US 3,976,460 AGranted

Method and apparatus for introducing a protective atmosphere into a glass forming chamber

AssigneePPG Industries, Inc.

InventorsJohn W. Kompare, John C. Potts, James L. Simpson

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Abstract

The glass forming chamber in which glass is formed into a continuous sheet by floating it on the surface of molten metal is provided with a series of heat exchangers in an enclosed shell above the chamber and protective atmosphere gases are passed through these heat exchangers to preheat the atmosphere gases which are then directed through conduits into headers and distribution manifolds located within the headspace of the operating portion of the chamber in the vicinity of the glass being formed. The chamber is provided with conventional electrical heating elements connected to bus bars located within the shell containing the heat exchangers, and the heat exchangers are located close to the bus bars to extract heat from them during operation and thereby prolong their useful lives.

Claims23

Dependent claims

In the method of making flat glass wherein molten glass is delivered onto the surface of a pool of molten metal in an enclosed chamber that includes a ceiling separating the chamber into two enclosed spaces, a headspace below the ceiling and a service space above the ceiling, and is advanced as a layer along the surface of the pool of molten metal while being cooled and formed into a dimensionally stable, continuous sheet of glass which is withdrawn from the pool of molten metal and from the enclosed chamber and wherein a protective atmosphere gas is introduced into the chamber in the headspace extending over the advancing glass and the pool of molten metal and wherein heat is supplied in said headspace from heaters while the service space above them inherently receives heat, the improvement comprising

directing a portion of the introduced protective gas through a heat exchanger located inside the service space of the chamber and closely spaced in effective heat exchange relation to a first portion of the service space of the chamber which is substantially hotter than a second portion of the service space of the chamber and then
distributing a substantial amount of the introduced protective gas that has been directed through the heat exchanger in the first portion of the service space of the chamber into the headspace of the chamber at a location beneath the second portion of the service space of the chamber whereby a hotter portion of the service space is cooled while heat removed therefrom is directed into a location of the headspace of the chamber beneath a colder portion of the service space.

In an apparatus for making flat glass comprising an enclosed chamber having an outer casing, a liner within the bottom portion of the casing containing a pool of molten metal, a ceiling disposed within the chamber and separating it into two spaces, a headspace beneath the ceiling and above the pool of molten metal and a service space above the ceiling and inside the outer casing, wherein heaters are mounted within the headspace of the chamber in spaced facing relation to the pool of molten metal, which heaters are connected to power connectors mounted within the service space of the chamber, the improvement comprising

a plurality of heat exchangers, each having an inlet and an outlet, positioned within the service space of the chamber,
an inlet conduit for supplying a protective gas to the chamber connected to the inlet of each heat exchanger,
an outlet conduit for carrying the protective gas from a heat exchanger to the headspace of the chamber connected to the outlet of each heat exchanger,
at least one gas distribution means for distributing the protective gas into the headspace of the chamber connected to each outlet conduit and mounted inside the headspace of the chamber.

1 more element

Dependencies are inferred from the claim text.