U.S. patent application number 15/426234 was filed with the patent office on 2017-05-25 for sensor positioning with non-dispersive guided waves for pipeline corrosion monitoring.
The applicant listed for this patent is General Electric Company. Invention is credited to James Norman Barshinger, Wei Luo, Debasish Mishra, Anusha Rammohan.
Application Number | 20170146492 15/426234 |
Document ID | / |
Family ID | 50239150 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170146492 |
Kind Code |
A1 |
Luo; Wei ; et al. |
May 25, 2017 |
SENSOR POSITIONING WITH NON-DISPERSIVE GUIDED WAVES FOR PIPELINE
CORROSION MONITORING
Abstract
The ultrasonic sensor assembly is provided. The assembly
includes a first and second flexible sets of transducers wrapped
and permanently attached to the pipe at first and second locations,
respectively. Each set of transducers includes at least transducers
arranged in a row. The first set of transducers is configured to
transmit a wave along the pipe. The second set of transducers is
configured to receive the wave transmitted along the pipe. The
ultrasonic sensor assembly includes a controller operatively
connected to the second set of transducers for receiving
information about the wave received by the second set of
transducers. The controller is configured to analyze the
information about the wave received by the second set of
transducers to determine the presence of possible defects in the
pipe. An associated method is also provided.
Inventors: |
Luo; Wei; (Chandler, AZ)
; Barshinger; James Norman; (State College, PA) ;
Mishra; Debasish; (Bangalore, IN) ; Rammohan;
Anusha; (Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
50239150 |
Appl. No.: |
15/426234 |
Filed: |
February 7, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14956423 |
Dec 2, 2015 |
9588086 |
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15426234 |
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13747522 |
Jan 23, 2013 |
9228888 |
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14956423 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 2291/0289 20130101;
Y10T 29/49764 20150115; G01N 2291/0425 20130101; G01N 2291/02854
20130101; G01N 29/223 20130101; G01N 29/07 20130101; G01N 2291/106
20130101; G01N 2291/2634 20130101; G01N 29/041 20130101 |
International
Class: |
G01N 29/22 20060101
G01N029/22; G01N 29/07 20060101 G01N029/07 |
Claims
1. An ultrasonic sensor assembly for a pipe, the ultrasonic sensor
assembly comprising: a first set of transducers configured to be
attached to the pipe at a first location, the first set of
transducers being flexible and configured to wrap at least
partially around the pipe matching a shape of the pipe at the first
location, the first set of transducers being permanently attached
to the pipe, the first set of transducers including at least
transducers arranged in a first row, the first set of transducers
being configured to transmit a wave along the pipe; a second set of
transducers configured to be attached to the pipe at a second,
different location, the second set of transducers being flexible
and configured to wrap at least partially around the pipe matching
a shape of the pipe at the second location, the second set of
transducers being permanently attached to the pipe, the second set
of transducers including at least transducers arranged in a second,
different row, the second set of transducers being configured to
receive the wave transmitted along the pipe; and a controller
operatively connected to the second set of transducers for
receiving information about the wave received by the second set of
transducers, the controller being configured to analyze the
information about the wave received by the second set of
transducers to determine the presence of possible defects in the
pipe.
2. The ultrasonic sensor assembly as set forth in claim 1, wherein
the first set of transducers is configured to transmit the wave as
a guided wave.
3. The ultrasonic sensor assembly as set forth in claim 1, wherein
the first set of transducers is configured to transmit the wave as
a non-dispersive guided wave having a generally constant velocity
traveling through the pipe.
4. The ultrasonic sensor assembly as set forth in claim 1, wherein
the transducers arranged in the first row extend along a first
circumferential periphery of the pipe.
5. The ultrasonic sensor assembly as set forth in claim 4, wherein
the transducers arranged in the second row extend along a second
circumferential periphery of the pipe.
6. The ultrasonic sensor assembly as set forth in claim 1, wherein
the transducers arranged in the first row extend about a
circumference of the pipe.
7. The ultrasonic sensor assembly as set forth in claim 6, wherein
the transducers arranged in the second row extend about a
circumference of the pipe.
8. The ultrasonic sensor assembly as set forth in claim 1, wherein
the first set of transducers is configured to transmit multiple
waves along the pipe, the second set of transducers is configured
to receive the multiple waves transmitted along the pipe, and the
controller is configured to receive information about the multiple
waves received by the second set of transducers and to analyze the
information about the multiple waves received by the second set of
transducers.
9. The ultrasonic sensor assembly as set forth in claim 1, wherein
the pipe is configured to be at least one of linear, bent,
undulating and curved at least one of the first and second location
and has a cross-sectional shape, at least one of the first and
second sets of transducers is flexible to match the cross-sectional
shape at the respect first or second location.
10. The ultrasonic sensor assembly as set forth in claim 1, wherein
the pipe has first and second pipe ends, the first location is near
the first pipe end and the second location is near the second pipe
end, such that the first set of transducers is permanently attached
to the pipe near the first pipe end and the second set of
transducers is permanently attached to the pipe near the second
pipe end.
