Note: Descriptions are shown in the official language in which they were submitted.
TITLE
Method for Detecting Defect of Pipe, Device for Detecting Defect of Pipe,
Apparatus for Detecting Defect of Pipe
BACKGROUND OF THE PRESENT INVENTION
FIELD OF INVENTION
[0001] The present invention relates to a field of detection technique, and in
particular
to a method for detecting a defect of a pipe, a device for detecting the
defect of the pipe
and an apparatus for detecting the defect of the pipe.
DESCRIPTION OF RELATED ARTS
[0002] With advances in science and technology and requirements in industrial
production, a range of usage of a transporting pipe becomes increasingly
broad. A long
distance transporting pipe is a main transporting manner of a production in an
industry of
petroleum natural gas. And, if the long distance transporting pipe for the
petroleum
natural gas has a malfunction such as a leakage or the like, it causes
pollution in addition
to losses of shutdown and salvage. Therefore, how to ensure a safe operation
of the
existing long distance transporting pipe and new pipe for the petroleum
natural gas to
reduce a probability of a security accident and implement a intrinsic safety
of the
operation of the pipe is an urgent affair of ensuring the safe operation of
the pipe.
[0003] Since the long distance transporting pipe for the petroleum natural gas
is buried
.. underground generally, a main working flow of detecting a defect of such
buried pipe are
still the following steps: excavating, stripping an antisepsis (incubation)
layer, detecting,
enclosing and backfilling. It is obvious that this is a destructive detecting
method, and a
representativeness of data detected and a reliability of an evaluating
conclusion are
affected by numbers of points excavated (sampled) and a distribution range
thereof.
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Therefore, how to detect the buried pipe without excavating and stopping
transporting is
a problem that deserves an in-depth exploration.
[0004] There are many conventional methods of nondestructive detecting
including a
method of ultrasonic detection, a method of vortices detection and a method of
ray
detection. The ultrasonic detection is implemented by using information
provided by an
interaction between an ultrasonic wave and an object, and the ultrasonic wave
can
propagate in a metal. an deficiency of such method is that an attenuation of
the ultrasonic
wave in the air is fast, and there needs a propagation medium of the
ultrasonic wave,
which may be a coupling agent such as oil or water generally at the time of
detection, so
it is not appropriate for detection of the buried pipe.
[0005] The method of ray detection is a method of nondestructive detecting by
using a
physical effect (for example, a variation of intensity of radiation,
scattering or the like)
generated by an interaction between ionizing radiation and a subject to detect
a
discontinuity, a structure or a thickness or the like in a work piece. It is
also not
appropriate for the detection of the buried pipe.
[0006] The method of vortices detection operates according to a principle of
electromagnetic induction, so the method of vortices detection can detect a
surface defect
and a near surface defect of the work piece. A notable feature of the method
of vortices
detection is functioning to electrically conductive material rather than
ferromagnetic
material, but an effect of the ferromagnetic material is not good. Secondly, a
fineness, a
smoothness, a border or the like of the surface of the work piece to be
detected has large
influence to the vortices, thus, the method of vortices detection is usually
used to the
detection of non-ferromagnetic work piece such as a copper tube or the like
which has
relatively regular shape and relatively clean surface. If the buried pipe is a
ferromagnetic
pipe, the method of vortices detection can't be used. And, the method of
vortices
detection also needs an exciting source, and it still needs excavating to
detect the buried
pipe.
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[0007] A Chinese patent CN102095080A disclosed a method for detecting the
buried
pipe using a magnetic method without excavating, and its principle is using
magnetism
that the buried pipe magnetized by an earth magnetic field itself has as the
exciting
source and using a flux gate sensor having 1nT of a resolution of magnetic
induction
intensity to detect the magnetic induction intensity and attenuation amount
above a lower
side, and continuing detection results downward at thc same time, and
detecting a quality
of the pipe by data processing. However, it does not disclose how to detect
the defect of
the buried pipe specifically in the disclosure, thus, it can't determine a
position of the
defect and a magnitude of the defect of the buried pipe.
SUMMARY OF THE PRESENT INVENTION
[0008] Technical problem to be solved by the present invention is to overcome
the
conventional deficiencies, and technical object of the present invention is to
provide a
method for detecting a defect of a pipe, a device for detecting the defect of
the pipe and
an apparatus for detecting the defect of the pipe which can detect a position
of the defect
and a magnitude of the defect in the pipe accurately.
[0009] In order to solve the above technical problem, one aspect of the
present
invention provides the method for detecting the defect of the pipe comprising
the steps
executed by a computer of: detecting a first parameter related to a magnetic
induction
intensity along a length direction of the pipe; determining whether the first
parameter
exceeds a predetermined threshold; determining a position at which the first
parameter
exceeds the predetermined threshold as the position of the defect of the pipe;
and
determining a degree of the defect of the pipe based on a numerical value of
the first
parameter exceeding the predetermined threshold.
[0010] In the above-described method for detecting the defect of the pipe, the
first
parameter is a rate of change in a second direction of a component of the
magnetic
induction intensity in a first direction in a three-dimensional system of
coordinate.
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[0011] In the above-described method for detecting the defect of the pipe, the
first
direction is same as the second direction, or the first direction is different
from the second
direction.
[0012] In the above-described method for detecting the defect of the pipe, the
method
further comprises the steps of determining the degree of the defect of the
pipe based on
the numerical value of the first parameter exceeding the predetermined
threshold
specifically includes: determining the magnitude of the defect of the pipe
based on an
magnitude of the first parameter exceeding the predetermined threshold; and/or
determining a length of the defect of the pipe based on a length in which the
first
.. parameter exceeds the predetermined threshold continuously.
[0013] In the above-described method for detecting the defect of the pipe, the
method
further comprises a step of drawing a graphical chart of the magnitude of the
first
parameter versus a distance of the pipe in the length direction.
[0014] In the above-described method for detecting the defect of the pipe, the
method
further comprises the steps of detecting a second parameter related to the
magnetic
induction intensity along the length direction of the pipe; determining
whether the second
parameter exceeds the predetermined threshold; determining a position at which
the
second parameter exceeds the predetermined threshold as the position of the
defect of the
pipe; and determining the degree of the defect of the pipe based on the
numerical value of
.. the second parameter exceeding the predetermined threshold.
[0015] In the above-described method for detecting the defect of the pipe,
when the
position at which the first parameter exceeds the predetermined threshold is
same as the
position at which the second parameter exceeds the predetermined threshold,
the degree
of the defect of the pipe is determined based on the numerical value of the
first parameter
exceeding the predetermined threshold and the numerical value of the second
parameter
exceeding the predetermined threshold.
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[0016] In the above-described method for detecting the defect of the pipe, the
second
parameter is a rate of change in a fourth direction of a component of the
magnetic
induction intensity in a third direction in the three-dimensional system of
coordinate.
[0017] In the above-described method for detecting the defect of the pipe, the
third
direction is same as the fourth direction, or the third direction is different
from the fourth
direction.
[0018] In the above-described method for detecting the defect of the pipe, the
first
direction, the second direction, the third direction and the fourth direction
are one of a x
direction, a y direction and a z direction in the three-dimensional system of
coordinate.
