Sealing device

Abstract

To provide a sealing device capable of suppressing intrusion of outside air into a furnace.SOLUTION: A sealing device 1 comprises a blade housing body 30, a first blade 10 and a plurality of second blades 20, the first blade 10 having a first body part 11 and a pair of first side parts 12, the second blades 20 each having a second body part 21 and a pair of second side parts 22, and the blade housing body 30 having a plurality of first housing parts 31, a plurality of second housing parts 32, and a partition wall 33, the partition wall 33 having a low back part 332 and a high back part 331, and lower surfaces 12L of the first side parts 12 covering an entire space SP formed by a side surface 11S of the first body part 11, side surfaces 22S of the second side parts 22, and a top on a center 30C side of the low back part 332.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a sealing device. [Background technology]

[0002] An optical fiber is manufactured by drawing an optical fiber preform. An optical fiber drawing furnace for drawing an optical fiber preform includes a furnace in which the optical fiber preform is housed, and the furnace is filled with an inert gas or other furnace gas. For this reason, a sealing device is sometimes used to close the upper opening of the drawing furnace for housing the optical fiber preform in the furnace.

[0003] Such a sealing device is described in the following Patent Document 1. This sealing device includes an annular plate having an opening through which an optical fiber preform can be inserted, and a plurality of long blades that can move in the radial direction of the opening and have ends that can abut against the side surfaces of the optical fiber preform. The plate is provided with a housing section that houses a part of each blade, and the housing section is partitioned by a pair of long partition walls. The width of each housing section in a direction perpendicular to the longitudinal direction of the partition walls is approximately constant in the radial direction, and the width of each partition wall in a direction perpendicular to the radial direction of the opening narrows from a position away from the opening toward the opening. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-13135 A Summary of the Invention [Problem to be solved by the invention]

[0005] In such a sealing device, a space may be formed between adjacent blades and the top of the partition wall on the opening side. When such a space is formed, there is a concern that outside air may enter the furnace through the space.

[0006] Therefore, an object of the present invention is to provide a sealing device capable of preventing outside air from entering a furnace. [Means for solving the problem]

[0007] In order to achieve the above object, a first aspect of the present invention is a sealing device comprising: a blade case having an opening into which an optical fiber preform can be inserted and a main surface extending outside the opening; and a plurality of first blades and a plurality of second blades arranged alternately along a circumferential direction of the opening and movable in a radial direction of the opening along the main surface, the sealing device being configured to seal a gap between the optical fiber preform and the upper opening by contacting the optical fiber preform inserted from an upper opening of an optical fiber drawing furnace through the opening with each of the first blades and each of the second blades, the first blades having a first body portion including a first body intermediate portion and a first body outer portion provided on an outer edge side of the blade case relative to the first body intermediate portion, and a pair of first side portions protruding from the first body portion in the circumferential direction of the first body portion, the second blade having a second body portion including a second body inner portion and a second body outer portion provided on an outer edge side of the blade case relative to the second body inner portion, and a pair of second side portions protruding from the second main body portion in the circumferential direction of the main body portion, the blade housing having a plurality of first housing portions arranged along the circumferential direction and capable of housing the first main body outer portion, a plurality of second housing portions arranged alternately with the first housing portions along the circumferential direction and capable of housing the second main body outer portion, and a partition wall separating the first housing portion and the second housing portion adjacent to each other, the partition wall having a high back portion and a pair of second side portions protruding from the high back portion in the radial direction of the partition wall and extending from the main surface. and a low-back portion having a height lower than that of the high-back portion, wherein the underside of the first side portion facing the main surface is positioned at a position equal to or higher than the height of the upper surface of the low-back portion from the main surface and lower than the height of the upper surface of the high-back portion from the main surface, and the underside of the first side portion covers the entire space formed by the side of the first main body portion facing in the circumferential direction, the side of the second side portion adjacent to the side, and the top of the low-back portion on the center side of the opening.

[0008] According to this sealing device, the underside of the first side portion covers the entire space formed by the side surface of the first main body portion facing in the circumferential direction, the side surface of the second side portion adjacent to said side surface, and the top of the low-back portion on the center side of the opening, thereby making it possible to prevent outside air from entering the optical fiber drawing furnace through said space. Effect of the Invention

[0009] According to the present invention, a sealing device capable of suppressing the intrusion of outside air into a furnace is provided. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of an optical fiber drawing furnace according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing an outline of the sealing device of FIG. [Diagram 3] FIG. 3 is a perspective view showing a portion of the sealing device of FIG. 2. [Figure 4] FIG. 4 is a perspective view showing a part of the blade container; [Diagram 5] FIG. 2 is a perspective view of a first blade showing its underside. [Figure 6] FIG. 2 is a perspective view of a first blade showing its top surface. [Figure 7] FIG. 1 is a perspective view of a second blade showing its top surface. [Figure 8] FIG. 13 is a perspective view of a second blade showing its underside. [Figure 9] FIG. 2 is a diagram showing a state in which a first blade and a second blade are arranged in a blade container. [Figure 10] 2 is a view of a first blade and a second blade arranged in a blade housing, as viewed from the main surface side of the housing. FIG. [Figure 11] 4 is an enlarged view showing a portion of a first blade and a second blade arranged in a blade container. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The sealing device according to the present invention will be illustrated below with reference to the accompanying drawings. The embodiments illustrated below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved within the scope of the claims without departing from the spirit of the present invention. In the drawings referred to below, the dimensions of each component may be changed to facilitate understanding.

[0012] Fig. 1 is a schematic diagram of an optical fiber drawing furnace according to an embodiment of the present invention. As shown in Fig. 1, the optical fiber drawing furnace 100 of this embodiment is a furnace that draws an optical fiber preform 200 to form an optical fiber 210, and mainly comprises a furnace tube 101, a heater 102, a heat insulating material 103, a housing 104, and a sealing device 1. The sealing device 1 of this embodiment is a sealing device for an optical fiber drawing furnace.

[0013] Although not shown, the optical fiber preform 200 is configured by surrounding the outer peripheral surface of a rod-shaped core glass body that becomes at least one core with a cladding glass body. The optical fiber preform 200 may include components other than the core glass body and the cladding glass body. A glass rod 220 for suspending the optical fiber preform 200 is connected to the upper part of the optical fiber preform 200.

[0014] The core tube 101 is a cylindrical member extending in the height direction of the optical fiber drawing furnace 100, and is capable of accommodating the optical fiber preform 200 in an internal space 101S. The inner and outer diameters of the core tube 101 are approximately constant in the extension direction of the core tube 101. The core tube 101 is made of, for example, quartz, carbon, or the like.

