Method for cooling a moving metal belt

Abstract

The present invention relates to a method for cooling a moving metal belt ( 2 ) in a continuous processing line by spraying a gas, a liquid, or a mixture consisting of gas and liquid onto the belt, the processing line including a cooling section ( 1 ) followed by a downstream section ( 4 ), the inlet ( 4 a ) of the downstream section corresponding to the outlet ( 1 b ) of the cooling section, wherein according to said method: the change in the temperature cross-section of the belt between the inlet ( 4 a ) and the outlet ( 4 b ) of the downstream section ( 4 ) is evaluated; the temperature cross-section suitable for the inlet of the downstream section is deduced, on the basis of a desired temperature cross-section at the outlet of the downstream section ( 4 ), in order to obtain the desired cross-section at the outlet; and the cooling capacity of the cooling section ( 1 ) is adjusted according to the width of the belt and over the length of the cooling section, while taking into the account the temperature cross-section of the belt at the inlet of the cooling section, so that the cooling makes it possible to obtain the aforementioned temperature cross-section at the outlet of the cooling section.

1 . A method for cooling a moving metal strip in a continuous processing line by spraying a gas, a liquid, or a mixture consisting of gas and liquid onto the strip, the processing line comprising a cooling section followed by a downstream section having a thermal effect upon the strip, the inlet of the downstream section corresponding to the outlet of the cooling section, wherein:
 the change in the transverse temperature profile of the strip between the inlet and the outlet of the downstream section is determined in real time by means of a computer on the basis of mathematical models, while taking into account the format of the strip, the running speed of the strip, the transverse temperature profile of the strip at the inlet of the downstream section, and the development of the heat exchanges between the strip and its environment in the downstream section,   on the basis of a desired transverse temperature profile at exit from the downstream section, the transverse temperature profile at the inlet of the downstream section is suitable for obtaining the desired exit profile,   the cooling capacity of the cooling section is regulated according to the width of the strip and over the length of the cooling section in real time by a control and operating system of the line, by means of the computer, on the basis of mathematical models, while taking into account the transverse temperature profile of the strip at the inlet of the cooling section and the development of the heat exchanges between the strip and its environment in the cooling section, so that the cooling makes it possible to obtain the aforementioned suitable transverse temperature profile at exit from the cooling section.   
     
     
         2 . The method as claimed in  claim 1 , wherein the adjustment of the cooling capacity is obtained by splitting a cooling device into a plurality of units along the width and along the length of the cooling section. 
     
     
         3 . The method as claimed in  claim 2 , wherein each unit is provided with regulating members in order to vary its cooling capacity independently from the other units. 
     
     
         4 . The method as claimed in  claim 3 , wherein the operation of the regulating members is carried out from the computer, in which is installed an appropriate operating program for the cooling units. 
     
     
         5 . The method as claimed in  claim 4 , wherein the computer receives data supplied by temperature sensors distributed in the cooling section and by temperature sensors distributed in the downstream section, and the computer, on the basis of these data, checks whether the cooling is effected in the desired manner, and possibly corrects the execution of the cooling according to the width of the strip and according to its length in order to obtain the desired profile.