Abstract: An improved method of forming porous glass preforms by generating glass particles from a vapor phase and applying the particles onto a substrate characterized by generating the glass particles from a vapor phase in a separate operation, collecting the particles and then subsequently applying the previously collected particles onto a deposition surface of the substrate by creating a hot zone adjacent the deposition surface and projecting the particles as a stream through the hot zone and onto the deposition surface.

Abstract: A method for producing a bare fiber taper at a metallized fiber is disclosed and comprises the steps of softening and drawing in an arc of the fiber metallized by sputtering or vapor deposition. The softened metallized fiber thereby constricts and the metallized fiber becomes free of the metallization and, thus, bare over its entire circumference in the arising constriction as a consequence of the influence of the arc. The bare constriction produced in such fashion is parted and a tapering, bare end section thereby arising at one of the two metallized fiber halves produced by the parting can be employed as the bare fiber taper. A fiber taper with lens can be produced by fusing a lens to the bare end section.

Abstract: This disclosure describes a novel method of coating a substrate, e.g., a transparent glass substrate, with a very thin inorganic coating of predetermined varying composition, e.g. an electrically-conductive tin oxide coating. The coating is carried out in such a way that quality control problems associated with leakage of the coating reactants from the reaction zone are virtually eliminated. The resulting coating can exhibit excellent non-iridescent properties even at thicknesses well below on micrometer.

Abstract: A heat shield for the refractory tube in a molten glass feeder has an annular metal shell with semi-circular insulating segments stacked therein. The shell is made in half sections to permit easy removal and the segments are provided in sets with relieved areas to accommodate the reciprocating refractory plungers.

Abstract: Method and device manufactured thereby for economically making solar collectors and concentrators by employing a technique of applying high-efficiency, energy absorptive coatings. The technique is spraying less-than-ultra-pure nickel or chromium, in a molten state, onto a heated surface of a glass absorber substrate so that a thin metallic layer fuses thereon. After spraying, the metallic layer is chemically blackened. An outer glass insulator jacket is hermetically sealed, using a glass-to-glass junction, over the inner glass absorber substrate to provide an insulating space. The spraying technique employed is more economical than by applying the metallic coating by conventional vapor deposition and sputtering techniques which require expensive equipment and ultra-pure metals. Absorption efficiency exceeding 95% with infrared emissions below 0.09% has been achieved. Borosilicate glass is preferred, but other transparent substances can also be used.

Abstract: A multiple gob glass feeder system has a conventional feeder bowl with an outlet spout in which a triple or quadruple orifice plate is provided to deliver a plurality of uniform, molten glass gobs. The feeder has two plungers mounted pivotally in the support base, which are angularly and symmetrically adjusted, by a mechanism of angular adjustment, coupled between said plungers, in order to graduate the position of said plungers, according to three or four discharge orifices in the orifice plate.

Abstract: An optical fiber which has just been drawn from an optical preform is provided with an external hermetic coating by using a heterogeneous nucleation thermochemical deposition technique. This technique involves passing the fiber through a reaction zone which contains a gaseous medium that includes a reactant which decomposes, or a mixture of reactants which chemically react, at a predetermined temperature to form the material of the coating. Only the fiber but not the gaseous medium surrounding the same is heated to the predetermined temperature, especially by directing radiation onto the exposed circumferential surface of the fiber, so that the decomposition or the chemical reaction takes place directly on the exposed surface of the fiber rather than in the gaseous medium, accompanied by simultaneous deposition of the coating material on the exposed surface of the fiber. The resulting fiber with hermetic coating can then be provided with an additional polymer coating layer.

Abstract: A method of coupling at least a pair of optical fibers together assures predictable coupling ratios and structural integrity. First, the fibers are prepared by coating or dispersing a material (e.g., a metal oxide) on or in them to control the surface tension of their exposed surfaces so that fusion occurs within predictable, extended periods of time. Next, the fibers are twisted together to assume a mutually helical relationship and to apply a small tensional stress on them and they are placed in an inert gas maintained at a predetermined pressure. A coaxially disposed tungsten coil heats them and fuses the twisted, stretched fibers together to effect a desired coupling. Stretching the twisted fibers as they are being fused together creates uniform tapered sections which are needed to induce proper coupling. The rate of heating and fusing, the inert gas and its pressure, and the force exerted during stretching are all factors determinative of the degree of coupling.

Abstract: In glass gob forming apparatus which includes one or more reciprocatable plungers each mounted above a respective orifice in the floor of a refractory trough such that on axial reciprocation of the plungers in use molten glass is forced in the form of gobs through the orifice, the plungers being surrounded by a refractory cylinder, there is provided a refractory heat insulating body within the cylinder around the plungers.

Abstract: Glass fibers employed as optical waveguides are provided with a metal coating by passing the glass fiber, following its formation, through a chamber into which a metal-containing compound is introduced. A source of radiant energy, e.g., a CO.sub.2 laser, is introduced by means that are controllably positioned from the glass fiber, e.g., an infrared-transmitting fiber such as thallium bromo-iodide. The radiant energy is sufficient to cause dissociation of the metal-containing compound on the glass fiber surface so as to form the metal coating on the glass fiber without coating the rest of the apparatus. Any metal compound may be used such as metal carbonyls, metal halides, metal alkyls, metal aryls, metal olefins, metal esters, metal nitro compounds, metal hydrides and combinations and mixtures thereof.

Abstract: An improved glass melt tank (10) having a feeder (15) and a channel (14) which interconnects the tank and the feeder and in which is arranged a rotary, raisable and lowerable regulator (20, 21) which opens and closes the channel (14) so that the feeder (15) is supplied with molten glass from the tank (10) when a level sensing means (22) senses a lower level in the feeder, the supply of molten glass being caused to cease when an upper level is sensed. The regulator (20, 21) rotates continuously in order not to get stuck in setting glass and seals against a horizontal seat formed in the channel.