Apparatus and method for inspecting technical equipment using a borescope

Abstract

The invention relates to a device (1) and a method for inspecting a technical installation (20) using a borescope. The device (1) comprises an elongated support element (2) which is guided in a shape-changing unit (10) and is repeatedly plastically deformable, wherein the shape-changing unit (10) comprises a guide element (13) which is fixed in its position for axially guiding the support element (2) at an output end (12) and an actuator element (14) which is embodied for axially guiding the support element (2), wherein the actuator element is movable in at least one direction perpendicular to the distance between the guide element (13) and the actuator element (14) in order to selectively apply a bending moment to the support element (2) guided by the guide element (13) and the actuator element (14), and wherein a borescope head (5) is arranged at an end of the support element (2) which projects from the output end (13) of the shape-changing unit (10). In the method, the elongated support element (2) is repeatedly plastically deformable and comprises a borescope head (3), which, during insertion into the technical installation (20), selectively pre-deforms its end to be inserted into the technical installation (20) in the region of an entry front to the technical installation (20) in order to thereby follow a specified path of the borescope head (3) within the technical installation (20).

Description

[0001] This invention relates to an apparatus and method for inspecting technical equipment using a pipe endoscope.

[0002] It is known in the prior art that pipe mirrors are used to inspect areas that cannot be directly viewed in technical equipment. These pipe mirrors can be introduced into the area in question through small openings and provide observation of areas that cannot be viewed directly via optical systems or, alternatively, by displaying video images recorded by a suitable sensor system at the top of the pipe mirror (also known as video pipe mirrors).

[0003] For example, when inspecting an aircraft engine, a ductwork is used to see inside the engine without having to disassemble it. Here, at least for individual areas of an aircraft engine (such as, for example, the combustion chamber), it is necessary or at least desirable to thoroughly assess and document that area.

[0004] To inspect the interior of the combustion chamber, a video duct mirror with a flexible axis that can be manually guided through the chamber is currently used. For this purpose, the flexible duct mirror is guided along the entire inner circumference of the combustion chamber and then slowly retracted. Images captured by the duct mirror are recorded during the retraction. The aim is to ensure that the entire perimeter of the typically annular combustion chamber is captured. If a potential problem location within the combustion chamber is thus identified, a special 3D duct mirror suitable for this purpose is used to manually capture a 3D image of the corresponding location.

[0005] However, because the duct mirror with its flexible axis is manually guided, a complete and reproducible record of the combustion chamber's condition is virtually impossible. Furthermore, subsequent 3D imaging, particularly of potential problem locations, is extremely expensive and time-consuming.

[0006] The object of the present invention is to provide an apparatus and method by means of which the inspection of technical equipment using a pipe endoscope can be improved.

[0007] This objective is achieved through the apparatus claimed in the first set of claims and the method claimed in the second set of claims. Advantageous developments are the subject of the dependent claims.

[0008] The present invention therefore relates to an apparatus for inspecting technical equipment using a pipe endoscope, the apparatus comprising a repeatedly plastically deformable and elongated support element guided in a deformation unit, wherein the deformation unit comprises a static guide element and an actuator element, the guide element being used to axially guide the support element at an outlet end, the actuator element being designed to axially guide the support element and being movable in at least one direction perpendicular to the gap between the guide element and the actuator element in order to selectively apply a bending moment to the support element guided by the guide element and the actuator element, and wherein a pipe endoscope portion is arranged at the end of the support element and extends from the outlet end of the deformation unit.

[0009] Furthermore, the present invention relates to a method for inspecting technical equipment using a pipe endoscope, preferably using an apparatus according to the invention, wherein a repeatedly plastically deformable and elongated support element has a pipe lens portion, and during insertion into the technical equipment, the support element selectively pre-deforms the end to be inserted into the technical equipment in a region prior to the entrance to the technical equipment, so as to thereby follow a predetermined path of the pipe lens inside the technical equipment.

[0010] Some terms used in conjunction with this invention will be explained first.

[0011] The elongated load-bearing element is "repeatedly plastically deformable" if, during deformation, the load-bearing element shows little or no signs of fatigue and essentially (i.e., especially except for the deformed elastic component) retains the shape achieved by deformation. As part of the desired deformation, during use of the device according to the invention, the load-bearing element is preferably deformed in multiple cycles, for example at least 20 cycles, more preferably at least 50 cycles, without any apparent signs of fatigue.

