Coating apparatus and coating method

Abstract

The coating device has: a fiber passage that passes the glass fiber in a vertically downward direction; a first flow path that is a flow path that passes the first resin toward the fiber passage, has a first branch passage that horizontally branches the first resin that moves in a horizontal direction; a first temperature adjuster that is arranged along the first flow path and performs temperature adjustment of the first flow path; a second flow path that is a flow path that passes the second resin toward the fiber passage, has a second branch passage that horizontally branches the second resin that moves in a horizontal direction, and is located at a position that is lower than the first flow path; and a second temperature adjuster that is arranged along the second flow path and performs temperature adjustment of the second flow path.

Description

Technical Field

[0001] This invention relates to a coating apparatus and a coating method.

[0002] This application claims priority based on Japanese Patent Application No. 2021-111389, filed on July 5, 2021, the contents of which are incorporated herein by reference in their entirety. Background Technology

[0003] Japanese Patent Application Publication No. 2019-99392 discloses a resin coating apparatus. This apparatus includes: a first mold that coats a first resin onto the outer side of drawn glass fibers; and a second mold that coats a second resin onto the outer side of the first resin. The first and second molds are integrally assembled, coating the first and second resins onto the glass fibers together. Furthermore, the apparatus includes a first fluid circulation unit and a second fluid circulation unit. The first fluid circulation unit is disposed around the first mold, and the temperature of the first resin supplied to the first mold is adjusted by controlling the temperature of the circulating fluid. The second fluid circulation unit is disposed around the second mold, and the temperature of the second resin supplied to the second mold is adjusted by controlling the temperature of the circulating fluid. Summary of the Invention

[0004] An embodiment of the present invention relates to a coating apparatus comprising: an optical fiber path through which glass fibers pass in a vertically downward direction; a first flow path through which a first resin flows toward the optical fiber path, having a first branch path that horizontally branches the first resin moving in a horizontal direction; a first temperature regulator disposed along the first flow path for adjusting the temperature of the first flow path; a second flow path through which a second resin flows toward the optical fiber path, having a second branch path that horizontally branches the second resin moving in a horizontal direction, located at a position lower than the first flow path; and a second temperature regulator disposed along the second flow path for adjusting the temperature of the second flow path. Attached Figure Description

[0005] Figure 1 This is a diagram illustrating the structure of an optical fiber manufacturing apparatus as described in an example.

[0006] Figure 2 This is a schematic block diagram representing a resin coating apparatus.

[0007] Figure 3 This is a schematic diagram showing the metering pump of the resin coating device.

[0008] Figure 4 This is a flowchart illustrating the optical fiber manufacturing process. Detailed Implementation

[0009] [The problem the invention aims to solve]

[0010] Regarding the technology involved in the aforementioned resin coating apparatus, it is desirable to be able to uniformly adjust the flow of resin coated onto the glass fiber in the circumferential direction. Furthermore, it is desirable to reduce the vertical dimension of the apparatus.

[0011] [The effects of the invention]

[0012] According to the coating apparatus of the present invention, the flow of resin applied to glass fibers can be uniformly adjusted in the circumferential direction of the glass fibers, and the size of the apparatus in the vertical direction can be reduced.

[0013] [Description of embodiments of the present invention]

[0014] First, embodiments of the present invention will be described. One embodiment of the coating apparatus includes: an optical fiber path through which glass fibers pass in a vertically downward direction; a first flow path through which a first resin flows toward the optical fiber path, having a first branch path that horizontally branches the first resin moving in a horizontal direction; a first temperature regulator disposed along the first flow path for adjusting the temperature of the first flow path; a second flow path through which a second resin flows toward the optical fiber path, having a second branch path that horizontally branches the second resin moving in a horizontal direction, located at a position lower than the first flow path; and a second temperature regulator disposed along the second flow path for adjusting the temperature of the second flow path.

[0015] In the above-described coating apparatus, a first resin, after being temperature-adjusted by a first temperature regulator and flowing through the first flow path, is coated onto the glass fiber passing through the optical fiber path. Furthermore, a second resin, after being temperature-adjusted by a second temperature regulator and flowing through the second flow path, is further coated onto the glass fiber coated with the first resin. The first and second flow paths are respectively formed with a first branch path and a second branch path that horizontally branches the resin. Therefore, flow paths can be formed from multiple circumferential positions toward the optical fiber path. Thus, the flow of the resin coated onto the glass fiber can be uniformly adjusted circumferentially around the glass fiber. Furthermore, since the branch paths branch only in the horizontal direction, the vertical dimension of the apparatus can be reduced.

[0016] In one example, the first flow path and the first temperature regulator can be formed with a first annular body having a ring shape arranged around the optical fiber path. The second flow path and the second temperature regulator can be formed with a second annular body having a ring shape arranged below the first annular body with the optical fiber path as the center. In this structure, it is easy to arrange each flow path and each temperature regulator equally around the optical fiber path.

[0017] A heat insulation layer can be formed between the first annular body and the second annular body in the vertical direction. This structure suppresses the influence of the heat from the first temperature regulator on the second annular body and the influence of the heat from the second temperature regulator on the first annular body.

[0018] The first and second flow paths can be located vertically, between the first and second temperature regulators. The first flow path adjusts the temperature through the first temperature regulator, and the second flow path adjusts the temperature through the second temperature regulator. This structure suppresses the influence of the heat from the first temperature regulator on the second annular body and the heat from the second temperature regulator on the first annular body.

