Patent Application
20120006132
This invention relates to non-destructive testing and inspection (NDT/NDI) and more particularly to an NDT/NDI probe holder that facilitates the adjustment of the probe or a delay-line and probe to conveniently match the surface of test objects, such as pipes.
Many NDT/NDI applications involve inspection of target objects with un-even test surfaces, such as oil pipes, gas tanks, etc. Many NDT/NDI inspection probes require to be consistently coupled with the test surfaces at a correct angle, while the probes are slid over the test surfaces. For example, ultrasonic transducers need to be coupled to pipes being inspect at a correct angle for excitation and detection of various wave modes used for flaw detection. Coupling of the transducers is complicated by the curvature of the pipe or other test object under inspection. Another example is that eddy current sensors require constant lift-off from the inspected surface, which presents certain challenges when the sensors are slid over an un-even surface.
In some existing efforts, such as in ultrasound detection, solid Rexolite® or plastic wedges (or shoes) are used to couple the ultrasound into the pipe. When using plastic shoes, the shoes are machined so that the transducers are positioned at a correct angle to the pipe surface to create the wave mode as desired, while the contact area of the shoes is machined to fit the curvature of the pipe. While this approach works, it requires manufacturing a large number of shoes to cover the various diameters of pipes and other containers in use, since each pipe or other types of containers require a different radius shoe. This causes evident problems for service companies due to wedge delivery lead times and maintaining a large stock of custom wedges.
Furthermore, the user either needs transducers for each set of wedges, or has to move the transducers to a new set of wedges if a different pipe size is to be inspected. This is time consuming, and can result in damaged wedges and transducers due to the large amount of handling involved.
The present invention overcomes the problems of the prior art by providing a robust and conveniently adjustable probe holder that facilitates the coupling between probes and testing target surface, such that of pipes and other containers. The advantages that the present invention would become obvious with the disclosure as follows.
As noted, the present invention provides a convenient and robust probe holder with the height of the probe easily adjustable to fit for the coupling with test objects with non-flat surfaces, such as pipes and tubes, etc. The probe holder readily and easily situates the probe with adequate coupling and stable contact with various diameters of pipe or other test objects without the need to replace the wedge and probe. Coupling can be a variety of means, commonly known as wedges of solid plastic, rubber or water, etc. These wedges can be separate from the probe or integrated therein. This design eliminates the need for a new set of custom curved wedges for each pipe diameter. The compact size allows the probe to be used in confined areas encountered in inspections.
It should be noted that in the present disclosure, “wedge” and “delay-line” are used interchangeably. Furthermore, “sensor”, “transducer” and “probe” are used interchangeably.
Accordingly, it is a general object of the present disclosure to provide a probe holder, which can readily and easily situate probes with adequate and stable coupling with various diameters of test surfaces, such as those of pipes, tanks, plates, pressure vessels, etc., without the need to replace the wedge and/or probes.
It is further an object of the present disclosure to provide an acoustic probe/wedge holder that facilitates the operation of holding and sliding the probe over often non-flat test surfaces. The probe/wedge holder is configured to allow the adjustment of the probe/wedge so that the footing of the probe holder and the test surface of the wedge collectively match the surface of a test object, such as a pipe, allowing the wedge/probe and the probe holder to be stably and snugly disposed on or glide over the surface of the test object.
It is further an object of the present disclosure to employ a variety of delay line materials such as hard plastic (Rexolite®), rubber and water columns to be used with the herein disclosed probe/wedge holder.
It is further an object of the present disclosure to provide 0° adjustable wedges to be used with the herein disclosed probe/wedge holder.
It is further an object of the present disclosure to provide adjustable wedges for angle beam inspections to be used with the herein disclosed probe/wedge holder.
It is further an object of the present disclosure to provide an adjustable dual pitch-catch phased array probe to be used with the herein disclosed probe/wedge holder.
It should be further understood that the presently disclosed probe holder provides the advantages of simple-to-operate and improved coupling with a large range of test object surface curvatures due to the capability of adjusting the relative position of delay-lines and test surfaces.
Referring to
Also can be seen in
Readjusting probe holder for inspecting a different test object with a changed diameter is as easy as unlatching latch 8, situating probe holder 2 onto test surface and locking latch 8.
Turning now to
It is apparent that the size of probe 4 and probe holder 2 are so designed that probe 4 can be moved in and out of holder 2. There is, therefore, a small gap on both sides of the probe as well as at the latching position between the delay-line 4 and holder 2. The gaps herein described leave undesirable wiggling space between probe 4 and probe holder 2.
Continuing with
This novel design ensures the acoustic energy impinges perpendicularly onto test surface 15. In this embodiment, both angled surfaces 16 are advantageously designed at 45 degrees with respect to the long axis of the wedge (both the surfaces are separated by 90 degrees) which provides optimal tilt or skew restriction in all directions.
