1. A built-in pipeline damage detection system, comprising: at least two pipeline damage detection device, it is a plurality of pipeline damage detection device interval is arranged in by the pipeline, pipeline damage detection device includes:

the hydraulic pipe comprises a hydraulic main pipe and hydraulic branch pipes, the hydraulic branch pipes are arranged on the hydraulic main pipe, the hydraulic main pipe is also provided with a liquid injection pipe, and the hydraulic main pipe is arranged in the pipeline to be measured; the end part of the hydraulic branch pipe, which is far away from the hydraulic main pipe, is opened and is arranged towards the inner wall of the pipeline to be measured;

the detection structure comprises a piston head and a piezoelectric sensor, the piston head is movably arranged in the hydraulic branch pipe, and the piezoelectric sensor is arranged on one surface of the piston head, which deviates from the hydraulic main pipe.

2. The built-in pipe damage detecting system according to claim 1, wherein the hydraulic pipes of the plurality of pipe damage detecting devices are arranged to face each other.

3. The built-in pipeline damage detection system according to claim 2, wherein the distance between every two pipeline damage detection devices along the axial direction of the tested pipeline is as follows:

L1＝n*v1/4f1

where n is an odd number, n is 1,3,5,7 … …, v1 is the wave speed of the excitation signal of the piezoelectric sensor, and f1 is the frequency of the excitation signal of the piezoelectric sensor.

4. The system according to any one of claims 1 to 3, wherein a plurality of hydraulic branch pipes are provided, the plurality of hydraulic branch pipes are uniformly arranged on the hydraulic main pipe, and a plurality of detection structures are provided, and the plurality of detection structures correspond to the plurality of hydraulic branch pipes one to one.

5. The system of claim 4, wherein the hydraulic manifold is a ring-shaped pipe, and the plurality of hydraulic branch pipes are arranged around the periphery of the hydraulic manifold at regular intervals.

6. The built-in pipeline damage detection system according to claim 5, wherein the center of the hydraulic main pipe is concentrically arranged with the center of the inner wall of the pipeline to be detected, and the plurality of hydraulic branch pipes have the same length.

7. The built-in pipeline damage detection system according to any one of claims 1 to 3, wherein a gap is formed between the hydraulic pipe and an inner wall of the pipeline to be detected.

8. The system of any one of claims 1 to 3, wherein the piston head has an insertion slot facing away from the hydraulic manifold, the piezoelectric sensor is inserted into the insertion slot, and a surface of the piezoelectric sensor facing away from the insertion slot passes over a surface of the piston head facing away from the hydraulic manifold.

9. The system of any of claims 1 to 3, wherein the piezoelectric sensor is a guided wave sensor.

10. A method for detecting damage to a built-in pipeline, comprising the system according to any one of claims 1 to 9, wherein the number of the pipeline damage detection devices is two, and the two pipeline damage detection devices are a first pipeline damage detection device and a second pipeline damage detection device, respectively, and the method comprises the steps of:

hydraulic pressure is respectively injected into the first pipeline damage detection device and the second pipeline damage detection device through the liquid injection pipe, the hydraulic pressure enters the hydraulic branch pipe through the hydraulic main pipe, and when the hydraulic pressure reaches a first preset value, the piezoelectric sensor is tightly pressed to be tightly attached to the inner wall of the pipeline to be detected;

the piezoelectric sensors of the first pipeline damage detection device and the second pipeline damage detection device transmit the acquired first signal set to a terminal;

the terminal obtains damage state parameters of the detected pipeline according to the first signal set, and when the detected pipeline has damage points, the terminal judges the position of the damage points of the detected pipeline according to the first signal set;

when the position of the damage point cannot be judged according to the first signal set, unloading the hydraulic pressure, moving the first pipeline damage detection device and/or the second pipeline damage detection device along the axis direction of the detected pipeline, then loading the hydraulic pressure to reach a first preset value, and pressing the piezoelectric sensor to be tightly attached to the inner wall of the detected pipeline;

the piezoelectric sensor transmits the acquired second signal set to the terminal;

and the terminal obtains damage state parameters of the detected pipeline according to the first signal set and the second signal set and judges the position of a damage point of the detected pipeline.

