Abstract: In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate VC, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate VT. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of VC and VT:VT=VC±0.2·VC.

Abstract: A method for manufacturing an optical preform including the steps of providing a substrate tube having deposited layers of glass on an inside surface thereof, increasing an outer diameter of the substrate tube by means of applying a traversing heat source to heat the substrate tube to above a softening temperature thereof and by providing an internal pressure in the substrate tube higher than an ambient pressure, and collapsing the substrate tube of increased outer diameter by means of applying the traversing heat source to heat the substrate tube to above the softening temperature thereof such that an optical preform is manufactured.

Abstract: A container extends along a longitudinal axis and includes a base, a body extending axially from the base, and a generally radially outwardly facing external surface having sharply outlined indicia. The indicia includes generally V-shaped depressions having outer slopes, inner slopes, and vertices connecting the slopes. A method of making the container is also disclosed.

Abstract: A device for forming a hollow glass article from a parison is provided. The hollow glass article includes a ring extending around an axis, a body and at least one shoulder extending between the ring and body. The device includes a mold including a plurality of portions movable between a closed configuration and an open configuration. The closed configuration defines a first imprint for forming the body of the article. The device also includes a blowing head movable between a blowing position and a rest position. In the blowing position, the blowing head injects at least one gas jet into an inside of the parison. The blowing head includes at least one face defining a second imprint for forming at least one portion of the at least one shoulder in the blowing position. A method and hollow glass article are also provided.

Abstract: A facility for manufacturing a hollow glass article, including: a finishing mold intended to receive a blank of the hollow glass article and defining a cavity for forming the hollow glass article, at least one gas source, and a blowing head connected to the gas source and adapted for achieving at least one injection of the gas into the inside of the blank contained in the cavity. The facility further includes: at least one reservoir of coloring powder, and a system for injecting the coloring powder into the inside of the blank while the blank is located in the finishing mold and into the inside of the hollow glass article while the hollow glass article is located in the finishing mold, so that the injection of the coloring powder takes place before, during, after, before and during, during and after, or before, during and after the gas injection.

Abstract: An optical microresonator is configured as an optical microbubble formed along a section of an optical microcapillary. The curvature of the outer surface of the microbubble creates an optical resonator with a geometry that encourages the circulating WGMs to remain confined in the central region of the bubble, creating a high Q optical resonator. The resonator may be tuned by modifying the physical properties of the microbubble, allowing the resonator to be used as an optical filter. The resonator may also be used as a sensor or laser by introducing the material to be sensed (or the active laser material) into the microcapillary along which the microbubble is formed.

Abstract: A bottle of one-piece integrally formed construction has a body with a closed base and a shoulder at an end of the body remote from the base, and a neck extending from the shoulder along an axis and terminating in a neck finish for attachment of a closure. The bottle neck includes at least one internal embossment for affecting flow of liquid from the body through the neck. In exemplary embodiments of the disclosure, the at least one internal embossment includes at least one internal annular rib or at least one internal rib coplanar with the neck axis or at least one internal spiral rib or at least one internal elliptical rib.

Abstract: An I.S. Machine is provided wherein the blow molds are closed to a slightly cracked location whereby applied cooling air can not leak into and pressurize the blow mold thereby damaging the parison during reheat. When reheat is completed, the blow molds are fully closed and the parison is transformed into a bottle by applying compressed air and/or vacuum.

Abstract: An I.S. Machine is provided wherein the blow molds are closed to a slightly cracked location whereby applied cooling air can not leak into and pressurize the blow mold thereby damaging the parison during reheat. When reheat is completed, the blow molds are fully closed and the parison is transformed into a bottle by applying compressed air and/or vacuum.

Abstract: A manufacturing method of a double spiral glass tube having a bump that is difficult to break. The manufacturing method includes the steps of: causing the bump forming section (32) in the central portion (13) to have greater tube thickness than the other sections in the glass tube (23) that has been deformed into a double spiral shape; heating and softening part of the bump forming section; and forming a bump (14) by injecting a nitrogen gas (27) into the inner space of the glass tube from both ends thereof to expand the bump forming section. With this structure, the bump forming section is preliminarily formed to have a greater tube thickness than the other sections. As a result, the bump, which is formed by expanding the bump forming section to have a smaller tube thickness than before the expansion, still maintains a sufficient strength.

