Keeping track of shrinking particles
08/01/2000
by Laureen Belleville
The trend toward miniaturization and other developments in modern industrial technology have necessitated unprecedented degrees of accuracy and reliability obtainable only in an extremely clean environment.
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Biotechnology laboratories and hospital operating rooms are renowned for their strict requirements. And in semiconductor production, all particles exceeding 0.1 micron must be eliminated. Higher standards of purity are also being applied to liquids—in the pharmaceutical industry or for hydraulic systems in the aerospace industry, for example.
The maintenance of uncontaminated environments becomes possible only through the careful analysis of concentrations, diameters and distributions of minute particles, both airborne and in liquid.
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Handheld airborne particle counter model 227 (Met One) (top). Handheld particle counter model HHPC-6 (ART Instruments) (bottom).
meet the ever increasing demands, particle counter manufacturers are forced to test the limits of their R&D. Advances in the sensor element of the particle counter include the application of diode-pumped solid-state laser (DPSSL) technology, which Pacific Scientific Instruments reports as more reliable than gas lasers.
 Manufacturers of Particle Counters |
"DPSSL technology eliminates the high-voltage supply required for HeNe gas lasers, yet provides more power, resulting in an instrument with stable sensitivity and high reliability. Using DPSSL technology, there is no gas leakage, no fragile glass tube, no lengthy light path—all of which are characteristics of gas lasers," the company explains.
However, Particle Measuring Systems Inc.'s Lasair model uses a passive cavity design employing a HeNe laser. According to Particle Measuring Systems, passive cavity systems are ten times less sensitive to power loss due to particle contamination on the critical optical components than active cavity systems.
 Manufacturers of Particle Counters (con't) |
Depending on the application, users can choose from small, handheld portable instruments or larger wall-mounted systems that are capable of collecting samples from different locations simultaneously. Some offer CRT displays presenting collected information in tabular or histogram format while others enable the user to transmit data collected through an Ethernet connection directly to a workstation for real-time analysis. Product enclosures are typically aluminum for lightweight portable designs or stainless steel for environmental and chemical compatibility.
Distributors of Particle Counters
The following companies distribute particle counters.
- Liberty Industries: East Berlin, CT, Ph: (860) 828-6361, Fax: (860) 828-8878, www.Liberty-Ind.com
- MGN International Inc.: Vista, CA, Ph: (760) 599-2626, Fax: (760) 599-2631, www.mgnintl.com
- Micro Equipment Company: Beaverton, OR, Ph: (503) 533-0719, Fax: (503) 439-8257
- Response Rentals: Ph: (800) 242-3910, Fax: (716) 424-2166, www.responserentals.com
- Terra Universal: Anaheim, CA, Ph: (714) 526-0100, Fax: (714) 992-2179, www.TerraUniversal.com
- Ultrapure Technology: Suwanee, GA, Ph: (800) 932-0309, Fax: (770) 932-0809, www.ultrapuretechnology.com
- VWR: West Chester; PA, Ph: (610) 429-2858, Fax: (610) 918-0310, www.vwrsp.com