Feeder

Abstract

The side wall parts (6a, 6b) of the feeder (3) comprise a first side wall part (6a) and a second side wall part (6b) which are arranged at a specified interval. The top parts (7a, 7b) of the feeder (3) are formed by long-strip-shaped fireproof components which are erected on the first side wall part (6a) and the second side wall part (6b). The top portions (7a, 7b) include a first top portion (7a) and a second top portion (7b) disposed adjacent to each other. A first protruding portion (9) of the first top portion (7a) overlaps a second protruding portion (10) of the second top portion (7b) in the vertical direction.

Description

Technical Field

[0001] This invention relates to a feeder capable of allowing molten glass to flow. Background Technology

[0002] For example, when supplying molten glass to bushings used for forming glass fibers or to forming sheets of glass, it is necessary to keep the molten glass flowing inside the feeder warm to prevent its temperature from dropping. As a method for this purpose, heating the molten glass by means of a heating mechanism arranged within the internal space of the feeder has been widely adopted.

[0003] For example, Patent Document 1 discloses a feeder with its peripheral walls made of refractory material and an electric heating element within its internal space. The feeder's internal space includes a bottom, a pair of side walls, and a top covering the upper portion of the side walls. The electric heating element is supported on the top and located near the side walls (see the document). Figure 2 ).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-221700 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The internal space of the feeder becomes high-temperature due to heating by the electric heating element and the heat from the molten glass. As a result, the top of the feeder undergoes creep deformation over time.

[0009] The electric heating element supported at the top changes position and orientation due to deformation of the top. Therefore, it is possible for the electric heating element to come into contact with the side wall of the feeder, resulting in damage to both the side wall and the electric heating element.

[0010] The present invention was made in view of the above circumstances, and its technical problem is to suppress creep deformation at the top of the feeder.

[0011] Solution for solving the problem

[0012] (1) The present invention is a feeder for solving the above-mentioned problems, which allows molten glass to flow inside. The feeder is characterized in that it has a top and a side wall portion supporting the top. The side wall portion includes a first side wall portion and a second side wall portion arranged at a predetermined interval. The top is composed of a strip-shaped refractory member mounted on the first side wall portion and the second side wall portion. The top includes a first top and a second top arranged adjacent to each other. The first top has a first protrusion and the second top has a second protrusion. The first protrusion and the second protrusion overlap in the vertical direction.

[0013] According to this structure, by overlapping the first protrusion of the first top with the second protrusion of the second top in the vertical direction, the first top and the second top can be integrated. This increases the moment of inertia of the integrated top section, thereby suppressing creep deformation of both the first and second tops.

[0014] (2) In the feeder described in (1) above, the first protrusion may have a first contact surface opposite to the second protrusion in the vertical direction, and the second protrusion may have a second contact surface that contacts the first contact surface in a manner that overlaps with the first contact surface in the vertical direction.

[0015] According to this structure, by making the first contact surface of the first protrusion of the first top contact with the second contact surface of the second protrusion of the second top, the creep deformation of the first top and the second top can be effectively suppressed.

[0016] (3) In the feeder described in (1) or (2) above, the feeder may also have an electric heating element supported on the top and used to heat the molten glass.

[0017] According to this structure, damage to the electric heating element can be prevented by suppressing creep deformation at the top.

[0018] (4) In the feeder described in (3) above, the top may have a through hole for the electric heating element to be inserted.

[0019] According to this structure, the electric heating element can be easily installed on the top using the through hole formed on the top.

[0020] (5) In the feeder described in (4) above, the feeder may also include a fixing member for fixing the electric heating element inserted through the through hole to the top.

[0021] According to this structure, the electric heating element can be reliably fixed to the top.

[0022] Invention Effects

[0023] According to the present invention, creep deformation at the top of the feeder can be suppressed. Attached Figure Description

[0024] Figure 1 This is a longitudinal sectional view showing a glass fiber manufacturing apparatus.

[0025] Figure 2 yes Figure 1 A cross-sectional view of the line of sight from direction II-II.

[0026] Figure 3 It is the first top-level 3D view.

[0027] Figure 4 It is a three-dimensional view of the second top.

[0028] Figure 5 This is a cross-sectional view of the top.

[0029] Figure 6 This is a cross-sectional view showing other examples at the top.

