A couple of weeks back, we published an article discussing the top vibration problems in pumps and how to rectify them. Continuing with our discussion, in this post, we will focus on a specific vibration problem – misalignment of the pump shaft.
The life of a pump depends on how well it is maintained. Misalignment of the pump shaft is one of the top reasons for pump failure. Even a small misalignment – just a fraction of an inch – can drastically decrease the pump's lifespan.
What is the misalignment of the pump shaft?
Shaft misalignment occurs when the shaft or surface is dislocated from its ideal position.
Misalignment is the deviation in the shaft position when the pump is operating at standard conditions.
Misalignment can lead to troubles in either a section of the pump or its entirety. Misalignment is a problem even for pumps with flexible couplings. Though a flexible coupling has more room for movement than a standard coupling, it can only function with small misalignment.
Effects of Misalignment of the Pump Shaft
Misalignment in pumps can lead to several troubles like:
- Seal failure
- Bearing failure
- Increase in energy consumption
- Excessive heat generation
- Increased vibration
Hence, you must detect the signs of misalignment as soon as it occurs to prevent the catastrophic failure of the pump.
Watch Out for these 5 Common Signs of Misalignment of the Pump Shaft
You can spot misalignment if you notice the following signs:
- Frequent wear or failure of machine components like coupling, bearings, and belts, and mechanical seals. The wearing down of grooves and discoloration indicate possible misalignment of the shaft.
- Shifting or strain of attached piping and base plates. This creates excessive stress on critical components like seals, bearings, and couplings.
- Loose bolts and nuts at the base where the pump is attached to the foundation.
- Increased power consumption.
- Excessive noise and vibration during pump operation.
*Note that some amount of vibration is standard in all pumps. Even if the pump's shaft is aligned correctly, it does not guarantee the absence of vibrations. If you aren't sure if the pump is vibrating normally or experiencing excessive vibration, we recommend calling professional pump technicians to help you sort the issue.
How to rectify the misalignment of the pump shaft?
It’s not practically possible for pumps to operate with zero misalignments of the pump shaft. There is bound to be some amount of misalignment. It becomes an issue, only when the misalignment is more.
The general rule of thumb is that misalignment within 0.002 inches does not cause any trouble. However, we recommend that you don't strictly adhere to this number, as the actual number varies depending on the type of pump shaft, configuration type, and other factors.
Refer to your pump’s manual or contact your pump manufacturer to find the optimal number for your specific model.
A common way to rectify pump misalignment is by using a close coupling. In close coupling, the pump and motor are joined directly by mounting the motor onto the pump. When done correctly, close coupling offers a precise alignment and secure hold. Close coupling is a cost-effective solution to rectify the misalignment of the pump shaft.
Besides close coupling, other ways to rectify this problem are – flexible couplings, laser shaft alignment, and fixed coupling.
Don’t Let Misalignment Affect your Pump’s Lifespan
Industrial pumps are generally robust and sturdy. They are designed to last for years to come. However, if not maintained properly, you run the risk of frequent downtimes, expensive repairs, and even total failure.
Misalignment of the pump shaft is a significant issue, and if left unchecked, it not only reduces the optimal functioning of the pump but can even lead to substantial hardware damage. To avoid these issues, watch out for the five signs of misalignment mentioned in this guide.
If you notice any of these signs, we highly encourage you to call in qualified pump technicians to resolve the issue as early as possible. For further tips on how to run industrial pumps optimally, reach out to our pump experts at Sintech, India’s leading industrial pump manufacturer and exporter.