11. The ultrasonic sensor assembly as set forth in claim 1, wherein
the pipe has first and second pipe ends, at least one of the first
location is spaced a distance from the first pipe end and the
second location is spaced a distance from the second pipe end, such
that at least one of the first set of transducers is permanently
attached to the pipe spaced from the first pipe end and the second
set of transducers is permanently attached to the pipe spaced from
the second pipe end.
12. The ultrasonic sensor assembly as set forth in claim 1, wherein
at least one of the first and second sets of transducers includes
transducers that are permanently attached to the pipe at spaced
placements positioned substantially 360.degree. around the
pipe.
13. The ultrasonic sensor assembly as set forth in claim 1, wherein
the pipe has a longitudinal extent and the first set of transducers
is configured to transmit the wave to propagate longitudinally
along the pipe.
14. The ultrasonic sensor assembly as set forth in claim 1, wherein
the pipe has a longitudinal extent and the first set of transducers
is configured to transmit the wave to propagate torsionally
relative to the longitudinal extent.
15. The ultrasonic sensor assembly as set forth in claim 1, wherein
the pipe has a longitudinal extent and the first set of transducers
is configured to transmit the wave to propagate flexurally relative
to the longitudinal extent.
16. A method of providing an ultrasonic sensor assembly on a pipe,
the method comprising: providing a first set of transducers
configured to be attached to the pipe at a first location, the
first set of transducers being flexible and the first set of
transducers including at least transducers arranged in a first row;
wrapping the first set of transducers at least partially around the
pipe to match a shape of the pipe at the first location;
permanently attaching the first set of transducers to the pipe such
that the first set of transducers is configured to transmit a wave
along the pipe; providing a second set of transducers configured to
be attached to the pipe at a second, different location, the second
set of transducers being flexible and the second set of transducers
including at least transducers arranged in a second row; wrapping
the second set of transducers at least partially around the pipe to
match a shape of the pipe at the second location; permanently
attaching the second set of transducers to the pipe such that the
second set of transducers is configured to receive the wave
transmitted along the pipe; providing a controller; and operatively
connecting the controller to the second set of transducers for
receiving information about the wave received by the second set of
transducers, the controller being configured to analyze the
information about the wave received by the second set of
transducers to determine the presence of possible defects in the
pipe.
17. The method as set forth in claim 15, wherein the step of
providing the first set of transducers includes providing the first
set of transducers to be configured to transmit the wave as a
guided wave.
18. The method as set forth in claim 15, wherein the step of
providing the first set of transducers includes providing the first
set of transducers to be configured to transmit the wave as a
non-dispersive guided wave having a generally constant velocity
traveling through the pipe.
19. The method as set forth in claim 15, wherein the step of
providing the first set of transducers includes providing the first
set of transducers to be configured to transmit multiple waves
along the pipe.
20. The method as set forth in claim 15, wherein the pipe has a
longitudinal extent and the step of providing the first set of
transducers includes providing the first set of transducers to be
configured to transmit the wave to propagate longitudinally along
the pipe.
Description
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/956,423, filed Dec. 2, 2015, which in turn
is a continuation of U.S. patent application Ser. No. 13/747,522,
filed Jan. 23, 2013, now U.S. Pat. No. 9,228,888, and benefit of
priority is claimed from all of said applications and all of said
applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The present invention relates generally to ultrasonic sensor
assemblies, and more particularly, to aligning an ultrasonic sensor
assembly on a pipe.
[0004] Discussion of the Prior Art
[0005] Ultrasonic sensor assemblies are known and used in many
different applications. Ultrasonic sensor assemblies are used, for
example, to inspect a pipe and detect/identify at least one
characteristic of the pipe, such as corrosion, voids, inclusions,
length, thickness, etc. To accurately determine the location of
these characteristics of the pipe, a relative position of a first
transducer ring with respect to a second transducer ring should be
known. In the past, the first transducer ring would be precisely
longitudinally aligned with the second transducer ring, such that
circumferential locations of transmitters in the first transducer
ring would match circumferential locations of receivers in the
second transducer ring. Providing precise longitudinal alignment
could be difficult and time consuming. Further, alignment tools
(e.g., mechanical tools, optical/laser tools, software based tools,
etc.) were used to assist in longitudinal alignment.
[0006] Accordingly, it would be beneficial to provide an ultrasonic
sensor assembly that allows for the transducer rings to be
arbitrarily installed on the pipe. Further, it would be beneficial
to provide this arbitrary installation of the transducer rings
without the need for alignment tools.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The following presents a simplified summary of the invention
in order to provide a basic understanding of some example aspects
of the invention. This summary is not an extensive overview of the
invention. Moreover, this summary is not intended to identify
critical elements of the invention nor delineate the scope of the
invention. The sole purpose of the summary is to present some
concepts of the invention in simplified form as a prelude to the
more detailed description that is presented later.
