High purity gases used in semiconductor manufacturing, such as nitrogen, oxygen and argon, are usually transported in pipes under high pressure and high velocity conditions. To detect particulate contaminants in the gas, a representative aerosol sample must be extracted and delivered to the particle detector via a sampling tube for counting and sizing of the particles. Figure 1 is a schematic diagram showing a typical aerosol sampling system for such an application. The system consists of a sampling inlet for extracting an aerosol sample from the flowing gas stream and some vertical or horizontal tubing for delivering the aerosol to the particle detector. In some cases, the particle detector is operated at atmospheric pressure. An expansion chamber must then be included to reduce the gas pressure from that in the pipe to ambient. This is usually accomplished by a small restricting nozzle or orifice. This paper describes our research on the mechanics of aerosol sampling and transport in a high purity gas sampling system. Theoretical and experimental studies have been made on a fundamental level to enable the performance of such systems to be predicted.
|Original language||English (US)|
|Title of host publication||Unknown Host Publication Title|
|Number of pages||8|
|State||Published - Dec 1 1986|