| 摘要 |
PURPOSE:To enable measurement of a flow rate even when the fluid itself has no fluctuation, by rendering positively sufficient fluctuations required for correlation operation to the fluid from outside. CONSTITUTION:An oscillation transmitter 2 composed of a piezoelectric element, etc. is fitted to the outside of a pipe line 1 and driven by a noise generator 3. In addition, an oscillation receiver 5 is fitted to the outside of the pipe line 1, detecting the fluctuations of the fluid in the pipe line 1. A correlation operation unit 6 operating the cross-correlation number phi (gamma) of oscillation between two points of the pipe line 1 is provided and an output of the noise generator 3 and an output of the oscillation receiver 5 are led into the operation unit 6. And, in this unit 6, phi (gamma) of transmitted and received waves is operated. The results of the operation form two sharp peaks along the time axis gamma. The peak of gamma=gammam is formed since the fluctuations of the velocity of the fluid are transferred to the downstream along with the flow of the fluid, and therefore, the velocity v can be found from gammam. Thus, the flow rate is found from the product of the velocity v and the cross-sectional area of the pipe. |