[0008] In accordance with one aspect, an ultrasonic sensor assembly
for a pipe is provided. The ultrasonic sensor assembly includes a
first set of transducers configured to be attached to the pipe at a
first location. The first set of transducers is flexible and
configured to wrap at least partially around the pipe matching a
shape of the pipe at the first location. The first set of
transducers is permanently attached to the pipe. The first set of
transducers includes at least transducers arranged in a first row.
The first set of transducers is configured to transmit a wave along
the pipe. The ultrasonic sensor assembly includes a second set of
transducers configured to be attached to the pipe at a second,
different location. The second set of transducers is flexible and
configured to wrap at least partially around the pipe matching a
shape of the pipe at the second location. The second set of
transducers is permanently attached to the pipe. The second set of
transducers includes at least transducers arranged in a second,
different row. The second set of transducers is configured to
receive the wave transmitted along the pipe. The ultrasonic sensor
assembly includes a controller operatively connected to the second
set of transducers for receiving information about the wave
received by the second set of transducers. The controller is
configured to analyze the information about the wave received by
the second set of transducers to determine the presence of possible
defects in the pipe.
[0009] In accordance with another aspect, a method of providing an
ultrasonic sensor assembly on a pipe is provided. The method
includes providing a first set of transducers configured to be
attached to the pipe at a first location. The first set of
transducers is flexible and the first set of transducers includes
at least transducers arranged in a first row. The method includes
wrapping the first set of transducers at least partially around the
pipe to match a shape of the pipe at the first location. The method
includes permanently attaching the first set of transducers to the
pipe such that the first set of transducers is configured to
transmit a wave along the pipe. The method includes providing a
second set of transducers configured to be attached to the pipe at
a second, different location. The second set of transducers is
flexible and the second set of transducers includes at least
transducers arranged in a second row. The method includes wrapping
the second set of transducers at least partially around the pipe to
match a shape of the pipe at the second location. The method
includes permanently attaching the second set of transducers to the
pipe such that the second set of transducers is configured to
receive the wave transmitted along the pipe. The method includes
providing a controller. The method includes operatively connecting
the controller to the second set of transducers for receiving
information about the wave received by the second set of
transducers. The controller is configured to analyze the
information about the wave received by the second set of
transducers to determine the presence of possible defects in the
pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing and other aspects of the present invention
will become apparent to those skilled in the art to which the
present invention relates upon reading the following description
with reference to the accompanying drawings, in which:
[0011] FIG. 1 is a schematic, perspective view of an example
ultrasonic sensor assembly being used with a pipe in accordance
with an aspect of the present invention;
[0012] FIG. 2 is a schematic, perspective view of the example
ultrasonic sensor assembly similar to FIG. 1 with waves being
transmitted from a first transducer ring to a second transducer
ring;
[0013] FIG. 3 is an unwrapped planar view of the ultrasonic sensor
assembly and the pipe; and
[0014] FIG. 4 is an unwrapped planar view of the ultrasonic sensor
assembly similar to FIG. 3 during a process of determining a
relative position of the first transducer ring with respect to the
second transducer ring.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Example embodiment(s) that incorporate one or more aspects
of the present invention are described and illustrated in the
drawings. These illustrated examples are not intended to be a
limitation on the present invention. For example, one or more
aspects of the present invention can be utilized in other
embodiments and even other types of devices. Moreover, certain
terminology is used herein for convenience only and is not to be
taken as a limitation on the present invention. Still further, in
the drawings, the same reference numerals are employed for
designating the same elements.
[0016] FIG. 1 illustrates a perspective view of an example
ultrasonic sensor assembly 10 according to one aspect of the
invention. In short summary, the ultrasonic sensor assembly 10
includes a controller 20 in operative association with a first
transducer ring 30 and a second transducer ring 40. The first and
second transducer rings 30, 40 can transmit ultrasonic waves into a
pipe 12 for testing the pipe 12, including sensing and detecting a
characteristic (e.g., corrosion, thickness, voids, inclusions,
etc.) of the pipe 12. To provide improved sensing of the pipe 12, a
relative position of the first transducer ring 30 with respect to
the second transducer ring 40 is determined based on analyzing one
or more waves 50 (see FIG. 2, waves schematically represented as
arrowheads) received by the second transducer ring 40 from the
first transducer ring 30.
[0017] The pipe 12 is shown to include a tubular pipe having a
generally cylindrical shape extending between a first end 14 and an
opposing second end 16. The pipe 12 can include a non-solid body
(e.g., hollow body) or may be solid. It is to be appreciated that
the pipe 12 is somewhat generically/schematically depicted in FIGS.
1 and 2 for ease of illustration. Indeed, the pipe 12 is not
limited to the pipe extending along a linear axis, and may include
bends, undulations, curves, or the like. The pipe 12 has an outer
surface 18 forming a generally cylindrical shape. In further
examples, the pipe 12 includes other non-cylindrical shapes and
sizes. For example, the pipe 12 could have a non-circular
cross-sectional shape, such as by having a square or rectangular
cross-section. Still further, the pipe 12 may include a tubular
shape, conical shape, or the like. The pipe is not limited to
pipes, but instead, could include walls, planar or non-planar
surfaces, etc. The pipe 12 could be used in a number of
applications, including pipeline corrosion monitoring. As such, the
pipe 12 shown in FIG. 1 comprises only one possible example of the
pipe.
