Patent ID: 6505520
Filing Date: 2003-01-14
Classification: G01F

Abstract:
A method for the preparation of a thermal pulsed micro flow sensor, comprising:(A) preparing a microchannel to allow a fluid to flow through; (B) determining randomly a position for a most upstream thermal sensor in said microchannel; (C) determining a position for a most downstream thermal sensor in said microchannel according to the following equation: &Dgr;F=(A*Ln)*{1/Tnâˆ’1/(Tn+&Dgr;T)}; wherein &Dgr;F represents accuracy in velocity measurement; A represents cross sectional area of the fluid channel; Tn is flying time and Tn=(A*Ln)/F wherein F represents full scale of measurable velocity of nth thermal sensor and n represents number of thermal sensor counting from the most downstream one; and &Dgr;T represents tolerance of the thermal pulse signals; (D) calculating minimum measurable velocity (Fnmin) of said most downstream thermal sensor according to the following equation: Fnmin=(A*Ln)/R wherein R represents the required maximum response time; (E) determining whether a second thermal sensor next to said most downstream thermal sensor is needed by comparing Fnmin with a threshold; (F) outputting obtained L values, if no further thermal sensor is needed; otherwise, repeating said steps (C)-(E) by replacing F with the Fâˆ’1min value until no need of further thermal sensor is determined; and (G) positioning thermal sensors according to said determined positions.