Feeder

Abstract

The feeder 3 includes: a ceiling part 10; side wall parts 6a, 6b supporting the ceiling part 10; and electric heating elements 11a, 11b supported by the ceiling part 10 and heating a molten glass Gm. The side wall parts 6a, 6b have an inner surface 6c and protrusions 7a, 7b protruding from the inner surface 6c. The protrusions 7a, 7b have a support surface 7c for supporting the ceiling part 10.

Description

Feeder

[0001] The present invention relates to a feeder capable of flowing molten glass.

[0002] For example, when supplying molten glass to a bushing for forming glass fiber, a forming body for forming sheet glass, or the like, it is necessary to keep the molten glass flowing inside the feeder warm and prevent its temperature from decreasing. As a method for achieving this, a method of heating the molten glass by a heating means disposed in the internal space of the feeder has come to be widely adopted.

[0003] For example, Patent Document 1 discloses a feeder whose peripheral wall is made of refractory material and whose internal space is provided with an electric heating element. The internal space of this feeder includes a bottom, a pair of side walls, and a ceiling covering the upper part of the side walls. The electric heating element is supported by the ceiling and located near the side walls (see Figure 2 of the same document).

[0004] Japanese Patent Application Laid-Open No. 2014-221700

[0005] The interior space of the feeder is kept at a high temperature due to heating by the electric heating element and the heat of the molten glass, which causes creep deformation of the ceiling of the feeder over time.

[0006] The position and posture of the electric heating element supported on the ceiling changes with the deformation of the ceiling, which can cause the electric heating element to come into contact with the side wall of the feeder, potentially damaging the side wall and the electric heating element.

[0007] The present invention has been made in view of the above circumstances, and has as its technical object to suppress creep deformation in the ceiling portion of a feeder.

[0008] (1) The present invention is intended to solve the above-mentioned problems, and is a feeder for circulating molten glass therethrough, comprising a ceiling portion, a side wall portion supporting the ceiling portion, and an electric heating element supported by the ceiling portion and heating the molten glass, wherein the side wall portion has an inner surface and a protruding portion protruding from the inner surface, and the protruding portion has a support surface for supporting the ceiling portion.

[0009] According to this configuration, the ceiling portion is supported by the support surface of the protrusion that protrudes from the inner surface of the side wall portion, thereby making it possible to suppress creep deformation of the ceiling portion.

[0010] (2) In the feeder described in (1) above, the side wall portion may include a first side wall portion and a second side wall portion arranged at a predetermined interval, the ceiling portion may be formed of a long fire-resistant member spanning the first side wall portion and the second side wall portion, and the protrusion may include a first protrusion portion protruding from the inner surface of the first side wall portion and a second protrusion portion protruding from the inner surface of the second side wall portion.

[0011] According to this configuration, the ceiling portion is supported by the support surface of the first protruding portion and the support surface of the second protruding portion, thereby making it possible to more effectively suppress creep deformation of the ceiling portion.

[0012] (3) In the feeder described in (1) or (2) above, the protrusion may include a plurality of protrusions arranged along a flow direction of the molten glass, and the electric heating element may be located between two adjacent protrusions among the plurality of protrusions.

[0013] According to this configuration, the electric heating element can be placed inside the feeder without coming into contact with the protruding portion.

[0014] According to the present invention, creep deformation in the ceiling portion of the feeder can be suppressed.

[0015] It is a longitudinal cross-sectional view showing a glass fiber manufacturing apparatus. It is a cross-sectional view taken along the line II-II in Fig. 1. It is a cross-sectional view taken along the line III-III in Fig. 2. It is a cross-sectional view of the upper part of a feeder. It is a perspective view of a ceiling part.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0017] FIG. 1 is a longitudinal sectional view showing an outline of a glass fiber manufacturing apparatus equipped with a feeder according to the present invention.

[0018] The manufacturing apparatus 1 includes a melting furnace 2 that melts glass raw material Gr to form molten glass Gm, and a feeder 3 that is connected downstream of the melting furnace 2 and allows the molten glass Gm to flow therethrough. Walls that define the melting space of the melting furnace 2 and the flow space of the feeder 3 are made of refractory materials such as bricks.

[0019] An inlet 2a is provided at the upstream end of the melting furnace 2 for introducing glass raw material Gr, which is a mixture of silica sand, limestone, soda ash, cullet, etc., into the furnace. A raw material supply means (not shown), such as a screw feeder, is disposed at the inlet 2a.

