Dryers 201: Grades of Drying Systems  

Agricultural Grade
This Drying System is designed to be used on a seasonal basis, generally operating about 1,000 to 3,000-hours/year.  An otherwise properly operated and maintained agricultural grade dryer drum operated 8,400-hour/year will develop fatigue cracks in its structure within the first 1 to 3-years of its lifespan.  As fatigue cracking progresses, the drum will catastrophically fail if it is not repaired.

Light Industrial Grade
This Drying System is designed to be used 3,000 to 5,000-hours/year.  An otherwise properly operated and maintained light industrial grade dryer drum operated 8,400-hour/year will develop fatigue cracks in its structure within the first 3 to 6-years of its lifespan.  As fatigue cracking progresses, the drum will catastrophically fail if it is not repaired.

Heavy Industrial Grade
This Drying System is designed to run at capacity in excess of 8,400-hours/year.  TDC’s defines heavy industrial design as having no stresses in the fabricated parts that are known to exceed the cyclic endurance limits or the static yield strength of the materials of fabrication during normal operation.  A properly operated and maintained heavy industrial dryer drum will not have fatigue cracks in the structure after 10 years of operation.

Utility Grade
The increasing popularity of Bio-mass as a fuel for industry has lead to the development of the Utility Grade Drying System.  The greatest difference between a heavy industrial and a utility grade drying system is that two drying systems are used where normally one would be sufficient.  The reason being that the fuel the system is supplying to create power has to be met on a continual basis.  Another difference is that the system is designed to make it as easy as possible to make repairs and replace damaged or worn parts.