WO2018040575A1 - Optical fibre drawing furnace - Google Patents

Abstract

Disclosed is an optical fibre drawing furnace, comprising a furnace body, and further comprising: a furnace core pipe, the furnace core pipe penetrating from a first surface of the furnace body to a second surface of the furnace body, the furnace core pipe comprising a straight barrel portion, a tapered portion and a diameter-reduced pipe portion connected in a one-time fixing manner, the straight barrel portion and the tapered portion being located inside the furnace body, the straight barrel portion being arranged in a first part of the furnace body, the inner diameter of the tapered portion tapering from a central part of the furnace body to a second part of the furnace body, and the diameter-reduced pipe portion being located outside the furnace body; a heating body, the heating body being located inside the furnace body and wrapped around the straight barrel portion and the tapered portion of the furnace core pipe; and a heat preservation body for heat insulation, the heat preservation body being located inside the furnace body and arranged between the heating body and the furnace body.

Description

Fiber drawing furnace Technical field

The invention relates to the technical field of heat treatment processing equipment, in particular to an optical fiber drawing furnace.

Background technique

Optical fiber is a shorthand for optical fiber. It is a fiber made of glass or plastic and can be used as a light-conducting tool. The transmission principle is "total reflection of light". In daily life, fiber is used as a long-distance information transmission because the conduction loss of light in the optical fiber is much lower than that of electricity conduction in the wire.

The fiber drawing furnace is an important device used in the fiber drawing process. The preform is heated to the glass softening point temperature mainly by a heating device, so that the preform can be drawn into a small diameter fiber. Due to the current high requirements on the geometry and accuracy of optical fibers, with the continuous improvement of the technology of optical fiber manufacturers, the high precision and stable performance of optical fibers is the development direction of the current optical fiber market, and the fiber drawing furnace determines the geometry of the optical fiber. The pros and cons of performance.

The current fiber drawing furnace includes a furnace body, a heating device, a furnace core tube and a heat insulator. The heating device, the furnace tube and the heat retaining body are completely housed in the furnace body. The heating device heats the furnace tube and draws the preform into an optical fiber through the furnace tube. The heat insulator completely covers the heating device and the furnace tube. However, after the preform is drawn into an optical fiber, high temperature is not required and only heat preservation is needed to gradually cool the optical fiber to release the internal stress of the optical fiber, otherwise energy is wasted.

Summary of the invention

The technical problem to be solved by the present invention is to provide an optical fiber drawing furnace capable of saving energy.

An optical fiber drawing furnace comprising a furnace body, the furnace body comprising a first surface and a second surface opposite to the first surface, the furnace body further comprising a first portion and a second portion, the first portion being adjacent to the first portion a surface, the second portion is adjacent to the second surface, wherein the fiber drawing furnace further comprises:

a furnace tube, the furnace core tube penetrating from the first surface of the furnace body to the second surface of the furnace body, the furnace core tube comprising a straight tube portion, a reduced diameter portion and a reduced diameter tube portion which are fixedly connected in sequence, The straight tubular portion and the reduced diameter portion are located in the furnace body, the straight tubular portion is disposed at a first portion of the furnace body, and an inner diameter of the reduced diameter portion starts from a central portion of the furnace body toward the furnace The second portion of the body is tapered, the reduced diameter tube portion being outside the furnace;

a heating element, the heating element is located in the furnace body, and is wrapped around a straight portion of the furnace tube and a periphery of the reduced diameter portion to heat the straight portion and the reduced diameter portion of the furnace tube;

The heat insulating body is insulated, and the heat insulating body is located in the furnace body and disposed between the heat generating body and the furnace body.

Further, the fiber drawing furnace further includes a furnace inlet plate located outside the furnace, the furnace inlet plate comprising a first surface and a second surface opposite to the first surface, the furnace inlet plate The second surface is in contact with the first surface of the furnace body, and the furnace inlet plate is formed with a through hole penetrating through the first surface and the second surface for the preform to be worn Passing into the furnace tube, the inlet port of the furnace mouth is further formed with an air inlet hole, the air inlet hole penetrating through the first surface and the second surface, and from the first surface The second surface is inclined toward the through hole.

Further, the fiber drawing furnace further includes an air suction device located outside the furnace body, the air suction device is disposed on the reduced diameter pipe portion, and the air suction device is formed with a plurality of air suction holes, and the air suction hole and the air suction hole The space formed by the reduced diameter pipe portion of the furnace core tube communicates with the external environment.

Further, the fiber drawing furnace further includes an air intake device located outside the furnace body, and the air intake device is disposed at an end of the reduced diameter pipe portion away from the reduced diameter portion.

