| 摘要 |
PURPOSE:To immediately recognize the occurrence of a non-steady flow, by firmly adhering an acoustic microphone to the outer wall of a transportation pipe for the gravitationally descending flow of a moving layer and obtaining an output passed through a band-pass filter, and then, finding a mass flow rate at a steady flow by calculation. CONSTITUTION:A piezoelectric element microphone 3 is firmly adhered and fixed to the outer wall of a transportation pipe 1 for gravitational descending flow. The output of the microphone 3 is amplified by means of an amplifier 7. Then the amplified output is passed through a band-pass filter 8 for 10-20kHz, band- pass filter in the vicinity of 1kHz and level detector 9, and band-pass filter which passes the peak of non-steady flow spectra and level detector 10. A multiplier 11 inputs signal outputs of the band-pass filters 8 and 9, namely, values proportional to a particle velocity VS and high density rho and outputs rho.VS after operation. An indicator 12 which indicates a mass flow rate G indicates a signal from the filter 10 as a detect signal when a slip phenomenon appears. A mass flow rate regulator 13 compares a measured mass flow rate value with a set value and supplies a valve operating section 6 with its operating output. |
