We often act as representatives going to rebuild shops to ensure our customer receives a quality build they deserve and to ensure the shops have the capabilities they sell. As well, we also oversee equipment installations and commissioning. One particular plant site went thru 8 blowers in 15 months and nobody could figure out why this was happening. When API went to site they pulled the equipment and did a failure analysis in the field finding the previous rebuild shop was using worn out parts and band aid fixes to get the equipment out the door. API worked with our client and a local rebuild shop to come up with a lasting fix as we didn’t have the time to wait on new parts. We found that the shaft splines and the timing hub splines had been fretting due to the severity of the service loading up for 1 minute every 30 seconds. This caused a ratcheting effect on the shaft and hub splines causing the blowers to lose time and rub rotors further causing bearing failure or worse a split casing.
When we had the blower in the shop we decided to key the timing hubs to the shafts with a round key. The round key was used to prevent crack propagation from the sharp edge formed with a square key. When the blower was removed we had also inspected the condition of the base and it was found to be delaminating from the grout causing an out of phase vibration. This was caused due to the base no longer being sealed and water leaking in under the base frost heaving it from the grout. API had to jack hammer the existing grout out from around the base and cut off the existing sole plates as they were far from level or on the same plane as each other. API had new sole plates built and installed then proceeded to reseal and grout the base to prevent any water from seeping under and frost heaving the base from the grout. Once started the blower has ran without any issues.