[0019] The heat source for the first temperature regulator can be a heater arranged along the first flow path, and the heat source for the second temperature regulator can be a third flow path arranged along the second flow path for the flow of temperature-adjusted fluid. In this structure, for example, it is possible to easily adjust the temperature of the first resin flowing in the first flow path to be higher than that of the second resin.

[0020] The first branch passage may have one inlet and two outlets, with the cross-sectional area of ​​each of the two outlets being half the cross-sectional area of ​​the inlet. In this structure, the first resin can be branched equally through the first branch passage.

[0021] The first branch passage may have one inlet and multiple outlets, where the cross-sectional area of ​​the inlet is equal to the sum of the cross-sectional areas of the outlets. In this structure, the first resin can be branched equally through the first branch passage.

[0022] The first flow path may include four outlets branching off from the first branch path, with the four outlets evenly arranged circumferentially around the optical fiber path. In this structure, the flow of the first resin near the optical fiber path tends to become uniform circumferentially. Furthermore, "evenly arranged circumferentially" not only means strictly equal spacing, but also includes approximately equal spacing that can be considered substantially equal.

[0023] The second branch passage can have one inlet and two outlets, with the cross-sectional area of ​​each of the two outlets being half the cross-sectional area of ​​the inlet. In this structure, the second resin can be branched equally through the second branch passage.

[0024] The second branch passage can have one inlet and multiple outlets, where the cross-sectional area of ​​the inlet is equal to the sum of the cross-sectional areas of the outlets. In this structure, the second resin can be branched equally through the second branch passage.

[0025] The second flow path can include four outlets branching off from the second branch path, with the four outlets evenly arranged circumferentially around the optical fiber path. In this structure, the flow of the second resin near the optical fiber path easily becomes uniform circumferentially. Furthermore, in this case, "evenly arranged circumferentially" not only means strictly equal spacing, but also includes approximately equal spacing that can be considered substantially equal.

[0026] One embodiment of the coating method includes the following steps: passing glass fibers vertically downward through an optical fiber path; allowing a first resin to flow through a horizontally branched first flow path, adjusting the temperature of the first resin to a first temperature using a first temperature regulator; allowing a second resin to flow through a horizontally branched second flow path located lower than the first flow path, adjusting the temperature of the second resin to a second temperature using a second temperature regulator; coating the glass fibers moving within the optical fiber path with the first resin flowing through the first flow path; and coating the glass fibers moving within the optical fiber path coated with the first resin with the second resin flowing through the second flow path.

[0027] In the above coating method, a first resin, flowing through a first flow path and adjusted to a first temperature, is coated onto the glass fiber passing through the optical fiber path. Furthermore, a second resin, flowing through a second flow path and adjusted to a second temperature, is further coated onto the glass fiber coated with the first resin. The resin is branched in the first and second flow paths, thus forming flow paths from multiple circumferential positions toward the optical fiber path. Therefore, the flow of the resin coated on the glass fiber can be uniformly adjusted circumferentially around the glass fiber. Additionally, by branching the resin only in the horizontal direction, the vertical dimension of the device can be reduced.

[0028] [Details of embodiments of the present invention]

[0029] Hereinafter, specific examples of the coating apparatus according to the present invention will be described with reference to the accompanying drawings. The coating apparatus is an apparatus for manufacturing optical fiber strands on which resin is coated on the surface of glass fibers; it may refer to the entire optical fiber manufacturing apparatus or a part thereof. Furthermore, the present invention is not limited to these examples, but is shown in the claims, encompassing all modifications equivalent to and within the scope of the claims. In the following description, the same reference numerals are used for the same elements in the description of the drawings, and repeated descriptions are omitted.

[0030] Figure 1 The structure of an example optical fiber manufacturing apparatus 1 is shown. For example... Figure 1As shown, the optical fiber manufacturing apparatus 1 is an apparatus for manufacturing optical fiber line F. The drawing furnace 11, forced cooling device 12, outer diameter measuring device 13, resin coating device 100, thickness deviation measuring device 16, UV furnace 17, outer diameter measuring device 18, guide roller 20, winch 21 and winding spool 22 are arranged sequentially along the path of glass fiber F11 and optical fiber line F. The optical fiber line F has: glass fiber F11 including core and cladding; and resin coating.

[0031] In the optical fiber manufacturing apparatus 1, the initial movement direction of the optical fiber line F is set to vertical. After the guide roller 20, the movement direction of the optical fiber line F is set to horizontal or oblique. The drawing furnace 11 draws a preform (glass matrix) 10, primarily composed of quartz glass, into glass fibers F11, comprising a core and a cladding. The drawing furnace 11 has a heater disposed between the preform 10 and the drawing furnace 11. The heater can surround the preform 10. The ends of the preform 10 melt due to heating by the heater and are drawn into glass fibers F11. The drawn glass fibers F11 move downwards in the vertical direction.

[0032] The forced cooling device 12 cools the drawn glass fiber F11. The forced cooling device 12 has sufficient length in the vertical direction to adequately cool the glass fiber F11. The forced cooling device 12 has, for example, an air intake and an exhaust port (not shown) for cooling the glass fiber F11; cooling gas is introduced through the air intake to cool the glass fiber F11.

[0033] The outer diameter measuring device 13 measures the outer diameter of the cooled glass fiber F11. For example, the outer diameter measuring device 13 irradiates light onto the glass fiber F11, captures the light after it passes through the glass fiber F11, and thereby measures the outer diameter of the glass fiber F11.

