You have probably noticed that there are several camps out there when it comes to centrifugal pump applications involving variable frequency drives (VFDs). One group believes that every pump should have one, while another thinks that they should be banned altogether. And, of course, there is the middle ground that says it depends upon the pump and application.

Pumps & Systems, April 2007

In most training exercises or general discussions of pump-system interactions, great simplifications are made. The two most common examples presented are usually two pumps operating in parallel, or two pumps operating in series. Discussion rarely involves more than two pumps, and operation of a single pump against a multi-branched system is discussed even less frequently.

Pumps & Systems, April 2007

Have you ever experienced this? The pump that you purchased for one specific performance is placed in service and operates at another point that is completely different from its original design point or BEP. Here's one way to resolve this problem.

Pumps & Systems, April 2007

Once upon a time, in power plant fuel oil transfer and injection services, it was difficult to justify replacing twin screw timed pumps when maintenance was already familiar with the equipment. Not anymore. Reengineered screw pumps have become drop-in replacements for twin screw timed pumps.

Pumps & Systems, April 2007

Most industrial centrifugal pumps carry a significant capital equipment value. Maintaining them to run close to their best efficiency point (BEP) saves in downtime, repair costs, and overall power consumption. Proactive maintenance extends the useful life of a pump, reduces breakdowns, increases longevity and reliability, and extends the mean time between failure.

Pumps & Systems, April 2007

A well-engineered and properly installed submersible pump or dry-pit pump is one of the most reliable and trouble-free components of any water or wastewater pumping system. However, as with any mechanical device, the day will come when it does not operate properly and several questions must be addressed:

1. Can the problem be identified? 
2. Can the problem be fixed?
3. How much will it cost?

Pumps & Systems, April 2007

Rotary screw pumps have existed for many years and are manufactured around the world. More demanding service requirements impose challenges on screw pump manufacturers to provide higher pressure or flow capability, better wear resistance, improved corrosion resistance, improved efficiencies and lower leakage emissions. Better materials and more precise machining techniques, as well as engineering innovation, have led to improvements in all these areas. 

Pumps & Systems, April 2007

To quickly identify, select and perform effective PM tasks, plants must (1) identify high-risk equipment, (2) develop efficient, effective tasks to manage the most likely failures and package those tasks into work orders, and (3) implement the orders into work control systems.

Pumps & Systems, April 2007

Sometimes standard methods of vibration analysis are not enough to provide a true picture of the health of a pumping system, especially in the early recognition of an under-lubricated machine component.

Pumps & Systems, April 2007

Magnetic drive pumps are now being applied to a wide variety of applications where they face new demands and must respond to new trends in the marketplace.

Trends

While these pumps are still firmly entrenched in corrosive chemical applications and applications involving difficult to seal fluids, magnetic drive pumps are being challenged to be more efficient and have enhanced characteristics, such as dry running capabilities and corrosion resistance in the most severe conditions - all under the specter of higher material costs.