JP2016042043A - Outer shell corrosion inspection apparatus and outer shell corrosion inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer shell corrosion inspection apparatus and an outer shell corrosion inspection method capable of easily inspecting for corrosion accumulated on a thick wall part of an outer shell of a piping based on ultrasonic waves which are emitted in a circumferential direction of the piping and which is reflected several times at the inner surface and outer surface of the thick wall part.SOLUTION: The outer shell corrosion inspection apparatus 10 emits ultrasonic waves in a circumferential direction of a piping 70 and inspects for accumulation of corrosion on a thick wall part 71 of the outer shell 74 based on the ultrasonic waves which are reflected by the inner surface 73 of the thick wall part 71 of the piping 70. The outer shell corrosion inspection apparatus 10 includes: a wedge 13 having a contact face 13a which comes into surface contact with the outer surface of a cylindrical surface of the thick wall part; and an ultrasonic waves array sensor 11 which is provided to the wedge 13 so as not to make relative movement and transmits and receives the ultrasonic waves reflected by the inner surface 73 of the thick wall part 71 while proceeding in a circumferential direction. The contact face 13a of the wedge 13 is brought into contact with the cylindrical outer surface 72 of the thick wall part 71 in the circumferential direction so that the ultrasonic waves irradiate a wide range on the thick wall part 71 on the piping 70.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an external corrosion inspection apparatus that inspects external corrosion of a thick part of a pipe based on ultrasonic waves that are irradiated with ultrasonic waves in the circumferential direction of the pipe and repeatedly reflected the inner surface and the outer surface of the thick part a plurality of times. And an external corrosion inspection method.

Generally, piping that constitutes a plant such as a petrochemical apparatus is arranged outdoors. For this reason, the outer surface of the thick part of the pipe is corroded by rainwater or the like, and the outer surface corrosion that the thickness of the thick part is reduced tends to occur. And the iron oxide which generate | occur | produces at the time of the outer surface corrosion will cover the thinned outer surface in layers.
When pipes are inspected, such covered iron oxide is mechanically removed, and then the depth of corrosion visually is measured. At this time, if the corrosion is deep, the removal of iron oxide may form a through hole in the pipe, which may cause pipe leakage.
Therefore, when inspecting external corrosion with a large amount of iron oxide covering, nondestructive inspection using radiation or ultrasonic waves is performed as a preliminary inspection. As a nondestructive inspection using ultrasonic waves, a nondestructive inspection apparatus using ultrasonic waves described in Patent Document 1 is known.

  However, pipes are often installed in narrow spaces. For this reason, when performing nondestructive inspection by radiation, it may be difficult to install a nondestructive inspection apparatus in piping in consideration of exposure of a radiation inspector. In addition, when performing an ultrasonic inspection, the circumference of a pipe to be inspected is narrow, and it may be difficult to install a large ultrasonic device in the pipe.

  In particular, since the nondestructive inspection apparatus described in Patent Document 1 needs to attach a guide rail for Rayleigh waves to a pipe, the shape and size of the pipe that can be inspected are limited (for example, a small-diameter pipe or a complicated pipe). Inspection is not possible with piping of a simple shape).

JP 2011-27571 A

  Accordingly, an object of the present invention is to easily irradiate ultrasonic waves from the narrow mounting range in the circumferential direction of the pipe, and based on the ultrasonic waves repeatedly reflected a plurality of times on the inner surface and outer surface of the thick portion, An object of the present invention is to provide an outer surface corrosion inspection apparatus and an outer surface corrosion inspection method for inspecting an outer surface corrosion of a thick part.

