July 6, 2016
Environmental Impact on Precision Shaft Alignment
By James Pekarek
We work with clients in many types of harsh climates, from cold with rain, sleet, snow & ice to hot humid and hot & dry and everything in between. Whatever the climate, the need for equipment maintenance intensifies with the severity of the climate. Harsh climate conditions will create situations where precision shaft alignment of pumps and outdoor equipment may be difficult or near impossible. Increased attention to maintenance will minimize the negative effects of climate on rotating equipment.
In the late summer months last year, I performed shaft alignment training at a facility in a desert environment in the Southwest U.S. During their winter months the climate can be well below freezing and during summer, temps can be 115+ degrees. These extremes in temperatures will cause damage to the rotating machinery as well as the concrete and grout mounting platforms and steel machine skids if precautions are not taken, such as:
- More frequent PM checks.
- Additional lubrication frequency.
- Applying protective coating to exposed concrete and hardware.
- Taking steps to prevent the infiltration of moisture.
During rainy seasons, moisture will get into cracks and pores in the concrete, then freeze cracking the foundations and mounting platforms. This is a significant issue for areas in the northern part of the country. Foundation cracking/settling is a major cause of previously aligned machines “mysteriously” becoming misaligned. Rust and corrosion build up also contributes to this and makes realignment difficult if not cleaned off.
In the Southwest desert areas, the extreme fluctuations in temperature and dryness also cause foundation problems but can cause another unforeseen issue, such as thermal growth problems simply from the changes in ambient air temperature from night to day. During winter the alignment at ambient will often be different than during extremely hot weather due to huge temperature differences. Many parts of the country experience temp swings of 80 to 100+ degrees F from winter to summer. This can cause significant changes to the growth rate of metals. Many outdoor facilities will have their technicians align the critical pump systems twice per year. Once in the cold winter and again in the hot summer.
In coastal areas the constant humidity combined with salty air causes severe rust and corrosion to mounting hardware, couplings and piping. Damage from rust corrosion can be a severe factor for facilities and maintenance teams to deal with.
The above and below pictures are of a pump skid experiencing all of these environmental related issues. The foundation was severely fractured from water infiltrating cracks in the concrete foundation then freezing. The shims and mounting hardware were rusted and corroded and the huge temperature swings were causing misalignment from summer to winter.
In one picture you can see that the thermal growth had caused a “bolt bound” situation to where the motor feet bolt holes were slotted so much that the mechanics had to stack washers under the bolt head to provide a enough surface in which to clamp down on. (This is not recommended, however it was what they had to work with at the time until more extensive corrections can be made.)
Damage like this can be minimized with protective coatings applied to the hardware, concrete bases and shims, thermal blankets applied to the pipes and protecting against water, frequent maintenance, cleaning and alignment checks.