JP2001065778A - Piping inspection probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe for inspecting the inner side of a piping having a large diameter and limited access in nearly a perpendicular direction. SOLUTION: A probe 10 has a slender probe housing 13 having series flexible joints 20 in a lengthwise direction, in order to arrange them in the inner side of a piping. Plural guide arms 16, expandable in a radius direction in order to arrange the probe 10 in the piping, are fitted to the lower end of the housing 13. Moreover stabilizing weight 14 is fitted like the tail of a kite to the housing 13 adjoining the arms 16, for preventing the unstable movement of the prove 10. Furthermore, the prove 10 has a rotation drive device for rotating the arms 16 opened in the radius direction to the housing 13, and in addition, detectors 32 are arranged in the respective arm 16 end parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to an apparatus for inspection inside a generally vertical conduit or pipe, and more particularly to a diameter change inside a boiling water reactor (BWR), for example. The present invention relates to a device for detecting and determining the position of a defect detected by a jet pump diffuser in the axial and circumferential directions.

[0002]

2. Description of the Related Art Coolant piping in a BWR is periodically inspected to detect intergranular stress corrosion cracking (IGSCC) or cracking due to fatigue in the piping wall and repair the area to prevent leakage. Must be inspected. Inspection is usually performed externally because there was no way to insert the inspection probe into a jet pump diffuser assembly consisting of a jet pump mixer, diffuser and adapter. This is because the openings for accessing the internal tubing are limited and the inner diameter of the tubing varies over its length, for example, between about 3 inches and 22 inches. However, it is not possible to inspect all parts of the pipe from outside due to the effects of the support structure and other mounting members.

[0003] A much smaller diameter (about 3/4 inner diameter)
Probes have been developed to detect and locate defects inside steam generator piping. These probes have, for example, a rotatable probe head at one end of a tubular transport unit, and an electric wire passing through the transport unit connects the drive unit of the probe head and the detector to an external power supply or control device. I have. The probe head measures a change in the state of the wall and includes a detector such as an ultrasonic detector, an eddy current detector, or both.

[0004] The axial position of a wall defect can be determined by measuring the distance the probe head has been inserted into the pipe. In addition, encoders have been used to determine the circumferential position of a defect that is useful for correcting the defect as appropriate. One example of such a probe for steam generator piping is described in U.S. Pat. No. 5,760,306 (Wyatt, III) et al.
(Issued June 2, 2008). However, these probes could not be used for much larger and varying diameter jet pump diffuser assembly tubing (varying between about 3 to 22 inches in length).

[0005]

Accordingly, there is provided a new and improved apparatus for detecting a detected defect inside a pipe and determining its axial and circumferential position, and furthermore in a BWR reactor or the like. There is still a need for devices that are compatible with large, variable diameter jet pump diffusers, such as those found in US Pat.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a probe for inspecting the inside of a relatively large diameter, substantially vertical, restricted access pipe. The probe has an elongated probe housing with a lengthwise in-line flexible joint for placement in the tubing. Each flexible joint can bend about ± 5 ° in the axial direction, respectively, so that the probe can be inserted into an inspection hole with limited access.

[0007] A plurality of radially splayable guide arms are mounted at the lower end of the probe housing to position the probe in the tubing. Also, in a preferred embodiment, a stabilizing weight is mounted on the elongated housing adjacent to the plurality of guide arms to prevent unstable movement of the probe. The center of gravity of the weight is below a plane defined by the points of contact between the plurality of guide arms and the pipe wall, thereby maintaining the probe's axial position and allowing the guide arm to move as the probe moves through the pipe. The end moves a true spiral pattern. In addition, a stabilizing weight is attached to the elongated housing by a flexible joint to help access the less accessible inspection holes.

In a preferred embodiment, the probe further comprises rotational drive means for rotating a plurality of radially expandable guide arms with respect to the elongated housing. In addition, detectors are located at the end of each guide arm to more completely inspect the inside of the pipe for defects. Further, an axial drive means drives the probe along the length of the tubing, the axial drive means comprising a drive means for rotating a plurality of radially expandable guide arms relative to the elongated housing. Controlled by output.

According to one aspect of the present invention, there is provided a probe for inspecting the inside of a substantially vertical pipe having a relatively large diameter. The probe comprises: (a) an elongated housing located inside the tubing; and (b) a plurality of radially expandable guides mounted at the lower end of the probe housing for placing the probe within the tubing. And an arm.

[0010] In another aspect of the invention, a probe is provided for inspecting the inside of a relatively large diameter, substantially vertical, restricted access pipe. This probe
(A) an elongate housing having at least one flexible joint along its length so that the probe is located inside the piping; and (b) at the lower end of the probe housing for placing the probe in the piping. And a plurality of radially expandable guide arms mounted.