[0019] In the above-described method for detecting the defect of the pipe, the
step of
determining whether the first parameter exceeds the predetermined threshold
specifically
comprises the steps of: executing a differential processing on the first
parameter; adding a
variance of n times to/subtracting the variance of n times from an average
value of the
magnitude of the first parameter after the differential processing as the
predetermined
threshold, wherein n 3; and determining whether the first parameter exceeds
the
predetermined threshold.
[0020] In the above-described method for detecting the defect of the pipe, the
step of
determining whether the first parameter exceeds the predetermined threshold
further
comprises the steps of: in case that there is no pipe to be detected,
detecting a third
parameter related to the magnetic induction intensity along the length
direction of the
pipe, wherein the third parameter is a parameter which is same as the first
parameter; and
in the case that the first parameter is larger than the third parameter,
optimizing the first
parameter with the third parameter, and determining whether the optimized
first
parameter exceeds the predetermined threshold.
[0021] In the above-described method for detecting the defect of the pipe, the
method
further comprises the step of in addition to the first parameter and the
second parameter
related to the magnetic induction intensity, further detecting rates of change
in three
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directions x, y and z in the coordinate system of three components Hx, Hy and
Hz of
the magnetic induction intensity in three reference directions in the three-
dimensional
system of coordinate along the length direction of the pipe respectively, to
constitute a
magnetic gradient matrix G including 9 elements in total:
al-lx I ax aHx I ay al-lx I az
g g X)/ g
G =aH / ax aHy / ay aHy / az = gyx gw
[0022] aH I ax aHz I ay aHz I az
_ z - -gzx gzy gzz
[0023] Another aspect of the present invention provides the device for
detecting the
defect of the pipe comprising: a computer executing the following module: a
detecting
unit configured to detect a first parameter related to a magnetic induction
intensity along
a length direction of the pipe, a deciding unit configured to determine
whether the first
parameter exceeds a predetermined threshold; and a control unit configured to
determine
a position at which the first parameter exceeds the predetermined threshold as
a position
of the defect of the pipe, and determining a degree of the defect of the pipe
based on a
numerical value of the first parameter exceeding the predetermined threshold.
[0024] In the above-described device for detecting the defect of the pipe, the
first
parameter is a rate of change in a second direction of a component of the
magnetic
induction intensity in a first direction in a three-dimensional system of
coordinate.
[0025] In the above-described device for detecting the defect of the pipe, the
first
direction is same as the second direction, or the first direction is different
from the second
direction.
[0026] In the above-described device for detecting the defect of the pipe, the
control
unit further comprises: a magnitude of defect determining module configured to
determine the magnitude of the defect of the pipe based on a magnitude of the
first
parameter exceeding the predetermined threshold: and/or a length of defect
determining
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module configured to determine a length of the defect of the pipe based on a
length in
which the first parameter exceeds the predetermined threshold continuously.
[0027] In the above-described device for detecting the defect of the pipe, the
device
further comprises a drawing unit configured to draw a graphical chart of the
magnitude of
the first parameter versus a distance in the length direction of the pipe
based on the first
parameter detected by the detecting unit.
[0028] In the above-described device for detecting the defect of the pipe, the
detecting
unit is further configured to detect a second parameter related to the
magnetic induction
intensity along the length direction of the pipe; the deciding unit is further
configured to
determine whether the second parameter exceeds the predetermined threshold;
and the
control unit is further configured to determine a position at which the second
parameter
exceeds the predetermined threshold as the position of the defect of the pipe,
and
determine the degree of the defect of the pipe based on a numerical value of
the second
parameter exceeding the predetermined threshold.
.. [0029] In the above-described device for detecting the defect of the pipe,
when the
position at which the first parameter exceeds the predetermined threshold is
same as the
position at which the second parameter exceeds the predetermined threshold,
the control
unit determines the magnitude of the defect of the pipe based on the numerical
value of
the first parameter exceeding the predetermined threshold and the numerical
value of the
second parameter exceeding the predetermined threshold.
[0030] In the above-described device for detecting the defect of the pipe, the
second
parameter is a rate of change in a fourth direction of a component of the
magnetic
induction intensity in a third direction in the three-dimensional system of
coordinate.
[0031] In the above-described device for detecting the defect of the pipe, the
third
direction is same as the fourth direction, or the third direction is different
from the fourth
direction.
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[0032] In the above-described device for detecting the defect of the pipe, the
first
direction, the second direction, the third direction and the fourth direction
are one of a x
direction, a y direction and a z direction in the three-dimensional system of
coordinate.
[0033] In the above-described device for detecting the defect of the pipe, the
deciding
unit further comprises: a differential processing module configured to execute
a
differential processing on the first parameter; a arithmetic processing module
configured
to add a variance of n times to/subtract the variance of n times from an
average value of
the first parameter after the differential processing of the differential
processing module
as the predetermined threshold, wherein I n 3; and a deciding module
configured to
determine whether the first parameter exceeds the predetermined threshold.
[0034] In the above-described device for detecting the defect of the pipe, the
detecting
unit is further configured to detect a third parameter related to the magnetic
induction
intensity along the length direction of the pipe in case that there is no pipe
to be detected,
wherein the third parameter is a parameter which is same as the first
parameter; and the
deciding unit is further configured to optimize the first parameter with the
third parameter
in case that the first parameter is larger than the third parameter, and
determine whether
the optimized first parameter exceeds the predetermined threshold.