Abstract: A blow head mechanism for an I.S. machine wherein the blow head has a final blow tube. The final blow tube is supported for vertical displacement between an up position where the open end of the final blow tube is proximate the top of a blown parison and a down position where the open end of the final blow tube is proximate the bottom of a blown parison. The final blow tube is oscillated a plurality of times during the time when the blow head is “on.

Abstract: Disclosed is a method for producing single microlenses or an arrays of microlenses composed of a glass-type material, in which method a first substrate is provided with a surface containing impressions over which a second substrate composed of a glass-type material is placed at least partially overlapping it and is joined therewith under vacuum conditions. The substrate composite is tempered in such a manner that the second substrate softens and flows into the impressions of the first substrate, thereby structuring the side of the second substrate facing away from the first substrate in order to form at least one microlens surface.

Abstract: Disclosed is a method for producing single microlenses or an arrays of microlenses composed of a glass-type material, in which method a first substrate is provided with a surface containing impressions over which a second substrate composed of a glass-type material is placed at least partially overlapping it and is joined therewith under vacuum conditions. The substrate composite is tempered in such a manner that the second substrate softens and flows into the impressions of the first substrate, thereby structuring the side of the second substrate facing away from the first substrate in order to form at least one microlens surface.

Abstract: The manufacturing method comprises: a softening step of softening a straight glass tube in a heating furnace; a moving and placing step of moving the softened glass tube so that the glass tube is placed on the top of the mandrel; and a winding step of winding the glass tube placed on the top of the mandrel around the periphery of the mandrel. The mandrel is disposed beneath the glass tube starting to get soft, and the glass tube being soft is perpendicularly lowered in order to be placed on the top of the mandrel. In the winding step, the winding speed Vr at which the glass tube is wound around the mandrel is higher than the moving speed Vs at which chuck units holding the ends of the glass tube move toward the mandrel.

Abstract: The invention relates to a method for shaping a tubular object made of glass or glass ceramics or any other thermoplastic material, comprising the following method steps: the object is heated up to softening; an inner shaping tool and an outer shaping tool are provided for shaping The outside and inside jacket surface of the object, of which at least the inner shaping tool consists at least in the region of its shaping surface of open-pored material with a permeability of between 10?11 and 10?16 m2; a free-flowing pressurized medium is conducted through the open-pored material towards the surface of the object to be shaped; the inner shaping tool is introduced into the object; the outer shaping tool is applied on to the object in order to shape the same

Abstract: Stress exerted on an inner or outer circumferential side of a glass tube 6 is controlled when a glass material 3 is heated and softened by a heating element 41 provided around the glass material 3 and a piercing plug 31 is relatively pressed into a softened region of the glass material 3 to thereby form the glass material 3 into the glass tube 6 gradually. For example, the control of the stress can be carried out by controlling an internal or external pressure of the glass tube 6. As a result, the deformation of the glass tube 6 just after piercing is prevented so that the glass tube 6 can be obtained with high quality. It is also possible to solve the problem that cracks may occur easily at the time of reheating because of residual stress distribution after cooling.

Abstract: There is disclosed a method for forming a discharge tube for a low-pressure discharge lamp. In the method, an end of a section of the discharge tube is fastened with first clamping means, and a second end of the section in held in an oriented position. The section is heated to a softening temperature, and a bending moment is exerted on the section between the first end and the second end for achieving the desired radius or direction of curvature of the section. The holding of the second end of the section and the exertion of the bending moment on the section are effected at least partly with another re-solidified section of the discharge tube which is adjacent to the softened first section. An apparatus for performing the method is also disclosed. The apparatus comprises first and second clamping means for positioning the ends of a bending section of the discharge tube in an oriented position relative to each other, and for exerting a bending moment on the ends.

Abstract: A method of making a capillary splice includes applying pressure to a bore in a tube, applying heat to a portion of the tube to soften the portion of the tube, and forming a bubble within the bore in the heated portion under the influence of the pressure and heat. While forming the bubble, a diameter of the bore at the heated portion is measured to determine when the bubble has enlarged to a target size. When the bubble has enlarged to the target size, a force is applied along an axial axis of the tube to shape the bubble to a desired size.