[0012] A plastically deformable "load-bearing element" is one that, when used correctly, is not only self-supporting but also capable of bearing, at least plastically, the load it is intended to bear under gravity without deforming independently.

[0013] In the present context, "axial guidance" refers to the guidance of an elongated load-bearing element that allows movement of the load-bearing element in its axial direction but prohibits movement in the radial direction. Thus, as part of the guidance, the angular state of the load-bearing element's axis and / or the rotational movement of the load-bearing element about its own axis are substantially unrestricted or limited only by a wide range of angles through axial guidance. However, depending on the use of the device according to the invention or the design of the axial guidance, it is also possible to prohibit individual or all such angular modifications.

[0014] The "pipeline lens section" is the portion of the pipeline mirror that ultimately defines the recording area of ​​the pipeline mirror. In the case of a purely optical pipeline mirror, this corresponds, for example, to the inlet surface of the pipeline mirror lens or the light guide that defines the final recording cone; in the case of a video pipeline mirror, this is the recording area of ​​the image capturing sensor provided for this purpose. Whether 2D image capture in the visible range, recording in the invisible range (e.g., the infrared range), and / or the capture of 3D data, such as by triangulation, is performed via the pipeline lens section is irrelevant here. The pipeline lens section can, in principle, be arranged on a rigid or flexible axis. However, a pipeline lens section without its own structural axis can also be arranged on another element (such as, for example, a carrier element).

[0015] The present invention recognizes that the inspection of technical equipment (such as, for example, gas turbines or aircraft engines, particularly complex structures) using a pipe mirror can be improved, and particularly can be performed in a reproducible manner, if the path followed by the pipe mirror during insertion can be influenced at least to some extent in open and / or closed control loops. According to the invention, for this purpose, the provided pipe mirror portion is arranged at the end of an elongated, repeatedly plastically deformable support element, which will ultimately be introduced into the technical equipment for inspection using the pipe mirror, the deformation unit being configured for controlled deformation of the support element as it is inserted into the technical equipment.

[0016] The deformation unit here includes a guide element for axially guiding the load-bearing element. Because of the axial guiding characteristic within the sense of the invention, it is ensured that the load-bearing element departs substantially from the defined position of the deformation unit. The device according to the invention can thus be easily arranged relative to a technical device used for inspection with a pipe mirror, such that the load-bearing element can be pushed into an opening in the technical device suitable for introducing the pipe mirror.

[0017] To achieve deformation of the load-bearing element, the deformation unit includes an actuator element through which the load-bearing element is also axially guided. Because the actuator element is capable of movement in at least one direction, preferably in any desired direction perpendicular to the gap between the guide element and the actuator element, a bending moment can be selectively applied to the load-bearing element to thereby deform it. The ability of the actuator element to move along a direction perpendicular to the gap between the guide element and the actuator element is independent of whether the actuator element is also capable of movement in a direction parallel to the gap or of corresponding radial and axial movement relative to the axis of connection (e.g., because the actuator element is capable of moving along a circular track or runway).

[0018] By applying a bending moment to the bearing element using a deformation unit, and thus influencing and specifying the deformation and shaping of the portion of the bearing element extending from the guide element when the bearing element is correspondingly pushed through the deformation unit, it is possible to predetermine the path taken by the pipe lens portion at the end of the bearing element (e.g., inside the technical equipment) when pushed into or through the deformation unit.

[0019] Preferably, in addition to selectively applying bending moment to the load-bearing element, the actuator element is designed to selectively apply torque to the load-bearing element. This can be achieved, for example, by selectively fixing the guide around the axis of the load-bearing element (see below) in the case of non-rotational axial guidance of the load-bearing element. Particularly in the case of non-rotationally symmetric load-bearing elements, additional deformation modes can be achieved by selectively applying torque.

[0020] The actuator element and / or static guide element preferably include a controllable locking device for selectively securing the position and / or angular state of the carrier element in the actuator element and / or guide element. Depending on the securing design, additional deformation modes can be achieved through corresponding selective securing, for example by implementing temporary clamping. In the case of a suitable locking device on the guide element, it is also possible to prevent temporary movement of the actuator element (e.g., deformation of the carrier element) from undesirably affecting the end of the carrier element extending from the device. The locking device can be designed, for example, as a two-finger gripper for the carrier element.

