Apparatus for and method of monitoring condensed water in steam pipes at high temperature

• US 9,404,891 B2
• Filed: 12/17/2013
• Issued: 08/02/2016
• Est. Priority Date: 03/09/2010
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Lih, Shyh-Shiuh, Lee, Hyeong Jae, Bar-Cohen, Yoseph, Bao, Xiaoqi
• Primary Examiner(s): Saint Surin, J M
• Application Number:
  US14/109,470
• Publication Number:
  US 20140107954A1
• Time in Patent Office: 959 Days
• Field of Search: 736/49, 702/54
• US Class Current: 1/1
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 2291/101 one transducer
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/4472 Mathematical theories or simulation
• CPC Class Codes: G01N 29/50 using auto-correlation techniques or cross-correlation techniques

Abstract

A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

Claims

1. A monitoring system for determining the status of a steam pipe, comprising:

a programmable computer which when operating under control of a set of instructions recorded on a machine readable memory performs the steps of;

controlling the emission of a probe ultrasonic signal having a frequency in the range of 2.25 Mega Hertz and above from an ultrasonic signal generator into a steam pipe;

receiving from an ultrasonic signal receiver an electrical signal representative of an ultrasonic response signal which is generated in said steam pipe in response to said probe ultrasonic signal;

processing said electrical signal by application of one or more of a filter, a moving average, a window, a transformation, a Shannon Energy Envelope and an autocorrelation method to produce a result representing a status of said steam pipe; and

performing at least one of recording said result, displaying said result, and transmitting said result to another system.

2. The monitoring system for determining the status of a steam pipe of claim 1, wherein said filter is selected from the group consisting of a low pass filter, a high pass filter and a band limit filter.

3. The monitoring system for determining the status of a steam pipe of claim 1, wherein said window is a predetermined searching window.

4. The monitoring system for determining the status of a steam pipe of claim 1, wherein said transformation is selected from the group consisting of a time to frequency domain transformation, Fourier Transform, a Hilbert Transform, and a Hilbert-Huang Transformation.

5. The monitoring system for determining the status of a steam pipe of claim 1, wherein said ultrasonic signal generator and said ultrasonic signal receiver are the same ultrasonic device.

6. The monitoring system for determining the status of a steam pipe of claim 1, wherein said programmable computer which when operating under control of a set of instructions recorded on a machine readable memory performs the additional step of converting said electrical signal from an analog signal to a digital signal.

7. The monitoring system for determining the status of a steam pipe of claim 1, wherein said result representing a status of said steam pipe includes information about liquid water in said stem pipe.

8. The monitoring system for determining the status of a steam pipe of claim 7, wherein said information about liquid water in said steam pipe is indicative of a depth of said liquid water.

9. The monitoring system for determining the status of a steam pipe of claim 7, wherein said information about liquid water in said steam pipe is indicative of at least one of a turbulent flow, of bubble generation, of cavitation, of a shock and of a vibration in said liquid water.

10. The monitoring system for determining the status of a steam pipe of claim 1, wherein said programmable computer is a general purpose programmable computer.

11. A non-transitory machine-readable medium having recorded thereon a set of instructions, said instructions comprising only non-volatile signals, which when operating on a programmable computer causes said programmable computer to perform the steps of:

controlling the emission of a probe ultrasonic signal having a frequency in the range of 2.25 Mega Hertz and above from an ultrasonic signal generator into a steam pipe;

receiving from an ultrasonic signal receiver an electrical signal representative of an ultrasonic response signal which is generated in said steam pipe in response to said probe ultrasonic signal;

processing said electrical signal by application of one or more of a filter, a moving average, a window, a transformation, a Shannon Energy Envelope and an autocorrelation method to produce a result representing a status of said steam pipe; and

performing at least one of recording said result, displaying said result, and transmitting said result to another system.

12. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said filter is selected from the group consisting of a low pass filter, a high pass filter and a band limit filter.

13. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said window is a predetermined searching window.

14. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said transformation is selected from the group consisting of a time to frequency domain transformation, Fourier Transform, a Hilbert Transform, and a Hilbert-Huang Transformation.

15. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said ultrasonic signal generator and said ultrasonic signal receiver are the same ultrasonic device.

16. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said programmable computer is caused to perform the additional step of converting said electrical signal from an analog signal to a digital signal.

17. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said result representing a status of said steam pipe includes information about liquid water in said stem pipe.

18. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 17, wherein said information about liquid water in said steam pipe is indicative of a depth of said liquid water.

19. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 17, wherein said information about liquid water in said steam pipe is indicative of at least one of a turbulent flow, of bubble generation, of cavitation, of a shock and of a vibration in said liquid water.

20. The non-transitory machine-readable medium having recorded thereon a set of instructions of claim 11, wherein said programmable computer is a general purpose programmable computer.