JP6340941B2 - Optical fiber cooling device and optical fiber manufacturing method - Google Patents

Description

  The present invention relates to an optical fiber cooling device and an optical fiber manufacturing method.

  In general, an optical fiber is a glass fiber that has been reduced in diameter by heating and softening the lower end side of an optical fiber preform made of a material such as quartz, and stretching the softened portion by applying tension. Further, it can be obtained by coating a resin around it. The process of reducing the diameter of the optical fiber preform to form an optical fiber is called drawing. The drawn optical fiber is taken down to the downstream side of the production line by take-up means such as a capstan roller and wound around a bobbin or the like.

  When manufacturing an optical fiber as described above, the glass fiber drawn from the optical fiber preform is passed through the cooling device. In this cooling device, for example, a cooling gas having a high heat transfer coefficient such as helium gas is blown onto the glass fiber, thereby forcibly cooling the glass fiber. As a cooling device for cooling a glass fiber, a device having a halved structure and including a pair of cooling device bodies that can be opened and closed is known (for example, see Patent Document 1). In this cooling device, a pair of cooling device main bodies are brought into contact with each other and closed to form an insertion hole through which the glass fiber can be inserted, and the glass fiber is cooled in the insertion hole.

JP 2013-220988 A

  The cooling device main body in such a cooling device is often formed of a material having high thermal conductivity such as aluminum, and the cooling device is operated by a cooling gas for cooling the optical fiber formed in a high temperature state. Sometimes, for example, it is cooled from room temperature (25 ° C.) to a very low temperature. Thus, since the cooling device body repeats between normal temperature (when the device is stopped) and extremely low temperature (when the device is operating), the cooling device body repeats thermal expansion and contraction. As a result, the abutting surfaces themselves are distorted, and gaps are formed between the abutting surfaces, so that relatively expensive cooling gas may leak from the gaps to the outside of the apparatus.

  Therefore, an object of the present invention is to provide an optical fiber cooling device and an optical fiber manufacturing method capable of suppressing cooling gas leakage and improving cooling efficiency.

In order to achieve the above object, an optical fiber cooling device according to an aspect of the present invention includes a pair of cooling device main bodies that form insertion holes through which optical fibers can be inserted by being butted against each other. An optical fiber cooling device for cooling a passed optical fiber,
A support member for supporting each of the pair of cooling device bodies along the traveling direction of the optical fiber;
Each of the pair of cooling device main bodies is fixed to the support member by a fixing member in part, and is connected to the support member by a connection member that can slide in the traveling direction of the optical fiber in the other part.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling device for optical fibers which can suppress cooling gas leak and can improve cooling efficiency can be provided.

It is a schematic block diagram of the optical fiber manufacturing apparatus provided with the cooling device for optical fibers which concerns on one Embodiment of this invention. It is a front view which shows the cooling device for optical fibers of an open state at the time of apparatus stop. It is the top view to which a part of cooling device for optical fibers of Drawing 2 was expanded. It is a front view which shows the cooling device for optical fibers of the closed state at the time of apparatus operation. It is the top view to which a part of cooling device for optical fibers of Drawing 4 was expanded. It is the front view which showed typically the curvature which generate | occur | produces in a cooling device main body.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.
An optical fiber cooling device according to the present invention includes (1) a pair of cooling device main bodies that form insertion holes through which optical fibers can be inserted by being abutted with each other, and cool the optical fibers that are passed through the insertion holes. A cooling device for an optical fiber, further comprising a support member that supports each of the pair of cooling device bodies along the traveling direction of the optical fiber, and each of the pair of cooling device bodies is partially supported by the fixing member. In addition to being fixed, it is connected to the supporting member by a connecting member that can slide in the traveling direction of the optical fiber in other portions.

  In the above optical fiber cooling device, the pair of cooling device main bodies forming the insertion holes are supported and fixed by the support members so as not to warp from the traveling direction (longitudinal direction) of the optical fiber. For this reason, according to said optical fiber cooling device, the leakage of the cooling gas from the insertion hole which a pair of cooling device main body forms can be suppressed, and the cooling efficiency of the optical fiber cooling device can be improved.

  More specifically, when the pair of cooling device main bodies are fixed to the support members at both ends in the traveling direction of the optical fiber, the expansion / contraction difference due to the temperature change between the cooling device main body and the support members is hindered ( May not be absorbed). Specifically, when the optical fiber cooling device is operated and cooled to an extremely low temperature, the cooling device main body made of, for example, aluminum shrinks and the central portion is recessed. In this state, the central portion is pushed by the open / close cylinder, and the cooling device body is straightened. However, when it returns to normal temperature after that, since the aluminum which comprises a cooling device main body expands rather than the SUS material which comprises a support member, for example, curvature will remain in the form which the center part swells. However, according to the optical fiber cooling device of the above configuration (1) or the like, a part (for example, an end portion) of the cooling device main body is connected to the support member by the slidable connection member. It can be slid so as to eliminate the warp, and the warp due to the thermal expansion described above can be eliminated. As a result, the cooling device can be fixed in a state in which the warp has been eliminated (or while the warp is eliminated), so that the leakage of the cooling gas from the insertion hole formed by the cooling device body can be further suppressed, and the optical fiber can be used. The cooling efficiency of the cooling device can be further improved.

