Method for heating lightweight metal ingots

Abstract

A method is described for heating lightweight metal ingots ( 1 ), with the lightweight metal ingots ( 1 ) being heated in a furnace ( 2 ) by hot burner exhaust gases. In order to provide advantageous heating conditions it is proposed that the lightweight metal ingots ( 1 ), prior to their heating in the furnace ( 2 ), are preheated via at least one preheating apparatus ( 9 ) which rests in a planar manner thereon and is supplied by a fluid heat carrier which is heated in heat exchange by the hot exhaust gases from the furnace ( 2 ) and is guided in a circuit ( 7 ).

1 . A method for heating lightweight metal ingots, with the lightweight metal ingots being heated in a furnace by hot burner exhaust gases, wherein the lightweight metal ingots ( 1 ), prior to their heating in the furnace ( 2 ), are preheated via at least one preheating apparatus ( 9 ) which rests in a planar manner thereon and is supplied by a fluid heat carrier which is heated in heat exchange by the hot exhaust gases from the furnace ( 2 ) and is guided in a circuit ( 7 ). 
     
     
         2 . An apparatus for heating lightweight metal ingots, comprising a furnace heated via burners and a heat exchanger which is supplied with the hot exhaust gases of the furnace, wherein the heat exchanger ( 6 ) and a preheating device ( 9 ) which accommodates the lightweight metal ingots ( 1 ) in planar contact are disposed in a heat carrier circuit ( 7 ) for a fluid heat carrier. 
     
     
         3 . An apparatus according to  claim 2 , wherein the preheating device ( 9 ) comprises a frame ( 11 ) with a contact surface ( 13 ) for the lightweight metal ingots ( 1 ) and a heat transfer plate ( 10 ) which extends transversally to the contact surface ( 13 ), which forms a contact area ( 15 ) for the lightweight metal ingots ( 1 ) and through which the heat carrier flows. 
     
     
         4 . An apparatus according to  claim 3 , wherein the heat transfer plate ( 10 ) is composed of two layers ( 16 ,  17 ) which form at least one flow conduit ( 18 ) for the heat carrier between themselves. 
     
     
         5 . An apparatus according to  claim 4 , wherein the layer ( 16 ) of the heat transfer plate ( 10 ) forming the contact area ( 15 ) is subdivided into individual fields by grooves ( 22 ) forming bending points. 
     
     
         6 . An apparatus according to  claim 3 , wherein the heat transfer plate ( 10 ) is resiliently supported on the side facing away from the contact area ( 15 ). 
     
     
         7 . An apparatus according to  claim 3 , wherein the contact surface ( 13 ) of the frame ( 11 ) for the lightweight metal ingots ( 1 ) slopes towards the contact area ( 15 ). 
     
     
         8 . An apparatus according to  claim 7 , wherein the contact surface ( 13 ) comprises rollers ( 12 ) with axes which are parallel to the contact surface ( 13 ) and the contact area ( 15 ).