Chemical Processing - February 2008 - (Page 27)

To head off problems, institute a rigorous seal inspection and replacement program. Don’t automatically replace a failing seal with another of the same design. For example, if an oil analysis shows higher-than-anticipated ingress of contaminants, it may be time to upgrade the entire sealing arrangement (perhaps using a more chemically resistant material or adding elements to bolster the sealing system). Or, in cases of excessive wear, it may make sense to switch to a non-contact labyrinth seal design. Monitoring pump health Taking a more proactive approach to pump maintenance can play an important role in boosting uptime. So, it’s not surprising there’s increasing interest in condition monitoring. This involves regular measurement and analysis of key physical parameters such as vibration and temperature, and enables detection of pump system problems before they can result in unscheduled downtime, high repair or replacement costs, and lost productivity. Basic instruments can assess and report on vibration, temperature and other parameters. More advanced tools include online surveillance systems and software that can deliver real-time data for review and foster more timely remedial action should this become necessary. Many problems will manifest as vibration, which is widely considered the best operating parameter to judge pump-train condition. Vibration can detect problems such as imbalance, misalignment, bearing oil-film instabilities, rolling bearing degradation, mechanical looseness, structural resonance and a soft foundation. Vibration measurements are quick and fairly non-intrusive because pump equipment remain undisturbed. In addition, established industry standards identify vibration levels for specific types of equipment. A significant increase in “overall vibration” (the sum of all vibration within the frequency range of the instrument) compared to a baseline value will signal an impending problem, allowing it to be addressed before equipment failure occurs. A wide range of technologies from hand-held vibration monitoring tools such as low-cost vibration pens and overall vibration meters to more sophisticated portable data collectors and related instruments combining compact size with data storage capabilities (Figure 2) can handle data collection. Regular monitoring of temperature also can shed light on system conditions. It’s a useful indicator of mechanical condition or the load applied to a specific component such as a thrust bearing. For example, as a thrust bearing fails, friction causes its temperature to rise. Thermocouple sensors installed in the housing of a bearing and measuring temperature changes within the bearing or lubricant can send a signal about problems beginning to develop, enabling appropriate maintenance actions to be scheduled. The technology toolbox for condition monitoring also includes online surveillance systems. These perform round-the- http://www.sulzerchemtech.com http://www.sulzerchemtech.com

Table of Contents Feed for the Digital Edition of Chemical Processing - February 2008

Chemical Processing - February 2008 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor Nanoparticle Safety Raises Questions Take the Pressure Off Vacuum Systems Achieve Optimum Centrifugal Pump Performance Rethink Batch-Manufacturing Alarm Systems Dr. Gooddata Orlando Plant Pioneers HMI Migration Strategy Process Puzzler Plant InSites Equipment & Services Ad Index Product Spotlight/Classifieds End Point

Chemical Processing - February 2008

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