Abstract: A torch and mount assembly wherein the torch, which has a plurality of gas receiving nipples is carried in a housing through which it extends. The housing has a plurality of walls forming a substantially air tight enclosure. In at least one wall of the housing are one or more leakproof fittings which are connected to similar leakproof fittings for the nipples by means of preferably flexible gas conduits within the housing. In the system, gaseous mixtures are applied from a source or sources to the fittings in the housing wall remote from the high temperatures of the torch, while the conduits within the housing are protected from mechanical and thermal stresses. An inert gas from a suitable source is introduced under pressure into the interior of the housing to reduce leakage from the torch into the housing. The atmosphere within the housing is heated, and the constituents of the housing atmosphere are monitored to aid in detecting leakage.

Abstract: A method for making a glass preform substantially free of OH impurities is disclosed. The method comprises the steps of introducing a moving stream of a vapor mixture including at least one compound glass-forming precursor together with an oxidizing medium into a tube, while generating a hydrogen-free isothermal plasma on an outer surface of the tube to react the mixture and produce a glassy deposit on an inner surface of the tube. The method uses a plasma torch or a radio frequency furnace.

Abstract: The transverse cross section of a body is modified by the steps of: a) determining the extent to which the body has material in excess of a desired shape at a plurality of points, b) exposing the body to a local heat source having a temperature sufficiently high to remove material from the surface of the body, and c) moving the surface of the body in relation to the source at a speed which decreases in regions where the body has material in excess of the desired shape so as to remove more material from such regions than from other regions. In a preferred embodiment, the body is an optical fiber preform, the local heat source is the fireball of a plasma torch, and the body is moved relative to the torch by rotating the preform at a controllable angular velocity while the torch is translated along the length of the preform.

Abstract: To attain high strength optical glass fibers, the glass preforms, from which the fibers are drawn, must generally be free of surface imperfections such as bubbles, and air lines. It has been discovered that these imperfections can be removed quickly and cleanly by contacting the preform surface with a substantial portion of the electrically conducting plasma region (the plasma fireball) extending from a plasma torch. Significantly, the surface material is substantially removed by vaporization, due to the extremely high plasma temperature (>9000.degree. C. at the plasma center) of the isothermal plasma torch. Though the temperatures in the tail of the plasma fireball are substantially less than at the plasma center, the temperatures are generally still several thousand degrees centigrade.

Abstract: The present invention is an externally installed control switch cover assembly to be used with equipment with a ribbed edge and the control switch located adjacent to the ribbed edge. More particularly, the present invention may be used on an IBM-PC computer to cover, protect and lock into position the power switch of the computer.

Abstract: A vapor delivery system for the manufacture of an optical preform includes a deposition bubbler (60) and another bubbler (40) referred to as a supply bubbler which is interposed between a reservoir (24) of a liquid and the deposition bubbler. Heat energy is applied to the supply bubbler and to the deposition bubbler to vaporize liquid therein. A carrier gas is introduced into the liquid in the supply bubbler at a location below the free surface and into the deposition bubbler to cause vapor of the liquid to become entrained in the carrier gas and to flow from the supply bubbler into the deposition bubbler and from the deposition bubbler to a substrate tube from which an optical preform is made. Facilities are provided for maintaining sufficient liquid in the supply bubbler and suitable temperatures of the liquid in the supply and deposition bubblers to control the vapor flow into and out of the deposition bubbler to prevent unintended perturbations in the deposition bubbler.

Abstract: An open end (61) of a tube (62) is disposed below a free surface of a treating solution (60) which is capable of reacting with a liquid effluent to provide a disposable reaction product. A pressurized gas which is non-reactive with the effluent and with the treating solution causes the effluent to be moved through the tube and discharged into contact with the treating solution. Also, the gas is flowed through a shroud (63) disposed concentrically about the tube. The gas envelops the effluent and the shroud prevents contact of the treating material with the effluent and the gas along a predetermined distance beyond the open end of the tube. This arrangement causes the treating material to react with the effluent at a location spaced from the end of the tube thereby preventing clogging of the tube. The discharge of the gas along with the liquid effluent into the treating solution causes a substantial mixing of the two liquids to provide a substantially complete reaction.

Abstract: A sealed rotary joint and method are described wherein a purge fluid is passed over a tube rotating within an end cap and through a ball bearing component of the joint.

Abstract: A lightguide fiber preform is made by depositing optically suitable layers of doped silicon dioxide on an inner wall of a rotating glass substrate tube (31) which is exposed to a moving zone of heat during a deposition mode and during a mode when the tube is collapsed. During each of a plurality of passes of a torch assembly (50) in the collapse mode following deposition, a contact device (101) is in continuous engagement with the tube and is caused to apply forces to each successive increment of its length following exposure to at least an initial portion of the zone of heat to collapse incrementally the tube. Between successive ones of the plurality of passes, the contact device is moved inwardly of the tube so that each increment of length is exposed to forces which as between the successive passes are applied at points incrementally closer to the longitudinal axis (36) of the tube.

Abstract: A preform from which lightguide fiber is drawn is made by depositing optically suitable layers of doped silicon dioxide on an inner wall of a rotating glass substrate tube which is exposed to a moving zone of heat during a deposition mode and during a collapse mode. During at least a first pass following the deposition mode, a contact device is caused to engage each successive increment of length of the tube during exposure to the zone of heat. The contact device causes any sagged or offset portions of the tube to be reconfigured and causes the tube to have a central longitudinal axis which is a straight line which extends between stocks of a lathe by which ends of the tube are supported. The contact device may also be used to cause the tube to have a predetermined configuration along its length.

