of the glass tube 1c to be fused will swell slightly in proportion to this supply pressure, and this bulge will cause the glass tube IC to swell. The pressure returns to atmospheric pressure. Next, when a pressure slightly higher than atmospheric pressure is supplied again into the glass tube IC for a short time, the bulge further expands in accordance with the supplied pressure. By performing such bulging a plurality of times, the bulging protrusions 6c1 and 6c2 of a predetermined height are formed.

After this, the blowout burners 25a and 25b are used again.

U-shaped glass tube 1a at 25c and 25d.

The above-mentioned bulging protrusions 5a, 6b, and 6Ct of 1b and 1c.

6c2 and exhaust pipes 4a and 4b at the same time.

Air or inert gas is supplied into the glass tubes 1a, lb, lc through 4c (FIG. 3). Then, the bulging protrusions 6a, 6b, 6c1, 6c2 are blown out as shown in FIG. 4, and the protruding bulging parts 7a, 7b, 7cX,
7c2 is formed.

In this way, each glass tube 1 a+ 1 b+
When the blowout portions 7a, 7b, 7c1 and 7c2 are formed in the planned fusion portion of 1c, the blowout burner 25a is activated.

Retract 25b, 25c and 25d.

Next, the U-shaped glass tube IC is moved forward to the remaining side of the triangle as shown by the arrow in FIG. It is brought into contact with the blowout portions 7a and 7b of the tubes 1a and lb.

In this state, the central fusion burner 40 is entered into the center of the triangle surrounded by the three U-shaped glass tubes 1a, lb, and lc, and the outer fusion burners 41 and 42 are moved into the U-shaped shape of the TSL. Blow-out portions 7a and 7c of the glass tube 1a and the third U-shaped glass tube IC are in contact with each other.
The blowout portion 7b of the first and second U-shaped glass tubes 1b and the third first U-shaped glass tube IC are in contact with each other.
.

7c2 and these fusion burners 40.4
Each blowout section 7a, 7b,
7ct and 7C2 are heated (Fig. 6).

By heating the welding burners 40, 41, 42, the blowout parts 7a and 7c1 and 7b and 7c2 that are in contact with each other are heated and softened, so that they are fused together.

Once the burst parts are fused in this way, the fusion burner 40, 41, 42 is moved back, the hose is removed from the exhaust pipe, and the fused parts 2a, 2b are cooled and solidified before being joined. Remove the glass tube.

According to such a method, the first and second U-shaped glass tubes 1a and 1b located at both ends and the third U-shaped glass tube IC located at the center are separated from each other by blowing. After processing, the third U-shaped glass tube 1
c by moving the first and second U-shaped glass tubes 1a,
Since it will be fused with lb, three U-shaped glass tubes 1a and l
b and lc can be joined simultaneously. Therefore, the joining work can be carried out efficiently.

Moreover, in this case, there are three U-shaped glass tubes 1a.

Since the portions 1b and 1c to be fused are heated and blown out at the same time, the fusion work can be done in a short time.

In particular, in the present invention, the intermediate U-shaped glass tube, that is, the third U-shaped glass tube IC, must be provided with blowout portions 7cl and 7c2 at both ends, respectively. Since 7c2 is simultaneously blasted and broken, multi-stage heating and cooling is not required, and distortion and cracks will not occur in this third U-shaped glass tube IC.

In order to process the above-mentioned blow-out portions 7c1 and 7c2 at the same time, first, the bulging protrusion “C1” is attached to the third U-shaped glass tube IC.
* 6c2 is made in advance and these bulging protrusions 5c1 and 6c2 are blown out, so both of these bulging protrusions 6c1 and 6C2 can be blown out at the same time.

That is, when forming the bulging protrusions 6C1 and 6C2, these portions are blasted with the blowout burners 25b and 25.
When the heating by the burners 25b and 25d is interrupted and gas at a pressure slightly higher than atmospheric pressure is supplied into the glass tube IC, the heated and softened portion is pushed out and expanded by the pressure. Due to this bulge, the internal volume within the glass tube IC increases slightly, and the pressure returns to atmospheric pressure. Next, gas at a pressure slightly higher than atmospheric pressure is supplied into the glass tube IC again to further inflate the slightly bulged portion. By repeating such a plurality of stages of expansion, the heights of these expansion protrusions 6c1 and 6c2 are made equal. In this way, the wall thicknesses of the bulging protrusions 6cl and 6c2 are thinner than other parts, and the wall thicknesses of both the bulging protrusions 6cl and 6c2 are approximately the same.

