US3488177A - Device for trapping floating matter which floats atop a float glass molten metal bath - Google Patents

Description

3 Sheets-Sheet 1 INVENTORJ BYLU aQd-Q 1970 KIYOSHI ITAKURA E AL DEVICE FOR TRAPPING FLOATING MATTER WHICH FLUATS P A FLOAT GLASS MOLTEN METAL BATH Filed Dec. 27, 1966 IM ATTORNEY;

Jan. 6, 1970 KIYOSHI ITAKURA ET AL 3,488,177

DEVICE FOR TRAPPING FLOATING MATTER WHICH FLJUATS ATOP A FLOAT GLASS MOLTEN METAL BATH Filed Dec. 27, 1966 3 Sheets-Sheet 2 INVENTORS BY M ATTORNEYS United States Patent 3,488,177 DEVICE FOR TRAPPING FLOATING MATTER WHICH FLOATS ATOP A FLOAT GLASS MOLTEN METAL BATH Kiyoshi Itakura, Kobe, and Mamoru Hoshino, Nishinomiya-shi, Japan, assignors to Nippon Sheet Glass Co., Ltd., Osaka, Japan Filed Dec. 27, 1966, Ser. No. 604,803 Claims priority, application Japan, Jan. 17, 1966, 41/ 2,250 Int. Cl. C03b 18/00 US. Cl. 65168 Claims ABSTRACT OF THE DISCLOSURE Device for trapping floating matter undesirably formed atop a molten metal bath in a glass ribbon making apparatus includes at least one pocket provided in the neighborhood of the exit of the bath. A partition having an uneven upper edge separates the main bath from each pocket. A first part of the upper edge of the partition is above while a second part is below the level of the molten metal so that the floating matter may flow over said second part into the pocket. The partition is provided with an opening below the first part, wherethrough excess molten metal may pass back to the main bath while said floating matter is trapped in said pocket.

This invention relates to a device for trapping floating matter in an apparatus for manufacturing a glass ribbon, an apparatus wherein the glass is advanced over a bath of molten metal, and particularly to a device for trapping floating matter which floats atop the molten metal bath.

For protecting the molten metal in the manufacture of sheet glass using a molten metal bath, it is the practice to cover the bath with either a reducing or a neutral atmosphere. As a matter-of-fact it is however very difficult to eliminate completely the oxidizing and sulfurizing components in the atmosphere, and frequently oxides and sulfides of the molten metal are formed to appear on the surface of the molten metal bath as floating matter. Aside from this, broken pieces of glass and refractory material are also present at times as floating matter.

This floating matter atop the molten bath frequently becomes adhered to the underside of the glass ribbon advancing over the bath to soil the glass, or again, the floating matter moves along with the movement of the glass ribbon towards the exit of the bath to become accumulated at the exit end where it scratches the surface of the glass and hence degrades the quality of the product. Hence, for preventing the accumulation of such floating matter in neighborhood of the exit, it becomes necessary to remove it to the outside of the bath.

The object of this invention is to provide for the manufacture of sheet glass of good quality by eliminating the floating matter from the molten metal bath employed in the manufacture of the glass ribbon. The foregoing object is achieved by the following invention device by which floating matter which floats atop the molten metal bath is trapped.

The invention device for trapping floating matter which floats atop the molten metal bath in a glass ribbon manufacturing apparatus which advances the glass over a bath of molten metal has at least one pocket provided in the neighborhood of the exit to said molten metal bath and adjacent thereto, it being separated from the bath :by means of a partition, the top of which, in at least a part thereof, being lower than the level of molten metal and that part submerged in the molten metal having an opening through which the molten metal can pass.

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Referring to the accompanying drawings, FIG. 1 is a plan view of one embodiment of this invention, FIG. 2 being a side view in vertical section taken along line A-A of FIG. 1, FIG. 3 being a partially magnified view of FIG. 1, FIG. 4 being a side view in vertical section taken along line BB' of FIG. 3, and FIGS. 5 and 6 being side views in cross-section taken along respective lines CC and D-D of FIG. 3.

In FIGS. 1 to 6, molten glass 1 flows from a forehearth 2 of the melting furnace down a lip-tile 3 to become a glass ribbon 4 which then advances over a molten metal bath 5. The glass ribbon which has been cooled and sufliciently solidified then leaves the molten metal bath and is conveyed by means of a roller conveyor 6.

The device comprising a pocket 8 and a partition 9 adapted to trap matter which floats atop the molten metal bath is provided in both side walls of the bath at a position adjacent to the exit 7 of the bath. Pocket 8 of the molten metal bath is defined by a floor 11, which is an extension of floor 10 of the bath, a side wall 13 which continues from a side wall 12 of the aforesaid bath, a side wall 15, which continues or extends from an exit wall 14 of the bath, a ceiling 17, which extends from a ceiling 16 of the bath, and an end wall 18 interconnecting said side walls 13 and 15. Partition 9 separates the molten metal bath 5 and the pocket 8 of the bath. The upper part of the partition at a part 19 thereof near the exit of the molten metal bath is made to be little lower than the level of the molten metal so as to permit the floating matter of the main bath 5 to overflow into the pocket 8. Further, the partition has in that part which is submerged in the molten metal an opening 20 by which the molten metal can pass into the main bath 5 from the pocket 8. An opening 21 is disposed between the end wall 18 and the ceiling 17, and the top edge of the end wall 18 is inclined downwardly towards the pocket.