Abstract: A glass tube is formed having a mean cross-sectional tube wall area less than a preselected mean cross-sectional area. Additional glass differing in composition from that of the glass tube, but having an index of refraction substantially equal to that of the glass tube, is then fused onto a surface of the tube by vapor deposition, outside vapor-phase oxidation or outside vapor-phase axial deposition until the tube wall obtains the preselected mean cross-sectional area.

Abstract: Apparatus for supplying fluid to a rotary tube uncontaminated with ambient air comprises an end cap having an open ended bore in which an end portion of the tube may be rotatably positioned, a first conduit extending into the end cap through which fluid may be fed into the rotary tube, and a second conduit communicating with the end cap bore through which a purge fluid may be fed into and at least partially through the bore to the exterior of the end cap.

Abstract: A sealed rotary joint and method are described wherein a purge fluid is passed over a tube rotating within an end cap and through a ball bearing component of the joint. A vapor stream including a vaporized glass forming precursor entrained in an oxidizing carrier gas is passed into a rotating optical fiber preform tube through a housing supporting the ball bearing. A stream of the oxidizing carrier gas at a pressure greater than the pressure of the vapor stream can act as the purge fluid.

Abstract: A method of introducing a vapor stream into a rotating optical fiber preform tube comprising the steps of: (a) generating a vapor stream comprised of a vaporized glass forming precursor entrained in an oxidizing carrier gas; (b) flowing the vapor stream into the rotating optical fiber preform tube through a sealed rotary joint; and (c) preventing any material alteration in the composition of the vapor stream from occurring should the sealed rotary joint become leaky by flowing a stream of fluid consisting essentially of the oxidizing carrier gas over the rotary joint at a pressure greater than the pressure of the vapor stream as it flows through the rotary joint.

Abstract: Methods and apparatuses are disclosed for exhausting reaction products from an optical fiber preform tube and for choking off the preform tube during collapse wherein an exhaust tube (40) is provided with an entry end (41) located adjacent and in fluid communication with a downstream end (10') of a preform tube (10), suction applied to the exhaust tube (40), and a stream of reaction product agitating gas free of reaction products introduced into the exhaust tube (40) at a location adjacent the exhaust tube entry end (41).

Abstract: A method is disclosed for controlling the delivery of vapor from a bubbler containing a supply of liquid through which a carrier gas is bubbled and from which bubbler vapor is delivered in a vapor stream entrained with the carrier gas. The method comprises the steps of sensing the ratio of vapor to carrier gas in the vapor stream and applying heat to the liquid within the bubbler at rates relative to the sensed ratios of vapor to carrier gas being delivered from the bubbler in a vapor stream to hold the ratio constant.A vapor delivery control system is also disclosed which comprises a vaporizer, a heater thermally coupled with the vaporizer, and means for maintaining a supply of liquid in the vaporizer.

Abstract: A vapor delivery system is disclosed comprising a bubbler 12 is adapted to generate and deliver vapors from a vaporizable liquid contained therein, and a reservoir 30 in fluid communication with the bubbler 12 from which liquid may be continuously fed into the bubbler to replenish liquid vaporized within and withdrawn from the bubbler. The system further comprises means for sensing the level of vaporizable liquid in the bubbler and means for providing a gaseous head pressure in the reservoir of variable magnitude dependent upon the level of vaporizable liquid sensed by the sensing means to maintain the level of liquid in the bubbler substantially constant.

Abstract: In order to react gases and/or vapors to deposit optically suitable layers of doped silicon dioxide on an inner wall of a glass substrate tube to produce a preform from which optical fibers are drawn, the glass tube is heated by a mixture of combustible gases. The combustible gases are directed along passageways in a housing of a torch assembly which confines a portion of the length of the tube and then out of the passageways to produce a flame that engages the confined portion of the length of the tube. The housing and walls that define ends of the passageways adjacent the tube are cooled to an extent which substantially eliminates oxidation of the material from which the housing and the walls of the passageways are constructed.

Abstract: A system for generating and delivering vapors to a vapor deposition station is disclosed which comprises a bubbler 10 adapted to contain a supply of liquid, a bubbler heater 14 thermally coupled with the bubbler and electrically coupled with a heater controller, a temperature controlled chamber 23 located above the bubbler, and means 58,59 for heating the space within the temperature controlled chamber. A carrier gas intake conduit 27,28 extends through the temperature controlled chamber and down into the bubbler through which carrier gas may be introduced into the bubbler. A vapor exhaust conduit 41,49 extends upwardly from the bubbler and through the temperature controlled chamber through which vapors may be carried from the bubbler entrained with the carrier gas to the vapor deposition station. A sensor 52 is positioned within that portion of the vapor exhaust conduit located within the temperature controlled chamber and operatively coupled with the bubbler heater controller.

Abstract: A device (80) for sealing a furnace (50) which is used to draw a fiber (52) from a rod-like preform (51) includes a housing (82) having a cavity (121) for receiving a disc (111). The disc (111) is suspended for movement in the cavity in a plane lateral to the preform that extends through a center opening (116) in the disc and into the furnace. An inert gas is supplied to the cavity and directed inwardly through radially disposed passageways (118--118) in the disc (111) to impinge on the preform and split into two streams which move along the preform in opposite directions to prevent the entry of ambient air into, as well as the escape of gas from within, the furnace. The inert gas also causes the disc to be moved within the cavity to compensate for irregularities in the preform or for its misalignment from a vertical axis of the furnace, and provides a cushion so that contact between the disc and the preform is avoided.