CN110043810A - Detection method, the packaging method of sensor and sensor of defect of pipeline - Google Patents

Abstract

The present invention provides a kind of detection method of defect of pipeline, the packaging method of sensor and sensor.The detection method includes: to be arranged in first sensor and second sensor on the corresponding position of pipeline along preset direction, and the region between the first sensor and second sensor of the pipeline is effective detection zone；Pumping signal is provided for the first sensor, so that the first sensor generates ultrasonic signal, the ultrasonic signal can be propagated along the preset direction；It detects whether the second sensor receives the ultrasonic signal, obtains testing result；It is determined in effective detection zone according to the testing result with the presence or absence of defect.The detection method realizes effective detection defect of pipeline by ultrasound examination defect.

Description

Pipeline defect detection method, sensor and sensor packaging method

technical field

The present invention relates to the technical field of detection, and in particular, to a method for detecting pipeline defects, a sensor and a method for packaging the sensor.

Background technique

As a means of transportation, pipelines have a harsh working environment and are prone to corrosion, fatigue damage, or expansion of potential defects inside the pipeline into cracks. threat. Therefore, detection of wall thinning, defects and cracks is important.

At present, the commonly used defect detection methods include eddy current detection, magnetic flux leakage detection and so on. In the commonly used detection methods, such as eddy current detection, the coil does not need to be in direct contact with the object to be measured, which is not suitable for parts with complex shapes, and the detection results are easily disturbed by the material itself and other factors.

It can be seen that the commonly used defect detection methods are not suitable for pipeline defect detection, and cannot effectively detect pipeline defects.

SUMMARY OF THE INVENTION

The present application is to provide a method for detecting pipeline defects, a sensor and a method for packaging the sensor, so as to solve the technical problem that pipeline defects cannot be effectively detected.

The embodiments of the present application are implemented in the following ways:

In a first aspect, the present invention provides a method for detecting pipeline defects, the method comprising:

Arrange the first sensor and the second sensor on the corresponding position of the pipeline along the preset direction, and the area between the first sensor and the second sensor of the pipeline is an effective detection area; provide the first sensor with excitation signal, so that the first sensor generates an ultrasonic signal, and the ultrasonic signal can propagate along the preset direction; detect whether the second sensor receives the ultrasonic signal, and obtain a detection result; according to the detection result It is determined whether there is a defect in the effective detection area.

Further, each of the first sensor and the second sensor includes a housing, a PCB coil and a plurality of permanent magnets arranged in the housing, and the first sensor and the second sensor are arranged in the pipeline along a preset direction. Before the corresponding position, the method further includes:

Arrange the plurality of permanent magnets above the PCB coil according to the preset direction; test the lift-off distance that needs to be satisfied between the PCB coil and the pipe surface; The plurality of permanent magnets are packaged in the housing to obtain the first sensor and the second sensor, so that the reserved distance after the PCB coil is packaged in the housing is smaller than the lift-off distance, wherein, The reserved distance represents the distance between the PCB coil and the end of the casing near the surface of the pipe.

Further, the lift-off distance that needs to be satisfied between the test PCB coil and the pipe surface includes:

changing the distance between the PCB coil and the pipe surface; testing the signal strength and signal-to-noise ratio of the signal received by the PCB coil; determining the lift-off distance according to the signal strength and the signal-to-noise ratio.

Further, encapsulating the PCB coil and the plurality of permanent magnets in the housing to obtain the first sensor and the second sensor according to the lift-off distance includes:

The PCB coil and the plurality of permanent magnets are encapsulated in a casing through an encapsulation medium; wherein, the encapsulation shape near the surface end of the pipe matches the shape of the surface of the pipe, so that the reserved distance is smaller than the lift. distance.

Further, before encapsulating the PCB coil and the plurality of permanent magnets in the housing through an encapsulation medium, the method further includes:

A layer of wear-resistant material is attached to the surface of the PCB coil to ensure that the reserved distance is smaller than the lift-off distance after the PCB coil is packaged in the housing.

Further, arranging the first sensor and the second sensor at positions corresponding to the pipeline along the preset direction includes:

The first sensor and the second sensor are arranged at corresponding positions of the pipeline along the axial or circumferential direction of the pipeline.

Further, determining whether there is a defect in the effective detection area according to the detection result includes:

If the ultrasonic signal is attenuated in the detection result, it is determined that there is a defect in the effective detection area, and the degree of attenuation of the ultrasonic signal represents the size of the defect.

