Fiber drawing furnace mouth sealing device and control method thereof

Abstract

The invention relates to a fiber drawing furnace mouth sealing device and a control method thereof. The fiber drawing furnace mouth sealing device comprises an extensible sealing circular ring, a connecting piece, an air exhausting and charging device, a laser diameter measuring instrument, an air pressure sensor, and a controller in signal connection with the laser diameter measuring instrument, the air pressure sensor and the air exhausting and charging device and analyzing preform diameter data to control the air exhausting and charging device to perform corresponding air exhausting and charging actions, wherein the laser diameter measuring instrument measures an optical fiber preform diameter d and transmits the diameter to the controller through a data line. The air pressure sensor measures the air pressure p in the extensible sealing circular ring and transmits the air pressure to the controller, and the controller conducts contrast control on air exhausting and charging. The fiber drawing furnace mouth sealing device has the advantages that the size of the extensible sealing circular ring is timely adjusted according to the change of the preform diameter, an optical fiber drawing furnace mouth upper sealing effect is ensured in the whole fiber drawing process, accordingly high-speed stable fiber drawing of an irregular preform is achieved, and raw material cost waste caused by untimely adjustment can be greatly saved due to automatic control.

Description

technical field [0001] The invention relates to the field of optical fiber drawing, in particular to a sealing device for a furnace mouth of a drawing furnace and a control method thereof. Background technique [0002] An optical fiber is produced by a method in which an optical fiber preform mainly composed of silica is lowered from the upper opening of a drawing furnace into a furnace core tube, and the tip of the preform is heated and melted to make the preform The front end is tapered and drawn. At this time, the temperature in the drawing furnace is very high at 1,800-2,200 degrees Celsius, so graphite with excellent heat resistance is used for components of the drawing furnace. This graphite is oxidized and consumed in a high-temperature oxygen-containing atmosphere. In order to prevent the above, it is necessary to keep the inside of the drawing furnace in an atmosphere of rare gas such as argon or helium, or nitrogen (hereinafter collectively referred to as inert g...

AI Technical Summary

Problems solved by technology

The size of this quartz cylinder is fixed, and when selected, its size is usually larger than the thickest part of the preform, so when the diameter of the preform fluctuates or becomes smaller, the size of the cylinder does not correspond This will lead to poor sealing effect of the furnace mouth, air will enter the drawing furnace through the sealing device, and high-quality optical fibers cannot be drawn

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