The present invention provides the following [1] to [4].
[1] An outer surface for inspecting the outer surface corrosion of the thick part of the pipe based on the ultrasonic wave which is irradiated with ultrasonic waves in the circumferential direction of the pipe and the inner surface and the outer surface of the thick part of the pipe are repeatedly reflected a plurality of times. A corrosion inspection device,
A wedge having a contact surface in surface contact with the outer surface of the cylindrical side surface of the thick part;
An ultrasonic array sensor that is relatively immovable on the wedge, proceeds in the circumferential direction, and transmits and receives ultrasonic waves that repeatedly reflect the inner surface and the outer surface of the thick portion multiple times;
An ultrasonic flaw detector that transmits and receives the ultrasonic waves by a phased array method with the ultrasonic array sensor;
Based on transmission / reception information transmitted and received by the ultrasonic flaw detection unit, an outer surface thinning imaging unit that images a reflection echo image of an outer surface thinning state of the thick part,
A display unit for displaying the reflected echo image,
The contact surface of the wedge is in contact with the outer surface of the cylindrical side surface of the thick part in the circumferential direction without gap so that the ultrasonic wave irradiates a wide range of the thick part of the pipe. Inspection device.

[2] The outer surface thinning imaging unit calculates the position of the inner surface of the thick part reflected by the ultrasonic wave, and the display unit displays the calculated position of the inner surface together with the reflected echo image. [1] The external corrosion inspection apparatus according to [1].

[3] The external corrosion inspection apparatus according to any one of [1] or [2], further including a storage unit that stores a predetermined reflection echo image among the reflection echo images.

[4] An external corrosion inspection method using the external corrosion inspection apparatus according to any one of [1] to [3].

  ADVANTAGE OF THE INVENTION According to this invention, the external corrosion inspection apparatus and external corrosion inspection method which test | inspect objectively external corrosion of the thick part of piping can be provided.

It is a block diagram which shows the structure of the external surface corrosion inspection apparatus which concerns on this invention. It is a flowchart of the outer surface corrosion inspection apparatus shown in FIG. It is a schematic diagram explaining the advance preparation of the outer surface corrosion inspection apparatus shown in FIG. It is a schematic diagram of the image of the display part of the outer surface corrosion inspection apparatus shown in FIG. It is a schematic diagram explaining the test | inspection state of the external corrosion test | inspection apparatus following FIG. It is a schematic diagram of the image of the display part of the outer surface corrosion inspection apparatus shown in FIG.

As shown in FIG. 1, the outer surface corrosion inspection apparatus 10 according to the present invention irradiates ultrasonic waves in the circumferential direction of a pipe 70, and converts the inner surface 73 and the outer surface 72 of the thick portion 71 into ultrasonic waves that are repeatedly reflected a plurality of times. Based on this, the outer surface corrosion 74 of the thick portion 71 of the pipe 70 is inspected.
The outer surface corrosion inspection apparatus 10 transmits and receives an ultrasonic wave reflected by the inner surface 73 of the thick part 71 while being in contact with the outer surface 72 of the thick part 71, and the ultrasonic array sensor 11. And the outer surface corrosion inspection main body 20 including the ultrasonic flaw detection unit 30 that inspects the outer surface corrosion 74 of the thick portion 71.
The ultrasonic array sensor 11 and the outer surface corrosion inspection main body 20 are connected by a cable 12. The ultrasonic array sensor 11 is composed of a plurality of transducers (elements). The outer surface corrosion inspection main body 20 includes an ultrasonic flaw detector 30, an outer surface thinning imaging unit 40, a storage unit 50, and a display unit 60.

The wedge 13 has a contact surface 13 a that comes into surface contact with the outer surface 72 of the cylindrical side surface of the thick portion 71.
The contact surface 13 a is in contact with the outer surface 72 of the cylindrical side surface of the thick portion 71 without a gap in the circumferential direction so that the ultrasonic wave irradiates a wide range of the thick portion 71 of the pipe 70. Specifically, the curved shape of the contact surface 13a is such that the contact surface 13a and the outer surface 72 are in surface contact, and the ultrasonic wave of the ultrasonic array sensor 11 with respect to the center O of the pipe 70 is extensively applied to the thick part 71 of the pipe. It has substantially the same shape as the outer surface 72 so as to be irradiated.

