Bushing for producing glass fibers

Abstract

A bushing for producing glass fibers, including: a base plate; and multiple nozzles from which molten glass is discharged, in which a nozzle group formed with the alignment of the multiple nozzles is joined to the base plate. A coating layer made of ceramics is formed on each of the nozzles forming at least a row of the outermost layer of the nozzle group, but the coating layer does not cover the entire nozzle, that is, the nozzle is covered so as to be in a state of no coating layer in the vicinity of the nozzle tip.

Claims

1. A bushing for producing glass fibers, comprising: a base plate; and a plurality of nozzles from which molten glass is discharged, wherein a nozzle group formed with alignment of the plurality of nozzles is joined to the base plate, a coating layer made of ceramics is formed on each of the plurality of nozzles forming at least a row of an outermost layer of the nozzle group, each of the plurality of nozzles on which the coating layer is formed has an end face with no coating layer and a nozzle tip part with no coating layer on a side of glass discharge, and each of the plurality of nozzles on which the coating layer is formed has a length of the coating layer that is 50% or more and 90% or less with respect to an entire length of the nozzle, wherein the base plate and each of the plurality of nozzles are made of platinum or a platinum alloy.

2. The bushing for producing glass fibers according to claim 1, wherein a coating layer made of ceramics is formed further on at least a part of the base plate.

3. The bushing for producing glass fibers according to claim 2, wherein a thickness of the coating layer is 50 μm or more and 500 μm or less.

4. A method for producing the bushing for producing glass fibers defined in claim 2, comprising the step of putting a cap on each of the plurality of nozzles on which a coating layer is to be formed to cover each nozzle end face and each nozzle tip part, and then applying coating.

5. A method for producing the bushing for producing glass fibers defined in claim 2, comprising the step of pressing a filling material in from an inlet port of molten glass of each of the plurality of nozzles on which a coating layer is to be formed, protruding the filling material from a discharge port of each of the plurality of nozzles on which a coating layer is to be formed, deforming the protruded filling material so that the filling material covers each nozzle end face and each nozzle tip part, and then applying coating.

6. The bushing for producing glass fibers according to claim 1, wherein a thickness of the coating layer is 50 μm or more and 500 μm or less.

7. A method for producing the bushing for producing glass fibers defined in claim 6, comprising the step of putting a cap on each of the plurality of nozzles on which a coating layer is to be formed to cover each nozzle end face and each nozzle tip part, and then applying coating.

8. A method for producing the bushing for producing glass fibers defined in claim 6, comprising the step of pressing a filling material in from an inlet port of molten glass of each of the plurality of nozzles on which a coating layer is to be formed, protruding the filling material from a discharge port of each of the plurality of nozzles on which a coating layer is to be formed, deforming the protruded filling material so that the filling material covers each nozzle end face and each nozzle tip part, and then applying coating.

9. A method for producing the bushing for producing glass fibers defined in claim 1, comprising the step of putting a cap on each of the plurality of nozzles on which a coating layer is to be formed to cover each nozzle end face and each nozzle tip part, and then applying coating.

10. The method for producing the bushing for producing glass fibers according to claim 9, wherein a part or all of a base plate, and nozzles except for the plurality of nozzles forming at least a row of an outermost layer of the nozzle group are masked, and then coating is applied.

11. A method for producing the bushing for producing glass fibers defined in claim 1, comprising the step of pressing a filling material in from an inlet port of molten glass of each of the plurality of nozzles on which a coating layer is to be formed, protruding the filling material from a discharge port of each of the plurality of nozzles on which a coating layer is to be formed, deforming the protruded filling material so that the filling material covers each nozzle end face and each nozzle tip part, and then applying coating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates one embodiment of the bushing plate for producing glass fibers according to the present invention (only the nozzle row of the outermost layer is coated).

(2) FIG. 2 illustrates one embodiment of the bushing plate for producing glass fibers according to the present invention (all of the nozzles are coated).

(3) FIG. 3 illustrates one embodiment of the bushing plate for producing glass fibers according to the present invention (the base plate and all of the nozzles are coated).

(4) FIG. 4 illustrates the bushing plate for producing glass fibers of the present embodiment.

(5) FIG. 5 illustrates a method (silicon cap) for treating a nozzle tip when a coating layer is formed in the present embodiment.

(6) FIG. 6 illustrates another method for treating a nozzle tip when a coating layer is formed.

