Why do fan balancing on time, what to do before going for fan balancing and how to balance a fan? These are many questions maintenance team have. This series of articles on Fan and blowers aims to shed more light on this subject.
Fans and blowers are an integral part of many manufacturing and industrial sites. It is quite natural that the impeller gets worn (in case of material handling fans) or dust and other particles get deposited on the machine creating an unbalance force. Many production facilities wait till vibration gets very high or even critical levels before taking action.
This in turn cause invisible machine damage and adds long term maintenance costs, this post will help you take a more informed descision when it comes to your fans or blowers. Read on!
Why Fan Balancing on time?
+ Fans are often an integral part of production, any downtime costs production.
+ Vibrations higher than normal limits intiate failure of load supporting components such as bearing.
+ Unbalance acts additional load on the bearings and reduce the life.
+ Imagine a fan rated to operate at vibration levels less than 3.5 mm/s RMS, many maintenance team wait till the vibration level reaches critical levels like 9 mm/s or more till they choose to carry out balancing. The fan is forced to operate at vibration levels 4-9 mm/s till it reaches the "high" level as considered by the maintenance team. And it can take weeks to months for the vibration to increase to this level.
+ Operating Fans at this "slightly" high vibration has an immensely negative effect on the bearing life.
+ Studies show that an increase in 10% load causes the bearing life to reduce by 25% for ball bearings.
+So the slight increase in vibration, could contribute to a tremendous increase in rated vibration
For full details on paper and calulations IOSR Journal of Mechanical and Civil Engineering (IOSRJMCE) ISSN : 2278-1684 Volume 1, Issue 2 (July-Aug 2012), PP 47-54. All credits to author of the paper.
+ Delay in carrying out maintenance thus reduces the life of bearings.
So what to do when fan vibration increases?
+ The number one priority should be to do a complete vibration analysis to diagnose the problem (If available)
+ Clean the fan impeller. Any dust or material deposits should be removed.
+ Inspect the fan impeller for wear and damages. If minor wear, it can be repaired safely by welding.
+ Ensure Fan dampers, inlet / outlet is clear and free of any deposits.
+ If above actions does not decrease the vibration, call an expert for in-depth diagnosis and on-site balancing.
*Osborne Engineering provides dynamic balancing all accross the Middle East and Europe. Inlcuding UAE, Poland, Oman, Bahrain, Kuwait, Saudi Arabia, Qatar.