MEASURING SYSTEM HAVING A MEASURING TRANSDUCER OF VIBRATION-TYPE

• US 20110161017A1
• Filed: 12/29/2010
• Published: 06/30/2011
• Est. Priority Date: 12/31/2009
• Status: Active Grant

• Current Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Original Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Inventors: Kumar, Vivek, Anklin, Martin
• Granted Patent: US 8,924,165 B2
• Time in Patent Office: Days
• US Class Current: 702/47
• CPC Class Codes: G01F 1/8413 means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
• CPC Class Codes: G01F 1/8418 motion or vibration balancing means
• CPC Class Codes: G01F 1/8427 detectors
• CPC Class Codes: G01F 1/8431 electronic circuits
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8477 with multiple measuring conduits
• CPC Class Codes: G01N 11/02 by measuring flow of the material

Abstract

The measuring system comprises: A measuring transducer of vibration-type, through which medium flows during operation and which produces primary signals corresponding to parameters, especially a mass flow rate, a density and/or a viscosity, of the flowing medium; as well as a transmitter electronics electrically coupled with the measuring transducer for activating the measuring transducer and for evaluating primary signals delivered by the measuring transducer. The measuring transducer includes at least one measuring tube for conveying flowing medium; at least one electro-mechanical, oscillation exciter for exciting and/or maintaining vibrations of the at least one measuring tube, a first oscillation sensor for registering inlet-side vibrations at least of the at least one measuring tube and for producing a first primary signal of the measuring transducer representing vibrations at least of the at least one measuring tube, and a second oscillation sensor for registering outlet-side vibrations at least of the at least one measuring tube and for producing a second primary signal of the measuring transducer representing vibrations at least of the at least one measuring tube. The transmitter electronics, in turn, delivers at least one driver signal for the oscillation exciter for effecting vibrations of the at least one measuring tube and generates, by means of the first primary signal and by means of the second primary signal, as well as with application of a Reynolds number, measured value representing a Reynolds number, Re, for medium flowing in the measuring transducer, a pressure difference, measured value, which represents a pressure difference occurring between two predetermined reference points in the flowing medium.

Claims

1. Measuring system, especially compact, measuring device and/or Coriolis, mass flow measuring device, for flowing media, especially media in pipelines, which measuring system comprises:

a measuring transducer of vibration-type, through which, during operation, a medium flows, especially a gas and/or a liquid, a paste or a powder or another flowable material, and which produces primary signals corresponding with parameters, especially a mass flow rate, a density and/or a viscosity, of the flowing medium;

as well as a transmitter electronics electrically coupled with the measuring transducer for activating the measuring transducer and for evaluating primary signals delivered by the measuring transducer;

wherein the measuring transducer includes;

at least one measuring tube for conveying flowing medium,

at least one electro-mechanical, oscillation exciter, especially an electrodynamic, oscillation exciter, for exciting and/or maintaining vibrations of the at least one measuring tube;

a first oscillation sensor for registering vibrations, especially inlet-side vibrations, at least of the at least one measuring tube and for producing a first primary signal of the measuring transducer representing vibrations, especially inlet-side vibrations, at least of the at least one measuring tube; and

a second oscillation sensor for registering vibrations, especially outlet-side vibrations, at least of the at least one measuring tube and for producing a second primary signal of the measuring transducer representing vibrations, especially outlet-side vibrations, at least of the at least one measuring tube; and

wherein the transmitter electronics;

delivers at least one driver signal for the oscillation exciter effecting vibrations of the at least one measuring tube, and,

generates, by means of the first primary signal and by means of the second primary signal as well as with application of a Reynolds number, measured value (X_Re) representing a Reynolds number, Re, for medium flowing in the measuring transducer a pressure difference, measured value (X<sub>Δ

p</sub>), which represents a pressure difference occurring between two predetermined reference points in the flowing medium.

2. Measuring system as claimed in claim 1, wherein each of the reference points is located within the measuring transducer, especially in such a manner, that a first of the two reference points is located on the inlet side and a second of the two reference points is located on the outlet side in the measuring transducer.

3. Measuring system as claimed in claim 1, wherein the Reynolds number, measured value is held internally in a volatile data memory provided in the transmitter electronics and/or is produced during operation by means of the driver signal and/or by means of at least one of the primary signals.

4. Measuring system as claimed in claim 1, wherein the transmitter electronics generates the Reynolds number, measured value by means of the driver signal.

5. Measuring system as claimed in claim 1, wherein the transmitter electronics generates the Reynolds number, measured value by means of the first primary signal and/or by means of the second primary signal.

6. Measuring system as claimed in claim 1, wherein the transmitter electronics generates the pressure difference, measured value with application of an internally held, especially internally held in a volatile data, memory, viscosity, measured value (X_η

), which represents a viscosity, η

, of medium flowing in the measuring transducer, especially a viscosity, measured value, produced during operation by means of the driver signal and/or by means of at least one of the primary signals.

7. Measuring system as claimed in claim 6, wherein the transmitter electronics generates the viscosity, measured value by means of the driver signal.

8. Measuring system as claimed in claim 7, wherein the transmitter electronics generates the viscosity, measured value also with application of the first primary signal and/or the second primary signal.

