Method and apparatus for cooling the rollers of a roll stand

Abstract

To accomplish the object of providing a method of and an apparatus for optimally cooling the rolls of a roll stand, where energy considerations, such as the minimization of necessary cooling fluid flow and cooling fluid pressure, and incident design and manufacturing costs, must be taken into account, the invention proposes that the rolls are cooled with a combination of high- and low-pressure cooling.

1 . A method of cooling rolls of a roll stand with a low-pressure cooling system with a cooling shell that directs a low-pressure cooling fluid against the roll,
 wherein   the rolls are simultaneously cooled with a high-pressure cooling system that sprays a coolant fluid directly under high pressure against the roll, and   the low-pressure cooling system comprises a plurality of hinged-together cooling shell segments.   
     
     
         2 . (canceled) 
     
     
         3 . The method according to  claim 1 , wherein about 20% of the cooling fluid is fed to the high-pressure cooling system and about 80% of the entire amount of cooling fluid is fed to the low-pressure cooling system to produce the main cooling effect. 
     
     
         4 . The method according to  claim 1 , wherein with the aid of a process model, a cooling fluid pressure range for the low-pressure cooling system of preferably between 0.5 to <5 bar and for the high-pressure cooling system of between 5-50 bar is set depending on the rolling parameters of thickness reduction, specific surface pressure in the roll gap, rolling speed, strip temperature, roll material and rolled material. 
     
     
         5 . The method according to  claim 1 , wherein the low-pressure cooling system is a low-pressure spray cooling, a low-pressure cooling curtain, a low-pressure flow cooling, or a high-turbulence low-pressure cooling, or a combination of these types of cooling, where with the low-pressure flow cooling the cooling fluid flows in a gap between the roll outer surface and at least one cooling-shell segment that is juxtaposed with one of the separate regions of the roll surface. 
     
     
         6 . The method according to  claim 5 , wherein the position of the cooling shell segment is adjusted according to the roll diameters or roll positions in order to generate a reproducible cooling effect. 
     
     
         7 - 8 . (canceled) 
     
     
         9 . The method according to one of  claim 5  characterized, wherein primarily a tangential coolant flow along the surface of the rolls is produced by the cooling shells or a coolant flow or coolant discharge is produced to the side by spacer plates or spacer strips that seal tangentially so that the roll next to the strip can be heated by heated cooling fluid in the center. 
     
     
         10 . The method according to  claim 9 , wherein in a preferred coolant discharge parallel to the roll axis the coolant feed is blocked next to the strip by zone cooling next to the cooling shell spaced from the roll or from the coolant feed channel. 
     
     
         11 . (canceled) 
     
     
         12 . The method according to  claim 1 , wherein the cooling intensity of the low-pressure cooling system, in particular convection cooling, is adjusted variably over the length of the rolls. 
     
     
         13 - 15 . (canceled) 
     
     
         16 . The method according to  claim 1 , wherein the spray nozzle bars of the high-pressure cooling system, which are optionally moveable in the width direction, are used for zone cooling and are designed to direct the cooling fluid at the desired region of the roll with directed flow axially by electric or hydraulic motors with threaded rods or by a hydraulically moved single- or multipart linkage mechanism with spray nozzle bar sections or rotatable nozzle units fastened thereto. 
     
     
         17 - 19 . (canceled) 
     
     
         20 . The method according to  claim 1 , wherein a computational model is used which fulfills the following objectives:
 adjustment of the amount of coolant and the pressure level for the low-pressure and the high-pressure section depending on the decrease in strip thickness, specific surface pressure in the roll gap, the roll speed, strip temperatures, roll material and rolled material, and depending on the measured or calculated roll temperatures or observed roll surface and is also dependent on the coolant impingement width setting,   adjustment of the amount of coolant across the width of the strip by adjusting the outlet openings of the feed channel or adjusting the gap width between the cooling shell and the working roll depending on the strip width or adjustment of the position of the spray nozzle bar sections that can move in the width direction, or depending on the measured profile and flatness condition across the width of the strip, and   establishment of the tilt position of the cooling bar support and of the cooling shell application position using the cylinder, optionally using the pressure signals and path transducer signals.   
     
     
         21 . (canceled) 
     
     
         24 . A cooling apparatus for cooling the rolls of a roll stand with a low-pressure cooling system that directs a low-pressure cooling fluid against the rolls, wherein,
 in addition to the low-pressure cooling system a high-pressure-cooling system is provided that is provided with spray tubes and nozzles for spraying the rolls directly with a cooling liquid under high pressure simultaneously with the low-pressure cooling of the low-pressure cooling system.   
     
     
         25 . The cooling apparatus according to  claim 24 , wherein the low-pressure cooling system is designed to produce low-pressure spray cooling, a low-pressure cooling curtain, highly turbulent low-pressure cooling or a combination of these cooling types. 
     
     
         26 . The cooling apparatus according to  claim 25 , wherein for producing low-pressure flow cooling the low-pressure cooling system has at least one cooling shell with at least one preferably arcuate cooling-shell segment that forms with the outer surface of the roll to be cooled a space foldable with the flowing cooling fluid and that is movable to adjust the gap width of the spacing between the roll surface and the cooling shell. 
     
     
         27 . The cooling apparatus according to  claim 24 , wherein the high-pressure cooling system as a one or multiple-row spray-nozzle beam with nozzles for high-pressure cooling the rolls. 
     
     
         28 . (canceled) 
     
     
         29 . The cooling apparatus according to  claim 24 , wherein in the combined low/high-pressure cooling system the spray nozzle bars of the high-pressure cooling system are mounted above or below or within the low-pressure cooling system in a fixed fashion or moveably in the width direction. 
     
     
         30 . The cooling apparatus according to  claim 24 , wherein two or more of the cooling-shell segments are movably connected to one another. 
     
     
         31 . The cooling apparatus according to  claim 24 , wherein the moveable connection between the cooling shell segments is designed in the form of a hinge or a spring or an elastic connection or a multipart linkage mechanism. 
     
     
         32 - 35 . (canceled) 
     
     
         36 . The cooling apparatus according to  claim 24 , wherein at least one of the cooling shell segments, such as the center segment, can be positioned in front of the roll using the cooling bar support and the other cooling shell segments can be pressed against the roll separated by spacer plates using springs. 
     
     
         37 . (canceled) 
     
     
         40 . The cooling apparatus according to  claim 24 , wherein a space is formed between the cooling shells or cooling shell segments and the roll surfaces using a sealing function or a sealant and by a predetermined pressure against the rolls, wherein very little cooling fluid is able to escape from the space to the environment. 
     
     
         41 - 42 . (canceled) 
     
     
         43 . The cooling apparatus according to  claim 24 , wherein the high-pressure cooling system is on the outlet side of the stand. 
     
     
         44 . (canceled)