Prefilter for coarsely dispersed dust particles

Status:

completed 12/2005

Aims:

The scope of the general dust limit value does not extend to coarsely dispersed particles. Should such particles be included by sampling, they may impair the accuracy of the measurement result. In order to avoid coarsely dispersed particles being filtered on the sample carrier during sampling, a prefilter was to be developed which supplements the PGP personal sampling system of the BG Institute for Occupational Safety and Health (BGIA).

Activities/Methods:

Prototype prefilters were manufactured. The prefilters consist of a ring which can be placed and fixed upon the sampling head of the GSP-3,5 total dust sampling system. A hemispherical metal screen protrudes above the sampling head. The mesh size should be varied as required. Coarse particles were to be filtered off during sampling and thus prevented from reaching the intake of the suction cone. The prototypes were tested in comparative measurements (GSP-3, 5 with and without prefilter) in various working environments. Besides measurements in the textile industry, the device was also used in other industrial areas (e. g. paper processing and woodworking industries).

Results:

The new prefilter for coarsely dispersed dust particles prevents these particles with an aerodynamic diameter substantially greater than 100 µm from reaching the sampler. Areas of application include measurements relating to the use of woodworking machines (e.g. moulding machines), the removal of old coatings by sandblasting, raw cotton processing, the polishing of surfaces by means of copper wool, and the manufacture and processing of paper. Dust tunnel tests have yet to be performed for further evaluation of the prefilter.

Further informations:

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