The Furukawa Electric Co., Ltd.

Tetsuya Kumada

Yasuhiro Naka

Toshihiro Nakamura

Hisashi Koaizawa

Nobuaki Orita

Toshiaki Tateishi

Yoshiyuki Sakata

In a heating drawing, a base material glass plate is heated and softened in a heating furnace, and drawn to a desired thickness to form a glass strip. In the heating drawing, the base material glass plate is heated so that the base material glass plate has a U-shaped temperature distribution in a width direction. Such process can be realized through heating by a heating element which has a non-heating portion at a position opposite to a central portion of the base material glass plate in the width direction and a heating portion on both sides of the non-heating portion. Thus provided is a method of manufacturing a glass strip, the method includes heating and softening the base material glass plate, and drawing the base material glass plate to a desirable thickness to form a glass strip, and is capable of manufacturing a thin, rod-like glass strip with an excellent flatness.

Process for producing glass bar

An optical fiber drawing furnace capable of the prevention of entry of an ambient gas into an inner space thereof both effectively and economically, provided with a lower gas introduction portion through which inert gas is introduced into the inner space of the optical fiber drawing furnace, a chamber separated by a lower partition, and a bottom cover. The lower partition is arranged immediately below the lower gas introduction portion and has a first hole through which the chamber and the inner space are communicated. The bottom cover has a second hole through which the chamber and the atmosphere are communicated. An optical fiber is passed through the first and second holes. A controller detects a differential pressure between a pressure P,in the inner space and a pressure P,in the chamber and controls the suction flow by a pump for evacuating the gas in the chamber to maintain P,>P,The sizes of the first and second holes are defined as (L,/D,)<(L,/D,), where L,and L,are lengths of the holes and D,and D,are the diameters of the holes.

Furnace for forming optical fiber

Growing community of inventors

Tokyo, Japan

Tetsuya Kumada