Background

The pipeline is a channel for transporting gas or liquid, but the pipeline itself may be damaged during long-term use, and needs to be predicted in advance through detection so as to avoid gas or liquid in the pipeline from leaking out.

Currently, in pipeline damage detection construction, a radiation inspection method and an ultrasonic inspection method are generally adopted. For the pipeline passing through the partition wall structure, when the construction space on one side of the partition wall structure is insufficient, the damage detection construction can be carried out only on the other side of the partition wall structure, and the ultrasonic flaw detection method cannot be applied because the damage part cannot be approached; when other metal parts are directly attached to the pipeline on one side of the partition wall with insufficient construction space, the detection result of the radiographic inspection method is inaccurate due to the interference of the metal parts.

Obviously, the existing pipeline damage detection method cannot ensure that the detection device is attached to the detected object in a close range, so that the detection cannot be carried out or the detection result is inaccurate.

Disclosure of Invention

The invention provides a built-in pipeline damage detection system and a detection method thereof, which are used for solving the defects that the detection device cannot be attached to a detected object in a short distance by the existing pipeline damage detection method in the prior art, so that the detection cannot be carried out or the detection result is inaccurate, and realizing the improvement of the detection accuracy.

The invention provides a built-in pipeline damage detection system, which comprises: at least two pipeline damage detection device, it is a plurality of pipeline damage detection device interval is arranged in by the pipeline, pipeline damage detection device includes:

the hydraulic pipe comprises a hydraulic main pipe and hydraulic branch pipes, the hydraulic branch pipes are arranged on the hydraulic main pipe, the hydraulic main pipe is also provided with a liquid injection pipe, and the hydraulic main pipe is arranged in the pipeline to be measured; the end part of the hydraulic branch pipe, which is far away from the hydraulic main pipe, is opened and is arranged towards the inner wall of the pipeline to be measured;

the detection structure comprises a piston head and a piezoelectric sensor, the piston head is movably arranged in the hydraulic branch pipe, and the piezoelectric sensor is arranged on one surface of the piston head, which deviates from the hydraulic main pipe.

According to the built-in pipeline damage detection system provided by the invention, the hydraulic pipes of the pipeline damage detection devices are arranged opposite to each other.

According to the built-in pipeline damage detection system provided by the invention, along the axial direction of a detected pipeline, the distance between every two pipeline damage detection devices is as follows:

L1＝n*v1/4f1

where n is an odd number, n is 1,3,5,7 … …, v1 is the wave speed of the excitation signal of the piezoelectric sensor, and f1 is the frequency of the excitation signal of the piezoelectric sensor.

According to the built-in pipeline damage detection system provided by the invention, a plurality of hydraulic branch pipes are arranged, the plurality of hydraulic branch pipes are uniformly distributed on the hydraulic main pipe, a plurality of detection structures are also arranged, and the plurality of detection structures correspond to the plurality of hydraulic branch pipes one by one.

According to the built-in pipeline damage detection system provided by the invention, the hydraulic main pipe is an annular pipeline, and the plurality of hydraulic branch pipes are uniformly arranged on the periphery of the hydraulic main pipe at intervals.

According to the built-in pipeline damage detection system provided by the invention, the center of the hydraulic main pipe and the center of the inner wall of the pipeline to be detected are concentrically arranged, and the lengths of the hydraulic branch pipes are the same.

According to the built-in pipeline damage detection system provided by the invention, a gap is formed between the hydraulic pipe and the inner wall of the pipeline to be detected.

According to the built-in pipeline damage detection system provided by the invention, the piston head is provided with an embedded groove facing away from the hydraulic manifold, the piezoelectric sensor is embedded in the embedded groove, and the surface of the piezoelectric sensor facing away from the embedded groove passes over the surface of the piston head facing away from the hydraulic manifold.

According to the built-in pipeline damage detection system provided by the invention, the piezoelectric sensor is a guided wave sensor.

