Overhung Blowers/Fans

[Hatch]

In my experience, overhung blowers are a maintenance nightmare. When new, they seem to run within specs, but as they get older, high vibration problems seem to ocurr overnight and the fix is not always obvious.

Without showing any more of my bias, I am wondering what others have found with this design of blower/fan? Would you recommend the use of this type of fan? What maximum HP do you think would be the practical limit for it? What are the advantages/disadvantages?

Thanks in advance for your comments.

 

[Consultant]

Understanding Gyroscopics effect on Overhang rotor will give solution.

 

[ArneLindholm]

The statement that overhung ventilators in specific are more prone to problems than any other fan designs of course reflects that you have been subject to bad designs. Each time you are flying a jetliner today, you are subject to a transport hardly being possible without an overhung rotor. The hot end turbine of almost every jet engine has an overhung fan rotor of some kind. There are, apart from basic flow dynamics, a small number of vibration basics to care for when designing an overhung. I have a fair experience from this and I must say that the chance is great that if you attack your problem machinery with a reasonable effort, costing much less than any repair, you have an almost guarantee that you will succeed in modifying them to flawless operation. You need any make of vibration collector and a little bit of e-mail correspondence with me or anyone working in the field. You are welcome anytime, there are no strings attached from my side. Happy New Year/Arne