Further, the air intake device includes a hollow cylinder and a hollow truncated cone fixedly connected to the hollow cylinder, and the cylinder and the truncated cone body are integrally formed.

Further, the end of the reduced diameter pipe portion of the furnace tube is formed with a screw hole, and the cylinder of the air intake device is formed with an external thread that cooperates with the screw hole, the air intake device and the furnace The end of the reduced diameter pipe portion of the core pipe remote from the reduced diameter portion is screwed by the external thread and the screw hole.

Further, the fiber drawing furnace includes a thermocouple that extends from the intermediate portion of the furnace body through the heat insulating body to the heat generating body.

Further, the fiber drawing furnace comprises a pressure measuring device extending from a reduced diameter pipe portion of the furnace core tube into a reduced diameter pipe portion of the furnace core tube.

According to the present invention, the heat generating body is located in the furnace body and is wrapped around the straight portion and the reduced diameter portion of the furnace core tube, and the reduced diameter pipe portion of the furnace core tube is located outside the furnace body to make the heat sink body The fiber is gradually cooled down to release the internal stress of the fiber, thereby saving energy.

DRAWINGS

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a fiber drawing furnace of the present invention for drawing a preform into an optical fiber.

2 is a top plan view of the inlet air inlet plate of the fiber drawing furnace shown in FIG. 1.

3 is a schematic structural view of an air extracting device of the fiber drawing furnace shown in FIG. 1.

4 is a partially enlarged schematic view of the IV of FIG. 1.

Main component symbol description

Fiber drawing furnace	100
Preform	200
optical fiber	300
Furnace body	1
Core tube	2
heating stuff	3
Insulation	4
First surface	11
Second surface	12
first part	13
the second part	14
Straight tube	twenty one
Reduced diameter	twenty two
Reduced diameter pipe	twenty three
end	twenty four
Thermocouple	5
Furnace inlet plate	6
First surface	61
Second surface	62
Through hole	63
Air intake	64
Air suction device	7
Venting hole	71
space	230
Intake device	8
Cylinder	81
Round body	82
External thread	83
Screw hole	84
Pressure measuring device	9

The invention will be further illustrated by the following detailed description in conjunction with the accompanying drawings.

detailed description

The following examples are intended to provide a fuller understanding of the invention, and are not intended to limit the invention.

For the sake of simplicity of description, spatially relative terms such as "upper", "lower" and "lower" are used herein to describe one element or feature and other element(s) or features(s) shown in the drawings. Relationship. Spatially relative terms such as "upper surface", "lower surface", "upper half", "lower half", "upper end" and "lower end" may be used herein to describe some of the features of an element relative to the drawings. The relationship of other features of the elements. The device may be oriented differently (rotated 90 degrees or in other directions) and the spatially relative descriptors used herein should be interpreted accordingly.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the terms "vertical" or the like is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of describing the present invention and simplifying the description, rather than indicating It is to be understood that the device or elements referred to have a particular orientation, are constructed and operated in a particular orientation and are therefore not to be construed as limiting.

As shown in FIG. 1, an optical fiber drawing furnace 100 is used to draw preform 200 into fiber 300. The fiber drawing furnace 100 includes a furnace body 1, a furnace tube 2, a heating element 3 that heats the furnace tube 2, and a heat insulating body 4 that performs heat insulation.

The furnace body 1 includes a first surface 11 and a second surface 12 opposite the first surface 11. In the present embodiment, the first surface 11 is an upper surface of the furnace body 1, and the second surface 12 is a lower surface of the furnace body 1. The furnace body 1 further includes a first portion 13 and a second portion 14. The first portion 13 and the second portion 14 are spaces formed by the furnace body 1. In the present embodiment, the first portion 13 is the upper half of the furnace body 1, and the second portion 14 is the lower half of the furnace body 1. The first portion 13 is adjacent to the first surface 11 and the second portion 14 is adjacent to the second surface 12.

