Understanding and Addressing Varnish in Paper Machine Systems, 2008 PAPERCON Conference

ARE YOU A TAPPI MEMBER? TAPPI members have exclusive, FREE access to technical conference papers and presentations six months after the conference in TAPPI's e-library. The e-Library offers:

• Unlimited access to more than 18,000+ documents
• Fast, robust search engine for fast search results
• Members get FREE access to conference proceedings, TAPPI JOURNAL articles, Paper360º articles, archived Solutions! articles, and much more
• View thousands of technical paper abstracts
• Ability to search by keyword, title, author, events or industry segment

*Technical papers and presentations are available for sale immediately following the conferences before the 6 month embargo period.

Please Note: This document will be available in PDF format in the "My Electronic Documents" link on the home page once your order has been completed. Please make sure you have the latest version of Acrobat Reader. Click on the Acrobat Reader icon to check for the latest version, it’s FREE. To print a hardcopy of a PDF file correctly you must have a postscript printer. If you are not sure if your printer is a postscript printer please refer to your owner’s manual.

Free radicals formed by thermal and oxidative stresses are frequently the root cause for varnish and deposit formation in controlled crown rolls, winders, ENP’s and any other servo controlled hydraulic systems. Traditional methods of analyzing used oils, such as viscosity measurement, acidity or carbonyl oxidation, were originally developed for hydraulic oils based on Group I base oils and are usually inadequate to predict eminent field problems using Group II, III and IV base stocks. A more suitable method for monitoring paper machine oil acceptability in the field, particularly for the newer Group II and higher base stocks, is to measure depletion of the various antioxidant types present in the system. Also critical is the availability of new tests that allow varnish problems to be identified. This paper examines paper machine oil varnish from a well-rounded perspective to allow plants to predict the onset of this problem and take proactive steps to mitigate varnish.