颗粒物再悬浮和检测系统的性能指标

Performance Indices of Particulate Matter Resuspension and Measurement Systems

系统地提出了颗粒物再悬浮和检测系统的性能指标,指标至少应包括5方面:颗粒物浓度稳定性、浓度调节平衡时间与连续运行时间、浓度可调范围、颗粒物采样均匀度、粒径分布的一致性.根据干粉气动再分散方法和气溶胶力学理论,集成了一款颗粒物再悬浮和检测系统,并按照指标评估了该系统.结果表明,浓度可调范围为0.1～12000mg/m3,连续运行时间至少可达1～7d,浓度调节平衡时间≤1min;浓度稳定性较好,各种运行状态对应的浓度相对标准偏差(RSD)的平均值≤10%;各采样点采样均匀度好,RSD≤1.5%;混合箱内颗粒物在空气动力学直径0～40μm范围内的粒径分布与待测粉尘一致.

The performance indices of resuspension and measurement systems were systematically brought forward. The indices should include five aspects at least, the stability of particles concentration, equilibrium time of concentration adjusting and continuous running time, adjustable range of concentration, sampling tmiformity of particles, and consistency of particles size distribution. A particulate matter resuspension and measurement system was designed according to the pneumatic redispersion of dry dust and mechanics theory of aerosol which is evaluated in terms of the indices. The evaluation result shows that the concentration of particles can be adjusted in the range of 0.1 - 12000 mg/m^3, the equilibrium time of concentration adjusting is less than 1 min, the continuous running time can reach 1 -7 d at least, the concentration is stable, and the average of concentration RSDs is less than 10% under various running states of system, the samples, from different sampling points within the uniform mixing chamber, get good uniformity, RSD≤l.5%, the particles size distribution in uniform mixing chamber can keep consistency with testing dust in the range of 0-40/μm for aerodynamic diameter.