| 摘要 |
A shallow cup of non-hygroscopic material has a central inlet opening in its base and a filter disc closing its open end, whereby a hollow capsule is formed. A separable two-part cassette contains the capsule, with the marginal area thereof clamped between the two parts. One part contains the cup and has an end wall provided with a central inlet port registering with the cup inlet, and the other part of the cassette covers the filter and has an end wall provided with a central outlet port. The filter forms one wall of a chamber between it and the end wall of the last-mentioned part of the cassette. After a period of filtering, the cassette is opened and the preweighed capsule is removed and weighed again to determine the amount of particulate matter captured by the capsule. |