[0030] Figure 7 This is a cross-sectional view showing other examples at the top.

[0031] Figure 8 This is a cross-sectional view showing other examples at the top.

[0032] Figure 9 This is a cross-sectional view illustrating the previous method of creep deformation at the top. Detailed Implementation

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0034] Figure 1 This is a longitudinal sectional view showing an outline of a glass fiber manufacturing apparatus equipped with the feeder of the present invention.

[0035] The manufacturing apparatus 1 includes: a melting furnace 2, which melts glass raw material Gr to form molten glass Gm; and a feeder 3, which is connected to the downstream side of the melting furnace 2 and allows the molten glass Gm to flow inside. The walls dividing the melting space of the melting furnace 2 and the flow space of the feeder 3 are formed of refractory materials such as bricks.

[0036] An inlet 2a is provided at the upstream end of the melting furnace 2 for feeding the glass raw material Gr, which is a mixture of silica sand, limestone, soda ash, and crushed glass, into the furnace. A raw material supply mechanism, such as a screw feeder, is provided at the inlet 2a (figure omitted).

[0037] A heating device (not shown) is also provided in the melting furnace 2. For example, an electric heating device such as a gas burner disposed above the molten glass Gm, an electric heater, or electrodes immersed in the molten glass Gm can be used.

[0038] The glass raw material Gr, fed from the inlet 2a, is melted by heating provided by 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. It should be noted that the melting furnace 2 may use only gas combustion or only electric heating to melt the glass raw material Gr, or it may use both gas combustion and electric heating simultaneously.

[0039] Multiple sleeves 4, made of platinum or platinum alloy, are spaced apart at intervals along the length X of the feeder 3, i.e., the flow direction of the molten glass Gm. Each sleeve 4 has multiple nozzles (not shown). These nozzles allow the molten glass Gm to flow down and form glass fibers Gf. It should be noted that the molten glass Gm flowing down from each nozzle is formed into glass fibers Gf (glass monofilaments) of a specified diameter as it extends downwards. After being coated with a binding agent, multiple glass fibers Gf are bundled together to form a glass bundle.

[0040] like Figure 2 As shown, the feeder 3 includes: a bottom 5; a pair of sidewalls 6a and 6b fixed to the upper part of the bottom 5; a top 7 supported on the sidewalls 6a and 6b; and electric heating elements 8a and 8b, which serve as heating devices supported on the top 7 and heating the molten glass Gm.

[0041] The bottom 5, together with a portion of the sidewalls 6a and 6b, forms a flow path that allows the molten glass Gm to flow along the length direction X of the feeder 3.

[0042] A pair of sidewall portions 6a and 6b are arranged at a predetermined interval in the width direction Y of the feeder 3. The sidewall portions 6a and 6b include: a first wall portion located at one end of the feeder 3 in the width direction Y; and a second sidewall portion 6b located at the other end of the feeder 3 in the width direction Y. Each sidewall portion 6a and 6b has a support surface 6c that supports the top 7.

[0043] like Figures 2 to 4 As shown, the top 7 is composed of a long strip-shaped fire-resistant member mounted on the first side wall portion 6a and the second side wall portion 6b. Each top 7 is plate-shaped, but is not limited to this shape. The length dimension L of the top 7 is larger than the distance D between the inner surfaces of the pair of side wall portions 6a and 6b. Thus, one end of the top 7 in the longitudinal direction is supported by the support surface 6c of the first side wall portion 6a, and the other end of the top 7 in the longitudinal direction is supported by the support surface 6c of the second side wall portion 6b.

[0044] like Figure 5 As shown, the upper part of the feeder 3 is blocked by arranging a plurality of tops 7 in a manner. Hereinafter, one of the two adjacent tops 7a, 7b among the plurality of tops 7 will be referred to as the first top 7a, and the other of the two adjacent tops 7a, 7b among the plurality of tops 7 will be referred to as the second top 7b.

[0045] like Figures 3 to 5 As shown, each of the tops 7a and 7b has a protrusion (hereinafter referred to as "width direction protrusion") 9 and 10 protruding along its width direction W and a protrusion (hereinafter referred to as "vertical direction protrusion") 11 and 12 protruding along the vertical direction. It should be noted that the width direction W of the tops 7a and 7b is the same as the length direction X of the feeder 3.

