Polymer delay line for acoustic probe

Abstract

Various approaches can be used for performing acoustic scanning of a structure. A probe assembly can include a liquid delay line structure providing an acoustic delay to couple an acoustic transducer of the probe assembly to an object under test. According to the present teachings, a polymer structure and, optionally, a membrane can be used instead of a liquid delay line structure. A solid polymer slab can provide an acoustic delay line and can facilitate acoustic inspection of structures without requiring liquid couplant handling. For example, this allows inspection of structures in freezing conditions or inspection of surfaces that are hot enough that they would boil or otherwise degrade liquid couplant.

Description

POLYMER DELAY LINE FOR ACOUSTIC PROBECLAIM OF PRIORITY

[0001] This patent application claims the benefit of priority of Simon Alain, U.S. Provisional Patent Application Number 63 / 620,525, titled “POLYMER DELAY LINE FOR ACOUSTIC PROBE,” filed on January 12, 2024 (Attorney Docket No. 6409.281PRV), which is hereby incorporated by reference herein in its entirety.FIELD OF THE DISCLOSURE

[0002] This document pertains generally, but not by way of limitation, to apparatus and techniques for non-destructive inspection such as facilitating acoustic inspection, and more particularly, to apparatus and techniques for using a polymer slab and, optionally, a polymer membrane material, in addition to or instead of a liquid couplant at an interface between an active surface of an acoustic probe assembly and an object under inspection.BACKGROUND

[0003] Non-destructive testing (NDT) can refer to use of one or more different techniques to inspect regions on or within an object, such as to ascertain whether flaws or defects exist, or to otherwise characterize the object being inspected. Examples of non-destructive test approaches can include use of an eddy-current testing approach where electromagnetic energy is applied to the object and resulting induced currents on or within the object are detected, with the values of a detected current (or a related impedance) providing an indication of the structure of the object under inspection, such as to indicate a presence of a crack, void, porosity, or other inhomogeneity.

[0004] Another approach for NDT can include use of an acoustic inspection technique, such as where one or more electroacoustic transducers are used to insonify a region on or within the object under inspection, and acoustic energy that is scattered or reflected can be detected and processed. Such scattered or reflected energy can be referred to as an acoustic echo signal. Generally, such an acoustic inspection scheme involves use of acoustic frequencies in an ultrasonic range of frequencies, such as including pulses having energy in a specified range that can include values from, forexample, a few hundred kilohertz, to tens of megahertz, as an illustrative example.SUMMARY OF THE DISCLOSURE

[0005] Acoustic inspection is a non-destructive test (NDT) approach that can be used to evaluate structures such as pipes, vessels, plates, or welds related thereto, as illustrative examples. Such evaluation can include thickness gauging, corrosion monitoring, or inspection for defects such as voids or porosities in structures. In order to couple acoustic energy between an active surface of an acoustic transducer (or an array of such transducers) and an object under inspection, a coupling medium is generally used. For example, in one approach, a “delay line” can be formed by a column of water located between an active surface of the acoustic transducer and the object under inspection.

[0006] The present inventors have recognized, among other things, that use of a liquid delay line can present various challenges. For example, a temperature range of operation of the acoustic inspection system can be limited, such as precluding measurements being made in freezing conditions or when a surface being inspected is above a boiling point or thermal decomposition temperature for a liquid couplant. Other challenges can exist in relation to use of fluid couplant, such as maintaining couplant flow as the probe assembly is moved over a large scanning area. For example, if no couplant recovery is performed, a significant volume of couplant can be consumed during testing, or, to preclude such waste, the object under inspection may be submerged, which is either cumbersome, or not practical for larger structure such as pipelines or pressure vessels.

[0007] The present inventors have recognized that a solid polymer delay slab can be used, such as instead of a liquid couplant to form a delay line. The present inventors have also recognized that use of generally-available polymer materials having suitable acoustic properties may not provide mechanical robustness, being vulnerable to rapid wear or tearing. Accordingly, the present inventors have also recognized that a protective membrane can be used in combination with a solid polymer delay slab, such as to protect a surface of the polymer delay slab that is in proximity to the object under inspection. Such a polymer delay line and membrane can form a portion of an inspection probe assembly.

