JP2015025704A - Pig for corrosion inspection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pig for corrosion inspection for inspecting corrosion in a pipeline even in a pipeline formed of a pipe whose inner diameter is limited.SOLUTION: The pig for corrosion inspection comprises: a pig 2 for power supply, mounting a power supply 22 thereon; a pig 3 for a first sensor, having a first sensor 33 for inspecting corrosion in a range of an inner wall to an outer wall of a pipe 101; a second sensor 43 for inspecting corrosion in the inner wall of the pipe 101 and being driven by power supplied from the power supply 22; and a controller having a control part 54 for controlling at least drive of the first and second sensors 33 and 43, and a storage part 55 for storing inspection results inspected by the first and second sensors 33 and 43. The second sensor 43 or the controller is mounted on at least one of different pigs when there are different pigs different from the pig 2 for power supply or the pig 3 for first sensor, and the pig 2 for power supply is disposed on a front position.

Description

  The present invention relates to a corrosion inspection pig, and more particularly to a corrosion inspection pig that moves under the pressure of a fluid flowing in a pipeline.

  Conventionally, there has been proposed a corrosion inspection pig that inspects pipe corrosion by moving in a pipeline. There are two types of corrosion inspection pigs: one that moves in the pipeline with no fluid flowing in the pipeline (see Patent Documents 1 and 2) and the other in the pipeline with fluid flowing in the pipeline. There are moving objects (fluid-moving type corrosion inspection pigs).

  In a fluid movement type corrosion inspection pig, it moves with the pressure of the fluid flowing in the pipeline. Therefore, in such a corrosion inspection pig, a sensor for inspecting the pipeline, a control unit for controlling the sensor, a storage unit for storing the inspection result, a power source for supplying power to these, and the like are moved in the pipeline. Will be.

JP 2003-270210 A JP 2011-27592 A

  By the way, the specifications of pipes differ depending on the pressure of the flowing fluid. For example, in a city gas pipeline in Japan, a high-pressure pipe used for high-pressure (eg, 1.0 MPa or more) gas, and a medium-pressure pipe used for medium-pressure (eg, 0.3 MPa or more and 1.0 MPa or less) gas Then, the pipe diameter of the medium pressure pipe tends to be smaller than that of the high pressure pipe.

  Here, since the corrosion inspection pig is for inspecting the corrosion of the pipe from the inside of the pipeline, a sensor is disposed in the vicinity of the inner wall of the pipe. In other words, the outer diameter of the corrosion inspection pig approximates the inner diameter of the pipe. Until now, fluid-transfer type corrosion inspection pigs were often applied to high-pressure pipes. However, when used for pipes with a limited inner diameter, such as medium-pressure pipes, it is difficult to implement each function. It was.

  Therefore, the present invention has been made in view of the above, and proposes a corrosion inspection pig capable of inspecting corrosion in a pipeline even in a pipeline constituted by pipes having a limited pipe inner diameter. The purpose is to do.

In order to solve the above-described problems and achieve the object, the corrosion inspection pig according to the present invention,
(1) A power supply pig mounted with a power supply, a first sensor pig driven by power from the power supply and having a first sensor for inspecting corrosion from the inner wall to the outer wall of the pipe, and driven by power from the power supply , A control having a second sensor that inspects corrosion of the inner wall of the pipe, a control unit that performs drive control of at least the first sensor and the second sensor, and a storage unit that stores the inspection results of the first sensor and the second sensor The second sensor or the control device is mounted on at least one of the different pigs when there is a pig different from the power pig or the first sensor pig, and the power pig is arranged at the head. It is characterized by.

  (2) Further, in the corrosion inspection pig of the above (1), it is preferable that the second sensor is mounted on the second sensor pig, and the control device is mounted on the control pig.

  (3) Further, in the corrosion inspection pig of the above (2), it is preferable that the control pig is disposed between the first sensor pig and the second sensor pig.

  (4) Further, in the corrosion inspection pig of the above (3), it is preferable that the power supply pig, the first sensor pig, the control pig, and the second sensor pig are arranged in this order from the top.

  (5) In the corrosion inspection pig of (1), the second sensor and the control device are preferably mounted on the power supply pig.

