INSPECTION DEVICE AND INSPECTION UNIT

Abstract

Inspection device for examining pipes (8) comprising a sensor holder (1) that can be rolled along the pipe (8) during operation and which, in a section running transversely to a pivot axis (2), is provided with a circumference (4) that is at least substantially circular and has at least one sensor unit (3), the sensor holder (1) comprising at least one, preferably several, stabilizing means (6) arranged along the circumference (4), as well as an inspection unit.

Description

INSPECTION DEVICE AND INSPECTION UNIT The present invention relates to an inspection device for examining pipes, comprising a sensor holder that can be rolled along the pipe during operation and which, in a section running transversely to a pivot axis, is provided with a circumference that is at least substantially circular and which has at least one sensor unit. Pipelines, particularly magnetic steel pipes, are used worldwide to transport substances such as oil, gas, water, or mixtures thereof. Over the lifespan of such a pipe, various defects can appear on its wall. These include signs of wear and fatigue, which can lead to long-term malfunctions. As a pipe ages, these defects naturally occur more frequently, which is why pipelines require more intensive monitoring. The most common method for inspecting pipes is using so-called smart scrapers, which, however, is not always feasible, depending, for example, on the pipe's geometry and layout. Therefore, spherical devices are used as an alternative to smart scrapers. Their compact design offers greater mobility within the pipe and, consequently, excellent flow characteristics. Spherical inspection devices of this type move irregularly within the pipeline due to the dynamics of the transported medium and the pipeline's path; they can jump, rotate, or slide around the three spatial axes. These irregular movements result in a very high level of effort in data interpretation, to the point of making it impossible due to excessively low signal-to-noise ratios. This applies both to the interpretation of defect data and to determining the location of the defects. This prior art is described, for example, in EP 2902690 B1. The objective of the present invention is to provide an inspection device with more stable running behavior. The objective is achieved by means of an object according to claim 1 as well as by means of an object according to claim 16. Advantageous embodiments are found in the dependent claims as well as in the following description. According to the invention, the sensor holder comprises at least one, preferably several, stabilizing means arranged along its circumference. During operation, the stabilizing means facilitate or enhance the movement of the inspection device in a direction at least substantially transverse to a selected axis of rotation and its rolling along the circumference. During operation, the rolling occurs particularly along the pipe axis, the axis of rotation being preferably substantially transverse to the pipe axis, at least when it forms an angle of + / - 10° with the pipe axis. An improvement in rolling behavior occurs, in particular, when the inspection device rolls more smoothly—that is, more uniformly or generally—around a circumference in the pipe, centered on the selected pivot axis, than around another circumference with an additional pivot axis, which is then positioned transversely or at an angle to the selected pivot axis. The device rolls specifically on the portion(s) of the inspection device that form the circumference. The stabilizing means are arranged in particular away from the axis of rotation, that is, within or on the outer circumference, eventually forming it and ensuring a more stable rolling of the inspection device by the force that comes from them or an impulse originating from it. Regardless of whether the sensor holder is substantially circular or ellipsoidal, the stabilizing means arranged along the circumference promote movement if, for example, the orientation of the device's axis of rotation is stabilized, for instance, by increasing a generated rotational impulse or by means of adhesion to the pipe wall. By these latter means, the gravitational movement of the inspection device within the pipe is supported along the 0 or 6 o'clock position. A circular circumference exists when, on a flat surface, the inspection device can roll along a circumference similar to a circle without acceleration peaks interfering with the measurement. A circumference similar to a circle is therefore either a perfectly circular circumference or, for example, an approximately circular circumference formed by a polygonal path. The same applies to a sphere-like shape, described later. An ellipsoid-like shape is a shape that deviates from an ellipsoid by exactly one ellipsoid or by a few ellipsoids, i.e., less than 10 cm, preferably less than 5 cm. The stabilizing means may constitute the circumference or be arranged close to the circumference; for example, the section that runs transversely to the axis of rotation may run through the stabilizing means, located in particular radially at a distance from the axis of rotation, or run along them. Preferably, stabilizing means include one or more weights positioned radially at a distance from the axis of rotation and / or one or more magnets positioned radially at a distance from the axis of rotation, with the respective magnetic field of the magnet(s) interacting with the pipe wall during operation. In particular, the magnets have a greater weight than the areas of the inspection device that are radially displaced with respect to the axis of rotation. While a weight already increases the generated rotational impulse and thus helps maintain the direction of the axis of rotation, one or more magnets on or along the circumference of the inspection device, in addition to potentially increasing the rotational impulse, at least increase the adhesion between the wall and the device, thereby greatly facilitating slip-free operation.During the rolling of the inspection device, the magnetizable material of the pipe becomes magnetized, and when the magnet is removed during rolling, it demagnetizes again. This generates eddy currents that counteract an increase in the device's operating speed, thus greatly improving its running performance. The magnets, which can also represent additional weight along the circumference, contribute to significantly more stable operation of the device, both due to gravity and magnetic interaction. Permanent magnets are