In a second aspect, the present invention further provides a sensor, comprising: a casing, a PCB coil and a plurality of permanent magnets arranged in the casing; the plurality of permanent magnets are arranged on the PCB coil according to a preset direction; The reserved distance of the PCB coil packaged in the casing is smaller than the predicted lift-off distance, and the reserved distance represents the distance of the PCB coil from the casing near the surface end of the pipe to be tested.

In a third aspect, the present invention also provides a method for packaging a sensor, the sensor includes a housing, a PCB coil and a plurality of permanent magnets disposed in the housing, and the method includes:

Arrange the plurality of permanent magnets above the PCB coil according to a preset direction; test the lift-off distance that needs to be satisfied between the PCB coil and the surface of the pipeline to be tested; The plurality of permanent magnets are packaged in the housing to obtain the sensor, so that the reserved distance after the PCB coil is packaged in the housing is smaller than the lift-off distance, wherein the reserved distance represents the The distance of the PCB coil from the end of the housing near the surface of the pipe.

Further, encapsulating the PCB coil and the plurality of permanent magnets in the housing to obtain the sensor according to the lift-off distance includes:

The PCB coil and the plurality of permanent magnets are encapsulated in a casing through an encapsulation medium; wherein, the encapsulation shape near the surface end of the pipe matches the shape of the surface of the pipe, so that the reserved distance is smaller than the lift. distance.

In the method for detecting pipeline defects provided by the present invention, by setting the first sensor and the second sensor, it is detected whether the second sensor receives an ultrasonic signal, and whether there is a defect in the effective detection area is determined according to the detection result. The ultrasonic signal is used to determine whether there is a defect in the detection area of the pipeline, so as to effectively detect the pipeline defect.

In the sensor provided by the present invention, the reserved distance of the PCB coil encapsulated in the casing in the casing is smaller than the predicted lift-off distance, which meets the lift-off distance requirement of the sensor, so that the sensor can be used in pipelines Defect detection.

The sensor packaging method provided by the present invention, by testing the lift-off distance, effectively encapsulates the sensor according to the lift-off distance, so as to meet the requirements of the sensor for pipeline defect detection.

In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following specific embodiments of the present invention are given and described in detail in conjunction with the accompanying drawings.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. Other related figures are obtained from these figures.

FIG. 1 is a schematic structural diagram of a sensor provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of an internal structure of a sensor provided by an embodiment of the present invention;

3 is a flowchart of a method for packaging a sensor according to an embodiment of the present invention;

4 is a diagram of an example of a lift-off distance test provided by an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a packaged sensor provided by an embodiment of the present invention;

6 is a flowchart of a method for detecting a pipeline defect provided by an embodiment of the present invention;

FIG. 7 is an exemplary diagram of an axial sensor arrangement according to an embodiment of the present invention;

FIG. 8 is an example diagram of a circumferential sensor arrangement provided by an embodiment of the present invention;

9 is a schematic structural diagram of a fixing frame provided by an embodiment of the present invention;

10 is an example diagram of an axial detection result provided by an embodiment of the present invention;

11 is an example diagram of a detection result in a circumferential direction provided by an embodiment of the present invention;

FIG. 12 is an example diagram of a defect detection result provided by an embodiment of the present invention.

Icon: 100-sensor; 101-housing; 102-PCB coil; 103-multiple permanent magnets; 500-fixing frame; 501-fixing frame body; 502-adjusting nut; 503-roller.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations.

Thus, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present invention.

It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "middle", "upper", "lower", "horizontal", "inner", "outer", etc. are based on those shown in the accompanying drawings The orientation or positional relationship, or the orientation or positional relationship that the product of the invention is usually placed in use, is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, in order to simplify the description. The specific orientation configuration and operation are therefore not to be construed as limitations of the present invention. Furthermore, the terms "first", "second", etc. are only used to differentiate the description and should not be construed to indicate or imply relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that a component is required to be absolutely horizontal or overhang, but rather may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal than "vertical", it does not mean that the structure must be completely horizontal, but can be slightly inclined.

In the description of the present invention, it should be noted that, unless otherwise expressly specified and limited, the terms "arranged", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection connected, or integrally connected. It can be a mechanical connection or an electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The embodiments described below and features in the embodiments may be combined with each other without conflict.