  (6) In the corrosion inspection pig of (1), the control device is preferably mounted on the control pig, and the second sensor is preferably mounted on the power supply pig or the control pig.

  Corrosion inspection pig according to the present invention, the equipment constituting the fluid movement type corrosion inspection pig is dispersed and mounted on each pig, and by connecting each pig in a row, the outer diameter can be reduced, the pipe inner diameter Even in a pipeline constituted by pipes limited to the above, it is possible to inspect corrosion in the pipeline. Also, among the devices that make up a fluid-moving type corrosion inspection pig on the first pig that is most impacted while moving in the pipeline, it is equipped with a device that is resistant to shock, so it is received by moving in the pipeline. There is an effect that the adverse effect due to the impact can be minimized.

FIG. 1 is a diagram illustrating a corrosion inspection pig according to the embodiment. FIG. 2 is a diagram illustrating a modification of the corrosion inspection pig according to the embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

  FIG. 1 is a diagram illustrating a corrosion inspection pig according to the embodiment. As shown in the figure, the corrosion inspection pig 1-1 according to the present embodiment moves in the pipeline 100 with the fluid R flowing in the pipeline 100. The first sensor pig 3, the second sensor pig 4, the control pig 5, the connecting portion 6, and the distance sensor 7 are configured. The pigs 2 to 5 are electrically connected by cables 8 respectively.

  The power pig 2 is equipped with a power supply 22. The power supply pig 2 includes a main body portion 21, a power supply 22, cups 23 and 24, and a roller group 25.

  The main body 21 is formed in a cylindrical shape with a metal material or the like, and both end portions in the axial direction are closed with a closing member (not shown). Note that at least one of the closing members is detachably attached to the main body 21.

  The power source 22 supplies power to the first sensor pig 3, the second sensor pig 4, the control pig 5, and the distance sensor 7. The power source 22 is housed in a sealed state inside the main body 21 and can be taken out. The power source 22 is preferably a primary battery or a secondary battery adopting an impact resistant structure, for example.

  The cups 23 and 24 give the thrust in the direction in which the fluid R flows to the corrosion test pig 1-1 by the fluid R flowing in the pipeline 100. The cups 23 and 24 are attached to the main body portion 21 with the cup 23 on the leading side and the cup 24 on the trailing side, respectively, in a state of being separated in the axial direction. The cups 23 and 24 are formed in a bowl shape with a material such as resin having elasticity. Here, the outer diameter of the cups 23 and 24 is the maximum outer diameter of the power supply pig 2, and is set according to the inner diameter of the pipe 101 in which the corrosion inspection pig 1-1 is used. The outer diameters of the cups 23 and 24 are determined based on, for example, the inner diameter of the pipe 101 and the pressure of the fluid R flowing in the pipeline 100 (hereinafter simply referred to as “fluid pressure”). It is set to such an extent that it can move within 100. Further, the outer diameter when the cups 23 and 24 are allowed to undergo elastic deformation is set to be equal to or smaller than a set minimum inner diameter set according to the inner diameter of the pipe 101. Here, the set minimum inner diameter is a change in the direction of the pipeline 100 (for example, an elbow provided in the middle, an elbow return, etc.), a projection in the pipeline 100 (for example, a plug), or the inner diameter of the pipe 101. It is determined based on the change of (for example, thickness change). In this embodiment, the set minimum inner diameter is 90% of the inner diameter of the pipe 101, for example.

  The roller group 25 allows the corrosion inspection pig 1-1 to smoothly flow in the pipeline 100 even if the direction of the pipeline 100 changes, the protrusions in the pipeline 100, or the inner diameter of the pipe 101 changes. It is for moving in the direction in which R flows. In the roller group 25, a plurality of rotatably supported rollers are arranged in the circumferential direction, and are attached to the front side of the cup 23 of the main body 21. The outer diameter of the roller group 25 is set smaller than the set minimum inner diameter.

  Here, the power supply pig 2 is arranged on the side of the corrosion inspection pig 1-1 where the fluid R flows most, that is, at the top. That is, it passes through the pipeline 100 before the first sensor pig 3, the second sensor pig 4 and the control pig 5.