[0035] In the above-described device for detecting the defect of the pipe, the
detecting
unit is further configured to, in addition to the first parameter and the
second parameter
related to the magnetic induction intensity, further detect rates of change in
three
directions x, y and z in the coordinate system of three components Hz, H, and
Hz of
the magnetic induction intensity in three reference directions in the three-
dimensional
system of coordinate along the length direction of the pipe respectively, to
constitute a
magnetic gradient matrix G including 9 elements in total:
aHx I ax 01-1, I ay aHx I Oz g. gxy gxz
G = aH I ax afri I ay aH 1 Oz = g g g
Yx W Yz
[0036] OH I ax OH, I ay aH, I Oz
gzx gzy gzz
= 8
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[0037] In the above-described device for detecting the defect of the pipe, the
detecting
unit specifically comprises: a first three-components magnetic measuring
sensor, a
second three-components magnetic measuring sensor arranged symmetrically with
a
center of the detecting unit to the first three-components magnetic measuring
sensor, a
third three-components magnetic measuring sensor and a fourth three-components
magnetic measuring sensor arranged symmetrically with a center of the
detecting unit to
the third three-components magnetic measuring sensor, wherein the first, the
second, the
third and the fourth three-components magnetic measuring sensors are cross-
arranged in
a plane; and each magnetic measuring sensor in the first, the second, the
third and the
fourth three-components magnetic measuring sensors calculate a magnetic
gradient of a
central position of the cross by detecting values of magnetic induction
intensity in three
reference directions in the three-dimensional system of coordinate thereof, so
as to
measure the magnetic gradient matrix G at the central position of the cross:
aH
/ ax aHõ / ay aFfx / Oz
gxx gxy gX2
G = aH / ax aH / ay aH / Oz = g
gYY gyz
aH / ax aH, / ay aH, / az
gzx gzy
_ _
Blx ¨Blx Blv ¨ B3v B2x ¨ BOx
Ax Ax Az
B1, (Blx ¨B3x B2z -BOz Bõ ¨ Bõ,
Ax Ax Az Az
131, ¨ B3, B2y ¨ B0 B2z ¨ BOz
[0038] = - Ax Az Az _
[0039] wherein, Ax is a distance between the first three-components magnetic
measuring sensor and the second three-components magnetic measuring sensor, Az
is a
distance between the third three-components magnetic measuring sensor and the
fourth
three-components magnetic measuring sensor, 131x is a component of the
magnetic
induction intensity in the x direction measured by the first three-components
magnetic
measuring sensor, B1, is a component of the magnetic induction intensity in
the y
direction measured by the first three-components magnetic measuring sensor,
131, is a
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component of the magnetic induction intensity in the z direction measured by
the first
three-components magnetic measuring sensor; B2, is a component of the magnetic
induction intensity in the x direction measured by the second three-components
magnetic measuring sensor, B2y is a component of the magnetic induction
intensity in
the y direction measured by the second three-components magnetic measuring
sensor,
B2, is a component of the magnetic induction intensity in the z direction
measured by
the second three-components magnetic measuring sensor; Bõ, is a component of
the
magnetic induction intensity in the x direction measured by the third three-
components
magnetic measuring sensor, B0y is a component of the magnetic induction
intensity in
the y direction measured by the third three-components magnetic measuring
sensor, Bõ,
is a component of the magnetic induction intensity in the z direction measured
by the
third three-components magnetic measuring sensor; Bõ is a component of the
magnetic
induction intensity in the x direction measured by the fourth three-components
magnetic
measuring sensor, B3y a component of the magnetic induction intensity in the y
direction measured by the fourth three-components magnetic measuring sensor,
Bõ is a
component of the magnetic induction intensity in the z direction measured by
the fourth
three-components magnetic measuring sensor.
[0040] Still another aspect of the present invention provides an apparatus for
detecting
the defect of the pipe including: a shelf provided above a pipe to be
detected; a sliding
track provided on the shelf and being able to slide along a length direction
of the shelf;
the device for detecting the defect of the pipe as described previously
slidably connected
to the sliding track through a slipper to detect the defect of the pipe of the
pipe to be
detected.
[0041] In the above-described apparatus for detecting the defect of the pipe,
an
actuating device for making the device for detecting the defect of the pipe to
slide in
uniform speed on the sliding track is provided.
CA 2952294 2018-04-11
[0042] In the above-described apparatus for detecting the defect of the pipe,
the
actuating device adopts any one of actuating manners including man-power, air
pressure
and hydraulic pressure.
[0043] With the method for detecting the defect of the pipe, the device for
detecting the
defect of the pipe and the apparatus for detecting the defect of the pipe of
the present
invention, whether there is the defect in the pipe can be decided based on
parameters
related to the magnetic induction intensity, and the position of the defect of
the pipe can
be determined according to a position at which the parameters are abnormal,
and the
degree of the defect of the pipe can be determined according to numerical
values of the
parameters which are abnormal. Accordingly, the position of the defect and the
degree of
the defect in the pipe can be detected accurately.
[0044] Still further objects and advantages will become apparent from a
consideration
of the ensuing description and drawings.
[0045] These and other objectives, features, and advantages of the present
invention
will become apparent from the following detailed description, the accompanying
drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Figure 1 is a schematic flow chart illustrating a method for detecting
a defect of
a pipe according to a first embodiment of present invention;
[0047] Figure 2 is a schematic diagram of a graphical chart drawn by detecting
5
elements of a magnetic gradient matrix;
[0048] Figure 3 is a schematic diagram of a curve obtained by executing a
differential
processing on one curve in Figure 2;
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[0049] Figure 4 is a schematic diagram of abnormal areas presented after
processing of
curves shown in Figure 2;
[0050] Figure 5 is a schematic diagram after integrating the abnormal areas
presented
after processing as shown in Figure 4;
5 .. [0051] Figure 6 is a schematic diagram of the defect of the pipe made
based on the
abnormal areas integrated as shown in Figure 5;
[0052] Figure 7 is a schematic block diagram illustrating a device for
detecting the
defect of the pipe according to a second embodiment of the present invention;
[0053] Figure 8 is a schematic diagram of a magnetic gradient detecting
component
.. according to the embodiments of the present invention; and
[0054] Figure 9 is a schematic diagram illustrating an apparatus for detecting
the defect
of the pipe according to a third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0055] The following description is disclosed to enable any person skilled in
the art to
.. make and use the present invention. Preferred embodiments are provided in
the
following description only as examples and modifications will be apparent to
those
skilled in the art. The general principles defined in the following
description would be
applied to other embodiments, alternatives, modifications, equivalents, and
applications
without departing from the spirit and scope of the present invention.
[0056] According to a first embodiment of present invention, a method for
detecting a
defect of a pipe comprises the steps of: detecting a first parameter related
to a magnetic
induction intensity along a length direction of the pipe; determining whether
the first
parameter exceeds a predetermined threshold; determining a position at which
the first
12
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parameter exceeds the predetermined threshold as a position of the defect of
the pipe; and
determining a degree of the defect of the pipe based on a numerical value of
the first
parameter exceeding the predetermined threshold.
[0057] With the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, whether there is the defect in the pipe
can be
decided based on the first parameter related to the magnetic induction
intensity, and
further, the position of the defect of the pipe can be determined according to
the position
at which the parameter exceeds the predetermined threshold, and the degree of
the defect
of the pipe can be determined according to the numerical value of the first
parameter
exceeding the predetermined threshold. Thus, the method for detecting the
defect of the
pipe of the present invention can detect the defect in the pipe accurately,
and determine
the position of the defect and the degree of the defect accurately.
[0058] Figure 1 is a schematic flow chart illustrating the method for
detecting the
defect of the pipe according to the first embodiment of present invention. As
shown in
Figure 1, the method for detecting the defect of the pipe according to the
first
embodiment of the present invention comprises the step executed by a computer
of: Si,
detecting the first parameter related to the magnetic induction intensity
along the length
direction of the pipe; S2, determining whether the first parameter exceeds the
predetermined threshold; S3, determining the position at which the first
parameter
exceeds the predetermined threshold as the position of the defect of the pipe;
and S4,
determining the degree of the defect of the pipe based on the numerical value
of the first
parameter exceeding the predetermined threshold.
[0059] Here, those skilled in the art can understand that, the first parameter
can be
detected continuously at respective points in the length direction of the
pipe, or the first
parameter can be detected discretely selectively at a plurality of points in
the length
direction of the pipe at the time of detecting the first parameter in the
length direction of
the pipe. That is, whether there is the defect at the detected position can be
determined by
detecting at a certain one or more points in the pipe.
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[0060] In particular, the method for detecting the defect of the pipe
according to the
first embodiment of the present invention comprises the steps of: detecting
the first
parameter related to the magnetic induction intensity at a first point in the
pipe;
determining whether the first parameter exceeds the predetermined threshold;
if the first
parameter exceeds the predetermined threshold, determining the first point as
the position
of the defect in the pipe, and determining the degree of the defect at the
first point based
on the numerical value of the first parameter exceeding the predetermined
threshold.