preferably used as magnets. However, electromagnets can also be used, so that the intensity of the interaction with the pipe wall can be adjusted by means of a corresponding control device. In a permanent magnet configuration, the north-south orientation of the permanent magnets is preferably parallel to the axis of rotation, so that no forces are generated in the tangential direction of the circumference. Alternatively, or additionally, one, several, or all of the magnets configured as permanent magnets can be oriented radially with respect to the axis of rotation, with their north-south orientation, so that no corresponding tangential forces are generated either. This rotationally symmetric arrangement of the magnets in the stationary state does not generate tangential forces, allowing for easier rolling. Magnetic forces are only established during the device's rotation due to eddy currents induced in the pipe, which counteract the movement and slow the device's advance. Therefore, using a corresponding control device, a braking force can be adjusted, for example, based on the desired or predefined speed, or on a speed range, particularly when using electromagnets. In particular, the beads are arranged very close together or side by side along the circumference, a very close arrangement being understood as a distance between the beads, with or without setting, in particular < 5 cm, preferably < 3 cm. In particular, the beads are directly next to each other with or without setting. According to another advantageous embodiment of the invention, the magnet or magnets are delimited at least on one side by a crimp made of, and preferably composed of, a magnetizable material. Viewed from the direction of the axis of rotation, this crimp is preferably in the form of a circular ring and is magnetizable. In particular, this crimp may form the circumference. In this way, the magnetic field lines can be concentrated towards the wall, so that the magnetic flux is better introduced into the pipe wall. In particular, two ring-shaped metal discs can be used on the lateral sides of the magnets incorporated into the circumference of the device. Preferably, the sensor holder is configured in a shape similar to a sphere or ellipsoid, at least with respect to its envelope. In the case of an ellipsoidal or ellipsoidal envelope, the lengths of two half-shafts, particularly those of equal length, are preferably greater than the length of the third half-shaft located on the axis of rotation. The third half-shaft should preferably be between half and 100% of the length of one of the two additional half-shafts. This effectively prevents tipping, thus achieving improved flow capacity. In combination with stabilizing means, the device can adapt its envelope to the curvature of the pipe. This improves the orientation of the medium flow along the pipe axis and simultaneously creates space for potential drive elements. In the present case, an ellipsoid-like shape is therefore a rotationally symmetric shape that can roll stably through a pipe and in which the length of the third semi-axis is not chosen so short that the device quickly tips over on its side. Through the stabilizing means themselves, which are configured in particular as mandrels, and in particular in combination with the shape of the inspection device, it is self-stabilizing and therefore rightes itself during its movement within the pipe, in case the inspection device has tipped over on its side. According to an alternative configuration to the variant of the invention in which it can be rolled through the pipe without support, the sensor holder, which is otherwise provided with an equally spherical or at least substantially ellipsoidal housing, can be attached and, in particular, rotatably mounted on a support element intended to support the inspection device against the pipe wall and which, in particular, at one end comprises the sensor holder and at the other end is configured to rest against the pipe wall, preferably with a rolling wheel that is smaller in circumference compared to the circumference of the sensor holder. The axis of rotation of such a rolling wheel and that of the sensor holder are preferably configured parallel to each other.This results in a particularly stable ride along the pipe in its 6 o'clock position, with the rolling wheel, which is made of polyurethane, preferably the front wheel in the direction of travel. An elongated support that joins the two ends of the support element may additionally accommodate a sensor, an energy accumulator and / or electronics. Preferably, the circumference consists of at least one damping element made at least partially from synthetic material, preferably with pressure sensors and temperature sensors. The device's rotation can be used to perform odometer measurements. The distance traveled can be determined from the rotation angle and the device's diameter. The rotation angle can be measured, for example, by measuring the direction of gravity with a gyroscope and / or an acceleration sensor and / or by detecting contact of at least one point of the device with the wall. Furthermore, the centrifugal acceleration, which can be measured with the gyroscope or acceleration sensor, can also be used to calculate the device's speed and thus estimate its distance traveled. Potential acceleration peaks that can be measured with the acceleration sensor can be used for weld bead detection. Since the position of the weld beads is often known, these signals can be used to correct or determine the device's position. To detect contact with the wall at a specific point on the inspection device, according to one variant of the invention, a Hall sensor can be used as a magnetic field sensor. Upon contact with the wall, the magnetic field changes significantly, especially in the area of ​​closest proximity of the sensors to the wall. This can be detected by the Hall sensor as it rolls past the device's position. From the signal curve recorded during this process, in addition to the exact point of contact, a corresponding contact time can also be detected. The device's rotation can be calculated based on the detected events. The contact time is detected in the corresponding electronics, either in the control unit or in the sensor itself, and can then be calculated either on the inspection device itself or subsequently based on the detected signals. Alternatively or in addition to a Hall sensor, in another configuration of the invention, at least one coil may be integrated into a device according to the invention. A