Compressed Air Best Practices - February 2008 - (Page 11)

Focus Industry BULK HANDLING | 02/08 | On the Demand-Side To get the needed information, I used a flow meter and a pressure transmitter. I hot-tapped the 8" main where it entered the plant and installed an insertion-type thermal mass flow meter. I fed the output of the flow meter and the pressure transmitter through a PLC, The data we began to see was a real eye-opener. Parts of the trend looked like this: then into a laptop using System Control And Data Acquisition (SCADA) software to display and record the data. This setup allows realtime, high-resolution display and will record gigabytes of data. I later transferred the data to a spreadsheet for analysis. (An averaging pitot tube and the associated transmitters were later installed permanently.) Changes in the flow rate frequently exceeding the capacity of two compressors occurred in seconds — in this case, an increase of 1,300 scfm in 15 seconds, a doubling in less than three minutes. It became obvious that we needed to examine the demand side and correlate events in production with the observed changes in flow. The data displayed in this chart is the output of a Thermal Mass meter. Interestingly, an Averaging Pitot Tube provided smaller values for the peaks. The TM meter is a single point instrument; it takes a reading at a single point near the center of the pipe and applies an algorithm to compensate for the velocity profile. However, when flow increases very rapidly the velocity profile is momentarily distorted with a relatively higher velocity down the center of the pipe. The algorithm (at least in my meter) does not seem to compensate properly for this distorted profile and outputs a value that is artificially high. The averaging instrument is not susceptible to this phenomenon. FROM LITTLE TO BIG AND EVERYTHING IN BETWEEN • Air & Gas* Compressors and Boosters • 3 to 206 SCFM • Pressures from 200 to 6000 PSI • 3 to 125 Horsepower • Sound Attenuated Enclosures Available • Standard and Custom Designs • Mobile Designs Available *Inert gases and pipeline quality natural gas BAUER COMPRESSORS Inc. Telephone: 757-855-6006 • Telefax: 757-857-1041 E-Mail: sls@bauercomp.com • www.bauercomp.com/norfolk/industrialair www.airbestpractices.com 11 http://www.bauercomp.com/norfolk/industrialair http://www.bauercomp.com/norfolk/industrialair http://www.airbestpractices.com

Table of Contents Feed for the Digital Edition of Compressed Air Best Practices - February 2008

Compressed Air Best Practices - February 2008 Contents From the Editor Utility-Air News February Audit of the Month: Dense-Phase Transport System Wreaks Havoc on Compressed Air System Real World Best Practices: Material Conveying with Pneumatic and Vacuum Systems Industrial Vacuum Cleaners Use Compressed Air in Portland Cement Manufacturing Processes The Numatics Air Preparation Group The Ins and Outs of Vacuum Generators Dekker Vacuum Technologies Do Your Meetings Sabotage Your Profits? Resources for Energy Engineers Wall Street Watch Advertiser Index Job Market

Compressed Air Best Practices - February 2008

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