Abstract: The manufacturing method comprises: a softening step of softening a straight glass tube in a heating furnace; a moving and placing step of moving the softened glass tube so that the glass tube is placed on the top of the mandrel; and a winding step of winding the glass tube placed on the top of the mandrel around the periphery of the mandrel. The mandrel is disposed beneath the glass tube starting to get soft, and the glass tube being soft is perpendicularly lowered in order to be placed on the top of the mandrel. In the winding step, the winding speed Vr at which the glass tube is wound around the mandrel is higher than the moving speed Vs at which chuck units holding the ends of the glass tube move toward the mandrel.

Abstract: There are provided a method of manufacturing a glass part for connecting optical fibers, which allows insertion of optical fibers into the internal hole of the glass part smoothly, and glass parts for connecting optical fibers manufactured using the method. Predetermined parts of a glass tube having an internal hole are heated while pressure is applied into the internal hole, to expand the predetermined parts, thus forming tapered portions. As a result, a continuous curved surface can be achieved at the boundary between each tapered portion of each obtained glass part and the internal hole thereof, and the surface can be made smooth where the tapers are formed.

Abstract: In order to avoid deposition of evaporating alkali compounds on an inner surface of a hollow glass body during thermal processing to form a glass container from the hollow glass body, an overpressure is provided in the hollow glass body during the thermal processing. Either rinsing the hollow glass body with a gas, such as air, or at least partially closing the glass body at one end so that sufficiently rapid pressure equilibration is avoided, can provide this overpressure. The glass containers made by these methods are especially suited for food or pharmaceuticals because they have a reduced alkali release from their inner surfaces, for example at most about 2.0 mg/l sodium oxide.

Abstract: A process for manufacture of a component made of opaque synthetic quartz glass, and a quartz glass tube manufactured according to said process. The process comprises (i) providing a starting material in the form of granulated material of highly pure, synthetic SiO2 comprising at least partially porous agglomerates of SiO2 primary particles, the granulated material having a compacted bulk density of no less than 0.8 g/cm3, (ii) filling the granulated material into a mold and converting it to an opaque quartz glass preform through a process of melting, and (iii) reshaping the preform in a heat reshaping process to obtain a component made of opaque quartz glass. A quartz glass tube is made of quartz glass consisting of a granulated material of synthetic SiO2 with a lithium content of no more than 100 wt-ppb, and the wall thickness of said component being in the range of 0.5 mm to 15 mm.

Abstract: A method of making a capillary splice includes applying pressure to a bore in a tube, applying heat to a portion of the tube to soften the portion of the tube, and forming a bubble within the bore in the heated portion under the influence of the pressure and heat. While forming the bubble, a diameter of the bore at the heated portion is measured to determine when the bubble has enlarged to a target size. When the bubble has enlarged to the target size, a force is applied along an axial axis of the tube to shape the bubble to a desired size.

Abstract: A manual glass lathe used for shaping and coloring clear glass tubes. The manual glass lathe, in the preferred embodiment, comprises a tubular handle, designed to be held in one hand, and a thumbwheel located towards the working end of the handle, and is used by a glass-blower to precisely control the spin of a glass workpiece and the proximity of the workpiece to a flame and to various shaping tools and/or fuming rods. The handle makes use of an interior arrangement of bearings and o-rings to center and hold the mandrel, and also comprises an inner sleeve used as an inertial weight to enhance spinning momentum. Also a method for using such a manual glass lathe to shape and fume glass workpieces.

Abstract: The present invention relates to a method for producing a glass body with at least one inner tube which is closed off on one side and one outer tube which is closed off at least on one side, with the inner tube being connected not coaxially with the floor of the outer tube and the inner tube comprising an opening, with the inner tube being fixed in the outer tube in such a way that the outer tube comprises a projecting portion, a floor is formed by the projecting portion on the outer tube, an opening is formed by the removal of the glass on the inner tube, and the outer tube is evacuated at the end and molten off.

Abstract: A method for manufacturing a glass tube used for a fluorescent lamp having an arc tube constructed by joining a plurality of glass tubes is provided. According to this method, a straight glass tube held at both ends is rotated, and a predetermined cutting portion of the glass tube is softened by heating, and then the glass tube is moved in the heated state in the direction toward the predetermined cutting portion to form a glass accumulated portion at the area of the predetermined cutting portion. Next, the glass tube is drawn away in the direction receding from the predetermined cutting portion, and the predetermined cutting portion of the glass tube is cut into two glass tubes having self-closing end walls. In this way, the end walls of the self-closed glass tubes can be formed thicker and more uniform compared to those obtained by the conventional techniques, and the mechanical strength of the end walls also can be improved.

