JP2009018949A - Glass preform drawing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glass preform drawing apparatus wherein its rotating belt is prevented from being molten or damaged in order to heighten the heating temperature in a heating furnace and to heighten the take-up speed at the glass preform take-up section. <P>SOLUTION: In the glass preform drawing apparatus 1, a glass preform 3 is delivered into a heating furnace 5 by a preform delivery section 11 and is pulled out and drawn by a preform take-up section 15. The preform take-up section 15 is characterized in that it is a take-up caterpillar 15A constituted from an endless circular rotating belt 27 that rotates for taking up the glass preform 3 and a plurality of rotating rollers 29 that support the rotating belt 27, and at least one of the rotating rollers 29 is cooled with a cooling medium. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a glass base material stretching apparatus, and more particularly to a glass base material stretching apparatus that draws and stretches a glass base material such as an optical fiber base material from a heating furnace.

  In the conventional glass base material stretching apparatus, a rod-shaped glass base material is inserted into the furnace core from above, and the upper end of the glass base material is held by the base material delivery unit via a dummy lot or the like. It is sent to the heating furnace at an appropriate speed. The lower part of the large-diameter portion of the glass base material is heated by a heating part (heater) of the heating furnace, and the lower end of the heated glass base material is, for example, a caterpillar structure as a base material take-up part. The take-out caterpillar is pulled out to a predetermined outer diameter.

  In order to increase the drawing efficiency in this glass base material drawing device, the take-up speed may be increased. Further, in order to obtain a good appearance by smoothing the appearance of the surface of the glass base material after stretching, heating is performed by increasing the heating temperature of the heating furnace.

  However, since the rotating belt of the take-up caterpillar is made of, for example, a rubber material having a heat-resistant temperature of 200 ° C, when the take-up speed is increased or the heating temperature of the heating furnace is increased, when the take-up caterpillar reaches the take-up caterpillar Since the temperature of the glass base material exceeds 200 ° C., which is the above heat resistance temperature, the rotating belt is melted or damaged.

Therefore, the glass base material stretching apparatus disclosed in Patent Document 1 is provided with a cooling unit in front of the take-up caterpillar, and the stretched base material itself is cooled to melt or damage the rubber material of the rotary belt of the take-up caterpillar. Is preventing.
JP-A-10-338535

  By the way, in the conventional glass base material extending | stretching apparatus of patent document 1, although the extending | stretching base material itself is cooled by providing the cooling unit in front of a taking-up caterpillar, the melting or damage of a caterpillar belt is prevented. If the cooling unit cannot cool the glass base material due to high speed or the internal heat of the glass base material is high, there is a problem that the rotating belt of the take-up caterpillar is melted or damaged.

  The present invention provides a glass base material stretching device that prevents the rotating belt from melting or being damaged, and that increases the heating temperature of the heating furnace and the take-up speed of the glass base material take-up section. For the purpose.

In order to solve the above-described problems, a glass base material stretching apparatus according to the present invention is a glass base material stretching apparatus that feeds a glass base material into a heating furnace by a base material feed section and draws and stretches the glass base material by a base material take-up section. In
The base material take-up section is a take-up caterpillar composed of an endless annular rotary belt that rotates to take up the glass base material and a plurality of rotary rollers that support the rotary belt, and at least one or more The rotating roller is cooled by a cooling medium.

  Moreover, the glass base material extending | stretching apparatus of this invention WHEREIN: In the said glass base material extending | stretching apparatus, it is preferable to provide the flow path through which a cooling medium flows inside the said rotation roller.

  As can be understood from the means for solving the above problems, according to the present invention, the rotating belt of the base material take-up portion is always cooled by the cooled rotating roller, Damage can be prevented. As a result, it is possible to further increase the heating temperature of the heating furnace and increase the take-up speed of the glass base material. For example, by providing a cooling part between the heating furnace and the base material take-up part, even if the glass base material is cooled by the cooling part, the glass base material reaches the base material take-up part without being cooled. Even if the use upper limit temperature of the rotating belt of the base material take-up portion is exceeded, melting or damage of the rotating belt can be prevented for the above reason.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIG. 1, in a glass base material stretching apparatus 1 according to this embodiment, a rod-shaped glass base material 3 is inserted into a furnace core portion 7 of a heating furnace 5 from above, and the upper end of the glass base material 3 is It is held by the base material feed unit 11 via the dummy lot 9 and the like and sent to the heating furnace 5 at an appropriate speed. The lower part of the large-diameter portion of the glass base material 3 is heated by the heating unit 13 (heater) of the heating furnace 5, and the lower end of the heated glass base material 3 is used as a base material take-up part 15. For example, it is pulled out by two take-up caterpillars 15A and 15B having a caterpillar structure and stretched to a predetermined outer diameter.

  A cooling unit 17 is provided between the heating furnace 5 and the base material take-up unit 15. The specific configuration of the cooling unit 17 is not particularly limited. For example, a cooling cylinder 21 that penetrates the glass base material 3 and includes a cooling medium filling chamber 19, and a temperature of the cooling medium in the cooling cylinder 21 is set. The temperature control unit 23 is supplied by being controlled (cooled), and a suction circulation unit 25 that sucks the cooling medium from the cooling cylinder 21 and circulates it to the temperature control unit 23, for example.

