Compressed Air Best Practices - April 2008 - (Page 20)

| 04/08 Focus Industry PLASTICS BLOW-MOLDING | FOCUSED ON 40 BAR, OIL-FREE AIR FOR THE PET INDUSTRY Can you talk about energy efficiency in the design? Sure. When looking at energy efficiency we need to look at energy consumption at full loads and at partial or no load. Some blow-molders run consistently at full load while others (like converters) have quite a bit of downtime due to changing bottle sizes for different customers. If you compare our 1872 cfm, three-stage reciprocating compressor to a centrifugal compressor at full load, the centrifugal may use 90–100 kW more in energy. At partial loads, the centrifugal compressor can turn down to only 80% of load and then has to blow the rest to atmosphere. The three-stage reciprocating compressor is a load/unload machine, which consumes only 12% of power when unloaded. The centrifugal stays at full power when unloaded. Blowmolders often have idling air compressors due to: The AF three-stage oil-free reciprocating compressor design p p p p p Designing in excess capacity for peaks in production Filling lines getting jammed Labeling and air conveyor machines going down Changing bottle sizes Routine maintenance on air compressors Those promoting centrifugal compressors will say that three-stage reciprocating compressors have higher maintenance costs. Our customers have found that the energy savings they realize with our designs more than offset these costs. CO2 O kW What air quality do blow-molders need? The specifications call for ISO 8573.1 Quality Classes 1.4.1. This means particulate filtration of 1 micron, a pressure dew-point of 38 ˚F and oil removal to 0.01 ppm. We offer standard filter and refrigerated air dryer packages, which include all the 40-bar interconnecting piping along with the system. This simplifies the installation time and quality of the system. We have one customer who also wants oil vapor removal filters in all their systems to protect against oil vapors in case hydrocarbons are present in the ambient air. Drink and food bottlers cannot afford to have any odors of oil present in their packaging. This is why oil-free air compressors are the standard in the industry and why we don’t think using boosters (some being lubricated) along with lubricated screw compressors is a good idea. These systems depend upon impeccable performance and maintenance of the oil coalescing filters in the system to provide oil-free air. Unloaded three-stage reciprocating compressors consume only 12% of rated power 20 www.airbestpractices.com http://www.airbestpractices.com

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Compressed Air Best Practices - April 2008 Contents From the Editor Utility-Air News The Compressed Air Audit of the Month: Minimizing Blow-Molding Pressure Fluctuations AF Compressors: Focused on 40 Bar, Oil-Free Air for the PET Industry Real World Best Practices: PET Plants Using Boosters for High-Pressure Air Guaranteeing Audit ROI for Blow-Molders Managing Vacuum Pressure Differential Are You Taking Full Advantage of Pneumatic Valve Technology? Are You Strategic? Resources for Energy Engineers: Training Calendar & Product Picks Wall Street Watch Advertiser Index Job Market

Compressed Air Best Practices - April 2008

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