Any industrial rotary kiln is going to have to deal with immense heat, pressure, and weight – meaning there will be a need for a lot of maintenance and upkeep. In many cases, keeping a good stock of kiln spares on-hand can help keep your kiln running, but some damage cannot be fixed with a simple part swap.
Possibly the biggest danger to a kiln is becoming warped. A kiln that is even slightly warped will be compromised. It won’t heat materials evenly, and it will probably cause significant vibration and strain on all of the rotational mechanisms. Left uncorrected, this could potentially end up damaging the entire system.
So, let’s talk briefly about how kilns become warped, how to prevent it, and what few options you have if warping does occur.
How Do Kilns Become Warped?
The most common reason a kiln would be warped is if it ceased to rotate while hot materials were still inside. While it was built to withstand high heat, it was designed assuming that heat would be evenly spread over the entire interior. If the kiln stops, and all the heat concentrates on a single part of the interior, warping and other damage may quickly follow.
For this reason, it is imperative that a kiln never be allowed to stop more than briefly when hot. You should have at least one auxiliary drive and one or more backup power sources so that nothing but absolute catastrophe could allow the kiln to stop rotating.
Allowing the kiln to ever run without these failsafe steps in place is running a major risk.
The other most common cause of warping is when the refractory layer becomes compromised. If the inner layer is damaged, that allows heat to easily escape to the outer shell, damaging it. This can happen in a few different ways.
The refractory layer comes loose.
The inner layer relies on anchors which may degrade over time, potentially even coming loose and allowing the inner layer to crack.
Too many rapid temperature changes.
Refractory layers can tolerate temperature changes, but they must be done relatively slowly. Repeated rapid changes in temperature can crack the layer.
Too much moisture in the kiln.
Water vapor and other vapors inside the kiln can potentially damage the refractory lining, cracking it or encouraging it to come loose.
Any other abnormal operation.
Generally speaking, the refractory layer is one of the most easily-damaged parts of a kiln, and can be harmed by most abnormal operations.
What Can Be Done About A Warped Kiln?
Warped kilns are extremely difficult to repair, and in many cases, will have to be replaced – at enormous cost, of course. However, there are two measures which may sometimes work:
In some cases, applying high heat to the opposite side from the warping will undo the damage, and draw it back into line.
It may also be possible to cut out a portion of the shell, then re-align the riding rings and carrying rollers to adapt to the warp, then weld the shell back together. This will look ugly but may still work.
Otherwise, though, if your kiln has become warped, you need to call in the experts at Kiln Technology Company.
Kiln Technology Company Can Help
Kiln Technology Company has plenty of kiln spares and extensive experience in repairs. Call us today!