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:
Aug. 15, 2006
Filed:
Jan. 09, 2003
Rolf Luchsinger, Uster, CH;
Daniel Matter, Brugg, CH;
Philippe Prétre, Baden-Dättwil, CH;
Thomas Kleiner, Fislisbach, CH;
Rolf Luchsinger, Uster, CH;
Daniel Matter, Brugg, CH;
Philippe Prétre, Baden-Dättwil, CH;
Thomas Kleiner, Fislisbach, CH;
ABB Research LTD, Zurich, CH;
Abstract
The invention relates to a process and a device for thermal measuring the flow rate (v) of a fluid (). In conventional thermal sensors the heating power P is supplied in the form of rectangular pulses. According to the invention, the sensor means () are supplied by a heating control () with non-constant heating pulses having a sublinear build-up dynamics P(t). Thereby, a nonlinear behaviour of the threshold value time (t), until a threshold value temperature (T) is reached, as a function of the flow rate (v) can at least partially be compensated. Embodiments concern inter alia a build-up dynamics P(t) proportional to tand/or to a time-independent amplitude factor (1+R/R), wherein m is a Reynolds-number-dependent exponent and R, Rare thermal transfer resistances. The advantages are an improved precision, a shorter measuring time and an enlarged measuring range for the flow rate v.