Abstract:
This disclosure describes an apparatus and a system for inspection of deepwater assets, e.g., pipes and pipelines that traverse the ocean floor. In one embodiment, the apparatus includes a housing that retains a compensation fluid therein to form a fluidic environment. A digital detector resides in the fluidic environment. The digital detector can generate digital images in response to radiation that penetrate though the deepwater asset and impinges on components of the digital detector. In one embodiment, the digital detector utilizes one or more seal members to secure the components together. The seal members may be permeable and/or impermeable to the compensation fluid thereby preventing and/or permitting migration of the compensation fluid between certain components of the digital detector.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to inspection and image acquisition and, more particularly, to embodiments of an apparatus and a system that can generate digital images of an asset located in environments at high pressures, e.g., pressures consistent with extreme depths below sea level. 
         [0002]    Inspection of assets including, for example, pipes and pipelines that reside underwater, is important to identify areas of the asset that may require pre-emptive maintenance or that represent a risk of failure. However, in many cases, these assets are found in environments that are not hospitable for humans to perform visual inspection. Nor could visual inspection, whether by human or remote visual inspection equipment, even ascertain defects, flaws, and other anomalies that are the source of failure in the asset because such anomalies may occur beneath the exterior surface of the asset. Thus, proper inspection may require use of special inspection equipment that can provide a view, or image, of the internal structure and health of the asset. 
         [0003]    Examples of this special inspection equipment include conventional x-ray and ultrasonic devices, both of which can penetrate the exterior surface of the asset to generate an image of the internal structure of the asset. However, neither of these types of devices are particularly well suited to inspect deepwater assets. To use ultrasonic devices for inspecting pipes underwater, for example, the ultrasonic device must be positioned proximate, and often in contact with, the surface of the asset. Unfortunately, these surfaces are often covered by protective coverings (e.g., insulation) or are generally not readily available without removal and/or manipulation of the protective covering from the area on which the ultrasonic device is to contact. 
         [0004]    X-ray devices, on the other hand, can penetrate through the protective coverings as well as any peripheral structure to capture images of the internal structure of the asset. However, most conventional x-ray devices require radiation to penetrate the asset and to expose imaging plates. These imaging plates must then traverse the ocean depths from the deepwater pipeline to the surface where the imaging plate can be viewed. This procedure is neither cost effective nor efficient, let alone practical when x-ray devices are used in connection with assets that are located many miles below the ocean surface. 
         [0005]    Another example of inspection equipment utilizes digital radiography to generate images of the asset. These digital radiography imaging systems generally use x-ray radiation to interact with digital flat panel x-ray detectors. In response to the radiation, the x-ray detectors generate digital signals that can traverse conduits from the asset to the ocean surface where digital processing equipment generates digital images. Such digital systems can provide higher image quality and improve processing time, image storage, and image transfer over previously known x-ray film techniques that expose conventional plates. However, digital radiography inspection systems may not be readily equipped for, nor can they operate at, the pressures that occur deep under the ocean surface where the deepwater assets are found. These pressures can, for example, damage equipment and/or induce anomalies in the digital images that degrade the overall image quality of digital radiography imaging systems. 
         [0006]    The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0007]    This disclosure describes embodiments of an apparatus, and a system incorporating the apparatus, with a housing that forms a fluid environment about a digital detector that is responsive to radiation. An advantage that the practice of some embodiments of the apparatus is to generate digital images at below the ocean surface and, in particular, find use at depths where deepwater pipes and pipelines are found. 
