Patent ID: 6023969
Filing Date: 2000-02-15
Classification: G01F

Abstract:
A flow sensor for measuring a rate of flow of a fluid flowing through a conduit defining a flow path, said flow sensor comprising:a first temperature sensitive sensing element disposed in said fluid flow path and in contact with said fluid, said first sensing element being heated;a flow modulator assembly for periodically varying said fluid rate of flow in contact with said sensing element alternately from a maximum to a minimum level to thereby cause said sensing element to generate a cyclic signal indicative of the heat removed from said sensing element by said fluid flow;a detection system responsive only to a magnitude of said cyclic signal for extrapolating therefrom a mass flow rate of said fluid flow;a second temperature sensitive sensing element for generating a second cyclic signal indicative of the heat removed from said second sensing element by said fluid flow;said flow modulator assembly having a flow modulator member having a first opening forming a first flow passageway and a second opening forming a second passageway disposed generally orthogonally to said first flow passageway; anda motor for rotating said flow modulator member.