[0046] Hereinafter, the width-direction protrusion 9 of the first top 7a will be referred to as the "first width-direction protrusion", and the width-direction protrusion 10 of the second top 7b will be referred to as the "second width-direction protrusion". In addition, the vertical-direction protrusion 11 of the first top 7a will be referred to as the "first vertical-direction protrusion", and the vertical-direction protrusion 12 of the second top 7b will be referred to as the "second vertical-direction protrusion".

[0047] like Figure 5 As shown, the first top 7a and the second top 7b are arranged side by side with their vertical orientations opposite. That is, the first top 7a is configured such that the first vertical protrusion 11 is located on the upper side and the first width protrusion 9 is located on the lower side. Conversely, the second top 7b is configured such that the second width protrusion 10 is located on the upper side and the second vertical protrusion 12 is located on the lower side.

[0048] The first width-direction protrusion 9 is arranged to overlap the second width-direction protrusion 10 in the vertical direction. Specifically, the first width-direction protrusion 9 of the first top 7a is arranged adjacent to the second vertical-direction protrusion 12 of the second top 7b. The first vertical-direction protrusion 11 of the first top 7a is arranged adjacent to the second width-direction protrusion 10 of the second top 7b.

[0049] The first width-direction protrusion 9 includes a pair of protrusions that project toward one side and the other side of the width direction W of the first top 7a. Similarly, the second width-direction protrusion 10 includes a pair of protrusions that project toward one side and the other side of the width direction W of the second top 7b.

[0050] The first width-direction protrusion 9 has a contact surface (hereinafter referred to as the "first contact surface") 9a ​​that faces the second width-direction protrusion 10 in the vertical direction. The second width-direction protrusion 10 has a contact surface (hereinafter referred to as the "second contact surface") 10a that contacts the first contact surface 9a in a manner that overlaps with the first contact surface 9a in the vertical direction. Each contact surface 9a, 10a is configured as a flat surface along a horizontal direction orthogonal to the vertical direction.

[0051] like Figure 5 As shown, the first width-direction protrusion 9 and the second width-direction protrusion 10 have side surfaces 9b and 10b facing their width direction W. The side surface 9b of the first width-direction protrusion 9 is arranged opposite to a portion of the second vertical-direction protrusion 12 in the second top 7b. On the other hand, the side surface 10b of the second width-direction protrusion 10 is arranged opposite to a portion of the first vertical-direction protrusion 11 in the first top 7a.

[0052] like Figures 3 to 5 As shown, each of the tops 7a and 7b has a top surface 11a, 12a and side surfaces 11b, 12b in the vertical direction. The side surface 11b of the first vertical protrusion 11 is arranged to contact the side surface 10b of the second width protrusion 10. The side surface 12b of the second vertical protrusion 12 is arranged to contact the side surface 9b of the first width protrusion 9.

[0053] Not limited to the structure described above, in a portion of the plurality of first tops 7a and second tops 7b arranged side by side, the side surfaces 11b, 12b of each vertically protruding portion 11, 12 can also be separately arranged from the side surfaces 9b, 10b of the corresponding width-direction protruding portions 9, 10. This creates a gap between the separately arranged side surfaces (see reference). Figure 5 ).

[0054] According to the above structure, the gap can absorb the expansion of the first top 7a and the second top 7b when they expand due to heating. Even with such a gap, the first contact surface 9a of the first top 7a and the second contact surface 10a of the second top 7b are in contact, so that each top 7a and 7b can airtightly seal the upper part of the feeder 3.

[0055] Electric heating elements 8a and 8b are, for example, resistive heating elements composed of molybdenum disilicide (MoSi2) and the like, that generate heat when electricity is applied. Figure 2 As shown, the electric heating elements 8a and 8b are U-shaped components having a bent portion 8c and two straight portions 8d arranged side by side via the bent portion 8c.

[0056] like Figure 2As shown, the electric heating elements 8a and 8b are supported on the second top 7b via the fixing member 13. However, this is not a limitation; the electric heating elements 8a and 8b may also be supported on the first top 7a. The electric heating elements 8a and 8b include a first electric heating element 8a supported at one end of the second top 7b and a second electric heating element 8b supported at the other end of the second top 7b.