         [0008]    This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which: 
           [0010]      FIG. 1  depicts a perspective view of an exemplary apparatus that can generate digital images in response to radiation; 
           [0011]      FIG. 2  depicts a cross-section view of the exemplary apparatus of  FIG. 1 ; 
           [0012]      FIG. 3  depicts a perspective view of an exemplary detector for use in the apparatus of  FIGS. 1 and 2 ; 
           [0013]      FIG. 4  depicts a cross-section view of the exemplary detector of  FIG. 3 ; 
           [0014]      FIG. 5  depicts a perspective, exploded, assembly view of an exemplary detector for use in the exemplary apparatus of  FIGS. 1 and 2 ; 
           [0015]      FIG. 6  a cross-section, assembled view of the exemplary detector of  FIG. 5 ; and 
           [0016]      FIG. 7  depicts a block diagram of a digital imaging system that can incorporate the exemplary apparatus of  FIGS. 1 and 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]      FIG. 1  depicts a perspective view of an exemplary apparatus  100  that can cooperate with other equipment to generate digital images from radiation sources (e.g., isotope and Betatron radiation sources). The apparatus  100  is suitable for use at subsea depths and in other environments that exhibit relatively high pressures, e.g., depths of 3000 m or more. These digital images can show anomalies in an asset  102 , e.g., oil and gas pipes and pipelines. Such anomalies can often lead to structural failure of the asset  102 . The apparatus  100  includes a housing  104  that forms a sealed cavity  106 . In one construction, the housing  104  includes a front piece  108  and a back piece  110 , which couple to one another to hermetically seal and/or make the sealed cavity  106  water-tight. Although not shown, other elements, e.g., seals, gaskets, fasteners, and the like, may find use in construction of the housing  104  to secure its parts (e.g., the front piece  108  and the back piece  110 ) together. 
         [0018]    The apparatus  100  also includes a compensation fluid, generally identified by the numeral  112 . The compensation fluid  112  creates a fluidic environment inside of the sealed cavity  106  that is useful to compensate for pressure differentials the apparatus  100  may experience when in position proximate the asset  102 . In one embodiment, the apparatus  100  may also include a pressure compensation mechanism  114  that secures to the housing  104 . The pressure compensation mechanism  114  couples with the sealed cavity  106  to maintain the pressure of the compensation fluid  112  in the sealed cavity  110 . As also shown in  FIG. 1 , a detector element  116  resides in the sealed cavity  106  to position the detector element  116  in the fluidic environment and effectively immerse the detector element  116  in the compensation fluid  112 . The detector element  116  is responsive to radiation from the radiation source, generating in one example, a digital image that can be viewed at a location remote from the detector  116 . 
         [0019]    The pressure compensation mechanism  114  places the compensation fluid  112  under positive pressure to prevent fluids (e.g., seawater) from penetrating into the sealed cavity  110  in the event of mechanical failure in the housing  104 . This features can prevent damage to the detector  116  by allowing sufficient time to remove the apparatus  100  from its deepwater location. In one example, the pressure compensation mechanism  114  includes a bladder in fluid communication with the sealed cavity  106  and a spring or other mechanism that applies a force to the bladder. The bladder can hold a volume of the compensation fluid  112 , which flows between the bladder and the sealed cavity  110 , e.g., via a piece of tubing and/or conduit secured to the bladder and the housing  104 . During operation, pressure acts on the outside of the housing  104  and the bladder, thereby forcing compensation fluid  112  out of the bladder and into the sealed cavity  106 . The spring mechanism provides additional spring force, which positively pressurizes the sealed cavity  106 , thereby preventing water from entering the sealed cavity in the event of a leak or other failure in the structure of the housing  104  that exposes the sealed cavity  106  to the ambient environment. 
         [0020]    Examples of the compensation fluid  112  include oils (e.g., provided by Petro-Rite, Inc. under the Enviro-Rite brand) and, more particularly, include oils, lubricants, and like compositions of various weights and fluidic properties. These compositions may exhibit properties that are acceptable for use in aquatic environments where the asset  102  may be located. It is also desirable that the composition does not interfere with operation of the apparatus  100  to capture digital images of the asset  102 . Moreover, use of the composition fluid  112  can dissipate thermal energy. This feature of the compensation fluid  112  can maintain the detector  116  (and its components) at uniform temperature, which improves certain performance characteristics (e.g., image quality) of the detector  116 . 
         [0021]    The detector element  116  is responsive to radiation that penetrates through the asset  102 . In one example, the detector element  116  generates digital signals that, after further processing, render digital images in which anomalies in the asset  102  are visible. While details of the construction of the detector element  116  are found further below, generally the structure of the detector element  116  permits the detector element  116  to operate in the fluidic environment that is found in the sealed cavity  106 . Examples of the detector element  116  utilize various sealants that moderate penetration of the compensation fluid  112  into certain areas of the detector element  116 , while also preventing such penetration in other areas of the detector element  116 . Absence of such sealants may reduce clarity of the resulting digital images. Moreover, construction of the detector element  116  may also forgo use of foams and other porous and semi-porous materials. These materials can deform under pressure, resulting in air pockets that can show up as suspect anomalies in the digital images. 
