FLOW MEASURING DEVICE, AS WELL AS USE OF SUCH DEVICE AND METHOD FOR ASCERTAINING FLOW VELOCITY

• US 20150377691A1
• Filed: 09/19/2013
• Published: 12/31/2015
• Est. Priority Date: 09/28/2012
• Status: Active Application

• Current Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Original Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Inventors: Wiest, Achim, Brumberg, Oliver, Ceglia, Paul
• Granted Patent: US 10,281,316 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01F 1/66 by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
• CPC Class Codes: G01F 1/692 Thin-film arrangements
• CPC Class Codes: G01F 1/7082 using acoustic detecting arrangements
• CPC Class Codes: G01F 25/15 specially adapted for gas meters G01F25/11 - G01F25/14, G01F25/17 take precedence
• CPC Class Codes: G01F 7/00 Volume-flow measuring devices with two or more measuring ranges; Compound meters

Abstract

A flow measuring device for ascertaining a corrected measured value of a flow velocity and/or a corrected mass flow of a medium, especially a gas, in a measuring tube, including: an apparatus for ascertaining a first measured value of flow velocity and/or mass flow of the medium by thermal, mass flow measurement; an apparatus for ascertaining velocity of sound and/or frequency dependent damping of an acoustic signal, especially an ultrasonic signal, in the medium and/or an apparatus for ascertaining an optical, wavelength dependent absorption of an optical and/or excited fluorescence of the medium, and an evaluation unit for correcting the ascertained first measured value of mass flow or flow velocity based on the ascertained sound velocity values and/or the frequency dependent, ascertained damping values of the acoustic signal and/or the ascertained absorption values of the optical signal and/or the florescence values of the medium, and method for ascertaining a corrected measured value of flow velocity and/or mass flow, and use of the device and method.

Claims

1-16. -16. (canceled)

17. A flow measuring device for ascertaining a corrected measured value of flow velocity and/or a corrected mass flow of a medium, especially a gas, in a measuring tube, comprising:

an apparatus for ascertaining a first measured value of flow velocity and/or mass flow of the medium by thermal, mass flow measurement,

an apparatus for ascertaining velocity of sound and/or frequency dependent damping of an acoustic signal, an ultrasonic signal, in the medium and/or an apparatus for ascertaining an optical, wavelength dependent absorption and/or excited fluorescence of the medium; and

an evaluation unit for correcting the ascertained first measured value of mass flow or flow velocity based on the ascertained sound velocity values and/or the frequency dependent, ascertained damping values of the acoustic signal and/or the ascertained absorption values of the optical signal and/or the florescence values of the medium.

18. The flow measuring device as claimed in claim 17, wherein:

said apparatus for ascertaining a first measured value of flow velocity and/or mass flow of the medium by thermal, mass flow measurement and said apparatus for ascertaining the velocity of sound and/or the frequency dependent damping and/or the ascertained optical properties of the optical signal are arranged in one housing.

19. The flow measuring device as claimed in claim 17, wherein:

said apparatus for ascertaining the velocity of sound and/or the frequency dependent damping is part of an apparatus for ascertaining the flow velocity of the medium based on the travel-time difference method.

20. The flow measuring device as claimed in claim 17, wherein:

said apparatus for ascertaining the velocity of sound and/or the frequency dependent damping is embodied as a clamp-on sensor.

21. The flow measuring device as claimed in claim 17, further comprises:

an apparatus for ascertaining pressure of the medium located in the measuring tube.

22. The flow measuring device as claimed in claim 17, further comprising:

an apparatus for ascertaining electrical capacitance of the medium located in the measuring tube.

23. The flow measuring device as claimed in claim 17, wherein:

said evaluation unit is supplementally provided for ascertaining thermal conductivity, density, moisture content, temperature and/or composition of the medium based on the ascertained sound velocity values, the frequency dependent, ascertained damping values of the acoustic signal and/or the ascertained optical properties of the medium, the pressure and/or the electrical capacitance of the medium located in the measuring tube (2, 12).

24. The flow measuring device as claimed in claim 18, wherein:

said housing with said apparatus for ascertaining the flow velocity and/or mass flow of the medium by thermal, mass flow measurement and said apparatus for ascertaining the velocity of sound and/or frequency dependent damping of the ultrasonic signal is embodied as a sensor element; and

said apparatus for ascertaining the velocity of sound and/or frequency dependent damping of the ultrasonic signal is embodied as an ultrasonic barrier and/or said apparatus for optical, wavelength dependent absorption and/or excited fluorescence of the medium is embodied as a light barrier.

25. The flow measuring device as claimed in claim 18, wherein:

said housing with said apparatus for ascertaining the flow velocity and/or mass flow of the medium by thermal, mass flow measurement and said apparatus for ascertaining the velocity of sound and/or frequency dependent damping of the ultrasonic signal and/or with said apparatus for optical, wavelength dependent absorption and/or excited fluorescence of the medium in the form of a light barrier is embodied as a sensor element with a longitudinal axis and comprises a medium contacting, sensor head, which sensor head has a lateral surface, which extends parallel to the longitudinal axis of said sensor element, and an end face, which extends perpendicular to the longitudinal axis of said sensor element.

26. The flow measuring device as claimed in claim 17, wherein:

said apparatus for ascertaining the flow velocity and/or mass flow of the medium by thermal, mass flow measurement includes at least two thin film, resistance elements, with at least one heatable, thin film, resistance element, which are arranged in such a manner that heat input through one of the thin film-resistance elements in the medium occurs mainly on an end surface segment.

31. Use of the flow measuring device or a method as claimed in claim 17 for determining flow velocity and/or mass flow of gases or gas mixtures.

32. Use of the flow measuring device or a method as claimed in claim 17 for determining composition and/or moisture content of gas mixtures.

27. A method for ascertaining a corrected measured value of a flow velocity and/or a mass flow of a medium in a measuring tube of a flow measuring device, comprising the steps of:

ascertaining the flow velocity and/or mass flow of the medium by thermal, mass flow measurement;

ascertaining velocity of sound and/or frequency dependent damping of an acoustic signal, especially an ultrasonic signal, in the medium and/or ascertaining a wavelength dependent absorption of an optical signal and/or excited fluorescence of the medium; and

correcting the ascertained mass flow or the ascertained flow velocity based on said ascertained sound velocity values and/or the frequency dependent, ascertained damping values of the acoustic signal and/or the ascertained absorption values of the optical signal and/or the florescence values of the medium.

28. The method as claimed in claim 27, wherein:

said ascertaining of the velocity of sound and/or frequency dependent damping of the acoustic signal occurs in a measuring interval from between 10 ms to 5 min, preferably 20 ms to 30 sec, especially preferably 100 ms to 5 sec.

29. The method as claimed in claim 27, wherein:

the ascertaining of the velocity of sound and/or frequency dependent damping of the acoustic signal is performed by a continuous correction via corresponding measurements with continuous wave ultrasound and measuring of phase and amplitude.

30. The method as claimed in claim 27, wherein:

the correcting of the ascertained mass flow or the ascertained flow velocity occurs by ascertaining a sound velocity- and/or damping dependent and/or ascertained optical property dependent, correction value, based on which a currently ascertained value of a mass flow or a flow velocity is corrected.

33. Use of a method as claimed in claim 27, for determining flow velocity and/or mass flow of gases or gas mixtures.

34. Use of a method as claimed in claim 27, for determining composition and/or moisture content of gas mixtures.