In yet another aspect of the invention, a probe is provided for inspecting the inside of a relatively large diameter, substantially vertical, restricted access pipe. The probe comprises: (a) an elongated housing having at least one flexible joint along its length such that the probe is located inside the pipe; and (b) a probe for placing the probe in the pipe. A plurality of radially expandable guide arms mounted at the lower end of the housing; and (c) a stabilizer mounted on the elongated housing adjacent to the plurality of guide arms to prevent unstable movement of the probe. And a weight.

[0012] The foregoing and other aspects of the invention will be apparent to those skilled in the art from the entire detailed description of the invention and the accompanying drawings.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, the same reference numerals denote the same or corresponding parts even in different drawings. In the following description, words such as “front”, “rear”, “left”, “right”, “upper”, and “lower” are used for the convenience of description, but these words are interpreted as limiting. Not be.

Referring to the entire drawings, and in particular to FIG. 1, what is shown herein is for the purpose of describing the preferred embodiment of the present invention and is not intended to limit the invention. The present invention is a remotely operated device used for ultrasonic inspection of a weld of a diffuser of a jet pump of a boiling water reactor. FIG.
As best shown in FIG. 1, a probe according to the present invention is generally designated by the numeral 10 and inspects vertical, variable inner diameter tubing. The probe 10 has a probe head 12, which has an elongated housing 13 and a plurality of guide arms 16.
The elongated housing has a plurality of flexible joints 20 arranged along its length. This allows the probe to be inserted and moved into various plumbing structures. The rotary drive motor 22 rotates the guide arm 16 along the inner circumference of the pipe, and the axial drive motor 44 arranged upstream of the probe moves the probe in the pipe length direction. The probe 10 of the preferred embodiment further includes:
A weight 14 is attached to a lower end of the probe head 12. This is for maintaining the vertical posture of the probe inside the pipe.

The elongated housing 13 has a function of protecting the drive unit from damage during use. In a preferred embodiment, the housing 13 is made of high load bearing aluminum or stainless steel. Housing 13
Has a removable portion 46 to allow access to certain portions inside the probe head, which are preferably located where repair or calibration is required.

A sheath 50 extends between the probe head 12 and the probe drive assembly 44. The sheath 50 is rigid in the torsion direction but flexible,
Acts as a shroud (side plate) that protects conductors and air pipes that extend to the probe head. Sheath 50 also functions as a medium for driving the device axially within the tubing. The probe drive assembly 44 is located at the top end of the probe outside the jet pump diffuser and allows the probe to move axially along the length of the tubing. The probe drive assembly has a take-up reel 52 and a group of pinch wheels 54 for lowering and raising the probe head along the length of the tubing, as shown in FIG. In a preferred embodiment, the pinch wheel is driven by a DC servomotor. The probe assembly further includes means for determining an axial position of the probe in the tubing, for example, an analyzer in an axial encoder. In one embodiment, the axial encoding is provided by a separate unit connected to the probe drive and the guide tube.

With a plurality of flexible joints 20 arranged along the length of the probe, the probe can be bent and installed and moved through various plumbing structures as shown in FIG. In this preferred embodiment, the three joints are in series and can move about ± 5 ° with respect to each other, which results in a total probe housing of about 30 °.
The probe can bend sufficiently over an angle and the probe can be inserted into a jet pump diffuser. In the present invention, any number of flexible joints may be provided along the length of the probe as needed for the piping being inspected.

The rotation drive motor 22 is connected to the probe head 1
2 to rotate the guide arm 16. The rotary drive motor 22 is preferably arranged near the guide arm 16. This is to prevent "wind up" which occurs when a portion of the length of the sheath 50 rotates and twists along the length of the sheath. This "entanglement"
Can adversely affect the measurement accuracy of the test. If the length of the probe to be rotated is short and the rigidity is high, the amount of “entanglement” is reduced, and the accuracy of the inspection is improved. In one preferred embodiment, rotary drive 22 is a brushless DC motor with Hall effect commutation for circumferential encoding. In one preferred embodiment, the encoder communicates between the axial drive and the rotational drive to control the rate of axial movement relative to the rotational movement of the probe head during the inspection process. This makes the axial drive dependent on the rotary drive.

A plurality of radially splayable guide arms 16 are located on the probe head. In one preferred embodiment, as shown in FIG. 1, three guide arms are spaced around the probe from each other. Each guide arm 16 has an outer arm 24 and a link arm 26. The outer arm 24 is arranged so as to be able to pass over the inner diameter of the pipe when expanded. The inside diameter of the tubing ranges from about 3 to 22 inches and may be a taper of varying diameter. A first end 33 of the outer arm is pivotally mounted with respect to the probe head, and a second end 35 is provided with a sensor assembly 32.

