Measuring and testing – Volume or rate of flow – Thermal type
Patent
1994-06-01
1996-02-27
Chilcot, Richard
Measuring and testing
Volume or rate of flow
Thermal type
7320414, G01F 168
Patent
active
054939062
ABSTRACT:
An electrical control circuit for a constant temperature anemometer includes a first operational amplifier coupled to receive inputs from two intermediate terminals of the Wheatstone bridge, and to generate an output voltage in response to a difference in voltage between the intermediate terminals. A second operational amplifier receives the output voltage, and provides its output as a drive voltage to the Wheatstone bridge. The second operational amplifier also provides its output to a feedback loop which incorporates an A/D converter, a digital processor and a D/A converter. The amplifier analog output is converted to a digital signal. The digital processor calculates a digital offset value, based on a constant ratio of the digital offset value/digital signal, predetermined by selection and setting of the various control circuit components. The D/A converter converts the digital offset value to an offset voltage provided to the second operational amplifier as an input. Thus, the second amplifier output is continuously and automatically modified by the appropriately calculated offset voltage, which leads to circuit stability and reliability over a much wider frequency bandwidth.
REFERENCES:
patent: 4523462 (1985-06-01), Kolodjski
patent: 4854176 (1989-08-01), Czarnocki et al.
patent: 5122756 (1992-06-01), Nelson
Article entitled "Recent Researches on Experimental Turbulence in Peking University" (pp. 82, 88, 89, 95).
Proceedings of the International Conference on Fluid Mechanics and Theoretical Physics, Beijing, China, by Zhonglei, et al published Jun. 6, 1992.
IFV-900 Article (Chinese), vol. 9, No. 4, Dec. 1992 (pp. 14-18).
IFV-900 Brochure (Chinese), Sep. 1992.
Article entitled "A Method for Determination and Control of the Frequency Response of the Constant-Temperature Hot-Wire Anemometer" in Journal of Fluid Mechanics by N. B. Wood, vol. 67, pp. 769-786, 1974.
Article entitled "A Study of the Constant-Temperature Hot-Wire Anemometer" in Journal of Fluid Mechanics by A. E. Perry, et al, vol. 47, pp. 577-599, 1971.
Article entitled "The Dynamic Response of Constant Resistance Anemometers" in Scientific Instruments of The Institute of Physics and the Physical Society, by M. R. Davis, vol. 3, pp. 15-20, Jan. 1970.
"Use of Shaped Gain Feedback in Constant Temperature Thermal Anemometers" by Peter Freymuth, Dept. of Aerospace Engineering Sciences, University of Colorado, Boulder, Colorado (pp. 15-1-15-5): 1981.
"Off-Optimum Operation of Hot-Wire Anemometers and Analysis of an Anemometer with Shaped Bridge Impedance" in vol. 3 of Various Sensor Applications, pp. 38-51, by Peter Freymuth.
Sensors & Systems '82 Pasadena Conference, May 18-20.
Chilcot Richard
Niebuhr Frederick W.
Patel Harshad
Peking University
LandOfFree
Automatic offset control for constant temperature anemometer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatic offset control for constant temperature anemometer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic offset control for constant temperature anemometer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1671727