9. Measuring system as claimed in claim 6, wherein the transmitter electronics generates the Reynolds number, measured value with application of the viscosity, measured value (X_η

).

10. Measuring system as claimed in claim 1, wherein the transmitter electronics, for ascertaining the pressure difference, measured value by means of the first primary signal and by means of the second primary signal, generates a phase difference, measured value (X_Δ

p), which represents a phase difference, Δ

φ

₁, existing between the first primary signal and the second primary signal, especially a phase difference, Δ

φ

₁, dependent on a mass flow rate, {dot over (m)}, of medium flowing in the measuring transducer.

11. Measuring system as claimed in claim 1, wherein the transmitter electronics, for ascertaining the pressure difference, measured value on the basis of at least one of the primary signals and/or on the basis of the at least one driver signal, generates a frequency, measured value, which represents an oscillation frequency, f_exc, of vibrations of the at least one measuring tube, especially of bending oscillations of the at least one measuring tube executed about an imaginary oscillation axis imaginarily connecting an inlet-side, first measuring tube end of the measuring tube and an outlet-side, second measuring tube end of the measuring tube at a natural resonance frequency of the measuring transducer.

12. Measuring system as claimed in claim 1, wherein the transmitter electronics, for ascertaining the pressure difference, measured value (X_Δ

p) by means of the first primary signal and by means of the second primary signal, generates a mass flow, measured value (X_m), which represents a mass flow rate, {dot over (m)}, of medium flowing in the measuring transducer,

13. Measuring system as claimed in claim 12, in the case of which measuring system the transmitter electronics generates a mass flow, measured value (X_m) based on the relationship:

14. Measuring system as claimed in claim 1, wherein the transmitter electronics generates the pressure difference, measured value (X_Δ

p) with application of a density, measured value (Xρ

) representing a density, ρ

, of medium flowing in the measuring transducer, especially a density, measured value (Xρ

) held internally in a volatile data memory provided in the transmitter electronics and/or produced during operation by means of the driver signal and/or by means of at least one of the primary signals.

15. Measuring system as claimed in claim 14, in the case of which measuring system the transmitter electronics generates the density, measured value (X_ρ

) by means of the frequency, measured value (X_f), especially based on the relationship;

16. Measuring system as claimed in claim 1, wherein the transmitter electronics, for ascertaining the pressure difference, measured value (X_Δ

p) by means of the first primary signal and by means of the second primary signal, generates a flow energy, measured value (X_Ekin), which represents a kinetic energy, pU², of medium flowing in the measuring transducer, dependent on a density, ρ

, and a flow velocity, U, of medium flowing in the measuring transducer.

17. Measuring system as claimed in claim 16, in the case of which measuring system the transmitter electronics generates the flow energy, measured value (X_Ekin) based on the relationship:

18. Measuring system as claimed in claim 12, in the case of which measuring system the transmitter electronics generates the pressure difference, measured value based on the relationship:

19. Measuring system as claimed in claim 12, in the case of which measuring system the transmitter electronics generates the Reynolds number, measured value with application both of the mass flow, measured value (X_m) as well as also the viscosity, measured value (X_η

), especially based on the relationship;

20. Measuring system as claimed in claim 1, in the case of which measuring system the transmitter electronics, for ascertaining the pressure difference, measured value, generates a pressure drop coefficient, which represents a pressure drop across the measuring transducer, dependent on the instantaneous Reynolds number, Re, of the flowing medium, referenced to an instantaneous kinetic energy of the medium flowing in the measuring transducer, especially based on the relationship:

X_ζ

=K<sub>ζ

,1</sub>+K<sub>ζ

,2</sub>·

X_Re<sup>Kζ

,3</sup>,

wherein K<sub>ζ

,1</sub>, K<sub>ζ

,2</sub>, K<sub>ζ

,3</sub>, are earlier experimentally ascertained, measuring system parameters, especially measuring system parameters held internally as constants in a non-volatile data memory provided in the transmitter electronics.

21. Measuring system as claimed in claim 20, in the case of which measuring system the transmitter electronics generates the pressure difference, measured value with application of the pressure drop coefficients (X_ζ

), especially based on the relationship;

22. Measuring system as claimed in claim 1, wherein the transmitter electronics, with application of the pressure difference, measured value and on the basis of a first pressure, measured value (X_p1), which represents a first pressure, p_Ref, reigning in the flowing medium, especially a first pressure, measured value (X_p1), held internally in a volatile data memory provided in the transmitter electronics, especially a first pressure, p_Ref, upstream of an outlet end of the measuring transducer and/or downstream of an inlet end of the measuring transducer, especially a first pressure, p_Ref, measured by means of a pressure sensor communicating with the transmitter electronics and/or ascertained by means of the first and second primary signals of the measuring transducer and/or a static, a first pressure, p_Ref, generates a second pressure, measured value (X_p2), which represents a static second pressure, p_crit, within the flowing medium, especially a minimum static second pressure, p_crit, and/or a static second pressure, p_crit, classified as critical for the measuring system.