[0034] The resin coating apparatus 100 applies resin to the glass fiber F11. The resin coating apparatus 100 holds two liquid resins that are cured by ultraviolet light. In the resin coating apparatus 100, the glass fiber F11 passes through the held resin, thereby sequentially coating the surface of the glass fiber F11 with an inner layer resin (first resin 14) and an outer layer resin (second resin 15). Details regarding the resin coating apparatus 100 will be described later.

[0035] The thickness deviation measuring device 16 measures the deviation of the center position of the glass fiber F11 relative to the center position of the fiber optic line F. In other words, the thickness deviation measuring device 16 measures the thickness offset of the glass fiber F11 and the inner and outer resin layers coated on its periphery. For example, the thickness deviation measuring device 16 illuminates the fiber optic line F with light, captures the light after it passes through the fiber optic line F, and thereby measures the center deviation.

[0036] UV oven 17 is a resin curing section that cures two types of resin (first resin 14 and second resin 15) coated on the surface of glass fiber F11 by irradiating them with ultraviolet light. Glass fiber F11 coated with the two types of resin 14 and 15 passes through UV oven 17, thereby forming an optical fiber line F having glass fiber F11 and two cladding layers.

[0037] The outer diameter measuring instrument 18 measures the outer diameter of the fiber optic cable F formed by coating glass fiber F11 with resin. The method for measuring the outer diameter is the same as that for the outer diameter measuring instrument 13 described above.

[0038] The guide roller 20 guides the fiber optic cable F to move in a predetermined direction. The fiber optic cable F changes direction via the guide roller 20 and is picked up by the winch 21 and fed to the winding spool 22. The winding spool 22 winds the completed fiber optic cable F.

[0039] Next, the resin coating apparatus 100 will be described in more detail. One example of the resin coating apparatus 100 is that it sequentially coats two resins 14 and 15 onto glass fiber while adjusting them to their respective different temperatures. Figure 2 This is a schematic cross-sectional view of a longitudinal section of a resin coating apparatus 100, illustrating an example. Figure 3 It is along Figure 2 A schematic diagram of the cross section of line III-III. Figure 4 It is along Figure 2 A schematic diagram of the cross section of line IV-IV.

[0040] like Figure 2 As shown, an example resin coating apparatus 100 is fixed to a worktable 101 positioned at a predetermined height within an optical fiber manufacturing apparatus 1. The worktable 101 has a plate shape with the vertical direction defined as the thickness direction. An opening 101a for mounting the resin coating apparatus 100 is formed in the center of the worktable 101. As an example, the opening 101a may be circular when viewed from above or below.

[0041] The resin coating apparatus 100 includes an inner sleeve 102, an outer sleeve 103, and a mold 105. The inner sleeve 102 includes a main body portion 111 and a support plate 113. The main body portion 111 is cylindrical in shape with a central axis 100a along the vertical direction. When viewed axially, the outer diameter of the main body portion 111 is smaller than the diameter of the opening 101a of the worktable 101. A plurality of first through holes 112a and a plurality of second through holes 112b are formed in the main body portion 111, penetrating through the sidewalls.

[0042] The first through holes 112a are formed at equal intervals along the circumference of the main body 111, and are formed at the same height position. In the example shown in the figure, four first through holes 112a are formed. The second through holes 112b are formed at equal intervals along the circumference of the main body 111, and are formed at the same height position. In the example shown in the figure, four second through holes 112b are formed.

[0043] The height position of forming the second through hole 112b is separated downward from the height position of forming the first through hole 112a. At the midpoint between the height position of forming the first through hole 112a and the height position of forming the second through hole 112b, the outer peripheral surface of the main body portion 111 has a circumferentially continuous recess 111b.

[0044] The support plate 113 is located at the lower end of the main body portion 111. The support plate 113 includes, for example, a small-diameter portion 113a and a large-diameter portion 113b. The small-diameter portion 113a is plate-shaped, extending radially outward from the lower end of the main body portion 111. The shape of the small-diameter portion 113a is circular when viewed from above or below. The outer diameter of the small-diameter portion 113a may be substantially the same as the diameter of the opening 101a of the worktable 101.

[0045] The large-diameter portion 113b is located above the small-diameter portion 113a. The large-diameter portion 113b and the small-diameter portion 113a are adjacent to each other. The large-diameter portion 113b and the small-diameter portion 113a can be integrally formed. The large-diameter portion 113b is plate-shaped, extending radially outward from the outer periphery of the main body portion 111. The shape of the large-diameter portion 113b can be circular when viewed from above or below. The outer diameter of the large-diameter portion 113b is larger than the outer diameter of the small-diameter portion 113a, that is, larger than the diameter of the opening 101a of the worktable 101. The small-diameter portion 113a fits into the opening 101a of the worktable 101, and the large-diameter portion 113b is placed on the upper surface 101b of the worktable 101, thereby fixing the resin coating apparatus 100 to the worktable 101.

[0046] Mold 105 is disposed within the inner space of inner sleeve 102. Mold 105 includes a first mold 120, a second mold 130, and a through-hole point 140. The first mold 120 is cylindrical. The first mold 120 and the main body 111 of inner sleeve 102 share a common axis (central axis 100a). The outer diameter of the first mold 120 can be the same as the inner diameter of inner sleeve 102. The die hole 120S of the cylindrical first mold 120 forms part of the optical fiber path 105S for glass fiber F11 to pass through. The first mold 120 is positioned between the height positions of the first through-hole 112a and the second through-hole 112b.