The linear actuator 30 has an air cylinder and a pull rod 51.
The guide arm 16 is expanded and contracted via a link arm 26 extending between the guide arm 16 and the guide arm 16. The pull rod 51
It is pushed and pulled axially by the pneumatic cylinder together with the rotary drive 22 so that the link arm pushes and pulls the guide arm, thereby opening and closing the guide arm. For example, the state where the guide arm is retracted is as shown in FIG. When the guide arm is opened as shown in FIG. 1, the pull rod is pulled in the axial direction, whereby the link arm 26 pushes the guide arm open. The pull rod 51 is pulled according to the inner diameter of the pipe, and is drawn a longer distance to open the guide arm to the fully open position, and a shorter distance to open the guide arm to a shorter distance. The air cylinder serves to keep the guide arm in contact with the pipe inner surface during the inspection process.

As shown in FIG. 6, the link arm 26 is
It is attached to the pull rod 51 by the fastener 60.
Fastener 60 has a shear surface 62 located between link arm 26 and pull rod 51. When the guide arm is stuck in the open state, the force of pulling the probe head of the probe driving mechanism 44 breaks the shear surface, whereby the guide arm is folded. Since the guide arm is no longer open after the shear plane breaks, the probe drive assembly 44 pulls the probe head axially out of the tubing, at which time the guide arm is retracted. In a preferred embodiment, the guide arm 16
The angle α between the probe arm 12 and the probe head 12 is about 90 ° or less, and the guide arm 16 is closed by the axial movement of the probe. The connection between the guide arm 16 and the pull rod 51 is such that the connecting parts are not crushed and dissipated into the pipe.

The detector assembly 32 detects the presence and length of a defect parallel to the weld and can be started from inside or outside the pipe. The scanning technique involves placing a detector assembly 32 inside the tubing, which is performed by connecting the detector pivotally with a pivot 36 to the outer arm 24, as shown in FIG. Will be

The detector assembly can vary depending on the specific parameters of the inspection process. In one embodiment, the detector assembly comprises two circumferential defect detection transducers located on the first outer arm, one circumferential defect detection transducer on the second outer arm, and a third defect detector. And two axial defect detection transducers on the outer arm of the device. Preferably, these transducers use 60 ° refracted transverse waves oriented upward, downward, clockwise, and counterclockwise. This directs the acoustic beam both perpendicular and parallel to the welding axis. In a preferred embodiment, the housing holding the transducer also has a small guide wheel that rolls on the inside surface of the tubing to reduce friction.

A detector seat 46 is positioned over the probe head to ensure that the detector assembly 32 is properly seated when the guide arm 16 is retracted as shown in FIG. When the guide arm 16 is retracted toward the central axis of the probe head, the detector assembly contacts the detector seat 46, which causes the detector to pivot, and then the detector seats in the probe head.

The weight 14 is located downstream of the retracted guide arm position. The weight provides the center of gravity for the probe below the guide arm contact point where the detector assembly contacts the inner surface of the tubing. Due to the weight 14, the probe maintains a central and axial position in the tubing to ensure that more accurate test results are obtained. Preferably, the weight is cylindrical and has a diameter equal to or less than the diameter of the housing so that it can be inserted into an opening of the same size as the opening through which the probe body can pass.

In operation, the guide arm 16 first
It is placed in a fully retracted state as shown in FIG.
The probe then passes through a plurality of handling poles 70 sequentially, through the upper end of the jet pump inlet mixer nozzle 72, and into the pipe, as shown in FIG.
The handling pole 70 provides an in-line calibration standard so that the probe can be calibrated without having to be removed from the reactor vessel. The plurality of flexible joints 20 make the probe head 12 less rigid and can be inserted into the pipe. The probe is connected to the weighted end 1
It is dropped into the pipe with 4 at the top. Probe drive assembly 44 extends the sheath so that the probe is lowered a suitable distance. When the distance is in the correct axial position, the guide arm 16 is extended and the detector assembly 32 contacts the inner pipe surface, as shown in FIG.

The probe drive assembly 44 moves the probe head 12 by the desired axial length of the tubing as the rotary drive 22 rotates the guide arm. The probe moves along the length of the pipe to spirally scan the region to be inspected. When the inspection process is completed, the guide arm is retracted to the closed position and the probe is withdrawn from the tubing.