(2) Each of the pair of cooling device main bodies may be connected to the support member by a slidable connection member at both ends in the traveling direction of the optical fiber.
(3) The support member may be stronger than the pair of cooling device main bodies. Thereby, a pair of cooling device main body can be reliably supported with a supporting member.
(4) Drive means for abutting the pair of cooling device main bodies to each other is further provided, and each of the pair of cooling device main bodies may be fixed to the support member by a fixing member at the central portion where the drive means is disposed. Good.
In addition, you may make it manufacture an optical fiber using the cooling device for optical fibers mentioned above.

[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

  First, an optical fiber manufacturing process in which an optical fiber cooling device according to an embodiment of the present invention is used will be described. FIG. 1 is a schematic configuration diagram of an optical fiber manufacturing apparatus including an optical fiber cooling device according to an embodiment of the present invention. As shown in FIG. 1, the optical fiber manufacturing apparatus 1 includes a heating furnace 2 that heats the optical fiber preform G on the most upstream side. The heating furnace 2 includes a cylindrical furnace core tube 3 to which an optical fiber preform G is supplied, and a heating element 4 surrounding the furnace core tube 3. A purge gas such as helium or nitrogen is supplied to the heating furnace 2 in the heating region.

  The lower end side of the optical fiber preform G supplied into the heating furnace 2 is heated and softened in the heating region, and is stretched downward to be reduced in diameter. The optical fiber before resin coating (hereinafter referred to as “glass fiber”). G1 is formed.

  A cooling device 7 using a cooling gas such as helium gas is provided on the downstream side of the heating furnace 2. The glass fiber G <b> 1 immediately after leaving the heating furnace 2 is forcibly cooled by the cooling device 7. Thereby, the glass fiber G1 is rapidly cooled from several hundred degrees C. to near room temperature.

  On the downstream side of the cooling device 7, for example, a laser beam type outer diameter measuring device 8 is provided, and the outer diameter of the glass fiber G1 exiting the cooling device 7 is measured by the outer diameter measuring device 8, The outer diameter of the glass fiber G1 at the time of drawing is managed.

  On the downstream side of the outer diameter measuring device 8, a die 9 for applying an ultraviolet curable resin to the glass fiber G1 and an ultraviolet irradiation device 10 for curing the applied ultraviolet curable resin are sequentially provided. . The glass fiber G1 that has passed through the die 9 and the ultraviolet irradiation device 10 is formed with an ultraviolet curable resin coating layer on the outer periphery thereof to form an optical fiber G2.

  Thereafter, the optical fiber G2 is drawn into a capstan 13 via guide rollers 11 and 12, and sent to a take-up bobbin 17 via a screening device 14 and dancer rollers 15 and 16, and taken up.

  Next, the structure of the cooling device 7 provided in the optical fiber manufacturing apparatus 1 will be described in detail.

  FIG. 2 is a front view showing the cooling device that is open when the device is stopped, and FIG. 3 is an enlarged plan view of a part of the cooling device shown in FIG. 4 is a front view showing the cooling device in a closed state when the device is in operation, and FIG. 5 is an enlarged plan view of a part of the cooling device shown in FIG. As shown in FIGS. 2 to 5, the cooling device 7 includes a pair of cooling device main bodies 21 </ b> A and 21 </ b> B and is a half-structured device that can be opened and closed.

  The cooling device main bodies 21A and 21B are each formed, for example, from a substantially rectangular parallelepiped aluminum block body, and are fixed and supported on the back by support members 25A and 25B via a plurality of bolts 26A and 26B. The support members 25A and 25B are made of high-rigidity members such as SUS, for example, and the cooling device main bodies 21A and 21B are fixed and supported by the high-rigidity support members 25A and 25B so that they are not easily distorted. It is configured. The support members 25A and 25B may be made of a material having higher strength (tensile strength) than the cooling device main bodies 21A and 21B, and may be made of a material other than SUS. Further, the support members 25A and 25B are connected to the driving means 27A and 27B on the back surfaces thereof. The drive means 27A and 27B are, for example, open / close cylinders. Each of the cooling device main bodies 21A and 21B is moved and abutted in directions approaching each other or moved away from each other by a driving operation by the driving means 27A and 27B.