magnetic field detected in the coil can then also be used to calculate the rotation of the device. Sound sensors, for example, in the form of a hydrophone, can be used to transmit information to the device or to emit sound into the pipe wall, particularly for locating the device or transmitting other types of information. This information can also be received from outside the pipe wall or by sound sensors or microphones integrated into the pipe wall. The sound sensors can also be ultrasonic sensors, which are used for integrity testing. In particular, according to another embodiment, the device according to the invention can also incorporate EMAT sensors, i.e., electromagnetic transducers that can generate ultrasound without liquid coupling media, through electromagnetic interactions within the pipe wall. Magnets incorporated as stabilizing means can be used to create the magnetic field necessary for generating the ultrasound.Preferably, the EMAT sensors are then arranged in a displaced manner in different directions with respect to the magnets, in the direction of the rotation axis of the inspection device. Pressure and temperature sensors can be used to correct the data obtained. According to the invention, the inspection device may include at least one camera. In this case, the camera's position can be advantageously determined by an acceleration sensor on the inspection device, allowing images to be captured at predefined camera positions. Alternatively or additionally, the camera may record image sequences, i.e., videos. Preferably, several cameras are evenly spaced around the circumference. Alternatively or additionally, the inspection device also includes one or more cameras with their primary field of view along the axis of rotation. For example, and in particular, a continuous view of the inside of the pipe can be automatically generated. By combining images, video recordings can be made for a specific camera position, as if the camera were not rotating with the device. In a variant where the recording time is linked to the device's position, uniform coverage of the pipe wall is achieved regardless of the device's operating speed. By integrating the acquired data, such as the distance within a pipe, image or video recording can be automatically triggered or activated by an external signal at a specific position. For example, the device's position can be linked to the start of a series of measurements in which, for instance, one or more ultrasonic sensors initiate a measurement.After the operation, the data set stored in the device can be evaluated for a specific sensor position. Alternatively, in isolated variants, a data set can also be evaluated during the operation using appropriate transmission methods, such as through a pipe or cable. Preferably, lighting means, particularly in the form of LEDs, are assigned to a respective camera. Advantageously, the inspection device according to the invention comprises a generator with a generator coil wound with several turns such that the magnetic flux through the individual turns constantly changes as the device rotates. In this way, an electrical voltage is induced, which is used to charge any rechargeable batteries present and to power the electronics. In particular, the inspection device is configured to record an image and / or a sequence of images based on a position determined by a sensor. In particular, the inspection device is provided with at least one propulsion element that extends away from the axis of rotation. This element may consist, for example, of plates or webs arranged to the left and right of the stabilizing means with respect to the axis of rotation. The construction is configured, in particular, such that the same load capacity is achieved when the device rotates 180° around the axis of rotation. This ensures that the device can continue operating without restriction in the event of an unexpected 180° rotation. Specifically, the plates are configured to generate a downstream torque around the axis of rotation. This can be achieved, for example, by means of corresponding helical plates. To perform inspections, for example, at both the zero-hour and six-hour positions, in another embodiment, a device according to the invention is configured such that the sensor holder has weight elements that can be integrated by means of fillable cavities in the inspection device and / or in the sensor holder and / or an interchangeable support structure of variable medium density. In this way, a zero-hour or six-hour position of the inspection device can be set for a pipe containing a liquid medium. To avoid an unwanted transition from the inspection device to pipe branches, it can be widened by means of lateral stabilizers, for example, in the form of protruding arms or rudders. Several of the inspection devices according to the invention can also be coupled together to form an inspection unit to achieve the objective set out at the beginning. For this purpose, a central unit, for example in the form of a frame, connects several inspection devices such as those described above or below. A central unit of this type may have additional functional units, for example, an energy storage unit and / or a data memory unit. Integrated into a classic scraper, the device can also be used as an odometer and / or as a measuring unit for a conventional scraper. Further advantages and details of the invention can be found in the following description of figures, showing schematically: Figure 1 shows an inspection device according to the invention in a perspective view, Figure 2 shows the object according to Figure 1 in a cross-sectional representation, Figure 3 shows a partial view of a part of the object according to Figure 1, Figure 4 shows an inspection unit according to the invention, Figure 5 shows a view of a circumference of a device according to the invention, Figure 6 shows another device according to the invention, and Figure 7 shows the object according to Figure 6 in a cross-sectional representation, depicted in a pipe. The features of the embodiments according to the invention, which are explained below, may also be the subject of the invention individually or in combinations other than those shown or described, but always at least in combination with the features of an independent claim. Where appropriate, functionally identical parts are provided with identical reference numbers. An inspection device according to the invention for examining pipes in which a fluid, in particular water and / or oil, is transported, has a sensor