Please refer to FIG. 1 , which is a sensor 100 provided by an embodiment of the present invention. When the sensor 100 is arranged on the surface to be tested of a pipeline, it can be used for detection of pipeline defects. The sensor 100 includes a housing 101 , a printed circuit board (PCB) coil 102 , and a plurality of permanent magnets 103 . The PCB coil 202 and the plurality of permanent magnets 103 are disposed in the housing 101 . The reserved distance of the PCB coil 102 encapsulated in the casing 101 is smaller than the predicted lift-off distance, and the reserved distance represents the distance between the PCB coil 102 and the casing 101 near the surface of the pipe.

Please refer to FIG. 2 , which is an internal structure diagram of the sensor 100 . It can be seen that the PCB coil 102 can be a racetrack-shaped coil or a coil of other shapes. Corresponding to the fabrication of the PCB coil 102, a double-layer flexible board may be used, and the line width may be 0.2 mm. When the sensor works, a high-frequency alternating current needs to be applied to the coil. For the plurality of permanent magnets 103, different arrangement forms can be adopted, such as the double-column periodic arrangement as shown in FIG. 2: the polarities of adjacent magnets on the same surface are opposite. The width of the straight line portion of the PCB coil 102 may match the length of the permanent magnets. After an excitation signal is applied to the PCB coil 102 , the excited ultrasonic waves propagate along the direction in which the plurality of permanent magnets 103 are arranged.

For the housing 101 , the housing 101 may be non-ferromagnetic stainless steel, and the PCB coil 102 and the plurality of permanent magnets 103 are packaged in the housing 101 . In order to enable the sensor 100 to excite and receive ultrasonic signals, so as to detect pipeline defects, the distance between the PCB coil and the surface of the pipeline to be tested is required. Therefore, the sensor 100 is specially packaged. In order to achieve fast and effective detection of internal or external defects of pipes of different diameters.

Please refer to FIG. 3 , which is a packaging method of a sensor provided by the present invention. The packaging method is applied to the packaging of the sensor 100 described above, and the packaging method includes:

Step 301: Arrange the plurality of permanent magnets in a preset direction above the PCB coil.

Step 302: Test the lift-off distance that needs to be satisfied between the PCB coil and the surface of the pipeline to be tested.

Step 303: Encapsulate the PCB coil and the plurality of permanent magnets in the housing according to the lift-off distance to obtain the sensor. The reserved distance after the PCB coil is packaged in the casing is smaller than the lift-off distance, wherein the reserved distance represents the distance between the PCB coil and the end of the casing close to the surface of the pipe.

The encapsulation method is described in detail below.

In step 301, the plurality of permanent magnets 103 need to be arranged on the PCB coil 102 according to a preset direction. For the preset direction, the propagation direction of the excitation ultrasonic wave generated by the PCB coil 102 is represented.

In step 102, the lift-off distance that needs to be satisfied between the PCB coil 102 and the pipeline on the surface to be tested needs to be tested. The test of the lift-off distance is to ensure that after the sensor 100 is arranged on the surface of the pipe, the sensor 100 can receive the ultrasonic signal propagating through the pipe, so as to detect whether the pipe is defective.

As for the specific testing process, the embodiment of the present invention provides an optional implementation, so the step 102 includes: changing the distance between the PCB coil and the surface of the pipe; testing the signal received by the PCB coil. Signal strength and signal-to-noise ratio; the lift-off distance is determined according to the signal strength and the signal-to-noise ratio.

In a specific implementation, before changing the distance, two groups of the PCB coils 102 and the plurality of permanent magnets 103 may be placed, one group is used as an excitation group, and the other group is used as a receiving group. Then, the excitation signal is applied to the excitation signal group, the distance between the two groups and the pipe surface is changed, and the signal strength and signal-to-noise ratio of the signals on the PCB coil 102 in the two groups are tested at the same time. As shown in Figure 4, which is an example diagram of the obtained test results, it can be seen that with the increase of the lift-off distance, the signal strength and signal-to-noise ratio both decrease. When the lift-off distance is 1mm, the The signal can be received, so it can be determined that the lift-off distance is 1 mm. That is to say, when the lift-off distance is greater than 1 mm, the PCB coil 102 cannot receive signals.