[0015] The heater 102 is a cylindrical heating element formed to surround the outer circumferential surface of the furnace core tube 101. An example of the heater 102 is a heater made of carbon. The heat insulating material 103 is configured to surround the heater 102 and the outer circumferential surface of the furnace core tube 101. The heat insulating material 103 is made of, for example, porous ceramic.

[0016] The housing 104 has a cylindrical peripheral wall that extends in the height direction of the optical fiber drawing furnace 100 and surrounds the outer circumferential surface of the thermal insulation material 103, and upper and lower walls that are connected to the upper and lower ends of the peripheral wall, sandwich the thermal insulation material 103 from above and below, and close the gap between the peripheral wall and the furnace core tube. The housing 104 may have a cooling function such as water cooling.

[0017] A lower housing 105 is provided below the furnace core tube 101. The upper part of the lower housing 105 is open so as to be connected to the internal space 101S of the furnace core tube 101, and the lower part is open so that the drawn optical fiber 210 can be led out.

[0018] The inner space 101S of the furnace tube 101 contains He, Ne, Ar, N 2 The inert gas may be filled with a mixed gas in which another gas is added to the inert gas.

[0019] The upper part of the furnace tube 101 is open, and a sealing device 1 is disposed on the upper part of the furnace tube 101 and the housing 104. The sealing device 1 is a device for sealing the upper opening 100H of the optical fiber drawing furnace 100 together with the optical fiber preform 200 inserted from the upper opening 100H. Note that the upper part of the optical fiber preform 200 may be surrounded by a cover body 110 as shown in FIG.

[0020] Next, the sealing device 1 will be described.

[0021] Fig. 2 is a plan view showing an outline of the sealing device 1, and Fig. 3 is a perspective view showing a part of the sealing device 1 of Fig. 2. As shown in Fig. 2 and Fig. 3, the sealing device 1 of the present embodiment includes a plurality of blades including a plurality of first blades 10 and a plurality of second blades 20, and a blade holder 30. The blade holder 30 has an opening 30H indicated by a dashed line through which the optical fiber preform 200 can be inserted.

[0022] Each of the first blades 10 and each of the second blades 20 has a shape in which the longitudinal direction extends in the radial direction of the opening 30H. Each of the first blades 10 and each of the second blades 20 are alternately arranged radially along the circumferential direction of the opening 30H. The blade housing 30 has a generally ring-like shape and has a first housing section 31 in which the first blade 10 is housed and a second housing section 32 in which the second blade 20 is housed. Note that FIG. 2 illustrates the blade housing 30 with the top cover removed, so that the first housing section 31 and the second housing section 32 can be seen, but FIG. 3 illustrates the blade housing 30 with the top cover not removed, so that the first housing section 31 and the second housing section 32 cannot be seen.

[0023] Each of the first blade 10 and the second blade 20 is configured to be movable in the radial direction of the opening 30H by a blade moving mechanism such as a shaft spring or an air cylinder (not shown), and is biased toward the center 30C of the opening 30H by a biasing means such as a spring (not shown). FIG. 2 shows a state in which each of the first blade 10 and the second blade 20 protrudes inside the opening 30H, and FIG. 3 shows a state in which each of the first blade 10 and the second blade 20 moves outside the opening 30H of the blade housing 30 and is housed in the blade housing 30. As shown in FIG. 2, an opening 1H having a smaller diameter than the opening 30H is formed by being surrounded by inner tip portions 10I and 20I, which are ends of the first blade 10 and the second blade 20 on the center 30C side of the opening 30H. The first blade 10 and the second blade 20 can abut against a side surface 201 of the optical fiber preform 200 inserted into the opening 1H. 2 and 3, the inner tip portions 10I, 20I which are ends forming the opening 1H of the first blade 10 and the second blade 20 are curved along the circumferential direction with a predetermined radius of curvature, and the generation of a gap between the inner tip portions 10I, 20I and the optical fiber preform 200 is suppressed. The first blade 10 and the second blade 20 will be described in detail later.

[0024] Next, the blade container 30 will be described.

[0025] FIG. 4 is a perspective view showing a part of the blade housing 30. Note that FIG. 4 shows the blade housing 30 cut in half. As shown in FIG. 4, the blade housing 30 includes a plate 35 having a planar main surface 30S that is approximately perpendicular to the opening direction of the opening 30H and extends outside the opening 30H. In this embodiment, when the plate 35 is viewed from the front, an outer edge 351 of the plate 35 is approximately circular. The outer edge 351 is also the outer edge of the blade housing 30. For this reason, in the following description, the outer edge 351 may refer to the outer edge of the blade housing 30. Note that the outer edge 351 is not limited to a circle, and may be polygonal. On the main surface 30S, the first housing sections 31, the number of which is the same as the number of first blades 10, are provided at a certain distance outward from the opening 30H so as to be aligned along the circumferential direction of the opening 30H. In addition, second housing sections 32, the number of which is equal to the number of second blades 20, are provided alternately with the first housing sections 31 along the circumferential direction of the opening 30H at a certain distance outward from the opening 30H. Each of the first housing sections 31 and each of the second housing sections 32 are provided on the main surface 30S, and their longitudinal directions extend radially along the radial direction of the opening 30H. The widths of the first housing section 31 and the second housing section 32 in a direction perpendicular to the longitudinal direction of the first housing section 31 and the second housing section 32 and parallel to the main surface 30S are constant. The first housing section 31 and the second housing section 32 adjacent to each other are separated by a partition wall 33 provided on the main surface 30S. In addition, the direction perpendicular to the longitudinal direction of the first storage section 31 and the second storage section 32 refers to the direction perpendicular to the longitudinal direction of the focused first storage section 31 and focused second storage section 32 when focusing on one first storage section 31 and one second storage section 32.

[0026] The partition 33 has a generally isosceles triangular shape when the blade housing 30 is viewed from above, and is disposed so that the equilateral sides approach each other from the outer edge 351 of the plate 35 toward the center 30C of the opening 30H. Therefore, a pair of side surfaces 33S of the partition 33 facing approximately in the circumferential direction of the opening 30H approach each other from the outer edge 351 of the plate 35 toward the center C. Since the widths of the first housing section 31 and the second housing section 32 are constant as described above, the side surfaces 33S are generally planar.

