Our work / Mechanical design
Continuous coating drum for biocarbon pellets
A 15-foot rotating drum that coats biocarbon pellets as they pass through, designed in 3D and checked with finite element analysis before any steel was ordered.
The plant needed a coating drum that runs around the clock. Pellets enter one end, tumble through a spray of coating as the drum turns, and leave the other end coated.
Design
We worked from the plant's specification and the drawings and photos of an existing coating drum.
- The drum is 53 inches in diameter and 15 feet long, built from a 10-foot and a 5-foot shell section.
- Eight full-length paddles lift the pellets and drop them through the spray.
- The drum rides on two roller rings supported by four wheels. Two thrust wheels hold it in place along its length.
- A base-mounted AC motor turns the drum through a 17-tooth pinion, a #100 chain and a 192-tooth sprocket around the shell. A VFD sets the drum speed.
- The frame is 6 x 4 tube and 6 x 6 angle, with a discharge chute at the outlet end.
Analysis
We ran a finite element analysis of the drum shell with the paddles loaded and checked how far the shell deflects before the design was released.
