Blown film
Vol. 26 #3, December 1999
Centrifugal Fans - (used for cooling in blown film, trim reclaim, material conveying, etc.) What to do when they suddenly malfunction. Begin your investigation with a search for what has changed.
Was a new motor installed?
1) It may have been wired (3 phase) so that it runs backwards. It will still develop pressure and volume - just not as much. Check the fan rotation!
2) Is it a belt drive system? Did the sheaves get reversed? Is the fan running the speed it should be?
3) Did someone substitute a 3550-rpm motor for a 1750 - or vice versa?
4) Does it have in-line air filtration? Check and see if they are dirty or wet.
5) Has the supply or discharge ducting been changed? Is it longer/shorter? Is it bigger/smaller in diameter?
Attached Equipment Changes
1) Has the equipment its working with changed? Is it now required to do more/less work than before?
Systematic, step-by-step detective work may identify a change.
- Dan Cykana, Bemis Mfg. Co.
See also
Blown film air cooling
Blown film cooling - air parameters
Blown film versus the cast film process
Centrifugal fans
The effects of molecular structure, rheology, and orientation on polyethylene blown film