According to domestic and international literature and the authors several-year-old experiences , the problems about the designing, calculating and regulating of air flow measuring apparatus with multiple nozzles, which nowadays are widely used for air flow measurement in the laboratory, are described in detail.

The design,type selection,and application of air flow rate measuring system in Huaneng Qinbei Power Plant have been presented,the problems appeared in operation process of units being analysed,and retrofit of the air flow rate measuring facility be- ing carried out.