After the lift-off distance is obtained, step 103 may be performed, and packaging is performed according to the lift-off distance, so as to obtain the sensor 100 that can finally be used to detect defects. During the packaging process, because the PCB coil 102 will have a reserved distance in the casing 101, that is, the distance between the PCB coil 102 and the casing 101 near the surface of the pipe, all in the During packaging, the reserved distance must be smaller than the lift-off distance, so that the sensor 100 can still receive signals after being arranged on the pipeline.

For the embodiment of ensuring the lift-off distance, before step 103 is performed, the packaging method may further include: sticking a layer of wear-resistant material on the surface of the PCB coil 102 to ensure that the PCB coil 102 is packaged in the The reserved distance behind the casing 101 is smaller than the lift-off distance.

For the wear-resistant material, the thickness of the wear-resistant material should be as small as possible, and the wear-resistant material can protect the PCB coil 102 while ensuring the lift-off distance.

When step 303 is performed, step 303 may include: encapsulating the PCB coil 102 and the plurality of permanent magnets 103 in a casing through an encapsulation medium; wherein the encapsulation shape near the surface end of the pipe matches the shape of the surface of the pipe , so that the reserved distance is smaller than the lift-off distance.

Please refer to FIG. 5 , which is an example diagram of a packaged sensor. The encapsulation medium may be epoxy resin or other resin encapsulation medium. During the specific encapsulation, the PCB coil 102 affixed with the wear-resistant material is put into the casing 101 for potting. Note that the Wear resistant material ends up at the end of the casing 101 near the surface of the pipe. If the packaged sensor 100 is used for detection outside the pipe, the shape of the package close to the surface end of the pipe can be directly flat; if the packaged sensor 100 is used for detection inside the pipe, the shape close to the surface end of the pipe The shape of the package needs to be a curved surface, and the radius of the curved surface at this end is adapted to the inner diameter of the detected pipe. Taking a curved surface as an example, the specific implementation process of potting can be as follows: the flexible PCB board is bent and fixed correspondingly to form a curved surface and then placed into the casing 101 to complete the sealing of the casing 101 near the surface end of the pipe. , and then potting with epoxy resin. After the epoxy resin is cured, the bottom surface can be removed.

The sensor packaging method provided by the present invention, by testing the lift-off distance, effectively encapsulates the sensor according to the lift-off distance, so as to meet the requirements of the sensor for pipeline defect detection.

Please refer to FIG. 6 , which is a method for detecting pipeline defects provided by the present invention. The detection method utilizes the above-mentioned packaged sensor 100 to detect pipeline defects. The detection method includes:

Step 401: Arrange the first sensor and the second sensor at positions corresponding to the pipeline along a preset direction. Wherein, the area of the pipeline located between the first sensor and the second sensor is an effective detection area.

Step 402: Provide an excitation signal to the first sensor, so that the first sensor generates an ultrasonic signal, and the ultrasonic signal can propagate along the preset direction.

Step 403: Detect whether the second sensor receives the ultrasonic signal, and obtain a detection result.

Step 404: Determine whether there is a defect in the effective detection area according to the detection result.

The detection method uses the first sensor and the second sensor to detect whether the second sensor receives an ultrasonic signal, and determines whether there is a defect in the effective detection area according to the detection result. The ultrasonic signal is used to determine whether there is a defect in the detection area of the pipeline, so as to effectively detect the pipeline defect.

The implementation flow of steps 401 to 404 will be described in detail below.

In the detection method, when the ultrasonic signal generated by the first sensor propagates on the pipeline, it is called electromagnetic ultrasonic SH wave (horizontal polarized shear wave). The pipeline is equivalent to a solid propagation medium. In order to realize the excitation and reception of electromagnetic ultrasonic SH waves in the pipeline to meet the relevant detection of pipeline defects, the first sensor and the second sensor need to meet the requirements of using conditions for pipeline inspection.

The sensor 100 can be used as the first sensor and the second sensor, and can be arranged at the corresponding positions of the pipeline. It can be understood that the first sensor and the second sensor are the same, only One is used to excite the ultrasonic signal, and the other is used to receive the ultrasonic signal.

It should be noted that the packaging method of the sensor 100 may be implemented independently, or may be included in the detection method, and completed before step 401 is performed.

The step 401 may include: arranging the first sensor and the second sensor at corresponding positions of the pipeline along the axial or circumferential direction of the pipeline.

