The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 19, 2010
Filed:
Sep. 30, 2008
Yoshihiro Sukegawa, Hitachi, JP;
Noboru Tokuyasu, Hitachinaka, JP;
Hiroaki Hoshika, Hitachiomiya, JP;
Kaori Kashio, Sakura, JP;
Yoshihiro Sukegawa, Hitachi, JP;
Noboru Tokuyasu, Hitachinaka, JP;
Hiroaki Hoshika, Hitachiomiya, JP;
Kaori Kashio, Sakura, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A thermal flow meter corrects flow rate detection errors produced by vaporization of liquid phase components included in a gas to be measured. The thermal flow meter includes a correction circuitthat applies respectively different predetermined voltages to heating resistors consisting of first heating resistor Rhand second heating resistor Rhof a sensor element disposed in the gas to be measured to set a first temperature state and a second temperature state, calculates a first flow rate value Qof the gas to be measured in the first temperature state and a second flow rate value Qof the gas to be measured in the second temperature state, and calculates a flow rate correction value ΔQ based on a ratio (Q/Q) between the first flow rate value and second flow rate value or a fourth-power value (Q/Q)of the ratio to correct a flow rate of the gas to be measured.