DEVICE AND METHOD FOR THE NONDESTRUCTIVE TESTING OF A COMPONENT

Abstract

Provided is a device for nondestructive testing of a component, including a main body, test probes held on the main body, at least two displacement-indicator apparatuses held on the main body, each displacement-indicator having a displacement-sensing element, which is movably held on the main body, each displacement-indicator being designed to output a movement signal in response to the displacement-sensing element thereof being moved relative to the main body, which movement signal contains information about the instantaneous velocity of the movement of the displacement-sensing element relative to the main body or from which movement signal can be derived, and a displacement-indicator evaluation unit connected to the displacement-indicator apparatuses and designed and configured to receive movement signals from the displacement-indicator apparatuses during operation and to determine which displacement-indicator apparatus has the displacement-sensing element moving the fastest to output the movement signal of the displacement-indicator apparatus having the displacement-sensing element moving the fastest.

Claims

1. A device for a non-destructive testing of a component, the device comprising: a main body, which for the non-destructive testing of the component to be inspected is designed to be moved along the component; a plurality of test probes held on the main body for the non-destructive testing of the component, which are designed to generate scanning signals and to acquire measurement signals; at least two displacement-indicator devices held on the main body for determining position coordinates associated with the acquired measurement signals, each displacement-indicator device having a displacement-sensing element, which is movably supported on the main body and being arranged such that the displacement-sensing element can be brought into contact with a surface of the component to be inspected, each displacement-indicator device being configured to output a movement signal in response to the displacement-sensing element thereof being moved relative to the main body, the movement signal containing information about an instantaneous velocity of a movement of the displacement-sensing element relative to the main body or from which the movement signal can be derived; and a displacement-indicator evaluation unit, which is connected to the at least two displacement-indicator devices and is designed and configured to receive movement signals from the at least two displacement-indicator devices during operation and to determine, either continuously or at specified time intervals, which displacement-indicator device has a fastest moving displacement-sensing element, and to output the movement signal of the displacement-indicator device having the fastest moving displacement-sensing element for assignment to measurement signals acquired with test probers.

2. The apparatus as claimed in claim 1, wherein the at least two displacement-indicator devices are designed to output TTL signals as movement signals, and the displacement-indicator evaluation unit is designed and configured to count phase changes of the TTL signals output by the at least two displacement-indicator devices and/or through comparison of the TTL signals of the at least two displacement-indicator devices to determine when a phase of a TTL signal of one displacement-indicator device matches a phase of a TTL signal of another displacement-indicator device.

3. The device as claimed in claim 1, wherein exactly two displacement-indicator devices, each with one displacement-sensing element, are provided.

4. The device as claimed in claim 2, wherein the displacement-indicator evaluation unit is configured in such a way that the displacement-indicator evaluation unit changes from the output of a TTL signal of the one displacement-indicator device to an output of the TTL signal of the other displacement-indicator device if a count of the phase changes has shown that in the TTL-signal of the other displacement-indicator device a larger number of phase changes occurs within a time interval than in the TTL signal of the one displacement-indicator device in the time interval and in addition, if the phase of the TTL signal of the one displacement-indicator device matches the phase of the TTL signal the other displacement-indicator device.

5. The device as claimed in claim 1, further comprising: a test probe evaluation unit separate from the main body, which is connected via cables to the test probes held on the main body and to the displacement-indicator evaluation unit, and the displacement-indicator evaluation unit is configured in such a way that the displacement-indicator evaluation unut always only outputs movement signals of the displacement-indicator device with a currently fastest moving displacement-sensing element to the test probe evaluation unit for assignment to measurement signals acquired with the test probes.

6. The device as claimed in claim 1, wherein the displacement-indicator evaluation unit comprises at least one programmable microcontroller, wherein the at least one programmable microcontroller has a printed circuit board, a microprocessor and/or a multiplicity of input/output connections, wherein the microcontroller is designed in particular as an Arduino board.

7. The device as claimed in claim 1, wherein the displacement-sensing elements are arranged at opposite end regions of the main body and/or the displacement-sensing elements are arranged on two sides of at least one test probe array formed by a plurality of test probes.

8. The device as claimed in claim 1, wherein the displacement-sensing elements are implemented as rollers, wherein the rollers are supported on the main body such that the rollers can each rotate about a rotational axis, wherein the arrangement is such that rotational axes of the rollers are oriented parallel to each other and/or the rollers are manufactured from or comprise a magnetic material.

9. The device as claimed in claim 1, wherein the main body is a fir-tree- or swallow-tail- or T-shaped profile and/or that the main body is designed hollow and the displacement-indicator evaluation unit and/or the test probes and/or the displacement-indicator devices are arranged in the hollow main body, wherein if the displacement-indicator devices are arranged in the main body, the distance-sensing elements project from the main body in some sections in order to be able to be brought into contact with the surface of a component to be tested.