[0047] The second mold 130 is disposed adjacent to the lower side of the first mold 120. The second mold 130 is cylindrical. The second mold 130 and the main body portion 111 of the inner sleeve 102 share a common axis (central axis 100a). The outer diameter of the second mold 130 can be the same as the inner diameter of the inner sleeve 102. The end face of the second mold 130 on the side of the first mold 120 includes a radially inner side, i.e., an inner portion 131, and a radially outer side, i.e., an outer portion 132. The mold hole 130S of the cylindrical second mold 130 is located at the center of the inner portion 131. The mold hole 130S forms part of the optical fiber path 105S for the glass fiber F11 to pass through. The height of the inner portion 131 is lower than the height of the outer portion 132. Therefore, when the second mold 130 is adjacent to the first mold 120, the outer portion 132 contacts the first mold 120, and a gap 131S is formed between the inner portion 131 and the first mold 120. A generally cylindrical recess is formed on the lower surface of the second mold 130. The mold hole 130S communicates with this recess.

[0048] A groove 133 is formed between the inner portion 131 and the outer portion 132 of the second mold 130, along the outer periphery of the inner portion 131 and the inner periphery of the outer portion 132. Multiple flow paths 136 communicating with the groove 133 are formed in the second mold 130. The multiple flow paths 136 connect the outer peripheral surface of the second mold 130 and the groove 133. The multiple flow paths 136 are evenly arranged circumferentially when viewed from the axial direction. In the example shown, there are four flow paths 136, each connected to the second through hole 112b when the second mold 130 is positioned within the inner sleeve 102. The multiple flow paths 136 extend horizontally along the radial direction of the second mold 130.

[0049] The through-mold 140 is disposed adjacent to the upper side of the first mold 120. The through-mold 140 is cylindrical. The through-mold 140 and the main body portion 111 of the inner sleeve 102 share a common axis (central axis 100a). The outer diameter of the through-mold 140 can be the same as the inner diameter of the inner sleeve 102. The end face of the through-mold 140 on the first mold 120 side includes a radially inner side, i.e., an inner portion 141, and a radially outer side, i.e., an outer portion 142. The through-mold hole 140S of the cylindrical through-mold 140 is located at the center of the inner portion 141. The through-mold hole 140S forms part of the optical fiber passage 105S for the glass fiber F11 to pass through. In the example shown in the figure, a fiber optic path 105S for glass fiber F11 to pass through is formed by the through-mold hole 140S of the fixed mold 140, the mold hole 120S of the first mold 120, and the mold hole 130S of the second mold 130 in the vertically downward direction. The fiber optic path 105S extends vertically with the central axis 100a as the center.

[0050] The height of the inner portion 141 of the through-mold 140 is higher than the height of the outer portion 142. Therefore, when the through-mold 140 is adjacent to the first mold 120, the outer portion 142 contacts the first mold 120, forming a gap 141S between the inner portion 141 and the first mold 120. A generally conical recess is formed on the upper surface of the through-mold 140. The through-mold hole 140S communicates with this recess.

[0051] A groove 143 is formed between the inner portion 141 and the outer portion 142 of the through-mold 140, along the outer periphery of the inner portion 141 and the inner periphery of the outer portion 142. Multiple flow paths 146 communicating with the groove 143 are formed in the through-mold 140. The multiple flow paths 146 connect the outer peripheral surface of the through-mold 140 and the groove 143. The multiple flow paths 146 are evenly arranged circumferentially when viewed from the axial direction. In the illustrated example, there are four flow paths 146, each connected to the first through hole 112a when the through-mold 140 is positioned within the inner sleeve 102. The multiple flow paths 146 extend horizontally along the radial direction of the through-mold 140.

[0052] The outer sleeve 103 is fixed to the outer circumferential surface of the inner sleeve 102. The outer sleeve 103 includes a first annular body 150 and a second annular body 170. The first annular body 150 has an annular shape arranged centered on the optical fiber path 105S (central axis 100a). In one example, the first annular body 150 has a cylindrical shape with an inner diameter of the same size as the outer diameter of the inner sleeve 102. The first annular body 150 includes a first flow path 151 and a first temperature regulator 160.

[0053] The first flow path 151 allows the first resin 14 to flow toward the optical fiber passage 105S. The first flow path 151 has a supply port 152 for supplying the first resin 14 and an outlet port 153 connected to the first through hole 112a of the inner sleeve 102. The first resin 14 supplied from the supply port 152 is discharged from the outlet port 153, thereby being supplied to the first through hole 112a. The first resin 14 supplied to the first through hole 112a reaches the optical fiber passage 105S via the flow path 146, the groove 143, and the gap 141S through the mold 140.

[0054] The first flow path 151 has a branching passage that allows the first resin 14, which moves in the horizontal direction, to branch horizontally. The first flow path 151 extends horizontally inside the first annular body 150. The first flow path 151 branches into multiple flow paths through the branching passage in a manner corresponding to the number of first through holes 112a formed in the inner sleeve 102. Furthermore, the first flow path 151 may not be strictly horizontal, as long as it is substantially horizontal. For example, the first flow path 151 may be formed at an angle of approximately -3° to 3° relative to the horizontal.

