Systems and methods for non-destructive testing of tubular systems

1. A method for non-destructive testing of an object, comprising steps of:

a. providing an acoustic pulse reflectometry (APR) system having a wideband transmitter, a pressure sensor and a mixed wave tube with length 2 L;

b. performing a calibration to obtain two calibration parameters, an exact acoustic excitation pulse form P 1 and a loudspeaker acoustic impulse response H i ;

c. attaching the object to the APR system and performing a measurement to obtain an object test result P M o ; and

d. using R 1 , H i and P M o to obtain an object impulse response H s ;

whereby the object impulse response reflects a status of the object.

2. The method of claim 1 , wherein the obtaining of P 1 includes performing a measurement selected from the group consisting of a measurement that measures P 1 while a semi-infinite tube serves as the object and a measurement on an object in which any faults are far enough from the connection to the mixed wave tube so that P 1 can be extracted from this measurement.

3. The method of claim 2 , wherein the obtaining of H i includes:

i. replacing the object with a rigid plug,

ii. carrying out a measurement with the rigid plug to obtain a value P M p , and

iii. extracting H i directly from P M p by a theoretical calculation that also uses the measured P 1 .

4. The method of claim 3 , wherein the extracting of H i directly from P M p by a theoretical calculation includes calculating H i using the formula

H

s

=

P

M

p

P

1

-

1

P

M

p

P

1

·

H

i

-

1

·

P

1

P

1

=

P

M

p

-

P

1

P

M

p

·

H

i

-

P

1

.

5. The method of claim 2 , wherein the obtaining of H i includes:

i. replacing the object with a rigid plug,

ii. carrying out a first measurement P M p with the rigid plug, and

iii. replacing the plug with a second object with a length L, the second object having a distal plugged end, carrying out a second measurement to obtain an added measurement P M p2 and calculating H i using P M p , P M p2 and P 1 .

6. The method of claim 5 , wherein the calculating of H i using P M p , P M p2 and P 1 includes using the formulas:

H

s

=

P

M

p

P

1

-

1

P

M

p

P

1

·

H

i

-

1

·

P

1

P

1

⁢

=

⁢

P

M

p

-

P

1

P

M

p

·

H

i

-

P

1

H

s

2

=

P

M

p

⁢

⁢

2

P

1

-

1

P

M

p

⁢

⁢

2

P

1

·

H

i

-

1

·

P

1

P

1

⁢

=

⁢

P

M

p

⁢

⁢

2

-

P

1

P

M

p

⁢

⁢

2

·

H

i

-

P

1

wherein H s 2 is the acoustic response of the second object.

7. The method of claim 1 , wherein the APR system further includes a data acquisition card (DAQ), a pre-amplifier and an amplifier, and wherein the step of performing the measurement on the object is preceded by a check to determine overflow/underflow conditions of the APR system, and, if overflow or underflow conditions are found, by adjusting gains of the DAQ, the pre-amplifier and the amplifier.

8. The method of claim 1 , wherein the using of P 1 , H i and P M o to obtain an object impulse response H s includes applying a separation algorithm to disentangle forward and backward propagating signals in order to obtain the true impulse response of the object.

9. The method of claim 8 , wherein the applying a separation algorithm includes using an equation

H

s

=

P

M

o

P

1

-

1

P

M

o

P

1

·

H

i

-

1

·

P

1

P

1

=

P

M

o

-

P

1

P

M

o

·

H

i

-

P

1

.

10. The method of claim 1 , wherein the object is selected from the group consisting of a pressurized object and a liquid filled object.

11. An acoustic pulse reflectometry (APR) system for non-destructive testing of a pressurized test object, comprising:

a. a wide band signal transmitter for providing source acoustic pulses;

b. a mixed wave tube for serving as conduit for the source pulses between the transmitter and object;

c. a pressure sensor equidistantly spaced between two opposite ends of the mixed wave tube and used for sensing impulse responses from the test and calibration objects; and

d. means for pressurizing the mixed wave tube, calibration and test objects, thereby enabling non-destructive testing of a pressurized object.

12. The system of claim 11 , wherein the means for pressurizing include means for introduction and removal of a substance selected from the group consisting of a pressurized gas and a pressurized liquid.

13. The system of claim 12 , wherein the pressurized liquid includes a liquid at atmospheric pressure.

14. An acoustic pulse reflectometry (APR) system for non-destructive testing of a test object filled with liquid, comprising:

a. a wide band signal transmitter for providing source acoustic pulses;

b. a mixed wave tube for serving as conduit for the source pulses between the transmitter and object;

c. a pressure sensor equidistantly spaced between two opposite ends of the mixed wave tube and used for sensing impulse responses from the test and calibration objects; and

d. means for introducing and removing a liquid into or from the mixed wave tube, calibration and test objects, thereby enabling non-destructive testing of a liquid filled object.

15. A method for calibrating an acoustic pulse reflectometry system that can be used to non-destructively measure an object, the method comprising steps of:

a. measuring the acoustic excitation pulse form f 1 as emitted by the loudspeaker, and;

b. using the measured P 1 to determine a loudspeaker acoustic impulse response H i ,

whereby both P 1 and H i can be further used in determining non-destructively a status of a measured object.

16. The method of claim 15 , wherein the step of measuring P 1 includes performing a measurement selected from the group consisting of a measurement that measures P 1 while a semi-infinite tube serves as the object and a measurement on an object in which any faults are far enough from a mixed tube so that P 1 can be extracted from the measurement.

17. The method of claim 16 , wherein the using the measured P 1 to obtain H i includes:

i. replacing the semi-infinite tube with a rigid plug,

ii. carrying out a measurement with the rigid plug to obtain a value P M p , and

iii. extracting H i directly from P M p by a theoretical calculation that also uses the measured P 1 .

18. The method of claim 16 , wherein the using the measured P 1 to obtain H i includes:

i. replacing the semi-infinite tube with a rigid plug,

ii. carrying out a first measurement P M p with the rigid plug, and

iii. replacing the plug with a second object with a length L, the second object having a distal plugged end, carrying out a second measurement to obtain an added measurement P M p2 and calculating H i using P M p , P M p2 and P 1 .

19. The method of claim 17 , wherein the extracting of H i directly from P M p by a theoretical calculation includes calculating H i using the formula

H

s

=

P

M

p

P

1

-

1

P

M

p

P

1

·

H

i

-

1

·

P

1

P

1

=

P

M

p

-

P

1

P

M

p

·

H

i

-

P

1

.

20. The method of claim 18 , wherein the calculating of H i using P M p , P M p2 and P 1 includes using the formulas:

H

s

=

P

M

p

P

1

-

1

P

M

p

P

1

·

H

i

-

1

·

P

1

P

1

=

P

M

p

-

P

1

P

M

p

·

H

i

-

P

1

H

s

2

=

P

M

p

⁢

⁢

2

P

1

-

1

P

M

p

⁢

⁢

2

P

1

·

H

i

-

1

·

P

1

P

1

⁢

=

⁢

P

M

p

⁢

⁢

2

-

P

1

P

M

p

⁢

⁢

2

·

H

i

-

P

1

wherein H s 2 is the acoustic response of the second object.