Abstract: A pair of chucks, which grip end portions of a cylindrical glass tube blank, are moved by a chuck moving mechanism toward each other, so that softened glass in an intermediate portion of the cylindrical glass tube blank is gathered, thereby forming a shape that is suitable for blow molding a light emitting tube portion. In the approaching movement, the position of one chuck is detected by using a laser position detector, and a result of the detection is fed back to the chuck moving mechanism, so as to control the approach distances of the chucks. The laser position detector detects the position of the chuck itself. Therefore, even when the positional relationship between the chuck and the chuck moving mechanism is varied, or backlash or deformation occurs in the chuck moving mechanism, the correct position of the chuck still is detected irrespective of such variation, backlash or deformation.

Abstract: A method of making an optical device comprises the steps of providing a body of vitreous material that is generally tubular along an axis. A portion of the body is molded with external mold structure for forming a bulbous portion when the interior of the tube is pressurized. An axial portion is cut from the bulbous portion to form a first coupling device with first and second axially oriented openings. This method can produce optical coupling devices with excellent optical quality in an economical manner.

Abstract: There is disclosed a method for forming a discharge tube for a low-pressure discharge lamp. In the method, an end of a section of the discharge tube is fastened with first clamping means, and a second end of the section in held in an oriented position. The section is heated to a softening temperature, and a bending moment is exerted on the section between the first end and the second end for achieving the desired radius or direction of curvature of the section. The holding of the second end of the section and the exertion of the bending moment on the section are effected at least partly with another re-solidified section of the discharge tube which is adjacent to the softened first section. An apparatus for performing the method is also disclosed. The apparatus comprises first and second clamping means for positioning the ends of a bending section of the discharge tube in an oriented position relative to each other, and for exerting a bending moment on the ends.

Abstract: A mold for shaping the end region and the opening at a selected end of a first, hollow, generally cylindrical, glass tube to enable a second tube, of smaller diameter than the first tube, to be inserted snuggly a first distance within the selected end of the first tube resulting in the two tubes nesting and being self-centered. The mold includes two complementary elongated side pieces having inner side surfaces for, when joined, encircling the periphery of the first tube along a given portion of its selected end region, and an end cap with a cylindrical stub for insertion within the opening of the first tube at its selected end.

Abstract: A pressure pad array is used to float glass sheets from a glass heating furnace to a ring mold in a press bending station. The pressure pads have transversely spaced, longitudinally-extending slotted nozzles angled towards one another to provide a static pressure area for floating the glass sheet. The slotted nozzles are aligned with the direction of glass sheet travel and the space between adjacent pressure pads is covered by a spacer baffle to generate additional static pressure flotation areas. The static pressure areas formed by the slotted nozzles generally produce uniform pressure profiles extending longitudinally and transversely against the sheet's underside to stably float the glass sheets on a heated gas cushion.

Abstract: A device and process for forming hollow glassware comprising producing solid glass blanks in a manufacturing line, storing the blanks, feeding the blanks to a manufacturing line for forming hollow glassware, preheating the blanks during the feeding step, supplying the preheated blanks to a heating stage, heating to form solid plastically deformable glass globs, transferring the glass gobs to a blow molding stage and blow molding the glass gobs supported by a bottom lifter in a blow mold.

Abstract: Silica grain of desired properties and size is created in a vacuum chamber. Fine silica powder is injected in the chamber or silica powder is formed in situ by combusting precursors. A plasma is formed centrally in the chamber to soften the silica powders so that they stick together and form larger grains of desired size. The grains are collected, doped, fused and flowed into tubes or rods. A puller pulls the tube or rod through a chamber seal into a lower connected vacuum chamber. The tube or rod is converted to rods and fibers or plates and bars in the connected chamber. Fused silica in a crucible tray is subjected to ultrasound or other oscillations for outgassing. Gases are removed by closely positioned vacuum ports.

