When it comes to servicing pumps, bearings and mechanical seals, the main goal is always to prolong the pumps’ lives as best as you can. While there are occasional unforeseen situations that can affect the lifetime of the pumps--things that are out of your control--there are some factors and key problematic areas that are important to be aware of. Unfortunately, these factors can also lead to the most probable pumping mistakes that cause pumps to be pulled from service and operation. Jim Elsey from Pump & Systems curated a list of Common Factors that Affect Pump Life, and from there we picked what we think are the top 4 frequent pumping mistakes:
Here are some recurrent mishaps to avoid and prepare for:
One of the most common pumping mistakes that causes centrifugal pumps to require service is the failing of mechanical seals. According to Elsey, bearings and seals are “early indicators of pump health and the harbingers of what is happening inside the pumping system.” The foremost way to ensure that a pump remains ‘healthy’ is to work the pump close to its BEP, or best efficiency point. Elsey states that when the pump is operating near its BEP, the pump will encounter a minimal amount of radial force--and that’s a good thing. When a pump is not operating close to its BEP, most likely the pump will experience a high amount of radial force, “causing shaft deflection and consequently injuring the bearings and mechanical seals.”
A common mistake for ball bearings is the admission of contamination. In fact, over 85 percent of ball bearing failures are from oil, dirt or foreign material contamination. Elsey even claimed that just “250 parts per million (ppm) of water will reduce bearing life by a factor of four.” This is why oil service for bearings is so vital to the health of pumps.
The characteristics of the fluid being pumped are extremely important in regards to the service. We typically look at the pH, viscosity and specific gravity of the fluid. Elsey states, in terms of pH, if the fluid is either “acidic or caustic, the pump wetted parts, like casing and impeller materials, will need to hold up in service.” Other factors of fluid properties include their size, shape and corrosive qualities.
Pipe strain can cause a variety of problems with even the healthiest and strongest working pumps. According to Elsey, “the straining of pipes is caused by misalignment of the suction and/or discharge pipe to the pump flanges.” The misalignment can subsequently cause a high radial force to the bearings. Then, in reaction to that, the force and strain can cause the bearing fit to be out of coordinance with the other bearings, making the centerlines go into separate planes.
Have you made one of these mistakes and need your pump repaired? Visit our website or call us at 724-307-3773 to learn more about our services and what we can do for you!