Patent ID: 9638649
Date: 2017-05-02
CPC Classifications: G01N

Claim:
1. A method for determining local changes of concentration of an admixture in a fluid flow, comprising: determining an empirical dependence of electrical resistivity of a fluid on concentration of the admixture, injecting the fluid containing the admixture through a measurement cell, wherein the measurement cell is made in the form of a tube of a dielectric material disposed between two electrodes in contact with the fluid and wherein a change of concentration of the admixture in time in the flow of the fluid at an inlet to the measurement cell is known, detecting electrical resistivity of the fluid in the measurement cell during the injection, determining a first change of concentration of the admixture in time in the measurement cell using the determined empirical dependence of electrical resistivity of the fluid on the admixture concentration, recovering an impulse response of the measurement cell by applying a deconvolution method, based on the determined first change of concentration of the admixture in time in the measurement cell, injecting through the measurement cell the fluid with an unknown change of concentration of the admixture in time in the flow of the fluid at the inlet to the measurement cell, detecting electrical resistivity of the fluid with the unknown change of concentration of the admixture in time in the measurement cell during the injection, determining a second change of concentration of the admixture in time in the measurement cell using the determined empirical dependence of electrical resistivity of the fluid on the admixture concentration, and determining the unknown change of concentration of the admixture in time in the flow of the fluid at the inlet to the measurement cell with the following equation: where τ is an integration variable, t is time, I(t) is the unknown change of concentration of the admixture in the fluid flow at the inlet to the measurement cell, R