| 摘要 |
Apparatus for sampling gaseous exhaust emissions, on a constant flow basis. A centrifugal type extractor pump is used to draw gas through a critical flow venturi of predetermined flow rate. Exhaust emissions are diluted with air and the critical flow venturi acts as a constant volume flow device serving a metering function. Samples are taken and collected continuously during the test run, and are available to be analyzed for contaminants such for example as hydrocarbon, carbon monoxide and oxides of nitrogen.
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