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Selective Roll Cooling Systems and Valves

Overview


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Irregular and asymmetrical rolling loads across the work roll cause a non uniform transverse temperature distribution. Hot zones on the roll lead to an increase in the roll diameter in those particular areas, changing the transverse profile and crowning of the roll barrel, when the heat affected roll profile (thermal profile) is transferred to the material; the profile and flatness in the strip is immediately degraded.


The Selective cooling header is used in conjunction with a shape sensing device such as a Shape-roll / Measuring-roll, the Selective Roll Cooling configuration being dimensioned to exactly match the pitch of the shape metering roll segments (sensors).


To achieve controlled selective cooling, the work roll barrel is cooled by dedicated banks of spray nozzles uniformly spaced across its width precisely aligned to stress-measuring sensors (segments or rotors) on the shape roll. Every nozzle and valve assembly is controlled by a solenoid valve receiving the electrical signal through an I/O unit from the shape meter control computer.


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LechlerDE-Shop:/images/lg.gif Selective Roll Cooling Systems (PDF)

   Typical Selective Roll Cooling System Configuration

   

As a zone on the work roll expands through heat, the corresponding section of the strip is reduced in thickness (over-rolled) and elongated proportionally throughout its length. However as that section is constrained by shorter zones, a buckle (wave or pocket) is generated.

 

LechlerDE-Shop:/images/02_produkte/huettentechnik/selective_roll_cooling_bild2.jpg    

The buckled zones exhibits a lower stress than the shorter zones which is measured by the sensors in that zone on the shape roll.

Each of the zoned spray banks can be operated independently to cool the "hot zone" on the roll body that has expanded in diameter, effectively reducing its actual diameter and eliminating the "over-rolling that has resulted in that corresponding zone on the strip.

Typical Irregular Longitudinal Elongation

 

 

The Shape-roll roll comprises of an array of circular segments or rotors each housing several radial mounted stress measuring sensors ; typically a 26mm or 52mm pitch measuring the stress across the strip width as the strip (under tension) passes over the Shape-roll.


Each coolant valve / nozzle (spray) is controlled by feedback from a corresponding stress sensor on the shape roll or any other shape control system.

LechlerDE-Shop:/images/02_produkte/huettentechnik/selective_roll_cooling_bild3.jpg     LechlerDE-Shop:/images/02_produkte/huettentechnik/selective_roll_cooling_bild4.jpg
Typical SELECTOSPRAY® System
Typical SELECTOSPRAY® Roll Cooling Principle

 

The selective cooling (SELECTOSPRAY® System) can also be controlled manually by the operators, semi automatically by a PLC, or automatically (closed loop) in conjunction with a shape control system.

 

LechlerDE-Shop:/images/02_produkte/huettentechnik/teaser/Teaser Spritzbalken.jpg One of the most critical variables to a successful production equation is the roll cooling system. A system that works well can make a huge contribution to the life of the rolls and controll of the final surface and shape. Properly designed roll cooling headers ensure precise application of coolant for optimal heat removal from the rolls and proper lubrication of the rolls takes place. Whether the operation is a single stand, reversing, or tandem mill, Lechler's engineers will work with you to analyze your application, and will provide sound recommendation to satisfy your mill needs.

 

SELECTOSPRAY® Headers    
   
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  • Custom header designs
  • Fabricated Standard Plate Design
  • Robust Stainless Steel Machined forging
    construction where required
  • Utilization of the latest 3D Modeling Software

  • Flow rates and spray angles are designed along with the positioning of the headers
  • Headers supplied will have top and bottom symmetrical cooling in a mill stand
  • Engineered and fabricated for all Rolling Environments  






SELECTOSPRAY® Control Cabinet



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  • Cabinet designs are dictated by the
    type of valves
  • All Cabinets are built to a custom design
  • Cabinets are all manufactured 100% in-house
    by Lechler
  • Hardwired from remote I/O

  • Wago I/O unit is optional
  • Interfaces with Profibus / Interbus / Foundation Fieldbus etc… digital interfaces
  • HMI consoles for more sophisticated functions are available






SELECTOSPRAY® Pneumatic Air Hoses



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  • Robust stainless steel braid with air lines enclosed
    in an inner SS convoluted shell
  • Pneumatic Hoses made for the Modulax and
    Mini Modulax Valves
  • Types: 21way, 30way, 44way
  • 3mm air lines for 21way

  • 4mm air lines for 30way and 44way
  • IP67 Hose end rating
  • Key locating fixtures ensuring correct hose alignment
  • Custom made Lechler Product






SELECTOSPRAY® Electrical Hoses



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  • Robust stainless steel braid with electrical lines
    enclosed in an inner SS convoluted shell
  • Quick release couplings on the headers and
    control cabinets
  • Electrical Hoses made for the MEV, EVA and
    Mini EVA valves

  • Range:  2 up to 108 electrical cables
  • IP67 hose end rating
  • Key locating fixtures ensuring correct hose alignment
  • Custom made Lechler Product






SELECTOSPRAY® Mini EVA Valve: 961.EVA.MM.CS.00.0



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  • Minimum horizontal pitch – 1inch
  • Retractable from the front of header for ease
    of maintenance
  • Speed response time – 20ms open / 15ms close

  • Stainless Steel design for long life and robust operation
  • Max operating Temperature – 250 degrees F






SELECTOSPRAY® EVA Valve: 961.EVA.00.QC.NB.0



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  • Minimum horizontal pitch – 2inch
  • Retractable from the front of the header for ease of maintenance
  • Speed response time – 20ms open / 15ms close

  • Stainless Steel design for long life and robust operation
  • Max operating Temperature – 250 degrees F






SELECTOSPRAY® Modulax Valve: 987.403.16.00.01.1



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  • Minimum horizontal pitch – 2inches
  • Modulax valves have a 2:1 liquid / air pressure ratio
  • Valve consists of 1 moving part

  • Pneumatic actuation
  • Self aligning nozzles
  • Solenoid valves located remotely from mill





SELECTOSPRAY® Modulax Valve Rear Exhaust: 961.REX.16.00.00.0



LechlerDE-Shop:/images/02_produkte/huettentechnik/SELECTOSPRAY_Modulax_Valve_Rear_Exhaust_T.jpg
  • Minimum horizontal pitch – 2inches 
  • Modulax valves have a 2:1 liquid / air pressure ratio
  • Valve consists of 1 moving part 

  • Pneumatic actuation 
  • Self aligning nozzles 
  • Solenoid valves located remotely from mill






SELECTOSPRAY® Mini Modulax Valve: 961.000.00.MM.00.0



LechlerDE-Shop:/images/02_produkte/huettentechnik/SELECTOSPRAY_Mini_Modulax_Valve_T.jpg
  • Minimum horizontal pitch – 1 inch
  • Modulax valves have a 2:1 liquid / air pressure ratio
  • Valve consists of 1 moving part

  • Pneumatic actuation
  • Self aligning nozzles
  • Solenoid valves located remotely from mill







LechlerDE-Shop:/images/lg.gif Selective Roll Cooling Systems (PDF)