[0021] Particularly preferably, the actuator element is movable in the direction of the gap between the static guide element and the actuator element. In addition to providing further variations, particularly when locking devices are present on both the guide element and the actuator element, the ability to move in the direction of the gap between the static guide element and the actuator element can be used, wherein alternating locking at the guide element and the actuator element causes the carrier element to advance segment by segment from the outlet end of the device.

[0022] Alternatively or additionally, the guiding element and / or actuator element may include a plurality of guide rollers for the carrier element, some of which are preferably driven. The forward movement of the carrier element (optionally, also continuously) away from the exit end can be achieved by suitably actuating one or more roller drives.

[0023] To achieve additional deformation and / or to introduce the carrier element into the technical equipment for inspection using a pipe mirror within a defined path, a guide tube extending from the deformation unit for the passage of the carrier element can be secured to the guide element. This guide tube is preferably detachable and therefore substantially replaceable. The predetermined introduction of the carrier element into the technical equipment to be inspected can be reproducibly achieved via the guide tube, which can be specifically configured for inspection using a pipe mirror. Furthermore, even with continuous deformation of the carrier element depending on the design of the guide tube, the final shape of the portion of the carrier element extending from the guide tube can be significantly influenced by the deformation mechanism, because the elastic portion deformed by the guide tube returns to the shape of the carrier element achieved by the deformation mechanism after it leaves the guide tube. In the case of a non-rotationally symmetric carrier element, the angular state of the carrier element in the guide tube can also affect the final shape.

[0024] Preferably, a feeding mechanism is provided on the side away from the guide element. This feeding mechanism feeds the carrier element to the actuator element in a defined manner. The feeding mechanism is either fixed relative to the guide element or moves with the actuator element. By means of a corresponding feeding mechanism, the accuracy of the carrier element's deformation can generally be improved through the movement of the actuator element, because the potential influence of undefined feeding on the final deformation is eliminated.

[0025] The carrier element can include a probe unit in the area of ​​the duct lens section for determining the position and / or orientation of the duct lens section. The guide tube can be checked for adherence to a predetermined path via the corresponding probe unit. The probe unit can be designed to determine position using any known measurement principle (e.g., time-of-passage analysis of radio or optical signals transmitted and / or received by the probe unit). Position can also be determined based on image evaluation; for this purpose, the probe unit includes a suitable image-capturing sensor. The probe unit can also be designed to be integrated with the duct lens section.

[0026] The device preferably includes a control device for control purposes. Here, it is preferable to implement control taking into account the position and / or orientation information of the pipe lens section obtained via the probe unit or the pipe lens section. Using the corresponding position and / or orientation information, the actual state and / or orientation can be compared with a predetermined path, and if a deviation is found, appropriate countermeasures can be adopted, wherein the position and / or orientation information can be calculated via the probe unit or alternatively via the pipe lens section (e.g., by image detection or evaluation of the acquired 3D data).

[0027] The tube lens section can be rigidly connected to the free end of the carrier element, which eliminates the need for a separate tube lens shaft. "Rigid connection" here can include the ability to selectively disassemble for maintenance purposes. However, the tube lens section can also be part of a flexible tube lens guided through a suitable channel in the carrier element. In the case of a rigid connection to the carrier element, it is preferable that the connection has a degree of freedom of rotational movement about the axis of the carrier element, and that the rotation of the tube lens section about this axis can be controlled. In a suitable design with a rotatable connection, 360° panoramic recording is possible. When the flexible tube lens is pushed through the carrier element, the corresponding rotation can be achieved by rotating the tube lens section. Alternatively, the tube lens section can preferably be designed to capture a 360° panoramic view. This can be achieved, for example, by arranging a suitable number of image capturing sensors radially distributed.

[0028] The actuator element can comprise, preferably, a six-axis articulated arm robot and / or a hexapod robot (Stuart platform), wherein the axially guided position and / or state of the actuator element can be modified by the robot. All commonly required deformations of the load-bearing element can be achieved using a suitable robot.

