4638251 Method and apparatus for measuring flow of non-homogeneous material in incompletely filled flow channels

Abstract

In the preferred and illustrated embodiment, a method and apparatus for measuring the flow of non-homogeneous materials in an incompletely filled channel is set forth. In one embodiment, a NMR (or ESR) flow meter arrangement including a magnet forming the requisite magnetic field H o across a flow channel is incorporated. The magnet cooperates with a coil providing an NMR or ESR output signal from selected specie(s) or sub-atomic patricles (i.e. nuclei or unpaired electrons) in the material in the flow stream. It is desirable for the signal to be representative of the total amount of material in the flow stream. This signal may be in error, unable to sort out prospective combined variations due to (1) incomplete filling of the sensing volume or (2) a non-homogeneous composition of material. A composition sensor coil inscribing a very small volume in selected portions of the flow channel is included to form an NMR output signal indicative of composition, the small volume being filled for that sensor. Its output signal thus determines one of the two variables, and is input to a data combining circuit to indicate the flow volume from the two signals.