| 摘要 |
<p>An aerosol sampler (10) comprises at least one U- tube (16) whose ends are fixed to a support (14), and through which the aerosol is caused to flow. Means (40) are provided to set the tube vibrating, and to measure its resonant frequency. The bend of the U-tube (16) acts as an impactor so aerosol particles larger than a cut-off size are trapped, causing a change in the measured frequency. A sampler (10) may include a number of such U-tubes (16-24) in series, with steadily decreasing cut-off sizes, so the aerosol particulate size distribution can be determined.</p> |
