Process and apparatus for the production of drawn articles of vitreous silica

Claim 1

THE PROCESS OF MAKING HOLLOW SHAPES OF VITREOUS SILICA COMPRISING HEATING A MASS OF SUBSTANTIALLY PURE SILICA TO MOLTEN STATE, DRAWING THE MOLTEN SILICA BETWEEN MEMBERS DEFINING A TUBULAR SHAPE OF FIXED SIZE, PASSING THE MOLTEN SILICA TOWARD AND ALONG A MANDREL OF LESSER SIZE WHEREON THE SILICA IS PERMITTED PARTIALLY TO COOL AND FORM A SHAPE DETERMINED BY THE NUMBERS AND MANDREL, PASSING THE PATIALLY COOLED SILICA THROUGH A PRIMARY ZONE OF CONGELATION WHEREIN THE SHAPED SILICA IS PERMITTED TO FURTHER COOL AND PARTIALLY CONGEAL, A PORTION OF THE PRI-MARY ZONE BEING ADJACENT THE FAR END OF THE MANDREL, PASSING THE SHAPED SILICA THROUGH A SECONDARY ZONE OF CONGELATION WHICH SECONDARY ZONE IS BEYOND THE MANDREL WHEREIN THE SHAPED SILICA IS PERMITTED TO FURTHER COOL AND CONGEAL, AND SUBJECTING THE SHAPED SILICA TO ELONGATION AND LATERAL CONTRACTION IN SAID SECONDARY ZONE UNTIL THE SHAPED SILICA IS WHOLLY CONGEALED.