Proceedings of The 11th International Conference on Research in Engineering, Science & Technology
JIS Performance Evaluation Testing for Automatic Dust Concentration Measuring Instrument: Effect of dust charge on measured value
Masashi Wada, *Masashi Tsuji, William Averdieck
The automatic measurements of dust concentration emissions is well developed technology which is commonly used in industrial processes. To make public use of such technologies for regulatory compliance purposes, a certification system in Japan is needed, and as a part of such effort, a series of JIS standards were developed in 2020. This study reports on the actual performance evaluation of JIS-compliant test equipment, and useful knowledge and practical issues obtained on the validation and operation to the standard. In particular, the problem of not being able to universally correlate results between gravimetric measurements and probe electrification type dust meters was analysed and found to be caused by variable charging of the test dust. The amount of charge on the test dust is influenced by the dust injection method and the geometry and design of the test section in the ducts was identified. Charging of the test dust, presumably owing to frictional charging between the agitator plate or the rectifying wire mesh, was observed. The dust charge was significantly affected by the dust concentration, although not by the velocity, and this relationship was found to be inversely proportional. While the change in dust charge undermined the linear relationship between the gravimetric measurements and the dust monitor readings, a linear relationship is possible and can be obtained by compensating for the effect of the differences in the amount of charge. For the probe electrification type dust meter, it is necessary to focus on changes in the dust charge when carrying out equivalence tests using a test duct.
Keywords: Particulate emission monitor; Performance evaluation test; Dust charge; JIS B-7996; JIS B-7997.