Abstract: According to the present process for producing a molded glass article, the surface of a lead oxide-containing glass material to be press molded is subjected in advance to an oxidation treatment with activated oxygen ion; thereby, there takes place no reduction reaction of lead oxide at the glass surface, at the time of press molding of the glass material, and there can be obtained a molded glass article with a clear surface. Further, there occurs no adhesion of lead to the surface of the mold used, and consequently the mold life is extended, which is very economical.

Abstract: An image intensifier tube has a faceplate formed of optical material. The outer surface of the faceplate has light receiving and light transmitting surfaces and a layer of a reduced metal oxide material for reducing stray light which is transmitted into the faceplate and reflected off of internal surfaces thereof. The layer has a blackened appearance and is formed by reducing the metal oxide of the faceplate material with hydrogen at a predetermined pressure and temperature to cause the blackening to reach a depth sufficient to reduce transmission of stray light therethrough.

Abstract: For manufacturing a glass article for precision-optical purposes, a preform is provided which is unwrought relating to the desired shape of the glass article to be manufactured and exhibits within the surface areas serving for the formation of optical effective planes a high surface quality. The preform is pressed at a sufficiently high temperature in a mold, the function layers of which, serving for the formation of the optical suitable planes are hard and wear resistant, optionally containing hard nitrides and/or carbides, being mechanically unwrought structureless thin layers coated by cathode sputtering, for example, on a working surface of the basis of the mold. At the beginning of the pressing process, the preform and at least one of the function layers of the mold exhibit a difference in temperature amounting at least to 30 K, but less than a value where inhomogeneities in and/or surface defects on the glass molding may be produced.

Abstract: A method for producing a glass preform for an optical fiber comprising forming a fine glass particle mass by flame hydrolysis of a glass raw material, dehydrating the fine glass particle mass in an oxygen atmosphere containing chlorine or a chlorine-containing compound at such temperature that the soot preform is not considerably shrunk and heating the soot preform at a temperature at which the soot preform is sintered and made transparent, the glass preform produced by which method contains less hydroxyl groups, structural defects and an optical fiber fabricated from said glass preform has stable light transmission characteristics for a long time.

Abstract: A process for the production of a glass by the vacuum melting method using silica as a raw material is disclosed, comprising filing a silica fine powder in a suitable vessel, heating it in the presence of an accelerator for phase conversion to obtain a porous formed body consisting of a cristobalite phase, and then heating and melting the formed body in vacuo. According to the present invention, a transparent and active glass having a high quality can be produced at an inexpensive cost.

Abstract: An improved method of making carbon dioxide and chlorine free fluoride-based glass wherein the atmosphere in the furnace enclosure is sulphur hexafluoride gas at a positive over pressure.

Abstract: A method of vitrifying a porous cylindrical article made out of glass soot, especially for manufacturing a preliminary blank for optical fibers. The article is heat-treated in a furnace in a vacuum or in an atmosphere that contains helium. The porous article is placed in a horizontal graphite tube in the furnace, is sintered therein for 20 to 40 minutes in a vacuum or in a helium atmosphere with reduced pressure at 1250.degree. to 1400.degree. C., and is subsequently vitrified by heat-treating the sintered article at first in the sintering atmosphere, while slowly rotating it in the hot graphite tube for 20 to 40 minutes at approximately 1450.degree. to 1600.degree. C. and then while rotating it in the graphite tube more rapidly than in the first stage for 10 to 30 minutes at approximately 1650.degree. to 1750.degree. C.

Abstract: The potential for fused cast ceramic refractories to release stones into molten material with which it is in contact is reduced by subjecting the refractory to a vacuum pretreatment to remove gases from the glassy phase of the refractory. Preferably the treatment is carried out when the refractory is in a molten state.

Abstract: In an apparatus for molding glass articles, a plurality of processing chambers including a heating chamber, a press chamber and a cooling chamber are arranged in order along a predetermined circular transport path. The processing chambers are surrounded by a case within a furnace body. A rotary table is driven for intermittent rotation about an axis thereof. The transport path extends in concentric relation to the axis of the rotary table. The rotary table extends radially outwardly to a position below the case. A plurality of sample mounts are mounted on the rotary table and are arranged along the transport path in spaced relation to each other. The sample mounts extend into the processing chambers through a slit formed in a bottom wall of the case. A plurality of molds each having accommodated therein a glass preform to be molded are mounted respectively on the sample mounts.

Abstract: In a press-molding device for lenses, an upper surface of a drag is formed into a molding surface, and a lower surface of a cope is formed into a molding surface. An inner peripheral surface of a guide mold portion is in contact with an outer peripheral surface of the drag, and has an axial length longer than that of the outer peripheral surface of the drag so that the inner peripheral surface extends upwardly from the molding surface of the drag. The cope is capable of sliding along the inner peripheral surface. A pressure plate is in contact with an upper surface of the cope before pressing, and is abutted against the upper surface of the guide mold portion by the pressing. A glass preform to be molded is arranged between the molding surfaces of the respective cope and drag. The cope is pressed from above through the pressure plate, thereby molding the glass preform to a lens. The guide mold portion may be divided into a pair of upper and lower portions.