[0061] However, those skilled in the art can understand that, in order to
ensure
accuracy and fullness of the detection, the embodiments of the present
invention
preferably adopt a manner of a continuous detection. Also, those skilled in
the art can
understand that, the following description can be equally applied to a
continuous
detection and a discrete detection of the defect of the pipe, and the
embodiments of the
present invention do not intend to make any restriction thereto.
[0062] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, the first parameter is a rate of change
in a second
direction of a component of the magnetic induction intensity in a first
direction in a three-
dimensional system of coordinate. Preferably, the first parameter is a rate of
change in a
second reference direction of a component of the magnetic induction intensity
in a first
reference direction in the three-dimensional system of coordinate. And, in the
three-
dimensional system of coordinate, the first direction may be same as the
second direction,
or may be different from the second direction.
[0063] Here, the reference direction in the three-dimensional system of
coordinate
refers to a x direction, a y direction or a z direction in the three-
dimensional system of
coordinate, and the first reference direction may be same as the second
reference
direction, or may be different from the second reference direction. For
example, the first
parameter is a rate of change in the y direction of a component Hx of the
magnetic
induction intensity in the x direction in the three-dimensional system of
coordinate, i.e.,
aH-
/ay , which is referred as for brief.
In this case, the first parameter is generally
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referred as a magnetic gradient, thus, g xv is also referred as a magnetic
gradient in the y
direction of the component of the magnetic induction intensity in the x
direction.
However, those skilled in the art can understand that, the first parameter may
also be a
rate of change in a certain direction or another direction of a component of
the magnetic
induction intensity in the certain direction in other coordinate systems. And,
even in the
three-dimensional system of coordinate having the x, the y and the z
directions, the
first reference direction and the second reference direction are not limited
to the x, the y
and the z directions, but may be for example a xy direction, a yz direction or
the like.
And, the first direction may be same as the second direction, or may be
different from the
second direction. For example, correspondingly, the first parameter may also
be a rate of
change in the x direction of a component Hx of the magnetic induction
intensity in the
x direction in the three-dimensional system of coordinate, i.e., OH.10x, which
is
referred as gxx for brief. Therefore, regarding to the first parameter related
to the
magnetic induction intensity, so long as it can reflect the position of the
defect and the
degree of the defect of the pipe, the embodiments of the present invention do
not intended
to make any restriction.
[0064] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, after detecting the first parameter
related to the
magnetic induction intensity along the length direction of the pipe, a
graphical chart of
the magnitude of the first parameter versus a distance in the length direction
of the pipe
can be drawn. In particular, one end of the pipe detected is as an origin, a
distance of the
point detected from the origin is as a x coordinate, and the magnitude of the
first
parameter is as a y coordinate, a graphical chart in a x ¨ y coordinate system
is drawn,
for example, as shown in Figure 2. Thus, by viewing the graphical chart, the
position of
the defect and the degree of the defect of the pipe can be decided
intuitively, so that
displayed results are more intuitive.
[0065] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, the step of determining the degree of the
defect of
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the pipe based on the numerical value of the first parameter exceeding the
predetermined
threshold specifically comprises the steps of: determining the magnitude of
the defect of
the pipe based on an amplitude of the first parameter exceeding the
predetermined
threshold; and/or determining a length of the defect of the pipe based on a
length in
which the first parameter exceeds the predetermined threshold continuously.
[0066] As shown in Figure 2, at the same time of determining that there is the
defect in
the pipe, a detailed instance of the defect of the pipe can be determined
based on the
numerical value of the first parameter. For example, the magnitude of the
first parameter
exceeding the predetermined threshold can reflect the magnitude of the defect
of the pipe,
that is, the larger the magnitude of the first parameter exceeding the
predetermined
threshold is, the larger the magnitude of the defect of the pipe is. Also, the
length in
which the first parameter exceeds the predetermined threshold continuously can
reflect
the length of the defect of the pipe, that is, the longer the length in which
the first
parameter exceeds the predetermined threshold continuously is, the longer the
length of
the defect of the pipe is. Also, based on specific characteristic of the first
parameter and
different data processing methods, other conditions of the defect of the pipe
can be
reflected, and the embodiments of the present invention do not list them one
by one here.
[0067] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, the method further comprises the steps
of: detecting
a second parameter related to the magnetic induction intensity along the
length direction
of the pipe; determining whether the second parameter exceeds the
predetermined
threshold; determining a position at which the second parameter exceeds the
predetermined threshold as the position of the defect of the pipe; and
determining the
degree of the defect of the pipe based on the numerical value of the second
parameter
exceeding the predetermined threshold.
[0068] Here, in order to further improve accuracy of detection of the defect
of the pipe,
at the same time of detecting the first parameter related to the magnetic
induction
intensity along the length direction of the pipe, the method for detecting the
defect of the
pipe according to the first embodiment of the present invention further
detects the second
16
CA 2952294 2018-04-11
parameter related to the magnetic induction intensity along the length
direction of the
pipe. And preferably, the second parameter is a parameter associated with the
first
parameter, that is, the second parameter may be a rate of change in a fourth
direction of a
component of the magnetic induction intensity in a third direction in the
three-
dimensional system of coordinate. For example, the third direction and the
fourth
direction are also reference directions in the three-dimensional system of
coordinate, and
the second parameter is a rate of change in the z direction of a component H y
of the
magnetic induction intensity in the y direction in the three-dimensional
system of
coordinate, i.e., aH /az, which is referred as g vz for brief. Similarly, the
third direction
may be same as the fourth direction, or may be different from the fourth
direction. Thus,
it would help to further determine the position of the defect and the degree
of the defect
in the pipe in assistance with the first parameter. Of course, those skilled
in the art can
understand that, the second parameter in the method for detecting the defect
of the pipe
according to the first embodiment of the present invention is not limited to
the rate of
change in the fourth direction of the component of the magnetic induction
intensity in the
third direction in the three-dimensional system of coordinate as the first
parameter, as
long as the second parameter can reflect the defect of the pipe detected. And,
the second
parameter does not have to be associated with the first parameter, and thus,
the defect of
the pipe can be detected in a plurality of perspectives, which avoid an
instance in which a
.. detection of a certain parameter is invalid due to some particular cases.