[0008] In an example, a non-destructive test apparatus can include an acoustic probeassembly, the acoustic probe assembly comprising a housing, an acoustic transducer mounted on or within the housing, the acoustic transducer defining an active surface from which acoustic energy is transmitted or to which received acoustic energy is coupled, or both, a polymer slab defining a first surface that is acoustically coupled with the active surface of the acoustic transducer, and an opposite second surface that is oriented outward from the acoustic probe assembly, and, optionally, a membrane configured to protect the opposite second surface of the polymer slab. For example, the acoustic probe assembly can include a retaining plate configured to retain the polymer slab and the membrane. In an example, a scanner assembly comprising a carriage can mechanically house the acoustic probe assembly. The scanner assembly can include an operator interface comprising a user input and a display, the operator interface separate from a non-destructive test instrument that is communicatively coupled with the scanner assembly. In an example, a method for performing non-destructive test can include mating an acoustic probe assembly with a carriage of a scanner assembly, establishing communication between a nondestructive test instrument and the scanner assembly, and performing an acoustic inspection without requiring continuously supplying a couplant to an interface between the acoustic probe assembly and an object under inspection.

[0009] This summary is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0011] FIG. 1 illustrates generally an example comprising an acoustic inspection system, such as can include or use the polymer delay line and membrane structure shown and described in this document.

[0012] FIG. 2A, FIG. 2B, and FIG. 2C illustrate generally respective views of ascanner assembly that can house an acoustic transducer probe assembly, such as can include or use the polymer delay line and membrane structure shown and described in this document.

[0013] FIG. 3 illustrates an exploded view of an illustrative example comprising an acoustic transducer probe assembly, comprising a polymer delay line and membrane.

[0014] FIG. 4 illustrates generally a gasket and gasket protector arrangement, such as can be used with or included as a portion of the acoustic transducer probe assembly of FIG. 3.

[0015] FIG. 5 illustrates generally a scanner assembly located on an object under inspection, and a non-destructive test instrument, such as communicatively coupled with the scanner assembly.

[0016] FIG. 6 illustrates generally a technique, such as for performing an acoustic inspection, such as can use the acoustic transducer probe assembly as shown and described in relation to FIG. 2A, FIG. 2B, FIG. 2C, FIG. 3, FIG. 4, or combinations thereof.DETAILED DESCRIPTION

[0017] Various approaches can be used for performing acoustic scanning of a structure. A probe assembly can include a liquid delay line structure providing an acoustic delay to couple an acoustic transducer of the probe assembly to an object under test. According to the present teachings, a polymer structure and, optionally, a membrane can be used instead of a liquid delay line structure. A solid polymer slab can provide an acoustic delay line and can facilitate acoustic inspection of structures without requiring liquid couplant handling. For example, this allows inspection of structures in freezing conditions or inspection of surfaces that are hot enough that they would boil or otherwise degrade liquid couplant.

[0018] The present subject matter can include or use a solid polymer slab, such as located between an active surface of an acoustic (e.g., ultrasound) transducer and an object under inspection. The polymer slab can couple acoustic energy between the transducer and the object under inspection, such as serving as a delay line that isolates the transducer from a surface of the object under test. Use of a polymer slab as a delay line can reduce or eliminate liquid couplant use. For example, as shown and described herein, a membrane structure can be included, such as between a surface of a solidpolymer slab and an object under inspection. The membrane can protect the polymer slab from abrasion or tearing. A minimal amount of coupling fluid such as water or gel can but need not be used at an interface between the membrane and the object under test. Accordingly, acoustic inspection can be performed without requiring continuously supplying a couplant to an interface between the acoustic transducer probe assembly and an object under inspection.By contrast, in an approach where a liquid (e.g., water) delay line configuration is used, a constant feed of water is usually provided, along with provisions for suppressing or avoiding bubble formation. Such a liquid acoustic coupling approach can also be impractical for use in conditions where the liquid would either freeze or boil, or where water circulation equipment such as pumps and hoses would be cumbersome or even impractical.

