Method and apparatus for refining glass in a melting tank

Claim 1

A glass melting apparatus comprising: an elongated tank body for containing molten glass and having an inlet end for receiving glass forming material and an outlet end for glass leaving said tank body for use in a forming process, said tank body defining: a. a melting region adjacent said inlet end for melting the glass forming material, b. a refining region downstream of said melting region for refining the molten glass, c. a conditioning zone adjacent said outlet end for conditioning the refined glass, and d. an intermediate zone leading from said refining region to said conditioning zone; said intermediate zone and said conditioning zone being substantially narrow relative to said refining region; flow control means for physically slowing up the forward flow of the upper levels of glass out of said refining region and into said narrower intermediate and conditioning zones; said refining region and said intermediate zone being sufficiently deep for forward and return flow of molten glass to take place; said intermediate zone having a step at its downstream end adjacent said conditioning zone, and said conditioning zone having a raised base thereby providing a shallow conditioning channel along which molten glass may flow in the direction of said outlet with substantially no return flow.

Claim 18

A method of manufacturing glass comprising feeding glass forming material into one end of a glass melting tank, melting the material in a melting zone of the tank adjacent an inlet end of the tank, refining the molten material at a refining zone downstream of the melting zone, and conditioning the molten glass in a shallow conditioning zone adjacent an outlet end of the tank so that the molten glass leaves the tank ready for use in a forming process, said method further comprising passing the molten glass from an inlet end of a glass melting tank through a wide body portion including said refining zone and subsequently through a substantially narrower channel, including said shallow conditioning zone and a deeper intermediate zone leading from said refining zone to said conditioning zone, towards the outlet end, said refining zone and said intermediate zone being sufficiently deep for forward and return flow of molten glass to take place, enforcing temperature gradients within the melting, refining and intermediate zones and enforcing forward and return flows of molten glass in the melting. refining and intermediate zones, limiting the downstream position of the return flow at a step in the base of the narrow channel at the juncture of said intermediate and conditioning zones, and further physically slowing up the forward flow of the upper levels of molten glass into the intermediate zone by flow control means, whereby the glass enters the shallow conditioning zone at a temperature suitable for conditioning and flows in the direction of the outlet with substantially no return flow in the shallow conditioning zone.

Claim 19

A method of manufacturing glass comprising feeding glass forming material into one end of a glass melting tank, melting the material in a melting zone of the tank adjacent an inlet end of the tank, refining the molten material at a refining zone downstream of the melting zone, and conditioning the molten glass in a shallow conditioning zone adjacent an outlet end of the tank so that the molten glass leaves the tank ready for use in a forming process, said method further comprising passing the molten glass from an inlet end of a glass melting tank through a wide body portion including said refining zone and subsequently through a substantially narrower channel, including said shallow conditioning zone and a deeper intermediate zone leading from said refining zone to said conditioning zone, towards the outlet end, said refining zone and said intermediate zone being sufficiently deep for forward and return flow of molten glass to take place, enforcing temperature gradients within the melting, refining and intermediate zones and enforcing forward and return flows of molten glass in the melting. refining and intermediate zones, limiting the downstream position of the return flow at a step in the base of the narrow channel at the juncture of said intermediate and conditioning zones, and further physically slowing up the forward flow of the upper levels of molten glass into the intermediate zone by flow control means, whereby the glass enters the shallow conditioning zone at a temperature suitable for conditioning and flows in the direction of the outlet with substantially no return flow in the shallow conditioning zone.