Patent Application
20140067185
The subject matter disclosed herein relates to turbines. More particularly, aspects of the disclosure relate to systems for in-situ inspection of components in a turbine using robotic infrared (IR) thermography and/or other miniaturized inspection methods.
During operation of a turbomachine (e.g., a gas turbine), components within that turbine (e.g., rotor and stator blades) are exposed to high pressures and temperatures, which can cause the protective thermal coatings to degrade and spall and cracks to form in the components. Early detection of crack formation and coating health are desirable so that suitable measures can be initiated to fix or replace components, before serious consequences occur.
Visual inspections of components can be done, but visual inspection is unreliable, and cannot detect cracks that have no surface opening (i.e., closed cracks) or delaminations of the coatings. Even when a visible crack with a surface opening (i.e., an open crack) is detected, it is not possible to quantify depth of the crack using visual inspection. In addition, unless there is an obvious spallation of the coatings their health is difficult to judge. Conventionally, a complimentary modality, such as ultrasonic testing (UT) or eddy current (EC) or x-ray or gamma-ray radiographic imaging needs to be used to obtain this quantification (e.g., length, depth, etc.) and also to detect closed cracks that could be missed using a visual only approach. UT and EC modalities require a coupling medium or equi-pressure surface contact, respectively, which is not necessary for visual/optical, IR or radiographic inspections.
Systems for inspecting components in-situ within an assembled turbomachine are disclosed. At least one miniature robotic device is used to travel around a surface of a component to be inspected. The robotic device includes a non-destructive testing structure mounted thereon, configured to gather data related to the surface under the miniature robotic device. In one embodiment, the non-destructive testing structure uses infrared (IR) thermography, e.g., an IR heat source, to direct heat towards the surface to be inspected, and an image capture device to take thermal images of the surface. Data from the non-destructive testing structure can then be analyzed by a computing device to identify and quantify cracks and/or defects in the component being inspected.
A first aspect of the invention includes a system for inspecting a component in-situ within an assembled turbomachine, the system comprising: at least one miniature robotic device configured to travel around a surface of the component, the at least one robotic device having a non-destructive testing structure attached thereto configured to gather data related to the surface; and at least one computing device connected to the at least one miniature robotic device, the at least one computing device configured to receive data from the at least one miniature robotic device relating to the surface of the component.
A second aspect of the invention includes a method of inspecting components in-situ within an assembled turbomachine, the method comprising: providing a plurality of miniature robotic devices, each robotic device having a non-destructive testing structure attached thereto; simultaneously moving the plurality of miniature robotic devices around a surface of a component; and receiving data from at least one non-destructive testing structure.
These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which:
It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.
Systems for inspecting surfaces of components in-situ within a turbomachine, e.g., blades or vanes, are disclosed. As discussed in more detail herein, in one embodiment, structured infrared (IR) light is created, e.g., multiple lines using programmable light emitting diodes (LEDs), and a cooled IR focal plane detector chip can then image surface temperature as a function of time. Multiple robots with LED driven sources and IR detectors can be spread out over the surface area of interest, enabling full coverage. The thermal images can be converted into time-of-flight maps and temperature maps at a specific critical time, synchronized with IR LEDs on-off triggers. These images can give a direct indication of a defect size. Comparison can then be carried out with optical images. The resulting fused images directly supply quantitative defect information.
Turning to
As shown in
Each miniature robotic device 104 includes a non-destructive testing structure attached thereto. In one embodiment, the non-destructive testing structure can use infrared (IR) thermography to gather data related to the surface of blade 102 under device 104. However, as discussed herein, other non-destructive testing structures can be used, for example, optical imaging, ultrasonic testing (UT), x-ray or gamma-ray radiography or eddy current (EC).
