Equipment misalignment is one of the most critical concerns of every pump operator. When any rotating shaft within any piece of equipment (pump, motor, gearbox, cooling fans, etc.) gets out of alignment, bad things are bound to happen. Parts can experience excessive wear and tear. Machinery can become damaged. The life span of equipment will be shortened. Downtime and repairs could be very costly.
What is Misalignment?
Misalignment happens when two rotating shafts are not in precise alignment with one another. The shafts could simply be offset or there could be an angular gap at the coupling. Even the slightest amount of misalignment can cause major problems. Machinery misalignment is a common issue in pump systems and is one of the biggest causes of equipment failure.
Alignment at Installation and During Ongoing Maintenance
The most frustrating aspect of misalignment is that you may not always know it is happening until the damage occurs. Precision alignment is crucial when installing a pump system. The foundation, base plate, drive shafts, impellers and every component must be in perfect alignment to get the best performance, efficiency and lifespan from the machinery.
Precision alignment during installation is necessary. However, it is only the beginning. Alignment should be checked and adjusted/corrected regularly. Shafts can easily slip out of perfect alignment during standard operation or as other adjustments are made to the system. This is true whether you have steady flow rates, speeds, temperatures and pressures or not. You need to carefully monitor the alignment of all rotating shafts and make adjustments to ensure optimized results.
Pump Misalignment Categories
Machinery experts divide misalignment problems into four categories:
- Vertical offset alignment (center lines of shafts are offset vertically)
- Horizontal offset alignment (center lines of shafts are offset horizontally)
- Vertical angle misalignment (angular misalignment of two shafts in the vertical plane)
- Horizontal angle misalignment (angular misalignment of two shafts in the horizontal plane)
Common Sources of Pump Misalignment
Here are some of the causes of misalignment that we see commonly at DXP Pacific:
• Base plate settling (can also cause “soft foot”)
• Deformation of shaft (usually caused by startup torsion)
• Human error during installation or realignment maintenance
• Pipe strain
• Thermal expansion
• General wear and tear of components over time
Misalignment Detection Techniques
Beyond just alignment checks that should be part of your ongoing preventative maintenance program, there are other ways you can tell that your pump alignment may be off. It takes a trained pump expert to identify some specific alignment issues. However, there may be signs that operators can look for to identify misalignment in any piece of pump system equipment. Here are some of the best techniques you can use to uncover these symptoms of misalignment.
Vibration Analysis—Excessive vibration can happen for a number of reasons, including misalignment. You can utilize accelerometers, proximity sensors or velocity transducers to monitor vibration and pinpoint the problem(s).
Thermography—Misalignment can often cause abnormal hot spots in certain areas of equipment during operation. Friction increases when shafts aren’t aligned properly and temperatures go up. Thermal imaging can be used to find these hot spots and potentially identify misalignments.
Oil Analysis—You can physically inspect the oil. Any discoloration, metal particles or abnormalities in the fluid could the be the sign of misalignment or other internal problems.
Laser Shaft Alignment—Technology is very advanced, especially with today’s laser shaft alignment systems. In the right hands, they can be a useful tool to obtain a precision alignment. However, like with any tool if used improperly, it can have catastrophic results. When used properly, during installation and during preventive maintenance checks, lasers can be an effective in prolonging the life of rotating equipment. Lasers can make a significant difference, though it does still help to know some old-fashioned manual alignment techniques, like dial gauges, for an added level of accuracy.
DXP Pacific can help with all pump system alignment needs, from accurate configurations and installations to ongoing maintenance and repairs. We can also provide professional equipment alignment training services for your staff, and we have a number of instructional videos on our website relating to alignment. We understand how costly misalignment and downtime can be and we take the necessary steps to ensure optimized pump performance. Contact us today to learn more about our services.