[0018] Turning to the controller 20, the controller is somewhat
generically/schematically depicted. In general, the controller 20
can include any number of different configurations. In one example,
the controller 20 is operatively attached to the first transducer
ring 30 and second transducer ring 40 by means of a wire 22. In
further examples, however, the controller 20 could be in wireless
communication with the first and second transducer rings 30, 40.
The controller 20 can send and receive information (e.g., data,
control instructions, etc.) from the first transducer ring 30
through the wire 22 (or wirelessly). This information can be
related to characteristics of the pipe 12 (e.g., corrosion, wall
thickness, voids, inclusions, etc.), characteristics of the waves
50 transmitted and/or received by the first and second transducer
rings 30, 40, or the like. The controller 20 can include circuits,
processors, running programs, memories, computers, power supplies,
ultrasound contents, or the like. In further examples, the
controller 20 includes a user interface, display, and/or other
devices for allowing a user to control the ultrasonic sensor
assembly 10.
[0019] Turning now to FIG. 2, the ultrasonic sensor assembly 10
includes the first transducer ring 30. The first transducer ring 30
can include a size and shape that substantially matches a size and
shape of the pipe 12. For example, the first transducer ring 30 can
be attached (e.g., temporarily or permanently) to the pipe 12, such
that the first transducer ring 30 wraps around the outer surface
18. In the shown example, the first transducer ring 30 has a
generally circular shape with a diameter that is slightly larger
than a diameter of the pipe 12. As such, the first transducer ring
30 is in contact with the outer surface 18. Of course, in further
examples, the first transducer ring 30 is not limited to having the
circular cross-sectional shape, and could include nearly any
cross-sectional size and shape that matches the cross-sectional
size and shape of the pipe 12. In another example, the first
transducer ring 30 is formed from a flexible material that can be
wrapped around the pipe 12.
[0020] The first transducer ring 30 is shown to be positioned near
the first end 14 of the pipe 12. In further examples, however, the
first transducer ring 30 is not so limited to such a position, and
could be arranged at nearly any location along the length of the
pipe 12. For example, the first transducer ring 30 could be closer
or farther from the first end 14, adjacent the second end 16, or
the like.
[0021] The first transducer ring 30 includes one or more
transmitters 32. The transmitters 32 are supported (e.g., fixed) to
the first transducer ring 30, such as being supported by a backing
material or the like. The transmitters 32 are somewhat
generically/schematically shown, as it is to be appreciated that
the transmitters 32 include nearly any size, shape, and
configuration. The transmitters 32 are provided to extend around
the first transducer ring 30 and in contact with the outer surface
18. The transmitters 32 can be positioned to extend substantially
360.degree. around the outer surface 18 of the pipe 12.
[0022] The first transducer ring 30 can be provided with any number
of transmitters 32. Further, the transmitters 32 can be arranged to
be closer together or farther apart than as shown. In the shown
example, the transmitters 32 include a first transmitter 32a, a
second transmitter 32b, a third transmitter 32c, and a fourth
transmitter 32d. While only these four transmitters are labeled in
FIG. 2, it is understood that the first transducer ring 30 is not
limited to including the four transmitters. The first transducer
ring 30 could likewise include a fifth transmitter, sixth
transmitter, etc. Indeed, other transmitters 32 are included within
the first transducer ring 30 but are obstructed from view.
[0023] Each of the transmitters 32 is capable of transmitting
(e.g., sending, conveying, etc.) one or more of the waves 50,
including a pulse, energy, and/or other impulses, along the pipe
12. It is to be appreciated that the waves 50 are somewhat
generically/schematically depicted as arrows for ease of
illustration. The waves 50 can propagate along an inspection region
34 through the pipe 12 from the first transducer ring 30. In one
example, the waves 50 propagate longitudinally along the pipe 12
(e.g., longitudinal guided wave mode). In other examples, the waves
50 include torsional (shear) and flexural modes in addition to the
longitudinal mode. The transmitters 32 can transmit a number of
different types of waves 50. In one possible example, the waves 50
are used to detect characteristics within the pipe 12 (e.g.,
corrosion, thickness, cracks, voids, inclusions, etc.). In another
example, the transmitters 32 each transmit non-dispersive guided
waves. As is generally known, non-dispersive guided waves have a
generally constant velocity traveling through a given medium (e.g.,
pipe 12 in the shown example) regardless of the presence or absence
of corrosion, thickness variations, cracks, or the like.