  The first sensor pig 3 inspects the corrosion from the inner wall to the outer wall of the pipe 101 by the first sensor 33. The first sensor pig 3 is disposed adjacent to the rear side of the power supply pig 2, and includes a first roller group 31, a second roller group 32, and a first sensor 33.

  The first roller group 31 and the second roller group 32 move the first sensor pig 3 smoothly in the direction in which the fluid R flows in the pipeline 100, and move the first sensor pig 3 to the center in the pipeline 100. It is held near the shaft. In each roller group 31, 32, a plurality of rollers rotatably supported are arranged in the circumferential direction, with the first roller group 31 on the leading side, the second roller group 32 on the trailing side, and the first sensor 33. It is arranged on the other side. Each of the roller groups 31 and 32 is elastically supported so as to be movable inward in the radial direction of the first sensor pig 3, and the outer diameter of the first sensor pig 3 is the pipeline 100 when no external force is applied. The outer diameter is set to such an extent that the inside can be moved, and the outer diameter when allowable elastic deformation is performed is set to be equal to or smaller than the set minimum.

  The first sensor 33 is driven by electric power from the power source 22 and inspects corrosion from the inner wall to the outer wall of the pipe 101. Power is supplied to the first sensor 33 from the power source 22 of the power pig 2 via the cable 8 and is driven. The first sensor 33 magnetizes the inner wall to the outer wall of the pipe 101 to generate a magnetic flux and measures the leakage magnetic flux, and inspects the corrosion generated from the inner wall to the outer wall of the pipe 101 based on the strength of the leakage magnetic flux. Here, the method for inspecting corrosion due to leakage magnetic flux refers to a magnetic flux that leaks from a corrosion portion formed on the surface (inner wall or outer wall) of the pipe 101 by forming a closed magnetic path by magnetizing the steel constituting the pipe 101 with a magnet. Is a method of measuring. If the pipe 101 is healthy, there is no change in the cross-sectional area of the magnetic path. If the magnetic flux density inside the healthy pipe 101 (the portion from the inner wall to the outer wall) is magnetized with such a strength that the saturation density is obtained in advance, the magnetic flux does not leak from the surface of the pipe 101 to the outside. However, since the cross-sectional area of the magnetic path is reduced when the pipe 101 is thinned due to corrosion or the like, the magnetic flux (= saturation magnetic flux density × cross-sectional area) that can exist inside the pipe 101 (the portion from the inner wall to the outer wall) is reduced. The magnetic flux that can no longer enter the magnetic path leaks from the surface of the pipe 101 to the outside.

  The first sensor 33 includes a sensor group 33a and magnetizers 33b and 33c. In the sensor group 33a, a plurality of magnetic sensors composed of coils, Hall elements, and the like are arranged in the circumferential direction, and are arranged between the magnetizers 33b and 33c. Here, the sensor group 33a is set so as to be able to measure a magnetic flux component in at least one direction parallel to, perpendicular to the axis of the pipe 101, or in the tangential direction of the circumference of the pipe 101. The sensor group 33 a is driven by power from the power source 22, and an inspection result, that is, an output is transmitted to the adjacent control pig 5 via the cable 8. The magnetizers 33b and 33c are magnets arranged on the circumference, respectively. The magnetizers 33b and 33c have a brush (not shown) formed on the outer surface, and are configured to always contact the inner wall of the pipe 101 when the brush is deformed. One magnetic circuit is formed so that the polarities are different.

  The second sensor pig 4 inspects the corrosion of the inner wall of the pipe 101 by the second sensor 43. The second sensor pig 4 is arranged adjacent to the rear side of the control pig 5 and includes a first roller group 41, a second roller group 42, and a second sensor 43.

  The first roller group 41 and the second roller group 42 move the second sensor pig 4 smoothly in the direction in which the fluid R flows in the pipeline 100, and move the second sensor pig 4 to the center in the pipeline 100. It is held near the shaft. In each roller group 41, 42, a plurality of rollers rotatably supported are arranged in the circumferential direction, with the first roller group 41 on the leading side, the second roller group 42 on the trailing side, and the second sensor 43. It is arranged on the other side. Each of the roller groups 41 and 42 is elastically supported so as to be movable inward in the radial direction of the second sensor pig 4, and the outer diameter of the second sensor pig 4 when the external force is not applied is determined by the pipeline 100. It is set to such an extent that it can move inside, and the outer diameter when the allowable elastic deformation is performed is set to be equal to or smaller than the set minimum inner diameter.

