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June 09, 2006
Chilled S-Wrap Rollers
Question:
I have a S-wrap configuration that is causing poor film quality because the delta T across the rolls is very high. The temperature varies because the chilled water is too cold. The water flow through the rolls is at a dribble to help the problem but the film heats the water causing the temp across the rolls to increase. Do you recommend chilled water, at what temp? or process water, normally 70 degF?
Michelle Perry
michelle.perry@amcor-Flexibles.com
Reply:
I'm note sure I understand the problem here.
Am I correct to assume the temperature variation is too high across the width of the rollers?
You state the water flow is at a dribble. Wouldn't a high flow rate reduce the temperature variation? At a dribble, it seems you are asking the web to control the roller temperature.
Regarding chilled or 70F water, the lower the temp, but more ability you have to fight the web heat transfer. Too low leads to the risk of dropping below the vapor temperature and forming condensation or sweating, but if you have a lot of heat from the web, this shouldn't be a problem until you stop the line.
tjw
Posted by Tim Walker at June 9, 2006 11:23 AM
