Advertisement

Optical Particle Counter Operating Procedures, Calibration and Correlation Methods

  • Alvin Lieberman

Abstract

Data from any OPC are derived on the basis of a number of OPC design and operating parameters. Most operators assume that the data produced are valid for any material and under any circumstances. However, it must be realized that the OPC is not a primary measurement instrument. Even though it reports only the size for each particle and the number of particles observed, it responds to several parameters such as particle size, the ratio of particle to fluid refractive indexes, and particle shape. OPC response is affected by the fluid flow field from which the sample is produced. Response also varies with OPC optical and electronic design. The particle size data produced depend on several system parameters. These effects occur even when the OPC is operating at its best and has been recently calibrated. Therefore, the OPC is calibrated to a known standard material using an accepted and standard method. Further, when more than one OPC is used in a large cleanroom area, it may be necessary to control operation of the several instruments to assure that each one provides similar data in similar environments. Minor differences in response to particle properties can result in a large change in indicated particle concentration. It is advisable to carry out effective correlation procedures whenever more than one OPC is to be used in a single installation in order to minimize this problem. These procedures may include selection of OPC designs so that similar systems are used for this purpose, as well as verifying calibration of each OPC.

Keywords

Latex Particle Particle Counter Polystyrene Latex American National Standard Institute Sensor Resolution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. American National Standards Institute, 1972. Method for Calibration of Liquid Automatic Particle Counters Using “AC” Fine Test Dust, ANSI B93.28–1972. New York: American National Standards Institute.Google Scholar
  2. American Society for Testing and Materials, 1980a. Standard Practice for Determining Counting and Sizing Accuracy of an Airborne Particle Counter Using Near-Monodisperse Spherical Particulate Materials, ASTM F328–80. Philadelphia: American Society for Testing and Materials.Google Scholar
  3. American Society for Testing and Materials, 1980b. Standard Practice for Secondary Calibration of Airborne Particle Counter Using Comparison Procedures, ASTM F649–80. Philadelphia: American Society for Testing and Materials.Google Scholar
  4. American Society for Testing and Materials, 1987. Defining Size Calibration, Resolution and Counting Accuracy of a Liquidborne Particle Counter Using Near-Monodisperse Spherical Particulate Material, ASTM F658–87. Philadelphia: American Society for Testing and Materials.Google Scholar
  5. American Society for Testing and Materials, 1989. Test Method for Calibration of Liquid-Borne Particle Counters for Submicrometer Particle Sizing, ASTM F1226–89. Philadelphia: American Society for Testing and Materials.Google Scholar
  6. Caldow, R., & Blesener, J., 1989. A Procedure to Verify the Lower Counting Limit of Optical Particle Counters. Journal of Parenteral Science and Technology 43(4):174–178.Google Scholar
  7. Hartman, A. W., 1987. Standards for Particle Size. Proceedings of the Parenteral Drug Association International Conference on Liquidborne Particle Inspection and Metrology, May 1987, Arlington, VA.Google Scholar
  8. Kasper, G., & Wen, H. Y. On-Line Identification of Particle Sources in Process Gases. Proceedings of the 34th Institute of Environmental Science Annual Technical Meeting, pp. 485–490, April 1988, King of Prussia, PA.Google Scholar
  9. Kaye, B. H., 1989. A Random Walk through Fractal Dimensions. New York: VCH Publishers.MATHGoogle Scholar
  10. Lettieri, T. R., & Hembree, G. G., 1988. Certification of NBS SRM 1691: 0.3 μm-Diameter Polystyrene Spheres, NBSIR 88–3730. Gaithersburg, MD: U.S. National Bureau of Standards.Google Scholar
  11. Society of Automotive Engineering, 1978. Procedure for Calibration of and Verification of Liquid-Borne Particle Counter, Aerospace Recommended Procedure 1192B. Warrendale, PA: Society of Automotive Engineering.Google Scholar
  12. Verdegan, B. M., Thibodeau, L., & Stinson, J. A., 1990. Using Monodispersed Latex Spheres Dispersed in Nonpolar Liquids to Calibrate Particle Counters. Microcontamination 8(2):35–39, 64–65.Google Scholar
  13. Wen, H. Y., & Kasper, G., 1986. Counting Efficiency of Six Commercial Particle Counters. Journal of Aerosol Science 17(6):947–961.CrossRefGoogle Scholar

Copyright information

© Van Nostrand Reinhold 1992

Authors and Affiliations

  • Alvin Lieberman

There are no affiliations available

Personalised recommendations