The heart of almost every Ronning Dryer system, Direct-Fired or Indirect-Fired, is the Ronning Three-Stage Dryer Drum, which provides higher capacity with lower inlet temperatures and higher residence time. 

Within the Ronning Single-pass Three-Stage Dryer Drum, ingredients travel through three distinct zones of flighting, material flow and temperature. The three stages maximize heat transfer rates and lengthen product retention time. Low average temperature and limited exposure to hot metal surfaces protects nutrient value and digestible amino acids in feed ingredients.

The Ronning Three-Stage Dryer Drum handles larger production capacity, up to 130% more than triple-pass or steam tube dryers of similar size, meeting a wide range of evaporation requirements up to 90,000 lb/hr in a single unit.

Ronning engineers have extensive experience retrofitting our patented flighting patterns and process technology into existing rotary dryer systems to improve operational efficiencies without major equipment configuration changes.

The first stage provides several intermittent periods of short-duration contact between the product and the inlet gas; each period of contact heating is followed by a longer period of cooling. In the first stage there is minimum contact between the product and heated metal surfaces; therefore, singeing of the product is avoided.

The second stage provides long-duration contact between the product and the gas, which has been reduced to an intermediate temperature.

The third stage, or Curing Chamber, provides slow drying of larger particles at the lowest temperatures.