10. The device as claimed in claim 1, wherein the test probes are eddy-current test probes, which each comprise or are formed by at least one coil, and/or ultrasonic test probes and/or optical test probes, which comprise at least one light source and at least one camera.

11. The device as claimed in claim 1, wherein the displacement-indicator evaluation unit is designed and configured for carrying out the method.

12. A method for a non-destructive testing of a component, the method comprising: providing a component to be inspected; providing a device for the non-destructive testing of the component, which comprises a main body and a plurality of test probes held thereon, which are designed to generate scanning signals and to acquire measurement signals, and at least two displacement-indicator devices held on the main body for determining location coordinates associated with acquired measurement signals, each displacement-indicator device having a displacement-sensing element, which is movably, supported on the main body and being arranged such that the displacement-sensing element can be brought into contact with a surface of the component to be inspected, each displacement-indicator device being designed to output a movement signal in response to the displacement-sensing element thereof being moved relative to the main body, the movement signal containing information about an instantaneous velocity of a movement of the displacement-sensing element relative to the main body or from which the movement signal can be derived, wherein the main body is displaced along the component in such a way that the displacement-sensing elements come into contact with a surface of the component and as a result of the displacement are set into motion, and during the displacement of the main body by means of the test probes scanning signals are generated and measurement signals are acquired, and movement signals are output by the displacement-indicator devices; and continuously or at predefined time intervals, comparing the movement signals of the displacement-indicator devices are compared with each other, and on a basis of the comparison it is determined which displacement-indicator device has a fastest moving displacement-sensing element, and the movement signal of the displacement-indicator device with the fastest moving displacement-sensing element is output for assignment to measurement signals acquired with the test probes.

13. The method as claimed in claim 12, wherein TTL signals are output by the displacement-indicator devices as movement signals, and phase changes of the TTL signals output by the displacement-indicator devices are counted and/or through comparison of the TTL signals it is determined when a phase of a TTL signal of one displacement-indicator device matches phase of a TTL signal of another displacement-indicator device.

14. The method as claimed in claim 12, wherein a device for the non-destructive testing of the component with exactly two displacement-indicator devices, each with a displacement-sensing element, is provided.

15. The method according to claim 13, wherein a change is made from the output of TTL signals of the one displacement-indicator device to an output of the TTL signals of the other displacement-indicator device if a count of the phase changes has shown that in the TTL-signal of the other displacement-indicator device more phase changes occur within a time interval than in the TTL signal of the one displacement-indicator device in the time interval and in addition, if the phase of a TTL signal of the one displacement-indicator device matches the phase of a TTL signal of the other displacement-indicator device.

16. The method as claimed in claim 12, wherein the device for the non-destructive testing of the component includes a test probe evaluation unit separate from the main body, which is connected via cables to the test probes held on the main body and to the displacement-indicator evaluation unit, and the displacement-indicator evaluation unit always only outputs the movement signal of the displacement-indicator device with the fastest moving displacement-sensing element to the test probe evaluation unit for assignment to acquired measurement signals.

Description

DETAILED DESCRIPTION

[0038] FIG. 1 shows an embodiment of a device according to embodiments of the invention for the non-destructive testing of a component in a purely schematic representation.

[0039] This comprises a hollow main body 1 made of plastic, which for non-destructively testing of a shaft coupler 2 to be inspected in accordance with the present example, only sections of which are shown in FIGS. 2 and 3, is to be displaced along the shaft coupler, specifically along a fir-tree shaped groove 3 provided therein for attaching a turbine blade not shown in the figures. The outer contour of the main body 1 is matched to the internal contour of the groove 3. In concrete terms, both the main body 1 and the groove 3 have a fir-tree-shaped profile of the same dimensions, so that the main body 1 can be inserted into the groove 3 in a form-fitting manner (cf. also FIGS. 2 and 3). The shape of the main body 1 and groove 3 results in a defined displacement direction, which is indicated in FIG. 1 by an arrow 4 and coincides with the trajectory of the curved groove 3.

[0040] On the main body 1 a plurality of eddy-current test probes 5 provided by coils is held, which are designed to generate scanning signals and to acquire measurement signals. In the present case these are arranged in a plurality of diagonal rows and form a test probe array 6, which as is apparent from the figure, extends over almost the entire extent of the main body 1 in the y-direction and only a part of its extent in the x-direction. The test probes 5 in the exemplary embodiment shown are arranged in the main body 1. Specifically, each test probe 5 is held in a through hole provided at an appropriate place in the main body wall. On the rear-facing side of the main body 1 in FIG. 1, another test probe array 6, not visible in the figure, is provided which comprises the same number of test probes 5, which are distributed in the same way. Since two test probe arrays 5 are provided, the shaft coupler 2 can be inspected in the region of the entire groove 3 in a test operation.

