Glass sheet annealing lehr having gas support conveyor

A glass sheet strip annealing lehr comprising:

• a housing defining a heated chamber and having an entry end for receiving a heated continuous glass sheet strip having lower and upper surfaces just after forming of the strip, said housing having an exit end from which the strip exits the heated chamber, and the heated chamber having a decreasing temperature from the entry end of the housing toward the exit end thereof to provide cooling that anneals the strip;
• and
• a conveyor including a gas support means including lower and upper manifolds having elongated supply and exhaust openings that extend transversely to the glass sheet strip in a parallel and alternating relationship to each other and respectively deliver upwardly and downwardly directed pressurized gas, the upwardly delivered pressurized gas providing the sole support of the glass sheet strip within the housing until the surfaces of the strip are cooled below the strain point, the elongated exhaust openings that extend parallel to the elongated supply openings in a parallel and alternating relationship thereto receiving gas from the supply openings after impingement with the glass sheet strip, each manifold including at least one mixing plenum and a gas burner, each manifold including a pair of gas jet pumps for receiving the heated products of combustion from the gas burner thereof for mixing with gas returned from the elongated exhaust openings to provide gas flows to the mixing plenum which feeds the elongated supply openings, the pair of gas jet pumps being mounted at different elevations and arranged to provide the gas flows therefrom in opposite directions with respect to each other to enhance gas mixing of the gas flows from the pair of jet pumps within the mixing plenum, and the conveyor including a drive for engaging the strip after the surfaces thereof are cooled below the strain point to pull the strip from the entry end of the housing toward the exit end thereof over the gas support means.

A glass sheet strip annealing lehr comprising:

• a housing defining a heated chamber and having an entry end for receiving a heated continuous glass sheet strip having lower and upper surfaces just after forming of the strip, said housing having an exit end from which the strip exits the heated chamber, and the heated chamber having a decreasing temperature from the entry end of the housing toward the exit end thereof to provide cooling that anneals the strip;
• and
• a conveyor including a gas support means including lower and upper manifolds each of which includes a platen cast from refractory material to define elongated supply openings that extend transversely to the glass sheet strip in a parallel relationship to each other and deliver upwardly and downwardly directed pressurized gas to provide the sole support of the glass sheet strip within the housing until the surfaces of the strip are cooled below the strain point, the platen of each manifold also having elongated exhaust openings that extend parallel to the elongated supply openings in a parallel relationship thereto and receive gas from the supply openings after impingement with the glass sheet strip, each manifold also including a manifold member cast from a refractory material and having a mixing plenum from which pressurized gas is fed to the supply openings of the platen, each manifold member also having at least one return passage that receives the gas from the supply openings after impingement with the glass sheet strip, a pair of gas jet pumps mounted by the manifold member of each manifold to receive gas returned from the exhaust openings, each manifold also including a gas burner that feeds heated products of combustion to the gas jet pumps thereof to provide a primary gas flow that induces a secondary gas flow of gas returned from the exhaust openings to provide gas flows to the mixing plenum from which the gas is delivered to the supply openings, the pair of gas jet pumps being mounted at different elevations and arranged to provide the gas flows therefrom in opposite directions with respect to each other to enhance gas mixing of the gas flows from the pair of jet pumps within the mixing plenum prior to delivery to the supply openings, and the conveyor including a drive for engaging the strip after the surfaces thereof are cooled below the strain point to pull the strip from the entry end of the housing toward the exit end thereof over the gas support means.