[0024] The ultrasonic sensor assembly 10 further includes the
second transducer ring 40 spaced apart from the first transducer
ring 30 along a length of the pipe 12. The second transducer ring
40 includes a size and shape that substantially matches a size and
shape of the pipe 12. For example, the second transducer ring 40 is
attached to the pipe 12 (e.g., temporarily or permanently), such
that the second transducer ring 40 wraps around the outer surface
18. In the shown example, the second transducer ring 40 has a
generally circular shape with a diameter that is slightly larger
than a diameter of the pipe 12. As such, the second transducer ring
40 is in contact with the outer surface 18. Of course, in further
examples, the second transducer ring 40 is not limited to having
the circular cross-sectional shape, and could include nearly any
cross-sectional size and shape that matches the cross-sectional
size and shape of the pipe 12.
[0025] The second transducer ring 40 is shown to be positioned near
the second end 16 of the pipe 12. In further examples, however, the
second transducer ring 40 is not so limited to such a position, and
could be arranged at nearly any location along the length of the
pipe 12. For example, the second transducer ring 40 could be closer
or farther from the second end 16, adjacent the first end 14, or
the like. Indeed, the positions of the first transducer ring 30 and
second transducer ring 40 could be switched, such that the first
transducer ring 30 is closer to the second end 16 while the second
transducer ring 40 is closer to the first end 14.
[0026] The second transducer ring 40 includes one or more receivers
42. The receivers 42 are supported (e.g., fixed) to the second
transducer ring 40, such as being supported by a backing material
or the like. The receivers 42 are somewhat
generically/schematically shown, as it is to be appreciated that
the receivers 42 include nearly any size, shape, and configuration.
The receivers 42 are provided to extend around the second
transducer ring 40 and in contact with the outer surface 18. The
receivers 42 can be positioned to extend substantially 360.degree.
around the outer surface 18 of the pipe 12.
[0027] The second transducer ring 40 can be provided with any
number of receivers 42. Further, the receivers 42 can be arranged
to be closer together or farther apart than as shown. In the shown
example, the receivers 42 include a first receiver 42a, a second
receiver 42b, a third receiver 42c, and a fourth receiver 42d.
While only these four receivers are labeled in FIG. 2, it is
understood that the second transducer ring 40 is not limited to
including the four receivers. Rather, the second transducer ring 40
could likewise include a fifth receiver, sixth receiver, etc.
[0028] Each of the receivers 42 is capable of receiving the waves
50 (e.g., pulse, energy, other impulses, etc.) from the
transmitters 32 of the first transducer ring 30. In one example,
the waves 50 received by the receivers 42 can be inspected, such as
with the controller 20, to detect the characteristics of the pipe
12. In particular, features of the waves 50 including a time of
flight, amplitude, or the like are analyzed to detect the
characteristics. To provide more accurate determination of these
characteristics, the waves 50 can first be analyzed to detect the
relative position of the first transducer ring 30 with respect to a
circumferential position of the second transducer ring 40.
[0029] Turning now to FIG. 3, the operation of determining the
relative position of the first transducer ring 30 with respect to a
circumferential position of the second transducer ring 40 will now
be described. In this example, an unwrapped planar view of the
ultrasonic sensor assembly 10 is shown for illustrative purposes
and to more clearly depict the locations of the transmitters
32a-32d with respect to the receivers 42a-42d. In particular, the
pipe 12, first transducer ring 30, and second transducer ring 40
are depicted as being two dimensionally planar in FIG. 3 for ease
of reference. Further, portions of the pipe 12 from the first end
14 to the first transducer ring 30 and from the second transducer
ring 40 to the second end 16 are also not shown so as to more
clearly depict the transmitters and receivers. However, in
operation, the ultrasonic sensor assembly 10 including the pipe 12
will more closely resemble the structure shown in FIGS. 1 and
2.
[0030] To determine the relative position of the first transducer
ring 30 and second transducer ring 40, the first transducer ring 30
will initially transmit the waves 50 along the pipe 12 towards the
second transducer ring 40. In particular, the waves 50 are
transmitted from one or more of the transmitters 32a-32d. In the
shown example, the waves 50 are transmitted from the third
transmitter 32c, however in operation, the waves 50 could similarly
be transmitted from the first transmitter 32a, second transmitter
32b, fourth transmitter 32d, and/or other not shown
transmitters.
[0031] The third transmitter 32c (or other transmitters) can
transmit a plurality of the waves 50, including a first wave 50a, a
second wave 50b, a third wave 50c, and a fourth wave 50d. Of
course, in further examples, any number of waves can be
transmitted, such as greater than or less than the four waves that
are shown. These waves 50a-50d can be transmitted simultaneously
(i.e., multiple waves transmitted at substantially the same time)
or sequentially (i.e., each wave successively transmitted after a
preceding wave). As such, the waves 50a-50d represent simultaneous
and/or sequential transmission. The waves 50a-50d will propagate
through the pipe 12 from the first transducer ring 30 towards the
second transducer ring 40.
[0032] The waves 50a-50d transmitted by the third transmitter 32c
include non-dispersive guided waves. As is generally known,
non-dispersive guided waves traveling through the pipe 12 have a
substantially constant velocity that is independent of changes in
wall thickness of the pipe 12. Likewise, defects in the pipe 12,
such as corrosion, voids, inclusions, etc., have a minimal or
negligible effect on the velocity of the non-dispersive guided
waves through the pipe 12. Accordingly, a time of flight of the
waves 50a-50d from the first transducer ring 30 to the second
transducer ring 40 depends primarily on the distance from the
transmitter (e.g., third transmitter 32c in the shown example) to
one of the receivers. The time of flight will therefore be
generally independent of changes in wall thickness or defects
(e.g., caused by corrosion, voids, inclusions, etc.).