Please refer to FIG. 7 and FIG. 8 , which are schematic diagrams of the arrangement in the axial direction and the circumferential direction, respectively. The area of the pipe between the first sensor and the second sensor is an effective detection area. For the effective detection area, a plurality of groups of first sensors and second sensors may be respectively set to form a plurality of effective detection areas, respectively, to detect whether there is a defect in the plurality of effective detection areas. The first sensor and the second sensor may also be moved, so that the effective detection area changes correspondingly with the movement of the sensors. In the embodiment of moving the sensor, when the first sensor and the second sensor are arranged at corresponding positions on the pipeline, a movable sensor can be provided for the first sensor and the second sensor. Mounting frame.

Referring to FIG. 9 , an embodiment of the present invention provides an optional fixing frame 500 . The fixing frame 500 includes a fixing frame body 501 , an adjusting nut 502 and a roller 503 . The sensor 200 is fixed on the fixing frame body 501, and the roller 503 can support the entire fixing frame body 501, and can realize the movement of the sensor 100 along the pipe wall according to the detection requirement; the adjusting nut 502 is used for Adjust the distance between the sensor 100 and the surface to be tested, and try to keep the gap as small as possible according to the roughness of the surface to be tested. At the same time, the sensor 100 can be adapted to pipes of different diameters. It should be noted that when the sensor 100 is fixed on the fixing frame 500, according to the thickness of the wear-resistant material layer during packaging, it should be ensured that the gap between the sensor 100 and the surface of the pipe under test does not exceed the lift-off distance minus the distance. If the thickness of the wear-resistant material layer is removed, for example, the lift-off distance value is 1, and the wear-resistant material layer is 0.2 mm, it should be ensured that the gap between the sensor 100 and the surface of the pipe under test does not exceed 0.8 mm.

After step 401 is performed, step 402 may be performed to provide the first sensor with an excitation signal, so that the first sensor generates an ultrasonic signal, and the ultrasonic signal can propagate along the preset direction.

The excitation signal may be high-frequency alternating current, and the frequency of the high-frequency alternating current corresponds to the width of the permanent magnet. In general, the width of the permanent magnet is the excitation ultrasonic wave. For the detection of the pipeline, when the excitation frequency is 500kHZ, the width of the selected permanent magnet is 3mm.

After the excitation signal is provided, the first sensor generates an ultrasonic signal, and the ultrasonic signal propagates in the preset direction. At this time, step 403 can be performed: detect whether the second sensor receives the ultrasonic signal, and obtain Test results.

Step 404 is then executed: determining whether there is a defect in the effective detection area according to the detection result.

Please refer to FIG. 10 and FIG. 11 , which are two detection results provided by the embodiment of the present invention. The two detection results are the detection results in the axial direction and the circumferential direction respectively. It can be seen that the signal received on the second sensor Preferably, it is determined that there is no defect in the effective detection area.

Please refer to FIG. 12 , which is another detection result provided by the embodiment of the present invention. In this detection result, the second sensor can receive an ultrasonic signal, but the ultrasonic signal is attenuated, and the effective detection area is determined. There are defects inside, and the degree of attenuation of the ultrasonic signal characterizes the size of the defects. It can be understood that, the greater the defect existing in the effective detection area, the greater the attenuation of the ultrasonic signal.

Therefore, for the detection result, if an ultrasonic signal is detected on the second sensor, it needs to be judged according to the ultrasonic signal. If the ultrasonic signal is not attenuated, it is determined that there is no defect in the effective detection area; Attenuation occurs, there is a defect in the effective detection area, and the degree of attenuation of the ultrasonic signal characterizes the size of the defect. In addition, if the ultrasonic signal is not detected on the second sensor, it is still determined that there is a defect in the effective detection area, because in the case of a serious defect, the attenuation of the ultrasonic signal is relatively large, or even disappears, so When the ultrasonic signal is not detected, it is also judged that there is a defect, and the defect is relatively large.

The detection method provided by the present invention detects whether the second sensor receives an ultrasonic signal by setting the first sensor and the second sensor, and determines whether there is a defect in the effective detection area according to the detection result. The ultrasonic signal is used to determine whether there is a defect in the detection area of the pipeline, so as to effectively detect the pipeline defect.

In the embodiments provided in this application, it should be understood that the disclosed apparatus and method may also be implemented in other manners. The apparatus embodiments described above are merely illustrative, for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality and possible implementations of apparatuses, methods and computer program products according to various embodiments of the present invention. operate. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code that contains one or more functions for implementing the specified logical function(s) executable instructions. It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It is also noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented in dedicated hardware-based systems that perform the specified functions or actions , or can be implemented in a combination of dedicated hardware and computer instructions.

