Compressed Air Best Practices - February 2008 - (Page 33)

Focus Industry BULK HANDLING | 02/08 | BY DOCTOR VACUUM As an auditor, compressed air vacuum generators are one of my favorite topics. These are devices that utilize compressed air to generate vacuum and have become an easy target in compressed air system studies. There are a number of factors that should be considered before these devices are either put in place or left in place. The reality is that there is an enormous population of vacuum generators being used successfully by industry. Applications range from pick and place to vapor extraction to bulk material handling and the number of installations is growing. Before proceeding with an installation utilizing these devices, there are two general issues to consider: efficiency and appropriateness. There are a few general operating characteristics that tend to make efficiency better or worse for venturi-style vacuum pumps. The first is operating vacuum level. The higher the required vacuum, the lower the comparative efficiency. If you only need a couple of inches of mercury, you are in far better shape (using vacuum generators) than if you need 22" of mercury. The second characteristic is high flow at high vacuum. Those applications that require high flow rates at higher vacuum levels are going to be far less efficient than electric- driven vacuum pumps that can deliver similar capacity. The efficiency gap closes somewhat in circumstances that require high flow at low vacuum. Also, any application that requires constant vacuum flow is typically better suited for electric vacuum pumps. A significant advantage for electric vacuum pumps is found in the central compressed air supply area. Compressed air-driven vacuum pumps each use quite a bit of compressed air; for proper operation Efficiency The efficiency issue is very clear. While I cannot say that electric-driven vacuum pumps are always a more energy efficient choice, I personally have yet to find a vacuum generator application that I couldn’t make more efficient by going electric. The pick-up in efficiency when switching from compressed air driven vacuum to electric-driven vacuum ranges from two to fifty times. A good rule of thumb average is that electric- driven vacuum pumps are four times more energy efficient than compressed air-driven vacuum generators. These kinds of numbers tend to make energy managers take serious notice of the potential savings, and as the costs for energy continue to rise, any approach to trim energy cost is important. www.airbestpractices.com 33 http://www.numatics.com http://www.numatics.com 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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