Abstract: The invention relates to techniques for surface deionization of glass under the effect of a corona discharge. The invention consists of treating the object which is movable in relation to the electrodes situated at a short distance from said object which is brought to a high temperature. The treatment is carried out under a continuous current which is regulated in intensity. The treatment is accordance with the invention is preferably applied to sheets of glass during their production.

Abstract: A method of making optical waveguides is disclosed in which, to fabricate a preform, glass forming pulverulent material is filled into a mold by means of one or more screw conveyors. The quantity of glass forming pulverulent material filled into the mold per unit of time is increased by passing a suitable gas through the apparatus. Thus, the quantity conveyed per unit of time can also be controlled by adjusting the gas pressure. By using a dry gas, the moisture content of the powder can be reduced.

Abstract: A high quality fluorophosphate laser glass free from bubbles, inclusions and coloring can be obtained by melting a fluorophosphate glass having a total oxide content of 5 to 30% in terms of cationic %, in a carbon container under a non-oxygen gas atmosphere.

Abstract: A method and apparatus for molding precision optical quality glass elements having complex and concave surfaces requires the apportionment of relative movement between two opposing mold surfaces. First and second molds are contained within a floating alignment sleeve, thereby defining a mold cavity within which an essentially arbitrarily-shaped glass preform is placed. The first mold is moved in the alignment sleeve until stopped by a calibrated standoff. Thereafter, pressing is continued with the second mold moving in the alignment sleeve until opposing surfaces are completely formed at substantially the same time.

Abstract: According to a method of molding a glass body, a glass preform is placed between upper and lower molds of a mold assembly. The mold assembly is then heated to a predetermined heating temperature falling within a heating temperature range corresponding to a glass viscosity range of the glass preform of 10.sup.8 to 10.sup.10.5 poise. A pressure high enough to mold the glass preform is applied between the upper and lower molds when the glass preform is at the predetermined heating temperature, so that an unfinished glass molded body is formed. The pressure is released, and the unfinished glass molded body and the mold assembly are gradually cooled to a temperature within a glass viscosity range of 10.sup.11.5 to 10.sup.14 poise while the unfinished glass molded body is held in the mold assembly. A glass molded body is then released from the mold assembly.

Abstract: There is disclosed an apparatus for producing optical elements, provided with a conveyor for transporting carriers for materials of optical elements into an evacuatable process chamber, and with a heating system for the material supported by the carrier, a forming system for the material supported by the carrier while the material is heated by the heating system, and a system for depositing a thin film to the material formed by the forming system and supported by the carrier.

Abstract: Machine for making pressed glass parts, and particularly cups and stems. A rotatable machine table (4) has several work stations (1) which have one bottom plate (31) each with a means (37) for centering an exchangeably mountable glass mold (3). Each work station (1) has a lift drive for a rod (25) coacting with the glass mold (3). The lift drive contains a first vertical guidance element (8) mounted in the machine table (4). The rod (25) has a second vertical guidance element (20) mounted in the bottom plate (31). Finally, a means for setting the vertical distance between rod (25) and lift drive is provided. To achieve the object of reducing the overall height and weight of the machine, the first vertical guidance element (8) is over its entire length mounted underneath an upper boundary surface (5) of the machine table (4) inside the latter, and the bottom plate (31) is mounted directly on the machine table (4).

Abstract: An adjusting mechanism is disclosed for the press head of a glassware forming machine of the rotating table type having a plurality of forming units circumferentially spaced for rotation about the axis of the machine. Adjustment is effected by rotating a parallel adjusting rod, which is engaged to a threaded rod. Rotation varies the pressure of the plunger by changing the position of a pinion on the threaded rod, through spring compression or pinion gear rotation, to which the stop lever on the plunger steam will contact. Each forming unit is capable of producing at least two glassware articles per machine cycle. A remote ram spring adjustment means provides operator control of ram spring pressure for each plunger at an accessable height and location.

Abstract: A method of forming parisons in machines for making glass bottles which includes introducing a gob of molten glass into a blank mold, moving a cavity plunger to form a parison cavity and subsequently subjecting the gob to a predetermined pressure separate from the cavity plunger to apply pressure urging the molten glass into conformity with the mold.

Abstract: A method wherein the material for manufacturing the fitting is supplied into the mold to the point of intersection of its side channels which are arranged substantially horizontally, and pressing is performed simultaneously in all of the above channels of the mold.

Abstract: The individual section of a Hartford I. S. type machine is modified to permit forming the parisons in an upright orientation, and also for transferring the upright parisons from the blank to the blow side of the section without disturbing this upright orientation. The pressing plungers at the blank station are mounted for movement toward and away from the upwardly open blank mold cavities, and each blank mold cavity is defined in part by partible neck ring molds, in part by a lower solid blank or body mold, and finally by intermediate partible mold sections which engage the upper neck ring molds and also the lower body mold. These intermediate mold sections at the blank side of the machine are mounted on the existing blank mold holder arms.