A large paper mill operates a 500 HP drive running a 15′ diameter steam roll at 800 RPM. Due to the layout of the process, a significant shaft offset existed necessitating the use of a universal shaft.
During operation, they noticed a vibration. Over the years, it became more and more severe. The vibration grew to the point where it shook the entire dryer platform.
We reviewed the application. One of the first things we looked at was the frequency of the vibration. It turned out to be twice the RPM. This indicated that the vibration might be initiating at the universal shaft.
The next step was to see if the shaft was properly phased – it was. We then reviewed the alignment and found compound angles. This was the source of the vibration. A Cardan design universal-joint produces an irregular velocity in its center section. If you have uneven angles, the second joint will not cancel the velocity change. The result is a vibration, which in this case resonated throughout the entire dryer.
The process didn’t allow any alignment changes. We proposed a constant velocity universal shaft. This design is more expensive than the traditional Cardan design, but allows for greater angles while maintaining speed – problem solved.
If you have a vibration problem, let us see if we can help you.