Patent ID: 9021878
Filing Date: 2015-05-05
Classification: A61B,G01F

Abstract:
1. An apparatus for measuring the volumetric rate of flow of a liquid having variable values of density and/or heat capacity through a conduit, said apparatus comprising the following components: a) a section of said conduit adapted to form at least one chamber in which a known volume of said liquid can be isolated and either held stationary or in which the velocity of said liquid is reduced significantly in relation to its velocity in the sections of said conduit on either end of said chamber; b) at least one heating or cooling element adapted to add or subtract a known quantity of heat to or from said liquid; and c) at least one temperature sensor adapted to measure the instantaneous temperature of said liquid; wherein, at least one of said heating or cooling elements and at least one of said temperature sensors is in thermal contact with said known volume of said liquid that is isolated and held stationary or is flowing with a reduced velocity, thereby allowing the value of the aggregate coefficient, which is equal to the density of said liquid multiplied by the specific heat capacity of said liquid, to be determined directly said measurements of the instantaneous temperature, said known volume of liquid that is isolated and held stationary or is flowing with the reduced velocity, and said known quantities of heat that are added to or removed from said known volume of liquid that is isolated and held stationary or is flowing with the reduced velocity; and wherein, at least one of said heating or cooling elements and at least one of said temperature sensors is in thermal contact with said liquid that is flowing through said conduit, thereby allowing said volumetric rate of flow to be determined directly from measurements of the rate at which heat is added to or removed from said flowing liquid, measurements of the instantaneous temperature of said flowing liquid, and said volume of said aggregate coefficient, without the use of individual empirical calibration of said apparatus with said liquid.