Method and device for dynamically supplying coolant to a cooling device for cooling metal strip or other rolled stock

Abstract

The present invention relates to a method of dynamically supplying coolant to a cooling device, in particular at least one spray bar, for cooling metal strip or other rolled stock. According to the method, a pre-accelerated stream of coolant is provided, which passes by the cooling device ( 1 ) and is fed into a return ( 3 ). Furthermore, the presence and/or the temperature of a metal strip or other rolled stock to be cooled is monitored and, dependent on the presence and/or the temperature of the metal strip or the other rolled stock, the stream of coolant is diverted to the cooling device ( 1 ), wherein, instead of passing by the cooling device ( 1 ) and being fed into a return ( 3 ), the stream of coolant is fed to the cooling device ( 1 ) for cooling the metal strip or the other rolled stock. The present invention also comprises a corresponding device for carrying out the method.

1 . A method of dynamically supplying coolant to a cooling device ( 1 ,  1 ′), in particular to at least one spray bar ( 1 ,  1 ′) for cooling a metal strip or a similar rolled stock with the coolant, comprising the steps of:
 a) Providing a pre-accelerated coolant flow, wherein the coolant flow by-passes the cooling device ( 1 ,  1 ′) and is delivered to a return line ( 3 ); 
 b) monitoring presence and/or temperature of the to-be-cooled metal strip or the similar rolled stock; 
 c) diverting the already pre-accelerated coolant flow to the cooling device ( 1 ,  1 ′) dependent on the presence and/or predetermined temperature of the metal strip or the similar rolled stock so that the coolant flow instead of by-passing the cooling device and being delivered to the return line, is fed, being already pre-accelerated, to the cooling device ( 1 ,  1 ′) for cooling the metal strip or the similar rolled stock. 
 
     
     
         2 . A method according to  claim 1 , wherein the pressure loss of the coolant stream at by-pass of the cooling device ( 1 ,  1 ′) and the pressure loss of the coolant stream at feeding of the coolant stream to the cooling device deviate from each other by less than 20%, or are essentially the same, so that pressure surges, at the deviation of the already accelerated coolant stream, toward the cooling device ( 1 ,  1 ′) are prevented. 
     
     
         3 . A method according to  claim 1 , wherein for minimizing the path between the deviation location of the coolant flow and the outlets of the cooling device ( 1 ,  1 ′), the deviation of the coolant stream takes place at less than 5 m, preferably at less than 3 m upstream of the outlets of the cooling device ( 1 ,  1 ′). 
     
     
         4 . A method according to  claim 1 , wherein a to-be-deviated volume flow of the coolant amounts to more than 150 m3/h and, preferably, to more than 400 m3/h. 
     
     
         5 . A device for cooling a metal strip, comprising:
 a cooling device for cooling a metal strip or a similar rolled stock and having at least one spray bar ( 1 ,  1 ′) with coolant outlets for applying the coolant to the metal strip;   conduit means ( 2 ,  20 ,  20 ′) for conducting a coolant flow from a coolant source ( 4 ) to the spray bars ( 1 ,  1 ′);   by-pass means for conducting the coolant flow from the conduit means ( 2 ,  20 ,  20 ′) to a return line ( 3 );   switchable deflection means ( 5 ,  50 ,  50 ′) formed for switchingly conducting the coolant flow through the conduit means ( 2 ,  20 ,  20 ′) to the spray bars ( 1 ,  1 ′) or for deviating the coolant flow from the conduit means ( 2 ,  20 ,  20 ′) into the by-pass means.   
     
     
         6 . A device according to  claim 5 , wherein the cooling device has at least one valve ( 9 ) for controlling the volume flow of the coolant flow that flows through the conduit means, wherein the deflection means ( 5 ,  50 ,  50 ′) is downstream of the control valve ( 9 ). 
     
     
         7 . A device according to  claim 5 , wherein the switchable deflection means ( 5 ,  50 ,  50 ′) comprises either at least one switchable valve for conducting the coolant flow to the spray bars ( 1 ) or by-pass means, and/or wherein the switchable deflection mans ( 5 ,  50 ,  50 ′) carries out a switching process in less than 5 sec, preferably in less than 1.5 sec. 
     
     
         8 . A device according to  claim 5 , wherein the conduit means ( 2 ,  20 ,  20 ′) comprise a pump ( 11 ,  11 ′) for increasing an available, from the source, coolant volume flow. 
     
     
         9 . A device according to  claim 8 , wherein the coolant flow by-passes the pump ( 11 ,  11 ′) through a by-pass ( 13 ). 
     
     
         10 . A device according to  claim 5 , wherein a plurality of spray bars ( 1 ), preferably maximum ten spray bars ( 1 ) are assembled in a first cooling group ( 10 ) and the first conduit means ( 20 ) feeds the coolant to the first cooling group ( 10 ), and at most three spray bars ( 1 ) of the first cooling group ( 10 ) are provided with switchable deflection means ( 50 ) for conducting the coolant flow from the first conduit means ( 20 ) in the return line, so that cooling flow from at most three spray bars ( 1 ) of the first cooling group ( 10 ) is deviated into the by-pass means independent from the remaining spray bars of the first cooling group ( 10 ). 
     
     
         11 . A device according to  claim 10 , wherein additionally a plurality of further spray bars ( 1 ′), preferably maximum ten spray bars ( 1 ′) are assembled in a second cooling group ( 10 ′) and the second conduit means ( 20 ′) feeds the coolant to the second cooling group ( 10 ) and at most three spray bars ( 1 ′) of the second cooling group ( 10 ′) are provided with switchable deflection means ( 50 ) for conducting the coolant flow from the second conduit means ( 20 ′) in the return line, so that cooling flow from at most three spray bars ( 1 ′) of the second cooling group ( 10 ′) is deviated into the by-pass means independent from the remaining spray bars ( 1 ′) of the second cooling group ( 10 ′). 
     
     
         12 . A device according to  claim 11 , wherein the first and second groups ( 10 ,  10 ′) are separately supplied with coolant from the source ( 4 ). 
     
     
         13 . A device according to  claim 11 , wherein a separate pump ( 11 ,  11 ′) increases the volume flow to each of separate cooling group ( 10 ,  10 ′). 
     
     
         14 . A device according to  claim 5 , wherein the device comprises a plurality of spray bars ( 1 ), and maximum three of the spray bars ( 1 ) are associated, separately from further spray bars ( 1 ) with a respective deflection means ( 5 ), so that maximum three spray bars ( 1 ) either are fed with the pre-accelerated coolant via the conduit means ( 2 ), or the coolant flow is fed to by-pass means by deflection means ( 5 ) associated with the maximum three spray bars ( 1 ); or in particular each spray bar ( 1 ) is associated with the switchable deflection means ( 5 ) separately from the further spray bars ( 1 ) so that either the pre-accelerated coolant flow is fed to each spray bar by the conduit means ( 2 ) m , or deflection means ( 5 ) associated with each spray bar ( 1 ) feeds the coolant flow to the by-pass means. 
     
     
         15 . A device according to  claim 5 , wherein at least one of the spray bars ( 1 ) is supported by a support device, and the switchable deflection means ( 5 ) is mounted on the support device; and/or wherein the switchable deflection means ( 5 ) is located by less than 5 m upstream of the spray bar ( 1 ).