Global Patent Index - EP 1315948 A2

EP 1315948 A2 2003-06-04 - SEVERAL GAS FLOW MEASURING DEVICES AND SIGNAL PROCESSING METHODS

Title (en)

SEVERAL GAS FLOW MEASURING DEVICES AND SIGNAL PROCESSING METHODS

Title (de)

VERSCHIEDENE GASDURCHFLUSSMESSVORRICHTUNGEN UND SIGNALVERARBEITUNGSVERFAHREN

Title (fr)

DISPOSITIF DE MESURE DU DEBIT GAZEUX ET PROCEDES DE TRAITEMENT DU SIGNAL S'Y APPLIQUANT

Publication

EP 1315948 A2 (EN)

Application

EP 00958063 A

Priority

  • CA 0001026 W
  • US 15246199 P
  • US 15246099 P
  • US 15248799 P
  • US 15246499 P

Abstract (en)

[origin: WO0118496A2] A gas flow receiver has a non-symmetrical-flow-inducing diaphragm mounted in a flow tube and causes non-symmetrical flow in the flow tube with an accentuated higher pressure near an upstream orifice than would be sensed in a corresponding cross-section of the flow tube and an accentuated lower pressure near a downstream orifice. A gas flowmeter using thermoanemometer-type transducers receiving gas flow from the upstream orifice is made immune to vibration or acceleration, for example, by arranging a pair of the transducers parallel to one another with the gas flow passing serially through them, but in opposite directions. The resulting transducer signals processed to cancel the effect of the vibration or acceleration. The transducer output is amplified by a noisy amplifier which injects a secondary signal prior to digital conversion using an ADC. The digital signal is averaged over a sampling period to obtain a sample having a level of precision greater than a minimum quantization value of the ADC. The sampling period is varied as a function of the transducer's analog signal amplitude, such that the sampling period is longer for lower amplitude values and is shorter for higher amplitude values. The sampling period variation provides signal filtering. Since the flowmeter has a non-linear response, a calibrated output signal representing flow is obtained by recording samples under a number of calibrated flows and obtaining an analytical solution for the non-linear function, using the analytical solution to obtain calibrated values for all sample values, and, in operation, looking up a calibrated value corresponding to a sample value.

IPC 1-7 (main, further and additional classification)

G01F 1/42; A61B 5/087; G01D 1/02; G01D 3/032; G01F 1/684; G01F 1/696; G01F 25/00; H03M 1/20

IPC 8 full level (invention and additional information)

G01F 1/00 (2006.01); A61B 5/087 (2006.01); G01D 1/02 (2006.01); G01D 3/032 (2006.01); G01F 1/42 (2006.01); G01F 1/68 (2006.01); G01F 1/684 (2006.01); G01F 1/696 (2006.01); G01F 7/00 (2006.01); G01F 25/00 (2006.01); H03M 1/20 (2006.01)

CPC (invention and additional information)

A61B 5/0878 (2013.01); G01F 1/42 (2013.01); G01F 1/684 (2013.01)

Citation (search report)

See references of WO 0118496A3

Designated contracting state (EPC)

AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

DOCDB simple family

WO 0118496 A2 20010315; WO 0118496 A3 20020912; AU 2000269752 A8 20010607; AU 6975200 A 20010410; CA 2422398 A1 20010315; EP 1315948 A2 20030604; JP 2003529051 A 20030930; KR 20030043951 A 20030602