Testing of a Personal Filter Cassette with a Circumferential Orifice

摘要

A new personal filter cassette with circumferential orifices for personal inhalable dust concentration measurements was tested using coal dust, and compared to standard closed face and open face cassettes. The new cassette has four orifices separated by small posts with a slot-like geometry located circumferentially around the side of the cassette filter holder. The collection of coal dust was sampled in a laminar flow chamber with the three types of cassettes at different orientations to the air flow. Uranine tagged potassium biphthalate particles were used to test the uniformity of distribution on the filter surface. The test results indicated that the circumferential cassette appears to give a uniform distribution of dust across the filter surface. As this surface is protected like the surface in the closed face cassette, this cassette may have some advantages over either of the other two.