[0027] The partition wall 33 has a high back portion 331 and a low back portion 332 that protrudes from the high back portion 331 in the radial direction of the partition wall 33, has a height from the main surface 30S lower than that of the high back portion 331, and includes a radially inner apex of the opening 30H in the partition wall 33. The high back portion 331 is higher than the low back portion 332 based on the main surface 30S. Therefore, the upper surface 331T on the opposite side to the main surface 30S side of the high back portion 331 is farther from the main surface 30S than the upper surface 332T on the opposite side to the main surface 30S side of the low back portion 332. An end surface 331I facing the center 30C side is formed between the upper surfaces 331T and 332T. In this embodiment, the end surface 331I is approximately perpendicular to the main surface 30S and is approximately planar. Therefore, the shape of the upper surface 331T is approximately trapezoidal. In addition, the apex of the partition 33 on the center 30C side, i.e., the apex of the low back portion 332 on the center 30C side, is not sharp, and an end face 332I facing the center 30C side is formed. In this embodiment, the end face 332I is substantially perpendicular to the main surface 30S and is substantially flat. Therefore, the upper surface 332T is substantially trapezoidal.

[0028] A frame portion 34 is provided on the outer edge 351 side of the partition wall 33, and the partition wall 33 is formed continuously with the frame portion 34. Therefore, an inner wall 341 of the frame portion 34 faces the first storage portion 31 and the second storage portion 32.

[0029] Next, the first blade 10 will be described.

[0030] Fig. 5 is a perspective view of the first blade 10 showing the underside 10L on the main surface 30S side of the blade container 30, and Fig. 6 is a perspective view of the first blade 10 showing the top surface 10T on the side opposite to the main surface 30S side. As shown in Figs. 5 and 6, the first blade 10 has a first main body portion 11 and a pair of first side portions 12.

[0031] The first body portion 11 has a first body outer portion 111, a first body intermediate portion 112, and a first body inner portion 113. The first body outer portion 111 is a portion including an end portion of the first body portion 11 on the outer edge 351 side. A pair of side surfaces 111S of the first body outer portion 111 facing in the circumferential direction of the opening 30H are flat and generally parallel to each other. A chamfer is formed between the side surface 111S of the first body outer portion 111 and the end surface 11O of the first body portion 11 facing the outer edge 351 side. Since the first main body outer part 111 is accommodated in the first accommodation section 31, the distance between the side surfaces 33S of the pair of partition walls 33 that sandwich the first accommodation section 31 is equal to or greater than the width of the first main body outer part 111 in a direction perpendicular to the movement direction of the first blade 10 and parallel to the main surface 30S, and in this embodiment, the distance between the pair of side surfaces 111S is slightly smaller than the distance between the side surfaces 33S of the pair of partition walls 33 that sandwich the first accommodation section 31. Note that the direction perpendicular to the movement direction of the first blade 10 refers to the direction perpendicular to the movement direction of the focused first blade 10 when focusing on one first blade 10.

[0032] The first body intermediate portion 112 is located closer to the center 30C than the first body outer portion 111 and is continuous with the first body outer portion 111. Therefore, the first body outer portion 111 is provided closer to the outer edge 351 of the blade container 30 than the first body intermediate portion 112. A pair of side surfaces 112S of the first body intermediate portion 112 facing the circumferential direction of the opening 30H are each formed continuously with the side surfaces 111S of the first body outer portion 111. The distance between the pair of side surfaces 112S becomes smaller from the outer edge 351 side toward the center 30C side. Therefore, the width of the first body intermediate portion 112 in a direction perpendicular to the moving direction of the first blade 10 and parallel to the main surface 30S becomes smaller from the outer edge 351 side toward the center 30C side.

[0033] The first body inner part 113 is located closer to the center 30C than the first body intermediate part 112, and is continuous with the first body intermediate part 112. The distance between a pair of side surfaces 113S of the first body inner part 113 facing the circumferential direction of the opening 30H becomes smaller from the outer edge 351 side toward the center 30C side. Therefore, the width of the first body inner part 113 in a direction perpendicular to the moving direction of the first blade 10 and parallel to the main surface 30S becomes smaller from the outer edge 351 side toward the center 30C side. In addition, the above-mentioned width of the first body inner part 113 is smaller than the width of the first body intermediate part 112. In other words, the width of the first body inner part 113 on the outer edge 351 side is smaller than the width of the first body intermediate part 112 on the center 30C side. Therefore, there is a step extending from the side surface 112S of the first main body intermediate portion 112 toward the side surface 113S of the first main body inner portion 113 into the inside of the first main body portion 11, and the substantially planar side surface 112I is located at the step. The side surface 112I faces the opening 30H.

[0034] The lower surface 11L, which is the surface on the main surface 30S side of the first main body portion 11, is generally flat. Therefore, the lower surfaces of the first main body outer portion 111, the first main body middle portion 112, and the first main body inner portion 113 are generally flush with each other.

[0035] The first side portions 12 protrude from the first main body portion 11 in the circumferential direction of the first main body portion 11. Each of the first side portions 12 is formed continuously on the first main body portion 11 on the side 11S of the first main body portion 11 opposite the main surface 30S side. In this embodiment, the upper surface 11T of the first main body portion 11 opposite the main surface 30S side and the upper surface 12T of the first side portion 12 opposite the main surface 30S side are generally flush with each other. Therefore, the upper surface 10T of the first blade 10 is generally flat. The thickness of the first side portion 12 in a direction perpendicular to the main surface 30S is smaller than the thickness of the first main body portion 11 in the direction. Therefore, the lower surface 12L of the first side portion 12 is farther from the main surface 30S than the lower surface 11L of the first main body portion 11. The lower surface 11L of the first main body portion 11 and the lower surfaces 12L of the first side portions 12 form the lower surface 10L of the first blade 10.

[0036] Each of the first side portions 12 extends from the middle of the first outer body portion 111 to the end of the first inner body portion 113 on the center 30C side in the moving direction of the first blade 10. The first side portion 12 is formed continuously with the first outer body portion 111 and has an end face 12O facing the outer edge 351 side. In addition, the side face 12S of each of the first side portions 12 facing the circumferential direction of the opening 30H is flat. The distance between the side faces 12S of each of the first side portions 12 becomes smaller from the outer edge 351 side toward the center 30C side. In other words, in a direction perpendicular to the moving direction of the first blade 10 and parallel to the main surface 30S, the width of the portion of the first blade 10 where the first side portion 12 is formed becomes smaller from the outer edge 351 side toward the center 30C side. Further, on the outer edge 351 side of the first side portion 12, the distance between one side surface 12S and the other side surface 12S of the first side portion 12 is greater than the distance between the side surfaces 33S of a pair of partition walls 33 that sandwich the first storage portion 31. Therefore, the first side portion 12 is not stored in the first storage portion 31.