  The cooling device main bodies 21A and 21B are fixed to the supporting members 25A and 25B by bolts 26A and 26B, which are fixing members, at the center in the longitudinal direction (traveling direction of the optical fiber). On the other hand, the cooling device main bodies 21A and 21B are connected to the support members 25A and 25B via the slide members 50A and 50B by bolts 26A and 26B at both ends in the longitudinal direction. By arranging slide members 50A and 50B between the bolts 26A and 26B located at both ends in the longitudinal direction and the respective cooling device main bodies 21A and 21B, the bolts 26A and 26B are connected to the cooling device main bodies 21A and 21B. It can be slid in the longitudinal direction relative to 21B. The slide members 50A and 50B are provided, for example, on the rear surfaces of the cooling device main bodies 21A and 21B, and are configured by grooves or the like in which the tip ends of the bolts 26A and 26B can slide. Connection can be made while allowing elongation in the longitudinal direction. The bolts 26A and 26B and the slide members 50A and 50B are collectively referred to as a connection member.

  Further, as shown in FIG. 3 and the like, the cooling device main bodies 21A and 21B have abutting surfaces 20A and 20B facing each other in the vicinity of the center, and the abutting surfaces 20A and 20B have a triangular shape in plan view. Grooves 28A and 28B exhibiting the above are formed. When the cooling device main bodies 21A and 21B are abutted with each other, a rectangular insertion hole 29 is formed by the grooves 28A and 28B as shown in FIG. The glass fiber G1 drawn from the optical fiber preform G is inserted into the insertion hole 29 and cooled. The shape of the groove portions 28A and 28B is not limited to a triangular shape in plan view, and may be a quadrangular shape or a semicircular shape.

  The cooling device main bodies 21A and 21B are provided with blowout ports 31A and 31B for blowing out the cooling gas at a plurality of longitudinal positions along the glass fiber G1, and a cooling gas such as helium is supplied to these blowout ports 31A and 31B. The cooling gas supply pipes 32A and 32B to be connected are connected. In each cooling device main body 21 </ b> A, 21 </ b> B, the cooling gas is supplied from the cooling gas supply pipes 32 </ b> A, 32 </ b> B, so that the cooling gas is ejected from the outlets 31 </ b> A, 31 </ b> B toward the center of the insertion hole 29. Thereby, the glass fiber G1 is cooled.

  The cooling device main bodies 21A and 21B have recesses 24A and recesses 24B formed on both sides of the groove portions 28A and 28B on the facing surfaces 20A and 20B facing each other. An elastic member 22 is attached to one of the recesses 24A and 24B, and a protrusion 23 is provided on the surface of the recess facing the recess.

  The elastic member 22 has a rectangular parallelepiped shape and is an elastic member that is deformed by being brought into contact with the protruding portion 23. Examples of the elastic member 22 include a member used for packing and a rubber member. Examples thereof include silicone rubber and urethane rubber. Is preferred. In particular, silicone rubber is suitable because it has a wide heat-resistant temperature range and can withstand contact with high-temperature glass and low-temperature use. By adjusting the thickness of the elastic member 22, it is possible to widen a region (width) in which airtightness with the protrusion 23 can be ensured. That is, when the thickness of the elastic member 22 is increased, the degree of absorption (width) of the displacement of the protrusion 23 can be increased. On the other hand, it is necessary for the elastic member 22 to be embedded in the elastic member 22 reliably and without being damaged, and from such a viewpoint, the elastic member 22 is easily crushed. For example, the elastic modulus is preferably 0.8 MPa or less.

  The protrusion 23 is a member that can be abutted with the elastic member 22 and can deform the elastic member 22, and examples thereof include a member made of metal. The protrusion 23 may be a member that is continuous in the longitudinal direction, or may be a member that is partially interrupted in the longitudinal direction. Moreover, in this embodiment, although the projection part 23 is integrally formed as a part of cooling device main body 21A, 21B, you may make it provide as a cooling device main body and another member. In the cooling device 7, when the cooling device main bodies 21 </ b> A and 21 </ b> B are closed in order to perform cooling, the protrusion 23 of the cooling device main body 21 </ b> B is embedded so as to abut against the elastic member 22 of the cooling device main body 21 </ b> A. The protrusion 23 of the apparatus main body 21A is embedded so as to abut against the elastic member 22 of the cooling apparatus main body 21B. And even if some distortion generate | occur | produces in butt | matching surface 20A, 20B etc. of cooling device main body 21A, 21B by butt | matching with such an elastic member 22 and the projection part 23, the insertion hole located between both butt | matching parts The internal airtightness centering on 29 can be improved, and leakage of the cooling gas to the outside can be reduced.