23. Measuring system as claimed in claim 22, wherein the transmitter electronics, with application of the second pressure, measured value (X_p2), generates an alarm, which signals, especially visually and/or acoustically perceivably, a subceeding, or falling beneath, of an earlier defined, minimum allowable static pressure in the medium;

and/or wherein the transmitter electronics, with application of the second pressure, measured value (X_p2), generates an alarm, which signals, especially visually and/or acoustically perceivably, an occurrence, especially an impending occurrence, of cavitation in the medium.

24. Measuring system as claimed in claim 1, which, for producing a pressure, measured value (X_p1) representing a static pressure reigning in the flowing medium, especially a static pressure upstream of an inlet end of the measuring transducer or downstream of an outlet end of the measuring transducer, further comprises a pressure sensor serving for registering a static pressure reigning in a pipeline conveying the medium and for communicating, during operation, with the transmitter electronics.

25. Measuring system as claimed in claim 1, wherein the transmitter electronics, with application of the pressure difference, measured value, generates an alarm, which signals, especially visually and/or acoustically perceivably, an exceeding of an earlier defined, maximum allowable drop of a static pressure in the medium flowing through the measuring transducer;

and/or

wherein the transmitter electronics, with application of the pressure difference, measured value, generates an alarm, which signals, especially visually and/or acoustically perceivably, a too high pressure drop caused by the measuring transducer in the medium.

26. Measuring system as claimed in claim 1, wherein the measuring transducer further comprises:

a measuring transducer housing with an inlet-side, first housing end, especially an inlet-side, first housing end with a connecting flange for a line segment, for example, a pipeline segment, supplying medium to the measuring transducer, and with an outlet-side, second housing end, especially an outlet-side, second housing end with a connecting flange for a line segment, for example, a pipeline segment, removing medium from the measuring transducer.

27. Measuring system as claimed in claim 26, wherein the inlet-side, first housing end of the measuring transducer housing is formed by means of an inlet-side, first flow divider including two, mutually spaced flow openings and the outlet-side, second housing end of the measuring transducer housing is formed by means of an outlet-side, second flow divider including two, mutually spaced flow openings, and

wherein the measuring transducer includes two, mutually parallel, measuring tubes for conveying flowing medium, of which a first measuring tube opens with an inlet-side, first measuring tube end into a first flow opening of the first flow divider and with an outlet-side, second measuring tube end into a first flow opening of the second flow divider, and a second measuring tube opens with an inlet-side, first measuring tube end into a second flow opening of the first flow divider and with an outlet-side, second measuring tube end into a second flow opening of the second flow divider.

28. Measuring system as claimed in claim 27, wherein the at least one electro-mechanical, oscillation exciter serves for exciting and/or maintaining opposite equal vibrations of the first measuring tube and the second measuring tube, especially bending oscillations of each of the measuring tubes executed about an imaginary oscillation axis imaginarily connecting the respective first measuring tube end and the respective second measuring tube end at a natural resonance frequency of the measuring transducer.

29. Measuring system as claimed in claim 28, wherein the first primary signal produced by means of the first oscillation sensor represents inlet-side vibrations of the first measuring tube relative to the second measuring tube and the second primary signal produced by means of the second oscillation sensor represents outlet-side vibrations of the first measuring tube relative to the second measuring tube.

30. Measuring system as claimed in claim 26, wherein the pressure difference, measured value represents a totally occurring pressure difference in the flowing medium from the first housing end to the second housing end, especially in such a manner that the first reference point for the pressure difference represented by the pressure difference, measured value is located in the inlet-side, first housing end of the measuring transducer housing and the second reference point for the pressure difference represented by the pressure difference, measured value is located in the outlet-side, second housing end of the measuring transducer housing.

31. Method for measuring a pressure difference arising within a flowing medium, said method comprising:

permitting the medium to flow through at least one measuring tube;

producing a Reynolds number, measured value representing a Reynolds number, Re, for the flowing medium, and

applying the Reynolds number, measured value for producing a pressure difference, measured value, which represents a pressure difference occurring between two reference points in the flowing medium, especially two reference points located within the measuring transducer.

32. Method as claimed in the claim 31, further comprising:

exciting the at least one measuring tube to vibrations, especially bending oscillations about an imaginary oscillation axis imaginarily connecting an inlet-side, first measuring tube end of the measuring tube and an outlet-side, second measuring tube end of the measuring tube; and

producing a first primary signal representing inlet-side vibrations at least of the at least one measuring tube as well as a second primary signal representing outlet-side vibrations at least of the at least one measuring tube.

33. Method as claimed in claim 32, further comprising at least one of:

applying the first primary signal and/or the second primary signal for producing the Reynolds number, measured value, especially also for producing a density, measured value representing a density of the flowing medium and/or for producing a mass flow, measured value representing a mass flow rate of the flowing medium;

producing a mass flow, measured value representing a mass flow rate of the flowing medium, especially by means of the first primary signal and by means of the second primary signal;

producing a density-measured value representing a density of the flowing medium.

34. Method as claimed in claim 33, further comprising:

applying the mass flow, measured value, the density, measured value as well as the Reynolds number, measured value for the producing the pressure difference, measured value.