[0037] The first main body 11 has a shape in which the edge on the tip side of the lower surface 11L is chamfered. That is, the first blade 10 has a lower curved surface 10LC in which the direction of inclination gradually approaches the height direction of the blade 10 from the lower surface 11L closest to the main surface 30S to the inner tip portion 10I so that the thickness of the first blade 10 becomes smaller. This height direction is a direction perpendicular to the main surface 30S. Also, the first blade 10 has a shape in which the edge on the tip side of the upper surface 10T is chamfered. That is, the first blade 10 has an upper curved surface 10TC in which the direction of inclination gradually approaches the height direction of the blade 10 from the upper surface 10T on the opposite side to the main surface 30S side to the inner tip portion 10I so that the thickness of the first blade 10 becomes smaller. In this embodiment, the lower curved surface 10LC is a part of a torus surface, and the upper curved surface 10TC is a part of a torus surface different from the torus surface of the lower curved surface 10LC. The inner tip portion 10I is located between the lower curved surface 10LC and the upper curved surface 10TC, and extends a predetermined distance in the up-down direction.

[0038] Next, the second blade 20 will be described.

[0039] Fig. 7 is a perspective view of the second blade 20 showing the upper surface 20T opposite to the main surface 30S of the blade container 30, and Fig. 8 is a perspective view of the second blade 20 showing the lower surface 20L on the main surface 30S side. As shown in Figs. 7 and 8, the second blade 20 has a second main body portion 21 and a pair of second side portions 22.

[0040] The second main body portion 21 has a second main body outer portion 211 and a second main body inner portion 212. The second main body outer portion 211 is a portion including an end portion of the second main body portion 21 on the outer edge 351 side. A pair of side surfaces 211S of the second main body outer portion 211 facing in the circumferential direction of the opening 30H are flat and generally parallel to each other. A chamfer is formed between the side surface 211S of the second main body outer portion 211 and the end surface 21O of the second main body portion 21 facing the outer edge 351 side. Since the second main body outer part 211 is accommodated in the second accommodation section 32, the distance between the pair of partition walls 33 sandwiching the second accommodation section 32 is equal to or greater than the width of the second main body outer part 211 in a direction perpendicular to the movement direction of the second blade 20 and parallel to the main surface 30S, and in this embodiment, the distance between the pair of side surfaces 211S is slightly smaller than the distance between the side surfaces 33S of the pair of partition walls 33 sandwiching the second accommodation section 32. Note that the direction perpendicular to the movement direction of the second blade 20 refers to the direction perpendicular to the movement direction of the focused second blade 20 when focusing on one second blade 20.

[0041] The second main body inner part 212 is located closer to the center 30C than the second main body outer part 211 and is continuous with the second main body outer part 211. Therefore, the second main body outer part 211 is provided closer to the outer edge 351 side of the blade container 30 than the second main body inner part 212. The distance between a pair of side surfaces 212S of the second main body inner part 212 facing the circumferential direction of the opening 30H becomes smaller from the outer edge 351 side toward the center 30C side. Therefore, the width of the second main body inner part 212 in a direction perpendicular to the moving direction of the second blade 20 and parallel to the main surface 30S becomes smaller from the outer edge 351 side toward the center 30C side. In addition, the width of the second main body inner part 212 on the outer edge 351 side is smaller than the width of the second main body outer part 211. Therefore, there is a step extending from the side surface 211S of the second main body outer portion 211 toward the side surface 212S of the second main body inner portion 212 into the inside of the second main body portion 21, and a substantially planar end surface 211I is located at the step. The end surface 211I faces the opening 30H.

[0042] The upper surface 21T of the second main body portion 21 is generally flat. Therefore, the upper surface of the second main body outer portion 211 and the upper surface of the second main body inner portion 212 are generally flush with each other.

[0043] The second side portions 22 protrude from the second main body portion 21 in the circumferential direction of the second main body portion 21. Each of the second side portions 22 is formed continuously on the second main body portion 21 on the main surface 30S side of the side surface 21S of the second main body portion 21. In this embodiment, the lower surface 21L on the main surface 30S side of the second main body portion 21 and the lower surface 22L on the main surface 30S side of the second side portion 22 are generally flush and planar. Therefore, the lower surface 20L of the second blade 20 is generally planar. The thickness of the second side portion 22 in a direction perpendicular to the main surface 30S is smaller than the thickness of the second main body portion 21 in the same direction. Therefore, the upper surface 22T of the second side portion 22 is located closer to the main surface 30S than the upper surface 21T of the second main body portion 21. An upper surface 20T of the second blade 20 is formed by an upper surface 21T of the second main body portion 21 and an upper surface 22T of each of the second side portions 22.

[0044] Each second side portion 22 is provided on the second main body inner portion 212, and is not provided on the side surface 211S of the second main body outer portion 211. Each second side portion 22 is formed continuously on the end surface 211I of the second main body outer portion 211, and extends to the end portion on the center 30C side of the second main body inner portion 212. The second side portion 22 has a second outer side portion 221 and a second inner side portion 222.

[0045] The second lateral outer portion 221 is a portion on the outer edge 351 side of the second lateral portion 22, and is formed continuously with the second main body outer portion 211. The side surfaces 221S of the second lateral outer portion 221 facing the circumferential direction of the opening 30H are planar and generally parallel to each other. In addition, each side surface 221S is flush with the side surface 211S of the second main body outer portion 211. Therefore, the distance between the side surfaces 33S of the pair of partition walls 33 sandwiching the second storage portion 32 is equal to or greater than the distance between the side surfaces 221S, and in this embodiment, the distance between the pair of side surfaces 211S is slightly smaller than the distance between the side surfaces 33S. Therefore, at least a portion of the second lateral outer portion 221 is accommodated in the second storage portion 32. In addition, each planar side surface 211S is shaped to follow the side surface 33S.

[0046] The second lateral inner portion 222 is located closer to the center 30C than the second lateral outer portion 221, and is continuous with the second lateral outer portion 221. The distance between the side surfaces 222S of the second lateral inner portions 222 facing the circumferential direction of the opening 30H becomes smaller from the outer edge 351 side toward the center 30C side. The distance between the side surfaces 222S on the outer edge 351 side is larger than the distance between the side surfaces 211S of the second lateral outer portion 221. Therefore, there is a step protruding from the side surface 211S toward the side surface 222S toward the side surface 222S opposite to the second main body portion 21 side, and the substantially planar side surface 222O is located at the step. The side surface 222O faces the outer edge 352 side. In addition, any one of the side surfaces 222S of the second circumferentially facing lateral inner portion 222 may be located closer to the first blade 10 adjacent to the second circumferentially facing lateral outer portion 221 than the side surface 221S of the second circumferentially facing lateral outer portion 221.