[0019] FIG. 1 illustrates generally an example comprising an acoustic inspection system 100, such as can include or use the polymer delay line 161 and, optionally, a membrane structure 159 as shown and described in this document. The inspection system 100 can include a test instrument 140, such as a hand-held or portable assembly. The test instrument 140 can be electrically coupled to a probe assembly 150, such as using a multi -conductor interconnect 130. The probe assembly 150 can include one or more electroacoustic transducers, such as a transducer array 152 including respective transducers 154A through 154N. The elements need not be square in footprint or arranged along a straight-line axis. Element size and pitch can be varied according to the inspection application.

[0020] A modular probe assembly 150 configuration can be used, such as to allow a test instrument 140 to be used with various different probe assemblies. In an example, the transducer array 152 includes piezoelectric transducers, such as can be acoustically coupled to a target 158 (e.g., a test specimen or “object-under-test”) through a solid polymer slab comprising a delay line 161. As discussed in more detail below, the delay line can be used in place of a liquid (e.g., water) delay line. A membrane structure 159 can help protect the delay line 161, such as to suppress abrasion, snagging, or tearing. A coupling medium 156 can still be used, such as between the membrane structure 159 and the target 158. The coupling medium can include a fluid or gel. For example, water can be sprayed or injected between the probe assembly 150 and the structure under test. Use of a polymer delay line 161, and,optionally, a membrane structure 159, can reduce or eliminate a need for a fluid or gel couplant as a coupling medium 156 at the interface between the target 158 and the probe assembly 150.

[0021] The test instrument 140 can include digital and analog circuitry, such as a front-end circuit 122 including one or more transmit signal chains, receive signal chains, or switching circuitry (e.g., transmit / receive switching circuitry). The transmit signal chain can include amplifier and filter circuitry, such as to provide transmit pulses for delivery through an interconnect 130 to a probe assembly 150 for insonification of the target 158, such as to image or otherwise detect a flaw 160 on or within the target 158 structure by receiving scattered or reflected acoustic energy elicited in response to the insonification.

[0022] While FIG. 1 shows a single probe assembly 150 and a single transducer array 152, other configurations can be used, such as multiple probe assemblies connected to a single test instrument 140, or multiple transducer arrays 152 used with a single probe assembly 150 or multiple probe assemblies for pitch / catch inspection modes. Similarly, a test protocol can be performed using coordination between multiple test instruments 140, such as in response to an overall test scheme established from a master test instrument 140 or established by another remote system such as a compute facility 108 or general-purpose computing device such as a laptop 132, tablet, smartphone, desktop computer, or the like. The test scheme may be established according to a published standard or regulatory requirement and may be performed upon initial fabrication or on a recurring basis for ongoing surveillance, as illustrative examples.

[0023] The receive signal chain of the front-end circuit 122 can include one or more filters or amplifier circuits, along with an analog-to-digital conversion facility, such as to digitize echo signals received using the probe assembly 150. Digitization can be performed coherently, such as to provide multiple channels of digitized data aligned or referenced to each other in time or phase. The front-end circuit can be coupled to and controlled by one or more processor circuits, such as a processor circuit 102 included as a portion of the test instrument 140. The processor circuit can be coupled to a memory circuit 104, such as to execute instructions that cause the test instrument 140 to perform one or more of acoustic transmission, acoustic acquisition, processing, or storage of data relating to an acoustic inspection, or to otherwise perform techniques as shown and described herein. The test instrument 140 can becommunicatively coupled to other portions of the system 100, such as using a wired or wireless communication interface 120.

[0024] For example, performance of one or more acoustic inspection techniques can be accomplished on-board the test instrument 140 or using other processing or storage facilities such as using a compute facility 108 or a general -purpose computing device such as a laptop 132, tablet, smart-phone, desktop computer, or the like. For example, processing tasks that would be undesirably slow if performed on-board the test instrument 140 or beyond the capabilities of the test instrument 140 can be performed remotely (e.g., on a separate system), such as in response to a request from the test instrument 140. Similarly, storage of imaging data or intermediate data such as A- scan matrices of time-series data or other representations of such data, for example, can be accomplished using remote facilities communicatively coupled to the test instrument 140. The test instrument can include a display 110, such as for presentation of configuration information or results, and an input device 112 such as including one or more of a keyboard, trackball, function keys or soft keys, mouseinterface, touch-screen, stylus, or the like, for receiving operator commands, configuration information, or responses to queries.