[0041] The device also comprises a test probe evaluation unit separate from the main body 1 in the form of a conventional eddy-current device 7. Each of the eddy-current probes 5 held on the main body 1 is connected to the eddy-current device 7 in the conventional way via a wire, not shown in the figure. The wires are bundled outside the main body 1 in the cable 8 visible in the figure, which feeds into the eddy-current test device 7. In FIGS. 2 and 3, for the purpose of simplifying the drawing the eddy-current device 7 and the cable 8 are not shown.

[0042] To enable a locational assignment between the measurement signals acquired with the eddy-current probes 5 and the location points on the groove surface, at which the test probe(s) 5 was or were positioned, to acquire the measurement signals additional location information of the main body 1 relative to the groove surface is needed. To obtain this the device comprises two displacement-indicator devices 9 for determining location coordinates associated with measurement signals, which in the example shown are arranged in the hollow main body 1. These are therefore shown with a dashed line in FIG. 1. In FIGS. 2 and 3 the displacement-indicator devices are not shown. Each of the two displacement-indicator devices 9 comprises a displacement-sensing element, provided in the present case by a roller 10. Each roller 10 is rotationally mounted on the base body 1 about a rotation axis 11, wherein the arrangement is of such a form that the rotation axes 11 of the two rollers 10 are oriented parallel to each other. As is apparent in the figures, the rollers 10 are arranged in such a way that sections thereof project from the base body 1, to be able to come into contact with the surface of the shaft coupler 2.

[0043] Of the rollers 10, as is apparent in FIG. 1, one is arranged on each side of the test probe array 6, specifically one—in relation to the defined displacement direction of the main body 1—in front of it, i.e. in FIG. 1 on the left, and one behind it in relation to the displacement direction, i.e. in FIG. 1 on the right of the array 6. With regard to the same position and structure of the test probe array 6 on the reverse of the main body 1 the same applies analogously.

[0044] Each of the two displacement-indicator devices 9 is designed, in response to the roller 10 thereof being rotated, to output a movement signal which contains information about the current speed of movement of the roller 10, or from which such a speed can be derived. In concrete terms, each of the displacement-indicator devices 9 is designed to output two TTL signals phase-shifted by 90° relative to each other, which is also referred to as a 2-phase TTL signal. To this end the displacement-indicator devices 9 comprise, in addition to the rollers 10, further mechanical and electronic components which are sufficiently well known from the known art and are not shown in the purely schematic FIG. 1.

[0045] Finally, the device according to embodiments of the invention comprises a displacement-indicator evaluation unit in the form of an Arduino board 12, which is arranged in the hollow base body 1 in exactly the same away as the displacement-indicator devices 9 and thus also shown with a dashed line. This is a microcontroller, which comprises a printed circuit board, a microprocessor and a plurality of input/output pins, including so-called interrupt pins, which are not visible in FIG. 1, as this only shows the Arduino board 12 in a purely schematic form.

[0046] Both displacement-indicator devices 9 are connected via suitable wires 13 to the interrupt pins of the board 12 and the transfer of the movement signals is carried out, in particular, via the interrupt pins. Using the interrupt pins, it is possible to react to events that occur in the movement signals.

[0047] The Arduino board 12 is also connected via a wire 14, which runs outside of the main body 1—together with the wires for the test probes 5—through the cable 8, to the eddy-current test device 7.

[0048] During a test procedure the displacement-indicator devices 9 transfer both their movement signals to the Arduino board 12 and the latter is designed and configured to identify at pre-defined intervals which displacement-indicator device 9 currently has the roller 10 that is moving fastest, and only the movement signal of the displacement-indicator device 9 with the currently fastest moving roller 10 is always output to the eddy-current device 7 for assignment to measurement signals acquired with the eddy-current probes 5.

[0049] In particular, the determination of which roller 10 is currently moving faster is carried out by means of a counter. If the roller 10 of the one displacement-indicator device 9 is faster, the value in a global variable is incremented. If the roller 10 of the other is faster, the same variable is decremented. Depending on whether the value is greater than 2 or less than −2, the respective faster moving displacement-indicator device 9 is selected. In order that the counter value does not run without limit, the counting interval in this case is limited to the numbers between −2 and 2. If a higher or lower waiting time is required in operation, this can be implemented flexibly by adjusting the counting interval.

