Phased array ultrasonic water wedge apparatus

ES 2 284 339 B2

DESCRIPTION

In-phase directional ultrasonic probe assembly.

Background of the invention

The present invention relates generally to the ultrasonic inspection of heterogeneous metal welds, particularly, to the ultrasonic inspection of heterogeneous metal welds with phase directional transducers and more particularly to a phase directional ultrasonic probe assembly.

Nuclear reactor pipe welds, for example, are examined with ultrasonic transducers, using longitudinal waves with 45 ° and 60 ° angles of refraction. These angles are established as a “norm”, based on welding configurations, ultrasonic theory, and practical experience. Pipes are scanned in four directions to fully examine the volume of the weld, making this a very time-consuming task. Sometimes problems are experienced with the manipulator assembly that provides the ultrasonic transducers to the weld and, more seriously, with the contact between the transducers and the sample being examined. If continuous contact is not maintained between the transducer and the pipeline, the collected scan data will be incorrect, and this may result in the need for time-consuming new scans or missed faulty detections.

Phased directional ultrasonic probes have been designed to increase the examination efficiency of conventional ultrasonic examination techniques by electronically directing the ultrasonic beam through a given range of angles. One of the major problems still experienced is contact between the in-phase directional ultrasonic transducer and the sample being examined. Complex suspension mechanisms that apply downward pressure on the transducers have been used to try to overcome this problem. However, other issues such as improper scanner settings and irregularities in the pipe surface can affect the accuracy of the inspection.

Brief description of the invention

In one aspect, a phase directional ultrasonic probe assembly is provided that includes a housing and a phase directional transducer located within the housing. The box includes a first side wall and an opposite second side wall, and a first end wall and an opposite second end wall. The first and second sidewalls and the first and second endwalls delimit the cavity of the box, within which the in-phase directional transducer is placed. The first and second side walls each have an internal surface that includes a plurality of ridges.

In another aspect, a phase directional ultrasonic probe assembly is provided that includes a housing and a phase directional transducer pivotally mounted within the housing. The in-phase directional transducer includes a plurality of elements. The box includes a first side wall and an opposite second side wall, and a first end wall and an opposite second end wall. The first and second sidewalls and the first and second endwalls delimit the cavity of the box, within which the in-phase directional transducer is placed. The first and second side walls each have an internal surface that includes a plurality of ridges.

In another aspect, a method is provided for inspecting a portion of the weld on a metal object, using a phase directional ultrasonic probe assembly. The probe assembly includes a housing and a phase directional transducer pivotally mounted within the housing. The box includes a first side wall and an opposite second side wall, and a first end wall and an opposite second end wall. The first and second sidewalls and the first and second endwalls delimit the cavity of the box, within which the in-phase directional transducer is placed. The first and second side walls each have an internal surface that includes a plurality of ridges. The procedure includes placing the directional ultrasonic probe assembly in phase next to the outer surface of the portion of the weld to be inspected, adding a fluid to the cavity of the box, and sweeping the weld.

Brief description of the drawings

Figure 1 is a perspective illustration of an in-phase directional ultrasonic probe assembly in accordance with one embodiment of the present invention.

Figure 2 is a sectional illustration of a side wall of the in-phase directional ultrasonic probe assembly depicted in Figure 1.

Figure 3 is a sectional illustration of an end wall of the in-phase directional ultrasonic probe assembly depicted in Figure 1.

Figure 4 is a side illustration of the in-phase directional ultrasonic probe assembly depicted in Figure 1 mounted on a pipe.

ES 2 284 339 B2

Figure 5 is a schematic illustration of the transducer. in-phase directional ultrasonic depicted in Figure

1.

Detailed description of the invention

Next, an in-phase directional ultrasonic probe assembly including a housing and an in-phase directional transducer located within the housing will be described in detail. The box includes opposing side walls having a plurality of "saw tooth" shaped projections, and opposing end walls each having at least one "saw tooth" or triangle projection. The box maintains the directional ultrasonic transducer in phase in a supportive vertical water column. The water fills the volume between the bottom of the transducer and the material being examined, and allows the ultrasonic waves to travel directly from the probe to the material, without any break in contact. The sound leaves the transducer at a predetermined angle and travels through the water until it comes into contact with the material, then undergoing a change in velocity. The change in speed causes refraction of sound as it penetrates the material, allowing inspection of the weld volume using the predetermined angle. To minimize the amount of noise introduced into the assembly, the walls of the box are designed to absorb or scatter quasi-surface reflections, thereby improving resolution. Circumferential and axial defects can be recognized. Circumferential defects are detected when the transducer is perpendicular to the longitudinal axis of the pipe. To detect axial defects, the transducer is rotated along the longitudinal axis of the pipe.

With reference to the drawings, Figure 1 is a perspective illustration of a phase directional ultrasonic probe assembly 10 according to an embodiment of the present invention. The probe assembly includes a box 12 and a phase directional ultrasonic transducer 14 pivotally mounted within the box 12. The box 12 is substantially rectangular in shape and includes a first side wall 16, an opposite second side wall 18, a first end wall 20, and an opposite second end wall 22. Side walls 16 and 18 and end walls 20 and 22 delimit a cavity 24, inside which the transducer 14 is mounted.

Pivots 26 and 28 extend through end walls 18 and 20, respectively, allowing for pivotal mounting of transducer 14 within housing 12. Transducer 14 has an angle adjustment block 30 attached to one end that engages interfaces with an angle selection element 32 coupled to box 12. In the exemplary embodiment, the angle selection element 32 includes an arcuate portion 34 that mates with an arcuate end 36 of the angle adjustment block 30. An adjustment screw 38 of the angle selection element sets the angle adjustment block 30 in place, thereby setting the desired angle of transducer 14.

