JP2819307B2 - Optical fiber preform manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical fiber preform manufacturing apparatus. [Prior Art] Conventionally, an optical fiber preform as a preform for spinning an optical fiber has been manufactured. As a method of manufacturing an optical fiber preform, a core material serving as a central portion of the optical fiber preform is horizontally supported and rotated, and a burner that is movably mounted on a traverse rail and is fed and driven in parallel along the core material. The raw material and fuel are supplied to burn the raw material, and the generated combustion gas is sprayed toward the core material so that the glass component in the combustion gas adheres to the outer periphery of the core material until a predetermined diameter or weight is reached. Although there is a method using a fiber preform, a conventional optical fiber preform manufacturing apparatus based on this type of optical fiber preform manufacturing method has a configuration in which one burner is reciprocated along a core material. Was.

[Problems to be Solved by the Invention] In the production of the optical fiber preform (hereinafter abbreviated as the preform), in order to increase the growth rate of the preform and increase the productivity, for example, a plurality of burners are used in the core material. In this method, it is conceivable that the burner must be stopped except for one burner at both ends of the core material. The rate is low and not effective.

It is also conceivable to perform spraying by arranging a plurality of burners radially toward the core material.
It is difficult to collect waste combustion gases that diffuse radially behind the core (that is, waste gases that do not adhere to the core and are wasted).

The present invention has been made in view of the above circumstances, and can increase the growth rate of an optical fiber preform and increase productivity, does not reduce the operation efficiency of a burner, and has no problem in collecting waste combustion gas. An object is to obtain an optical fiber preform manufacturing apparatus.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a traverse rail with a plurality of carriages reciprocating along individual moving paths parallel to each other in the longitudinal direction of the core material. The burners are provided above each so as to circulate in different annular paths sharing a supply straight path for spraying the combustion gas along the core material.

[Operation] In the above configuration, each burner sprays the combustion gas while sequentially moving from one end of the core to multiple ends on a common straight path along the core. The burner reaching the other end of the core material stops blowing the combustion gas, moves along the return path of the annular path, returns to the one end, and starts blowing the combustion gas again. In this manner, the combustion gas is sprayed while each burner circulates, so that the glass component is laminated on the core material, and the optical fiber preform is grown.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view showing almost the entire optical fiber preform manufacturing apparatus, FIG. 2 is a schematic front view of the apparatus for explaining the movement of each part, and FIG. 3 is a schematic plan view thereof. In these figures, reference numeral 1 denotes an optical fiber preform being manufactured by the present apparatus. 1a is a core remaining as a part of the optical fiber preform at the center of the optical fiber preform 1. Reference numeral 2 denotes a core support rotation mechanism that supports both ends of the core 1a and rotates at a predetermined rotation speed. This core material supporting / rotating mechanism 2 has a configuration in which chucks 5 for gripping the core material 1a are rotatably mounted on frames 4 provided on both sides in the longitudinal direction of the upper surface of the base portion 3, and the chucks 5 are driven to rotate by motors 6, respectively. Yes, and one of the frames 4 is adjustable in longitudinal direction along the pedestal 3 so as to correspond to various lengths of the core 1a.
The core material supporting / rotating mechanism 2 in the illustrated example is provided such that the platform 3 is mounted on a measuring platform (not shown) for detecting the degree of growth of the optical fiber preform 1.

A combustion gas spraying device 7 is installed adjacent to the core support rotation mechanism 2. This combustion gas spraying device 7
Is the lower traverse rail 8 parallel to the core 1a.
And the upper traverse rail 9, and the lower traverse rail 8 has two guide grooves 8 formed in parallel with the core 1a.
Carriages 10, 11 which reciprocate along a, 8b are provided. The carriages 10 and 11 are driven by feed drive motors 12 and 13 along guide grooves 8a and 8b, respectively. Both carriages 10 and 11 have telescopic parts 14 and 15 that can expand and contract vertically.
The first and second burners 18 and 19 are attached to the arms 16 and 17 respectively. Each of the carriages 10 and 11 has a burner 1
A plurality of hoses 20 for supplying raw materials, combustion, seal gas, etc., supplied to the burners 8, 19, or electric parts for the burners 18, 19, and wiring connected to an electric circuit are accommodated, and the carriages 10, 11 Cable racks 21 and 22 that can follow the reciprocating movement of the cable are connected. The burners 18, 19 have a structure having two nozzles 18a, 18a, 19a, 19a, respectively, in the illustrated example, and can be moved and adjusted on the arms 16, 17 in the direction toward the core 1a.

With the above configuration, the first and second two burners 18, 19 are
As shown in FIGS. 2 and 3, an annular path A including a common straight path A 'for spraying combustion gas along the core 1a is circulated as indicated by arrows. That is, it moves linearly from one end (the left end in the figure) to the other end (the right end in the figure) along the core 1a, and expands and contracts at the other end.
The telescopic part is lowered by the contraction, moves in the opposite direction in the lowered state, and after reaching one end side, the elastic parts 14, 15 are extended again, and circulate in the annular path returning to the initial position.