         [0022]      FIG. 2  illustrates a cross-section view of the apparatus  100  taken along line A-A of  FIG. 1 . The view of  FIG. 2  shows the interior of the sealed cavity  106  and, more particularly, highlights certain details of the construction of the detector element  116 . In one embodiment, the detector element  116  has a layered structure  118  that includes a support panel  120 , which in one example comprises aluminum but can also comprise a variety of other materials (e.g., plastics, metals, composites, etc.). The support panel  120  couples with the housing  104  to suspend the detector element  116  within the sealed cavity  106 . For example, as shown in  FIG. 2 , the housing  104  can have one or more boss features  122  that support the support panel  120 . The boss features  122  can suspend the detector element  116  within the sealed cavity  106 , e.g., in spaced relation from one or more interior surfaces of the sealed cavity  106 . In one example, the boss features  122  are located in positions that space the detector element  116  from the front and back interior surfaces of the sealed cavity  106 . This disclosure does, however, envisage other configurations of components that can support the detector element  116  within the sealed cavity  106  as contemplated herein. 
         [0023]    Other components of the detector element  116  include a photodiode member  124  and an electronics component  126  secured to opposing sides of the support panel  120 . The photodiode member  124  includes a glass substrate  128  and a diode layer  130 . In one example, a film  132  (e.g., comprising a polyamide material often recognized as KAPTON®) resides between the glass substrate  128  and the support panel  120 . Other components of the detector element  116  include a scintillator member  134  that sits on top of the photodiode member  120 . The scintillator member  134  can have a scintillator screen member  136  and a protective member  138 . The scintillator screen member  136  can comprise comprising a luminescent material and/or material photosensitive to the radiation that impinges thereon. During operation, the scintillator screen member  136  absorbs photons from a radiation source and converts the photons into light photons. The light photons impinge on the photodiode member  124 , which converts the light photons to electrical signals. The electrical signals are read out by the electronics component  126 . In one example, the electronic component  126  turns the electrical signals into digital data that is sent to an image processor (not shown) for processing, e.g., into digital images. 
         [0024]    Additional details of embodiments of the apparatus  100  and, more particularly, examples of the detector element  116  are described next in connection with  FIGS. 3-6 .  FIGS. 3 and 4  focus on coupling of a photodiode member and a scintillator member to prevent fluid from migrating between these components and into the scintillator area.  FIG. 3 , for example, shows a portion of an exemplary detector element  200  that includes a photodiode member  224  with a glass substrate  228 . A scintillator member  234  resides on the glass substrate  228 . A first seal member  240  circumscribes the periphery of the scintillator member  234  to secure the scintillator member  234  to the glass substrate  228 . The first seal member  240  is, in one example, impermeable to fluid and, in particular, arranged as a barrier to prevent migration of the compensation fluid between the scintillator member  234  and the glass substrate  228  as discussed herein. 
         [0025]    As best shown in  FIG. 4 , the scintillator member  234  can include several components, e.g., a scintillator screen member  236  and a protective member  238 . The first seal member  240  can cover the peripheral edges of one or more of these components. This configuration of the first seal member  240  can prevent fluid migration between the scintillator member  234  and the glass substrate  228  and between the components of the scintillator member  234 . In one example, a portion of the first seal member  240  is disposed on the glass substrate  228  and a portion of the first seal member  240  is dispose on the scintillator member  234 . While these portions can vary in size, the present disclosure contemplates at least one configuration in which 50% of the material of the first seal member  240  may reside on the glass substrate  228  and 50% of the material of the first seal member  240  may reside on the scintillator member  234 . 
         [0026]      FIG. 5  depicts a portion of an exemplary detector element  300  with a support plate  320  and a photodiode member  324 . The detector element  300  also includes a second seal member  342  that traverses the surface of the support plate  320 . The second seal member  342  includes a plurality beads  344  and intervening gaps  346 , which collectively circumscribe a shape on the support plate  320  sufficient to secure the photodiode member  324  to the support plate  320 . As best shown in  FIG. 6 , in one example, the photodiode member  324  rests on top of the beads  344  to effectively secure the photodiode member  324  to the support plate  320 . 