Therefore, in the next blow-out process, both bulging protrusions 6
c1 and 6c2 are blown out at the same time, thus eliminating problems such as one of them being blown out first and the other not being opened.

A specific example will be described in which the blowout portions 7cl and 7c2 are simultaneously formed in the third U-shaped glass tube IC in the intermediate portion.

The glass tube IC is soda lime glass with a tube diameter of 12 m-1 and a wall thickness of 1.0*m.
5b and 25d for about 3.5 seconds to soften.

Next, 100 mgt haq of air was poured into the glass tube IC by 0.5
Supply only for seconds. After this supply, when the supply of air is stopped for 0.2 seconds, the softened portion swells slightly during this stop, and the softened portion naturally cools. Next, after the above-mentioned stop, air of 100+u+ha9 is again supplied into the glass tube IC for 0.5 seconds. After this, the air supply is stopped for 3 seconds. Then, during this second stop, the bulge expands and protrudes to a predetermined height, and natural cooling progresses.

The above is the forming process of the bulging protrusions 6c1 and 6c2,
After the second supply stop, the bulging protrusions 6cl and 6c2 are heated for about 1.5 seconds by the burners 25b and 25d to soften them. While continuing to heat the glass tube I with burners 25b and 25d.
When 700 to 800 m5/Aq of air is supplied into C,
Both the bulging protrusions 6c1 and 6c2 are blown out within 3 seconds, and the blown out parts 7cl and 7c2 are simultaneously opened.

In the above embodiment, three U-shaped glass tubes IC, l
Although the case of joining b and lc has been described, the number of glass tubes to be joined may be any number as long as it is three or more.

Further, the present invention is not limited to the case where U-shaped glass tubes are joined together, but can be implemented even when three or more straight glass tubes are joined together.

[Effects of the Invention] As explained above, according to the present invention, when blow-breaking both ends of a glass tube, bulging protrusions are made in advance at these blow-breaking locations, and then these bulging protrusions are Since it is heated and softened so that it can be blown out, the above-mentioned bulging protrusion has a thin wall compared to other parts, and the difference in wall thickness between the two bulging protrusions can be kept small. When blowing these out, both of them open almost at the same time. Therefore, work efficiency is improved, and the yield rate is also improved without causing distortion or cracks in the glass tube.

[Brief explanation of the drawing]

1 to 6 are explanatory diagrams showing the joining method of the present invention step by step, FIG. 7 is a perspective view of a bent fluorescent lamp for explaining the background art of the present invention, and FIG. 8 is a plan view thereof. FIG. 9 is an expanded view of the same. 1 a, 1 b, 1 c--U-shaped glass tube, 2
a. 2b... Separation part, 4 a, 4 b r 4 c...
・Exhaust pipe, 6a, 6b, 6c1.6C2-bulging protrusion, 7
a. 7b, 7cl, 7c2--Blowout portion, 25a. 25 b, 25 c, 25 d...burner for blowing out, 40.41.42... burner for fusion. Applicant's agent Patent attorney Takehiko Suzue Figure 6 Figure 7

Claims (2)

[Claims] (1) A joining method in which the ends of three or more glass tubes are heated and ruptured, and the ruptured parts are heat-fused and connected to form one continuous glass tube as a whole, Prior to welding the above-mentioned blowout points to each other, the glass tube in the middle, excluding the ends, is heated at the same time at both ends, and the internal pressure is increased to create bulging protrusions that become thinner at these heated points. A method for joining glass tubes, characterized in that the two bulging protrusions are heated again and the internal pressure is increased to simultaneously blow out both the bulging protrusions. (2) The method for joining glass tubes according to claim (1), wherein the glass tube is a U-shaped glass tube.