| 摘要 |
PURPOSE:To accurately measure a flow speed by removing the effect of concn. irregularity of a particulate material, by inputting the outputs of a plurality of detectors for detecting the passage of the particulate material to a correlation meter through a high band pass filter having proper cut-off frequency. CONSTITUTION:A plurality of detectors 2-1, 2-2 such as optical fiber are provided in the flow field of a particulate material or in the vicinity thereof so as to provide a proper interval therebetween to optically detect the passage of the particulate material. The detection signals thereof are converted to electric signals through photoelectric converters 3-1, 3-2 while said electric signals are passed through high band pass filters 9-1, 9-2 each having proper cut-off frequency to be inputted to a correlation meter 4. Said cut-off frequency is preset by a presetting device 10 on the basis of the estimated flow speed of the particulate material or the optical constant of the detector 2. The mutual correlation function of the detection outputs is calculated by the correlation meter to calculate the flow speed of the particulate material. |
