Method for ascertaining at least one pipe wall resonance frequency, as well as clamp-on, ultrasonic, flow measuring device

Patent metadata

Field	Value
Publication number	US-11435219-B2
Application number	US-201615569178-A
Country	US
Kind code	B2
Filing date	Apr 26, 2016
Priority date	May 18, 2015
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

A method for ascertaining at least one pipe wall resonance frequency of a pipeline in the region of a measuring point by means of a field device of process measurements technology having at least a first ultrasonic transducer, which is placed on the pipeline at the measuring point, comprising steps as follows: providing a first transfer function Utransducer(f) at least of the first or a plurality of ultrasonic transducers located in the region of the measuring point; ascertaining a received spectrum Urec(f) from a received signal Urec(t) after transmission of an ultrasonic signal; ascertaining a second transfer function Umeasuring point(f) from the first transfer function Utransducer(f) of the first or the plurality of ultrasonic transducers and from the received spectrum urec(f), wherein the second transfer function Umeasuring point(f) is characteristic for the measuring point; and ascertaining the at least one pipe wall resonance frequency fres, especially a plurality of resonance frequencies, in the region of the measuring point by evaluating the second transfer function Umeasuring point(f) from step III, as well as a clamp-on, ultrasonic, flow measuring device, a method for ascertaining flow, a method for ascertaining a change of the measuring point and an identification device.

First claim

The invention claimed is:

1. A method for ascertaining at least one pipe wall resonance frequency of a pipeline in a region of a measuring point using a field device of process measurements technology having at least a first ultrasonic transducer and a second ultrasonic transducer, which are placed on the pipeline at the measuring point, comprising steps as follows:
wherein a substep before placing the transducers on the pipeline includes providing a first transfer function U transducer (f) by ascertaining a total transfer function, in that the first ultrasonic transducer and the second ultrasonic transducer are connected on their coupling surfaces with one another and the coupling surfaces are pressed against one another where a propagation of a sound signal through the first ultrasonic transducer and the second is recorded as a total transfer and converted into the frequency domain to become the first transfer function U transducer (f);
positioning the first ultrasonic transducer and the second ultrasonic transducer spaced apart along the pipeline;
providing the first transfer function U transducer (f) of the first ultrasonic transducer and the second ultrasonic transducer located in the region of the measuring point;
wherein the first ultrasonic transducer and the second ultrasonic transducer each comprise a coupling body with the coupling surface for contacting the pipeline,
ascertaining a received spectrum U rec (f) from a received signal U rec (t) after transmission of an ultrasonic signal;
ascertaining a second transfer function U measuring point (f) from the first transfer function U transducer (f) of the first or both of the ultrasonic transducers and from the received spectrum U rec (f), wherein the second transfer function U measuring point (f) is characteristic for the measuring point, wherein the second transfer function U measuring point (f) is determined by the sound transmission behavior of the pipeline; and
ascertaining for the pipeline having a pipe wall at least one pipe wall resonance frequency f res , in the region of the measuring point by evaluating the second transfer function U measuring point (f);
wherein the transfer functions are an acoustic spectrum of amplitude vs. frequency.

2. The method as claimed in claim 1 , wherein said providing step of the first transfer function U transducer (f) comprises a temperature and an angle independent frequency response; said angle independent frequency response refers to the angle of incidence of the ultrasonic signal from the ultrasonic transducer into the pipeline.

3. The method as claimed in claim 1 , wherein the field device of process measurements technology has at least one non-transitory data memory; and the first transfer function U transducer (f) of the first or both of the ultrasonic transducers is stored callably in the non-transitory data memory.

4. The method as claimed in claim 1 , wherein a plurality of first transfer functions U transducer (f) are provided for a number of temperatures or temperature ranges, and are stored in a non-transitory data memory.

5. The method as claimed in claim 1 , wherein for ascertaining a received spectrum U rec (f) from a received signal U rec (t) after transmission of an ultrasonic signal, a transmission of an ultrasonic signal by a sound producing element of the first ultrasonic transducer occurs; the signal propagates at least through one of the first and second ultrasonic transducers, at least twice through the pipe wall of the pipeline, through a fluid medium in the pipeline and a second time through the first or through the second ultrasonic transducer, and is received by the sound producing element of the first ultrasonic transducer or by a sound producing element of the second ultrasonic transducer as a received signal and is converted into the received spectrum U rec (f).

6. The method as claimed in claim 1 , wherein for ascertaining a received spectrum U rec (f) from a received signal U rec (t) after transmission of an ultrasonic signal, a transmission of an ultrasonic signal by a sound producing element of the first ultrasonic transducer occurs; the signal propagates exclusively through at least one of the first and second ultrasonic transducers, through the pipe wall of the pipeline and the second ultrasonic transducer, and is received by a sound producing element of a second ultrasonic transducer as received signal and converted into the received spectrum U rec (f).

7. The method as claimed in claim 1 , wherein: the ascertaining of the second transfer function U measuring point (f), which is characteristic for the measuring point, occurs by subtracting logarithmic amplitude spectra of the first transfer function U transducer (f) at least of the first or both of the ultrasonic transducers located in the region of the measuring point from the received spectrum U rec (f).

8. The method as claimed in claim 1 , wherein: the ascertaining of the pipe wall resonance frequency f res in the region of the measuring point occurs by ascertaining an amplitude maxima of an amplitude spectrum of the second transfer function U measuring point (f).

9. The method of claim 1 , further comprising:
a clamp-on mounting for the first and second ultrasonic transducer to the pipeline, and an evaluation unit, connected to at least one of the first and second ultrasonic transducers configured to perform the providing and ascertaining steps.

10. The method of claim 9 , wherein said evaluation unit is equipped for ascertaining at least one of flow rate and flow velocity according to a travel-time difference method.

11. The method of claim 9 , wherein said evaluation unit generates an exciter signal for at least one of the first and second ultrasonic transducers based on the at least one pipe wall resonance frequency.

12. The method of claim 1 , wherein an evaluation unit, ascertains the pipe wall resonance frequencies f res ; and wherein the evaluation ascertains unit flow rate or a flow velocity of a fluid medium.

13. The method of claim 1 , wherein the ascertained pipe wall resonance frequency provides at least one of amplitude and position in the spectrum to generate the second transfer function U measuring point (f) and a point is displayed along with a displayed desired value point where the difference between the points exceed and/or subcede is also displayed.

14. The method as claimed in claim 1 , wherein an evaluation unit for ascertaining pipe wall parameters is equipped to ascertain from the ascertained pipe wall resonance frequency at least one of a pipe wall thickness and a pipe wall material.

Assignees

• Flowtec Ag

Inventors

• Ploss Peter
• Rupitsch Stefan
• Bezdek Michal
• Frohlich Thomas
• Kissling Beat

Classifications

• G01F1/667

  Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters · CPC title

• G01N29/4472

  Mathematical theories or simulation · CPC title

• G01F25/10 Primary

  of flowmeters · CPC title

• G01F1/662 Primary

  Constructional details · CPC title

• G01N29/12

  by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} · CPC title