[0033] The waves 50a-50d transmitted by the third transmitter 32c
are received by one or more of the receivers 42 of the second
transducer ring 40. In the shown example, the first receiver 42a
receives the first wave 50a, the second receiver 42b receives the
second wave 50b, the third receiver 42c receives the third wave
50c, and the fourth receiver 42d receives the fourth wave 50d.
Determining the relative position is of course not specifically
limited to including the four waves, and instead could include the
transmission of more or less waves than as shown. Likewise, the
waves 50a-50d are not limited to being transmitted from the third
transmitter 32c, and instead could be transmitted from one or more
of the first transmitter 32a, second transmitter 32b, fourth
transmitter 32d, or other, not shown transmitters. Further still,
the receivers 42a-42d are not limited to including the four
receivers, and could include a greater or smaller number of
receivers than as shown.
[0034] Turning now to FIG. 4, the operation of determining the
relative position of the first transducer ring 30 and second
transducer ring 40 will further be described. As shown, the
transmitters 32 of the first transducer ring 30 are longitudinally
misaligned from the receivers 42 of the second transducer ring 40.
By being longitudinally misaligned, the transmitters 32 are not
located at the same circumferential position as the receivers 42
along the outer surface 18 of the pipe 12. For example, the first
receiver 42a is offset (i.e., positioned lower in shown example)
than the first transmitter 32a. Likewise, each of the second
receiver 42b, third receiver 42c, and fourth receiver 42d are
offset (i.e., positioned lower) than the second transmitter 32b,
third transmitter 32c, and fourth transmitter 32d, respectively. Of
course, in further examples, the transmitters 32 could include a
larger or smaller offset from the receivers 42 than as shown.
[0035] To determine the relative position, an offset distance of
the receivers 42 with respect to a longitudinally aligned
positioned will be determined. The longitudinally aligned position
includes a location that is longitudinally aligned with one of the
transmitters (e.g. first to fourth transmitters 32a-32d) such that
an axis from one of the transmitters to the longitudinally aligned
position is parallel to a longitudinal axis of the pipe 12. For
example, FIG. 4 depicts four longitudinally aligned positions
(shown generically/schematically with x's): a first longitudinally
aligned position 142a, a second longitudinally aligned position
142b, a third longitudinally aligned position 142c, and a fourth
longitudinally aligned position 142d. Each of these longitudinally
aligned positions corresponds to (i.e., is longitudinally aligned
with) one of the transmitters. In particular, the first
longitudinally aligned position 142a is longitudinally aligned with
the first transmitter 32a. The second longitudinally aligned
position 142b is longitudinally aligned with the second transmitter
32b. The third longitudinally aligned position 142c is
longitudinally aligned with the third transmitter 32c. The fourth
longitudinally aligned position 142d is longitudinally aligned with
the fourth transmitter 32d. Accordingly, a line from the first
transmitter 32a to the first longitudinally aligned position 142a
will be parallel to the longitudinal axis of the pipe 12. Likewise,
a line from each of the second, third, and fourth transmitters
32b-32d to the second, third, and fourth longitudinally aligned
positions 142b-142d, respectively, will also be parallel to the
longitudinal axis of the pipe 12.
[0036] Next, an offset distance, represented as .DELTA.d, between
each of the longitudinally aligned positions 142a-142d and each of
the receivers 42a-42d will be determined. A separation distance,
represented as d, is defined as a distance separating each of the
receivers 42a-42d. For example, the first receiver 42a is separated
from the second receiver 42b by the separation distance d.
Likewise, the same separation distance d separates the second
receiver 42b from the third receiver 42c, and the third receiver
42c from the fourth receiver 42d. This separation distance d can be
readily obtained in any number of ways, such as by measurement,
obtaining from a manufacturer of the second transducer ring 40,
etc. In one example, this separation distance d can be the same for
the receivers 42 in the second transducer ring 40 as with the
transmitters 32 in the first transducer ring 30.
[0037] To determine the offset distance .DELTA.d, a distance from
each of the transmitters 32a-32d to the receivers 42a-42d will
first be determined. In the shown example, the distance from the
third transmitter 32c to each of the receivers 42a-42d is
determined by analyzing characteristics of the waves 50a-50d,
including time of flight, amplitude, etc. Since the waves 50a-50d
include the non-dispersive guided waves that are generally
independent of wall thickness, the time of flight for waves 50a-50d
traveling a longer distance will be longer as compared to a time of
flight for a shorter distance. Further, the velocity of the waves
50a-50d is generally known and constant through the pipe 12. As
such, the time of flight of the waves 50a-50d can be measured, such
as by the controller 20, for each of the receivers 42a-42d. In
particular, the time of flight for the first wave 50a from the
third transmitter 32c to the first receiver 42a is measured.
