Why Bearing Alignment is Critical to Pump Life

Blog | June 3rd, 2019

Bearing alignment difficulties impact all shaft-driven systems to some degree. In a ventilation fan, a poorly aligned bearing will shorten the lifespan of the appliance, and then a cool room will fill up with stifling heat. Noise, screeching vibrations, all kinds of nasty headaches will crop up until the fan stops working. With pumps, though, the issues dredged up by bearing misalignment issues can be so much worse.

Analyzing Fluid Drive Deviations

It’s not possible to look through pipe walls so that we can see how a pump is performing. Instead, by applying piles of analytical data, we can conjure up a three-dimensional image of a pump’s workings. The virtual cutaway focuses on the volute section, where an impeller is being propelled by a rotor. As long as the pump bearings are aligned just-so, a small amount of clearance exists between the impeller and the internal curves of the pump volute. If, however, a bearing misalignment error occurs, the gap closes. Now there’s an angular tilt, which is throwing off the impeller edges. A wear pathway is scoured across the pump chamber’s interior geometry because of the tilt. The damage is done.

Pumps Are Misalignment Sensitive Machines

It’s true that a high-performance pump will experience a discharge drop if its bearings aren’t aligned correctly. In our previous example, the one that used a simple ventilation fan, a loss of perpendicular functionality caused wear patterns too. Only those patterns didn’t come at such a high cost. With fluid pumps, it’s an entirely different matter, for pumping applications rely heavily on rock-solid seals. Head capacities, discharge rates, flow velocities, all of these fluid performance factors experience significant hits when an impeller suffers a trajectory-skewing blow. To prevent pump bearing misalignment errors from causing performance-attenuating impeller problems, engage the services of an expert pump installer. Even then, with the installation work done, keep a wary eye on the equipment. Pump bearings need to stay properly aligned if a fluid system is to operate efficiently.

For that latter job, system managers turn yet again to a predictive planned maintenance program. The techs assigned to this job check for thermal losses and low bearing lubrication as a matter of course. They listen for signs of bearing misalignment noise and impeller damage. All the same, it’s hard to peer deep down inside the dual races and rolling elements. Running a degree or two out of true, asymmetrical stresses cause long indents and intermittent galling depressions to strike what should be a smooth-running pump mount. Discharge inefficiency is the immediate upshot here, but it’s an effect that’s slowly overtaken, with equipment wear acting as the eventual equipment destroying winner.

Mobile Hydraulic Specialties Pty Ltd

Factory 89, 38-40 Popes Road
Keysborough, Victoria, 3173

Phone: (03) 9798-6511

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