It should be noted that the above design is suitable for all embodiments herein disclosed.
Reference is now turned to
Referring now to
Referring now to
Water wedge 52 comprises its housing, irrigation barbs 66 and a water column (not shown) used for acoustic coupling. Water wedge 52 also includes a malleable gasket 58 which conforms to various diameters of said test object (not shown) and provides intimate contact between the test object and the water wedge 52.
It should be noted that water wedge 52 is built using known, conventional methods, being customized to fit into the novel probe holder. In other words, the presently disclosed probe holder 54 can be used to carry a wide range of water wedges, being slightly customized to fit into holder 54.
A slightly varied locking mechanism featuring a knob 62 and its matching bolt (not shown) is used in this alternative embodiment, replacing the latch in the preferred embodiment.
Similar to the preferred embodiment, water wedge 52 is vertically slidable within probe holder 54 via slot 64 and can be locked into a given vertical position via knob 62. Sharing further similarity with previously disclosed embodiments, water wedge 52 and probe holder 54 comprise matching opposing angled surfaces that are brought into intimate contact by tightening knob 62 to restrict tilting and screwing of wedge 52.
Probe holder 54 comprises axles 70 and wheels 60 which are brought into contact with the test object during an inspection. The adjustability of water wedge 52 and probe holder 54 in the vertical direction allows inspecting test objects with a large range of diameters, without changing the water wedge, while maintaining efficient coupling, stable contact and repeatable and appropriate alignment of the probe with the surfaces of test objects.
Referring to all embodiments, solid delay-line surfaces 14, 24, 34 and 35 are advantageously as small as possible in the passive phased array direction, while maintaining appropriate acoustic dimensions, in order to provide a contact area as small as possible, thereby providing appropriate coupling on the smallest possible surface curvature. The width of the delay-line surfaces depends principally but not exclusively on the delay-line material, the height of the delay-line and the size and frequency of the probe elements. The range of delay-line surface curvatures compatible with a given adjustable wedge depends on certain factors such as the size of delay-line surface 14 (or 24 or 34 and 35), the distance between wear footings (18 in preferred embodiment and 60 in the wheelable embodiment) and the length of slot 10.
The above descriptions and drawings disclose illustrative embodiments of the invention. Given the benefit of this disclosure, those skilled in the art should appreciate that various modifications, alternate constructions, and equivalents may also be employed to achieve the advantages of the invention.
For example, other configurations or other types of wedges such as water boxes, angle beam water wedges and rubber wedges can be used. In fact, any delay-line material may be used within the scope of the present invention.
It is very important to mention that the adjustability of the above mentioned wedges/probes is not limited to inspecting convex surfaces such as the exterior surface of pipes. The embodiments described herein can also be employed for inspecting concave surfaces such as the inside of pipes or tanks.
The locking mechanism embodied by the present invention is also not limited to the use of latches or knobs. For example, a single or a pair of spring loaded buttons can be devised so that pressing the buttons would allow the probe to move freely in vertical direction inside the probe holder to allow proper fitting of the coupling surface with the test object. Releasing the buttons would allow the spring(s) to exert pressure on the probe and to thereby firmly hold the probe during inspection sessions.
Nor is the invention limited to using opposing angled contact surfaces that provide two reference planes separated by 90 degrees. As such, almost any two opposing angled surfaces can be used and remain within the scope of the present invention. The invention is not limited to using the bar wear surfaces shown in the embodiments as disclosed. Other contact/confining methods such as three or four or any other number of contact points may be used.
For example, other confining and guiding mechanisms can include corresponding vertical tracks disposed on the probe's external surface and the probe holder's internal surface. The tracks can be configured to restrict probe's relative movement inside the probe holder in all directions, except allowing adjustment vertically.
It should be further noted that delay-lines described in the present disclosure can be of many forms or types of wedges, wear plates and integral wear plates, etc.
Further, the wheeling embodiment is not limited with respect to the type of wheels as shown. Any rolling mechanism, notably plastic and magnetic wheels can be used.
Although the embodiments described herein refer to repeatable and appropriate positioning of the passive direction of the phased array probe parallel to the surface of the test object such that the acoustic beam impinges perpendicularly onto the surface of the test object, the invention is not limited thereto. It is conceivable to employ the invention to a wedge for which the appropriate position of the probe with respect the surface of the test object comprises a skew angle in the passive phased array direction.
Although acoustic probe and wedge have been described in relation to particular exemplary embodiments, the probe holder according to the present disclosure can also be applied to other NDT/NDI probes. For example, eddy current probes, eddy current array probes, EMAT probes and bond testing probes. Advantageously, this invention can be employed to provide adjustable and constant lift-off for eddy current, eddy current array or EMAT probes.
Although the present invention has been described in relation to particular exemplary embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention not be limited by the specific disclosure.