[0055] The first flow path 151 in the example diagram includes an upstream branch path 154 (the first branch path on the upstream side) and a downstream branch path 155 (the first branch path on the downstream side). The upstream branch path 154 branches off from the flow path 151a following the supply port 152 into multiple paths. The downstream branch path 155 further branches off from the multiple flow paths 151b branching off from the upstream branch path 154 into multiple paths. In the example diagram, both the upstream branch path 154 and the downstream branch path 155 have one inlet and two outlets. That is, the upstream branch path 154 and the downstream branch path 155 branch the flow path into two paths.

[0056] like Figure 3 As shown, flow path 151a, connected to supply port 152, branches into two flow paths 151b via upstream branch passage 154. The two branched flow paths 151b extend in opposite directions circumferentially. The lengths of the two flow paths 151b are equal. The branched flow paths 151b are connected to downstream branch passages 155. The downstream branch passages 155 are opposite to each other, separated by optical fiber passage 105S. The downstream branch passages 155 cause flow paths 151b to branch circumferentially. Specifically, the downstream branch passages 155 extend radially inward from the end of flow path 151b, connecting to two flow paths 151c that branch at that location and extend in opposite directions circumferentially. The lengths of the two flow paths 151c are equal. The four flow paths 151c branching from the pair of opposite downstream branch passages 155 extend circumferentially with their ends evenly positioned at their ends. The four flow paths 151c are connected to the four first through holes 112a via the outlet 153.

[0057] The cross-sectional area of ​​the inlet of the branch path is equal to the sum of the cross-sectional areas of the individual outlets. That is, in the example shown in the figure, the cross-sectional area of ​​each of the two flow paths 151b (outlets) connected to the upstream branch path 154 can be half the cross-sectional area of ​​the flow path 151a (inlet) connected to the upstream branch path 154. Similarly, the cross-sectional area of ​​each of the two flow paths 151c (outlets) connected to the downstream branch path 155 can be half the cross-sectional area of ​​the flow path 151b (inlet) connected to the downstream branch path 155. Furthermore, the cross-sectional area of ​​the inlet of the branch path only needs to be substantially equal to the sum of the cross-sectional areas of the individual outlets, for example, an error of less than 10% is allowed. Similarly, the cross-sectional area of ​​each of the individual outlets only needs to be substantially equal, for example, an error of less than 10% is allowed.

[0058] A first temperature regulator 160 is configured along a first flow path 151 to regulate the temperature of the first resin 14 flowing through the first flow path 151. In one example, the heat source for the first temperature regulator 160 may be a heater 162 configured along the first flow path 151. The heater 162 may, for example, include a resistive element that is heated by electricity supplied from an external source. The heater 162 is configured horizontally at a height offset to either side of the first flow path 151 in the up-down direction. In the example shown, the heater 162 is configured on the upper side of the first flow path 151. Furthermore, for example, when viewed from above or below, the ends 162a and 162b of the heater 162 are located on the opposite side of the supply port 152, centered on the optical fiber passage 105S. The heater 162 extends circumferentially from end 162a to end 162b. In the radial direction, the heater 162 extends from the inner edge of the flow path 151c to the outer edge of the flow path 151b. Furthermore, in the circumferential direction, the heater 162 extends at least to the area forming the flow paths 151b and 151c. Thus, when viewed from above or below, the positions of the flow paths 151b and 151c overlap with the position of the heater 162.

[0059] The second annular body 170 has an annular shape arranged centered on the optical fiber path 105S. In one example, the second annular body 170 has a cylindrical shape with an inner diameter of the same size as the outer diameter of the inner sleeve 102. The second annular body 170 includes a second flow path 171 and a second temperature regulator 180.

[0060] The second flow path 171 allows the second resin 15 to flow toward the optical fiber passage 105S. The second flow path 171 has a supply port 172 for supplying the second resin 15, and a discharge port 173 connected to the second through-hole 112b of the inner sleeve 102. The second resin 15 supplied from the supply port 172 is discharged from the discharge port 173, thereby being supplied to the second through-hole 112b. The second resin 15 supplied to the second through-hole 112b reaches the optical fiber passage 105S via the flow path 136, groove 133, and gap 131S of the second mold 130.

[0061] The second flow path 171 has a branching passage that allows the second resin 15, which moves in the horizontal direction, to branch horizontally. In one example, the second flow path 171 extends horizontally inside the second annulus 170. The second flow path 171 branches into multiple flow paths via the branching passage in a manner corresponding to the number of second through holes 112b formed in the inner sleeve 102. Furthermore, the second flow path 171 does not need to be strictly horizontal, as long as it is substantially horizontal. For example, the second flow path 171 can be formed at an angle of approximately -3° to 3° relative to the horizontal.

[0062] The second flow path 171 in the illustration includes an upstream branch path 174 (the second branch path on the upstream side) and a downstream branch path 175 (the second branch path on the downstream side). The upstream branch path 174 branches off from the flow path 171a following the supply port 172 into multiple paths. The downstream branch path 175 further branches off from the multiple flow paths 171b branching off from the upstream branch path 174 into multiple paths. In the illustration, both the upstream branch path 174 and the downstream branch path 175 have one inlet and two outlets. That is, the upstream branch path 174 and the downstream branch path 175 branch the flow path into two paths.