The molten metal near the surface of the bath advances towards the exit of the bath along with the advancing glass ribbon and hits the exit wall of the bath, a part becoming a surface stream which flows along the exit wall and passes over the part 19 to How into the pocket of the molten metal bath. A major portion of the floating matter which floats atop the molten metal bath rides this stream which heads towards the pocket to become trapped therein. The molten metal which has entered the pocket passes through the opening 20 of the partition and returns to the main bath. The floating matter which has once been trapped in the pocket does not return to the bath and hence gradually accumulates in the pocket. Before the pocket becomes full of the floating matter, it is skimmed out from the opening 21 via the top edge of the end wall.

To ensure that only the molten metal stream of the surface of the molten metal bath which carries the floating matter enters the pocket of the bath effectively, the upper part of the partition in at least a part thereof is made slightly lower than the surface of the molten metal bath, but since the stream that proceeds towards the pocket is the faster the nearer it is to the bath exit, it is preferred that the upper part of the partition at that part thereof which is nearest to the bath exit is made lower, as shown in the drawings. On the other hand, in order that the stream which passes through the opening in the partition and returns to the main bath does not interfere with the stream which enters the pocket, the opening in the partition should preferably be provided at a location which is as far away as possible from that part of the upper part of the partition which is made lower. For this purpose, the length of the pocket 8 longitudinally of the molten metal bath should preferably be made as great as possible.

While a wide variety of refractory materials can be employed for the partition, steel whose surface has been impregnated with aluminum can also be used, since its mechanical and chemical strength are great.

bath is disposed is not restricted to the position at the two side walls of the bath adjacent tothe exit thereof, as shown in the embodiment presented, but may be at any position so long as it is in the neighborhood of the bath exit. For instance, it may be disposed in the exit wall.

If the device of this invention is employed, it becomes very easy to trap and remove the floating matter which floats atop the molten metal bath in the process which employs such a bath in the manufacture of glass ribbons, in consequence of which sheet glass not having surface defects can be obtained.

What is claimed is:

1. An apparatus for manufacturing glass ribbons by advancing the glass over a bath ofmolten metal, comprising a main bath of molten metal means forming at least one pocket having floor, sidewalls, and end walls to receive molten metal from said main bath and floating matter which collects atop said molten metal, said pocket connected juxtaposed to said main bath in the area of the exit thereof; means defining an opening in one of said pocket walls for taking out the floating matter which has collected in said pocket; and a static partition which separates said main bath from said pocket having an upper edge part extending above the surface of said molten metal and having a lower edge part submerged in the molten metal bath; a portion of the upper edge part of said partition being lower than the level of the molten metal so as to facilitate the flow of the molten metal near the surface of the main bath into said pocket together with said floating matter, so that said metal and said floating matter pass atop said lower edge part which is disposed lower than the level of the main bath, and said static partition is provided with an opening, below said upper edge part and adjacent said submerged part, wherethrough the molten metal can pass back into the main bath while said floating matter is trapped in said pocket.

2. An apparatus for manufacturing glass ribbons by advancing the glass over a bath of molten metal, comprising means forming a main bath having a floor, or ceiling, side walls and end walls, one end wall being an exit wall; means forming two pockets to receive molten metal from the molten metal bath; said pockets disposed one each on both sides of said bath at the exit end thereof and adjacent to said main bath; said pockets each being defined by a first side wall projecting transversely from the side wall of-the main bath, a second side wall continuing from the exit wall of the main bath; an end wall interconnecting said first and second side walls; a pocket floor extending from the floor of the main bath, a pocket ceiling extending from the ceiling of the main bath, said floor and ceiling of the pocket interconnecting with the pocket Walls; means defining an opening being provided between said ceiling and said end wall of the pocket for taking out the floating matter which has accumulated in said pocket; static partitions in said molten metal which separate said main bath from and help define each of said pockets, said partitions having an uneven upper edge, a first part of said edge of each of said partitions is above and a second part is below the level of the molten metal as to facilitate the flow of the molten metal, near the surface of the main bath, into said pocket together with said floating matter after passing atop said second part of said upper edge which is lower than the level of the main bath, said static partitions being each provided with an opening below said first part which is above the bath level and offset from said second part submerged in the molten metal, wherethrough the molten metal can pass back into the main bath while said floating matter is trapped in said pocket.

3. A device according to claim 2 wherein the upper edge of the end wall of said pockets is inclined downwardly towards the inside of the bath.

4. A device according to claim 2 wherein said static partitions are lateral of and parallel to the flow of the main metal bath.

5. A device according to claim 2 wherein said static partitions are lateral of and parallel to the flow of the main metal bath; and wherein said second part of the upper edge of said static partitions is disposed downstream of the flow, and said opening below said first part of said static partitions is disposed upstream of said downstream second part.

References Cited UNITED STATES PATENTS 3,389,983 6/1968 Robinson et al. -182 s. LEON BASHORE, Primary Examiner E. R. FREEDMAN, Assistant Examiner US. 01. X.R. 6527, 65, 99, 182

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