[0069] In a procedure of further determining the position of the defect and
the degree
of the defect in the pipe in assistance with the first parameter, when the
position at which
the first parameter exceeds the predetermined threshold is same as the
position at which
the second parameter exceeds the predetermined threshold, this position is
determined as
a position at which there is the defect in the pipe, and when the position at
which the first
parameter exceeds the predetermined threshold is different from the position
at which the
second parameter exceeds the predetermined threshold, both of the position at
which the
first parameter exceeds the predetermined threshold and the position at which
the second
parameter exceeds the predetermined threshold are determined as the position
at which
there is the defect in the pipe. And, when the position at which the first
parameter
17
CA 2952294 2018-04-11
exceeds the predetermined threshold is different from the position at which
the second
parameter exceeds the predetermined threshold, a detail of the defect of the
pipe can be
determined based on the numerical value of the first parameter and the
numerical value of
the second parameter respectively. Preferably, when the position at which the
first
parameter exceeds the predetermined threshold is same as the position at which
the
second parameter exceeds the predetermined threshold, the degree of the defect
of the
pipe is determined based on a larger one of the numerical value of the first
parameter
exceeding the predetermined threshold and the numerical value of the second
parameter
exceeding the predetermined threshold. In particular, the magnitude of the
defect of the
pipe is determined based on a larger one of the magnitude of the first
parameter
exceeding the predetermined threshold and the magnitude of the second
parameter
exceeding the predetermined threshold, and the length of the defect of the
pipe is
determined based on a larger one of the length in which the first parameter
exceeds the
predetermined threshold and the length in which the second parameter exceeds
the
predetermined threshold. Of course, according to specific characteristics of
the first
parameter and the second parameter, for example, a practical selection of the
first
parameter and the second parameter as well as association between the first
parameter
and the second parameter or the like, when the position at which the first
parameter
exceeds the predetermined threshold is same as the position at which the
second
parameter exceeds the predetermined threshold, the degree of the defect of the
pipe at this
position can be determined based on the numerical value of the first parameter
and the
numerical value of the second parameter in other manners, for example, in a
manner of a
weighted sum of the numerical value of the first parameter and the numerical
value of the
second parameter. Those skilled in the art can understand that, the
embodiments of the
present invention do not intend to make any form of restriction thereto.
[0070] Further, those skilled in the art can understand that, in addition to
the first
parameter and the second parameter, the method for detecting the defect of the
pipe
according to the first embodiment of the present invention can further detect
other one or
more parameters related to the magnetic induction intensity along the length
direction of
the pipe. For example, taking a rate of change in a certain reference
direction of a
18
CA 2952294 2018-04-11
component of the magnetic induction intensity in another reference direction
in the three-
dimensional system of coordinate as example, rates of change in the three
directions of
(x y z) in the coordinate system of three components of (Hz, Hz, Hz) of
the
magnetic induction intensity in three reference directions in the three-
dimensional system
of coordinate can be detected respectively. Thus, a magnetic gradient matrix
including 9
elements in total can be constituted, the magnetic gradient matrix is referred
as G, and is
expressed as follows:
aft I ax aH, 1 ay al-ix az 9. 91, gAz
G=5HI ax aH ay aH =g g g
Yx YY Yz
[0071] aH ax aH, ay aHz az
_ z - -g g922- Formula 1
[0072] And, in a passive space, a divergence degree and a rotation degree of
the
magnetic induction intensity are 0, that is,
aft OH
z = 0
az ax
aH,, aH
-
Ox
aH, aH,
[0073] - & ay Formula 2
[0074] Thus, in the 9 elements in the magnetic gradient matrix, only values of
5
mutually independent elements need to be obtained to calculate values of all
elements in
the matrix; of course, in practical applications, an operator can select to
detect values of 6
elements, 7 elements, 8 elements or even all 9 elements, but actually, only 5
values need
to be measured to calculate to obtain other values, so as to obtain the above-
mentioned
magnetic gradient matrix.
[0075] At the time of detecting one or more parameters related to the magnetic
induction intensity, as explained in the above, a defect figure can be drawn
so as to make
19
CA 2952294 2018-04-11
status of the defect of the pipe more intuitive. Figure 2 is a schematic
diagram of a
graphical chart drawn by detecting 5 elements of a magnetic gradient matrix.
As shown
in Figure 2, by detecting values of 5 independent elements in the 9 elements
in the above-
described magnetic gradient matrix and drawing a curve of the values of the 5
elements
.. versus a distance in the x ¨ y coordinate system, 5 curves shown in this
figure are
obtained.
[0076] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, the predetermined threshold can be
selected by
those skilled in the art in terms of experience, or may be set as a fixed
value, for example,
average value of the first parameter in a length of the entire pipe or the
like, as long as
whether there is the defect as well as the degree of the defect can be
determined
accurately by comparing the first parameter and the predetermined threshold.
[0077] Preferably, in the method for detecting the defect of the pipe
according to the
first embodiment of the present invention, in order to make the comparison
between the
first parameter and the predetermined threshold to reflect whether there is
the defect
accurately, and make the numerical value of the first parameter reflect the
degree of the
defect accurately, the first parameter is processed and the predetermined
threshold is set
as follows. In particular, determining whether the first parameter exceeds the
predetermined threshold specifically includes: executing a differential
processing on the
first parameter; adding a variance of n times to/subtracting the variance of n
times from
an average value of the magnitude of the first parameter after differential
processing as
the predetermined threshold, wherein I n 3 ; and determining whether the first
parameter exceeds the predetermined threshold.
[0078] Hereinafter, it is explained by taking executing the differential
processing on the
.. magnetic induction intensity as example, and at the time of executing the
differential
processing, the magnetic induction intensity of adjacent points are
differentiated, as
shown in the following formulae 3:
CA 2952294 2018-04-11
AF = urn+ Ax) ¨ Mx)
L.' (0= lim
[0079] Ax ->0 Ax Formula 3
wherein, E(x) expresses the magnetic induction intensity at a position of X,
and
+ expresses the magnetic
induction intensity at a position of Ax . Thus, a
result after the differential processing of E (x) can be obtained, and it can
express a
magnitude of changes of the magnetic field at forward and backward position
and can be
used to determine whether there is the defect and the position at which the
defect is.
[0080] Here, at the time of determining whether there is the defect, a
variance of the
change of the magnetic induction intensity is derived for the detected
magnetic induction
intensity according to a principle of mathematical statistics, as shown in the
following
Formulae 4:
1 "
D(E)= Mx)-
12
[0081] n ¨1 c=1 Formula 4
- 1
E ¨ LE(x)
wherein, n x-1 . And,
according to the principle of mathematical
statistics, the defect can be decided when E (x)> nD(x)I , and a magnitude of
a value of n
is determined according to the magnitude of the defect to be detected, and
generally
3
[0082] Of course, those skilled in the art can understand, hereinbefore, it is
explained
by taking the magnetic induction intensity as example. When the first
parameter is other
parameter related to the magnetic induction intensity, it may be executed the
differential
processing in a similar manner, and determine corresponding threshold.
Therefore, in
order not to confuse a substantial feature of this application, it no longer
explained
detailed here.
21
CA 2952294 2018-04-11
[0083] Figure 3 is a schematic diagram of a curve obtained by executing the
differential processing on one curve in Figure 2. As shown in Figure 3, after
executing
the differential processing to one curve in Figure 2, top-and-bottom defect
threshold lines
representing the predetermined threshold are further provided in the curve in
Figure 3. In
figure 3, three times of variance is added to/subtracted from an average value
of the
magnitude of the first parameter after the differential processing, and the
result is set as
the top-and-bottom defect threshold lines. Thus, a case that the first
parameter after the
differential processing exceeds the predetermined threshold can be seen
intuitively from
Figure 3.
[0084] A part of the first parameter after the differential processing
exceeding the
predetermined threshold in Figure 3 is intercepted, to represent an abnormal
area in
which the first parameter related to the magnetic induction intensity has
abnormality in
entire length of the pipe intuitively. Figure 4 is a schematic diagram
presenting the
abnormal area after processing 5 curves shown in Figure 2. As shown in Figure
4,
wherein 3 curves have abnormality after being processed, and 2 curves do not
have
abnormality after being processed.
