Abstract: The present invention discloses improved apparatuses for forming sheet glass. In one embodiment, the invention introduces a structural web that supports the forming structure in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming structure.

Abstract: The present invention discloses improved methods and apparatus for forming sheet glass. In one embodiment, the invention introduces a counteracting force to the stresses on the forming structure in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming structure.

Abstract: A method keeps the width of the manufactured sheet substantially the same by attaching edge directors for the formed sheet to the manufacturing apparatus structure instead of to the forming block. Thus, sheet glass may be manufactured to specification for a longer time with the same forming block. An additional method adjusts the width of the manufactured sheet by changing the distance between the edge directors. Thus sheet glass may be manufactured to different width specifications with the same forming block.

Abstract: The present invention discloses improved methods and apparatus for forming sheet glass. In one embodiment, the invention introduces a counteracting force to the stresses on the forming structure in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming structure.

Abstract: A molten glass delivery system is modified to match it with the overflow downdraw process. A substantial number of defects not removed by the finer are diverted to the unusable inlet and distal edges of the sheet. In one embodiment, the stirring device is relocated from the outlet to the inlet of the finer. In another embodiment, the basic shape of the finer is preferably changed from a cylindrical shape to a Double Apex (or Gull Wing) shaped cross-section, whereby the apexes of the finer contain the glass that will form the unusable inlet end of the glass sheet. The finer vent or vents are preferably located at these apexes such that any homogeneity defects caused by the vents are diverted to the unusable inlet end of the glass sheet. The finer cross-section has a high aspect ratio for increased fining efficiency as compared to a cylindrical finer.

Abstract: A bone screw deforms on the same order as the bone, thus providing substantially uniform loading along an entire length of the thread of the bone screw. The bone screw of the present invention evenly distributes stress by matching the effective cross-sectional area of the bone screw times its modulus of elasticity with the effective cross-sectional area of the parent material (i.e. bone) times its modulus of elasticity so that they are preferably substantially equal to each other.

Abstract: The forming apparatus of the present invention preferably includes an orifice on top of the trough. The uniquely shaped orifice substitutes for the weirs as the controlling entity for glass thickness. The orifice is designed such that as it deforms, it maintains a linear flow characteristic with respect to its length. As the orifice is made larger by the applied stress, the percentage width increase is the same over its length and consequently the percentage flow increase is the same over the length of the orifice. In another embodiment, the present invention provides an adjustment to change the flow characteristics of the trough to compensate for the degradation of the forming trough during an extended production run. A flow control plug can be inserted into the trough, such that flow dynamics can be altered during hot operation by insertion, removal or position adjustment of the flow control plug.

Abstract: The present invention alters the flow path at the inlet of the sheet glass forming apparatus to improve quality. The bottom of the downcomer pipe is preferably shaped to alter the character of the vortex flow in the quiescent flow zone between the pipes. In another embodiment, a bead guide provides hydraulic stresses that are in opposition to the surface tension stress and thus reduces the influence of surface tension on the formation of thick beads on the edges of the sheet. The present invention also measures the temperature of the glass by immersing thermocouples in the glass, at locations where any defects caused by the immersion are in the glass that forms the unusable edges of the sheet. In another embodiment, the support structure for the trough is altered to substantially reduce the aging of the trough due to thermal creep.

Abstract: The present invention alters the flow path at the inlet of the sheet glass forming apparatus to improve quality. The bottom of the downcomer pipe is preferably shaped to alter the character of the vortex flow in the quiescent flow zone between the pipes. In another embodiment, a bead guide provides hydraulic stresses that are in opposition to the surface tension stress and thus reduces the influence of surface tension on the formation of thick beads on the edges of the sheet. The present invention also measures the temperature of the glass by immersing thermocouples in the glass, at locations where any defects caused by the immersion are in the glass that forms the unusable edges of the sheet. In another embodiment, the support structure for the trough is altered to substantially reduce the aging of the trough due to thermal creep.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces. In an alternative embodiment, the glass is preferentially cooled across its width to create forming stresses during solidification, which ensures that the glass sheet drawn is inherently flat.

Abstract: The present invention alters the flow path at the inlet of the sheet glass forming apparatus to improve quality. The bottom of the downcomer pipe is preferably shaped to alter the character of the vortex flow in the quiescent flow zone between the pipes. In another embodiment, a bead guide provides hydraulic stresses that are in opposition to the surface tension stress and thus reduces the influence of surface tension on the formation of thick beads on the edges of the sheet. The present invention also measures the temperature of the glass by immersing thermocouples in the glass, at locations where any defects caused by the immersion are in the glass that forms the unusable edges of the sheet. In another embodiment, the support structure for the trough is altered to substantially reduce the aging of the trough due to thermal creep.

