Process diagnostics

• US 20050011278A1
• Filed: 07/16/2004
• Published: 01/20/2005
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Brown, Gregory C., Karschnia, Robert J., Peluso, Marcos
• Granted Patent: US 7,290,450 B2
• Time in Patent Office: Days
• US Class Current: 73/861.180
• CPC Class Codes: G01F 1/666 by detecting noise and sounds generated by the flowing fluid
• CPC Class Codes: G01F 1/7082 using acoustic detecting arrangements
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/02872 Pressure
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/449 Statistical methods not provided for in G01N29/4409, e.g. averaging, smoothing and interpolation

Abstract

A diagnostic device for use in a industrial process includes monitoring electronics or diagnostic circuitry configured to diagnose or identify a condition or other occurrence in the industrial process. The system can be implemented in a process device such as a flowmeter, and in one example an acoustic flowmeter. A transducer can also be used and a frequency response, such as resonant frequency, can be observed.

Claims

1. An acoustic flowmeter for measuring a flow rate of a process fluid in a pipe section in an industrial process, the flowmeter comprising:

an acoustic sensing device configured to couple to the pipe section and adapted to measure a process noise;

monitoring electronics coupled to the acoustic sensing device and adapted to isolate acoustic patterns generated by vortices in the process fluid from the measured process noise, the monitoring electronics adapted to detect a change in the measured process noise and to generate an alarm signal based upon a detected change, the change being indicative of a failure or deterioration of equipment in the industrial process.

2. The acoustic flowmeter of claim 1 wherein the monitoring electronics comprises:

a transformation block adapted to transform the measured process noise into a process signature; and

a comparator adapted to compare the process signature to a stored reference signature to identify the change.

3. The acoustic flowmeter of claim 1 and further comprising:

an acoustic generator coupled to the pipe section and adapted to generate an acoustic signal within the pipe section.

4. The acoustic flowmeter of claim 3 wherein the acoustic generator is coupled to the monitoring electronics, wherein the monitoring electronics are adapted to initiate generation of an acoustic signal at a particular frequency by the acoustic generator.

5. The acoustic flowmeter of claim 1 and further comprising:

fixed equipment coupled to the pipe section, the fixed equipment generating process noise as the process fluid flows through the fixed equipment;

wherein the change is indicative of corrosion or fouling of the fixed equipment.

6. The acoustic flowmeter of claim 1 and further comprising:

a non-volatile memory buffer adapted to store the reference signature, the reference signature comprising a transformed process noise signal of process fluid flowing through the industrial process when components of the industrial process are functioning properly.

7. The acoustic flowmeter of claim 1 wherein the process noise comprises:

a signal composed of a plurality of frequencies.

8. The acoustic flowmeter of claim 1 and further comprising:

a neural network adapted to monitor comparisons between the measured process noise and the stored reference signature and to determine whether to generate an alarm signal based on the extent of deviation from the reference signature.

9. The acoustic flowmeter of claim 1 and further comprising:

an external input or local operator interface for configuring the predetermined limit.

10. The acoustic flowmeter of claim 1 wherein the pipe section is configured to couple to a heat exchanger.

11. The acoustic flowmeter of claim 1 including an active transducer.

12. The acoustic flowmeter of claim 1 including a temperature sensor.

13. The acoustic flowmeter of claim 1 including a structure to introduce vortexes in the process fluid.

14. A diagnostic device for detecting fouling and corrosion in process equipment comprising:

process equipment;

at least one detector for measuring a frequency response coupled to the pipe section;

an transducer coupled to the process element and adapted to excite the process element into resonance; and

a diagnostic circuit coupled to the at least one detector and the transducer, the diagnostic circuit adapted to trigger the process element into resonance via a command sent to the transducer and to process the measured frequency response from the at least one detector, the diagnostic circuit adapted to compare the measured frequency response to a stored reference frequency response and to produce a diagnostic signal indicative of health of the process equipment based on a deviation of the measured frequency response from the stored frequency response.

15. The diagnostic device of claim 14 wherein the deviation of the measured frequency response is indicative of a mass change of the process equipment.

16. The diagnostic device of claim 15 wherein the mass change is a loss of mass indicative of corrosion.

17. The diagnostic device of claim 15 wherein the mass change is a gain of mass indicative of build up.

18. The diagnostic device of claim 14 wherein the process equipment comprises:

a thermowell with a temperature sensor for measuring a process temperature of a process fluid.

19. The diagnostic device of claim 14 wherein the process equipment comprises:

a pipe section.

20. The diagnostic device of claim 14 wherein the process equipment comprises:

an obstruction extending into a fluid flow.

21. A method of monitoring health of fixed equipment in an industrial process comprising:

measuring a noise signal in a process fluid of the industrial process;

separating acoustic patterns associated with vortices from process noise in the measured noise signal;

calculating a process value based on the acoustic patterns and a noise signature based on the process noise;

comparing the noise signature to a stored reference signature; and

adding an alarm indication onto a flow measurement signal for transmission to a control center, if the noise signature deviates from the stored reference signature by more than a predetermined limit.

22. A diagnostic system adapted to detect fouling and corrosion of fixed equipment in an industrial process, the diagnostic system comprising:

a sensing device configured to measure a process variable and adapted to passively or actively detect process noise; and

monitoring circuitry coupled to the sensing device and adapted to identify a frequency change in the process noise.

23. A method of detecting corrosion or fouling of process equipment in an industrial process comprising:

exciting a mechanical device into resonance;

measuring a resonant frequency of the device; and

generating an alarm signal indicative of fouling or corrosion of the device based upon the resonant frequency of the device.

24. A device for diagnosing operation of a valve in an industrial process comprising:

a first pressure sensor adapted to measure on upstream or downstream pressure;

a second pressure sensor adapted to measure a pressure of pneumatic fluid used to control valve position; and

diagnostic circuitry configured to diagnose operation of the valve based upon the sensed pressure.

25. The device of claim 24 wherein the first pressure sensor is adapted to sense acoustic frequencies in the process fluid.