Compressed Air Best Practices - April 2008 - (Page 23)

Compressed Air Industry PLASTICS BLOW-MOLDING | 04/08 | p Dedicated primary air compressors to each booster offers a very safe design as the low-pressure air supply will always be there for the booster or both will be off. The booster has very little chance of receiving too low entry pressure entry air with potential imaging results. It probably will not have optimum power efficiency Properly installed, a well designed central low-pressure compressed air supply collected together offers a great deal of flexibility and ability to optimize both low- and high-pressure electrical energy operating costs Primary low-pressure can be selected for performance and suitability rather than have the size limited by the booster inlet capacity. Larger horsepower well applied three-stage centrifugals will generally be more power efficient than smaller units During emergencies low-pressure rental compressors can be tied in without affecting the high-pressure air input Efficient low-pressure air supply will also improve the operating efficiency of the low-pressure system Boosters can be selected on operating performance rather than convenient sizing. The most commonly used boosters for these applications would be two-stage, double-acting, horizontal-balance opposed water-cooled reciprocating compressors Rise Above the Noise. Control the Air. Making lots of noise just doesn’t ﬂy. The G5 Delta Blower gives you reliable air ﬂow with low noise and vibration levels. ■ 65 –75dB(A) ranges ■ Side-by-side installation ■ Easy access to components Take control. Fly on over to aerzenusa.com and see the G5 Delta Blower. p p p p p Booster Size And Efficiency Usually a larger unit will be more power efficient. For example: p A typical 150 hp class, two-stage 7" & 4" x 74" unit at about 485 rpm will deliver about 648 scfm (.82VE) at 143 BHP, at 600 psig (5.74 scfm/kw) A typical 300 hp class, two-stage 9" & 6" x 9" unit at 429 rpm will deliver about 1884 scfm at (.90VE) 291 BHP at 600 psig (8.202 scfm/kw) p eG See th der and Pow at the ow Booth h Bulk S 5 4041. The larger reciprocating unit has a better VE (Volumetric Efficiency) and overall is 30% more power efficient (5.74 scfm/kW ÷ 8.202 scfm/kW). With the flexibility of a central low-pressure supply the proper booster selection can have a very positive impact. A single central low-pressure supply system requires careful piping and storage design. Be sure there is plenty of supply for both the low- and high-pressure requirements. All boosters should be equipped with low inlet pressure safety controls. The following Table 1 shows the relative efficiency of a three-stage, low-pressure centrifugal primary combined with 9" & 6" x 9" booster compared to traditional four-stage centrifugal and four-stage double acting reciprocating unit. Aerzen Delta Blower AerzenUSA.com Click or call to see the new G5 Delta Blower. AERZEN USA Corporation 108 Independence Way Coatesville, PA 19320 Phone (610) 380-0244 Fax (610) 380-0278 E-mail: inquiries@aerzenusa.com G5 One step ahead 23 http://aerzenusa.com http://AerzenUSA.com http://AerzenUSA.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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