Tip's & How-Tos
Understanding Heat Transfer Fluids and Your Extruder
All hot oils (heat transfer fluids) have a limit to the time they can be utilized in an extruder. The key factor affecting service life is mainly the type of fluid being used. However, process temperatures and production rates are just a few of the more minor factors involved in determining the length of time between fluid changes.
Understanding Fluid Degradation
The scientific definition of oxidative degradation is the reaction of oxygen (in air) with the fluid by a free radical mechanism to form larger molecules which end up as polymers or solids. These thicken the fluid thereby increasing its viscosity.
Custom Fluids: When Off-The-Shelf Won’t Do
Having a hard time finding the right thermal fluid for your application? Having an even harder time finding a company willing to listen and invest the time to help?
Understanding Heat Transfer Fluids and Your Extruder
All hot oils (heat transfer fluids) have a limit to the time they can be utilized in an extruder. The key factor affecting service life is mainly the type of fluid being used. However, process temperatures and production rates are just a few of the more minor factors involved in determining the length of time between fluid changes.
Start-Up and Shut-Down Procedures
Regardless of system design, size or heat source, there are a few basic procedures that should be followed when starting up or shutting down your heat transfer system. Following these procedures will help maximize the life of your fluid by reducing incidents of thermal degradation.
Avoiding Oxidation and Thermal Degradation
Oxidation occurs when a fluid comes in contact with air at elevated temperatures and is one of the most common ways a fluid suffers from degradation, usually resulting in sludge formation within the system. While the various heat transfer fluid chemistries are affected at different temperatures, the most common petroleum-based fluids will experience oxidation at temperatures above 200°F. In fact, it's generally accepted that for every 15 degree increase in temperature (above 200°F), the rate of oxidation doubles.
The Lowdown on Open Baths and Heat Transfer Fluids
Nothing puts a heat transfer fluid to the test more than an open bath application. By nature, these applications leave the fluid exposed to the atmosphere, resulting in the number one cause of fluid breakdown: oxidation.
Guide to Fluid Selection for Systems Under 250 Gallons and/or Electrically Heated
For systems with a capacity under a few hundred gallons, it is typical to find they are open-to-atmosphere, in that there is no inert buffer (nitrogen blanket) between the fluid and the atmosphere (usually at the reservoir or expansion tank). These types of systems have unique considerations for fluid selection.
Fluid Selection for Systems Over 250 Gallons
The intent of this paper is to help you make an educated decision when selecting a heat transfer fluid. While most applications are unique, this guide should provide enough background to make choosing a fluid for your application much easier.
Understanding Flash, Fire and Autoignition Points
Heat transfer fluids are exceptionally safe if specified correctly for the application and some basic guidelines are followed with respect to their use and handling.