Abstract: There are provided a method of manufacturing a glass part for connecting optical fibers, which allows insertion of optical fibers into the internal hole of the glass part smoothly, and glass parts for connecting optical fibers manufactured using the method. Predetermined parts of a glass tube having an internal hole are heated while pressure is applied into the internal hole, to expand the predetermined parts, thus forming tapered portions. As a result, a continuous curved surface can be achieved at the boundary between each tapered portion of each obtained glass part and the internal hole thereof, and the surface can be made smooth where the tapers are formed.

Abstract: An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn.

Abstract: The present invention is directed to a method for forming glass articles containing enclosed channels. The method comprises the following steps: a) delivering and depositing a first length of a molten glass ribbon (18) to a surface of a mold (20) having a mold cavity (22) possessing at least one channel-forming groove (22) and a peripheral surface, wherein the first length (18) overlies the mold cavity (22) and the peripheral surface; b) allowing the first length of the molten glass ribbon (18) to substantially conform to the contour of the mold cavity (22) resulting in the formation of at least one channel in the first length of the molten glass ribbon (18); c) delivering and depositing a second length of the molten glass ribbon (26) to the exposed surface of the first length of the molten glass ribbon (18).

Abstract: A method for manufacturing a glass tube used for a fluorescent lamp having an arc tube constructed by joining a plurality of glass tubes is provided. According to this method, a straight glass tube held at both ends is rotated, and a predetermined cutting portion of the glass tube is softened by heating, and then the glass tube is moved in the heated state in the direction toward the predetermined cutting portion to form a glass accumulated portion at the area of the predetermined cutting portion. Next, the glass tube is drawn away in the direction receding from the predetermined cutting portion, and the predetermined cutting portion of the glass tube is cut into two glass tubes having self-closing end walls. In this way, the end walls of the self-closed glass tubes can be formed thicker and more uniform compared to those obtained by the conventional techniques, and the mechanical strength of the end walls also can be improved.

Abstract: In a method for manufacturing a fluorescent lamp, four dual tubes that are previously manufactured are held at a distance in such a manner that the dual tubes can move horizontally. Four portions for connection are simultaneously heated, and two of the dual tubes are simultaneously moved horizontally to form bridge portions to provide tube assemblies. Furthermore, annealing after bridge connection and the connection of tube assemblies with a bridge are performed simultaneously. Thus, a compact fluorescent lamp comprising eight glass tubes that are connected with bridges to form continuous discharge paths can be obtained. According to the manufacturing method, bridge connection can be performed in a small space and with high productivity, and a fluorescent lamp having a good quality with minor variations in the quality of the bridge portions can be provided.

Abstract: An apparatus for applying heat to a rotatable workpiece is disclosed. A rotating lathe is provided for mounting a workpiece, for example a quartz tube, thereto so as to enable rotation of the workpiece. At least one translatable burner is coupled to a fuel source and an oxygen source for producing a flame. The burner is directed such that flame impinges upon the workpiece mounted on the rotating lathe. A first pulse control valve is coupled to and positioned between the translatable burner and the fuel source. A second pulse control valve is coupled to and positioned between the translatable burners and the oxygen course. The first and second pulse control valves are pulsed at a predetermined frequency to prevent the formation of a steady thermal boundary layer about the workpiece to improve the rate of heat transfer between the flame and the workpiece.

Abstract: To provide a halogen incandescent bulb with controlled variation in wall ckness of the bulb, a bulb tube (20) first has a cup region (26) formed thereon. The cup region, by radial application of force, for example by rollers (22), is constricted, and the constriction then pulled to form a small, closed projecting tip (19). Mold jaws (27) then mold the shape of the bulb; the mold jaws are formed with a cavity (29') to receive the projecting tip (19) which, then, has the end cut off to provide an attachment cannula (30) for the pumping tube (32). The pumping tube is melted on the nipple (29) of the cup (26) of the bulb. A filament mount (8) with filaments (9) is then introduced, and pinch jaws (35) pinch-seal the filament mount in the bulb and finish-shape the bulb. The bulb can then be flushed, evacuated, and filled with the requisite halogen containing fill through the pumping tube (32), which then is tipped off.

Abstract: The present invention is directed to a method for forming glass articles containing internal enclosed channels.

Abstract: Two arc tubes which are to be connected are held at different levels. Predetermined portions in the vicinity of an end of each arc tube are evenly heated and softened by a flame of a burner from the side. An air flow is supplied to blowing up the softened portion to form a semi-junction bridge having a circular cross-section and a flat connecting face. The thickness of the wall of the semi-junction bridge is even. The arc tubes having the semi-junction bridges are disposed on the same plane and one arc tube is moved to the other to connect the semi-junction bridges while the connecting faces are softened.