[0025] To illustrate the use of a polymer slab as a delay line structure, various examples are discussed below, using a circumferential scanner as an illustrative - but non-limiting - example of an application for a polymer delay line. In applications involving circumferential scanning of round or tubular structures such as pipes or vessels, a scanning approach can include use of a phased-array ultrasound transducer assembly. One approach can include manually placing a test probe assembly in an axial location along the object under inspection, and then manually rolling or sliding the test probe assembly in a circumferential direction to perform a scan (e.g., to acquire respective A-scans or compile a C-scan view, as illustrative examples). After a circumferential “line” scan is completed, the test probe assembly can be moved to a new axial location (e.g., “indexed”) and another scan can be performed. In such an approach, which can be referred to as raster scanning, a composite can be assembled of respective circumferential scans.

[0026] FIG. 2A, FIG. 2B, and FIG. 2C illustrate generally respective views of a scanner assembly 250 that can house an acoustic transducer probe assembly 253, such as can include or use the polymer delay line and membrane structure shown anddescribed in this document. As shown in FIG. 2A, FIG. 2B, and FIG. 2C, the scanner assembly 250 can be modular, such as allowing use of different acoustic transducer probe assembly 253 configurations (e.g., such as support an acoustic transducer 252 comprising an array having a specified count of acoustic transducer elements such as defining a specified aperture width or having other specified characteristics). The transducer 252 can be communicatively coupled with an analog front end on a separate acoustic inspection instrument, such as through a cable 230. The acoustic probe assembly can include a retaining plate 256 and housing 283 such as to provide a couplant chamber (e.g., housing a polymer slab as a delay line) and to support a membrane. For example, a foam or other gasket can be located on a surface 255 of the retaining plate 256, such as to wet or retain a small amount of liquid couplant in a region of an object under inspection near an exposed surface 265 of a membrane structure.

[0027] The scanner assembly 250 can include a carriage 270 such as defining or otherwise including a region 249 to receive the acoustic transducer probe assembly 253 to mechanically house the acoustic transducer probe assembly 253. The carriage 270 can include wheels 272 aligned to rotate in a first direction (e.g., defining a scan axis for acquiring a line scan circumferentially around a cylindrical or tubular object under inspection). The wheels 272 can be magnetized or can contain a permanent magnet so that the carriage 270 is held against a ferromagnetic object under inspection during scanning. As shown in FIG. 2A, FIG. 2B, and FIG. 2C, an operator interface 262 can be removably mated with the carriage 270. For example, the operator interface 262 can include one or more user inputs and a display. The operator interface 262 can house or otherwise include one or more encoders, such as a first encoder 267 that can monitor rotation of one or more of the wheels 272, forming a scan encoder assembly 264. The operator interface can include an electrical connector 263 or other provision for communication and power, such as for interconnection via a cable and connector 263 with a separate acoustic inspection instrument. One or more of a couplant line (if present), the cable 230, or a cable coupled with the connector 263 can be bundled together can held within a cable loom or umbilical bundle 274.

[0028] The scanner assembly 250 can include a second wheel 268, such as configured to rotate in a second direction orthogonal to a direction of rotation of the wheels 272.Such a direction can be an axial (e.g., “index” direction) along the object under inspection. For example, as shown in the illustration of FIG. 2A, an index encoder assembly 266 can house a second encoder that can monitor rotation of the second wheel 268. The first wheels 272 and the second wheel 268 can be configured to rotate exclusively in their respective directions (e.g., the first wheels 272 rotate for movement along the first direction and the second wheel 268 rotates for movement along the orthogonal second direction).