Likewise, the time of flight for each of the second wave 50b, third
wave 50c, and fourth wave 50d will be measured from the third
transmitter 32c to the second receiver 42b, third receiver 42c, and
fourth receiver 42d, respectively.
[0038] The time of flight of each of the waves 50a-50d can then be
used to calculate the distance between the third transmitter 32c
and each of the receivers 42a-42d. The velocity for each of the
waves 50a-50d is known (and is generally the same). Accordingly,
the time of flight (e.g., seconds, milliseconds, etc.) for each of
the waves 50a-50d multiplied by the velocity (e.g.,
distance/seconds or milliseconds) will yield the distance from the
third transmitter 32c to each of the receivers 42a-42d. This
distance can be represented in the formula below as 32c, 42. For
example, a distance from the third transmitter 32c to the first
receiver 42a is represented as (32c, 42a). Likewise, distances from
the third transmitter 32c to the second receiver 42b, third
receiver 42c, and fourth receiver 42d are represented as (32c,
42b), (32c, 42c), and (32c, 42d), respectively.
[0039] With the separation distance d and distances between the
third transmitter 32c and each of the receivers 42a-42d now known,
the relative position of the transmitters 32a-32d with respect to
the receivers 42a-42d can now be calculated. Initially, a distance
from the third transmitter 32c to the third longitudinally aligned
position 142c is shown below. This distance also corresponds to a
length of the inspection region 34:
32c,142C=L (1)
[0040] A formula representing the distance from the third
transmitter 32c to the third receiver 42c is shown below (as
32c,42c) and is based on the Pythagorean Theorem. Here, .DELTA.d
represents the offset distance between the third longitudinally
aligned position 142c and the third receiver 42c while L represents
the longitudinal distance from the third transmitter 32c to the
third longitudinally aligned position 142c:
32c,42c= {square root over (.DELTA.d.sup.2+L.sup.2)} (2)
[0041] Next, a formula representing the distance from the third
transmitter 32c to the fourth receiver 42d is shown below, wherein
(d+.DELTA.d) represents the offset distance between the third
longitudinally aligned position 142c and the fourth receiver 42d. L
again represents the longitudinal distance from the third
transmitter 32c to the third longitudinally aligned position
142c:
32c,42d= {square root over ((d+.DELTA.d).sup.2+L.sup.2)} (3)
[0042] A formula representing the distance from the third
transmitter 32c to the second receiver 42b is shown below, wherein
(d-.DELTA.d) represents the offset distance between the third
longitudinally aligned position 142c and the second receiver 42b. L
again represents the longitudinal distance from the third
transmitter 32c to the third longitudinally aligned position
142c:
32c,42b= {square root over ((d-.DELTA.d).sup.2+L.sup.2)} (4)
[0043] Using formulas (3) and (4), the offset distance .DELTA.d can
be determined:
.DELTA. d = ( 32 c , 42 d ) 2 - ( 32 c , 42 b ) 2 4 d ( 5 )
##EQU00001##
[0044] Next, the longitudinal distance L between the first
transducer ring 30 and the second transducer ring 40 can also be
determined:
L = ( 32 c , 42 c ) 2 - .DELTA. d 2 ( 6 ) L = ( 32 c , 42 c ) 2 - (
( 32 c , 42 d ) 2 - ( 32 c , 42 b ) 2 4 d ) 2 ( 7 )
##EQU00002##
[0045] Accordingly, by initially knowing the separation distance d
between each of the receivers 42a-42d and the time of flight of
each of the waves 50a-50d, the offset distance .DELTA.d of the
receivers 42a-42d from the longitudinally aligned positions
142a-142d is determinable. Likewise, the longitudinal distance
between the first transducer ring 30 and second transducer ring 40,
designated as longitudinal distance L, can similarly be
calculated.
[0046] It is to be appreciated that shown examples and the
aforementioned formulas include the waves 50a-50d propagating only
from the third transmitter 32c. However, the method of determining
the relative position of the first transducer ring 30 with respect
to a circumferential position of the second transducer ring 40 is
not so limited. Rather, in further examples, any of the
transmitters 32 (e.g., first transmitter 32a, second transmitter
32b, fourth transmitter 32d, etc.) could be used instead of the
third transmitter 32c. Similarly, the offset distance .DELTA.d and
longitudinal distance L could be calculated by using greater than
or less than the four waves 50. Further still, the formulas are not
limited to using the second receiver 42b, third receiver 42c, and
fourth receiver 42d. Instead, the formulas are still effective when
using the first receiver 42a, some or all of the second, third, and
fourth receivers 42b-42d, and/or other, not shown receivers.
