Abstract: Insertion of a lightguide preform (12) into a tube (14) without contacting the sides thereof is accomplished by first roughly aligning the rod in spaced axial alignment with the tube. Thereafter, the offset of the rod from the axis of the tube is measured and the amount of lateral movement of the rod from the axis is determined. Then the rod is moved laterally in accordance with the determined amount of movement to precisely align the rod with the tube. Once alignment has been achieved, the rod is inserted in the tube and the tube is collapsed thereabout. An apparatus (10) for practicing this method is disclosed.

Abstract: This disclosure is directed to an oxy-hydrogen torch (10) comprised of a plate (16) captured between first and second outer members (12 and 14). Each outer member has a plenum (18) which open towards, and is separated by, the plate (16). The plate (16) has a plurality of groups (29, 30, 31) of spaced grooves (32--32) in one major surface (34). The groups of grooves (32--32) are arranged in an interleaved relationship with groups (29', 30', 31') of spaced grooves (36--36) on the opposite surface (38). The grooves (32 and 36) extend from one surface 46 of the plate (16) to the respective plenums (18--18) in the outer members (12 and 14). Each of the grooves (32 and 36) in a group are radially directed at a different point. Oxygen is directed into one plenum (18) and hydrogen urged into the other plenum. The gases pass through the respective grooves (32 and 36) to the surface (46) of the torch (10) for mixing and ignition.

Abstract: A fused silica glass tube (26) is extruded from a melt (21) in a chamber (11) pressurized with an inert gas. A shield is placed in close, spaced, relation to the melt (21) surface during the gas pressure extrusion process to substantially eliminate losses from the melt due to vaporization.

Abstract: A gas head extrusion apparatus (10), having upper (12) and lower (13) chambers, is arranged to feed glass particulate (60) into the upper chamber (12). The particulate (60) is heated to consolidate the particulate (60) into a first viscous melt (71) as an elevated gas pressure is simultaneously applied within the chamber (12). The first viscous melt (71) is urged through a narrow opening (16) in the bottom (14) of the upper chamber (12) into the lower chamber (13) to form a second viscous melt (73). The lower chamber (13) is pressurized to a second pressure, P.sub.2, where P.sub.1 >P.sub.2. Gas bubbles, having an internal pressure, P.sub.1, formed during the consolidation process in the upper chamber (12), will expand in the lower chamber (13) to facilitate removal thereof from the melt (73). The lower pressure, P.sub.