[0057] like Figure 2 , Figure 4 as well as Figure 5 As shown, the second top 7b has a pair of through holes 14a and 14b through which the power supply heating elements 8a and 8b are inserted. Each through hole 14a and 14b extends through the second top 7b in the vertical direction (thickness direction). Figure 4 As shown, each through hole 14a and 14b is circular, but not limited to this shape; they can also be quadrilateral or other shapes.

[0058] The through holes 14a and 14b include a first through hole 14a formed at one end of the second top 7b and a second through hole 14b formed at the other end of the second top 7b. A first electric heating element 8a is inserted through the first through hole 14a, and a second electric heating element 8b is inserted through the second through hole 14b.

[0059] like Figure 2 as well as Figure 5 As shown, the fixing member 13 is mounted on the upper part of the second top 7b. The fixing member 13 supports a portion of the electric heating elements 8a, 8b outside the feeder 3. The fixing member 13 has a protrusion 13a that inserts into the through holes 14a, 14b of the second top 7b. The protrusion 13a functions as a guide for positioning the fixing member 13 relative to the through holes 14a, 14b of the second top 7b.

[0060] To secure the heating elements 8a and 8b to the second top 7b, after installing the heating elements 8a and 8b, which are inserted into the through holes 14a and 14b of the second top 7b, onto the fixing member 13, the protrusion 13a of the fixing member 13 is inserted into the through holes 14a and 14b of the second top 7b. Thus, the fixing member 13 positions the through holes 14a and 14b of the second top 7b, and the heating elements 8a and 8b are secured to the second top 7b. Furthermore, the fixing member 13 airtightly seals the through holes 14a and 14b from the outside of the second top 7b.

[0061] Figures 6 to 8 These are sectional views showing other examples of the top 7a and 7b. Figure 6In the example shown, the first top 7a and the second top 7b are trapezoidal in cross-section. Top 7a has a first surface 7a1 and a second surface 7a2 facing the vertical direction, and a third surface 7a3 and a fourth surface 7a4 formed between the first surface 7a1 and the second surface 7a2. Similarly, top 7b has a first surface 7b1 and a second surface 7b2 facing the vertical direction, and a third surface 7b3 and a fourth surface 7b4 formed between the first surface 7b1 and the second surface 7b2.

[0062] The third surface 7a3 and the fourth surface 7a4 are inclined surfaces formed at an obtuse angle relative to the first surface 7a1 and an acute angle relative to the second surface 7a2. Similarly, the third surface 7b3 and the fourth surface 7b4 are inclined surfaces formed at an obtuse angle relative to the first surface 7b1 and an acute angle relative to the second surface 7b2. For example, the angle (or the angle) formed by the third surface 7a3 and the fourth surface 7a4 relative to the second surface 7a2 (acute angle) is preferably 50° or more and 80° or less.

[0063] According to the above structure, a first width-direction protrusion 9 is formed by the second surface 7a2, the third surface 7a3, and the fourth surface 7a4 of the first top 7a. Additionally, a second width-direction protrusion 10 is formed by the second surface 7b2, the third surface 7b3, and the fourth surface 7b4 of the second top 7b.

[0064] like Figure 6 As shown, when the orientation of the second top 7b is configured to be opposite to that of the first top 7a, the first width-direction protrusion 9 of the first top 7a and the second width-direction protrusion 10 of the second top 7b coincide in the vertical direction. That is, in this example, the third surface 7a3 and the fourth surface 7a4 of the first top 7a become the first contact surface 9a, and the third surface 7b3 and the fourth surface 7b4 of the second top 7b become the second contact surface 10a that contacts the first contact surface 9a.

[0065] exist Figure 7 In the example shown, each of the tops 7a and 7b is configured as a parallelogram shape in cross-section. The first top 7a and the second top 7b use the same shape and the same size components. Each top 7a and 7b has a first surface 7a1, 7b1 and a second surface 7a2, 7b2 facing the vertical direction, and a third surface 7a3, 7b3 and a fourth surface 7a4, 7b4 formed between the first surface 7a1, 7b1 and the second surface 7a2, 7b2.