Abstract: A glass substrate is positioned between a chamber with a reduced pressure and a chamber filled with a heated helium, and the glass substrate is forcibly bent by the pressure difference and the heated helium gas into a uniform shape. The irradiation of laser light is carried out in this state to compensate the difference of annealing effects due to fine difference of deformation of the respective glass substrates.

Abstract: A solid workpiece, e.g. a glass tube, is shaped by a focussed beam of visible light or light in an adjacent portion of the electromagnetic spectrum in a material removal, cutting or drilling operation and is heat-treated or remelted or shaped in a plastic state by heating that second beam which is less focussed or even divergent. The beams derive from a common source, a CO.sub.2 laser, and pass through a splitting deflecting system so that the beams can be directed simultaneously either parallel to one another or with an inclination to one another at the same or different regions of the workpiece which is held in a holder capable of both rotating the workpiece and translating same.

Abstract: A subminiature circuit protector includes a substrate carrying a metal fuse element hermetically sealed in a glass sleeve cartridge. The fuse element may comprise a film deposited on the substrate, or, alternatively a metal strip or wire. Leads extend from opposing ends of the sleeve for connection in a circuit, and a gas is sealed in the sleeve to provide a suitable environment to improve operating lifetime and interrupting capability. A method for making a circuit protector includes placing a substrate carrying a fuse element in a glass sleeve and placing leads in contact with the fuse element. The assembly is heated in the presence of a gas below atmospheric pressure to a temperature sufficient to soften the glass. The pressure is then increased to cause the ends of the glass sleeve to form a hermetic seal about the leads.

Abstract: The method for manufacturing a sample tube for the use in a nuclear magnetic resonance apparatus comprising the steps of: inserting a core bar into a tubular body made of glass or quartz, the core bar having a stepped portion and a remaining portion, the portion of the core bar with the stepped portion corresponding to a sample receiving chamber being larger in diameter than the remaining portion; gradually inserting the tubular body into an electric furnace for heating while allowing suction from a vacuum pump to act on the interior of the tubular body, thereby the whole tubular body being intimately attached for shaping to and along an outer peripheral surface of the core bar; withdrawing the core bar outside from a lower end opening of the tubular body; sealing by heating the lower end opening of the tubular body to form a bottom of the tube; and grinding the peripheral surface so that the whole tubular body will be equal in outer diameter.

Abstract: An evacuated vial for collecting a fluid sample and a method for manufacturing the vial comprising a cylindrical glass tube, one end of the tube formed into a frangible tip, a glass bottom closing off the other end of the tube, and a depression formed in the bottom forming an internal breaking tip extending into said tube. The bottom of the tube is sealed in a manner permitting convenient puncture thereof to break the tip when a sample is to be delivered.

Abstract: Disclosed is a method of forming a glass tube doped with boron and fluorine. A B.sub.2 O.sub.3 -doped tubular porous preform is heated, and a fluorine-containing gas is flowed into its aperture. The temperature is sufficiently high to cause the fluorine-containing gas to decompose and form fluorine which dopes the preform. Also flowed into the aperture is a sufficient amount of BF.sub.3 to prevent fluorine from reacting with the B.sub.2 O.sub.3 in the porous preform and forming a B.sub.2 O.sub.3 -depleted region near the aperture surface. The particles are then fused to form a fluorine-containing dense glass tube.

Abstract: The invention relates to a method of making multi-ferrules. It provides a method of making multi-ferrules from a vitreous material, the multi-ferrules having a series of cylindrical channels with parallel axes.

Abstract: A miniaturized sensor element is prepared using a capillary having first and second ends with a channel therebetween. One of the ends is closed while the other is open. Near the closed end, the capillary material which softens when heated, is heated and gas is supplied to the open end. This expands a chamber near the closed end which can be shaped and sized by moving the point of heating and varying the gas supply into the channel. The initially closed end is then opened and the channel inverted. The initially open end is then closed and again the capillary is heated and gas is supplied to form and shape a second chamber in the channel. After this, the closed end of the channel is again opened and both now open ends are smoothed to complete the capillary for use as part of a miniaturized sensor element.