  When the glass fiber G1 is cooled using the cooling device 7 having such a structure, first, as shown in FIGS. 2 and 3, the glass fiber G1 is positioned at the center and the cooling device main bodies 21A and 21B are opened. In this state, a constant flow of cooling gas is started to flow from the outlets 31A and 31B. Then, after starting to flow the cooling gas, the cooling device main bodies 21A and 21B are moved to the center side by the driving means 27A and 27B, and the cooling device 7 is closed. At this time, the groove portions 28A and 28B form an insertion hole 29 through which the glass fiber G1 is passed.

  When the cooling device main bodies 21A and 21B are closed, the protrusion 23 of the cooling device main body 21B is abutted against the elastic member 22 of the cooling device main body 21A, and the protrusion 23 of the cooling device main body 21A is It is abutted against the elastic member 22, and airtightness with the outside is ensured in the facing region centered on the insertion hole 29.

  By the way, in the cooling device 7, the cooling device main bodies 21A and 21B made of aluminum or the like are fixed at the center by high-rigid support members 25A and 25B made of SUS or the like, while being slidably connected at both ends. I have to. If the bolts 26A and 26B at both upper and lower ends in the longitudinal direction are also fixed to the cooling device main bodies 21A and 21B, the expansion / contraction difference accompanying the temperature change between the cooling device main bodies 21A and 21B and the support members 25A and 25B is hindered. (Cannot be absorbed). That is, when cooling is performed by the cooling device 7, the cooling device main bodies 21 </ b> A and 21 </ b> B are contracted, and the central portion is recessed with respect to the joint. In this state, the central portions of the cooling device main bodies 21A and 21B are pushed by the driving means 27A and 27B via the support members 25A and 25B, so that the cooling device main bodies 21A and 21B become straight. However, when the temperature reaches room temperature again, the cooling device main bodies 21A and 21B made of aluminum or the like expand by the highly rigid support members 25A and 25B such as SUS. As a result, as shown in FIG. 6, the central portions of the cooling device main bodies 21A and 21B swell, warping occurs at both ends of the cooling device main bodies 21A and 21B, the cooling gas leaks, and the cooling efficiency is lowered. There is a possibility. In FIG. 6, the warp occurrence state is emphasized for easy understanding.

  However, in the cooling device 7 according to the present embodiment, the support members 25A and 25B are not simply fixed by the bolts 26A and 26B at the upper and lower ends of the cooling device main bodies 21A and 21B, but the slide members 50A and 50B are provided. The connection positions of the bolts 26A and 26B with respect to the cooling device main bodies 21A and 21B can be slid in the traveling direction of the optical fiber. For this reason, even if the cooling device 7 warps as the temperature changes, it can be fixed in a state in which the warping is suppressed by such a slide mechanism, and cooling gas leaks from the insertion holes 26 at both ends in the longitudinal direction. Suppress. As described above, according to the cooling device 7, the cooling efficiency can be improved. The slide members 50A and 50B can be slidable during operation, but may be fixed during operation.

  As mentioned above, although this invention was demonstrated based on the embodiment, this invention is not limited to said embodiment, A various change can be made. For example, in the above-described embodiment, the cooling device main bodies 21A and 21B are provided with the protrusions 23 and the elastic members 22 are attached to ensure the airtightness of the insertion holes 29. However, the cooling members main body 21A and 21B are supported by the support members 25A and 25B. When the warpage of 21B is sufficiently suppressed, the protrusion 23 and the elastic member 22 may not be provided. Even in this case, since the warpage of the cooling device main bodies 21A and 21B is suppressed, the leakage of the cooling gas can be suppressed and the cooling efficiency can be improved.

7 ... Cooling device, 21A, 21B ... Cooling device main body, 25A, 25B ... Support member, 29 ... Insertion hole, 26A, 26B ... Bolt, 27A, 27B ... Driving means, 50A, 50B ... Slide member, G1 ... Glass fiber.

Claims (5)

A cooling device for an optical fiber comprising a pair of cooling device main bodies forming an insertion hole through which an optical fiber can be inserted by being butted against each other, and cooling the optical fiber passed through the insertion hole,
A support member for supporting each of the pair of cooling device main bodies along the traveling direction of the optical fiber;
Each of the pair of cooling device main bodies is fixed to the support member by a fixing member in part, and is connected to the support member by a connection member that can slide in the traveling direction of the optical fiber in the other part. , Cooling device for optical fiber.   2. The optical fiber cooling device according to claim 1, wherein each of the pair of cooling device main bodies is connected to the support member by the slidable connection member at both ends in the traveling direction of the optical fiber.   The optical fiber cooling device according to claim 1, wherein the support member has higher strength than the pair of cooling device main bodies. Drive means for abutting the pair of cooling device bodies to each other;
The optical fiber cooling according to any one of claims 1 to 3, wherein each of the pair of cooling device main bodies is fixed to the support member by the fixing member at a central portion where the driving unit is disposed. apparatus. The manufacturing method of the optical fiber which manufactures an optical fiber using the cooling device for optical fibers as described in any one of Claims 1-4.

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