holder 1 that can be rolled along the pipe during operation and which, in a section running transversely to a pivot axis 2 (see Figure 5), is provided with a circular circumference 4. Figure 5 shows only the outer circumference in a cross-sectional representation without additional functional parts of the inspection device. Furthermore, the inspection device or sensor holder 1 has several stabilizing means 6 arranged along the circumference 4, which in this case are configured as permanent magnets with a north pole N and a south pole S positioned side by side. During operation, the inspection device moves in a direction F (Figure 3), which corresponds to the longitudinal direction of the pipe 8. During this movement, the inspection device rolls along the inner side of the pipe 8. Due to the magnets located radially at a distance 2 from the axis of rotation, during operation, the magnetic field interacts with the pipe wall 10. The rolling on the inner surface of the pipe wall 10 and the resulting variations in the magnetic field generate eddy currents that counteract an increase in the speed of the inspection device in direction F. In this way, the rolling of the inspection device in the pipe 8 is carried out more uniformly. In this case, the permanent magnets are oriented parallel to the rotation axis 2 with their north / south orientation. The magnets, arranged very close together along the circumference 4, are delimited on both sides by an annular crimp 12 (Figure 2). These two crimps 12 can also form the circumference and, in particular, make contact with the pipe wall. Specifically, however, they direct the magnetic field towards the pipe wall 10, resulting in a stable interaction during operation. In the present case, the crimps 12, which in another configuration of the invention can also delimit the bar magnets in a single piece and in a U shape, are joined together or to a support structure 16 of the inspection device by means of fastening 14. The support structure 16 is substantially configured with two mirror-symmetric halves, each having a plate-shaped base on which hollow cylindrical sections 18 are arranged. Partially within these sections, as well as within a central cavity of the inspection device, is an electronic unit 20 comprising a control unit and / or a data memory and / or an energy accumulator and / or an acceleration sensor and / or a communication unit. The electronic unit may be sealed towards the open ends of the hollow cylindrical extensions. In this case, hydrophone-shaped sensors 22 are arranged at this end. The support structure of the sensor holder 1 further comprises propulsion elements 24 in the form of sheets that are configured in a single piece with the hollow cylinder 18 and the plate-shaped base and that generate flow resistance and ensure improved propulsion of the inspection device within the pipe. The device envelope has an ellipsoid-like shape, with the aforementioned ends configured with hydrophones and / or the area configured for contact with the pipe wall being additionally flattened, both in this and in other embodiments of the invention. In particular, the support structure 16 is made from a synthetic material, preferably polyurethane, and has damping properties to keep disturbances caused by possible vibrations as low as possible. Around the bearings, and also forming part of the circumference, is an annular damping element 26, made of a synthetic, elastic material. Its outer surface is positioned farther from the axis of rotation than the crimpings 12, which represent rolling elements. During operation, the damping element 26 is compressed, thus counteracting the magnetic attraction forces and providing damping. Furthermore, the bearings are protected against mechanical damage, and due to the increased surface friction, the device rolls more smoothly and uniformly, as slippage on the pipe wall is reduced. In the detailed view of Figure 3, in addition to the magnets or stabilizing elements 6 and the crimps 12, coils 21 of a generator are shown. During the device's rotation, an electrical voltage is induced in these coils, which is used to generate power. This allows the energy storage device to be charged or the device's power supply to be improved. The cavities 27 present inside the device can be filled by means of a pump system not shown in detail, in order to adapt the buoyancy of the inspection device in a medium 28 (see figure 4) in such a way that a respective inspection device rolls either as shown in figure 4 on the upper side of the pipe wall 10 or on the lower side of the pipe wall rollers 10. Both inspection devices shown in Figure 4 can be connected to each other by an optional central unit 30 shown in dashed lines, for example, in the form of a frame. Instead of a sensor unit 3, a camera not designated as a sensor for the purposes of this application may also be arranged in the inspection device, in particular a 2D or 3D camera, generating based on data from an acceleration sensor an image capture always in a certain relative position of the camera with respect to the pipe wall. According to Figures 6 and 7, another embodiment of the invention is provided with a support element 32 for supporting the inspection device on the side wall of the pipe, to which the sensor holder 1 is rotatably attached. At one end, the sensor holder 1 is attached to a segmented portion 34 in the previous embodiment, and at the other end, a rolling wheel 36 is provided for support against the pipe wall. The portion 34 serves to mount the sensor holder 1 by means of sliding bearings or roller bearings. The axes of rotation of the rolling wheel 36 and the sensor holder 1 run parallel and transversely to the longitudinal and running direction of the pipe. The rolling wheel 36 is the guide element of the inspection device, whose sensor holder 1 has drive elements 24 that run helically away from a rotation axis.This sensor holder 1 is also provided with a circular circumference 4 that is configured by crimps 12. As stabilizing means 6, lugs are arranged along the circumference. Depending on the embodiment, the guide wheel 36 may also be provided with lugs along its circumference. It is hereby stated that, as of this date, the best method known to the applicant for putting the aforementioned invention into practice is the one that is clear from the present description of the invention. NOVELTY OF THE INVENTION Having described the present invention, it is considered a novelty and, therefore, priority is claimed for the content contained in the following:

