JIS Performance Evaluation Testing for Automatic Dust Concentration Measuring Instrument: Effect of dust charge on measured value
JIS Performance Evaluation Testing for Automatic Dust Concentration Measuring Instrument: Effect of dust charge on measured value
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发表时间：
2021
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通讯作者：
M. Wada;Masashi Tsuji;W. Averdieck
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作者：
M. Wada;Masashi Tsuji;W. Averdieck
粉尘浓度排放的自动测量是一项发达的技术，在工业生产过程中得到了广泛应用。为了使这些技术在符合法规的目的下公开使用，日本需要一个认证体系，作为这种努力的一部分，2020年制定了一系列JIS标准。本研究报告了符合jis标准的测试设备的实际性能评估，以及在标准验证和运行中获得的有用知识和实际问题。特别分析了重力测量结果与探针式电气化粉尘计结果不能普遍关联的问题，发现这是由试验粉尘的电荷变化引起的。试验粉尘的电荷量受粉尘喷射方式的影响，确定了风管中试验段的几何形状和设计。观察到试验粉尘的电荷，可能是由于搅拌板或纠偏钢丝网之间的摩擦电荷。粉尘浓度对粉尘电荷量有显著影响，但速度对粉尘电荷量无显著影响，且二者呈反比关系。虽然粉尘电荷的变化破坏了重力测量和粉尘监测读数之间的线性关系，但通过补偿电荷量差异的影响可以获得线性关系。对于探头通电式粉尘计，在使用试验风道进行等效试验时，需要关注粉尘电荷量的变化。
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.