The ultrasonic flaw detector 30 transmits and receives ultrasonic waves reflected by the inner surface 73 of the thick portion 71. In other words, the ultrasonic flaw detector 30 is a device that performs transmission and reception of ultrasonic waves by the ultrasonic array sensor 11 using the phased array method.
The ultrasonic wave transmitted from the ultrasonic flaw detector 30 enters the thick portion 71 via the contact surface 13 a of the wedge 13, and the ultrasonic flaw detector 30 transmits the ultrasonic wave reflected by the outer surface corrosion 74 to the contact surface 13 a of the wedge 13. Receive via.
The ultrasonic flaw detector 30 includes a transmission circuit 31, a reception circuit 32, an A / D conversion circuit 33, and a delay circuit 34. The transmission circuit 31 transmits an input signal to the ultrasonic array sensor 11. The receiving circuit 32 receives an output signal from the ultrasonic array sensor 11. The A / D conversion circuit 33 converts an ultrasonic output signal from an analog signal to a digital signal. The delay circuit 34 controls the transmission time of the ultrasonic signal from the transducers constituting the ultrasonic array sensor 11. Specifically, the delay circuit 34 controls the timing (delay time) for applying a voltage to the transducers (elements) constituting the ultrasonic array sensor 11.

  The outer surface thinning imaging unit 40 reflects the situation of the outer surface corrosion 74 of the thick part 71 on the basis of the reflection echo image (reflection echo image) obtained by imaging the situation of the outer surface corrosion 74 of the thick part 71. To image. Based on the delay time output to the delay circuit 34 and the reception information from the reception circuit 32 via the A / D conversion circuit 33, the outer surface thinning imaging unit 40 is a thick part of the pipe 70 to be inspected. A reflection echo image due to the external surface corrosion is calculated to make the inspector determine whether or not the external surface 72 of the surface 71 has external surface corrosion, and the calculated reflection echo image is displayed on the display unit 60. The reflected echo image can be obtained by a known method. Further, the outer surface thinning imaging unit 40 displays the ultrasonic waves reflected from the outer surface corrosion 74.

  The storage unit 50 is a memory that stores a predetermined reflected echo image among the reflected echo images of the outer surface thinning imaging unit 40. The reflected echo image stored in the storage unit 50 is, for example, a reflected echo image when the ultrasonic array sensor 11 is inspecting the deepest state of external corrosion.

  The display unit 60 is a monitor that displays a reflected echo image.

  The ultrasonic array sensor 11 has a plurality of transducers (elements) and a contact surface that is in sliding contact with the outer surface 72 of the thick portion 71 that is the inspection target site. In the phased array method, when an electric signal is sent to each transducer, the transmission time of the applied voltage is controlled by the delay circuit 34, and the superposition position of the phase of the ultrasonic wave generated from each transducer is controlled, thereby transmitting the transmission angle. Sector scanning is performed. Here, the control of the ultrasonic beam form is performed by setting a delay time. In general, since the inspection target part is made of a single material, the ultrasonic propagation time between the beam focusing point and each transducer is calculated as (linear geometric path) / (material sound velocity) and propagates to each transducer. The time difference can be used to determine the delay time of the array sensor. In addition, by using the delay time at this time and synthesizing the received wave, the inspection result can be displayed two-dimensionally.

With reference to FIG. 2 to FIG. 6, an external corrosion inspection method using the external corrosion inspection apparatus 10 will be described.
The external corrosion inspection method using the external corrosion inspection apparatus 10 performs a flaw detection test according to the procedure shown in FIG.

  First, as shown in FIGS. 3A and 3B, the wedge 13 to which the ultrasonic array sensor 11 is attached so that the contact surface 13 a comes into surface contact with the outer surface 72 at a position 75 where the outer surface corrosion 74 does not exist. Is in contact with the outer surface 72 of the thick portion 71 of the pipe 70 to be inspected, and flaw detection is performed by the phased array method (sector scan) (step ST01). At this time, as shown in FIG. 4, it is confirmed that the reflected echo image is not displayed on the display unit 60, and when the reflected echo image is displayed on the display unit 60, the reflected echo image is not displayed. Thus, the display unit 60 is adjusted (step ST01). For adjustment of the display unit 60, it is preferable to use a test piece.

