[Measuring cyclone for the evaluation of dust sampling instruments SPG 10 AND SPG 210].

For dust measuring instruments which are used in industrial hygiene-according to standards there were required certain limited controls of the measurements validity. There is, however, no testing tool available, suitable for the applicants, for a gravimetric dust measuring instrument. It is proposed a measuring cyclone for industrial routine, which can be prepared and graduated with little effort. Examinations of the instruments SPG 10 and SPG 210 so far have shown a close dependence between the volume flow and the resistance to flow of the specific dust filter. The volume flow, actually effective for the grain fraction's separation of the airborne dust into certain parts of coarse dust and lung damaging fine dust in the dust precipitator's first stage may be inadmissibly different from the nominal flow. It is therefore proposed in addition to the necessary check of the measuring devices to establish the relation between volume flow and filter covering for every instrument.