Spiraling
Twisting of brick rings out of radial alignment inside a rotary kiln when the lining works loose.
Kiln crew term for the circumferential creep of loose brick rings relative to the shell, so the joints that were laid straight along the kiln axis start to wind around it like a screw thread. It comes from rings that were not keyed tight, shell ovality and tire creep, and it ends with bricks dropping out of the crown. Tight keying, steel shims and controlling ovality prevent it.
Inlet rings are spiraling, the joints have walked a full brick width around the shell since startup.
Also heard as
- brick spiraling
- twisting
- ring rotation
Related terms
Key
The last brick driven into an arch or ring to lock it tight, or a shape that tapers in width for turning circles.
Ovality
Out-of-round flexing of a rotary kiln shell under its tires, which crushes and loosens the brick lining.
Pogo stick
Telescoping prop used to hold bricks against the upper shell of a rotary kiln until the ring is keyed.
Ring
Circular buildup of material inside a rotary kiln that dams the flow, or one circular course of lining brick.