[0029] Advantageously and therefore preferably, the guide tube is a composite material tube. The guide tube can include a core made of wound metal strip, wherein the metal strip is preferably aluminum strip and / or wound along its length. To maintain the dimensional stability of the guide tube after deformation, a plastic cover (preferably a polyethylene cover) is also preferably provided for the core. A protective covering (preferably a protective film) can be provided on the side of the core opposite the covering, such that the core is completely surrounded by the covering and the protective covering. As a result, a smooth surface on both the outer and inner sides of the guide tube is generally achieved. Furthermore, the risk of damage to components of the technical equipment to be inspected by using a tube endoscope in the event of (unintentional) contact with the guide tube is reduced. For example, prior to the priority date, suitable tubes bearing the trademarks "Dekabon" or "Synflex" from Eaton Corporation, USA, were available and are described in detail, for example, in U.S. Patent 4,216,802.

[0030] The pipe lens section can include an image capturing unit as part of a video pipe mirror. It can also be designed to capture 3D surface data, for example, through triangulation based on image data from two image capturing units arranged adjacent to each other.

[0031] The technical equipment used for inspection using a pipe endoscope is preferably a gas turbine and / or aircraft engine. The present invention has been shown to be particularly suitable for the precise inspection of these technical devices using a pipe endoscope.

[0032] To explain the method according to the invention, reference is made to the above embodiments relating to an apparatus designed to perform this method. Advantageous developments of the described apparatus also directly provide for advantageous developments of the method.

[0033] The invention will now be described by way of example with reference to the accompanying drawings, in which:

[0034] Figure 1 A schematic diagram of the use of the apparatus according to the invention for inspecting the combustion chamber of an aircraft engine using a pipe mirror is shown;

[0035] Figure 2 It shows Figure 1 A schematic diagram of the cross-section;

[0036] Figure 3 A schematic diagram of a first embodiment of the device according to the present invention is shown;

[0037] Figure 4a , Figure 4b A schematic diagram of a second embodiment of the device according to the invention is shown; and

[0038] Figure 5a , Figure 5b A schematic diagram of an alternative embodiment of the pipe lens section rigidly connected to the carrier element is shown.

[0039] The apparatus 1 for inspecting technical equipment 20 (i.e., the combustion chamber 21 of an aircraft engine) according to the present invention is used Figure 1 and Figure 2 The duct mirror is shown in the image. For clarity, only the combustion chamber 21 of the aircraft engine is shown here. However, the device according to the invention is particularly suitable for use when the combustion chamber 21 is installed in an aircraft engine.

[0040] The device 1 includes an elongated support element 2 that can be repeatedly plastically deformed, having a conduit lens portion 3 at its end 2', which is introduced into the combustion chamber 21. The support element 2 is a composite tube comprising a core made of aluminum strip wound along its length, an outer covering of polyethylene, and a protective film acting as a protective cladding on the inner side. The guide tube 3 is self-supporting or alternatively supports the conduit lens portion 3, such that it substantially maintains its achieved shape after plastic deformation without any external influence.

[0041] The supporting element 2 is guided through the deformable unit 10, the precise design of which will be achieved by means of... Figure 3Figure 4 is described in more detail in the following different embodiments. The carrier element 2 is deformed in a controlled manner by bending and twisting in the deformation unit 10 by the control device 11, and then the carrier element is drawn out at the outlet end 12 of the deformation unit 10 and introduced into the combustion chamber 21. For this purpose, the carrier element 2 is introduced into the combustion chamber 21 through the inspection opening 12 in a curved guide tube 4 that is detachably fastened to the outlet end 12, and is actually self-supporting beyond the point defined by the free end 4' of the guide tube 3, and is reproducibly able to reach that point. Here, reproducibility is also achieved in particular by the fastening mechanism 6, by which the device 1 is fastened relative to the inspection opening 22 on the technical device 20 in a clearly defined position and state.

[0042] The duct lens section 3 is rigidly connected to the support element 2 and includes an image capture sensor for capturing digital 2D images, ultimately producing a video duct lens. Integrated with the duct lens section 3 is a probe unit 5, by which the position and orientation of the duct lens section 3 can be calculated. The information obtained by the probe unit 5 is available to the control device 11 and fed into the control system of the deformation unit 10, ensuring that the duct lens section 3 moves substantially along a predetermined path 90 when the support element 2 is pushed into the combustion chamber 21. If deviations from this path 90 are detected, the control device 11 can counteract them by appropriately activating the deformation unit 10.

[0043] exist Figure 3 The text shows the ability to, for example, in... Figure 1 and Figure 2 The first exemplary embodiment of the device 1 used in the invention is shown in particular detail, wherein the deformable device 10 is also shown.