[0085] Then, the abnormal areas presented by the plurality of curves are
integrated
according to the above method. That is, abnormal areas at same position in the
x axis
direction are merged and maximum value thereof is taken, and abnormal areas at
different positions in the x axis direction are reserved. Thus, abnormal areas
presented
by the 5 curves as shown in Figure 4 after being processed are integrated into
a diagram,
so as to present the position of the defect and the degree of the defect in
the pipe clearly,
as shown in Figure 5. Figure 5 is a schematic diagram after integrating the
abnormal
areas presented after the processing as shown in Figure 4.
[0086] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, the step of determining whether the first
parameter
exceeds the predetermined threshold further comprises the steps of: in case
that there is
no pipe to be detected, detecting a third parameter related to the magnetic
induction
intensity at respective points along the length direction of the pipe, wherein
the third
22
CA 2952294 2018-04-11
parameter is a parameter which is same as the first parameter; and in the case
that the first
parameter is larger than the third parameter, optimizing the first parameter
with the third
parameter, and determining whether the optimized first parameter exceeds the
predetermined threshold.
[0087] In practice, even in case that there is no pipe to be detected, an
ambient field
having a certain magnetic induction intensity may be in a space to be
detected, so as to
make the first parameter related to the magnetic induction intensity not to
reflect
abnormality of the pipe accurately. Therefore, preferably, at the time of
determining
whether the first parameter exceeds the predetermined threshold, the first
parameter is
.. optimized by using data obtained by detecting the ambient field, so as to
make the first
parameter reflect the abnormality of the pipe more accurately. For example, in
case that
the first parameter is a rate of change in the y direction of a component Hx
of the
magnetic induction intensity in the x direction in the three-dimensional
system of
coordinate, i.e., Kry , a rate of change in the y direction of a component Hx
of the
magnetic induction intensity in the x direction in the three-dimensional
system of
coordinate are measured at the respective points along the length direction of
the pipe in a
same manner in case that there is no pipe to be detected, and it is referred
as gx,,' . Then,
the value of g'Y grY is as an optimized glY , and is determined whether it
exceeds the
predetermined threshold. Of course, those skilled in the art can understand
that, the first
parameter can be optimized with the third parameter in other manners, for
example, it
may decide that whether a magnitude of the first parameter is larger than a
peak
magnitude of the third parameter, so as to decide whether the detected first
parameter is
larger than data of the ambient field, and take the first parameter larger
than the data of
the ambient field as a reference of deciding whether it is the defect of the
pipe. Further, a
step of optimizing the first parameter with the data of the ambient field may
be before the
step of processing data of the first parameter and comparing with the
predetermined
threshold, or may be after the step of processing data of the first parameter
and
comparing with the predetermined threshold. If the first parameter is
optimized with the
data of the ambient field after processing the data of the first parameter and
comparing
23
CA 2952294 2018-04-11
with the predetermined threshold, the data of the ambient field should be
processed
correspond to the first parameter and compared with the predetermined
threshold. For
example, the third parameter of the ambient field is executed the differential
processing,
and top-and-bottom defect threshold lines are set. And in this case, abnormal
areas
caused by the ambient field can be taken out from the abnormal areas presented
by the
first parameter directly, or the abnormal areas presented by the first
parameter is
optimized with the abnormal areas caused by the ambient field.
[0088] In the method for detecting the defect of the pipe according to the
first
embodiment of the present invention, after optimizing the abnormal areas
presenting
magnetic abnormality according to the ambient field, the position of the
defect, the length
of the defect and the magnitude of the defect in the pipe can be decided
specifically
according to abnormal features in the respective magnetic abnormal area
including start
and end position of the magnetic abnormality and amplitude value of the
magnetic
abnormality, so as to obtain a final defect displaying result. A schematic
diagram of the
defect of the pipe can be further made by determining the position of the
defect by a
horizontal coordinate, determining the length of the defect by a length of the
horizontal
coordinate of the magnetic abnormal area and determining the magnitude of the
defect by
a vertical ordinate, for example, as shown in Figure 6. Figure 6 is a
schematic diagram of
the defect of the pipe made based on the abnormal areas integrated as shown in
Figure 5.
Thus, the defect in the pipe can be known more intuitively as compared to the
graphical
diagram, so that it is easy for a maintainer of the pipe to take repair and
maintenance
work with respect to the defect of the pipe, which reduces cost and
facilitates
convenience.
[0089] Thus, with the method for detecting the defect of the pipe according to
the first
.. embodiment of the present invention, the position of the defect in the pipe
can be
detected accurately, and the degree of the defect can be determined
accurately, so as to
save cost of detection and repair of the pipe and facilitate convenience of
the user.
[0090] A second embodiment of the present invention provides a device for
detecting
the defect of the pipe comprising the following modules being executed by a
computer: a
24
CA 2952294 2018-04-11
detecting unit configured to detect a first parameter related to a magnetic
induction
intensity along a length direction of the pipe; a deciding unit configured to
determine
whether the first parameter exceeds a predetermined threshold; and a control
unit
configured to determine a position at which the first parameter exceeds the
predetermined
.. threshold as the position of the defect of the pipe, and determining a
degree of the defect
of the pipe based on a numerical value of the first parameter exceeding the
predetermined
threshold.
[0091] Figure 7 is a schematic block diagram illustrating a device for
detecting the
defect of the pipe according to a second embodiment of the present invention.
As shown
in Figure 7, the device for detecting the defect of the pipe 100 according to
the second
embodiment of the present invention includes: a detecting unit 101 configured
to detect
the first parameter related to the magnetic induction intensity along the
length direction
of the pipe; a deciding unit 102 configured to determine whether the first
parameter
exceeds the predetermined threshold based on the first parameter detected by
the
detecting unit 101; and a control unit 103 configured to determine the
position at which
the first parameter exceeds the predetermined threshold as the position of the
defect of
the pipe based on a result of whether the first parameter exceeds the
predetermined
threshold determined by the deciding unit 102, and determine the degree of the
defect of
the pipe based on the numerical value of the first parameter exceeding the
predetermined
threshold.
[0092] In the above-described device for detecting the defect of the pipe, the
first
parameter is a rate of change in a second direction of a component of the
magnetic
induction intensity in a first direction in a three-dimensional system of
coordinate.
[0093] In the above-described device for detecting the defect of the pipe, the
first
.. direction is same as the second direction, or the first direction is
different from the second
direction.
[0094] In the above-described device for detecting the defect of the pipe, the
control
unit further comprises: a magnitude of defect determining module configured to
CA 2952294 2018-04-11
determine the magnitude of the defect of the pipe based on the magnitude of
the first
parameter exceeding the predetermined threshold: and/or a length of defect
determining
module configured to determine a length of the defect of the pipe based on a
length in
which the first parameter exceeds the predetermined threshold continuously.
[0095] In the above-described device for detecting the defect of the pipe, the
device
further comprises a drawing unit configured to draw a graphical chart of the
magnitude of
the first parameter versus a distance in the length direction of the pipe
based on the first
parameter detected by the detecting unit.
