Optical fiber correlative flowmeter

Abstract

Abstract PURPOSE:To obtain a flowmeter utilizing the nature of an optical fiber by detecting a peak value based on a self-correlation from the return path output of two ways of optical fibers which are inserted into a pipeline at the right angle to the direction of the flow. CONSTITUTION:Two ways of optical fibers 11 for receiving a light output from a light source 10 are inserted into a pipeline 12 at the right angle to the direction of the flow to form a sensor section S. The return path output of fiber is converted into an electrical signal with a photoelectric converter 13 and after passed through a rectification circuit 15, compared with a constant voltage by means of a comparator circuit 16. Then, a self-correlation is derived with a correlation device 17 to detect a peak value in the correlation. With such an arrangement, although there is an amplitude modulation in a part of the optical fiber contacting a fluid caused by an oscillation frequency of the fluid resulting from a micro-bending loss attributed to the vibration thereof, the derivation of the peak value in the correlation enables the calculation of the flow velocity and the flow rate thereof thereby providing an optical fiber flowmeter with improved characteristic.

Inventors

• 👤 Kiyoharu Inao

Bibliographic Details