The furnace tube 2 is matched with the preform 200 and a gap of 5-20 mm is ensured with the preform 200 to prevent the preform 200 from directly contacting the heating element 3. The furnace tube 2 is used for heat transfer, and the preform 200 fed from the inlet end of the furnace tube 2 is heated by the heating element 3. The preform 200 is sent out from the outlet end of the furnace tube 2 after being drawn into the optical fiber by heating. Wherein, the inlet end of the furnace tube 2 is the upper end of the furnace tube 2, and the outlet end of the furnace tube 2 is the lower end of the furnace tube 2. Wherein, the preform 200 is suspended and supported and moves downward as the drawing of the optical fiber 300 proceeds. The furnace tube 2 extends through the first surface 11 of the furnace body 1 and the second surface 12 of the furnace body 1. In the present embodiment, the furnace tube 2 extends substantially vertically through the furnace body 1. The furnace tube 2 includes a straight tubular portion 21, a reduced diameter portion 22, and a reduced diameter tubular portion 23 that are fixedly connected in sequence. The straight tubular portion 21 and the reduced diameter portion 22 are located inside the furnace body 1. The straight portion 21 is provided at the first portion 13 of the furnace body 1. In the present embodiment, the reduced diameter portion 22 has a tapered shape, and the inner diameter of the reduced diameter portion 22 tapers from the center of the furnace body 1 toward the second portion 14, and the outer diameter of the reduced diameter portion 22 The same taper is also performed corresponding to the inner diameter of the reduced diameter portion 22. In other embodiments, only the inner diameter of the reduced diameter portion 22 tapers from the center of the furnace body 1 toward the second portion 14. The reduced diameter pipe portion 23 is located outside the furnace body 1. In the present embodiment, the reduced diameter pipe portion 23 is located below the furnace body 1. The reduced diameter pipe portion 23 heat-anneals the optical fiber 300 by using the heat transferred by the reduced diameter portion 22 to extend the release time of the internal stress of the optical fiber 300 to prevent the internal stress of the optical fiber 300 from being released. Therefore, the heat generating body 3 is not required to heat the reduced diameter pipe portion 23, thereby saving energy. The straight tubular portion 21, the reduced diameter portion 22, and the reduced diameter tubular portion 23 may be formed separately or integrally formed. In the present embodiment, the straight tubular portion 21, the reduced diameter portion 22, and the reduced diameter tubular portion 23 are integrally formed.

The heating element 3 is wrapped around the straight portion 21 and the reduced diameter portion 22 of the furnace tube 2. Wherein, the heating element 3 covers the periphery of the portion of the straight tube portion 21 of the furnace tube 2 close to the reduced diameter portion 22, and the preform 200 is passed through the straight portion 21 of the furnace tube 2 Preheat. In the present embodiment, the heating element 3 partially covers the straight portion 21 of the furnace tube 2, such as about 90% of the covered straight portion 21, without completely covering the straight portion of the furnace tube 2 The periphery of 21, thus saving power. In other embodiments, the heating element 3 completely covers the straight portion 21 of the furnace tube 2. The heating element 3 completely covers the periphery of the reduced diameter portion 22 of the furnace tube 2, so that the reduced diameter portion 22 of the furnace tube 2 can heat the preform 200 such that the preform 200 Being brushed.

The heat insulator 4 is disposed between the heat generating body 3 and the furnace body 1. The heat retaining body 4 is configured to separate the heat generating body 3 from the furnace body 1 to prevent heat generated by the heat generating body 3 from being transmitted out of the furnace body 1 through the furnace body 1, thereby reducing drawing Loss of furnace power.

In the present embodiment, the fiber drawing furnace 100 further includes a thermocouple 5. The thermocouple 5 is extended from the intermediate position of the furnace body 1 through the heat retaining body 4 to the heat generating body 3 to detect the temperature of the furnace body 1, so that the temperature of the furnace body 1 can be adjusted according to the temperature of the furnace body 1. The temperature of the heating element 3 is adjusted to achieve the regulation of the drawing temperature of the fiber drawing furnace 100.

In the present embodiment, the fiber drawing furnace 100 further includes a furnace inlet plate 6. The furnace inlet plate 6 is disposed outside the furnace body 1. The furnace inlet plate 6 is fixed to the first surface 11 of the furnace body 1. The furnace inlet plate 6 includes a first surface 61 and a second surface 62 opposite the first surface 61. The second surface 62 of the furnace inlet plate 6 is in contact with the first surface 11 of the furnace body 1. Referring to FIG. 2 at the same time, the furnace inlet plate 6 is formed with a through hole 63. The through hole 63 extends through the first surface 61 and the second surface 62 for the preform 200 to pass through. An inlet hole 64 is formed in the furnace inlet plate 6, and the inlet hole 64 extends through the first surface 61 and the second surface 62, and from the first surface 61 to the first The two surfaces 62 are inclined toward the through holes 63. The air inlet hole 64 is used for the passage of the shielding gas to enter the furnace tube 2, and flows from the top to the bottom along the gap between the furnace tube 2 and the preform 200 to the reduced diameter tube portion. 23. Preventing fluctuations in temperature in the fiber drawing furnace 100 due to fluctuations in the shielding gas flow, ensuring uniform heating of the preform 200, so that the roundness and centering of the optical fiber 300 are good. In the present embodiment, the shielding gas is an inert gas such as argon, helium, nitrogen or the like. The shielding gas serves to prevent oxidative degradation of the furnace tube 2. Wherein, the protective gas simultaneously carries impurities generated by oxidation and crystallization in the furnace tube 2 while flowing from the top to the bottom along the gap between the furnace tube 2 and the preform 200.