The present invention can be applied to a remote control device used for ultrasonic inspection of welds between a jet pump mixer, a diffuser, a tail pipe, and an adapter of a boiling water reactor. With this invention, all welds of the adapter,
All welds in the tailpipe section, all welds in the diffuser, and some welds in the mixing zone can be inspected. It can also be seen that the pitch of the detector assembly can be adjusted.

From reading the above description, a person skilled in the art will perceive certain modifications and changes. For example, the air cylinder may be a piston in a housing that uses a rotary drive as the piston barrel. In this case, the force for opening the guide arm may be larger. In addition, a larger wheel may be used for the transducer housing to further reduce friction. This can also be combined with a spring loaded transducer to maintain contact between the transducer and the plumbing wall. Further, the universal joint may be modularized to further facilitate assembly and repair. The details of such modifications and improvements are omitted here, but are appropriately included in the claims.

[Brief description of the drawings]

FIG. 1 is a perspective view of a probe according to the present invention with a plurality of guide arms extended radially, with a portion of an outer housing cut away to show the interior according to the present invention.

FIG. 2 is a cutaway view of the guide arm of the probe with the guide arm closed and retracted.

FIG. 3 is a cutaway view of a probe in which a guide arm protrudes radially along an inner diameter of a pipe.

FIG. 4 is a sectional view of a probe in a state of being inserted into a pipe.

FIG. 5 is a perspective view of a probe drive assembly.

FIG. 6 is a development view of a connector for attaching a pull rod and a link arm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Probe 12 Probe head 13 Elongated housing 14 Weight 16 Plural guide arms 20 Flexible joint 24 Outer arm 26 Link arm 32 Detector assembly 36 Pivot 44 Probe drive assembly 46 Detector seat 50 Sheath 51 Pull rod 52 Take-up reel 54 Pinch wheel 60 Fastener 70 Handling pole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor John Paul Shepherd 24502 Lynchburg Townson Court, Virginia, United States 105 (72) Inventor Matthew Wayne Ares United States of America Virginia 24521 Amhurst Rodco Drive 214 F-term (reference) 2G047 AA07 AB01 AB07 AC01 BC07 DB18 GA01 GA20 GJ08 GJ11

Claims (16)

[Claims] 1. A probe for inspecting the inside of a pipe having a relatively large diameter and substantially vertical direction, comprising: (a) an elongated housing arranged inside the pipe; and (b) placing the probe inside the pipe. A plurality of radially expandable guide arms attached to a lower end of the probe housing for performing the following. 2. The probe of claim 1, further comprising a stabilizing weight mounted on said elongated housing adjacent said plurality of guide arms to prevent unstable movement of said probe. And probe. 3. The probe of claim 2, wherein the center of gravity of the weight is below a plane defined by a point of contact between an outer end of the guide arm and a wall of a pipe, thereby providing a central location for the probe. And that the axial attitude is maintained,
A probe. 4. The probe according to claim 2, wherein the stabilizing weight is attached to the elongated housing by a flexible joint such as a universal joint. 5. The probe of claim 2, wherein at least one flexible joint is provided along the length to enable placement of the probe within the pipe for inspection of restricted access pipes. A probe. 6. The probe according to claim 5, further comprising rotation driving means for rotating the plurality of guide arms capable of expanding in the radial direction with respect to the elongated housing. 7. The probe of claim 6, wherein said rotational drive means is disposed between said elongated housing and said plurality of expandable guide arms to reduce twisting errors. And probe. 8. The probe according to claim 6, wherein the rotation driving means is a brushless DC servo motor.
A probe. 9. The probe according to claim 6, further comprising an axial driving means for moving the probe along a length of the pipe. 10. The probe of claim 9, wherein the axial drive means for moving the probe along the length of the tubing includes moving the plurality of radially expandable guide arms to the elongated housing. Controlled by the output from the rotating means,
A probe. 11. The probe of claim 5, wherein each of the plurality of radially splayable guide arms attached to a lower end of the probe housing for positioning the probe in the pipe. An outer arm having one end attached to the probe housing,
A probe, comprising: a linear actuator; and a link arm attached to the actuator and the outer arm for expanding the arm. 12. The probe of claim 11, wherein at least one of said plurality of radially splayable guide arms has a detector assembly for detecting a defect in said tubing. . 13. The probe of claim 12, wherein the detector assembly is rotatable relative to an end of the guide arm near an inner surface of the tubing. 14. The probe of claim 12, wherein said detector assembly includes an NDE detector such as an ultrasonic crack detector. 15. The probe of claim 11, wherein the link arm attached to the actuator to extend the arm is attached to the actuator by a shear pin, such that the arm is in an open position. The probe, wherein the probe can be taken out in case of failure. 16. The probe of claim 15, wherein said shear pin is adapted to be captured to prevent loss of parts in the event of a failure.