JP2570913B2 - Glass melting crucible - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass melting crucible used for continuous spinning of glass fibers.

[0002]

2. Description of the Related Art In order to spin glass fibers, it is necessary to melt raw materials at a high temperature and homogenize them by completely eliminating bubbles, decomposed substances, and the like contained in the molten glass. If the molten glass containing air bubbles is spun as it is, air bubbles are mixed in the glass fiber, and the spinning cannot be performed stably or the strength of the fiber decreases. In addition, when the molten glass containing the decomposed product is spun, the glass fiber is colored and the fiber strength is reduced.

In order to remove such bubbles in the molten glass, in the case of a relatively small-sized glass fiber spinning apparatus,
A glass material is charged into a batch-type melting crucible, and sufficient time is taken for melting and refining the material, and then the molten glass is supplied to a bushing for spinning.

[0004]

However, in such a batch method that requires a long time for melting and fining, if a large amount of raw material is supplied to perform the spinning for a long time, the liquid depth of the molten glass becomes large. Therefore, even if bubbles are generated inside the molten glass near the bottom of the molten crucible, it does not easily rise to the liquid level and it is difficult to remove the bubbles. Excess glass decomposition products are not removed from the glass. The quality of glass fiber obtained from such molten glass is low.

An object of the present invention is to provide a glass melting crucible capable of continuously and efficiently removing bubbles and decomposition products from a large amount of molten glass.

[0006]

SUMMARY OF THE INVENTION The present invention provides a melting chamber for melting glass raw materials, a fining chamber having a plane area sufficient to clarify the molten glass supplied from the melting chamber, and a method for refining glass from the melting chamber to the fining chamber. An object of the present invention is to provide a glass melting crucible provided with a flow rate adjusting valve for adjusting the flow rate of molten glass.

[0007]

[Action] The interior of a batch type crucible is divided into a large-capacity melting chamber and a large-area, small-volume refining chamber, and the glass is first melted in a batch mode in the melting chamber. The refining chamber is moved at a shallow liquid depth to remove bubbles and decomposed products and supply clear glass to the bushing.

[0008]

Next, the present invention will be described more specifically based on examples. FIG. 1 is a sectional view showing a specific example of a molten crucible according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. The melting crucible 10 of the present invention has a melting chamber 1 for melting a glass material in a single crucible, and a fining chamber 2 for fining the glass material supplied from the melting chamber. The partition wall 3 provided between the melting chamber 1 and the refining chamber 2 is provided with a vertical wall 3a provided vertically from the upper part of the crucible to almost near the bottom of the crucible, and a height from the bottom of the crucible to the lower end of the vertical wall 3a. A vertical wall 3b, and a lower end of the vertical wall 3a and a vertical wall 3b;
And a horizontal wall 3c connecting the upper ends of the horizontal lines. A raw material supply port 4 for supplying a glass raw material is provided at an upper part of the melting chamber 1 partitioned by the partition walls 3, and a bushing outlet 5 to a bushing (not shown) is provided at a lower part of the fining chamber 2. An outflow control valve 6 for opening and closing the valve is provided. The horizontal wall 3c is provided with an outlet 7 for supplying the molten glass 11 from the melting chamber 1 to the refining chamber 2 and a flow control valve 8 for adjusting the flow rate. The position of the horizontal wall 3c depends on the raw material and viscosity of the molten glass or the plane area of the fining chamber and the holding time.

As described above, the content of the melting chamber 1 is
Is much larger than the internal volume of the glass raw material, and is easily vitrified by a batch of glass raw materials. Further, the fining chamber 2 has a significantly larger plane area (bottom area) than its internal volume. For this reason, the volume of the molten glass 12 held in the fining chamber 2 is small, but the surface area is large, and the molten glass 12 in the fining chamber 2 maintains a long moving time (residence time) while forming a sufficiently thin liquid depth. You. The ratio between the area and the volume of the glass liquid surface of the refining chamber 2 (glass surface area ^(cm 2) / Glass volume ^(cm 3)) is a so ^{1 cm -1} on more than the removal of bubbles and decomposition products is facilitated Is preferred.

Next, the melting of glass using the glass melting crucible of FIG. 1 will be described. In FIG. 1, a powdery glass raw material supplied from a raw material charging port 4 is melted and vitrified in a melting chamber 1. The capacity of the melting chamber 1 is much larger than that of the fining chamber 2, and a sufficient melting time is secured.
The molten glass 11 that has been melt vitrified is supplied downward from the outlet 7 to the fining chamber 2 by raising the flow control valve 8. In the fining chamber 2, the liquid surface area of the molten glass is extremely large compared to the liquid depth, and the molten glass 12 stays for a long moving time (residence time) while forming a sufficiently thin liquid depth. The liquid depth of the molten glass 12 in the refining chamber 2 is almost 1 by opening and closing the flow control valve.
It is set to 0 mm or less, and defoaming and decomposition product removal are performed efficiently. The thus-obtained clear molten glass 12
Is discharged from the bushing outlet 5 while adjusting the liquid level of the bushing by operating the outflow amount adjusting valve 6.

The crucible may be a crucible having a structure in which the partition between the melting chamber and the refining chamber in the crucible is not provided with a vertical portion but only a horizontal portion, and the entire lower portion of the melting chamber is a refining chamber.

As the material of the molten crucible of the present invention, molybdenum, tungsten, tantalum, niobium, etc. are used. When manufacturing a molten crucible using a difficult-to-weld material such as molybdenum, it is necessary to fold the end of the workpiece to be bent almost at a right angle and weld the surfaces of the bent margin to prevent weld cracking of the material. preferable. By performing such welding, even if local expansion of the molybdenum material occurs due to heating at the time of welding, the bent portion serves as a buffer portion to prevent cracking of the material.

[0013]

According to the present invention, a large amount of glass can be continuously melted by a relatively small capacity melting crucible, followed by removing bubbles and decomposed products in a short time to clarify the molten glass.
High quality glass fiber is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a specific example of a molten crucible of the present invention.

FIG. 2 is a sectional view taken along line AA of the molten crucible of FIG.

[Explanation of symbols]

 1 Melting chamber 2 Refining chamber 8 Flow control valve

Claims (1)

(57) [Claims] 1. A melting chamber for melting a glass material, a fining chamber having a plane area sufficient to clarify the molten glass supplied from the melting chamber, and a flow rate of the molten glass from the melting chamber to the fining chamber. It has a flow control valve, and the ratio (glass surface area (cm ² ) / glass volume (cm ³ )) of the liquid surface area and the glass volume that can be held in the fining chamber is 1 cm ⁻¹ or more. There is a glass melting crucible.