Measuring system and method for measuring a measurement variable of a flowing fluid

Patent metadata

Field	Value
Publication number	US-11906335-B2
Application number	US-201917052460-A
Country	US
Kind code	B2
Filing date	Apr 11, 2019
Priority date	May 2, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A measuring system includes: a lumen forming a flow path and a flow obstruction arranged in the flow path for effecting a disturbance in a flowing fluid; a sensor arrangement adapted to produce a first sensor signal and a second sensor signal; and transmitter electronics. The transmitter electronics are adapted to receive both the first and second sensor signals and to convert such into first and second sensor signal sampling sequences approximating the first and second sensor signals, respectively, the transmitter electronics further adapted using a digital adaptive filter to ascertain from the first sampling sequence a filter coefficients set and therewith to form a z-transfer function for filtering the second sampling sequence such that the z-transfer function is determined by the filter coefficients set, the signal filter and the second sampling sequence to produce a wanted signal sequence, to produce therefrom digital measured values representing a measurement variable.

First claim

The invention claimed is:

1. A measuring system for measuring at least one measurement variable, changeable as a function of time, of a fluid flowing along a flow path with a predetermined flow direction, the measuring system comprising:
a tube arrangement comprising a lumen defining a first portion of the flow path, a second portion of the flow path disposed in a flow direction downstream of the first portion, and a third portion of the flow path disposed in the flow direction downstream of the second portion and a tube wall surrounding the lumen;
a flow obstruction arranged within the tube arrangement in the second portion of the flow path, the flow obstruction configured to effect a disturbance in the flowing fluid, the disturbance dependent on the at least one measurement variable and/or serving as a measurable effect dependent on the at least one measurement variable;
a first sensor arrangement configured to generate a first sensor signal having a first frequency spectrum influenced by the fluid flowing within the first portion;
a second sensor arrangement configured to generate a second sensor signal having a second frequency spectrum influenced by the fluid flowing within the third portion, the second frequency spectrum deviating from the first frequency spectrum and/or including at least one wanted component, the at least one wanted component including a spectral signal component influenced by the at least one measurement variable as regards at least one signal parameter; and
a transmitter electronics including a microprocessor and configured to:
receive the first sensor signal and convert such into a first sensor signal sampling sequence approximating the first sensor signal, the first sensor signal sampling sequence including a first sequence of digital sampled values, defined by S D1 [m]=S D1 [t m ·f s1 ], using a first sampling rate, defined by f s1 =1/(t m+1 -t m )=1/T s1 , from the first sensor signal at different sampling points in time, given by t n =n·T s1 ;
receive the second sensor signal and convert such into a second sensor signal sampling sequence approximating the second sensor signal, the second sensor signal sampling sequence including a second sequence of digital sampled values, defined by S D2 [n]=S D2 [t n ·f s2 ] using a second sampling rate, defined by f s2 =1/(t n+1 -t n )=1/T s2 , from the second sensor signal at different sampling points in time, given by t n =n·T s2 , such that the second sensor signal sampling sequence approximates at least one wanted spectral signal component of the second sensor signal influenced by the at least one measurement variable;
using a digital adaptive filter, ascertain from the first sensor signal sampling sequence a wanted signal filter coefficients set including a set of N filter coefficients;
using the wanted signal filter coefficients set, generate a first z-transfer function of a wanted signal filter, defined as:

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wherein w k are the filter coefficients, the wanted signal filter being a digital filter adapted to filter the second sensor signal sampling sequence such that the first z-transfer function of the wanted signal filter is determined by the wanted signal filter coefficients set;
generate a wanted signal sequence, using the wanted signal filter and the second sensor signal sampling sequence, the wanted signal sequence being a sequence of digital function values defined by:

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Assignees

• Flowtec Ag

Inventors

• Kirst Michael

Classifications

• G01F1/3259 Primary

  for detecting fluid pressure oscillations · CPC title

• G01F1/38

  the pressure or differential pressure being measured by means of a movable element, e.g. diaphragm, piston, Bourdon tube or flexible capsule · CPC title

• G01F1/42

  Orifices or nozzles · CPC title

• G01F1/66

  by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters · CPC title

• G01F1/8468

  vibrating measuring conduits · CPC title