[0047] The second main body 21 has a shape in which the edge on the tip side of the lower surface 22L on the main surface 30S side is chamfered. That is, the second blade 20 has a lower curved surface 20LC in which the direction of inclination gradually approaches the height direction of the second blade 20 from the lower surface 22L to the inner tip 20I so that the thickness of the second blade 20 becomes smaller. This height direction is a direction perpendicular to the main surface 30S. Also, the second blade 20 has a shape in which the edge on the tip side of the upper surface 21T farthest from the main surface 30S side is chamfered. That is, the second blade 20 has an upper curved surface 20TC in which the direction of inclination gradually approaches the height direction of the second blade 20 so that the thickness of the second blade 20 becomes smaller from the upper surface 21T farthest from the main surface 30S side to the inner tip 20I. In this embodiment, the lower curved surface 20LC is a part of a torus surface, and the upper curved surface 20TC is a part of a torus surface different from the torus surface of the lower curved surface 20LC. The inner tip portion 20I is located between the lower curved surface 20LC and the upper curved surface 20TC, and extends a predetermined distance in the up-down direction.

[0048] Next, a state in which first blade 10 and second blade 20 are arranged in blade container 30 will be described.

[0049] Fig. 9 is a diagram showing a state in which the first blade 10 and the second blade 20 are arranged in the blade container 30. For ease of viewing, Fig. 9 shows a state in which one first blade 10 and one second blade 20 are arranged. Note that the frame portion 34 is omitted in Fig. 9.

[0050] 9, the first blade 10 is disposed in the blade housing 30 with the underside 10L facing the main surface 30S, and the second blade 20 is disposed in the blade housing 30 with the underside 20L facing the main surface 30S. When the first blade 10 and the second blade 20 are disposed adjacent to each other, the second lateral portion 22 of the second blade 20 is located between the main surface 30S and the underside 12L of the first lateral portion 12 of the first blade 10.

[0051] Further, the lower surface 12L of the first side portion 12 of the first blade 10 is disposed at a position equal to or higher than the height of the upper surface 332T of the low back portion 332 and lower than the upper surface 333T of the high back portion 333. In this embodiment, the lower surface 12L is disposed at a position higher than the height of the upper surface 332T of the low back portion 332. Therefore, the first side portion 12 of the first blade 10 covers at least a part of the low back portion 332 of the partition wall 33, and the lower surface 12L of the first side portion 12 and the upper surface 332T of the low back portion 332 face each other. Therefore, the end surface 12O of the first side portion 12 facing the outer edge 351 side is positioned in a direction facing the end surface 331I of the partition wall 33. Therefore, when the first blade 10 moves toward the outer edge 351, the movement of the first side portion 12 in that direction is blocked by the high back portion 331 of the partition wall 33, preventing the first blade 10 from moving too far away from the opening 30H.

[0052] The width of the end face 331I in a direction perpendicular to the direction from the center 30C side toward the outer edge 351 side of the partition wall 33 and parallel to the main surface 30S may be smaller than the width in that direction of the end face 12O of the first side portion 12. In this case, a part of the first side portion 12 may extend to the second storage portion.

[0053] Furthermore, side surface 222O of second lateral portion 22 facing outer edge 351 of second blade 20 is located in the direction facing end surface 332I of the apex of low back portion 332. Therefore, when second blade 20 moves toward outer edge 351, movement of second lateral portion 22 in that direction is blocked by low back portion 332 of partition wall 33, and second blade 20 is prevented from moving too far away from opening 30H.

[0054] FIG. 10 is a view of the first blade 10 and the second blade 20 arranged in the blade housing 30, viewed from the main surface 30S side of the blade housing 30. As shown in FIG. 10, the side surface 112S of the first main body intermediate portion 112 of the first blade 10 faces the side surface 221S of the second lateral outer portion 221 of the second blade 20, and the side surface 113S of the first main body inner portion 113 of the first blade 10 faces the side surface 222S of the second lateral inner portion 222 of the second blade 20. In the state of FIG. 10, the side surface 112I of the first main body inner portion 113 of the first blade 10 faces the side surface 222O of the second lateral inner portion 222 of the second blade 20. In this embodiment, the side surface 112S and the side surface 221S are parallel to each other, the side surface 113S and the side surface 222S are parallel to each other, and the side surface 112I and the side surface 222O are parallel to each other. Also, the length of the side surface 112S along the main surface 30S is shorter than the length of the side surface 221S along the main surface 30S, but the length of the side surface 113S along the main surface 30S is approximately equal to the length of the side surface 223S along the main surface 30S, and the length of the side surface 112I along the main surface 30S is approximately equal to the length of the side surface 222O along the main surface 30S. Therefore, the shape of the side surface 11S of the first main body portion 11 and the shape of the side surface 22S of the second lateral portion 22 are approximately complementary to each other. There is a slight gap between the side surface 112S and the side surface 221S, and between the side surface 113S and the side surface 222S. It is preferable that this gap is formed even when the first blade 10 and the second blade 20 move most toward the center 30C of the opening 30H as shown in FIG. 2 and the first blade 10 and the second blade 20 are closest to each other. Furthermore, in a state in which first blade 10 and second blade 20 have moved furthest toward center 30C of opening 30H, it is preferable that a part of side surface 112I of first main body portion of first blade 10 faces a part of side surface 222O of second lateral portion 22 of second blade 20. In this case, the above-mentioned gaps formed between side surface 112S and side surface 221S, and between side surface 113S and side surface 222S can be made smaller than when side surface 112I and side surface 222O do not face each other.

[0055] FIG. 11 is an enlarged view showing a part of the first blade 10 and the second blade 20 disposed in the blade housing 30. As described above, the first side portion 12 of the first blade 10 covers at least a part of the lower back portion 332, and further covers at least a part of the second side portion 22 of the second blade 20. Therefore, the lower surface 12L of the first side portion 12 covers the entire space SP formed by the side surface 11S of the first main body portion 11, the side surface 22S of the second side portion 22, and the top portion on the center 30C side of the lower back portion 332.

[0056] Also, as shown in FIG. 11, the end surface 12O of the first side portion 12 facing the outer edge 351 side in the first blade 10 and the end surface 211I of the second blade 20 facing the center 30C side of the second main body outer portion 211 face each other. As shown in FIG. 11, it is preferable that a gap is formed between the end surface 12O and the end surface 211I.