[0050] In order to avoid step losses during the switchover process, the counting of the counter is subject to the additional condition that the two movement signals are the same. To this end, the two signals are directly compared. Only in the case of equality of all phases is the displacement-indicator device 9 with the faster roller 10 selected, which means the device switches over to output the movement signal of this roller to the eddy-current device 6. This is intended to avoid, e.g., an unwanted signal direction change, because the switching sequence in 2-phase TTL signals indicates the direction of rotation.

[0051] The above will become particularly clear from consideration of FIG. 4. This drawing shows a 2-phase TTL signal 15 with a first phase 16 and a second phase 17, shifted by 90° with respect to the latter, of the displacement-indicator device 9 on the left of FIG. 1 and a 2-phase TTL signal 18 with a first phase 19 and a second phase 20 shifted by 90 degrees with respect to this of the displacement-indicator device 9 on the right in FIG. 1, over the distance s. The roller 10 of the displacement-indicator device 9 on the left in FIG. 1, whose 2-phase TTL signal 15 is forwarded by the Arduino board 12 to the eddy-current device 5 as of the start of a measurement, is currently moving a little slower than that on the right, which can be seen from the larger distance between adjacent rising and falling edges in the signal 15.

[0052] At the onset of the first condition (see the related labeling in FIG. 4) the right-hand displacement-indicator device 9 has output two more edge changes than the left-hand one. From here on the phase equality is maintained. Only when the position labeled with “Condition 2” in FIG. 4 is reached does the phase equality exist. At this point the switchover occurs to the output of the 2-phase TTL signal 18 of the right-hand displacement-indicator device 9 instead of the left-hand one.

[0053] The resulting 2-phase TTL output signal 21 with a first phase 22 and a second phase 23, which from the start corresponds to the 2-phase TTL signal 15 of the left-hand displacement-indicator device 9 and from the switchover time corresponds to the 2-phase TTL signal 18 of the right-hand one, is also drawn in FIG. 4.

[0054] If the subsequent monitoring reveals at a later point in time that the roller 10 of the left-hand displacement-indicator device 9 is rotating faster than the right-hand one, the device switches back again, and so on.

[0055] For the purposes of implementing the foregoing a program with appropriate content is stored on the Arduino board 12.

[0056] To perform a non-destructive testing of the shaft coupler 2 in the area of the groove 3 for cracks, for example, the device shown in FIG. 1 is provided. The main body 1 is inserted from the right-hand side in FIGS. 1 to 3 into the groove 3, displaced in this groove and withdrawn from it again on the opposite side of the groove 3, not visible in the figures. In FIG. 3 the main body 1 is shown in the condition in which it is inserted roughly half-way into the groove 3.

[0057] As soon as the main body 1 is inserted so far into the groove 3 that the roller 10 of the left-hand displacement-indicator device in the figures comes into engagement with the component surface, the roller 10 is set into rotation by the displacement of the main body 1 in the groove 3, and as a result the associated displacement-indicator device 9 outputs a 2-phase TTL signal 15 corresponding to the speed as a movement signal to the Arduino board 12. Since at this point in time the roller 10 of the other displacement-indicator device 9 has not yet come into engagement with the shaft coupler 2 (cf. FIG. 3), this is not moved, hence it has a speed of zero, so that the 2-phase TTL signal 15 of the left-hand displacement-indicator device 9—as the faster of the two—is output from the Arduino board 12 to the eddy-current device 7. As soon as the eddy-current probes 5 reach the groove 3 (see also FIG. 3), these output measurement signals. Since the roller 10 of the left-hand displacement-indicator device is already in contact with the shaft coupler 2, associated location coordinates are available.

[0058] After a further insertion of the main body 1 into the groove 3 the second roller 10 also comes into engagement. If the first one moves—for example as a result of slip—slower than this latter, as described in more detail above, the device switches over to the signal 18 of the second displacement-indicator device 9 and this signal is forwarded to the eddy-current device 7. Even without slippage or the like, a change takes place in any case when the roller 10 of the left-hand displacement-indicator device 9 loses contact with the shaft coupler 2 and consequently no longer moves, because the main body 1 already projects by an appropriate distance out of the other side of the groove 3. But then the 2-phase TTL signal 18 of the right-hand displacement-indicator device 9 is still available and is forwarded by the Arduino board 12—as the then faster signal—to the eddy-current device 6. Since the right-hand displacement indicator is positioned behind the arrays 6 in the displacement direction, associated location information are available for all measurement data acquired with these.

[0059] As a result, all measurement data can be interpreted in a location-dependent manner. Uncertainties concerning the actual location of detected defects do not occur. In addition, inaccuracies as a result of slippage—at least over the region in which both rollers 10 are in contact in with the shaft coupler 2 in the region of the groove 3—are reliably avoided.

[0060] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the intention.

[0061] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.