[0063] like Figure 4As shown, flow path 171a, connected to supply port 172, branches into two flow paths 171b via upstream branch passage 174. The branched flow paths 171b extend in opposite directions circumferentially. The two branched flow paths 171b are each connected to a downstream branch passage 175. The lengths of the two flow paths 171b are equal. The downstream branch passages 175 are opposite to each other, separated by optical fiber passage 105S. The downstream branch passages 175 cause flow paths 171b to branch circumferentially. Specifically, the downstream branch passage 175 extends radially inward from the end of flow path 171b, connecting to two flow paths 171c that branch at that location and extend in opposite directions circumferentially. The lengths of the two flow paths 171c are equal. The four flow paths 171c branching from the pair of opposite downstream branch passages 175 extend circumferentially with their ends evenly positioned at their ends. The four flow paths 171c are connected to the four second through holes 112b via the outlet 173.

[0064] The cross-sectional area of ​​the inlet of each branch path is equal to the sum of the cross-sectional areas of the individual outlets. That is, in the example shown in the figure, it can be half the cross-sectional area of ​​the flow path 171a (inlet) connected to the upstream branch path 174. Similarly, the cross-sectional area of ​​each of the two flow paths 171c (outlets) connected to the downstream branch path 175 can be half the cross-sectional area of ​​the flow path 171b (inlet) connected to the downstream branch path 175.

[0065] The second temperature regulator 180 is configured along the second flow path 171 to adjust the temperature of the second resin flowing through the second flow path 171. In one example, the heat source of the second temperature regulator 180 may be a flow path through which the temperature-adjusted fluid flows (hereinafter referred to as a temperature-adjusting water flow path). The fluid may be temperature-adjusted water (hereinafter referred to as temperature-adjusting water). The second temperature regulator 180 is configured along the second flow path 171.

[0066] The temperature-regulating water flow path 182 (the third flow path) is horizontally positioned at a height offset to either side of the second flow path 171 in the vertical direction. In the example shown, the temperature-regulating water flow path 182 is positioned below the second flow path 171. Therefore, the first flow path 151 and the second flow path 171 are located between the first temperature regulator 160 and the second temperature regulator 180 in the vertical direction.

[0067] The ends 182a and 182b of the temperature-regulating water flow path 182 are located on the opposite side of the supply port 172, centered on the optical fiber passage 105S. The temperature-regulating water flow path 182 extends circumferentially from end 182a to end 182b. Temperature-regulating water flowing through the temperature-regulating water flow path 182 is supplied from end 182a and discharged from end 182b, for example. Connection ends 181 for supplying or discharging temperature-regulating water are provided at ends 182a and 182b respectively. Temperature-regulating water discharged from end 182b can be re-temperature-adjusted and supplied to end 182a. Radially, the temperature-regulating water flow path 182 extends from the inner edge of flow path 171c to the outer edge of flow path 171b. Circumferentially, the temperature-regulating water flow path 182 extends at least to the area forming flow paths 171b and 171c. Therefore, when viewed from above or below, the positions of flow paths 171b and 171c overlap with the position of temperature-regulating water flow path 182.

[0068] A heat insulation layer 191 is formed between the first annular body 150 and the second annular body 170 in the vertical direction. In the example shown, the first annular body 150 and the second annular body 170 are separated from each other in the vertical direction. That is, an air layer that functions as the heat insulation layer 191 is formed between the first annular body 150 and the second annular body 170. Furthermore, in one example, the air layer is formed along the position of the recess 111b formed on the outer peripheral surface of the inner sleeve 102.

[0069] Next, the method for manufacturing optical fibers using the optical fiber manufacturing apparatus 1 will be described. In the optical fiber manufacturing apparatus 1 described above, a preform 10, which will become the parent material, is first placed in a drawing furnace 11. The preform 10 is then melted by a heater. The molten preform 10 is drawn into fibers to form glass fibers F11. The glass fibers F11 move downwards in the vertical direction and pass through a forced cooling device 12. The drawn glass fibers F11 are cooled in the forced cooling device 12.

[0070] The cooled glass fiber F11 passes through the outer diameter measuring device 13 to measure its outer diameter. The glass fiber F11 with its outer diameter measured moves downwards in the vertical direction and passes through the resin coating device 100.

[0071] In the resin coating apparatus 100, a first resin 14 is supplied to a first flow path 151 at a predetermined flow rate, and a second resin 15 is supplied to a second flow path 171 at a predetermined flow rate. The first resin 14 supplied to the first flow path 151 is adjusted to a predetermined first temperature by a first temperature regulator 160, and the second resin 15 supplied to the second flow path 171 is adjusted to a predetermined second temperature by a second temperature regulator 180. The temperatures adjusted by the first temperature regulator 160 and the temperatures adjusted by the second temperature regulator 180 are different from each other.

[0072] In the resin coating apparatus 100, the temperature of the resin is adjusted, thereby adjusting the viscosity of the resin to a specified range. Generally, the viscosity (Pa·s) of the resin depends on the temperature; the higher the temperature, the lower the viscosity, and the lower the temperature, the higher the viscosity. In the optical fiber manufacturing apparatus 1 described above, by adjusting the viscosity of the resin to a specified range, the resin can be appropriately coated onto the peripheral surface of the glass fiber F11. In one example, the first resin 14, in order to absorb external strain in contact with the glass fiber F11, requires flexibility and tends to have a high viscosity. On the other hand, the second resin 15, in order to withstand external stress, requires hardness and toughness and tends to have a low viscosity. That is, under the same temperature conditions, the viscosity of the first resin 14 is higher than that of the second resin 15. In this case, in order to adjust the viscosity of the first resin 14 and the second resin 15 to a range suitable for coating, the temperature of the first resin 14 needs to be adjusted to a higher temperature than the temperature of the second resin 15. Therefore, in one example of the resin coating apparatus 100, the first temperature is set higher than the second temperature.

