US 6,983,214 B2 | ||
Flow rate measuring method and flow-meter | ||
Kenichi Hiraizumi, Ageo (Japan); Atsushi Koike, Ageo (Japan); and Hiromitsu Miyajima, Ageo (Japan) | ||
Assigned to Mitsui Mining & Smelting Co., Ltd., Tokyo (Japan) | ||
Appl. No. 10/344,033 PCT Filed Aug. 10, 2001, PCT No. PCT/JP01/06923 § 371(c)(1), (2), (4) Date Feb. 06, 2003, PCT Pub. No. WO02/14799, PCT Pub. Date Feb. 21, 2002. |
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Claims priority of application No. 2000-243226 (JP), filed on Aug. 10, 2000. | ||
Prior Publication US 2003/0167837 A1, Sep. 11, 2003 | ||
Int. Cl. G01F 1/12 (2006.01) |
U.S. Cl. 702—100 | 11 Claims |
1. A method of measuring a flow rate of fluid by:
moving the fluid within a fluid flow path,
measuring an electrical output corresponding to the flow rate of the fluid within the flow path by utilizing an electrical
circuit having a thermal type flow sensor disposed in the fluid flow path and by measuring heat absorption of the fluid with
the thermal type flow sensor,
measuring a temperature of the fluid,
converting a value of the electrical output to a value of the flow-rate by utilizing a plurality of predetermined calibration
curves T1 to Tk (k is an integer greater than 1):
indicating a relationship between the electrical output of the electrical circuit and the flow rate of the fluid at a plurality
of discrete temperature values t1 to tk respectively, each of the calibration curves having discrete flow rate values in response to discrete electrical output values
EAR1 to EARj (j is an integer greater than 1), and
achieving a corrected flow rate value Ft corresponding to the temperature at the time of measurement on the basis of a value of the measured temperature and the calibration
curves by interpolation calculation,
wherein the interpolation calculation is carried out on the basis of a value of the measured electrical output and a measured
temperature value t by using the calibration curves Tn, Tn+1 (n is an integer smaller than k−1) satisfying tn ≤t <tn+1 to achieve flow rate values Fab, FAB, which correspond to the measured electrical output value Eh by using the following equations (1), (2):
Fab=(Fa−Fb)·(Eh−EARm)/(EARm+1−EARm)+Fb (1)
FAB=(FA−FB)·(Eh−EARm)/(EARm+1−EARm)+FB (2)
wherein m is an integer smaller than j−1, electrical output values EARm,EARm+1 satisfy EARm≤Eh≤EARm+1, and Fb, Fa are flow rate values on the calibration curve Tn for the electrical output values EARm, EARm+1 respectively, and FB, FA are flow rate values on the calibration curve Tn+1 for the electrical output values EARm, EARm+1 respectively,
and to achieve the corrected flow rate value Ft corresponding to the measured electrical output value Eh for the measured temperature value t by using the following equation (3):
Ft=(Fab−FAB)·(t−tn+1)/(tn−tn+1)+FAB (3).
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