In addition, each functional module in each embodiment of the present invention may be integrated to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a kind of detection method of defect of pipeline characterized by comprising

First sensor and second sensor are arranged on the corresponding position of pipeline along preset direction, the pipeline is located at institute Stating the region between first sensor and second sensor is effective detection zone；

Pumping signal is provided for the first sensor, so that the first sensor generates ultrasonic signal, the ultrasonic wave Signal can be propagated along the preset direction；

It detects whether the second sensor receives the ultrasonic signal, obtains testing result；

It is determined in effective detection zone according to the testing result with the presence or absence of defect.

2. detection method according to claim 1, which is characterized in that the first sensor and the second sensor are equal Including shell and setting in the intracorporal PCB coil of the shell and multiple permanent magnets, by first sensor and second sensor edge Before preset direction is arranged on the corresponding position of pipeline, the method also includes:

The multiple permanent magnet is arranged according to the preset direction above the PCB coil；

Test the lift off for needing to meet between the PCB coil and pipe surface；

The PCB coil and the multiple permanent magnet are encapsulated in the shell according to the lift off and obtain described first Sensor and the second sensor, so that the preset space after the PCB coil is encapsulated in the shell is less than described mention Separation from, wherein the preset space characterize the PCB coil apart from the shell close to the pipe surface end away from From.

3. according to the method described in claim 2, it is characterized in that, needing to meet between test PCB coil and pipe surface Lift off includes:

Change the distance between the PCB coil and pipe surface；

Test the signal strength and signal-to-noise ratio of the signal that the PCB coil receives；

The lift off is determined according to the signal strength and the signal-to-noise ratio.

4. detection method according to claim 2, which is characterized in that according to the lift off by the PCB coil and The multiple permanent magnet, which is encapsulated in the shell, obtains the first sensor and the second sensor includes:

The PCB coil and the multiple permanent magnet are encapsulated in shell by encapsulation medium；

Wherein, matched close to the encapsulation shape at the pipe surface end with the shape of the pipe surface so that it is described reserve away from From less than the lift off.

5. according to the method described in claim 4, it is characterized in that, passing through by the PCB coil and the multiple permanent magnet Before encapsulation medium is encapsulated in shell, the method also includes:

One layer of wear-resistant material is pasted on the PCB coil surface, to guarantee that the PCB coil is described pre- after being encapsulated in the shell Distance is stayed to be less than the lift off.

6. detection method according to claim 1, which is characterized in that by first sensor and second sensor along default side Include: to being arranged on the corresponding position of pipeline

First sensor and second sensor along the axial direction of the pipeline or are arranged circumferentially on the corresponding position of pipeline.

7. detection method according to claim 1, which is characterized in that determine effective detection according to the testing result Include: with the presence or absence of defect in region

If ultrasonic signal described in the testing result is decayed, existing defects in effective detection zone, institute are determined State the size of the attenuation degree characterization defect of ultrasonic signal.

8. a kind of sensor characterized by comprising shell and setting are in the intracorporal PCB coil of the shell and multiple permanent magnets； The multiple permanent magnet is arranged in the PCB coil according to preset direction；It is intracorporal pre- that the PCB coil is encapsulated in the shell Distance is stayed to be less than the lift off of prediction, the preset space characterizes the PCB coil apart from the shell close to test tube The distance of road endmost surface.

9. a kind of packaging method of sensor, which is characterized in that the sensor includes shell and is arranged intracorporal in the shell PCB coil and multiple permanent magnets, which comprises

The multiple permanent magnet is arranged according to preset direction above the PCB coil；

Test the lift off for needing to meet between the PCB coil and pipe under test surface；

The PCB coil and the multiple permanent magnet are encapsulated in the shell according to the lift off and obtain the sensing Device, so that the preset space after the PCB coil is encapsulated in the shell is less than the lift off, wherein described reserved Distance characterizes distance close to the pipe surface end of the PCB coil apart from the shell.

10. according to the method described in claim 9, it is characterized in that, according to the lift off by the PCB coil and described Multiple permanent magnets, which are encapsulated in the shell, to be obtained the sensor and includes:

The PCB coil and the multiple permanent magnet are encapsulated in shell by encapsulation medium；

Wherein, matched close to the encapsulation shape at the pipe surface end with the shape of the pipe surface so that it is described reserve away from From less than the lift off.