[0057] Next, the operation of the sealing device 1 will be described.

[0058] When the optical fiber base material 200 is inserted from the upper opening 100H of the optical fiber drawing furnace 100 through the opening 30H of the blade housing 30, the first blade 10 is housed in the first housing portion 31 and the second blade 20 is housed in the second housing portion 32 so that the diameter of the opening 1H formed by the inner tip portion 10I of the first blade 10 and the inner tip portion 20I of the second blade 20 is substantially the same as the diameter of the optical fiber base material 200. The optical fiber base material 200 is inserted into the internal space 101S of the optical fiber drawing furnace 100 through the opening 1H in a state where the inner tip portion 10I of the first blade 10 and the inner tip portion 20I of the second blade 20 are in contact with the side surface 201 of the optical fiber base material 200. Then, with the optical fiber base material 200 set in the optical fiber drawing furnace 100, the heater 102 is heated to draw the optical fiber 210 from the optical fiber base material 200.

[0059] At this time, the internal space 101S is filled with the inert gas as described above, and the outside is the atmosphere. However, since the first side portion 12 of the first blade 10 and the second side portion 22 of the second blade 20 overlap, the atmosphere is prevented from entering the space 101. Furthermore, since the lower surface 12L of the first side portion 12 of the first blade 10 covers the entire space SP, the atmosphere is prevented from entering the internal space 101S through the space SP.

[0060] From the above description, the following aspects are derived as part of the present invention.

[0061] That is, the first aspect of the present invention includes a blade container 30 having an opening 30H into which an optical fiber preform 200 can be inserted and a main surface 30S extending outside the opening 30H, and a plurality of first blades 10 and a plurality of second blades 20 arranged alternately along the circumferential direction of the opening 30H and movable in the radial direction of the opening 30H along the main surface 30S, and the first blades 10 and the second blades 20 come into contact with the optical fiber preform 200 inserted from the upper opening 100H of the optical fiber drawing furnace 100 via the opening 30H, thereby forming an optical fiber preform The sealing device 1 is for sealing a gap between the upper opening 100H and the first blade 10, the first blade 10 having a first body portion 11 including a first body intermediate portion and a first body outer portion 111 provided on the outer edge 351 side of the blade container 30 relative to the first body intermediate portion 112, and a pair of first lateral portions 12 protruding from the first body portion 11 in the circumferential direction of the first body portion 11, the second blade 20 having a second body portion 21 including a second body inner portion 212 and a second body outer portion 211 provided on the outer edge 351 side of the blade container 30 relative to the second body inner portion 212, and a pair of second side portions 22 protruding from the second main body portion 12 in the circumferential direction of the second main body portion 21. The blade housing 30 has a plurality of first housing portions 31 arranged along the circumferential direction and capable of housing the first main body outer portion 111, a plurality of second housing portions 32 arranged alternately with the first housing portions 31 along the circumferential direction and capable of housing the second main body outer portion 211, and a partition wall 33 separating the adjacent first housing portions 31 and second housing portions 32, the partition wall 33 having a high back portion 331 and a height from the main surface 30S of the high back portion 331 protruding from the high back portion 331 in the radial direction of the partition wall 33. 31, and the underside 12L of the first side portion 12 facing the main surface 30S is positioned at a position equal to or higher than the height of the upper surface 332T of the low back portion 332 from the main surface 30S and lower than the height of the upper surface 331T of the high back portion 331 from the main surface 30S, and the underside 12L of the first side portion 12 covers the entire space SP formed by the side surface 11S of the first main body portion 11 facing in the circumferential direction, the side surface 22S of the second side portion 22 adjacent to the side surface 11S, and the top of the low back portion 332 on the center 30C side of the opening 30H.

[0062] According to such a sealing device 1, the lower surface 12L of the first side portion 12 covers the entire space SP formed by the side surface of the first main body portion 11 facing the circumferential direction of the opening 30H, the side surface of the second side portion 22 adjacent to the side surface, and the top of the low back portion 332 on the center side of the opening 30H, so that it is possible to suppress the intrusion of outside air into the internal space 101S of the optical fiber drawing furnace 100 through the space SP. Also, in the sealing device 1, the lower surface 12L of the first side portion 12 of the first blade 10 is farther away from the main surface 30S than the upper surface 332T of the low back portion 332, so that the first blade 10 can move so that the first blade 10 and the low back portion 332 overlap. Therefore, even when the first blade 10 moves, the lower surface 12L of the first side portion 12 can cover the entire space SP from above.

[0063] Furthermore, aspect 2 of the present invention is a sealing device 1 of aspect 1, characterized in that the first body portion 11 further has a first body inner portion 113 that is provided on the center 30C side relative to the first body intermediate portion 112, and the width of the first body intermediate portion 112 in a direction perpendicular to the movement direction of the first blade 10 and parallel to the main surface 30S becomes smaller from the outer edge 351 side of the blade casing 30 toward the center 30C, and the width of the first body inner portion 113 in a direction perpendicular to the movement direction of the first blade 10 and parallel to the main surface 30S is smaller than the width of the first body intermediate portion 112, and becomes smaller from the outer edge 351 side of the blade casing 30 toward the center 30C.

[0064] According to the sealing device 1 having this configuration, the widths of the first body intermediate portion 112 and the first body inner portion 113 become smaller from the outer edge 351 side toward the center 30C side, so that when the first blade 10 moves toward the outer edge 351 side, the first blade 10 is easily separated from the second blade 20. Therefore, for example, when the first blade 10 and the second blade 20 are pressed by the side surface 201 of the optical fiber preform 200 in a state where the first blade 10 and the second blade 20 are in contact with the optical fiber preform 200 and move toward the outer edge 351 side, the first blade 10 and the second blade 20 can be easily moved. Moreover, since the width of the first body inner portion 113 is smaller than that of the first body intermediate portion 112, the diameter of the optical fiber preform 200 becomes larger, and even when the first blade 10 is pushed by the side surface 201 of the optical fiber preform 200 as described above, the first blade 10 can be moved further toward the outer edge 351, and the first blade 10 can be more reliably accommodated between the pair of partition walls 33. Furthermore, when the side surface 112S of the first body intermediate portion 112 faces the side surface 221S of the second lateral outer portion 221 and the side surface 113S of the first body inner portion 113 faces the side surface 222S of the second lateral inner portion 222, the gap between the side surface 11S of the first body portion 11 and the side surface 22S of the second lateral portion 22 can be made smaller, and intrusion of outside air into the internal space 101S of the optical fiber drawing furnace 100 can be more effectively suppressed. Furthermore, since the width of the first main body inner portion 113 is smaller than that of the first main body intermediate portion 112, the width of the second lateral inner portion 222 of the second lateral portion 22 can be made larger than when the width of the first main body inner portion 113 is the same as that of the first main body intermediate portion 112, and the overlapping area between the lower surface 12L of the first lateral portion 12 and the upper surface 22T of the second lateral portion 22 can be made larger, thereby preventing air from entering between the first blade 10 and the second blade 20.