[0029] The operator interface 262 can provide an indication to a user, such as a status indication indicative of whether a first encoder, a second encoder, or both are active, or otherwise indicating an active operational mode of the scanner assembly 250. As shown in FIG. 2B and FIG. 2C, the index encoder assembly 266 can include a stow lever 251, such as to raise or lower the second wheel 268. The second wheel 268 can also include other features such as to limit binding or facilitate sliding the circumferential direction. For example, as shown in FIG. 2A, FIG. 2B., and FIG. 2C, the second wheel 268 can be beveled.

[0030] FIG. 3 illustrates an exploded view of an illustrative example comprising an acoustic transducer probe assembly 253 of a non-destructive test apparatus, where the acoustic transducer probe assembly 253 comprises a polymer delay line 261 (e.g., a solid polymer slab) and, optionally, a membrane structure 259. The retaining plate 256 can house or support a gasket (such as shown in FIG. 4), or can be made of either porous (e.g., moisture absorbing) or non-porous material, and can include or define a beveled edge 282 to suppress one or more of binding of, pinching of, or damage to the retaining plate 256 or an exposed surface 265 of the membrane structure 259 that can protrude through an aperture 269 include in or defined by the retaining plate 256. In the example shown in FIG. 3, the membrane structure 259 extends inwards and conforms to a profile of the polymer delay line 261. The present inventors have also recognized that when the acoustic transducer probe assembly 253 is assembled, any gaps at internal interfaces between various elements in the acoustic propagation path can cause unwanted loss or reflections.

[0031] To help suppress such gaps, the retaining plate 256 can keep the membrane structure 259 captive, such as by engaging a tab defined by the membrane structure extending laterally outward from the membrane structure 259, such as completely encircling the membrane structure. For example, when the retaining plate 256 isscrewed together with a housing 283, the polymer delay line 261 can be slightly compressed, with a first surface 275 compressed against an active surface 273 of an acoustic transducer 252 (or array of such transducers), and an opposite second surface 277 oriented outward and compressed against the membrane structure 259. The tab extending laterally outward can rest on a corresponding shoulder 271 of the housing, with the exposed surface 265 of the membrane structure 259 protruding through the aperture 269. This arrangement can help to make the assembly, including the region around the membrane structure 259, liquid tight. In another example, the membrane structure 259 can cover or otherwise occupy the aperture 269, such as applied to an outer surface 255 of the retaining plate 256.

[0032] An acoustic coupling medium such as a gel or liquid can be applied to internal interfaces between components of the acoustic probe assembly 253 such as during assembly or maintenance, such as at the first surface 275 and the second surface 277 of the polymer delay line 261. Such internal interfaces can be isolated from an environment surrounding the acoustic probe assembly. Compression of the polymer delay line 261, the membrane structure 259, and the active surface 273 together can reduce or eliminate any need for a gel or liquid at the interfaces between the components of the acoustic probe assembly 253, such as providing an acoustic transducer probe assembly 253 that is more suitable for use in extreme temperatures or harsh environments. The acoustic transducer probe assembly 253 can include other portions, such as a plate 281 or gasket between the acoustic transducer 252 and the housing 283 such that the acoustic transducer is mounted to the housing 283 and extends through at least a portion of the housing 283.

[0033] As mentioned above, in one approach, a liquid delay line can be used. One aspect of a liquid delay line is that it is conformable making it easy to couple with a potentially irregular or curved surface of an object under inspection, and generally, liquid delay lines couple acoustic energy efficiently between an acoustic transducer and the object under inspection (e.g., with acceptable attenuation and dispersion). The polymer delay line 261 and the membrane structure 259 shown in the example of FIG. 3 can be compliant, providing conformability of the polymer delay line 261 and membrane structure 259 to a curved or irregular surface. However, use of a solid polymer such as the polymer delay line 261 shown in FIG. 3 can present various challenges. Some polymer materials may not have desirable acoustic characteristics,such as exhibiting a mismatch in acoustic propagation velocity in the desired mode, unacceptable attenuation, or undesirable physical properties such as being too hard, sticky, or being vulnerable to mechanical damage such as abrasion or tearing. The present inventors have recognized that use of a membrane structure 259 can help to address such challenges, such as allowing use of polymer materials having desirable acoustic properties, while the membrane provides a mechanically robust surface that is less susceptible to wear, snagging, or tearing, than an exposed face of a polymer delay line 261. Use of the configuration shown in FIG. 3 can also facilitate replacement of the membrane structure 259, such as a wearable item, without requiring removal or replacement of the polymer delay line 261.

