Ppg Industries, Inc.

James L Oravitz, Jr

John R Dahlberg

William R Siskos

Thomas Patrick Kerr

Charles J Hyatt

Shaow B Lin

Peter P Harmon

Paul E Shaffer

Harold R Gorman

A vacuum insulating unit has a pair of glass sheets spaced from one another by a plurality of plastic supports. The supports have one end secured to one of the sheets and a low friction material on the other end. A flexible metal edge retainer is secured to sheets to provide a sealed compartment between the sheets. Air in the compartment is removed to put the compartment under negative pressure. A getter is provided in the compartment to adsorb any gas therein during sealing or using the unit. One of the sheets may have an environmental coating. Methods are disclosed for fabricating the unit and the supports.

Vacuum insulating unit

Damage free scores are initiated in a refractory piece by advancing a pattern of grit material on the surface of the refractory piece under a properly biased scoring wheel. The grit material is preferably harder than the surface of the refractory piece but not as hard as the scoring surface of the scoring wheel.

Method of imposing a damage free score in a refractory piece

A glass ribbon moves downstream under a pair of scoring wheels to score the bulb edges of the ribbon and thereafter past a cross scorer to laterally score the ribbon. As the ribbon moves further downstream the scores at the bulb edge move under (1) a plurality of hot airstreams which propagate the fissure depth of the score and (2) under a cold airstream to concentrate the stress field about the score line to prevent premature severing of the bulb edges due to mechanical vibrations generated during subsequent opening of the lateral score.

Method of and apparatus for preventing premature severing of scored

A cutting fluid is disclosed comprising one or more halogenated hydrocarbons dissolved in one or more paraffin, naphtha, or aromatic solvents. Use of the cutting fluid produces a glass edge with increased edge strength compared with a cut edge produced by dry scoring. The cutting fluid is completely evaporative, leaving no residue, thus eliminating the need for washing. Further, use of the cutting fluid extends the useful life of the cutting tool. Blends are formulated to meet specific evaporation rates required by variations in wareroom equipment and practices.

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Cheswick, PA, United States of America

James L Oravitz, Jr