The cavity of the box 24 is filled with a liquid. In the exemplary embodiment, the liquid is water and, in another embodiment, the liquid is a combination of liquids that facilitates the transmission and reception of beams of ultrasonic sound. The box 12 has a fluid inlet 40 to allow the cavity 24 of the box to be filled with fluid. The box 12 also includes at least one air expulsion opening 42 (two of these being shown) to extract air accumulated in the cavity 24 during the filling of the cavity with fluid.

A first flexible membrane seal 44 covers the area between transducer 14 and side walls 16 and 18 to maintain fluid within cavity 24 of the box. A second seal 46 seals the bottom of the box 12 to the object being inspected. The seal 46 of one embodiment is a seal membrane having at least one slit or opening to allow fluid to flow through the cavity 24 of the box, while maintaining a volume of fluid in the cavity 24 of the box. that occupies the volume of the cavity 24 comprised between the bottom of the transducer 14 and the object being examined. In an alternative embodiment, the seal 46 is comprised of a resilient material that is disposed around the bottom edge of the box 12 to provide a seal, such that water will not be able to escape from the cavity 24 of the box. Housing 12 also includes at least one attachment member for tool manipulator 48, whereby probe assembly 10 is coupled to a tool manipulator (not shown).

Figure 2 is a sectional illustration of the side wall 16 of the phase directional ultrasonic probe assembly 10, and Figure 3 is a sectional illustration of the end wall 20. Also referring to Figures 2 and 3, the side walls 16 and 18 include a plurality of projections 50 projecting from internal surfaces 52 and 54, respectively. End walls 20 and 22 include at least one shoulder 56 projecting from internal surfaces 58 and 60, respectively. In the exemplary embodiment, the projections 50 and 56 have a triangular or "sawtooth" shape. In alternative embodiments, the ribs 50 and 56 may take other shapes (eg, semicircular, elliptical, or any other shape) that reduce the noise generated by the reflection of sound waves on the walls of the box 12.

Figure 4 is a schematic illustration of the phase directional transducer probe assembly 10 mounted on pipe 61, and Figure 5 is a schematic illustration of the phase 12 directional ultrasonic transducer. Referring also to Figures 4 and 5, the transducer 12 includes a plurality of elements 62 that emit an ultrasonic beam 64. An important aspect of using the probe assembly is the ability to dynamically synthesize the ultrasonic beam 64 and create a "virtual probe" of any angle within the overall beam spread of an individual element 62. In operation, the beam 64 is created firing each element in sequence

ES 2 284 339 B2 to create a wavefront 66 that follows the desired angle 68. The angle 68 is selected and set by the angle selection element 32 and the angle adjustment block 30. This "virtual probe" can also "Sweep" weld 70 from pipe 61, firing groups of elements from a large array. This effect can be used to dynamically focus or "electrically steer" the ultrasonic beam 64, by selecting the probe firing order and pulse delays. This can be switched from pulse to pulse to effectively "sweep" a focal point across the weld 70. Beam orientation and dynamic focus can be combined to allow the resulting beam 64 to focus and acquire the desired angle in predetermined increments. Phase 14 directional ultrasonic transducers are available from Krautkramer Ultrasonic Systems Group of Agfa NDT, Inc., Lewistown, Pennsylvania.

Referring to Figure 5, the basic parameters of the transducer 14 are the frequency, the aperture A, the size of the X elements, the width of the Y elements, the pitch P and the number of elements 62. The appropriate frequency for the The type of material and the thickness of the weld 70 of a pipe 61 located in a nuclear reactor is between 1.0 and 5.0 MHz. However, it is possible to use other transducer frequencies for pipes and pipe welds manufactured with other materials.

The pitch of the elements P is determined by calculating the acoustic aperture A necessary to focus the beam 64 on the necessary sound path and dividing this value by the total number of elements 62 and the amount of orientation required to create the desired angles. The size X of the elements 62 is set as the maximum possible pitch. The width Y of elements 62 is determined by calculating the effective diameter so that a six-inch near field provides the smallest beam profile in the Y-plane. Physical constraints on the scan surface must also be taken into account when considering determine the values ​​of the basic parameters of the transducer 14.

Referring again to Figure 4, volume 72 of beam 64 being examined includes weld 70 and tubing 61 extending from outer surface 74 toward inner surface 76. Like transducer 14 can be oriented at a plurality of angles 68, as noted above, beam 64 can be oriented or guided at a plurality of angles. In one embodiment, the substantially axial path of beam 64 through weld 70 may be oriented in a linear path with the same orientation as weld 70. In another embodiment, the substantially axial path of beam 64 through weld 70 may be oriented along a linear path perpendicular to the orientation of the weld 70, in predetermined increments. In another embodiment, beam 64 can be oriented along a substantially circular path through weld 70.

Although the present invention has been described in terms of various concrete embodiments, it will be understood by those skilled in the art that the present invention can be practiced with modifications that are within the spirit and scope of the claims.

Component list in-phase directional ultrasonic probe assembly 10 box 12 in-phase directional ultrasonic transducer 14 first side wall 16 second side wall 18 first end wall 20 second end wall 22 box cavity 24 pivots 26 and 28 angle adjustment block 30 angle selection element 32 arcuate part 34 arc-shaped end 36 adjusting screw 38

ES 2 284 339 B2 fluid inlet 40 air expulsion opening 42 first flexible membrane seal 44 second seal 46 connecting element with tool manipulator 48 projections 50 internal surfaces of side walls 52 and 54 projection 56 internal surfaces of walls terminals 58 and 60 pipe 61 elements 62 ultrasonic beam 64 wave front 66 angle 68 weld 70 volume 72 external surface 74 internal surface 76.