Alignment of centrifugal is quite important that we can illustrate with this real-life case. Once in certain waste water treatment plant, an operator faced problem with the pump at the Crane Engineering department and informed the problem. He had to replace bearings of the centrifugal pump at certain station too often and therefore wanted the Engineer to have a look at it.
As the account manager of the operator visited the location personally, it was quite obvious that something was definitely wrong. The manager came there because before seeing the pump, as he was able to hear big sound of grinding of the bearings even from outside of the lift station.
After checking, it was discovered that there was misalignment between pump and the motor. This was not only wearing out the bearing prematurely but also causing very loud noise too.
Almost 50% of damage that happens in rotating machinery is just because of misalignment. Bearing damage, machine vibration, premature seal wear, as well as various coupling damage are the cases of certain issues that sanitary Valves often experience, if they are improperly aligned during installation. Any misaligned pumps may also draw about 15% more power than any aligned pumps.
Three common methods and tools available that is used for aligning pumps. Let us see various pros and cons about each of them:
- Straight-edge -This method needs placing any straight-edge on the motor and pump coupling, then making any visual check for seeing if all the components are properly aligned.
- Pros
Much quicker and easier to perform
- Cons
It is highly inaccurate. Modern high-performance machinery and outlooks for up-time need more accurate dimension.
- Reverse dial indicator
This method uses 2 indicators which check for angularity and radial run-out. All the readings are put for proper alignment in the mathematical formulas for calculating shim needs.
- Pros
Very accurate, much more accurate as compared to above method.
- Cons
- Cumbersome and time consuming
- Reading errors
- Needs a high technical skill
- Laser alignment
In this method, laser is used for determining the relative position of shaft. The computer will then make recommendations for adjustments procedure.
- Pros
- This is the most accurate method that is available
- Once operator gets familiar with it, then he can align pump/motor fast.
- Cons
- Cost – It is one of the most expensive methods available
- At the beginning, it is much more complicated to do set up
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