The ID of the tire is larger than the OD of the kiln shell to account for thermal expansion. Creep translates to the diameter clearance (diametral) between shell and tire and is calculated by creep divided by 3.14.
- Not enough creep - there is no room for kiln shell to expand inside tire, the kiln shell will become coke bottled and permanently deform. Deformed shell leads to refractory brick damage and loss along with a deformed kiln shell.
- Too much creep – wear rate of components and ovality increase due to shell sag.
- Mark the leading edge of a support pad, stop block, or fixed segment ring and run the mark up the side of the tire face.
- Allow the kiln to make a full revolution and measure the gap between the marks. Allow the kiln to make 3 – 5 revolutions, continue to measure the distance between the marks, and take the average (distance between marks/number of revolutions).
- 1/4” – 1/2" creep per revolution is preferred.
- Worn filler bars or support pads will allow the tire and shell to flex more and creep may become excessive.
- 1” of creep or more per revolution typically requires shims be added under the filler bars to tighten or round out the tire. Excessive filler bar wear under the ID of the tire may require the filler bar system to be replaced.
- Measure the shell temperature uphill and downhill of the tire and measure the tire side face temperature. Using an average for 1 rotation is acceptable.
- Without shell temperature information the creep measurement means little to understand how creep is affected by changing kiln conditions (process, climatic, etc.)
Need additional assistance? Our experts are here to help. Call 1(800) 331-5456 or visit our Rotary Kiln Helpline