The invention also provides a built-in pipeline damage detection method, which comprises the built-in pipeline damage detection system, wherein the number of the pipeline damage detection devices is two, the two pipeline damage detection devices are respectively a first pipeline damage detection device and a second pipeline damage detection device, and the method comprises the following steps:

hydraulic pressure is respectively injected into the first pipeline damage detection device and the second pipeline damage detection device through the liquid injection pipe, the hydraulic pressure enters the hydraulic branch pipe through the hydraulic main pipe, and when the hydraulic pressure reaches a first preset value, the piezoelectric sensor is tightly pressed to be tightly attached to the inner wall of the pipeline to be detected;

the piezoelectric sensors of the first pipeline damage detection device and the second pipeline damage detection device transmit the acquired first signal set to a terminal;

the terminal obtains damage state parameters of the detected pipeline according to the first signal set, and when the detected pipeline has damage points, the terminal judges the position of the damage points of the detected pipeline according to the first signal set;

when the position of the damage point cannot be judged according to the first signal set, unloading the hydraulic pressure, moving the first pipeline damage detection device and/or the second pipeline damage detection device along the axis direction of the detected pipeline, then loading the hydraulic pressure to reach a first preset value, and pressing the piezoelectric sensor to be tightly attached to the inner wall of the detected pipeline;

the piezoelectric sensor transmits the acquired second signal set to the terminal;

and the terminal obtains damage state parameters of the detected pipeline according to the first signal set and the second signal set and judges the position of a damage point of the detected pipeline.

According to the built-in pipeline damage detection system and the detection method thereof, the piston head is driven to move through hydraulic pressure, so that the piezoelectric sensor can be attached to the detected pipeline tightly, the accuracy of pipeline damage detection is realized, in addition, pipeline damage detection can be carried out on each position of the detected pipeline through a plurality of pipeline damage detection devices, when one pipeline damage detection device detects a damage point, the damage point can be detected through the other pipeline damage detection device, the position of the damage point is judged so as to be convenient for maintenance, compared with the existing method, the built-in pipeline damage detection system provided by the application can carry out detection from the inner side of the pipeline, the detection accuracy is high, and the position of the damage point can be determined so as to be convenient for maintenance.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a built-in pipeline damage detection system provided by the present invention;

fig. 2 is a schematic structural diagram of a pipeline damage detection device of a built-in pipeline damage detection system provided by the invention;

FIG. 3 is an enlarged schematic view at A in FIG. 2;

reference numerals:

10: a pipe to be tested; 201: first pipeline damage test 202: second pipeline damage detection

A measuring device; a measuring device;

21: a hydraulic tube; 211: a hydraulic main pipe; 212: a hydraulic branch pipe;

213: a liquid injection pipe; 22: detecting the structure; 221: a piston head;

222: a piezoelectric sensor.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The built-in pipe damage detection system and the detection method thereof of the present invention will be described with reference to fig. 1 to 3.

Referring to fig. 1 to 3, the built-in pipeline damage detection system includes: at least two pipeline damage detection device, a plurality of pipeline damage detection device interval is arranged in by survey pipeline 10, pipeline damage detection device includes:

the hydraulic pipe 21 comprises a hydraulic main pipe 211 and hydraulic branch pipes 212, the hydraulic branch pipes 212 are arranged on the hydraulic main pipe 211, the hydraulic main pipe 211 is also provided with a liquid injection pipe 213, and the hydraulic main pipe 211 is arranged in the pipeline 10 to be tested; the end of the hydraulic branch pipe 212, which is away from the hydraulic main pipe 211, is open and is arranged towards the inner wall of the pipeline 10 to be tested;

the detection structure 22 comprises a piston head 221 and a piezoelectric sensor 222, the piston head 221 is movably arranged in the hydraulic branch pipe 212, and the piezoelectric sensor 222 is arranged on the side, facing away from the hydraulic manifold 211, of the piston head 221.

The hydraulic pipe 21 is a sealed tubular structure, liquid can be injected into the hydraulic pipe 21 through the liquid injection pipe 213 to load hydraulic pressure, when the fluid flows to the hydraulic branch pipe 212, the piston head 221 embedded in the hydraulic branch pipe 212 can be pushed to move, and then the piezoelectric sensor 222 is driven to move, and due to the opening at the end part of the hydraulic branch pipe 212, the piezoelectric sensor 222 can be tightly attached to the inner wall of the pipeline 10 to be detected, so that the detection is realized.