[0044] The deformable unit 10 includes a static guide element 13, which forms, in particular, an outlet end 12, at which, in this exemplary embodiment, a guide tube 4 is also arranged. A support element 2 is axially guided within the guide element 13 along a defined axis. The support element 2 is configured here as a tube through which a separate flexible conduit (not shown) can be guided.

[0045] In addition, an actuator element 14 is provided, which is arranged on the boom of the six-axis articulated robot 15. The actuator element 14 is also designed to axially guide the carrier element 2 and has a locking device in the form of a two-finger gripper 16, by means of which the position and state of the carrier element 2 relative to the actuator element 14 can be fixed in a controllable manner.

[0046] The feed mechanism 17 is located adjacent to the actuator element 14 on the side away from the guide element 13 and similarly on the boom arm of the articulated robot 15. By means of this feed mechanism, the carrier element 2 is fed to the actuator element 14.

[0047] With the aid of the six-axis articulated robot 15, the actuator element 14 can move relative to the guide element 13 in almost any manner, particularly in the direction of the gap between the static guide element 12 and the actuator element 14, and in the direction transverse to that gap, so that bending and torque can be applied to the area of ​​the carrier element 2 located between the guide element 12 and the actuator element 14. By means of a suitable temporary locking using the two-finger gripper 16 and the corresponding movement of the actuator element 14 using the articulated robot 15, the carrier element 2 can be gradually pushed out of the outlet end 12 of the deformable unit 10, and thus pushed into the technical device 20 for inspection using the pipe mirror (see...). Figure 1 and Figure 2 ).

[0048] The articulated arm robot 15 can be controlled by the control mechanism 11, optionally including the probe unit 5 (see...). Figure 1 The position and status information of the bearing element 2 are used to gradually push it out of the deformation device 10, and it is concluded that at this point... Figure 3 The shape of the carrier element 2 is shown in the example.

[0049] As in Figure 4a , Figure 4b The side view and perspective view show the ability to Figure 1 and Figure 2 A second exemplary embodiment of the device 1 used is shown. The carrier element 2 is not shown here.

[0050] Despite according to Figure 3 The exemplary embodiments may appear to differ significantly at first glance; however, both exemplary embodiments are based on the same inventive concept, and therefore, reference should be made to the above design for further information.

[0051] Figure 4a , Figure 4b The deformable unit 10 shown includes a static guide element 13 that forms the outlet end 12 of the deformable unit 10 and allows the guide tube 4 to be detachably fastened thereto.

[0052] The actuator element 14 is arranged on the hexapod 15' to axially fix the load-bearing element 2 and has a locking device in the form of a two-finger gripper 16. The hexapod can be controlled by the control device 11 so that the position and state of the actuator element 14 (in particular relative to the guide element 13) can be modified, so that bending deformation of the load-bearing element 2 (not shown) guided by the guide element 12 and the actuator element 14 can be obtained.

[0053] In the case of the deformation mechanism 10 in Figure 4, a locking device in the form of a two-finger gripper 16' is also provided on the guide element 13. If the bearing element 2 is locked in the guide element 12 and the actuator element 14 by the two locking devices 16, 16', torque can be applied to the bearing element 2 by the proper activation of the hexapod robot 15'. With these locking devices 16, 16' locked alternately, the bearing element 2 can be gradually pushed out of the outlet opening 12 of the deformation unit 10.

[0054] Figure 4a , Figure 4b The deformable unit 10 is implemented in a way that is lightweight enough to be carried by a person and has a handle 18, making it easy to operate. Also due to its light weight, the deformable unit 10 can be securely fastened to the technical equipment 20 used for pipe endoscopy without problems under any desired conditions. Figure 1 The aircraft engine shown.

[0055] If the pipe endoscope lens 5 (e.g.) Figure 1 As shown, the connection is rigidly arranged on the support element 3. In order to be free from the orientation of the recording cone of the tube lens section 3, the connection discussed can have the degree of freedom to rotate and move about the axis of the support element 2, wherein the tube lens section 3 rotates about the axis by a suitable drive. Figure 5a The diagram shows a corresponding design with a driven rotary joint 30 and an image capturing sensor that serves as a pipe mirror lens.