[0034] Various materials can be used for the polymer delay line 261. For example, one or more of a thermoplastic material such as a thermoplastic polymer from the Aqualink™ series (Innovation Polymers, Ontario, Canada) can be used, or a polymer otherwise having, as an illustrative example, an acoustic propagation velocity between about 1400 meters per second and about 1500 meters per second, or a Shore A hardness between about 1 and about 5, or combinations of such acoustic propagation velocity and hardness. For applications involving higher temperatures, a silicone- based material can be used, such as from the AquaSilox series (Innovation Polymers, Ontario, Canada), such as having heat resistance up to about 300 degrees Celsius. Examples of silicone-based material can include an acoustic propagation velocity of about 100 meters per second, or a Shore A hardness between about 20 and about 45, or combinations of such acoustic propagation velocity and hardness. Membrane structure 259 materials can include one or more of a poly imide material, such as a Kapton® film (DuPont de Nemours, Inc.), a poly etheretherketone (PEEK) material, or a poly etherimide (PEI) material such as formed using an Ultem™ resin. Such examples are merely illustrative and other materials can be used.

[0035] In some applications, a wetted foam or sponge-like gasket material may be used to apply or retain a small amount of a liquid or gel couplant at or near an exterior surface of the membrane structure 259 such as at the exposed surface 265. For example, FIG. 4 illustrates generally a gasket 279 and gasket protector 278 arrangement, such as can be used with or included as a portion of the acoustic transducer probe assembly of FIG. 3, such as clipped to or otherwise supported by the retaining plate 256 of FIG. 3. Referring to FIG. 4, the gasket protector 278 and gasket279 can each define apertures 269B and 269C respectively, that correspond to the aperture 269 of the retaining plate 256 of FIG. 3, through which the exposed surface 265 of the membrane structure 259 protrudes (or through which the second surface 277 of the polymer delay line 261 protrudes if no membrane structure 259 is used). Use of a gasket protector 278 can help to avoid wear or damage to a compliant foam or sponge-like gasket 279 and can facilitate easy replacement or inspection of such a gasket 279.

[0036] FIG. 5 illustrates generally an acoustic inspection system 700 comprising a scanner assembly 750 located on an object under inspection 758, and anon- destructive test instrument 740, such as communicatively coupled with the scanner assembly (e.g., a separate acquisition instrument that stores the inspection data acquired by the scanner assembly 750), such as communicatively coupled with the scanner assembly 750. The scanner assembly 750 can include an acoustic inspection probe assembly as shown and described in other examples herein, such as shown and described in relation to FIG. 2A, FIG. 2B, FIG. 2C, FIG. 3, FIG. 4, or combinations thereof. While FIG. 5 shows the indexing direction as an axial direction, and the scan direction as a circumferential direction, with a cylindrical object under test, the apparatus and techniques described in this document are applicable to other objects and orientations. For example, a scan direction can be longitudinal or axial, instead of circumferential. Planar objects can also be inspected using the approaches and apparatus described herein.

[0037] FIG. 6 illustrates generally a technique 600, such as a method for performing an acoustic inspection, such as can use the acoustic transducer probe assembly as shown and described in relation to FIG. 2A, FIG. 2B, FIG. 2C, FIG. 3, FIG. 4, or combinations thereof. The technique 600 can include, at 605, mating an acoustic transducer probe assembly with a carriage of a scanner assembly. For example, as shown and described above, a scanner can be modular, such as supporting different acoustic transducer probe types or geometries for different applications. At 610, communication can be established between a non-destructive test instrument and the scanner assembly, such as through a conductive cable interconnection or through wireless communication, or combinations thereof. At 615, an acoustic inspection can be performed, such as corresponding to one or more acoustic acquisitions, such as without requiring continuously supply a couplant to an interface between the acousticprobe assembly and an object under inspection, where the acoustic probe assembly using a solid polymer slab for acoustic coupling instead of a liquid delay line.Various Notes

[0038] Each of the non-limiting aspects above can stand on its own or can be combined in various permutations or combinations with one or more of the other aspects or other subject matter described in this document.