[0065] Furthermore, aspect 3 of the present invention is a sealing device 1 of aspect 1 or 2, characterized in that each of the pair of second lateral portions 22 has a second lateral outer portion 221 and a second lateral inner portion 222 that is provided closer to the center 30C than the second lateral outer portion 221, and each side surface 221S of the second lateral outer portion 221 facing in the circumferential direction of the opening 30H is shaped to conform to the side surfaces 33S of a pair of partition walls 33 that sandwich the second accommodating portion 32, and any portion of the side surface 222S of the second lateral inner portion 222 facing in the circumferential direction of the opening 30H is provided closer to the first blade 10 adjacent to the second lateral outer portion 221 than the side surface 221S of the second lateral outer portion 221 facing in the circumferential direction of the opening 30H.

[0066] With this configuration, when the second blade 20 moves toward the outer edge 351, the movement of the second side portion 22 in that direction is blocked by the partition wall 33, and the second blade 20 is prevented from moving too far away from the opening 30H.

[0067] Furthermore, aspect 4 of the present invention is a sealing device 1 of aspect 3, characterized in that the distance between the side surfaces 222S of a pair of second lateral inner portions 222 in a direction perpendicular to the movement direction of the second blade 20 and parallel to the main surface 30S becomes smaller from the outer edge 351 side toward the center 30C side.

[0068] This configuration can facilitate the radial movement of the second blade 20. In addition, this configuration can provide a structure in which the inner tip portion 20I on the opening 30H side of the second body portion 21 of the second blade 20 can easily come into contact with the optical fiber preform 200, and when the optical fiber preform 200 having the outer diameter fluctuating portion is moved in the optical fiber drawing furnace 100 while being kept in contact with the corner portion of the inner tip portion 20I of the second blade 20, the second blade 20 can be reliably retreated in the direction away from the center 30C of the opening 30H.

[0069] A fifth aspect of the present invention is the sealing device of the third aspect, characterized in that the shape of the side surface 11S of the first main body portion 11 and the shape of the side surface 22S of the second lateral portion 22 are complementary to each other.

[0070] With this configuration, the side surface 11S of the first main body portion 11 and the side surface 22S of the second side portion 22 can be brought closer to each other than when the shape of the side surface 11S of the first main body portion 11 and the shape of the side surface 22S of the second side portion 22 are not complementary to each other. Therefore, the gap between the side surface 11S and the side surface 22S can be made smaller, and the intrusion of outside air into the internal space 101S can be further suppressed.

[0071] In addition, aspect 6 of the present invention is a sealing device 1 of any of aspects 1 to 5, characterized in that the apex of the high back portion 331 on the center 30C side has an end face 331I facing the center 30C side, the first side portion 12 faces the outer edge 351 side and has an end face 12O opposite the end face 331I of the high back portion 331, and the width of the end face 331I of the high back portion 331 in a direction perpendicular to the direction from the center 30C side of the partition 33 toward the outer edge 351 side and parallel to the main surface 30S is smaller than the width of the end face 12O of the first side portion 12 in the above direction.

[0072] According to such a configuration, a part of the first side portion 12 can protrude into the second housing portion 32. In this case, the distance of the gap between the upper surface 22T of the second side portion 22 and the lower surface 12L of the first side portion 12 can be made longer than when the first side portion 12 does not protrude into the second housing portion 32. Therefore, the intrusion of outside air into the internal space 101S can be further suppressed.

[0073] Furthermore, aspect 7 of the present invention is a sealing device 1 of any of aspects 1 to 6, characterized in that the first side portion 12 has an end face 12O facing the outer edge 351, and the second main body outer portion 211 has an end face 211I facing the center 30C, and when the first blade 10 and the second blade 20 are moved toward the center 30C, the end face 12O of the first side portion 12 and the end face 211I of the second main body outer portion 211 face each other with a gap between them.

[0074] According to this configuration, when the moving speeds of first blade 10 and second blade 20 are different, first blade 10 and second blade 20 can move more reliably than when end surface 12O and end surface 211I contact each other.

[0075] Furthermore, aspect 8 of the present invention is a sealing device according to any of aspects 1 to 7, characterized in that at least one of the first blade 10 and the second blade 20 has a curved surface whose inclination direction gradually approaches the height direction so that the thickness of the blade becomes smaller from at least one of the upper surface, which is the uppermost surface in the height direction of the blade, and the lower surface, which is the lowermost surface in the height direction, to the inner tip portion 10I, 20I that protrudes most toward the center 30C of the opening 30H.

[0076] In the sealing device 1 of this embodiment, the first blade 10 or the second blade 20 having a curved surface does not have an angular edge between at least one of the upper surface and the lower surface and the inner tip portion 10I, 20I. Therefore, when the optical fiber preform 200 moves upward or downward, for example, even if the diameter of the optical fiber preform 200 varies in the longitudinal direction of the optical fiber preform 200 or the optical fiber preform 200 is inclined, the optical fiber preform 200 can contact the curved surface. Specifically, when a curved surface is provided from the upper surface of the first blade 10 or the second blade 20 to the inner tip portion 10I, 20I, the optical fiber preform 200 can contact the curved surface when the optical fiber preform 200 moves downward, and when a curved surface is provided from the lower surface of the first blade 10 or the second blade 20 to the tip portion, the optical fiber preform 200 can contact the curved surface when the optical fiber preform 200 moves upward. Therefore, compared with a case where the edges between the main surface and the end surface of the first blade 10 or the second blade 20 are angular, in other words, a case where the edges between the top and bottom surfaces and the tip of the first blade 10 or the second blade 20 are all angular, the optical fiber preform 200 is caught by the first blade 10 or the second blade 20, and the first blade 10 or the second blade 20 can be prevented from not moving in the radial direction of the opening 30H. Therefore, even if it is desired to move the optical fiber preform 200 upward or downward in a state where the side surface 201 of the optical fiber preform 200 is in contact with the end of the first blade 10 or the second blade 20, the first blade 10 or the second blade 20 can be moved more reliably in the radial direction of the opening 30H. Note that the upward direction is the direction in which the optical fiber preform 200 moves away from the optical fiber drawing furnace 100, and the downward direction is the direction in which the optical fiber preform 200 approaches the optical fiber drawing furnace 100.