Claims

1. Inspection device for examining pipes (8) comprising a sensor holder (1) that can be rolled along the pipe (8) during operation and which, in a section running transversely to a pivot axis (2), is provided with a circumference (4) that is at least substantially circular and has at least one sensor unit (3), characterized in that the sensor holder (1) comprises at least one, preferably several, stabilizing means (6) arranged along the circumference (4).

2. Inspection device according to claim 1, characterized in that as stabilization means (6) one or more weights and / or magnets are provided, located radially at a distance from the axis of rotation (2), with a magnetic field of the magnet(s) interacting with a pipe wall (10) during operation.

3. Inspection device according to claim 2, characterized in that the north-south orientation of the sensors configured as permanent sensors runs parallel to the axis of rotation (2).

4. Inspection device according to claim 2, characterized in that the north-south orientation of the magnets configured as permanent magnets runs radially to the axis of rotation (2).

5. Inspection device according to one of the preceding claims 3 or 4, characterized in that the magnets are arranged very close together along the circumference (4).

6. Inspection device according to one of the preceding claims, characterized in that the magnet(s) are delimited at least on one side by a crimp (12) having a magnetizable material and, in particular, viewed in the direction of the axis of rotation (2), preferably having the shape of a circular ring and, in particular, being magnetizable and, in particular, constituting the circumference (4).

7. Inspection device according to one of the preceding claims, characterized in that the sensor holder (1) has a spherical or ellipsoidal envelope.

8. Inspection device according to claim 7, characterized in that, in the case of the ellipsoidal envelope, the lengths of two semi-axes, in particular of equal length, are greater than that of the third semi-axe located on the axis of rotation.

9. Inspection device according to any one of claims 1 to 6 above, characterized in that the sensor holder (1) is rotatably attached to a support element (32) which is provided to support the inspection device on the pipe wall (10) and which, in particular, at one end comprises the sensor holder (1) and at the other end is configured to rest on the pipe wall (10).

10. Inspection device according to one of the preceding claims, characterized in that the circumference (4) is constituted by at least one damping element (26) manufactured at least partially from synthetic material, preferably annular and / or elastic, and / or by at least one rolling element.

11. Inspection device according to claim 10, characterized in that a support structure (16) of the sensor holder (1) is made at least from this or other synthetic material.

12. Inspection device according to any of the preceding claims, characterized in that the sensor unit (3) of the inspection device has at least one sensor from a group comprising gyroscopes, acceleration sensors, magnetic field sensors, sound sensors, EMAT sensors, pressure sensors and temperature sensors.

13. Inspection device according to one of the preceding claims, characterized in that the inspection device has a camera and / or a generator with a generator coil.

14. Inspection device according to claim 12 and claim 13, characterized in that the inspection device is configured to capture an image and / or a sequence of images based on a position determined by a sensor.

15. Inspection device according to one of the preceding claims, characterized in that the inspection device has at least one propulsion element (24) that extends in particular away from the axis of rotation (2).

16. Inspection device according to one of the preceding claims, characterized in that the sensor holder (1) has a variable average density by means of fillable cavities (27) of the inspection device and / or by means of weight elements integrable into the sensor holder (1) and / or by means of an interchangeable support structure (16).

17. Inspection unit according to one of the preceding claims, characterized by a central unit (30) that is connected to one or more inspection devices according to one of the preceding claims.

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