Methods and apparatuses for producing laminated glass sheets

• US 9,458,044 B2
• Filed: 07/13/2012
• Issued: 10/04/2016
• Est. Priority Date: 07/13/2012
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Lereboullet, Jean-Pierre Henri Ren, Bisson, Antoine Gaston Denis, Fournel, Olivier, Fredholm, Allan Mark, Joubaud, Laurent, Tellier, Xavier
• Primary Examiner(s): Halpern, Mark
• Application Number:
  US14/413,625
• Publication Number:
  US 20150191387A1
• Time in Patent Office: 1,544 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C03B 17/02 Forming molten glass coated with coloured layers; Forming molten glass of different compositions or layers; Forming molten glass comprising reinforcements or inserts
• CPC Class Codes: C03B 18/02 Forming sheets
• CPC Class Codes: C03B 18/06 using mechanical means, e.g. restrictor bars, edge rollers
• CPC Class Codes: C03B 18/12 Making multilayer, coloured or armoured glass chemical aspects C03C
• CPC Class Codes: C03B 5/267 specially adapted for supplying the float tank
• CPC Class Codes: C03B 7/08 Feeder spouts, e.g. gob feeders
• CPC Class Codes: Y02P 40/57 Improving the yield, e-g- reduction of reject rates

Abstract

According to one embodiment, a method for forming a laminated glass sheet includes forming a multi-layer glass melt (300) from a molten core glass (106) and at least one molten cladding glass (126). The multi-layer glass melt (300) has a width W_m, a melt thickness T_m and a core to cladding thickness ratio T_C:T_Cl. The multi-layer glass melt (300) is directed onto the surface of a molten metal bath (162) contained in a float tank (160). The width W_m of the multi-layer glass melt (300) is less than the width W_f of the float tank (160) prior to the multi-layer glass melt (300) entering the float tank (160). The multilayer glass melt (300) flows over the surface of the molten metal bath (162) such that the width W_m of the multi-layer glass melt (300) increases, the melt thickness T_m decreases, and the core to cladding thickness ratio T_C:T_Cl remains constant as the multi-layer glass melt (300) solidifies into a laminated glass sheet. The invention also relates to the associated apparatus.

Claims

1. A method for forming a laminated glass sheet, the method comprising:

forming a multi-layer glass melt from a molten core glass and at least one molten cladding glass, wherein the multilayer glass melt has a width W_m, a melt thickness T_m and a core to cladding thickness ratio T_c;

T_cl;

directing the multi-layer glass melt onto the surface of a molten metal bath contained in a float tank having a width W_f, wherein the width W_m of the multi-layer glass melt is less than the width W_f of the float tank prior to entering the float tank; and

flowing the multi-layer glass melt over the surface of the molten metal bath such that the width W_m increases, the melt thickness T_m decreases, and the core to cladding thickness ratio T_c;

T_cl remains constant as the multi-layer glass melt solidifies into the laminated glass sheet.

2. The method of claim 1, further comprising drawing the multi-layer glass melt in a direction of the width W_f of the float tank as the multi-layer glass melt flows over the surface of the molten metal bath.

3. The method of claim 1, further comprising drawing the multi-layer glass melt in a direction of the width W_f of the float tank and a length L_f of the float tank as the multi-layer glass melt flows over the surface of the molten metal bath.

4. The method of claim 1, further comprising directing the multi-layer glass melt onto a receiving surface of a receiving plane prior to directing the multi-layer glass melt onto the surface of the molten metal bath.

5. The method of claim 4, wherein the receiving surface of the receiving plane is oriented at a receiving plane angle greater than or equal to 0°

and less than 90°

with respect to a surface of the molten metal bath.

6. The method of claim 1, wherein the multi-layer glass melt is formed by:

melting a core glass composition into the molten core glass;

melting a cladding glass composition into the at least one molten cladding glass; and

delivering the molten core glass and the at least one molten cladding glass to a slot draw apparatus comprising a core glass slot and at least one cladding glass slot such that the molten core glass passes through the core glass slot and the at least one molten cladding glass passes through the at least one cladding glass slot, wherein the slot draw apparatus layers the at least one molten cladding glass and the molten core glass as the molten core glass and the at least one molten cladding glass exit the slot draw apparatus thereby forming the multi-layer glass melt.

7. The method of claim 6, wherein the core glass slot and the at least one cladding glass slot are oriented in parallel with one another.

8. The method of claim 6, wherein the slot draw apparatus is positioned over the float tank containing the molten metal bath and oriented at a slot angle greater than or equal to 0°

and less than 90°

with respect to a surface of the molten metal bath.

9. The method of claim 6, wherein a width W_s of the slot draw apparatus is less than the width W_f of the float tank.

10. The method of claim 6, wherein the at least one cladding slot of the slot draw apparatus comprises a first cladding slot and a second cladding slot and the core slot is positioned between the first cladding slot and the second cladding slot.

11. The method of claim 10, wherein the first cladding slot has a first height H_cla and the second cladding slot has a second height H_clb and the first height H_cla is not equal to the second height H_clb.

12. The method of claim 10, wherein the core slot has a core height H_c, the first cladding slot has a first height H_cla and the second cladding slot has a second height H_clb, wherein the core height H_c is greater than the first height H_cla and the second height H_clb.

13. The method of claim 6, wherein each of the core slot and the at least one cladding slot comprises a plurality of reinforcing webs.

14. The method of claim 13, wherein the reinforcing webs are recessed from an outlet of the slot draw apparatus.

15. The method of claim 1 wherein the laminated glass sheet has a width greater than 4 meters.

16. The method of claim 1, further comprising:

contacting an upper surface of the multi-layer glass melt with a plurality of top rollers when the multi-layer glass melt is on the surface of the molten metal bath; and

drawing the multi-layer glass melt in a direction of the width W_f of the float tank with the plurality of top rollers.

17. The method of claim 1, further comprising:

contacting an upper surface of the multi-layer glass melt with a plurality of top rollers when the multi-layer glass melt is on the surface of the molten metal bath; and

drawing the multi-layer glass melt in a direction of the width W_f and a length L_f of the float tank with the plurality of top rollers.

18. The method of claim 1, wherein an average core coefficient of thermal expansion CTE_core of the molten core glass is greater than an average cladding coefficient of thermal expansion CTE_clad of the at least one molten cladding glass.

19. The method of claim 1, wherein the molten core glass has a liquidus viscosity less than 100 kpoise.

20. The method of claim 1, wherein the at least one molten cladding glass has a liquidus viscosity less than 100 kpoise.