The piezoelectric sensor 222 can detect loss defects on the surface and inside of the sample by the emitted guided waves, and can realize accurate detection when the piezoelectric sensor is attached to a measured object, and preferably, the piezoelectric sensor 222 provided herein is a guided wave sensor.

The number of the pipe damage detection devices is at least two, and further damage detection can be performed in a plurality of orientations of the pipe 10 in the axial direction of the pipe 10. Because it is difficult to know that a single pipeline damage detection device is positioned on the left side or the right side of the pipeline damage detection device when detecting a damage point, at least two pipeline damage detection devices are arranged so as to judge the direction of the damage point and increase the detection range.

In this embodiment, the piston head 221 is driven to move by hydraulic pressure, so that the piezoelectric sensor 222 can be tightly attached to the detected pipeline 10, and the accuracy of detecting the pipeline damage is realized, and the pipeline damage can be detected at each position of the detected pipeline 10 by a plurality of pipeline damage detection devices, when one pipeline damage detection device detects a damage point, the damage point can be detected by the other pipeline damage detection device, so as to determine the position of the damage point, so as to facilitate maintenance.

Referring to fig. 1, in an embodiment of the present invention, the hydraulic pipes 21 of the pipeline damage detecting device are arranged opposite to each other.

That is, the plurality of pipe damage detecting devices are identical in structure, and the hydraulic branch pipes 212 of the hydraulic manifold 211 of each pipe damage detecting device are identical in orientation and arrangement, so that the position of the damage point can be known more accurately according to the positions of the hydraulic branch pipes 212.

Specifically, in an embodiment, the distance between two adjacent pipeline damage detection devices is movable, and along the axial direction of the pipeline 10 to be detected, the distance between every two pipeline damage detection devices is as follows:

L1＝n*v1/4f1

where n is an odd number, n is 1,3,5,7 … …, v1 is the wave speed of the excitation signal of the piezoelectric sensor 222, and f1 is the frequency of the excitation signal of the piezoelectric sensor 222.

Because the detection range of the piezoelectric sensor 222 of each pipeline damage detection device is limited, the pipeline damage detection devices can be moved according to the distance, and the positions of the damage points can be known, when the two pipeline damage detection devices are at the closest distance, the part of the pipeline 10 to be detected between the two pipeline damage detection devices can be detected by the piezoelectric sensor 222 in the pipeline damage detection device, and the part of the pipeline 10 to be detected on the other side of the pipeline damage detection devices can not be detected by the other pipeline damage detection device.

In this embodiment, the number of the pipeline damage detection devices is two, the two pipeline damage detection devices are independent from each other, but the piezoelectric sensor 222 of each pipeline damage detection device is connected to the terminal in a telecommunication manner, so that the terminal can analyze the damage state parameters of the pipeline 10 to be detected according to the detection condition and judge the position of the damage point of the pipeline 10 to be detected.

In another embodiment, the two pipeline damage detection devices are connected through a telescopic connecting rod, so that the stability of the whole built-in pipeline damage detection system is further ensured on the basis of ensuring the movement between the two devices. Further, in order to realize controllable regulation, the telescopic link includes the loop bar of locating one of them pipeline damage detection device and the pole that inlays of locating another pipeline damage detection device, inlays the pole and inlays and locate the loop bar and remove, is equipped with the cylinder in the loop bar, the output shaft of cylinder with inlay pole fixed connection, like this, only need fix one of them pipeline damage detection device, another pipeline damage detection device's of accessible this cylinder drive removal. Of course, in other embodiments, when more pipeline damage detection devices are arranged, connection can be achieved through the above structure, which is not described in detail.

In another embodiment, the positions of two adjacent pipeline damage detection devices are not movable, and the distance between the two pipeline damage detection devices is the minimum distance, so that the position of a damaged point can be identified while detecting.

Referring to fig. 2, in an embodiment of the present invention, a plurality of hydraulic branch pipes 212 are provided, a plurality of hydraulic branch pipes 212 are uniformly distributed on the hydraulic main pipe 211, a plurality of detection structures 22 are also provided, and a plurality of detection structures 22 correspond to the plurality of hydraulic branch pipes 212 one to one.