  In addition, as a cooling medium used in said cold removal part, there exist low temperature air, other cold / hot gas, low temperature water, low temperature liquid, etc. For example, in the case of low-temperature air, it may be about 10 ° C.

  Further, in the cooling unit 17, there is an inner wall 21A inside the cooling cylinder 21 through which the glass base material 3 is inserted, and the cooling medium is not directly in contact with the outer periphery of the glass base material 3, A direct touch structure may be used.

  Further, the base material take-up part 15 constituting the main part of the embodiment of the present invention will be described in detail. The base material take-up part 15 is an endless annular rotating belt 27 that rotates to take up the glass base material 3. And take-up caterpillars 15 </ b> A and 15 </ b> B composed of a plurality of rotating rollers 29 that support the rotating belt 27. The rotating roller 29 includes a driving roller that drives the rotating belt 27. The two take-up caterpillars 15A and 15B are configured to rotate in a direction in which the glass base material 3 is sandwiched from both sides and drawn downward.

  As shown in FIG. 2, the rotating roller 29 is a so-called “cooling roller” cooled by, for example, cooling water CW as a cooling medium. The rotating roller 29 to be cooled is supported by the support member 35 with the rotating shafts 31 at both ends thereof via bearings 33, and the flow path 37 of the cooling water CW is provided at the center of the rotating shaft 31 at both ends. Is provided. In addition, a supply hose 41 for supplying cooling water CW is connected to an end portion (left end portion in FIG. 2) of one rotary shaft 31 via a rotary joint 39, and an end portion ( A drainage hose 43 for discharging the cooling water CW is connected to the right end portion in FIG.

  In addition, a flow path 45 for cooling water CW is provided inside the rotary roller 29 and communicates with the flow path 37 of the rotary shaft 31 on both ends. In this embodiment, the rotating roller 29 is configured such that the roller cylinder 51 is provided on the outer peripheral side of the central member 47 via a plurality of spacer members 49 arranged at appropriate intervals on the outer periphery on both ends of the central member 47. A flow path 45 is formed in a space between the roller cylinder 51 and the central member 47. Thereby, the flow path 45 is configured to flow evenly near the surface of the rotating roller 29.

  Therefore, since the supply hose 41 and the drainage hose 43 are connected to the rotary shafts 31 on both ends of the rotary roller 29 by the rotary joint 39, there is no problem even if the rotary roller 29 rotates, and the cooling water CW After flowing uniformly from the supply hose 41 through the flow path 37 of the rotary shaft 31 on one side and the flow path 45 inside the rotary roller 29, it is discharged from the drain hose 43 through the flow path 37 of the rotary shaft 31 on the other side. Is done. As a result, the surface of the roller cylinder 51 of the rotating roller 29 is sufficiently cooled, so that the rotating belt 27 passing through the rotating roller 29 is always cooled.

  The plurality of rotating rollers 29 may not be all cooled and may cool at least the rotating roller 29 on the base material 3 side, but it is desirable that as many rotating rollers 29 as possible be cooling rollers. .

  Incidentally, when the glass base material 3 is stretched, the conventional glass base material stretching apparatus provided with the cooling unit 17 is heated to, for example, about 2000 ° C. in the heating furnace 5 and the take-up speed is about 150 mm / min. However, in this embodiment, the take-up speed can be increased to about 300 mm / min at the same heating temperature of about 2000 ° C. as in the prior art.

  From the above, even if the glass base material 3 is cooled by the cooling unit 17, the temperature of the glass base material 3 reaching the base material take-up part 15 remains the same as that of the rubber belt of the rotary belt 27 of the take-up caterpillar 15 </ b> A, 15 </ b> B. Even when the upper limit temperature of 200 ° C. is exceeded, the rotating belt 27 of the take-up caterpillar 15A, 15B is always cooled by the cooled rotating roller 29 (cooling roller). Melting or damage can be prevented. As a result, the heating temperature of the heating furnace 5 can be further increased and the take-up speed of the glass base material 3 can be increased.

It is a schematic explanatory drawing of the glass base material extending | stretching apparatus of embodiment of this invention. It is sectional drawing of the rotating roller of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass base material extending | stretching apparatus 3 Glass base material 5 Heating furnace 9 Dummy lot 11 Base material sending part 13 Heating part 15 Base material taking parts 15A and 15B Take-up caterpillar 17 Cooling part 23 Temperature control part 27 Rotating belt 29 Rotating roller 31 Rotating shaft 35 Support member 37 Channel 39 Rotary joint 41 Supply hose 43 Drain hose 45 Channel 47 Center member 49 Spacer member 51 Roller cylinder CW Cooling water

Claims (2)

In the glass base material stretching device that feeds the glass base material into the heating furnace by the base material delivery section and draws it out by the base material take-up section and stretches it,
The base material take-up section is a take-up caterpillar composed of an endless annular rotary belt that rotates to take up the glass base material and a plurality of rotary rollers that support the rotary belt, and at least one or more The glass base material drawing apparatus, wherein the rotating roller is cooled by a cooling medium.   The glass base material stretching apparatus according to claim 1, wherein a flow path through which a cooling medium flows is provided inside the rotating roller.

Images