In one embodiment, as shown in more detail in
Image capture device 106 is configured to take thermal images of the surface of blade 102, for example, of the surface under, or proximate to, robotic device 104. A plurality of thermal images can be taken, each showing a temperature of blade 102. As shown in
It is also possible that through-component heat flow can be measured by positioning IR heat source 108 and image capture device 106 on two different robots on the opposite surfaces of 102, as shown in
As shown in
In another embodiment, shown in
Each non-destructive testing structure on each robotic device 104 is connected to at least one computing device 110. The connection to computing device 110 can be wired or wireless, as known in the art. In one embodiment, robotic device 104 includes an antenna configured to receive and send signals to/from computing device 110. Such signals can comprise instructions to the robotic device instructing it how to move across the surface, and/or instructions to image capture device 106 or IR heat source 108. In addition to receiving signals, robotic device 104 and/or the components attached thereto, can send signals to computing device 110. For example, sending data related to the surface being inspected, e.g., images from image capture device 106.
A method using system 100 to inspect a component in a turbomachine is shown in
Computing device 110 can analyze the thermal images, for example, converting the images into time-of-flight maps and temperature maps at specific times, synchronized with the IR LEDs on-off triggers. These thermal images can give a direct indication of defect size. Computing device 110 can then compare the thermal images with optical images (e.g., taken with another image capture device similar to image capture device 106, but sensitive to visible light as opposed to IR; or previously obtained). The resulting fused images directly supply quantitative defect information.
Embodiments of the invention allow IR thermography to be used in small or hard to access spaces. The robotic devices allow testing structures to reach areas of a turbomachine that are typically only reachable when the turbomachine is disassembled. For example, multiple robots can be programmed to enter a structure of interest, and inspections can be performed in-situ, without disassembling the structure, e.g., a gas turbine. While embodiments of this invention have been discussed in connection with blades in a turbomachine, it is understood that any conventionally hard to reach surface can be inspected using embodiments of this invention, for example, vanes, blades, buckets, and/or nozzles in a turbomachine.
Embodiments of this invention use IR thermography to detect and quantify defects in a surface to be inspected. IR heat source 108 produces heat in various patterns shown in
In either case, the LED heat source of this invention moves over the full surface to be inspected, e.g., by using an array of co-robots 104 that allow synchronized measurements over the whole surface. Whereas the conventional IR thermography requires large space and high intensity lamps, the embodiments of this invention allow IR thermography to be used in closed spaces (e.g. inside gas turbine—in small spaces between blades and airfoils) and since local heating is delivered, small LED sources are sufficient. Embodiments of this invention are LED based, near field method, thus allowing smaller power and exact electronic control of LED on-off and emitted pattern control.
In another embodiment of the invention, the array of miniature robotic devices 102 can also be used to monitor or inspect for additional things, other than cracks. For example, parts in a turbomachine can include a protective coating, which, over time, can lift or peel. The array of miniature robotic devices 102 can be used to determine the state of that protective coating, i.e., determining whether it is cracking, peeling, lifting, etc.
Any modality can be used with this array of miniature robotic devices 104, for example, IR thermography, optical imaging, EC, or UT, or X-ray or Gamma-ray radiography. As discussed herein, in other embodiments, other non-destructive testing structures can be used in conjunction with miniature robotic devices 104. For example, an optical image can be obtained using image capture device 106 connected to robotic device 104. Such optical images taken of the surface directly below, or proximate to, device 104 would be desirable as image capture device 106 would be substantially perpendicular to the surface, in other words, a direct view of the surface could be obtained. In contrast, when conventional image capture devices, such as borescopes, are used, a skewed perspective angle results in incomplete coverage or angled views of the surface. In other embodiments, the non-destructive testing device comprises devices such as small ultrasonic transducers for ultrasonic testing (UT) or flexible, micropatterned eddy current arrays called ECAPs (Eddy Current Array Probes). In addition, very small size x-ray and gamma-ray sources such as Irridium-192, Caesium-132 or Cobolt-60 are now available that would enable robot-deployed radiography. Using miniature robotic devices 104 with UT or EC imaging allows a constant surface pressure to be applied despite complex curved surfaces. All these modalities can be deployed in single-sided or -front-front mode (
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is further understood that the terms “front” and “back” are not intended to be limiting and are intended to be interchangeable where appropriate.
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 languages of the claims.