In the present embodiment, the fiber drawing furnace 100 further includes an air extracting device 7. The air suction device 7 is disposed outside the furnace body 1. The air suction device 7 is provided in the reduced diameter pipe portion 23 of the furnace tube 2. Referring to FIG. 3 at the same time, the air suction device 7 is formed with a suction hole 71. The air suction hole 71 communicates with the space 230 formed by the reduced diameter pipe portion 23 and the external environment. The air extracting device 7 is configured to extract the gas of the reduced diameter pipe portion 23 out of the reduced diameter pipe portion 23 through the air suction hole 71, thereby ensuring that the shielding gas air flow passes through the variable diameter of the furnace core pipe 2 The time is stable, so that the diameter of the optical fiber is uniform, and the air suction device 7 also extracts the shielding gas carrying impurities from the furnace tube 2, which is advantageous for improving the strength of the optical fiber.

In the present embodiment, the fiber drawing furnace 100 further includes an air intake device 8. The air intake device 8 is disposed outside the furnace body 1. The air intake device 8 is disposed at an end 24 of the reduced diameter pipe portion 23 away from the reduced diameter portion 22. With continued reference to FIG. 4, the air intake device 8 is threadedly coupled to the end 24 of the reduced diameter tubular portion 23. The air intake device 8 includes a hollow cylindrical body 81 and a hollow truncated cone body 82 fixedly connected to the hollow cylindrical body 81. The hollow cylindrical body 81 and the hollow truncated cone body 82 are integrally formed. In the present embodiment, the cylindrical body 81 is disposed on the end 24 of the reduced diameter pipe portion 23, and the circular base body 82 is disposed outside the reduced diameter pipe portion 23. An external thread 83 is formed on the cylindrical body 81. The end 24 of the reduced diameter pipe portion 23 is formed with a screw hole 84. The end portion 24 of the intake device 8 and the reduced diameter pipe portion 23 are screwed by the external thread 83 and the screw hole 84. The air intake device 8 is configured to pass a shielding gas to the reduced diameter pipe portion 23 to seal the reduced diameter pipe portion 23, and prevent outside air from entering the furnace core pipe through the outlet end of the furnace tube 2 , causing the furnace tube 2 to be oxidatively deteriorated.

In the present embodiment, the fiber drawing furnace 100 further includes a pressure measuring device 9. The pressure measuring device 9 extends from the reduced diameter pipe portion 23 into the reduced diameter pipe portion 23. Specifically, the measuring head of the pressure measuring device 9 is disposed in the reduced diameter pipe portion 23. The pressure measuring device 9 is configured to detect a gas pressure in the reduced diameter pipe portion 23, so that the gas pressure in the reduced diameter pipe portion 23 can be adjusted according to the detected gas pressure, so that the reduced diameter pipe The gas pressure in the portion 23 is greater than the pressure of the external environment, preventing external air from intruding into the reduced diameter pipe portion 23.

In the optical fiber drawing furnace 100 of the present invention, the reduced diameter pipe portion 23 is disposed outside the furnace body 1, and the optical fiber 300 is thermally annealed by the heat transferred by the reduced diameter portion 22, thereby saving energy. The impurity-carrying shielding gas can be discharged out of the furnace tube 2 through the reduced diameter pipe portion 23; through the air inlet hole 64, the shielding gas can flow from the top to the bottom into the furnace tube In the second, the temperature fluctuation in the fiber drawing furnace 100 is prevented due to the fluctuation of the shielding gas flow, and the heating of the preform 200 is ensured to be uniform, so that the roundness and the center degree of the optical fiber 300 are good; the air inlet 64 is opened through the air inlet hole 64. Protecting the gas to prevent oxidative degradation of the furnace tube 2; and extracting the gas of the reduced diameter pipe portion 23 out of the reduced diameter pipe portion 23 by the air extracting device 7, thereby ensuring that the shielding gas flow is passing through the furnace core The diameter of the tube 2 is stabilized, so that the diameter of the optical fiber is uniform, and the air suction device 7 also extracts the shielding gas carrying impurities from the furnace tube 2, which is advantageous for improving the strength of the optical fiber 300; Thermocouple 5 to detect the temperature of the furnace body 1 Therefore, the temperature of the heating element 3 can be adjusted according to the temperature of the furnace body 1, and the temperature of the fiber drawing furnace 100 can be adjusted; the air inlet device 8 can be introduced into the reduced diameter pipe portion 23. Protecting the gas to seal the reduced diameter pipe portion 23, preventing outside air from entering the furnace core pipe 2 through the outlet end of the furnace core pipe 2, causing the furnace core pipe 2 to be oxidatively deteriorated; passing the pressure measuring device 9 The gas pressure in the reduced diameter pipe portion 23 is detected, so that the gas pressure in the reduced diameter pipe portion 23 can be adjusted according to the detected gas pressure so that the gas pressure in the reduced diameter pipe portion 23 is greater than the external environment. The pressure prevents the outside air from intruding into the reduced diameter pipe portion 23.