[0047] By calculating the relative position of the first transducer
ring 30 with respect to a circumferential position of the second
transducer ring 40, precise alignment of the transducer rings is no
longer needed. Further, alignment tools (e.g., mechanical tools,
optical/laser alignment tools, software tools, etc.) may no longer
be needed to precisely align the transducer rings. Instead, the
first transducer ring 30 and second transducer ring 40 could be
attached to the pipe 12. Once attached, the aforementioned method
can quickly and accurately determine the relative positions of the
transducer rings. The first transducer ring 30 and second
transducer ring 40 can then be used to accurately determine
locations of characteristics (e.g., corrosion, thickness, voids,
inclusions, etc.) within the pipe 12.
[0048] In a second example, the relative position of the first
transducer ring 30 with respect to the circumferential position of
the second transducer ring 40 is determinable with a parameter
optimization process. Within the parameter optimization process,
one or more of the waves 50 are initially transmitted by the
transmitters 32. As described above, the waves 50 include
non-dispersive guided waves that have a generally constant velocity
traveling through the pipe 12. The velocity of the waves 50 is
largely independent of pipe thickness variations, presence/absence
of corrosion, cracks, etc. In one possible example, the
non-dispersive guided waves have a low frequency such that the
sensitivity of the velocity of the waves 50 with respect to pipe
thickness changes is negligible.
[0049] The waves 50 transmitted from the transmitters 32 of the
first transducer ring 30 are received by the receivers 42 at the
second transducer ring 40. As described above, the characteristics
of the waves 50 are inspected, such as with the controller 20, to
detect the relative position of the first transducer ring 30 to the
second transducer ring 40. For example, the characteristics of the
waves 50 include the time of flight between transmitters 32 of the
first transducer ring 30 and the receivers 42 of the second
transducer ring 40. The time of flight for the waves 50 will be
measured for some or all of the combinations of transmitters 32 and
receivers 42. For instance, a separate time of flight between the
first transmitter 32a and each of the receivers 42 (e.g., first
receiver 42a, second receiver 42b, third receiver 42c, fourth
receiver 42d, etc.) is measured. Likewise, times of flights for the
second transmitter 32b, third transmitter 32c, fourth transmitter
32d and each of the receivers may also be measured.
[0050] Next, with these measured times of flights, a model will be
created that approximates the relative position of the first
transducer ring 30 with respect to a position (e.g.,
circumferential, axial, etc.) of the second transducer ring 40. The
model can be in the form of an equation, formula, or the like, and
can incorporate a number of variables in approximating the relative
positions of the first transducer ring 30 and second transducer
ring 40. Variables can include, for example, time of flight between
individual transmitters and receivers, the pipe diameter, nominal
pipe wall thickness, spacing between the first transducer ring 30
and second transducer ring 40, etc.
[0051] Within this model, an estimated location of the first
transducer ring 30 and second transducer ring 40 is determined.
This estimated location can be in the form of an XY position of the
individual transmitters 32 and receivers 42, the relative location
of the transmitters 32 to the receivers 42, or the like. Further,
the model may include multiple equations, formulas, etc., such as
by having an equation/formula for each combination of transmitters
32 and receivers 42. This equation/formula includes, as a variable,
an estimated time of flight between each particular combination of
transmitter 32 and receiver 42.
[0052] Next, parameter optimization is used to optimize the
locations of the first transducer ring 30 with respect to the
second transducer ring 40 within the model. In particular, the
measured time of flights for each of the waves 50 will be compared
to the estimated time of flights generated within the model. For
example, the model may generate an estimated time of flight of 150
microseconds between one particular combination of transmitter 32
and receiver 42. In comparison, the measured value of the time of
flight between this combination of transmitter 32 and receiver 42
may have been 151 microseconds. As such, an error of 1 microsecond
is determined for this particular transmitter/receiver combination.
A similar comparison can then be made for each combination of
transmitter 32 and receiver 42 (e.g., difference between measured
time of flight and model/estimated time of flight).
[0053] Next, a sum of square errors is used to calculate the
difference between the model and measured values. This sum of
square errors is used to determine how closely the model
approximates the actual positions of transmitters 32 with respect
to the receivers 42. For instance, each of the errors (e.g.,
difference between measured time of flight and model/estimated time
of flight) for each combination of transmitters 32 and receivers 42
is determined. These errors are then each squared (i.e.,
multiplying each error by itself) and added together. This
summation will generate a figure of merit that indicates how
closely the model matches the measurement with respect to the
relative positions of the first transducer ring 30 and second
transducer ring 40. A lower figure of merit indicates that the
model more closely matches the measurements (e.g., measured time of
flight) than a higher figure of merit.
[0054] By using the parameter optimization process, a relatively
accurate determination of the relative positions of the first
transducer ring 30 with respect to a position (e.g.,
circumferential, axial, etc.) position of the second transducer
ring 40 is determinable. In particular, a position of the first
transducer ring 30 with respect to the second transducer ring 40 is
calculated by comparing measured values (e.g., time of flight
between transmitters and receivers) with a model of predicted
values.
[0055] The invention has been described with reference to the
example embodiments described above. Modifications and alterations
will occur to others upon a reading and understanding of this
specification. Example embodiments incorporating one or more
aspects of the invention are intended to include all such
modifications and alterations insofar as they come within the scope
of the appended claims.
* * * * *