February 2008 Issue

The past may be prologue to the future, but the time between the two seems increasingly short. In the past, labor, capital and raw materials were considered the underpinnings of wealth creation. Today, real-time process knowledge and innovative management strategies have become far more important for creating value, as evident in the headlines above. Accordingly, the time for systemic change is now. . . the opportunity to reinvent industrial manufacturing and the products and services that surround it have never been greater since the beginning of the industrial revolution.
Since metal bellows products vary greatly in what they are able to offer, it is important to understand the benefits and trade-offs as they apply to your particular operation. Be sure to review your applications and select the metal bellows seal best suited to help you extend meantime between repair, standardize inventory and increase reliability.
Rubber expansion joints have been specified and successfully used for many years to accommodate pressure loads, relieve movement stresses, reduce noise, isolate vibration, compensate for misalignment after plants go on stream and prolong the life of pumps and other motive equipment.
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.
Maintenance and repair functions constitute a significant component of pumping system life cycle costs, especially in terms of energy consumption.
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.
Self-timing, two-piece timing gears have changed the timing procedure and increased the life cycle of twin screw pumps.
One of the first steps in shaft alignment preparation is to make sure that the machines are locked out and tagged out. If equipment is accidentally started while an alignment is being performed, serious injuries could occur.
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.
"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.

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Upstream Pumping Solutions

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