Flights, or material lifters, are critical to process efficiency in rotary dryers, coolers, kilns, and coating drums, among others. Depending on the type of rotary equipment, flights may be designed to serve different purposes:
Lifting Flights (aka., Lifters)
In rotary dryers and coolers, lifting flights help to maximize heat transfer between the process gas or chilled air and the material being processed. Lifting flights pick up the material and carry it over as the drum rotates, dropping it through the processing medium.
This cascading action creates a “curtain” of material, which increases the surface area exposed to the process gas or chilled air, promoting optimal heat transfer efficiency.
Tumbling Flights (aka., Bed Disturbers)
In other settings, tumbling flights ensure the material bed is evenly rotated and sufficiently agitated. This is useful when:
- A liquid additive (such as a coating or anti-caking agent) needs to be incorporated into the product. In this case, bed rotation helps to uniformly distribute the additive throughout the material bed as it tumbles.
- In indirect drying, cooling, or high-temperature treatment (ex., calcination) applications; tumbling flights rotate the bed for more uniform exposure of the material to the drum shell, promoting even heat transfer.
Advancing Flights (aka., Spiral Flights)
In all types of rotary equipment, advancing flights are often incorporated into the inlet end to move material away from the feed zone. This helps to put material into the processing zone faster, while also preventing backspill at the inlet.
Both flight design and pattern can have a significant impact on product quality and process efficiency and as such, are best designed around the unique characteristics of the material to be processed.
As the industry’s top supplier of custom rotary equipment, FEECO offers a variety of flight designs and customizations for lifting, tumbling, and advancing flights. In addition to custom designs, this includes standard lifting flight designs such as:
- Single bend
- Double bend
Depending on the material parameters, flight pattern may be staggered or in-line.
Attachment to the Drum Shell
Flights are typically welded to the interior of the drum shell. Bolted-in designs allow for easy replacement in cases where flights may wear out prematurely due to abrasive or corrosive materials.
Materials of Construction
Flights can be manufactured from a variety of different materials, including:
- Carbon steel
- Stainless steel
- Specialty alloys
INDICATIONS THAT FLIGHTS MAY NEED REPLACEMENT
The replacement of worn or missing flights can significantly improve the efficiency and performance of the unit, lowering fuel costs and producing product with the desired specifications.
Flights typically have a lifespan of 5 to 10 years, though this depends largely on the material being processed, with corrosive or abrasive materials causing faster wear. Flights exhibiting signs of wear such as abrasion or corrosion, or that are missing altogether, should be replaced as soon as possible.
Because flights can be incredibly custom, FEECO offers a unique simulator to test various flight designs and patterns.
The 45” diameter x 24” deep rotating drum features easily interchanged flights, a variable speed drive for adjusting rotational speed, and a clear plastic cover for visual observation.
IN NEED OF REPLACEMENT FLIGHTS?
Contact our Customer Service Team for a quote on replacement flights or other rotary drum parts. We typically require the following information:
- Drum size (length, diameter)
- Material of construction
- Number of rows of flights
- Flight specs (if available)
- Material being processed
- Preferred mounting method (weld-in or bolt-in with brackets)