Abstract: A molten glass pump preferably includes one or more pumps which form either a single-stage apparatus or are combined in series to form a multi-stage apparatus. The exact configuration depends on the required process pressure and the required degree of glass homogenization. Examples of the invention include an auger pump and a mixing auger pump which have varying degrees of mixing action, as well as a homogenizing pump which provides some pumping action but is primarily a homogenizer. All three pumps preferably include a centerline flow recirculation feature which remixes inhomogeneous glass into the incoming glass stream. A counter-rotating sleeve, which straightens the glass flow exiting the apparatus and provides an additional flow recirculation path, is also preferably included.

Abstract: The basic shape of the molten glass fining apparatus of the present invention is preferably either an elliptical or a somewhat rectangular shape such that the flow is more uniform and the bubbles have less distance to rise to the surface. A novel baffle design is also shown. The present invention improves the fining capability of the apparatus without increasing the cost of construction materials. In fact, the cost may be reduced.

Abstract: The disclosure teaches design features that can be used alone or in combination to facilitate faster, more uniform flow of glass through the apparatus and allows the thickness of the sheet to be adjusted. An overflow device is provided at the far end of the trough and is used in conjunction with tilting of the apparatus to expand the range of glass flow rate and glass viscosity for which this invention will produce satisfactory product. The forming apparatus can be made with non-linear weirs and the trough bottom to provide a greater range of flow rates. The glass flow in the inflow pipe can modulated or a contoured trough cross-section used to provide more uniform time dependent flow for forming the sheet. The forming apparatus can include an orifice on top of the trough and glass can be moved through the apparatus using pressure. Additional orifices can be provided on the bottom or sides to allow greater variability in sheet thickness.

Abstract: One embodiment of the present invention is an improved sheet glass forming apparatus. In another embodiment, a precise thermal control system redistributes the flow of molten glass at the weirs to counteract the degradation of the sheet forming apparatus which inevitably occurs during manufacturing. In yet another embodiment, the invention introduces a counteracting force to the stresses on the trough in a manner such that the thermal creep which inevitably occurs has a minimum impact on the glass flow characteristics of the forming trough. Another embodiment creates a variable external cross-section which provides hydraulic stresses that are in opposition to the surface tension and body force stresses and thus, reduces the influence of surface tension and body forces. In an alternative embodiment, the glass is preferentially cooled across its width to create forming stresses during solidification, which ensures that the glass sheet drawn is inherently flat.

Abstract: A molten glass pump preferably includes one or more pumps which form either a single-stage apparatus or are combined in series to form a multi-stage apparatus. The exact configuration depends on the required process pressure and the required degree of glass homogenization. Examples of the invention include an auger pump and a mixing auger pump which have varying degrees of mixing action, as well as a homogenizing pump which provides some pumping action but is primarily a homogenizer. All three pumps preferably include a centerline flow recirculation feature which remixes inhomogeneous glass into the incoming glass stream. A counter-rotating sleeve, which straightens the glass flow exiting the apparatus and provides an additional flow recirculation path, is also preferably included.

Abstract: The disclosure teaches design features that can be used alone or in combination to facilitate faster, more uniform flow of glass through the apparatus and allows the thickness of the sheet to be adjusted. An overflow device is provided at the far end of the trough and is used in conjunction with tilting of the apparatus to expand the range of glass flow rate and glass viscosity for which this invention will produce satisfactory product. The forming apparatus can be made with non-linear weirs and the trough bottom to provide a greater range of flow rates. The glass flow in the inflow pipe can modulated or a contoured trough cross-section used to provide more uniform time dependent flow for forming the sheet. The forming apparatus can include an orifice on top of the trough and glass can be moved through the apparatus using pressure. Additional orifices can be provided on the bottom or sides to allow greater variability in sheet thickness.

Abstract: This invention contemplates a near net-shape method of making thin glass-ceramic articles possessing substantially uniform thickness and parallel opposing surfaces comprising the steps of: (a) heating the receiving and opposing molding surfaces of a mold to predetermined different temperatures; (b) bringing the receiving and opposing molding surfaces of the mold into close proximity to each other to press a delivered charge of molten glass to fill said mold, while thermally providing and maintaining a substantially parallel fit between the receiving and opposing surfaces of the mold, to achieve substantially uniform thickness in the pressed charge, (c) pressing the glass charge for a time sufficient to remove enough heat from the glass charge that the temperatures of the molding surfaces and the glass article surfaces are all nearly at equilibrium, wherein the press time and mold temperature differential combine to result in symmetric heat removal thereby causing all the aforementioned temperatures to reach e

Abstract: In a mold apparatus, the receiving molding surface and the opposing molding surface are each mounted coaxially and in sliding fashion within an alignment means. Both of these alignment means have an equal number of spaced apart alignment pads which are positioned such that opposing pads will be in cooperable engagement with each other during pressing.Utilizing the disclosed apparatus, a method for molding precisely shaped articles, such as magnetic memory disc substrates which require precisely parallel, opposite molded surfaces, is described. Simply stated, the method utilizes the alignment pads' thermal expansion characteristics to induce a controlled level of thermal distortion to obtain pad lengths which result in parallel opposing molding surfaces.