         [0027]    Examples of materials for use as the first seal member  240  and the second seal member  342  include silicone compounds and other materials that the exhibit properties to permit operation of the first seal member  240  and the second seal member  342  as discussed herein. Selection of these material may take into account the composition of the compensation fluid, and vice versa, to avoid premature break-down that will dissipate sealing and adhesive capabilities of the first seal member  240  and the second seal member  342 . 
         [0028]      FIG. 7  depicts another exemplary apparatus  400  that can capture images of an asset  402  as part of a digital imaging system  448 . One or more of the elements that are discussed below may be omitted and/or modified to permit implementation of the digital imaging system  448  for inspecting deepwater assets. In one embodiment, the digital imaging system  448  includes a radiation source  450  (e.g., an isotope source and/or a Betatron source), a collimator  452  adjacent the radiation source  450 , and a positioner  454 . The positioner  454  can be a mechanical controller coupled to radiation source  448  and collimator  452  for controlling the positioning of radiation source  448  and collimator  452 . 
         [0029]    The digital imaging system  448  is designed to create images of the asset  402  by means of radiation and, as shown in the example of  FIG. 7 , a radiation beam  456  emitted by radiation source  450 , and passing through collimator  452 , which forms and confines the radiation beam  456  to a desired region, wherein the asset  402 , e.g., a deepwater pipeline is positioned. A portion of the radiation beam  456  passes through or around the asset  402 , and being altered by attenuation and/or absorption, continues on toward and impacts the apparatus  400 . As discussed above, the apparatus  400  converts photons received on its surface to lower energy light photons, and subsequently to electric signals, which are acquired and processed to reconstruct an image of internal structure within the asset  402 . 
         [0030]    The digital radiography imaging system  448  further includes a system controller  458  coupled to radiation source  450 , positioner  454 , and apparatus  400  for controlling operation of the radiation source  450 , positioner  454 , and apparatus  400 . The system controller  458  may supply both power and control signals for imaging examination sequences. In general, system controller  458  commands operation of the radiography system to execute examination protocols and to process acquired image data. The system controller  458  may also include signal processing circuitry, based on a general purpose or application-specific computer, associated memory circuitry for storing programs and routines executed by the computer, as well as configuration parameters and image data, interface circuits, and so forth. 
         [0031]    The system controller  458  may further include at least one processor designed to coordinate operation of the radiation source  450 , positioner  454 , and apparatus  400 , and to process acquired image data. The at least one processor may carry out various functionality in accordance with routines stored in the associated memory circuitry. The associated memory circuitry may also serve to store configuration parameters, operational logs, raw and/or processed image data, and so forth. In an exemplary embodiment, the system controller  458  includes at least one image processor to process acquired image data. 
         [0032]    The system controller  458  may further include interface circuitry that permits an operator or user to define imaging sequences, determine the operational status and health of system components, and so-forth. The interface circuitry may allow external devices to receive images and image data, and command operation of the radiography system, configure parameters of the system, and so forth. 
         [0033]    The system controller  458  may be coupled to a range of external devices via a communications interface. Such devices may include, for example, an operator workstation  460  for interacting with the digital imaging system  448 , processing or reprocessing images, viewing images, and so forth. In the case of tomosynthesis systems, for example, the operator workstation  460  may serve to create or reconstruct image slices of interest at various levels in the subject based upon the acquired image data. Other external devices may include a display  462  or a printer  464 . In general, these external devices  458 ,  462 ,  464  may be local to the image acquisition components, or may be remote from these components, e.g., on a ship or derrick, or in an entirely different location, linked to the image acquisition system via one or more configurable networks, such as the Internet, intranet, virtual private networks, and so forth. Such remote systems may be linked to the system controller  458  by any one or more network links. It should be further noted that the operator workstation  460  may be coupled to the display  462  and printer  464 , and may be coupled to a picture archiving and communications system (PACS). Such a PACS might be coupled to remote clients, such as a engineering department information systems, or to an internal or external network, so that others at different locations may gain access to image data. 
         [0034]    As used herein, an element or function recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the claimed invention should not be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
         [0035]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.