February 2007 Issue

On July 16 last year, a high-speed centrifugal pump failed catastrophically at a large refinery in South America, causing production losses and costing a substantial amount of money for repairs. The inboard bearing of the pump lost lubrication, overheated, and seized up.
As applied to nuclear processes, balanced impellers are critical when pumping cooling liquids such as titanium dioxide saturated with helium gas. Gaseous liquids are highly unstable and can lead to "micro-cavitation."
A large refinery or power plant may operate up to a dozen units of the same design, all installed 20 or 30 years earlier.
Bearings perform vital roles in enabling optimized operation and service life of pumps used throughout industry.
Discharge recirculation, pipe strains and gas entrained in a liquid are discussed.
All electric motors (motors) have a housing that contains the working components of the motor.
Have you ever wondered why the pressure exerted by a column of liquid has absolutely nothing to do with its volume or, for that matter, the geometric shape of its container?
Last September, we spoke about the importance of pipe-to-piping alignment, evaluating actual numbers, and tabulating stress values as they approach yield stress of pipe at various values of misalignment. This time, we will discuss the effects of pump-to-motor misalignment, beyond hype or generalities, by numerically quantifying the conclusions.
I have seen, and I am sure you have too, countless examples of installed pumps that are poor hydraulic fits. These selection mistakes are called off-design pump selections, bad actors, misapplied pumps, etc.
Natural gas is a clean-burning energy source well suited as a boiler fuel, vehicle fuel, and heating residences as well as large structures.
Rolling element bearings are mechanically complex compared to plain bearings, but are indispensable in a large variety of functions.
Lip seals with dimensionally stable elements are a viable option when sealing some of the more difficult pump system applications.

Cahaba Media Group

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Upstream Pumping

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