The verification of dust-particle-counter in case of differences of particle shapes

Abstract

The objective of this thesis was to control a dust-particle-counter from the company Lighthouse, the Boulder Counter. It was to find indications of its ability to distinguish between spherical shaped particles and fibres. For that reason the Boulder Counter got compare twice. The first comparison happened with an automatically analysis made by the DustTrack. It is a device which monitors the mass concentration. The second comparison is done with a manual made analysis. Therefor was a passive sampling design which gave a direct view to the quantity of extra produced particles.

The tasks relied on the effect known as the Brownian motion. Under the right conditions this effect does provide a spatial equilibrium of particles as well as for their concentrations. Additionally all tasks have to be executed perfectly to maintain reproducibility and the accompanied statistical significance.

The results showed enormous discrepancies between the Boulder Counter and its comparison opponents. This fact prevented a precise analysis of the Boulder Counters ability to distinguish between fibres and spherical particles.

The findings indicated a detection limit for the Boulder Counter. It is not able to measure the particles accurately if its detection channels get flooded. This is a common nuisance in the optical detection technology. To conceive the scale of the Boulder Counters limitations a further research is recommended before an improved repeat of this task can be granted. Until then is adequate to use the Boulder Counter only in environments with as less as possible contamination.