Float bath exit seal

Patent metadata

Field	Value
Publication number	US-11339078-B2
Application number	US-201716329843-A
Country	US
Kind code	B2
Filing date	Sep 1, 2017
Priority date	Sep 2, 2016
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

A method of reducing the volume of float bath atmosphere lost from an opening in the exit end of the float bath is described. The method comprises directing a first jet of fluid having a first jet velocity followed by a second jet velocity towards a plane a conveyance for a float glass ribbon. An obstruction in the path of the first jet of fluid causes the jet to change from the second to a third jet velocity. The obstruction may be a portion of a roller positioned outside the opening or a float glass ribbon that has been formed on a surface of molten metal contained in the float bath that has subsequently been transferred through the opening. A float bath having sealing means to reduce atmosphere loss from an exit of the float bath is also described, as is an assembly useful in carrying out the aforementioned methods.

First claim

The invention claimed is:

1. A method of reducing the volume of float bath atmosphere lost from an exit end of a float bath, the float bath comprising an enclosure for containing the bath atmosphere, the exit end comprising a first opening through which a ribbon of glass supported on a pool of molten metal contained in the enclosure can pass from inside the enclosure to a conveying means positioned outside the enclosure, the conveying means configured to convey the ribbon of glass in a first direction of conveyance away from the enclosure along a conveyance plane towards a second opening, the method comprising the step of (i) directing at least one (a first) jet of fluid towards the conveyance plane, the first jet of fluid having a first jet velocity and a subsequent second jet velocity, the first jet velocity of the first jet of fluid having a first jet speed and a first jet direction and the second jet velocity of the first jet of fluid having a second jet speed and a second jet direction; wherein the first jet of fluid is caused to change direction such that the second jet direction of the first jet of fluid is different to the first jet direction of the first jet of fluid; and further wherein the first jet of fluid having the second jet velocity is directed towards the conveyance plane downstream of the second opening and the first jet of fluid having the second jet velocity changes from the second jet velocity to a third jet velocity due to the presence of an obstruction in the path of the first jet of fluid having the second velocity to reduce the volume of bath atmosphere lost from the float bath via the second opening.

2. The method according to claim 1 , wherein the obstruction is positioned outside of the second opening.

3. The method according to claim 1 , wherein the obstruction comprises at least a portion of a roller.

4. The method according to claim 1 , wherein the first jet direction of the first jet of fluid and/or the second jet direction of the first jet of fluid is at an angle of 65° or less to the vertical.

5. The method according to claim 1 , wherein the third jet velocity of the first jet of fluid is zero or wherein the third jet direction of the first jet of fluid is in the direction of conveyance and/or wherein the first jet direction of the first jet of fluid or the second jet direction of the first jet of fluid is parallel to the vertical.

6. The method according to claim 1 , wherein the fluid is an inert fluid or a reducing fluid.

7. The method according to claim 1 , wherein the fluid is a gas.

8. The method according to claim 7 , wherein the gas comprises less than 1% by volume oxygen.

9. The method according to claim 1 , wherein the flow of fluid to the at least one jet is between F min and F max , with F min <F max and F min being between 5 Nm 3 /h and 80 Nm 3 /h and F max being between 90 Nm 3 /h and 500 Nm 3 /h.

10. The method according to claim 1 , wherein the first jet speed of the first jet of fluid and/or the second jet speed of the first jet of fluid is less than the speed of sound in dry air at 20° C.

11. The method according to claim 1 , wherein the obstruction is a float glass ribbon that has been formed on a surface of the pool of molten metal contained in the enclosure that has subsequently been transferred though the first opening or wherein the obstruction is an upper surface of a ribbon of glass.

12. The method according to claim 1 , wherein the obstruction comprises a deflecting element extending away from the second opening.

13. The method according to claim 1 , wherein the first jet of fluid is heated before and/or after moving in the first jet direction and/or the second jet direction.

14. The method according to claim 1 , wherein the first jet of fluid is caused to change direction from the first jet direction to the second jet direction by impacting on a deflecting surface.

15. The method according to claim 14 , wherein the deflecting surface is a barrier configured to reduce the volume of bath atmosphere lost from the second opening in the exit end of the float bath.

16. The method according to claim 14 , wherein the deflecting surface is at a temperature greater than 400° C.

17. A float bath comprising an enclosure for containing a reducing atmosphere and a hood section comprising a number of barriers extending between walls of the hood section, the enclosure having inlet means for introducing molten glass into the enclosure, and outlet means for allowing formed glass to exit the enclosure to a conveying means outside the enclosure, the conveying means having a conveyance plane, the outlet means comprising an exit barrier configured such that the formed glass exits the hood section through an opening defined by at least a portion of the exit barrier, wherein downstream of the exit barrier is located sealing means comprising an array or one or more nozzles configured to direct one or more jets of fluid, preferably gas, in a first jet direction followed by a second jet direction towards the conveyance plane, wherein the float bath further comprises means for deflecting the one or more jets of fluid towards the opening such that the first jet direction is different to the second jet direction of a respective jet of fluid.

18. The float bath according to claim 17 , further comprising at least one obstruction downstream of the outlet means, the at least one obstruction being configured to change the direction of the first jet of fluid from the second direction to a third direction.

19. The float bath according to claim 17 , wherein at least one nozzle of the array of one of more nozzles has a slit orifice.

20. The float bath according to claim 17 , wherein the obstruction is (i) a float glass ribbon; or (ii) at least a portion of a roller; or (iii) a deflecting element extending away from the opening.

Assignees

• Pilkington Group Ltd

Inventors

• Olverson Karl
• Parry Gavin
• Lynam Mark David
• Williams Ian Ross
• Lawrenson David

Classifications

• C03B18/20

  Composition of the atmosphere above the float bath; Treating or purifying the atmosphere above the float bath · CPC title

• C03B18/16 Primary

  Construction of the float tank; Use of material for the float tank; Coating or protection of the tank wall · CPC title