METHOD OF MAKING PIPES FROM QUARTZ GLASS Russian patent published in 2010 - IPC C03B37/18 

FIELD: chemistry.

SUBSTANCE: method of making pipes from quartz glass relates to fibre optics, particularly to the technology of making accurate-size pipes from quartz glass required for making fibre-optic waveguides used in telecommunication lines, fibre-optic sensors and laser technology. The method involves gas-phase deposition of SiO₂ particles on a horizontal rotating coal-graphite pipe and quartz pipes into which the coal-graphite pipe is inserted, removal of the coal-graphite pipe by burning in an oxygen-containing atmosphere and sintering the porous tubular workpiece. During deposition of SiO₂ particles, the coal-graphite pipe is cooled by blowing its inner channel with an air stream, and the porous workpiece is sintered in an atmosphere containing fluorinating gaseous reagents, preferably SF₆ or SiF₄. Sintering is carried out in two steps. At the first step the outer surface of the porous workpiece is molten while cooling the coal-graphite pipe by blowing its inner channel with an air stream. At the second step final sintering is carried out by putting a mixture of fluorinating gas with oxygen into the coal-graphite pipe.

EFFECT: higher quality of pipes made, lower energy consumption and shorter process of making optical waveguides with simultaneous reduction of optical losses.

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