Inventors:
Eugene W. Starr - Allison Park PA
Assignee:
PPG Industries, Inc. - Pittsburgh PA
International Classification:
C03B 2302
Abstract:
Apparatus for thermally treating glass sheets comprising a combustion chamber, a kiln and a hot gas delivery system for delivering a mixture comprising combustion products into the kiln in such a manner as to avoid deviations from a substantially uniform temperature pattern across the kiln suitable for sag bending and annealing glass sheets.
The delivery system comprises a delivery pipe, means for dividing said mixture into two approximately equal flows of said mixture for supplying said flows through a pair of branch pipes, then through the length of a pair of manifolds, each comprising an open ended inner pipe, and a concentric apertured outer pipe. The outer pipes have upwardly directed nozzles of substantially equal cross-section located at approximately uniformly spaced intervals along their length. The mixture flows into the kiln upwardly from said nozzles at a substantially uniform temperature along the length of the outer pipes and blends with the kiln atmosphere to provide a more uniform temperature pattern than is obtained from prior art kiln temperature control systems.