Maintenance and repair functions constitute a significant component of pumping system life cycle costs, especially in terms of energy consumption. The proper selection and lubrication of bearings can help bring economies and efficiencies into line.
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Rolling bearings play vital roles as the hearts of rotating machinery (pumps included) by supporting shafts, locating loads, enabling rotation and reducing friction. When bearings need to be replaced, improper dismounting and mounting techniques can shorten their life expectancy.
In this age of environmental consciousness, OEMs around the world are competing to build better, safer and greener machines. In striving toward such lofty goals, many industries are rediscovering a fundamental principle-magnetics.
Rolling element bearings are mechanically complex compared to plain bearings, but are indispensable in a large variety of functions.
The initial cost of a pump is a small component of the pump's total life cycle cost. Progressive, proactive maintenance practices are vital to maximize pump life, minimize downtime and avoid costly repairs and lost production.
When evaluating bearing distress, the babbitted shoe surface is commonly the only area that is examined. Although a great deal of information can be extracted from the babbitt appearance, additional information exists elsewhere.
Currents are induced on the motor shafts when AC motors are employed with VFDs to drive air pumps, chillwater pumps and compressors in HVAC/R systems. Without a grounding device, these currents typically discharge through the motor bearings, causing frosting, pitting, fusion craters, and fluting.
In December 2008, we discussed some reasons ball bearings run hot. In December 2006 (ref. [1]), we described the common pitfalls of incorrectly dimensioning shafts during repairs. This time, we will examine the cousin of a ball bearing-a roller bearing-and some of the pitfalls that occasionally cause hot operation.
How to determine the root cause of bearing failure by analyzing telltale signs.
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When a component of a large circulating water pump fails in a power plant, the power plant must often spend hundreds of thousands of dollars to remove the pump from service, replace the failed component, rebuild the pump and return it to service. In addition, circulating water pumps can require work on a massive scale-they can measure 30 ft or more in length and pump an average of 165,000 gpm. Rotating shafts for these pumps can measure 8 to 10 in. in diameter.
Knowing the basics of pump repair can simplify preventive maintenance.
What is the secret to continuously baking or processing cakes, pizza, chicken, beer and thousands of other foods and beverages? Mechanical carbon materials used in the food processing equipment produce these foods safely and cost effectively.
Q. Our pumps take their suction from an open tank. When the liquid level drops, surface vortices are formed that allow air to be drawn into the pumps. What changes can be made to the tank to correct this problem?
In this age of environmental consciousness, OEMs around the world are competing to build better, safer and greener machines. In striving toward such lofty goals, many industries are rediscovering a fundamental principle-magnetics.
Rolling bearings are precision machine elements found in a wide variety of applications. They are typically reliable even under the toughest conditions. Under normal operating conditions, bearings have a substantial service life, which is expressed as either a period of time or as the total number of rotations before the rolling elements or inner and outer ring fatigue or fail.
When evaluating bearing distress, the babbitted shoe surface is commonly the only area that is examined. Although a great deal of information can be extracted from the babbitt appearance, additional information exists elsewhere.
For more than 100 years, machine parts composed of mechanical carbon have provided an alternative solution in applications where temperature and atmosphere prevent the use of oil-grease lubricants. Mechanical carbon materials contain graphite, which is relied on for its self-lubricating characteristics.
In December 2008, we discussed some reasons ball bearings run hot. In December 2006 (ref. [1]), we described the common pitfalls of incorrectly dimensioning shafts during repairs. This time, we will examine the cousin of a ball bearing-a roller bearing-and some of the pitfalls that occasionally cause hot operation.
Frequently, guide bearings are incorrectly blamed for a problem that has nothing to do with the bearings. Unless the bearings have a material defect (which would be unusual), guide bearings do not cause pump problems. Rather, guide bearing failures are the result of other problems that the pump is experiencing.
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In this multi-part series, we will investigate several aspects of centrifugal pump efficiency.
First of Five Parts
Since the original publication of this draft standard in the January 2008 issue of Pumps & Systems, I have received feedback, encouragement, numerous questions and criticism. The draft listed three basic levels of repair.
The McGraw-Hill scientific dictionary [5] states that a volute is "a spiral casing for a centrifugal pump... designed so that speed will be converted to pressure."