  The second sensor 43 is driven by electric power from the power source 22 and inspects corrosion of the inner wall of the pipe 101. Power is supplied to the second sensor 43 from the power supply 22 of the power supply pig 2 via the cable 8 and is driven. The second sensor 43 measures the leakage magnetic flux similarly to the first sensor 33, and inspects the corrosion generated on the inner wall of the pipe 101 from the strength of the leakage magnetic flux. The second sensor 43 includes a sensor group 43a and a magnetizer 43b. In the sensor group 43a, a plurality of magnetic sensors composed of coils, Hall elements, and the like are arranged in the circumferential direction, and are arranged in the vicinity of the magnetizer 43b. Here, the sensor group 43 a is set so as to be able to measure a magnetic flux component in at least one direction parallel to, perpendicular to the axis of the pipe 101, or in the tangential direction of the circumference of the pipe 101. The sensor group 43 a is driven by power from the power source 22, and an inspection result, that is, an output is transmitted to the adjacent control pig 5 on the adjacent side via the cable 8. The magnetizer 43b is a plurality of magnets arranged on the circumference corresponding to each sensor of the sensor group 43a. Here, the magnetic force of the magnetizer 43b is set smaller than the magnetic force of the magnetizers 33b and 33c. Thereby, the sensor group 33a inspects the corrosion from the inner wall to the outer wall of the pipe 101, while the sensor group 43a inspects the corrosion of the inner wall of the pipe 101.

  The control pig 5 controls the operation of the corrosion inspection pig 1-1 and is arranged adjacent to the rear side of the first sensor pig 3, and includes a main body 51, a first roller group 52, The second roller group 53 includes a control unit 54 and a storage unit 55 that constitute a control device. That is, the control pig 5 is disposed between the first sensor pig 3 and the second sensor pig 4.

  The main body 51 is formed in a cylindrical shape from a metal material or the like, and both end portions in the axial direction are closed by a closing member (not shown). Note that at least one of the closing members is detachably attached to the main body 51.

  The first roller group 52 and the second roller group 53 move the control pig 5 smoothly in the direction in which the fluid R flows in the pipeline 100, and hold the control pig 5 in the vicinity of the central axis in the pipeline 100. It is something to be made. In each of the roller groups 52 and 53, a plurality of rotatably supported rollers are arranged in the circumferential direction, and the first roller group 52 is arranged on the leading side and the second roller group 53 is arranged on the trailing side. Each of the roller groups 52 and 53 is elastically supported so as to be movable inward in the radial direction of the control pig 5, and the control pig 5 can move in the pipeline 100 when the external force is not applied. The outer diameter when the elastic deformation is set to the extent that is allowed is set to be equal to or smaller than the set minimum inner diameter.

  The control unit 54 constitutes a control device, controls at least the first sensor 33 and the second sensor 43, is housed in a sealed state inside the main body 51, and is taken out. Is possible. The control unit 54 is electrically connected to the power source 22, the first sensor 33, the second sensor 43, the storage unit 55, the distance sensor 7, and the like. The two sensors 43 and the distance sensor 7 are driven and controlled.

  The storage unit 55 constitutes a control device, stores inspection results from the first sensor 33 and the second sensor 43 as data, and is housed inside the main body 51 in a sealed state. , Can be taken out. Based on the command from the control unit 54, the storage unit 55 is a distance from the inspection start point that is an output of the distance sensor 7, an output value that is an inspection result by the first sensor 33, and an inspection result by the second sensor 43. Save the output value associated with.

  The connection part 6 is arrange | positioned between each pigs 2-5, respectively, and connects adjacent pigs 2-5 so that relative movement is possible. The connecting portion 6 includes a connecting main body portion 61 and joint portions 62 and 63. The connection main body 61 is provided with joint portions 62 and 63 at both ends. The joint portions 62 and 63 connect the connection main body portion 61 and the pigs 2 to 5 so as to be relatively rotatable, and in this embodiment, have at least two or more rotation axes. Accordingly, since the adjacent pigs 2 to 5 are relatively moved by the connecting portion 6 in accordance with the change in the direction of the pipeline 100, the corrosion inspection pig 1-1 changes following the change in the direction of the pipeline 100. be able to.

