Selective chemical fining of small bubbles in glass
A method of fining glass is disclosed that includes flowing a molten glass bath through a fining chamber. The molten glass bath has an undercurrent that flows beneath a skimmer that is partially submerged in the molten glass bath. One or more fining agents are introduced into the undercurrent of the molten glass bath directly beneath the skimmer from a carrier gas. In this way, the fining agent(s) may selectively target the gas bubbles drawn under the skimmer within the undercurrent of the molten glass bath for removal. The method may be employed to fine molten glass produced in a submerged combustion melter. A fining vessel for fining molten glass is also disclosed.
1 . A method of fining glass, the method comprising:
supplying input molten glass into a fining chamber of a fining vessel, the input molten glass combining with a molten glass bath contained within the fining chamber and introducing entrained gas bubbles into the molten glass bath, the input molten glass having a density and a concentration of gas bubbles;
flowing the molten glass bath through the fining chamber in a flow direction, the molten glass bath having an undercurrent that flows beneath a skimmer, which is partially submerged in the molten glass bath, and through a submerged passageway defined in part by the skimmer; and
introducing a carrier gas into the undercurrent of the molten glass bath directly beneath the skimmer, the carrier gas comprising suspended particles of one or more fining agents.
2 . The method set forth in claim 1 , wherein the carrier gas includes a main gas that supports the suspended particles of the one or more fining agents.
3 . The method set forth in claim 2 , wherein the main gas is air or nitrogen.
4 . The method set forth in claim 1 , wherein the one or more fining agents includes a sulfate that decomposes to release O 2 and SO 2 fining gases.
5 . The method set forth in claim 1 , wherein the one or more fining agents includes sodium sulfate, Cr 2 O 3 , WO 3 , carbon, aluminum, a carbonate, silicon carbide, oxidized metal powder, or combinations thereof.
6 . The method set forth in claim 1 , wherein the fining vessel includes a housing that defines the fining chamber, and wherein the carrier gas is introduced into the molten glass bath from a plurality of nozzles that are supported within a floor of the housing.
7 . The method set forth in claim 6 , wherein the plurality of nozzles are spaced apart along a width of the fining chamber beneath the skimmer to provide a row of carrier gas effervescence that extends transverse to the flow direction of the molten glass bath and rises upwards from the floor of the housing.
8 . The method set forth in claim 1 , wherein the input molten glass has a soda-lime-silica glass chemical composition.
9 . The method set forth in claim 1 , further comprising:
discharging output molten glass from the fining vessel, the output molten glass having a density that is greater than the density of the input molten glass and further having a concentration of gas bubbles that is less than the concentration of gas bubbles of the input molten glass.
10 . A method of producing and fining glass, the method comprising:
discharging combustion products from one or more submerged burners directly into a glass melt contained within an interior reaction chamber of a submerged combustion melter, the combustion products discharged from the one or more submerged burners agitating the glass melt;
discharging foamy molten glass obtained from the glass melt out of the submerged combustion melter;
supplying the foamy molten glass into a fining chamber of a fining vessel as input molten glass, the input molten glass combining with a molten glass bath contained within the fining chamber and introducing entrained gas bubbles into the molten glass bath, the input molten glass having a density and comprising up to 60 vol % bubbles;
flowing the molten glass bath through the fining chamber in a flow direction, the molten glass bath having an undercurrent that flows beneath a skimmer, which is partially submerged in the molten glass bath, and through a submerged passageway defined in part by the skimmer;
introducing a carrier gas into the undercurrent of the molten glass bath directly beneath the skimmer, the carrier gas comprising suspended particles of one or more fining agents; and
discharging output molten glass from the fining vessel, the output molten glass having a density that is greater than the density of the input molten glass.
11 . The method set forth in claim 10 , wherein the carrier gas includes a main gas that supports the suspended particles of the one or more fining agents.
12 . The method set forth in claim 11 , wherein the main gas is air or nitrogen, and the one or more fining agents includes sulfate particles suspended in the main gas.
13 . The method set forth in claim 10 , wherein the one or more fining agents includes sodium sulfate, Cr 2 O 3 , WO 3 , carbon, aluminum, a carbonate, silicon carbide, oxidized metal powder, or combinations thereof.
14 . The method set forth in claim 10 , wherein the glass melt in the submerged combustion melter and the molten glass bath in the fining vessel have a soda-lime-silica glass chemical composition.
15 . The method set forth in claim 14 , further comprising:
forming the output molten glass discharged from the fining vessel into at least one glass container having an axially closed base and a circumferential wall, the circumferential wall extending from the axially closed base to a mouth that defines an opening to a containment space defined by the axially closed base and the circumferential wall.
16 . A fining vessel for fining glass, the fining vessel comprising:
a housing that defines a fining chamber, the housing having a roof, a floor, and an upstanding wall that connects the roof and the floor, the housing further defining an inlet to the fining chamber and an outlet from the fining chamber;
a skimmer extending downwards from the roof of the housing towards the floor of the housing and further extending across the fining chamber between opposed lateral sidewalls of the upstanding wall, the skimmer having a distal free end that together with corresponding portions of the floor and upstanding wall defines a submerged passageway; and
a plurality of nozzles supported in the floor of the housing directly beneath the skimmer, each of the nozzles being configured to dispense a carrier gas into the fining chamber directly beneath the skimmer, the carrier gas including a main gas that contains suspended particles of one or more fining agents.
17 . The fining vessel set forth in claim 16 , wherein the plurality of nozzles are spaced apart along a width of the fining chamber beneath the skimmer.
18 . The fining vessel set forth in claim 17 , wherein the plurality of nozzles are contained within a refractory support block that is received in a channel defined in the floor of the housing, wherein the channel extends across the width of the fining chamber.
19 . The fining vessel set forth in claim 18 , wherein the refractory support block is slidably received within the channel.
20 . The fining vessel set forth in claim 18 , wherein each of the plurality of nozzles further includes a feeder line, and wherein the refractory support block also contains a carrier gas supply conduit that fluidly communicates with the feeder line of each of the plurality of nozzles such that the carrier gas is supplied to the plurality of nozzles from the carrier gas supply conduit.