  Next, whether or not there is a reflection echo due to external corrosion is determined by scanning in the axial direction f while viewing the reflection echo image (FIG. 4) displayed on the display unit 60 (step ST02). At this time, if there is no reflection echo due to external corrosion, it is determined that there is no external corrosion or slight external corrosion with an erosion depth of less than 0.5 mmd (step ST13). On the other hand, when there is a reflection echo due to outer surface corrosion, the outer surface thinning imaging unit 40 determines that there is outer surface corrosion with an erosion depth of 0.5 mmd or more (step ST05).

  Next, as shown in FIGS. 5A and 5B, when it is determined that there is external corrosion having an erosion depth of 0.5 mmd or more, the wedge 13 to which the ultrasonic array sensor 11 is attached is attached to the external surface 72. While making contact, the outer surface corrosion 74 is scanned in the axial direction f to find a position having the maximum reflection intensity (step ST07). Thereby, a reflection echo image as shown in FIG. 6 is displayed on the display unit 60.

Next, the outer surface corrosion 74 is measured at the position where the erosion depth becomes maximum from the reflected echo image continuously displayed on the display unit 60 when the ultrasonic array sensor 11 is moved in the axial direction f ( In step ST09, the reflected echo image at that time is stored in the storage unit 50 (step ST11).
The flaw detection test is completed by the above procedure.

Thus, the outer surface corrosion inspection apparatus 10 can display the degree of outer surface corrosion of the thick portion 71 of the pipe 70 on the display unit and inspect the outer surface corrosion of the pipe.
Further, the outer surface corrosion inspection apparatus 10 includes an ultrasonic array sensor 11 integrally attached to the wedge 13, an outer surface corrosion inspection main body 20 including an ultrasonic flaw detection unit 30 that inspects the outer surface corrosion 74 of the thick portion 71, and Since it is only equipped with, inspection of piping arranged in a narrow space can also be performed.

DESCRIPTION OF SYMBOLS 10 Outer surface corrosion inspection apparatus 11 Ultrasonic array sensor 12 Cable 13 Wedge 13a Wedge contact surface 14 Ultrasonic propagation range 20 Outer surface corrosion inspection main body 30 Ultrasonic flaw detection unit 31 Transmission circuit 32 Reception circuit 33 Conversion circuit 34 Delay circuit 40 Outer surface thinning Imaging section 50 Storage section 60 Display section 70 Piping 71 Thick section 72 Piping outer surface 73 Piping inner surface 74 External corrosion 75 Position where no external corrosion exists

Claims (4)

An external corrosion inspection apparatus that inspects external corrosion of the thick part of the pipe based on ultrasonic waves that are irradiated with ultrasonic waves in the circumferential direction of the pipe and the inner surface and outer surface of the thick part of the pipe are repeatedly reflected a plurality of times. Because
A wedge having a contact surface in surface contact with the outer surface of the cylindrical side surface of the thick part;
An ultrasonic array sensor that is relatively immovable on the wedge, proceeds in the circumferential direction, and transmits and receives ultrasonic waves that repeatedly reflect the inner surface and the outer surface of the thick portion multiple times;
An ultrasonic flaw detector that transmits and receives the ultrasonic waves by a phased array method with the ultrasonic array sensor;
Based on transmission / reception information transmitted and received by the ultrasonic flaw detection unit, an outer surface thinning imaging unit that images a reflection echo image of an outer surface thinning state of the thick part,
A display unit for displaying the reflected echo image,
The contact surface of the wedge contacts the outer surface of the cylindrical side surface of the thick portion in the circumferential direction without gap so that the ultrasonic wave irradiates a wide range of the thick portion of the pipe. Inspection device. The outer surface thinning imaging unit calculates the position of the inner surface of the thick part reflected by the ultrasonic wave,
The outer surface corrosion inspection apparatus according to claim 1, wherein the display unit displays the calculated position of the inner surface together with the reflected echo image.   Furthermore, the external surface corrosion inspection apparatus of Claim 1 or 2 provided with the memory | storage part which memorize | stores a predetermined reflective echo image among the said reflective echo images.   An external corrosion inspection method using the external corrosion inspection apparatus according to claim 1.

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