JPS596824B2 - Glass fiber spinning furnace sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for gas sealing the atmosphere in a glass fiber spinning furnace, particularly an optical fiber spinning furnace.

Conventional sealing methods for spinning furnaces include using an O-ring as shown in Figure 1 when the heating method is a high-frequency furnace, or reducing the gap between the glass rod and the upper flange to reduce the amount of gas leakage. method has been adopted.

When using such a method, if the outer diameter of the glass rod is not uniform, the gap between the glass rod and the O-ring or upper flange will vary, resulting in fluctuations in the amount of internal atmospheric gas leaking from this area, resulting in changes in characteristics. There were flaws that made things worse. Furthermore, it may be possible to use a seal (O-ring, packing) that can accommodate some degree of non-uniformity in the outer diameter, but in such a case, the glass rod is restrained by the O-ring, packing, etc. used there. For example, if the glass rod is bent or has a sudden change in diameter, excessive force will be applied to the glass rod, causing damage to the sealing part of the glass rod, cracking of the glass rod, etc. I couldn't expect a high quality product due to manufacturing. In order to eliminate these drawbacks, the present invention provides a bag-like or bellows-like flexible cylinder made of a highly airtight material between the upper flange and the glass rod or the chuck portion of the glass rod. The purpose is to perform good spinning by sealing the furnace atmosphere gas without forming a seal part with the rod itself, that is, by eliminating fluctuations in gas leakage and unreasonable force on the glass rod. It is something to do.

A detailed explanation will be given below with reference to the drawings. FIG. 2 shows an embodiment of a vertical spinning furnace using the high frequency induction heating furnace of the present invention, in which 1 is a glass rod, 1' is a spun optical fiber, 2 is a chuck, 3 is a heating element, and 4 is a spinning furnace. Refractory, 5 is a refractory cylinder 6 is the furnace side outer wall, 7 is a coil, 8 is a fixing washer for the lower part of the outer wall, 9 is the outer wall of the lower part of the furnace, 10 is an O-ring, 11 is the outer wall of the upper part of the furnace, 12 is for fixing the upper and lower outer walls Stay, 13 is atmospheric gas inlet, 14 is gas supply hose, 15 is chuck side flange for bellows mounting, 16 is bellows upper mounting seat, 1
7 is a bellows, 18 is a bellows lower mounting seat, 19 is a stay for fixing a bellows mounting flange, 20 is a bellows mounting flange, and 21 is an O-ring for sealing between the bellows mounting flange and the glass rod.

The left side of FIG. 2 shows the case where the bellows is fixed to the chuck 2 of the furnace upper part 16, and the right side shows the case where the bellows is fixed between the furnace upper part and the glass rod using a bellows mounting flange.

To handle these, first cut off the bellows upper mounting seat 16 from the chuck side flange 15 or the bellows mounting flange 20, and after fixing the glass rod 1 to the chuck 2, pull up the bellows 17 and attach the bellows. It is fixed to the chuck side flange 15 or the bellows mounting flange 20 with bolts or the like, and while atmospheric gas is sent into the furnace from the inlet 13 via the hose 14, the temperature of the heating element 3 is raised to perform spinning. Because of this structure, the glass rod 1 behaves as if it had been in the furnace from the beginning, and the sealing performance does not change even if the glass rod 1 is gradually fed to the center of the furnace. 〇 or more,
As explained, the present invention is a method of sealing the gas by using a bellows or the like to seal the glass rod itself as if it had already entered the furnace when it is fed into a furnace with a certain atmosphere. Whether the furnace is vertical or horizontal, the atmosphere inside the furnace does not change and is effective for spinning.

In addition, the heating method is not limited to high frequency induction heating, but also electric heating, C
It has the advantage of being applicable to a wide range of applications such as O2 laser heating.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional spinning furnace body using high-frequency induction heating, and Fig. 2 is an embodiment of the present invention using high-frequency induction heating.
is a glass rod, 1' is a spun optical fiber, 2 is a chuck, 3 is a heating element, 4 is a refractory, 5 is a refractory cylinder, 6
is the outer wall of the furnace, 7 is the coil, 8 is the outer wall lower fixing washer, 9 is the lower furnace outer wall, 10 is the O-ring, 11 is the upper furnace outer wall, 12
1 is a stay on the upper and lower outer walls, 13 is an atmospheric gas inlet, 14 is a gas supply hose, 15 is a chuck side flange for mounting a bellows, 16 is a bellows upper mounting seat, 17 is a bellows, 1
8 is a bellows lower mounting seat, 19 is a stay for fixing the bellows mounting flange, 20 is a bellows mounting flange, 2
11 indicates a flange for attaching a bellows and an O-ring for sealing between the glass rod.

Claims (1)

[Claims] 1. In a glass fiber spinning furnace, a rod or tube of quartz glass or optical glass is gradually inserted into one end of the furnace, the rod or tube is melted inside the furnace, the fibers are spun, and the spun fibers are pulled out from the other end of the furnace. Alternatively, an airtight bag-like or bellows-like flexible tube is provided at the insertion part of the tube, and one end of the tube is attached to the furnace wall and the other end is attached to the glass rod or a chuck part that supports the glass rod. How to seal a glass fiber spinning furnace.