[0020] The melting furnace 2 is further provided with a heating device (not shown). As the heating device, for example, a gas burner or an electric heater disposed above the molten glass Gm, or an electric heating device such as an electrode immersed in the molten glass Gm can be used.

[0021] The glass frit Gr introduced from the inlet 2a is melted by heating using a heating device, thereby continuously forming molten glass Gm. The molten glass Gm flows into the feeder 3 from the downstream end of the melting furnace 2. The melting furnace 2 may melt the glass frit Gr only by gas combustion or only by electric heating, or may melt the glass frit Gr by a combination of gas combustion and electric heating.

[0022] A plurality of bushings 4 made of platinum or a platinum alloy are provided at intervals in the longitudinal direction X of the feeder 3, i.e., the flow direction of the molten glass Gm, below the feeder 3. Each bushing 4 is provided with a plurality of bushing nozzles (not shown). Each nozzle causes the molten glass Gm to flow down and form glass fibers Gf. The molten glass Gm flowing down from each nozzle is formed into glass fibers Gf (glass filaments) having a predetermined diameter while being stretched downward. A sizing agent is applied to the glass fibers Gf, and then the plurality of glass fibers Gf are bundled together to form glass strands.

[0023] As shown in FIG. 2, the feeder 3 includes a bottom 5, a pair of side wall portions 6a and 6b fixed to the upper portion of the bottom 5, a ceiling portion 10 supported by the side wall portions 6a and 6b, and electric heating elements 11a and 11b supported by the ceiling portion 10 and serving as a heating device for heating the molten glass Gm.

[0024] The bottom portion 5 , together with parts of the side wall portions 6 a and 6 b , forms a flow path for circulating the molten glass Gm in the longitudinal direction of the feeder 3 .

[0025] The pair of side walls 6a, 6b are arranged at a predetermined interval in the width direction Y of the feeder 3. The side walls 6a, 6b include a first wall 6a located at one end of the feeder 3 in the width direction Y and a second side wall 6b located at the other end of the feeder 3 in the width direction Y.

[0026] 2 and 3, each of the side walls 6a, 6b has an inner surface 6c, an outer surface 6d, and a support surface (upper surface) 6e that supports the ceiling portion 10. The support surface 6e is configured as a flat surface that extends horizontally. In FIG. 3, each of the ceiling portions 10 is indicated by a two-dot chain line.

[0027] The inner surface 6c of each side wall portion 6a, 6b is formed with protrusions 7a, 7b that protrude inward from the inner surface 6c. The protrusions 7a, 7b include a first protrusion 7a that protrudes from the inner surface 6c of the first side wall portion 6a and a second protrusion 7b that protrudes from the inner surface 6c of the second side wall portion 6b.

[0028] 3, each of the protrusions 7a, 7b includes a plurality of protrusions formed on the inner surfaces 6c of the side walls 6a, 6b at intervals D1 along the longitudinal direction X (flow direction of the molten glass Gm) of the feeder 3. This interval D1 is set to, for example, 100 mm or more and 400 mm or less.

[0029] 3, the first protrusion 7a and the second protrusion 7b are arranged symmetrically with respect to the center line CL of the feeder 3. That is, the first protrusion 7a and the second protrusion 7b are arranged to face each other in the width direction Y of the feeder 3. The positions of the first protrusion 7a and the second protrusion 7b are not limited to this embodiment, and the position of the first protrusion 7a in the longitudinal direction X of the feeder 3 may be different from the position of the second protrusion 7b in the longitudinal direction X of the feeder 3.

[0030] The protrusion length L1 of each of the protrusions 7a, 7b in the width direction Y of the feeder 3 is, for example, 50 mm to 200 mm. The protrusion length L1 of the protrusions 7a, 7b is preferably 0.04 to 0.15 times the length L2 of the ceiling portion 10 (0.04L2≦L1≦0.15L2). The width W1 of the protrusions 7a, 7b, i.e., the length W1 of the protrusions 7a, 7b in the longitudinal direction X of the feeder 3, is preferably 0.12 to 4 times the width W2 of the ceiling portion 10 (0.12W2≦W1≦4W2).

[0031] 3, each of the protrusions 7a, 7b includes a plurality of protrusions having different widths W1, but the widths W1 of all the protrusions 7a, 7b may be the same.