[0066] The third surfaces 7a3 and 7b3 are inclined surfaces formed at obtuse angles relative to the first surfaces 7a1 and 7b1 and at acute angles relative to the second surfaces 7a2 and 7b2. Similarly, the fourth surfaces 7a4 and 7b4 are inclined surfaces formed at acute angles relative to the first surfaces 7a1 and 7b1 and at obtuse angles relative to the second surfaces 7a2 and 7b2. For example, the angles (acute angles) formed by the third surfaces 7a3 and 7b3 relative to the second surfaces 7a2 and 7b2 (or the angles formed by the fourth surfaces 7a4 and 7b4 relative to the first surfaces 7a1 and 7b1) are preferably 50° or more and 80° or less.

[0067] A first width-direction protrusion 9 is formed by the first surface 7a1 and the fourth surface 7a4 of the first top 7a, and also by the second surface 7a2 and the third surface 7a3. A second width-direction protrusion 10 is formed by the first surface 7b1 and the fourth surface 7b4 of the second top 7b, and also by the second surface 7b2 and the third surface 7b3.

[0068] like Figure 7 As shown, the first width-direction protrusion 9 of the first top 7a and the second width-direction protrusion 10 of the second top 7b coincide in the vertical direction. That is, in this example, the third surface 7a3 and the fourth surface 7a4 of the first top 7a become the first contact surface 9a, and the third surface 7b3 and the fourth surface 7b4 of the second top 7b become the second contact surface 10a that contacts the first contact surface 9a.

[0069] exist Figure 8 In the example shown, each of the top surfaces 7a and 7b has a first surface 7a1, 7b1, a second surface 7a2, 7b2, a third surface 7a3, 7b3, and a fourth surface 7a4, 7b4. In this example, the first surface 7a1, 7b1 and the second surface 7a2, 7b2 are flat surfaces, but the third surface 7a3, 7b3 and the fourth surface 7a4, 7b4 are curved surfaces.

[0070] The third surfaces 7a3 and 7b3 and the fourth surfaces 7a4 and 7b4 each have: a concave portion 15 having a concave curved surface; and a convex portion 16 having a convex curved surface. The curved surfaces of the concave portion 15 and the convex portion 16 are configured as cross-sectional arcs, but the shape of each surface is not limited to this embodiment. The concave portion 15 and the convex portion 16 are formed adjacent to each other in the vertical direction. One end of the curved surface of the concave portion 15 is continuously connected to one end of the curved surface of the convex portion 16.

[0071] In this example, the protrusion 16 formed on the third surface 7a3 and the fourth surface 7a4 of the first top 7a becomes the first width direction protrusion 9, and the protrusion 16 formed on the third surface 7b3 and the fourth surface 7b4 of the second top 7b becomes the second width direction protrusion 10. Moreover, a portion of the protrusion 16 in the first top 7a becomes the first contact surface 9a, and a portion of the protrusion 16 in the second top 7b becomes the second contact surface 10a.

[0072] In this example, the protrusion 16 of the first top 7a enters the recess 15 of the second top 7b, and the protrusion 16 of the second top 7b enters the recess 15 of the first top 7a, so that the first width direction protrusion 9 of the first top 7a is arranged to overlap the second width direction protrusion 10 of the second top 7b in the vertical direction.

[0073] The following describes a method for manufacturing glass fiber Gf using the manufacturing apparatus 1 with the above-described structure. This method includes a melting process, a feeding process, and a forming process.

[0074] In the melting process, the glass raw material Gr is melted in the melting furnace 2 to form molten glass Gm. In the feeding process, the molten glass Gm flows inside the feeder 3 and is supplied to the sleeve 4 provided at the lower part of the feeder 3. In the forming process, the molten glass Gm flows down from the sleeve nozzle provided in the sleeve 4 to form glass fiber Gf.

[0075] According to the feeder 3 of this embodiment described above, by overlapping the first width direction protrusion 9 of the first top 7a and the second width direction protrusion 10 of the second top 7b in the vertical direction, the first top 7a and the second top 7b can be integrated.

[0076] Thus, by integrating the first top 7a and the second top 7b, the moment of inertia of their cross sections can be increased, thereby suppressing the creep deformation of each top 7a and 7b.

