Pumps & Systems, February 2008

Editor's Note: This is the second part of a two-part series on Process Control. The first part, available in the January 2008 issue on www.pump-zone.com, discussed the P-proportional control-of PID. This month we'll look at I and D.

Last month, we ended our discussion of proportional control by saying there are times when P alone cannot provide the accuracy required by a process. Take, for example, a constant pressure booster system under VFD control. If changes in flow and the resulting change in pressure occurred gradually over a long period of time, the VFD could use proportional control to keep pressure constant.

Pumps & Systems, February 2008

A variable frequency drive (VFD) can be a valuable asset in reducing the life cycle costs in certain types of pumping applications. The traditional method of motor control in pumping applications is a low cost mechanical starter, which is essentially a large switch with a built-in motor protection device known as a thermal overload relay. A conscious decision to reduce upfront costs by using a mechanical starter may result in higher energy consumption, excessive component wear and poor power quality.

Pumps & Systems, February 2008

"An ounce of prevention is worth a pound of cure" may have been coined by process and plant engineers tired of repairing or replacing pumps. Pumps are often the most under-serviced pieces of equipment in process automation when it comes to maintenance and prevention best practices. Unfortunately, nothing moves without the humble pump, and a process becomes inefficient when a pump doesn't operate properly or completely shuts down. Many times the pump manufacturer is seen to be the problem, when in fact the process or the surrounding equipment configuration is the cause.

Pumps & Systems, February 2008

Consider a typical sewage collection system. At the initial point of discharge, water first flows (by gravity) into a network of (sloped down) drain pipes, which gradually intercept a larger main pipe. Eventually, all this water needs to be lifted to a sewage wastewater processing plant.

Pumps & Systems, February 2008

Challenges for the Pump Market

A recent marketing survey found that 84.0 percent of satisfied customers would "jump ship" for a better deal if an opportunity arose. With markets becoming increasingly globalized, customer retention has become a critical part of business strategy. Companies need to ask themselves: What reason can I give this customer to stay, even if my competitor offers a cheaper price? The keys lie in keeping customers loyal to brands and products and ensuring a consistently outstanding customer experience.

Pumps & Systems, February 2008

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.

Pumps & Systems, February 2008

Self-timing, two-piece timing gears have changed the timing procedure and increased the life cycle of twin screw pumps.

Old Technology Versus New Technology

In the past, timing gears were made with hardened gear teeth only. The bore was left soft so that the keyway could be cut to time the pumps. Possible problems included a wallowed out and oversized keyway, which caused the gear to move around, wear the shaft and require repairs. The bore also became oversized, and the gears became unusable for any further service. If the gear stripped the keyway, it quite often gaulded on the shaft and made the gears unusable for a second run. Even with a re-keywayed gear, a large gaping slot takes away from the alignment area of the bore.

Pumps & Systems, February 2008

The second article of this three-part series on "Dematerializing the Process" explores how future industrial process plants will address rising operating costs plus energy and environmental concerns.

Here's just a sampling of industrial market headlines: Experienced human capital is scarce. Raw material costs are escalating. Energy and the environment are becoming constraints on economic growth. Information technology is the primary economic driver. The process plant of tomorrow is minimally staffed. Manufacturing flexibility is required to customize products for rapidly changing market demands. Manufacturing efficiency is the key to sustainability. Consolidation, globalization and information integration have spawned an array of new and innovative management, sales and manufacturing strategies.

Pumps & Systems, February 2008

With pumps part of just about every manufacturing operation, proper functioning of entire facilities often relies on a single pump. 

Half of a plant's maintenance budget is very often spent on pumps, and pumps are commonly the single largest source of unplanned downtime. They have a significant impact on environmental compliance, product quality, mission assurance and, ultimately, the bottom line.

Pumps & Systems, February 2008

Your company has recently purchased a laser based alignment system. Your newly trained technicians are asked to align a critical process pump. You witness the alignment. They save the final alignment data. You review the data, but what does it mean? How does it compare to dial indicators? Why did they rotate both shafts when measuring the misalignment? Why are the numbers at the feet higher than you would like? How do you KNOW the alignment is good? The debate begins.