Vibration (shaking) of vacuum rake dryer
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At present, one of the vacuum rake dryers in our factory (12,000 L capacity) experiences significant vibration during operation, with strong shaking felt in the foundation and the floor. Some time ago, the internal hollow shaft had many cracks; we believe this was caused by a loss of dynamic balance, as there was no issue with the material itself. A new shaft was installed, and it operated very smoothly after that. However, once hot water was passed through the shaft, the vibration became extremely severe. We initially suspect that it is the hollow shaft – the liquid level can only reach a little over half of its capacity, which leads to a loss of dynamic balance and thus excessive vibration. Could anyone please help us find a solution? An illustration of the equipment is attached
Couch raiding time – let’s see if it can be restored
I guess the new shaft wall being replaced is quite thin! After the heating medium is filled, thermal stress causes deformation, resulting in the two ends of the shaft no longer being aligned; this leads to eccentric resonance when the mixer starts rotating! My humble opinion!
The operating speed is 30 r/min. The concentricity has been checked and there are no issues. We still believe that the problem is caused by water not being able to fill the shaft properly, which leads to water sloshing around; we just can’t think of a good solution
This post was last edited by jinqhuaxz on 2019-3-19 at 12:17. When the hollow shaft is heated, its weight increases, its deflection increases, its frequency changes, and the amplitude of vibration also increases. The wall thickness and material grade of the hollow shaft should be increased. Additionally, experts can be hired to conduct vibration analysis simulations to show the changes before and after heating the water. We have legitimate vibration analysis modules that we can use to give it a try; it’s a good opportunity for learning and communication*. Haha. The original hollow shaft broke; it is likely that there were issues with its strength, and it seems that no thorough analysis was conducted during the design phase.
I’m not sure what material is evaporating at your company; we use steam as the heat source, and we have never encountered such a situation. It is very likely that the wall thickness of the shaft is too thin, caused by welding factors as well as deformation after heating with hot water.