The deformation of a rotary kiln shell from a true circle as it rotates under its own weight on the tire supports, measured with a shell ovality gauge. Excessive ovality, usually from worn tire pads or too much gap between tire and shell, works the brick lining every revolution, crushing hot-face edges and loosening rings. Kilns with high ovality show short brick life under the tires.
Ovality under tire 2 is way over limit, no wonder the brick keeps failing there, shim the pads at the stop.
Measure ovality with the kiln running hot. The number that matters is the one under load at temperature.
Also heard as
- shell ovality
- relative ovality
Related terms
Spiraling
Twisting of brick rings out of radial alignment inside a rotary kiln when the lining works loose.
Ring
Circular buildup of material inside a rotary kiln that dams the flow, or one circular course of lining brick.
Spalling
Cracking off of pieces or layers from the hot face of a refractory lining.
Key
The last brick driven into an arch or ring to lock it tight, or a shape that tapers in width for turning circles.