Thus, when the hydraulic pressure is applied to the hydraulic pipe 21, the detection structures 22 of the plurality of hydraulic branch pipes 212 can be driven simultaneously to perform pipeline damage detection, so that the range of pipeline damage detection is increased, and the positions of damage points in the radial direction can be further analyzed and obtained through detection by the plurality of detection structures 22.

Specifically, in this embodiment, the hydraulic manifold 211 is an annular pipe, and the plurality of hydraulic branch pipes 212 are uniformly spaced around the periphery of the hydraulic manifold 211.

In this way, when hydraulic pressure is applied, it is ensured that the hydraulic branch pipes are simultaneously applied with pressure, and the hydraulic branch pipes 212 are arranged toward the inner wall of the measured pipe 10, so that the piezoelectric sensor 222 can be closely attached to the inner wall of the measured pipe 10. In other embodiments, the hydraulic manifold 211 may be a coil-wound pipe, and the plurality of hydraulic branch pipes 212 are disposed on the hydraulic manifold 211, which will not be described in detail.

The hydraulic manifold 211 is a ring-shaped pipe structure, and the number of the hydraulic branch pipes 212 is six.

By arranging the six hydraulic branch pipes 212, the detection of all the positions of the circumference of the inner wall of the pipeline can be basically realized, so that the efficiency of detecting the damage of the pipeline is improved, and meanwhile, the positions of the damage points in the radial direction can be obtained through further analysis. Of course, more hydraulic branch pipes 212 and corresponding detection structures 22 may be provided as needed, and will not be described in detail. When the six hydraulic branch pipes 212 are arranged, the piezoelectric sensor 222 is tightly attached to the inner wall of the pipeline 10 to be detected, so that the whole detection device is in a claw shape, the detection device is prevented from toppling over, and the detection device is kept stable.

In addition, the center of the hydraulic manifold 211 is concentrically arranged with the center of the inner wall of the pipe 10 to be measured, and the lengths of the plurality of hydraulic branch pipes 212 are the same.

Therefore, the pressure of the piston head 221 at each position can be ensured to be the same, so that damage detection can be performed on a plurality of positions of the inner wall of the detected pipeline 10 at the same time, and the detection efficiency is further improved.

In another embodiment, the center of the hydraulic manifold 211 is eccentric to the center of the inner wall of the measured pipe 10, so that when the hydraulic pipe 21 is placed in the measured pipe 10, the position is fixed, the pipe is not easy to rotate, and stable detection is ensured.

Referring to fig. 2, in an embodiment of the present invention, a gap is formed between the hydraulic pipe 21 and an inner wall of the measured pipe 10.

That is, the end of the hydraulic branch pipe 212 is spaced from the inner wall of the pipe 10 to be tested when it is disposed toward the inner wall of the pipe 10 to be tested, so as to avoid damage to the inner wall of the pipe 10 to be tested when the detecting device is put in.

Further, can overlap at the tip of this hydraulic branch pipe 212 and establish the rubber packing ring, when putting into this detection device, can avoid causing the damage to the pipeline inner wall that is surveyed on the one hand, on the other hand guarantees this detection device's stable placing, is difficult for empting.

Referring to fig. 3, in an embodiment of the present invention, in order to fix the piezoelectric sensor 222, the piston head 221 has an embedded groove facing away from the hydraulic manifold 211, the piezoelectric sensor 222 is embedded in the embedded groove, and a surface of the piezoelectric sensor 222 facing away from the embedded groove passes over a surface of the piston head 221 facing away from the hydraulic manifold 211.

The piezoelectric sensor 222 can be embedded in the embedded groove in a sticking or buckling connection manner, so that fixation is realized.