[0077] Furthermore, aspect 9 of the present invention is a sealing device of any of aspects 1 to 8, in which at least one of the gaps between the side surface 111S of at least one first main body outer portion 111 facing in the circumferential direction and the end surface 11O of the first main body portion 11 facing the outer edge 351, and the gap between the side surface 211S of at least one second main body outer portion 211 facing in the circumferential direction and the end surface 21O of the second main body portion 21 facing the outer edge 351, is chamfered.

[0078] According to this aspect, even if the blade to be replaced interferes with other components or falls to the ground during assembly of the seal device 1 or replacement of the first blade 10 or the second blade 20, damage or breakage of the blade or other components that interfere with the blade can be suppressed compared to a case in which the areas between the side surface 111S and the end surface 11O and between the side surface 211S and the end surface 21O are not chamfered. In the above embodiment, the areas between the side surface 111S and the end surface 11O and between the side surface 211S and the end surface 21O are chamfered, but only one of the areas between the side surface 111S and the end surface 11O and the area between the side surface 211S and the end surface 21O may be chamfered. [Industrial Applicability]

[0079] As described above, according to the present invention, a sealing device capable of preventing outside air from entering a furnace is provided, and it is expected that the device will be useful in the field of optical fiber manufacturing. [Explanation of symbols]

[0080] 1. Sealing device 10. First blade 11...First body part 111...First main body outer part 112...First body middle part 113... First body inner part 12...1st lateral part 20...Second blade 21...Second body part 211...Second main body outer part 212...Second body inner part 22...Second lateral part 221...Second lateral outer part 222...Second lateral inner part 30...Blade housing 30H...Aperture 31...First housing section 32...Second housing section 33...bulkhead 331...Tall back 332...low back 100···Optical fiber drawing furnace 200 Optical fiber base material

Claims

1. a blade container having an opening into which an optical fiber preform can be inserted and a main surface extending outside the opening; and a plurality of first blades and a plurality of second blades arranged alternately along a circumferential direction of the opening and movable along the main surface in a radial direction of the opening, wherein each of the first blades and each of the second blades come into contact with an optical fiber preform inserted from an upper opening of an optical fiber drawing furnace through the opening, thereby sealing a gap between the optical fiber preform and the upper opening, the first blade has a first body portion including a first body intermediate portion and a first body outer portion provided on an outer edge side of the blade container relative to the first body intermediate portion, and a pair of first side portions protruding from the first body portion in the circumferential direction of the first body portion, the second blade has a second body portion including a second body inner portion and a second body outer portion provided closer to an outer edge of the blade container than the second body inner portion, and a pair of second side portions protruding from the second body portion in the circumferential direction of the second body portion, the blade housing has a plurality of first housing sections arranged along the circumferential direction and capable of housing the first main body outer portion, a plurality of second housing sections arranged alternately with the first housing sections along the circumferential direction and capable of housing the second main body outer portion, and a partition wall separating the first housing section and the second housing section adjacent to each other, The partition wall has a high back portion and a low back portion protruding from the high back portion in the radial direction of the partition wall and having a height from the main surface lower than that of the high back portion, a lower surface of the first side portion facing the main surface is disposed at a position equal to or higher than the height of the upper surface of the low back portion from the main surface and lower than the height of the upper surface of the high back portion from the main surface; The lower surface of the first side portion covers the entire space formed by the side surface of the first main body portion facing in the circumferential direction, the side surface of the second side portion adjacent to the side surface, and the top of the low back portion on the center side of the opening. A sealing device characterized by:

2. The first main body portion further includes a first main body inner portion provided closer to the center than the first main body intermediate portion, a width of the first body intermediate portion in a direction perpendicular to a moving direction of the first blade and parallel to the main surface becomes smaller from an outer edge side of the blade container toward the center side, The width of the first main body inner portion in a direction perpendicular to the moving direction of the first blade and parallel to the main surface is smaller than the width of the first main body intermediate portion, and decreases from the outer edge side of the blade container toward the center side. The sealing device according to claim 1 .

3. Each of the pair of second side portions has a second outer side portion and a second inner side portion provided closer to the center than the second outer side portion, each side surface of the second lateral outer portion facing in the circumferential direction has a shape that follows a pair of side surfaces of the partition walls that sandwich the second accommodation portion; Any portion of a side surface of the second circumferentially facing inner lateral portion is provided closer to the first blade adjacent to the second circumferentially facing outer lateral portion than a side surface of the second circumferentially facing outer lateral portion. The sealing device according to claim 1 .

4. A distance between the side surfaces of the pair of second lateral inner portions in a direction perpendicular to a moving direction of the second blade and parallel to the main surface becomes smaller from the outer edge side toward the center side. The sealing device according to claim 3 .

5. The shape of the side surface of the first main body portion and the shape of the side surface of the second side portion are complementary to each other. The sealing device according to claim 3 .

6. The top of the high back portion on the center side has an end surface facing the center side, the first side portion has an end surface facing the outer edge side and opposing the end surface of the high back portion, The width of the end face of the high back portion in a direction perpendicular to a direction from the center side to the outer edge side of the partition wall and parallel to the main surface is smaller than the width of the end face of the first side portion in the direction perpendicular to the direction. The sealing device according to claim 1 .

7. The first side portion has an end surface facing the outer edge side, The second main body outer portion has an end surface facing the center side, When the first blade and the second blade are moved most toward the center, the end surface of the first side portion and the end surface of the second main body outer portion face each other with a gap therebetween. The sealing device according to claim 1 .

8. At least one of the first blade and the second blade has a curved surface whose inclination direction gradually approaches the height direction from at least one of an upper surface, which is the uppermost surface in the height direction of the blade, and a lower surface, which is the lowermost surface in the height direction of the blade, to a tip portion that protrudes most toward the center so that the thickness of the blade becomes smaller. A sealing device according to any one of claims 1 to 7.

9. At least one of a side surface of at least one of the first main body outer parts facing in the circumferential direction and an end surface of the first main body part facing the outer edge side, and a side surface of at least one of the second main body outer parts facing in the circumferential direction and an end surface of the second main body part facing the outer edge side are chamfered. A sealing device according to any one of claims 1 to 7.

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