摘要 |
<p>Process for the manufacture of a cylindrical article made of multicomponent glass, comprising the following operations: - a vertical cylindrical cavity (1) lined with porous membranes (2, 3) is used, whose internal dimensions are very slightly greater than those of the article and in which a cylindrical pedestal (5) can slide, - a stub (11) consisting of glass is provided on the pedestal, - the stub is heated to melting and a gas is injected continuously into the porous membranes in order to maintain a thin layer of gas between them and the molten stub, thus preventing any contact, - the stub is fed in the molten state via the top of the cavity (30) by a continuous dispensing of a powder of the constituents of the glass whose composition is varied in step with the formation of the article, the glass of which the article consists thus having a composition which is variable lengthwise, - the pedestal is moved down in step with the formation of the cylindrical article. <IMAGE></p> |