[0073] In one example of a resin coating apparatus 100, the viscosity of the first resin 14 and the second resin 15 when coating glass fiber F11 is adjusted to approximately 0.8 Pa·s to 2.0 Pa·s. As an example, when the first temperature, adjusted by the first temperature regulator 160, is approximately 35°C to 70°C, and the second temperature, adjusted by the second temperature regulator 180, is approximately 30°C to 45°C, the first resin 14 and the second resin 15 can meet the aforementioned viscosity requirements. Furthermore, in this case, the viscosity ratio of the first resin 14 to the second resin 15 (viscosity of the second resin / viscosity of the first resin) can, for example, be approximately 0.5 to 0.9.

[0074] After temperature adjustment, the first resin 14 flows into the optical fiber passage 105S via the first flow path 151, the first through hole 112a, the flow path 146, the groove 143, and the gap 141S. The first resin 14 flows from the plurality of flow paths 146 arranged evenly in the circumferential direction into the groove 143 and the gap 141S that surround the entire circumferential area of ​​the optical fiber passage 105S. As a result, the flow of the first resin 14 near the optical fiber passage 105S becomes uniform in the circumferential direction. Similarly, the second resin 15 flows into the optical fiber passage 105S via the second flow path 171, the second through hole 112b, the flow path 136, the groove 133, and the gap 131S. The second resin flows from the flow path 136 arranged evenly in the circumferential direction into the groove 133 and the gap 131S that surround the entire circumferential area of ​​the optical fiber passage 105S. As a result, the flow of the second resin 15 near the optical fiber path 105S becomes uniform in the circumferential direction.

[0075] If the vertically downward-moving glass fiber F11 passes through the optical fiber path 105S, a first resin 14 is first applied to the peripheral surface of the glass fiber F11. Furthermore, as the glass fiber F11 moves downward, a second resin 15 is further applied on top of the first resin 14 applied to the glass fiber F11.

[0076] Next, the deviation of the center position of the glass fiber F11 from the center position of the fiber optic cable F is measured using a thickness deviation measuring device 16. Furthermore, the glass fiber F11, coated with resins 14 and 15, moves vertically downwards and passes through a UV furnace 17. As the glass fiber F11 passes through the UV furnace 17, it is irradiated with ultraviolet light by the resins 14 and 15, forming the fiber optic cable F. The fiber optic cable F moves in a predetermined direction via a guide roller 20, is picked up by a winch 21, and is conveyed to a winding spool 22.

[0077] In the resin coating apparatus 100 of the optical fiber manufacturing apparatus 1 described above, upstream branch passages 154 and downstream branch passages 155 (first branch passages) and upstream branch passages 174 and downstream branch passages 175 (second branch passages) that horizontally branch the resin are formed in the first flow path 151 and the second flow path 171, respectively. Therefore, flow paths can be formed from multiple circumferential positions toward the optical fiber path 105S. Thus, the flow of resin coated onto the glass fiber F11 can be uniformly adjusted circumferentially around the glass fiber F11. Furthermore, since the flow paths including each branch passage branch only in the horizontal direction, the vertical dimension of the resin coating apparatus 100 can be reduced. This suppresses the overall increase in height of the optical fiber manufacturing apparatus 1.

[0078] In one example, a first flow path 151 and a first temperature regulator 160 are formed on a first annular body 150 having a ring shape arranged around the optical fiber path 105S. Additionally, a second flow path 171 and a second temperature regulator 180 are formed on a second annular body 170 having a ring shape arranged below the first annular body 150 with the optical fiber path 105S as its center. With this structure, the flow paths 151, 171, and the temperature regulators 160, 180 can be easily and evenly arranged around the optical fiber path 105S.

[0079] In one example, a heat insulation layer 191 is formed between the first annular body 150 and the second annular body 170 in the vertical direction. This structure suppresses the influence of the first temperature regulator 160 formed in the first annular body 150 on the second annular body 170. Furthermore, it suppresses the influence of the second temperature regulator 180 formed in the second annular body 170 on the first annular body 150.

[0080] Furthermore, the first flow path 151 and the second flow path 171 are located vertically between the first temperature regulator 160 and the second temperature regulator 180. The first flow path 151 adjusts the temperature through the first temperature regulator 160, and the second flow path 171 adjusts the temperature through the second temperature regulator 180. This structure suppresses the influence of the first temperature regulator 160 formed in the first annular body 150 on the second annular body 170. Similarly, it suppresses the influence of the second temperature regulator 180 formed in the second annular body 170 on the first annular body 150.

[0081] In one example, the first temperature regulator 160 uses a heater 162 arranged along the first flow path 151 as a heat source. Additionally, the second temperature regulator 180 uses a temperature-regulating water flow path 182 arranged along the second flow path 171, through which temperature-regulated fluid flows, as a heat source. In this configuration, for example, it is possible to easily adjust the temperature of the first resin 14 flowing through the first flow path 151 to be higher than that of the second resin 15.

[0082] The upstream branch passage 154 has a flow path 151a as an inlet and two flow paths 151b as outlets. The cross-sectional area of ​​each flow path 151b is half that of flow path 151a. Similarly, the downstream branch passage 155 has a flow path 151b as an inlet and two flow paths 151c as an outlet. The cross-sectional area of ​​each flow path 151c is half that of flow path 151b. Furthermore, the cross-sectional area of ​​the inlet of each branch passage is equal to the sum of the cross-sectional areas of their respective outlets. In this structure, the first resin 14 can be evenly branched through each branch passage. The same effect is also achieved in the upstream branch passage 174 and the downstream branch passage 175.