The basic principles and main features of the invention and the advantages of the invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited by the foregoing embodiments, and that the present invention is only described in the foregoing description and the description of the present invention, without departing from the spirit and scope of the invention. Various changes and modifications are intended to be included within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and their equivalents.

Claims (8)

1.  An optical fiber drawing furnace comprising a furnace body, the furnace body comprising a first surface and a second surface opposite to the first surface, the furnace body further comprising a first portion and a second portion, the first portion being adjacent to the first portion a surface, the second portion is adjacent to the second surface, wherein the fiber drawing furnace further comprises:

   a furnace tube, the furnace core tube penetrating from the first surface of the furnace body to the second surface of the furnace body, the furnace core tube comprising a straight tube portion, a reduced diameter portion and a reduced diameter tube portion which are fixedly connected in sequence, The straight tubular portion and the reduced diameter portion are located in the furnace body, the straight tubular portion is disposed at a first portion of the furnace body, and an inner diameter of the reduced diameter portion starts from a central portion of the furnace body toward the furnace The second portion of the body is tapered, the reduced diameter tube portion being outside the furnace;

   a heating element, the heating element is located in the furnace body, and is wrapped around a straight portion of the furnace tube and a periphery of the reduced diameter portion to heat the straight portion and the reduced diameter portion of the furnace tube;

   The heat insulating body is insulated, and the heat insulating body is located in the furnace body and disposed between the heat generating body and the furnace body.
2.  An optical fiber drawing furnace according to claim 1, wherein said fiber drawing furnace further comprises a furnace inlet plate located outside the furnace, said furnace inlet plate comprising a first surface and said first surface a second surface of the furnace inlet plate is in contact with the first surface of the furnace body, and a through hole is formed in the furnace inlet plate, the through hole penetrating the first surface a surface and the second surface for the preform to pass through the furnace tube, the furnace inlet plate further having an air inlet hole, the air inlet hole penetrating the first surface and the The second surface is inclined from the first surface toward the second surface toward the through hole.
3.  An optical fiber drawing furnace according to claim 1, wherein said fiber drawing furnace further comprises an air suction device outside the furnace body, said air suction device being disposed at said reduced diameter pipe portion, said pumping A plurality of air vent holes are formed in the device, and the air vent holes communicate with a space formed by the reduced diameter pipe portion of the furnace tube and an external environment.
4.  An optical fiber drawing furnace according to claim 1, wherein said fiber drawing furnace further comprises an air intake device outside the furnace body, and said air intake device is disposed at said reduced diameter pipe portion away from said reduced diameter One end of the department.
5.  An optical fiber drawing furnace according to claim 4, wherein said air intake means comprises a hollow cylinder and a hollow truncated cone fixedly connected to said hollow cylinder, said cylinder and said The circular table body is integrally formed.
6.  The optical fiber drawing furnace according to claim 5, wherein the end of the reduced diameter pipe portion of the furnace core tube is formed with a screw hole, and the cylinder of the air intake device is formed with a screw hole The mating external thread is screwed to the end of the reduced diameter pipe portion of the furnace tube away from the reduced diameter portion by the external thread and the screw hole.
7.  An optical fiber drawing furnace according to claim 1, wherein said fiber drawing furnace comprises a thermocouple, said thermocouple extending from said heat retaining body to said heat generating body from an intermediate position of said furnace body.
8.  An optical fiber drawing furnace according to claim 1, wherein said fiber drawing furnace comprises a pressure measuring device, said pressure measuring means being directed from said reduced diameter pipe portion of said furnace core tube to said furnace core tube The reduced diameter tube extends inside.

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