[0056] Alternatively, multiple image capturing sensors can be configured in the duct lens section 3 and arranged radially for capturing a 360° panoramic view. In this case, the rotating joint 30 can be omitted (see...). Figure 5b ).

Claims

1. An apparatus (1) for inspecting technical equipment (20) using a pipe endoscope, comprising an elongated, repeatedly plastically deformable support element (2), said support element being guided in a deformation unit (10), wherein, The deformation unit (10) includes a static guide element (13) and an actuator element (14), the guide element being used to axially guide the load-bearing element (2) at an outlet end (12), the actuator element being designed to axially guide the load-bearing element (2) and being movable in at least one direction perpendicular to the gap between the guide element (13) and the actuator element (14) to selectively apply a bending moment to the load-bearing element (2) guided by the guide element (13) and the actuator element (14), and wherein a pipe lens portion (3) is provided at the end of the load-bearing element (2) extending from the outlet end (12) of the deformation unit (10).

2. The apparatus according to claim 1, characterized in that, The actuator element (14) is designed to selectively apply torque to the bearing element (2).

3. The apparatus according to claim 1, characterized in that, The actuator element (14) and / or the static guide element (13) include controllable locking devices (16, 16') for selectively fixing the position and / or angular state of the carrier element (2) in the actuator element (14) and / or the guide element (13).

4. The apparatus according to claim 3, characterized in that, The locking device (16, 16') is configured as a two-finger gripper.

5. The apparatus according to claim 1, characterized in that, The actuator element (14) is movable in the direction of the gap between the static guide element (13) and the actuator element (14).

6. The apparatus according to claim 1, characterized in that, The guide element (13) and / or the actuator element (14) include a plurality of guide rollers for the carrier element (2).

7. The apparatus according to claim 6, characterized in that, Some of the multiple guide rollers are driven.

8. The apparatus according to claim 1, characterized in that, The guide tube (4) extending from the deformable unit (10) for the passage of the bearing element (2) can be detachably fastened.

9. The apparatus according to claim 1, characterized in that, A feeding mechanism (17) is provided on the side away from the guide element (13), by means of which the carrier element (2) is fed to the actuator element (14) in a defined manner, wherein the feeding mechanism (17) is fixed relative to the guide element (13) or moves together with the actuator element (15).

10. The apparatus according to claim 1, characterized in that, The carrier element (2) includes a probe unit (5) in the region of the pipe lens section (3) for determining the position and / or orientation of the pipe lens section (3).

11. The apparatus according to claim 1, characterized in that, A control device (11) is provided for controlling the components (15, 16, 16') of the deformable unit (10).

12. The apparatus according to claim 11, characterized in that, The control device (11) takes into account the position and / or orientation information of the pipe lens section (3) obtained via the probe unit (5) or via the pipe lens section (3).

13. The apparatus according to claim 1, characterized in that, The duct lens section (3) is rigidly connected to the carrier element (2) or is part of a flexible duct lens that is guided through a suitable channel in the carrier element (2).

14. The apparatus according to claim 1, characterized in that, The actuator element (14) includes a six-axis articulated arm robot (15) and / or a hexapod robot (15'), wherein the axially guided position and / or state of the actuator element (14) can be modified by the robot (15, 15').

15. The apparatus according to claim 1, characterized in that, The bearing element (2) is a composite material tube.

16. The apparatus according to claim 15, characterized in that, The composite tube comprises a core, a plastic covering, and / or a protective covering on the inner side, wherein the core is made of aluminum strip and / or wound along its length.

17. The apparatus according to claim 16, characterized in that, The plastic covering is a polyethylene covering.

18. The apparatus according to claim 16, characterized in that, The protective coating is a protective film.

19. The apparatus according to any one of claims 1 to 18, characterized in that, The duct lens section (3) includes an image capturing unit as part of a video duct lens, and / or the technical device (20) is a gas turbine or an aircraft engine.

20. A method for inspecting technical equipment (20) using a pipe endoscope, employing the apparatus according to any one of claims 1 to 19, wherein, The elongated and plastically deformable support element (2) has a duct lens portion (3), and during insertion into the technical device (20), the support element selectively pre-deforms the end of the support element to be inserted into the technical device (20) in the region before the entrance to the technical device (20), thereby following a predetermined path of the duct lens portion (3) inside the technical device (20).

21. The method according to claim 20, characterized in that, The pre-deformation includes bending deformation and torsional deformation.

Images