Ironman™ Integral Web Cooling Process System - Megtec

Ironman process unit includes chilled L-wraprollers, steering guide and chilled siliconeapplicator with opposing rollers.Effective evaporative cooling and uniformsilicone application.A cool bead of silicone being applied to theweb by chilled applicator rollers.be reduced but the web is then notsufficiently cooled following the roller,often resulting in increased smokingin the room. Further, there is thena tendency for ink “picking” from thesurface of the printed web which is thendeposited on the roller surface.The Ironman’s small roll diameter of7.5” (180 mm) of the Ironman doesnot allow the creation of a sufficientlyhigh boundary layer at any speed orweb tension. In addition, the surfacetemperature of the L-wrap roller isprecisely controlled to maximize theweb cooling function while solving thecondensation/picking problem. The rollerstays clean from condensate that wouldotherwise cause web marking.No Smoke in the Press RoomConventional dryer/chill systemsallow the formation of visible aerosolscomprised of millions of tiny liquidspheres in the area approximately 0.5 m- 1.0 m after the dryer. The refraction anddiffraction of light through these particlescreates a “smoke effect”. The web exitingthe dryer is still appreciably hot and hasan evaporation rate that enables themoisture in the web to be turned intowater vapor. When that vapor exits theweb and hits the colder atmospheric air,it expands and cools rapidly, condensingto produce the aerosol particle.To counter this physical phenomenon,the web path to L-wrap roller of theIronman is kept very short – lessthan 300 mm - and is fully enclosed.Consequently, the L-wrap roller coolsdown the web before the aerosol creationcan take place.No Marking on RollersAs the web cools and is guided aroundchill rollers and path rollers, there can bea tendency to deposit ink on the surfaceof the rollers, especially rollers which donot turn in precision with the speed of theweb. This can be avoided by two means:elimination of sliding friction by matchingspeed of the roller surface to speed ofthe web, and by applying silicone to theweb to reduce friction. The Ironman usesboth methods in a unique way. The initialL-wrap roller is driven to match the webspeed and eliminate sliding friction. Theweb then passes through the siliconeapplicator that applies silicone fluid toreduce friction throughout the remainingweb path into and through the folder. Allof the chill rollers of Ironman are driven,thereby minimizing the friction betweenthe web and roller surface, thus allowingfor a minimal consumption of siliconewhile eliminating roller marking.Immediately after the first roller siliconeis applied on both sides of the web,protecting the surface and performanceof all rollers further down the path.Without silicone coating an unprotectedink film has a tendency to mark chills andespecially rollers which do not turn inprecision with the speed of the web. Toavoid ink marking the Ironman has drivenrollers; the first roll has a proprietarycoating and is temperature controlled.Robust DesignThe mechanically driven rollers ofthe Ironman allow the use of robustconventional bearings and rotary unions.Furthermore, the silicone applicator islocated further downstream from thefirst L-wrap cooling roller providing lowersilicone roll contact temperatures anddramatically reducing production ofairborne silicone. Less silicone in the airmeans less need to clean this area.The silicone applicator is sealed in ahousing which protects the environmentfrom silicone misting. No silicone mistcan be transported by the dryer into theoxidizer system where silicate could plugthe oxidizer’s heat exchange system.Evaporated water and silicone mistare immediately condensed on thechilled applicator rollers and flow backinto the silicone pans, keeping siliconeconsumption low and increasingmoisture in the web.The cooling feature of the siliconeapplication rollers is patent appliedand ensures that contact between weband roller always has a fluid film. Bymaintaining the fluid film, the rotationof the silicone rollers can be operatedin either direction without any build-upof ink on the roller even at very lowapplication rates.Both silicone applicator rolls always havea constant kiss angle which delivers veryuniform silicone application across theentire web width for all application ratesand at all web steering angles.