Referring to fig. 1, the present invention further provides a method for detecting a damage of a built-in pipeline, including any one of the above-mentioned built-in pipeline damage detecting systems, where the number of the pipeline damage detecting devices is two, and the two pipeline damage detecting devices are a first pipeline damage detecting device 201 and a second pipeline damage detecting device 202, respectively, and the method includes the following steps:

hydraulic pressure is respectively injected into the first pipeline damage detection device 201 and the second pipeline damage detection device 202 through the liquid injection pipe 213, the hydraulic pressure enters the hydraulic branch pipe 212 through the hydraulic main pipe 211, and when the hydraulic pressure reaches a first preset value, the piezoelectric sensor 222 is pressed to be tightly attached to the inner wall of the pipeline 10 to be detected;

the piezoelectric sensors 222 of the first pipeline damage detection device 201 and the second pipeline damage detection device 202 transmit the acquired first signal set to the terminal;

the terminal obtains damage state parameters of the detected pipeline 10 according to the first signal set, and when a damage point exists in the detected pipeline 10, the terminal judges the position of the damage point of the detected pipeline 10 according to the first signal set;

when the position of the damage point cannot be judged according to the first signal set, unloading the hydraulic pressure, moving the first pipeline damage detection device 201 and/or the second pipeline damage detection device 202 along the axial direction of the detected pipeline 10, then loading the hydraulic pressure to reach a first preset value, and pressing the piezoelectric sensor 222 to be tightly attached to the inner wall of the detected pipeline 10;

the piezoelectric sensor 222 transmits the second set of acquired signals to the terminal;

and the terminal obtains the damage state parameters of the detected pipeline 10 according to the first signal set and the second signal set and judges the position of the damage point of the detected pipeline 10.

The terminal may be a computer terminal, which is connected to the piezoelectric sensor 222 in a telecommunication manner, such as a wired connection or a wireless connection, and will not be described in detail.

The first preset value is determined according to the type of the piezoelectric sensor 222 and the frequency of the excitation signal, so that the piezoelectric sensor 222 does not resonate under the excitation of the preset frequency signal, and can stably work.

In the first signal set, when the first pipeline damage detection device 201 detects a damage point, if the second pipeline damage detection device 202 does not detect the damage point, it cannot be determined that the direction of the damage point is located on the left side or the right side of the first pipeline damage detection device 201.

If the second pipeline damage detection device 202 does not detect the damage point, the second pipeline damage detection device needs to be moved, the signal set during moving is a second signal set, when the second pipeline damage detection device 202 is moved, the second pipeline damage detection device moves towards the direction close to the first pipeline damage detection device 201, when the second pipeline damage detection device 202 detects the damage point, it can be determined that the damage point is located on one side of the first pipeline damage detection device 201 close to the second pipeline damage detection device 202, when the second pipeline damage detection device 202 moves to the nearest distance from the first pipeline damage detection device 201, the damage point is still not detected, it can be determined that the second pipeline damage detection device 201 is located on one side of the first pipeline damage detection device 201 away from the second pipeline damage detection device 202.

Similarly, the position of the damage point detected by the second pipeline damage detection device 202 in the first signal set may be determined, which is not described herein again.

In this way, the location of the damage point can be ascertained according to the above method for ease of maintenance.

In addition, in an embodiment of the present invention, the pipeline damage detecting device further includes a driving structure, and the driving structure is configured to drive the piezoelectric sensor 222 to rotate.

Specifically, the driving structure includes a piston rod and a motor, one end of the piston rod is fixedly connected to the piston head 221, the other end of the piston rod is connected to a rotating shaft of the motor, and the piston rod is disposed in the hydraulic branch pipe 212 and extends along the length direction of the hydraulic branch pipe 212.

Therefore, the piston rod can be driven to rotate by the motor rotating shaft, the piston rod drives the piston head 221 to rotate by the rotation of the piston rod, and the piezoelectric sensor 222 is fixed on the piston head 221, so that the piezoelectric sensor 222 can be driven to rotate.

In addition, the hydraulic manifold 211 has a through hole, the other end of the piston rod passes through the through hole, the inner wall of the through hole is provided with a sealing ring, the sealing ring is arranged around the periphery of the piston rod, and the motor is located outside the hydraulic pipe 21.

The motor is arranged outside the hydraulic pipe 21, so that the motor can be prevented from being soaked, and the stable driving of the driving structure is ensured.

In this way, the direction in which the piezoelectric sensor 222 is attached to the pipe 10 to be measured can be changed by the driving structure, and the range of detecting damage to the pipe can be increased.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.