[0096] In the above-described device for detecting the defect of the pipe, the
detecting
unit is further configured to detect a second parameter related to the
magnetic induction
intensity along the length direction of the pipe; the deciding unit is further
configured to
determine whether the second parameter exceeds the predetermined threshold;
and the
control unit is further configured to determine a position at which the second
parameter
exceeds the predetermined threshold as the position of the defect of the pipe,
and
determine the degree of the defect of the pipe based on a numerical value of
the second
parameter exceeding the predetermined threshold.
[0097] In the above-described device for detecting the defect of the pipe,
when the
position at which the first parameter exceeds the predetermined threshold is
same as the
position at which the second parameter exceeds the predetermined threshold,
the control
unit determines the magnitude of the defect of the pipe based on the numerical
value of
the first parameter exceeding the predetermined threshold and the numerical
value of the
second parameter exceeding the predetermined threshold.
[0098] In the above-described device for detecting the defect of the pipe, the
second
parameter is a rate of change in a fourth direction of a component of the
magnetic
induction intensity in a third direction in the three-dimensional system of
coordinate.
26
CA 2952294 2018-04-11
[0099] In the above-described device for detecting the defect of the pipe, the
third
direction is same as the fourth direction, or the third direction is different
from the fourth
direction.
[00100] In the above-described device for detecting the defect of the pipe,
the first
direction, the second direction, the third direction and the fourth direction
are one of a x
direction, a y direction and a z direction in the three-dimensional system of
coordinate.
[00101] In the above-described device for detecting the defect of the pipe,
the deciding
unit further comprises: a differential processing module configured to execute
a
differential processing on the first parameter; a arithmetic processing module
configured
to add a variance of n times to/subtract the variance of n times from an
average value of
the first parameter after the differential processing of the differential
processing module
as the predetermined threshold, wherein 1 n 3; and a deciding module
configured to
determine whether the first parameter exceeds the predetermined threshold.
[00102] In the above-described device for detecting the defect of the pipe,
the detecting
unit is further configured to detect a third parameter related to the magnetic
induction
intensity along the length direction of the pipe in case that there is no pipe
to be detected,
wherein the third parameter is a parameter which is same as the first
parameter; and the
deciding unit is further configured to optimize the first parameter with the
third parameter
in the case that the first parameter is larger than the third parameter, and
determine
whether the optimized first parameter exceeds the predetermined threshold.
[00103] In the above-described device for detecting the defect of the pipe,
the detecting
unit is further configured to, in addition to the first parameter and the
second parameter
related to the magnetic induction intensity, further detect rates of change in
three
directions x, y and z in the coordinate system of three components Hx, H and
Hz of
the magnetic induction intensity in three reference directions in the three-
dimensional
system of coordinate along the length direction of the pipe respectively, to
constitute a
magnetic gradient matrix G including 9 elements in total:
27
CA 2952294 2018-04-11
- -
aft / ax aH, / ay aH / az gxx gxy gxz
G = aHv / ax OHy / ay aHy I Ez = gyõ gw
aH ax aHz ay aH, I az gzy gzz
[00104] _ z - -
[00105] In the above-described device for detecting the defect of the pipe,
the detecting
unit specifically comprises: a first three-components magnetic measuring
sensor, a
second three-components magnetic measuring sensor arranged symmetrically with
a
center of the detecting unit to the first three-components magnetic measuring
sensor, a
third three-components magnetic measuring sensor and a fourth three-components
magnetic measuring sensor arranged symmetrically with a center of the
detecting unit to
the third three-components magnetic measuring sensor, wherein the first, the
second, the
third and the fourth three-components magnetic measuring sensors are cross-
arranged in
a plane; and each magnetic measuring sensor in the first, the second, the
third and the
fourth three-components magnetic measuring sensors calculate a magnetic
gradient of a
central position of the cross by detecting values of magnetic induction
intensity in three
reference directions in the three-dimensional system of coordinate thereof, so
as to
measure the magnetic gradient matrix G at the central position of the cross:
OH, / ax alt / ay aHõ I az g 9,1, g,a
G = aHy / ax aHy / ay aHy / Oz = gyx gw
H
a I ax az I ay az I az
[00106] _ z H H gzx gzy gõ
B1r ¨ B,r B1, ¨B3v B2 - B0x x
Ax Ax Az
Bir ¨ B,y 131r B2z
BOz B2Y -130y
Ax Ax Az Az
131, ¨ Bõ B2y - BOY B2z - BOz
Ax Az Az
= _
[00107] wherein, Ay is a distance between the first three-components magnetic
measuring sensor and the second three-components magnetic measuring sensor, Az
is a
distance between the third three-components magnetic measuring sensor and the
fourth
28
CA 2952294 2018-04-11
three-components magnetic measuring sensor, Bõ is a component of the magnetic
induction intensity in the x direction measured by the first three-components
magnetic
measuring sensor, B,y is a component of the magnetic induction intensity in
the y
direction measured by the first three-components magnetic measuring sensor, Bõ
is a
component of the magnetic induction intensity in the z direction measured by
the first
three-components magnetic measuring sensor; B, is a component of the magnetic
induction intensity in the x direction measured by the second three-components
magnetic measuring sensor, B2y is a component of the magnetic induction
intensity in
the y direction measured by the second three-components magnetic measuring
sensor,
B2, is a component of the magnetic induction intensity in the z direction
measured by
the second three-components magnetic measuring sensor; Bõz is a component of
the
magnetic induction intensity in the x direction measured by the third three-
components
magnetic measuring sensor, Boy is a component of the magnetic induction
intensity in
the y direction measured by the third three-components magnetic measuring
sensor, Bõz
is a component of the magnetic induction intensity in the z direction measured
by the
third three-components magnetic measuring sensor; B3x is a component of the
magnetic
induction intensity in the x direction measured by the fourth three-components
magnetic
measuring sensor, 113y a component of the magnetic induction intensity in the
y
direction measured by the fourth three-components magnetic measuring sensor,
Bõ is a
component of the magnetic induction intensity in the z direction measured by
the fourth
three-components magnetic measuring sensor.
[00108] As explained above, in the method for detecting the defect of the pipe
according
to the first embodiment of the present invention and the device for detecting
the defect of
the pipe according to the second embodiment of the present invention, a rate
of change in
a certain reference direction of a component of the magnetic induction
intensity in
another reference direction in the three-dimensional system of coordinate can
be taken as
the first parameter related to the magnetic induction intensity, and in this
case the first
parameter is referred as the magnetic gradient generally, and the parameter is
detected by
29
CA 2952294 2018-04-11
using a corresponding magnetic gradient detection device. Figure 8 is a
schematic
diagram of a magnetic gradient detecting component according to the
embodiments of the
present invention. As shown in Figure 8, a magnetic gradient detecting
component 200
according to the embodiments of the present invention includes 4 three-
components
magnetic measuring sensors Bo, B1, B2 and B3 cross-arranged in a plane, a
magnetic
gradient of a central position of the cross is calculated by detecting values
of magnetic
induction intensities in three directions of each magnetic measuring sensor in
the 4 three-
components magnetic measuring sensors, so as to measure a magnetic gradient
matrix in
the central position of the cross. Of course, those skilled in the art can
understand that,
the value of the magnetic gradient measured by the magnetic gradient detecting
component 200 as shown in Figure 8 would be more accurate, however, in the
method for
detecting the defect of the pipe and the device for detecting the defect of
the pipe
according to the embodiments of the present invention, other types of magnetic
gradient
detecting component can be used to detect.