The configuration on the upper traverse rail 9 side is almost the same as the configuration on the lower traverse rail 8 side. That is, on the lower surface of the lower traverse rail 9, carriages 23 and 24 that reciprocate along two guide grooves (not shown) opened in parallel with the core 1a are provided, and the carriages 23 and 24 are respectively connected to the carriages 23 and 24. Feed driving motors 25 and 26 for driving the feed are provided, and arms 30 and 31 are attached to both carriages 23 and 24 via telescopic portions 27 and 28 which can expand and contract vertically. A third burner 32 and a fourth burner 33 are attached, and a cable rack (not shown) that can follow the reciprocating movement is connected to the carriages 23 and 24. The upper burner 32,3
The illustration of the hose connected to 3 is also omitted. According to the above configuration, the third and fourth burners 32 and 33 move the annular path B including the common straight path B '(but the same as the path indicated by A') for blowing the combustion gas along the core 1a by arrows. So that it circulates. That is, it moves linearly from one end to the other end along the core 1a, and the other end extends and contracts.
As it rises by the contraction of 27, 28, it moves in the opposite direction in the ascended state, and after reaching one end, the elastic parts 27, 28 extend again, descend, and circulate in the annular path returning to the initial position. Has become.

3, a two-dot chain line C indicates the reciprocating movement path viewed from the upper surface of the lower one carriage 10 and the upper one carriage 23, and a two-dot chain line D indicates the other lower carriage. A reciprocating path viewed from the upper surface of the carriage 11 and the other upper carriage 24 is shown (however, the positions shown correspond to the reciprocating positions of the telescopic portions 14, 14, 27, and 28).

 The following operation will be described.

The four burners 18, 19, 32, and 33 sequentially move at a predetermined speed on the common straight path A '(= B') along the core 1a with an interval from one end to the other end of the core 1a. The combustion gas is sprayed while the combustion gas contains, for example, gaseous silicon dioxide generated by burning silicon tetrachloride as a raw material together with hydrogen and oxygen as a fuel,
This silicon dioxide is laminated on the outer periphery of the core material 1a, and the base material 1 grows.

The feed driving of the burners 18, 19, 32, and 33 is performed by individually driving the carriages 10, 11, 23, and 24 by the feed driving motors 12, 13, 25, and 26, respectively. The burner reaching the other end of the core 1a stops blowing the combustion gas, moves along the return path of the annular path, and returns to the one end. In the illustrated example, the second, third, and fourth three burners 19, 32, and 33 are blowing the combustion gas, and the first burner 18 is returning to the return path. Since the carriages of each burner are individually driven by the respective feed drive motors, the burners can be returned at a speed sufficiently faster than at the time of spraying. Therefore, the downtime of the burner can be sufficiently shortened, and the operating rate of the burner can be increased. Then, the returned burner starts spraying the combustion gas again at the position of one end of the core material 1.

As described above, since the optical fiber preform is grown while circulating the four burners, the growth rate is sufficiently fast, and the productivity is improved. In addition, since the direction of spraying of each burner is only one as in the case of only one conventional unit, there is no problem that collection of waste combustion gas becomes difficult.

The number of burners to be installed is not limited to four in the embodiment, but may be two or more.

Further, only one traverse rail may be provided, and a plurality of burners may be provided on this one traverse rail. In this case, it is also possible to form the annular path of the burner in a horizontal plane.

[Effects of the Invention] The present invention is configured as described above, and thus has the following effects.

Since a plurality of burners are configured to circulate in an annular path including a common straight path, a plurality of burners can increase the amount of spraying, and at the same time, reduce the downtime of the burner by circulating to increase the operation rate. Accordingly, the growth rate of the optical fiber preform can be remarkably increased, and the productivity can be improved.

Further, since the direction of spraying the combustion gas is the same as the conventional one, there is no difficulty in collecting the waste combustion gas.

In addition, by providing traverse rails up and down,
Two circulation paths can be provided, and a plurality of burners can be used at a high operation rate.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical fiber preform manufacturing apparatus showing one embodiment of the present invention, FIG. 2 is a schematic front view for explaining the movement of each part of the apparatus, and FIG. 3 is a schematic plan view thereof. is there. DESCRIPTION OF SYMBOLS 1 ... Optical fiber preform, 1a ... Core material, 2 ... Core material support rotation mechanism, 7 ... Combustion gas spraying device, 8, 9 ... Traverse rail, 10, 11, 23, 24 ... Carriage, 14 , 15,27,28 …… Expansion part, 16,17,30,31 …… Arm, 18,19,32,33 …… Burner, A, B… Circular path, A ′, B ′… Common straight line Route.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshikatsu Sasakawa 1440 Mutsuzaki, Sakura-shi, Chiba Pref. 18929 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C03B 37/00-37/18

Claims (3)

(57) [Claims] 1. A support / rotation mechanism for horizontally supporting and rotating a core, and a burner movably attached to a traverse rail and driven in parallel along the core to drive a raw material and a fuel to the burner. An optical fiber preform manufacturing apparatus for supplying the raw material, burning the generated combustion gas, spraying the generated combustion gas toward the core material, and attaching a glass component in the combustion gas to the outer periphery of the core material to manufacture an optical fiber preform; The traverse rail is provided with a plurality of carriages that reciprocate along individual movement paths parallel to each other in the core material longitudinal direction, and the burners are shared on each of these carriages, and a common straight path for spraying combustion gas along the core material is shared. An optical fiber preform manufacturing apparatus provided so as to circulate different annular paths. 2. The traverse rails are separately arranged on the upper side and the lower side of the core material, and an annular path of a burner on one traverse rail side is formed above the common straight path, and the other traverse rail side is formed. The optical fiber preform manufacturing apparatus according to claim 1, wherein the annular path of the burner is formed below the common straight path. 3. The optical fiber preform manufacturing apparatus according to claim 1, wherein a burner is attached to each of the carriages via a telescopic part which expands and contracts in a vertical direction.