To download the below  and all other Useful Books and calculations Excel sheets please click here 

To download the below  and all other Useful Books and calculations Excel sheets please click here 

Kiln Gear and Pinion Alignment

Our most recent inquiry from Alan in the Asia-Pacific region:

We are commisioning a 67.4m kiln with a double drive, the west side motor has the inching drive. The kiln turns clock wise from the burner end. The pinions are new but the girth gear is refurbished with two or three hand ground areas. The construction team have set the back lash and root clearance correctly on the good section of the gear. When running cold and empty, there is a rumbling noise and vibration where the hand ground area come in contact with the west side pinion. On opening the cover in this area it is found there is no back lash clearance for this area of the hand ground portion of the gear.

The construction team say when the kiln starts to run in the hot state the kiln will lift and achieve the desired clearance.

Is this correct?

If not what would be the effect on running a kiln in this condition?

at the tightest spot to the minimum or even a little extra as specified by the gear design. If the root clearance is as much as doubled (at the tightest point) the gear capacity is only derated by about Chances are the assumption may not be entirely correct. Whether or not the root clearance increases when the shell comes up to temperature depends on the relative expansion between the tire and the gear. Certainly as the tire expands the root clearance will increase. But the gear also expands, which reduces the root clearance. If the tire expands more than the gear then there will be increased root clearance (back lash), conversely if the gear expands more than the gear that would decrease the root clearance. Since the root clearance in the cold condition is already too tight why take any risk? Re-adjust the rollers now to set the required back-lash and root clearance

15%. Conversely if the backlash is zero (the root clearance is too tight) there would be tooth tip interference, which can overload a tooth as much as 200% and cause tooth breakage.

Posted by Walter Gebhart