  The distance sensor 7 detects the distance that the corrosion inspection pig 1-1 has moved in the pipeline 100. The distance sensor 7 is provided at the tail as an example, and two distance sensors 7 are attached to the rear side of the second sensor pig 4 in this embodiment. For example, the distance sensor 7 is configured to always contact the inner wall of the pipe 101 by elastically deforming a support portion (not shown).

  Thus, in the corrosion inspection pig 1-1, the pigs 2 to 5 are arranged in the order of the power supply pig 2, the first sensor pig 3, the control pig 5, and the second sensor pig 4 from the top. Yes. In such an arrangement, the corrosion inspection pig 1-1 moves in the pipeline 100 to be inspected. Specifically, the corrosion inspection pig 1-1 moves from a launcher (not shown) that is an inspection start point provided at an arbitrary position of the pipeline 100 to a receiver (not shown) that is an inspection end point. The corrosion inspection pig 1-1 is moved from the launcher toward the receiver by receiving the fluid R flowing in the pipeline 100 by the cups 23 and 24 of the power supply pig 2. Here, the corrosion inspection pig 1-1 may be moved by the fluid R that normally flows in the pipeline 100, or the fluid R that normally flows is stopped and another fluid, for example, a compressor (not shown) in the pipeline 100 is used. And may be moved by air compressed by a compressor flowing in the pipeline 100.

  While the corrosion inspection pig 1-1 is moving in the pipeline 100, the control unit 54 drives and controls the first sensor 33, the second sensor 43, the distance sensor 7 and the like, and outputs from these to the storage unit 55. Continue to be stored as data. That is, the storage unit 55 stores the state from the inner wall to the outer wall of the pipe 101 and the state of the inner wall of the pipe 101 at an arbitrary position in the pipeline 100. Here, corrosion of the inner wall of the pipe 101 appears in the inspection results of the first sensor 33 and the second sensor 43. On the other hand, corrosion of the outer wall of the pipe 101 appears in the inspection result of the first sensor 33 but does not appear as the inspection result of the second sensor 43. Therefore, according to the corrosion inspection pig 1-1, it is possible to inspect whether corrosion has occurred on the inner wall or the outer wall of the pipe 101.

  As described above, the corrosion inspection pig 1-1 is a device constituting the corrosion inspection pig 1-1, in particular, the power source 22, the first sensor 33, the second sensor 43, the control unit 54, and the storage unit. 55 are dispersed and mounted on different pigs 2 to 5, and each of the pigs 2 to 5 is connected in a row so as to be long in the axial direction of the pipeline 100. Accordingly, since the volume of the corrosion inspection pig 1-1 is increased in the axial direction in the pipeline 100, the volume is increased in the radial direction in order to mount the equipment constituting the corrosion inspection pig 1-1. This can be suppressed. Thereby, corrosion in the pipeline can be inspected even in a pipeline constituted by a pipe having a limited pipe inner diameter.

  Further, in the corrosion inspection pig 1-1, the power supply pig mounted with the power supply 22 adopting an impact-resistant structure, not the parts causing the failure such as the movable parts and the precision parts among the pigs 2 to 5. 2 is arranged at the head. Therefore, the top of the corrosion inspection pig 1-1 may come into contact with the inner wall or protrusion of the pipe 101 due to a change in the direction of the pipeline 100, a protrusion in the pipeline 100, or a change in the inner diameter of the pipe 101. Since the most impactable head is the power supply pig 2, damage and failure of the corrosion inspection pig 1-1 can be suppressed as compared with the case where the other pigs 3 to 5 are the top. As a result, even when moving in the pipeline 100 for a long distance, corrosion can be reliably inspected by minimizing the adverse effects of impact.