[00109] As shown in Figure 8, the magnetic gradient measuring device 100
adopting the
4 magnetic measuring sensors Bo, B1, B2 and B3 cross-arranged can detect the
magnetic
gradient, wherein each of the 4 magnetic measuring sensors Bo, B1, B2 and B3
is the
three-components magnetic measuring sensor, that is, it can measure a
component of the
magnetic induction intensity in the x, the y and the z direction. As shown in
Figure 8,
in one plane, Bo and B2 are provided symmetrically, Bi and B3 are provided
symmetrically, and a distance from the Bo to the center, a distance from the
B2 to the
center, a distance from the B1 to the center and a distance from the 131 to
the center are all
identical. Of course, those skilled in the art can understand that, in
practical applications,
as long as Bo and B2 are provided symmetrically and Bi and B3 are provided
symmetrically, a distance between the Bo and the B2 may be different from a
distance
between the Bi and B3, setting these distances to be identical is only for
convenience of
calculation of the magnetic gradient. Then, a magnetic gradient matrix at a
central point
obtained by the magnetic gradient measuring device 100 is:
CA 2952294 2018-04-11
aH, / ax OH, I ay alt I Oz gxx gxy gxz
G = aH 1 ax 8F1 I ay aH / az = g
Y), gYY gyz
aH ax / ay alt / g zx g4,
[00110] _ z - -
B1x ¨ B3x B ¨ B3v B2x BOx
Ax Ax Az
B1y ¨B3y (13, ¨B3x B2z ¨B0z ¨ Bõ
Ax I Ax Az Az
Br ¨13, B2 ¨BOv B2z ¨ B0z
, z y
Ax Az Az
-
[00111] In the above formula, Ax is a distance between the B1 sensor and the
B3 sensor,
Az is a distance between the Bo sensor and the B2 sensor, B1, is a component
of the
magnetic induction intensity in the x direction measured by the B1 sensor,
131, is a
component of the magnetic induction intensity in the y direction measured by
the B1
sensor, /312 is a component of the magnetic induction intensity in the z
direction
measured by the B1 sensor; B22 is a component of the magnetic induction
intensity in the
x direction measured by the B2 sensor, B2, is a component of the magnetic
induction
intensity in the y direction measured by the B2 sensor, B2 is a component of
the
magnetic induction intensity in the z direction measured by the B2 sensor; B02
is a
component of the magnetic induction intensity in the x direction measured by
the Bo
sensor, Boy is a component of the magnetic induction intensity in the y
direction
measured by the Bo sensor, Boz is a component of the magnetic induction
intensity in the
Z direction measured by the Bo sensor; Bit is a component of the magnetic
induction
intensity in the x direction measured by the B3 sensor, B3, a component of the
magnetic
induction intensity in the y direction measured by the B3 sensor, 113z is a
component of
the magnetic induction intensity in the z direction measured by the B3 sensor.
Values of
9 elements in the magnetic gradient matrix G can be obtained by measurement,
however,
similar to the above-mentioned, in practical application, since Formula 2 is
satisfied, only
values of 5 elements need to be obtained to derive the values of all 9
elements. And, from
the above Formula, value of any one of component Hõ H or Hz of the magnetic
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induction intensity in the three reference directions in the three-dimensional
system of
coordinate can be obtained from the above formula, for example, Kr, = (131. ¨
)/ Ax.
Thus, value of required elements can be calculated as necessary.
[00112] And, those skilled in the art can understand that, when the first
parameter
related to the magnetic induction intensity is not the magnetic gradient, for
example, it is
an attenuation decrement of the magnetic induction intensity, it is detected
by using
different device, and the embodiments of the present invention do not intend
to make any
restriction thereto.
[00113] A third embodiment of the present invention provides an apparatus for
detecting
the defect of the pipe including: a shelf provided above a pipe to be
detected; a sliding
track provided on the shelf and being able to slide along a length direction
of the shelf;
the device for detecting the defect of the pipe as described previously
slidably connected
to the sliding track through a slipper to detect the defect of the pipe of the
pipe to be
detected.
[00114] In the above-described apparatus for detecting the defect of the pipe,
an
actuating device for making the device for detecting the defect of the pipe to
slide in
uniform speed on the sliding track is provided.
[00115] In the above-described apparatus for detecting the defect of the pipe,
the
actuating device adopts any one of actuating manners including man-power, air
pressure
and hydraulic pressure.
[00116] Figure 9 is a schematic diagram illustrating an apparatus for
detecting the defect
of the pipe according to a third embodiment of the present invention. As shown
in Figure
9, an apparatus for detecting the defect of the pipe 10 includes a shelf 1, a
sliding track 2
and a device for detecting the defect of the pipe 3. The device for detecting
the defect of
.. the pipe 3 is disposed above a pipe by providing the shelf 1 on which the
sliding track 2
is provided. The device for detecting the defect of the pipe 3 is slidably
connected to the
sliding track 2 through a slipper. At the time of detection, the shelf 1 is
stationary, and the
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device for detecting the defect of the pipe 3 slides in uniform speed on the
sliding track 2
to detect the pipe. The device for detecting the defect of the pipe 3 can
slide in uniform
speed on the sliding track 2 by an actuating device, and the actuating device
can adopt
man-power, air pressure, hydraulic pressure or the like to control a manner of
an object
moving in uniform speed on a rack arbitrarily. In case that a length of the
shelf is less
than a length of a pipe to be detected, after a detection at a position at
which the shelf 1 is
completed, the shelf 1 is moved in position to start a next detection. In this
way, the
device for detecting the defect of the pipe can eliminate problems of shake of
moving the
track or inconsistent speed of moving caused by controlling movement manually
as large
as possible, so that an external interference is least and a result of
detection is more
accurate.
[00117] With the method for detecting the defect of the pipe, the device for
detecting the
defect of the pipe and the apparatus for detecting the defect of the pipe of
the present
invention, whether there is the defect in the pipe can be decided based on
parameters
related to the magnetic induction intensity, and the position of the defect of
the pipe can
be determined according to a position at which the parameters are abnormal,
and the
degree of the defect of the pipe can be determined according to numerical
values of the
parameters which are abnormal. Accordingly, the position of the defect and the
degree of
the defect in the pipe can be detected accurately.
[00118] Of course, the present invention also has many other embodiments, and
those
skilled in the art can make various kinds of corresponding changes and
variations
according to the present invention without departing from a spirit and an
essence of the
present invention, however, these corresponding changes and variations all
fall into a
scope sought for protection of attached claims of the present invention.
[00119] One skilled in the art will understand that the embodiment of the
present
invention as shown in the drawings and described above is exemplary only and
not
intended to be limiting.
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[00120] It will thus be seen that the objects of the present invention have
been fully and
effectively accomplished. The embodiments have been shown and described for
the
purposes of illustrating the functional and structural principles of the
present invention
and is subject to change without departure from such principles. Therefore,
this invention
includes all modifications encompassed within the spirit and scope of the
following
claims.
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