[0032] Each of the protrusions 7a, 7b has a support surface 7c that supports the ceiling portion 10. Each support surface 7c is configured as a flat surface along the horizontal direction. Each support surface 7c is located at the same height as the support surface 6e of each of the side wall portions 6a, 6b. In other words, the support surface 7c of each of the protrusions 7a, 7b is continuously connected (flush) with the support surface 6e of each of the side wall portions 6a, 6b.

[0033] As shown in FIGS. 3 and 4, a gas burner 8a and a thermometer 8b are attached to the side walls 6a and 6b.

[0034] The gas burner 8a is used temporarily at the start of production of the glass fiber Gf to heat the inside of the feeder 3. Once the production of the glass fiber Gf becomes stable, the gas burner 8a is stopped and the inside of the feeder 3 is heated only by the electric heating elements 11a and 11b. The thermometer 8b is used periodically to control the temperature inside the feeder 3 and the molten glass Gm.

[0035] The side walls 6a, 6b have a first through hole 9a for inserting the gas burner 8a and a second through hole 9b for inserting the thermometer 8b. Each through hole 9a, 9b is a linear hole that penetrates from the inner surface 6c to the outer surface 6d of each side wall 6a, 6b. As shown in Fig. 4, each through hole 9a, 9b is circular, but is not limited to this shape and may be rectangular or various other shapes.

[0036] 3 and 4, the first through-hole 9a is formed at a position between two adjacent first protruding portions 7a among the plurality of first protruding portions 7a formed along the longitudinal direction X of the feeder 3. Similarly, the second through-hole 9b is formed at a position between adjacent second protruding portions 7b.

[0037] The through holes 9a, 9b are preferably formed at positions separated from the electric heating elements 11a, 11b across the protrusions 7a, 7b so as not to overlap with the positions where the electric heating elements 11a, 11b are provided.

[0038] That is, it is preferable that protrusions 7a, 7b are disposed between the gas burner 8a attached to the first through-hole 9a and the electric heating elements 11a, 11b. By shielding the gas burner 8a from the electric heating elements 11a, 11b with the protrusions 7a, 7b, it is possible to prevent deterioration of the electric heating elements 11a, 11b due to the heat from the gas burner 8a.

[0039] Similarly, protrusions 7a and 7b are preferably disposed between the thermometer 8b and the electric heating elements 11a and 11b. By shielding the thermometer 8b from the electric heating elements 11a and 11b with the protrusions 7a and 7b, the thermometer 8b can measure the temperature inside the feeder 3 without being affected by the electric heating elements 11a and 11b.

[0040] In this embodiment, the first through hole 9a and the second through hole 9b are formed adjacent to each other, but this is not limited to this, and protrusions 7a, 7b may be interposed between the first through hole 9a and the second through hole 9b.

[0041] 3 and 4, the upper portion of the feeder 3 is closed by arranging a plurality of ceiling portions 10. The ceiling portions 10 are formed of elongated fireproof members that span the first side wall portion 6a and the second side wall portion 6b. The ceiling portions 10 are formed in a rectangular parallelepiped or plate shape, but are not limited to these shapes.

[0042] 2 and 3, the length dimension L2 of the ceiling portion 10 is greater than the distance D2 between the inner surfaces 6c of the pair of side walls 6a, 6b. As a result, one longitudinal end of the ceiling portion 10 is supported by the support surface 6e of the first side wall portion 6a and the support surface 7c of the first protrusion 7a. Meanwhile, the other longitudinal end of the ceiling portion 10 is supported by the support surface 6e of the second side wall portion 6b and the support surface 7c of the second protrusion 7b.

[0043] As shown in Figures 2 and 5, some of the ceiling sections 10 have a pair of through holes 13a, 13b through which the electric heating elements 11a, 11b are inserted. Each through hole 13a, 13b penetrates the ceiling section 10 in the vertical direction (thickness direction). Each through hole 13a, 13b is configured in a circular shape, but is not limited to this shape and may be configured in a rectangular shape or other shapes. The through holes 13a, 13b include a first through hole 13a formed on one end side of the ceiling section 10 and a second through hole 13b formed on the other end side of the ceiling section 10.

[0044] The electric heating elements 11a and 11b are made of, for example, molybdenum disilicide (MoSi ２2, the electric heating elements 11a and 11b are U-shaped members each having a bent portion 11c and two straight portions 11d arranged in parallel with each other via the bent portion 11c.