[0039] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to generally as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0040] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls.

[0041] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0042] The above description is intended to be illustrative, and not restrictive. Forexample, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may he in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

THE CLAIMED INVENTION IS:

1. A non-destructive test apparatus comprising: an acoustic probe assembly, the acoustic probe assembly comprising: a housing; an acoustic transducer mounted on or within the housing, the acoustic transducer defining an active surface from which acoustic energy is transmitted or to which received acoustic energy is coupled, or both; a polymer slab defining a first surface that is acoustically coupled with the active surface of the acoustic transducer, and an opposite second surface that is oriented outward from the acoustic probe assembly; and a membrane configured to protect the opposite second surface of the polymer slab.

2. The non-destructive test apparatus of claim 1, wherein the acoustic probe assembly comprises a retaining plate configured to retain the polymer slab and the membrane.

3. The non-destructive test apparatus of claim 2, wherein the retaining plate supports or contains a gasket.

4. The non-destructive test apparatus of any of claims 2 or 3, wherein at least one portion of the retaining plate is beveled.

5. The non-destructive test apparatus of any of claims 2 through 4, wherein the retaining plate defines an aperture occupied by, or covered by, the membrane.

6. The non-destructive test apparatus of any of claims 1 through 5, wherein the membrane comprises one or more tabs extending laterally outward from the membrane for use in retaining the membrane.

7. The non-destructive test apparatus of any of claims 5 or 6, wherein the membrane is exposed in the aperture and covered by the retaining plate elsewhere.

8. The non-destructive test apparatus of any of claims 1 through 7, wherein at least a portion of the membrane extends inwards to conform to a profde of the polymer slab at or near the second surface of the polymer slab.

9. The non-destructive test apparatus of any of claims 1 through 8, wherein an interface between an active surface of the acoustic transducer and the polymer slab comprises a liquid or gel couplant.

10. The non-destructive test apparatus of any of claims 1 through 9, wherein an interface between the second surface of the polymer slab and the membrane comprises a liquid or gel couplant.

11. The non-destructive test apparatus of any of claims 9 or 10, wherein one or more internal interfaces comprising a liquid or gel couplant are isolated from an environment surrounding the acoustic probe assembly.

12. The non-destructive test apparatus of any of claims 1 through 11, wherein the membrane comprises a polyimide material.

13. The non-destructive test apparatus of any of claims 1 through 11, wherein the membrane comprises a poly etheretherketone (PEEK) material.

14. The non-destructive test apparatus of any of claims 1 through 11, wherein the membrane comprises a poly etherimide (PEI) material.

15. The non-destructive test apparatus of any of claims 1 through 14, wherein the polymer slab comprises a thermoplastic material.

16. The non-destructive test apparatus of claim 15, wherein the thermoplastic material comprises an acoustic propagation velocity between about 1400 meters per second and about 1500 meters per second, and a Shore A hardness between about 1 and about 5.

17. The non-destructive test apparatus of any of claims 1 through 14, wherein the polymer slab comprises a silicone-based material.

18. The non-destructive test apparatus of claim 17, wherein the silicone-based material comprises an acoustic propagation velocity of about 100 meters per second, and a Shore A hardness between about 20 and about 45.

19. A scanner assembly, comprising a carriage configured to mechanically house an acoustic probe assembly of the non-destructive test apparatus of any of claims 1 through 18; and an operator interface comprising a user input and a display, the operator interface separate from a non-destructive test instrument that is communicatively coupled with the scanner assembly.

20. A method for performing non-destructive test, comprising: mating an acoustic probe assembly of any of claims 1 through 18 with a carriage of a scanner assembly; establishing communication between a non-destructive test instrument and the scanner assembly; performing an acoustic inspection without requiring continuously supplying a couplant to an interface between the acoustic probe assembly and an object under inspection.