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. 30, 2007
Filed:
Aug. 25, 2005
Masahiro Matsumoto, Hitachi, JP;
Masamichi Yamada, Hitachinaka, JP;
Hiroshi Nakano, Hitachi, JP;
Keiji Hanzawa, Mito, JP;
Keiichi Nakada, Hitachinaka, JP;
Masahiro Matsumoto, Hitachi, JP;
Masamichi Yamada, Hitachinaka, JP;
Hiroshi Nakano, Hitachi, JP;
Keiji Hanzawa, Mito, JP;
Keiichi Nakada, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
IN a thermal type flow measurement apparatus, a heating element is disposed in a fluid passage and generates heat by a passage of a current through itself. A first thermal sensitive element is disposed adjacent upstream of the heating element in a direction of fluid flow to be measured. A second thermal sensitive element is disposed adjacent downstream of the heating element in the direction of fluid flow to be measured. The fluid passage is provided with the heating element, the first thermal sensitive element, and the second thermal sensitive element. The fluid passage has an asymmetric structure with respect to the direction of fluid flow. Means for measuring a difference of temperatures is sensed by the first and the second thermal sensitive elements to produce a voltage according to a fluid flow rate. Heat control means for controlling the passage of the current through the heating element so that a sum with weights of respective temperatures sensed by the first and the second thermal sensitive elements reaches a preset value.