  Further, since the control pig 5 is arranged between the first sensor pig 3 and the second sensor pig 4, both the outputs from the first sensor 33 and the second sensor 43 are controlled at the shortest distance. The data is input to the unit 54 and the storage unit 55. Therefore, compared with the case where other pigs are arranged between the control pig 5 and the first sensor pig 3, or between the control pig 5 and the second sensor pig 4, the first It is possible to suppress noise from being output until the output is transmitted from the sensor 33 and the second sensor 43 to the control unit 54 and the storage unit 55. Further, since the control pig 5 is disposed between the first sensor pig 3 and the second sensor pig 4, the magnetic fields generated by the first sensor 33 and the second sensor 43 are influenced by each other. Is suppressed. From these, the inspection accuracy of each of the first sensor 33 and the second sensor 43 can be improved. Further, since the control pig 5 is disposed between the first sensor pig 3 and the second sensor pig 4, the first sensor pig 3 and the second sensor pig 4, the control pig 5, It is easy to route the cable 8 that electrically connects the two.

  In addition, the control pig 5 in this embodiment should just be arrange | positioned between the pig 3 for 1st sensors, and the pig 4 for 2nd sensors. FIG. 2 is a diagram illustrating a modification of the corrosion inspection pig according to the embodiment. As shown in the figure, in the corrosion inspection pig 1-2, the pigs 2 to 5 are in order of the power supply pig 2, the second sensor pig 4, the control pig 5, and the first sensor pig 3 from the top. It may be arranged.

  In addition, although the corrosion inspection pigs 1-1 and 1-2 in the above embodiment have a four-car train, the invention is not limited to this. For example, the second sensor 43 is mounted on the power pig 2, and the three-car train except the power pig 2, the control pig 5, and the second sensor pig 4 of the first sensor pig 3 from the top is also possible. Good. For example, the second sensor 43 is mounted on the control pig 5, and the three-car train is formed by removing the power sensor pig 2, the control pig 5, and the second sensor pig 4 from the first sensor pig 3 from the top. Good. Further, for example, the second sensor 43, the control unit 54, and the storage unit 55 are mounted on the power supply pig 2, and the power supply pig 2 and the second sensor pig 4 of the first sensor pig 3 and the control piggy A two-car train without the pig 5 may be used.

  In the present embodiment, the magnetizers 33b and 33c and the magnetizer 43b are magnets, but may be permanent magnets or electromagnets. In the case of an electromagnet, the magnetizers 33 b and 33 c and the magnetizer 43 b are magnetized when power is supplied from the power supply 22. In the present embodiment, in particular, since the power supply pig 2 is disposed adjacent to the first sensor pig 3, the magnetizers 33b and 33c that require the most power among the corrosion inspection pigs 1-1. And the power source 22 can be electrically connected in the shortest distance. Therefore, loss of power supply from the power source 22 to the magnetizers 33b and 33c can be suppressed.

1-1, 1-2 Corrosion inspection pig 2 Power supply pig 22 Power supply 3 First sensor pig 33 First sensor 4 Second sensor pig 43 Second sensor 5 Control pig 54 Control unit (control device)
55 Storage unit (control device)
6 Connecting part 7 Distance sensor

Claims (6)

A power supply pig with power supply,
A first sensor pig driven by power from the power source and having a first sensor for inspecting corrosion from the inner wall to the outer wall of the pipe;
A second sensor driven by power from the power source and inspecting corrosion of the inner wall of the pipe;
A control unit having at least a control unit that performs drive control of the first sensor and the second sensor, and a storage unit that stores test results of the first sensor and the second sensor;
With
The second sensor or the control device is mounted on at least one of the different pigs when there is a different pig from the power pig or the first sensor pig,
The corrosion inspection pig, wherein the power supply pig is arranged at the head. In the corrosion inspection pig according to claim 1,
The second sensor is mounted on a second sensor pig,
The control device is a corrosion inspection pig mounted on the control pig. In the corrosion inspection pig according to claim 2,
The control pig is a corrosion inspection pig disposed between the first sensor pig and the second sensor pig. In the corrosion inspection pig according to claim 3,
Corrosion inspection pigs arranged in the order of the power supply pig, the first sensor pig, the control pig, and the second sensor pig from the top. In the corrosion inspection pig according to claim 1,
The second sensor and the control device are corrosion inspection pigs mounted on the power supply pig. In the corrosion inspection pig according to claim 1,
The control device is mounted on a control pig,
The second sensor is a corrosion inspection pig mounted on the power supply pig or the control pig.

Images