[0083] The first flow path 151 includes four outlets, namely flow paths 151c, branching out through the upstream branch path 154 and the downstream branch path 155. The four flow paths 151c are evenly arranged circumferentially with the optical fiber path 105S as the center. With this structure, the flow of the first resin 14 near the optical fiber path 105S can easily become uniform circumferentially.

[0084] The upstream branch passage 174 has a flow path 171a as an inlet and two flow paths 171b as outlets. The cross-sectional area of ​​each flow path 171b is half that of flow path 171a. Similarly, the downstream branch passage 175 has a flow path 171b as an inlet and two flow paths 171c as an outlet. The cross-sectional area of ​​each flow path 171c is half that of flow path 171b. Furthermore, the cross-sectional area of ​​the inlet of each branch passage is equal to the sum of the cross-sectional areas of their respective outlets. In this structure, the second resin 15 can be evenly branched through each branch passage.

[0085] The second flow path 171 includes four outlets, namely flow paths 171c, branching out through the upstream branch path 174 and the downstream branch path 175. The four flow paths 171c are evenly arranged circumferentially with the optical fiber path 105S as the center. With this structure, the flow of the second resin 15 near the optical fiber path 105S can easily become uniform circumferentially.

[0086] This invention is not limited to the embodiments described above, and appropriate changes can be made without departing from the spirit of the claims.

[0087] For example, an example of insulation layer 191 being formed of air is shown, but insulation layer 191 may also be formed of insulation material or the like.

[0088] Additionally, an example is shown where the heat source of the first temperature regulator 160 is a heater 162 arranged along the first flow path 151. However, the heat source of the first temperature regulator 160 can also replace the heater 162, and instead be a flow path arranged along the first flow path 151. This flow path can have the same structure as the temperature-regulating water flow path 182, and can also supply warm water that is managed to reach a different temperature than the warm water supplied to the temperature-regulating water flow path 182. Furthermore, the heat source of the second temperature regulator 180 can also replace the temperature-regulating water flow path 182, and instead be a heater identical to the heater 162.

[0089] Examples of flow paths with two branches are shown in upstream branch paths 154 and 174 and downstream branch paths 155 and 175, but the structure of each branch path is not limited to this. For example, a branch path may also have more than three outlets relative to a single inlet. Additionally, flow paths 151 and 171 may only have upstream flow paths. In this case, the branch path may have more than three outlets relative to a single inlet.

Claims

1. A coating apparatus comprising: The optical fiber path allows the glass fiber to pass vertically downwards; The first flow path is a flow path that allows the first resin to flow toward the optical fiber passage, and has a first branch path that allows the first resin, which moves in the horizontal direction, to branch horizontally. A first temperature regulator, which is configured along the first flow path, performs temperature regulation of the first flow path; The second flow path, which is a flow path that allows the second resin to flow toward the optical fiber passage, has a second branch path that branches the second resin moving in the horizontal direction horizontally, and is located lower than the first flow path; and A second temperature regulator, configured along the second flow path, adjusts the temperature of the second flow path. The first flow path and the first temperature regulator form a first annular body, which has a ring shape arranged with the optical fiber path as the center. The second flow path and the second temperature regulator form a second annular body, which has a ring shape disposed below the first annular body with the optical fiber path as the center. After the first flow path and the second flow path each branch into two, they further branch into two more from a position 90° forward along the circumference of the optical fiber path, thus becoming a flow path with four branches. The four flow paths with four branches are spaced 90° apart from each other along the circumference.

2. The coating apparatus according to claim 1, wherein, The first annular body and the second annular body are separated in the vertical direction, and a heat insulation layer composed of an air layer is formed between the first annular body and the second annular body.

3. The coating apparatus according to claim 1 or 2, wherein, The first flow path and the second flow path are located vertically between the first temperature regulator and the second temperature regulator. The first flow path adjusts the temperature through the first temperature regulator, and the second flow path adjusts the temperature through the second temperature regulator.

4. The coating apparatus according to claim 1 or 2, wherein, The heat source of the first temperature regulator is a heater arranged along the first flow path. The heat source of the second temperature regulator is a third flow path configured along the second flow path to allow the fluid after temperature adjustment to flow.

5. A coating method for applying resin to glass fibers, The application method comprises the following steps: The glass fiber passes through the optical fiber path in a vertically downward direction; The first resin is allowed to flow through the first horizontally branched flow path, and the temperature is adjusted by the first temperature regulator, thereby adjusting the temperature of the first resin to the first temperature. The second resin is allowed to flow through a second flow path that branches horizontally and is located below the first flow path. The temperature is adjusted by a second temperature regulator, thereby adjusting the temperature of the second resin to a second temperature. The glass fiber moving within the optical fiber path is coated with the first resin flowing through the first flow path; and The glass fiber coated with the first resin moves within the optical fiber path and is coated with the second resin flowing through the second flow path. The first flow path and the first temperature regulator form a first annular body, which has a ring shape arranged with the optical fiber path as the center. The second flow path and the second temperature regulator form a second annular body, which has a ring shape disposed below the first annular body with the optical fiber path as the center. After the first flow path and the second flow path each branch into two, they further branch into two more from a position 90° forward along the circumference of the optical fiber path, thus becoming a flow path with four branches. The four flow paths with four branches are spaced 90° apart from each other along the circumference.

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