[0045] 2 and 4 , the electric heating elements 11a and 11b are supported on the ceiling portion 10 via fixing members 12. The electric heating elements 11a and 11b include a first electric heating element 11a supported on one end of the ceiling portion 10 and a second electric heating element 11b supported on the other end of the ceiling portion 10. The first electric heating element 11a is inserted into a first through-hole 13a in the ceiling portion 10, and the second electric heating element 11b is inserted into a second through-hole 13b in the ceiling portion 10.

[0046] 4, the first electric heating element 11a is located between two adjacent first protrusions 7a in the longitudinal direction X of the feeder 3, among the multiple first protrusions 7a on the first side wall 6a. Although not shown, the second electric heating element 11b is located between two adjacent second protrusions 7b in the longitudinal direction X of the feeder 3.

[0047] As shown in Fig. 2, the fixing member 12 is placed on top of the ceiling portion 10. The fixing member 12 supports parts of the electric heating elements 11a and 11b outside the feeder 3. The fixing member 12 has protrusions 12a that are inserted into the through holes 13a and 13b in the ceiling portion 10. The protrusions 12a function as guides for positioning the fixing member 12 relative to the through holes 13a and 13b in the ceiling portion 10.

[0048] To fix the electric heating elements 11a, 11b to the ceiling portion 10, the electric heating elements 11a, 11b inserted into the through holes 13a, 13b of the ceiling portion 10 are attached to the fixing member 12, and then the protrusions 12a of the fixing member 12 are inserted into the through holes 13a, 13b of the ceiling portion 10. This positions the fixing member 12 in the through holes 13a, 13b of the ceiling portion 10, and fixes the electric heating elements 11a, 11b to the ceiling portion 10. The fixing member 12 also airtightly closes the through holes 13a, 13b of the ceiling portion 10.

[0049] Hereinafter, a method for producing glass fiber Gf using the above-configured production apparatus 1 will be described. This method includes a melting step, a supplying step, and a molding step.

[0050] In the melting step, glass raw material Gr is melted in a melting furnace 2 to form molten glass Gm. In the supplying step, the molten glass Gm is caused to flow inside a feeder 3 and is supplied to a bushing 4 provided below the feeder 3. In the forming step, the molten glass Gm is caused to flow down from a bushing nozzle provided in the bushing 4 to form glass fibers Gf.

[0051] According to the feeder 3 according to the present embodiment described above, the ceiling portion 10 can be supported by the support surfaces 6e of the side walls 6a and 6b as well as the support surfaces 7c of the protrusions 7a and 7b. Therefore, compared to a case where the ceiling portion 10 is supported only by the side walls 6a and 6b, a wider area of ​​the ceiling portion 10 can be supported by the support surfaces 7c of the protrusions 7a and 7b. This makes it possible to effectively suppress creep deformation of the ceiling portion 10.

[0052] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0053] In the above embodiment, the feeder 3 used to manufacture glass fiber Gf is illustrated, but the present invention is not limited to this configuration. The present invention can also be applied to the manufacture of various glass products, such as glass plates and glass tubes.

[0054] 3 Feeder 6a First side wall portion 6b Second side wall portion 6c Inner surface of side wall portion 7a First protrusion portion 7b Second protrusion portion 7c Support surface of protrusion portion 8a First electric heating element 8b Second electric heating element 10 Ceiling portion Gm Molten glass X Flow direction of molten glass

Claims

1. A feeder for circulating molten glass therethrough, comprising: a ceiling portion; a side wall portion supporting said ceiling portion; and an electric heating element supported by said ceiling portion and heating said molten glass, wherein said side wall portion has an inner surface and a protruding portion protruding from said inner surface, and said protruding portion has a support surface for supporting said ceiling portion.

2. A feeder as described in claim 1, wherein the side wall portion includes a first side wall portion and a second side wall portion arranged at a predetermined interval, the ceiling portion is formed of a long fire-resistant member spanning the first side wall portion and the second side wall portion, and the protrusion portion includes a first protrusion portion protruding from the inner surface of the first side wall portion and a second protrusion portion protruding from the inner surface of the second side wall portion.

3. A feeder as described in claim 1 or 2, wherein the protrusions include a plurality of protrusions arranged along the flow direction of the molten glass, and the electric heating element is located between two adjacent protrusions of the plurality of protrusions.

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