Method and apparatus for heating a workpiece

Claim 3

A method of heating a steel strip according to claim 1 in which the strip is given a second preheat by passing it through said waste gases flowing from said heating chamber to said recuperator.

Claim 4

Apparatus for heating a workpiece which comprises an elongated main furnace section having a main heating chamber through which the workpiece passes from an entry to an exit end; fuel burners in said main furnace structure; an opening at the entry end of said heating chamber for receiving said workpiece and waste gases from the combustion of said fuel; a jet recuperator at the entry end of said main section having a heating chamber communicating with said main heating chamber and through which the workpiece passes to said heating chamber in said main furnace section, said recuperator including a waste gas chamber communicating with said main heating chamber and having a wall adjacent the path of travel of said workpiece in said recuperator heating chamber with holes therethrough, outlet means from said recuperator heating chamber offset transversely from the center thereof intermediate the length thereof, fan means for receiving waste gases from said main furnace section and said recuperator heating chamber through said offset outlet and delivering them through said waste gas chamber and said holes against said workpiece; and means for moving said workpiece through said heating chambers and exit end of said main furnace section.

Claim 5

Apparatus for heating a workpiece which comprises an elongated main furnace section having a main heating chamber through which the workpiece passes from an entry to an exit end; fuel burners in said main furnace structure; an opening at the entry end of said heating chamber for receiving said workpiece and waste gases from the combustion of said fuel; a jet recuperator at the entry end of said main section having a heating chamber communicating with said main heating chamber and through which the workpiece passes to said heating chamber in said main furnace section, said recuperator including a waste gas chamber communicating with said main heating chamber and having a wall adjacent the path of travel of said workpiece in said recuperator heating chamber with holes therethrough, outlet means from said recuperator heating chamber offset transversely from the center thereof intermediate the length thereof, fan means for receiving waste gases from said main furnace section and said recuperator heating chamber through said offset outlet and delivering them through said waste gas chamber and said holes against said workpiece; and means for moving said workpiece through said heating chambers and exit end of said main furnace section.

Claim 6

Apparatus according to claim 3 in which said workpiece travels in a generally horizontal path, said recuperator heating chamber is rectangular in transverse section, and said apparatus includes a pair of outlet means from said recuperator heating chamber, each offset transversely from the center thereof one at one side and the other at the other side of said center and each intermediate the length of said recuperator.

Claim 7

Apparatus according to claim 4 in which said recuperator includes two waste gas chambers one below and one above said heating chamber, a top metal wall for the lower waste gas chamber, a bottom metal wall for the upper waste gas chamber, side walls for said recuperator heating chamber, one of said outlet means in each of said side walls intermediate the length thereof, each of said top and bottom walls having a plurality of holes therethrough spaced over the majority of the surface thereof, and fan means on the outside of each of said side walls for receiving waste gases from said main furnace section and said recuperator heating chamber through the associated outlet and delivering them through said waste gas chamber and said holes against said workpiece, a portion of said waste gases then passing from the entry end of said recuperator.

Claim 8

Apparatus according to claim 5 including a discharge opening for said workpiece at the exit end of said furnace only slightly larger than said workpiece.

Claim 9

Apparatus according to claim 5 including an elongated intermediate furnace section between the main furnace section and said recuperator, and a heating chamber in said intermediate section for receiving said waste gases from said main furnace section and delivering them to said recuperator, said intermediate section being heated solely by said waste gases.

Claim 10

Apparatus according to claim 7 including a discharge opening for said workpiece at the exit end of said furnace only slightly larger than said workpiece.

Claim 11

Apparatus according to claim 3 including an elongated intermediate furnace section between the main furnace section and said recuperator, and a heating chamber in said intermediate section for receiving said waste gases from said main furnace section and delivering them to said recuperator, said intermediate section being heated solely by said waste gases.

Claim 12

Apparatus according to claim 3 including a second jet recuperator at the entry end of said first jet recuperator having a construction similar to said first jet recuperator, and means for delivering said waste gases from said first recuperator to said second recuperator.

Claim 13

Apparatus according to claim 10 in which said workpiece travels in a generally horizontal path and each of said recuperators includes two waste gas chambers one below and one above said heating chamber, a top metal wall for the lower waste gas chamber a bottom metal wall for the upper waste gas chamber, side walls for said recuperator heating chamber, outlet means in each of said side walls intermediate the length thereof, each of said top and bottom walls having a plurality of holes therethrough spaced over the majority of the surface thereof, and fan means on the outside of each of said side walls for receiving waste gases from said main furnace section and said recuperator heating chamber through the associated outlet means and delivering them through said waste gas chamber and said holes against said workpiece.

Claim 14

Apparatus according to claim 11 including an elongated intermediate furnace section between the main furnace section and said first recuperator, and a heating chamber in said intermediate section for receiving said waste gases from said main furnace section and delivering them to said first recuperator, said intermediate section being heated solely by said waste gases.

Claim 15

Apparatus according to claim 12 including a discharge opening for said workpiece at the exit end of said furnace only slightly larger than said workpiece.

Claim 16

Apparatus according to claim 3 including a discharge opening for said workpiece at the exit end of said furnace only slightly larger than said workpiece.