[0077] Figure 9 This is a cross-sectional view used to illustrate the previous creep deformation pattern at the top. For example... Figure 9 As shown, the cross-section of the conventional top 7A is rectangular, and adjacent top 7A only contact each other at their end faces 7A1 in the width direction W. That is, the contact surfaces of adjacent top 7A are perpendicular and exert almost no force on each other. Therefore, adjacent top 7A are not integrated but exist independently. In this case, the cross-sectional area of ​​each top 7A is small, so the moment of inertia of the section is also small, making it prone to creep deformation in the length direction. In addition, since adjacent top 7A are not integrated and exist independently, therefore... Figure 9As shown, each of the top 7A is prone to creep deformation at its middle portion in the width direction W. When the top 7A deforms in this way, the end faces 7A1 of the multiple top 7A arranged side by side separate from each other. This state promotes creep deformation in the length direction of each top 7A.

[0078] In contrast, according to the feeder 3 of this embodiment, the first width-direction protrusion 9 (first contact surface 9a) of the first top 7a and the second width-direction protrusion 10 (second contact surface 10a) of the second top 7b are arranged in an overlapping manner. That is, the contact surfaces of the first top 7a and the second top 7b include non-perpendicular surfaces. As a result, the first top 7a and the second top 7b can interact with each other and become integrated. Specifically, the first top 7a bears the load of the second top 7b, and conversely, the second top 7b imparts a load to the first top 7a. As a result, the moment of inertia of the integrated top 7 increases, thereby suppressing creep deformation of the first top 7a and the second top 7b. In addition, the integration of the tops 7a and 7b can suppress creep deformation of the middle portion in the width direction W of each top 7a and 7b. As a result, creep deformation in the length direction of each top 7a and 7b in this embodiment can also be effectively suppressed.

[0079] Especially Figures 3 to 5 The embodiments shown and Figure 6 In the case of the embodiment shown, with Figure 7 as well as Figure 8 Compared to the illustrated embodiment, this is preferable in terms of facilitating regular maintenance of the top 7. For example, if the second top 7b develops defects such as creep deformation or damage, it can be simply pulled upwards and replaced. Furthermore, if the first top 7a develops defects, pulling out the adjacent second top 7b will also pull out the first top 7a. Thus, regular maintenance of the top 7 can be performed by moving only the defective component and its surrounding components.

[0080] It should be noted that the present invention is not limited to the structure of the above-described embodiments, nor is it limited to the effects described above. Various modifications can be made to the present invention without departing from its spirit.

[0081] In the above embodiments, a feeder 3 used in the manufacture of glass fiber Gf is illustrated, but the present invention is not limited to this structure. The present invention can also be applied, for example, to the manufacture of glass plates, glass tubes, and various other glass articles.

[0082] In the above embodiments, electric heating elements 8a and 8b are shown as heating devices for the molten glass Gm in the feeder 3, but the present invention is not limited to this structure. Gas burners and other devices may also be used as heating devices.

[0083] Explanation of reference numerals in the attached figures

[0084] 3 feeder

[0085] 6a First side wall portion

[0086] 6b Second side wall portion

[0087] 7 Top

[0088] 7a First Top

[0089] 7b Second Top

[0090] 8a First electric heating element

[0091] 8b Second electric heating element

[0092] 9. Protrusion in the first width direction

[0093] 9a First contact surface

[0094] 10 Protrusion in the second width direction

[0095] 10a Second contact surface

[0096] 13 Fixed components

[0097] 14a First Through Hole

[0098] 14b Second Through Hole

[0099] Gm molten glass.

Claims

1. A feeder that allows molten glass to flow internally, The feeder is characterized in that... The feeder has a top and a side wall portion supporting the top. The sidewall portion includes a first sidewall portion and a second sidewall portion arranged at predetermined intervals. The top is composed of a long strip-shaped fire-resistant component mounted on the first side wall and the second side wall. The top includes a first top and a second top arranged adjacent to each other. The first top has a first protrusion. The second top has a second protrusion. The first protrusion and the second protrusion overlap in the vertical direction.

2. The feeder according to claim 1, characterized in that, The first protrusion has a first contact surface that is opposite to the second protrusion in the vertical direction. The second protrusion has a second contact surface that contacts the first contact surface in a manner that overlaps with the first contact surface in the vertical direction.

3. The feeder according to claim 1 or 2, characterized in that, The feeder has an electric heating element supported on the top and used to heat the molten glass.

4. The feeder according to claim 3, characterized in that, The top has a through hole through which the electric heating element can be inserted.

5. The feeder according to claim 4, characterized in that, The feeder includes a fixing member for fixing the electric heating element, which is inserted through the through hole, to the top.

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