All hot oils have a limit to the time they can be utilized in an extruder. The key factor is mainly the type of fluid being used, according to Duratherm Extended Life Fluids, Lewiston, N.Y. The company offers a monthly e-newsletter that details how to get the most out of your heat transfer fluids regardless of the application.

In a recent edition, the company cautioned that process temperatures and production rates are just a few of the many factors involved in determining the length of time between fluid changes. Use of a proper heat transfer fluid intended for extrusion is always recommended for extruding applications. However, while there are many fluids available, only a few fluids the additives necessary to enhance their performance and to significantly extend the time required between oil changes in an extruder.

Duratherm recommends a fluid analysis program be utilized to track the life-cycle of the oil and determine the oil change interval best suited to your application and type of oil. Most heat transfer fluid vendors provide a no-cost or nominally charged oil analysis service.

To subscribe to the e-newsletter or for more information on the company’s heat transfer fluids for extruding applications, visit