DESCRIPTION OF EMBODIMENTS

(7) Hereinafter, the embodiment of the present invention will be described. FIG. 4 illustrates a bushing plate 100 for producing glass fibers produced in the present embodiment. In FIG. 4, a bushing plate for producing glass fibers is provided with a base plate 10, and multiple nozzles 20 aligned on the bottom face.

(8) The base plate 10 is formed of a plate material made of platinum (bottom face size: 444 mm×120 mm, having a thickness of 1.5 mm). Further, the nozzles 20 are joined to the base plate 10 with the formation of four nozzle groups in island shapes. In each of the nozzle groups, 20 nozzles×20 nozzles are joined at 6.4 mm intervals. The total number of the nozzles joined to the base plate 10 is 1600. Each of the nozzles 20 has a tapered cylindrical body having an outer shape of 2.94 mm (outer diameter at the upper end)×2.35 mm (outer diameter at the lower end). Further, the entire length of the nozzle after the joining to the base plate is 4 mm. In addition, the base plate and the nozzles are all made of platinum.

(9) In the bushing plate 100 for producing glass fibers of the present embodiment, a coating layer of yttria-stabilized zirconia is formed on all of the nozzles 20 and the base plate 10. The coating layer is not formed in an area within 0.8 mm in the vertical direction from the nozzle tip on an end face of the nozzle, and the base metal is exposed in the area. That is, the coating layer is formed in an area having a length of 80% with respect to the entire length of the nozzle. In addition, The thickness of the coating layer is 300 μm or less.

(10) As the production process of the bushing plate for producing glass fibers of the present embodiment, the nozzles 20 processed to the above dimensions by boring were aligned and joined to the base plate 10. In the joining of the nozzles 20, holes are made in the nozzles in advance and the nozzles 20 are inserted at respective nozzle attaching positions of the base plate 10, respectively, and then heating was performed to preliminary join the nozzles 20 to the positions in an electric furnace, and further, the base of the joint part was welded from an upper face of the base plate (inflow face of molten glass) with a YAG laser beam. In this way, a bushing plate before coating is produced.

(11) Prior to the formation of the coating layer, a cap made of silicon was put on a tip of each nozzle (FIG. 5). After that, a coating layer was formed on the entire surface of the bushing plate by a thermal spraying method. After the coating layer is formed, the silicon cap was removed to obtain the bushing plate for producing glass fibers of the present embodiment.

(12) In this regard, as the method for forming the coating layer partially on the nozzle, the silicon cap was put on the nozzle tip in the present embodiment. In addition to such a technique, there is also a method in which a filling material including clay, modified silicon, a resin or the like is pressed in from a back side (inflow face of molten glass) of a base plate, the filling material is extruded from a discharge port of the nozzle so as to be protruded, and the protruded filling material was crushed and deformed so as to cover the nozzle tip part, and then a coating layer is formed to cover the part other than the tip part of the nozzle (FIG. 6).

(13) Further, in the present embodiment, a nozzle was masked with a silicon cap, and then a coating layer was formed on the entire surface. As described above, the coating may be performed partially. In this case, a part or all of the base plate and nozzles except for nozzles of the outermost layer of a nozzle group are masked, and then the coating is performed, and as a result of which a coating layer can be formed in a desired area.

(14) In addition, as a production example of glass fibers by the use of the bushing plate for producing glass fibers of the present embodiment, first, a terminal and a box-shaped side flange are joined to the above-described bushing plate to form a bushing that is a box-shaped container, the bushing was assembled in a device for producing glass. The device for producing glass is provided with a melting tank for a glass raw material prepared to be a desired composition, a refining tank for molten glass, and a stirring tank for stirring and homogenizing the clarified molten glass, and the bushing is arranged on the downstream side of those tanks. The glass fibers discharged from the bushing are appropriately wound up.

(15) Herein, production of glass fibers was performed for one year by a device for producing glass provided with the bushing plate for producing glass fibers of the present embodiment. During this period, remarkable abnormality was not visually observed in the bushing plate, and the spinning of glass fibers was stable. Further, after one-year operation of the device, the device was shut down and the nozzles of the bushing plate were inspected. As a result, platinum particles were not observed on the base plate. In addition, although slight abrasion of around 0.1 to 0.2 mg/mm.sup.2 was observed in the coating layer of the nozzles, any thickness reduction of the platinum basis material of the nozzles was not observed.

INDUSTRIAL APPLICABILITY

(16) The present inventive bushing plate for producing glass fibers enables stable operation of a device for producing glass over a long operation period, and thereby efficient production of good quality glass fibers.