ODOMETER AND INSPECTION AND / OR CLEANING DEVICE

Description

[0001] The present invention relates to an odometer for distance measurement in an inspection and / or cleaning device, wherein the odometer comprises a carrier designed to roll on a surface, which is rotatably arranged about an axis of rotation in a holder of the odometer and has a plurality of magnets arranged circumferentially around the axis of rotation. The odometer also includes a magnetic field sensor for generating signals produced by rotation of the magnets of the carrier. Furthermore, the invention relates to an inspection and / or cleaning device comprising such an odometer.

[0002] CN 102621218 A discloses an odometer, or odometer wheel, which has a plurality of magnets arranged circumferentially around the axis of rotation of a wheel-shaped carrier. These magnets are passed by a magnetic field sensor, so that a corresponding measurement signal is generated depending on the rotation of the wheel. From the analysis of this signal, the distance traveled can be deduced using the circumference of the odometer wheel. However, a disadvantage of this device is that, for example, in heavily contaminated oil pipelines, slippage of the wheel often occurs. In such a case, the measurement results become inaccurate. CN 102621218 A therefore proposes arranging several such odometers in an inspection and cleaning device. This complicates the evaluation due to data fusion, and at the same time, the existing odometers can also exhibit the same problems due to slippage.Furthermore, the arrangement of multiple odometers increases the cost of the device, makes it heavier, and reduces the usable installation space.

[0003] US Patent 6,125,955 describes the design of a magnetic wheel for a vehicle, particularly a four-wheeled vehicle, capable of traveling over a ferromagnetic surface. Each wheel comprises a series of adjacent, ring-shaped sets of permanent magnet poles.

[0004] The article "Tubulo - A train-like miniature inspection climbing robot for ferromagnetic tubes" by Patrick Schoeneich et al. (2010 1ST INTERNATIONAL CONFERENCE ON APPLIED ROBOTICS FOR THE POWER INDUSTRY, ISBN: 978-1-4244-6633-7) presents a train-like, climbing inspection robot for ferromagnetic tubes. The robot can be equipped with magnetic wheels featuring a central magnet with guides on both sides.

[0005] The subsequently published WO 2021 / 156433 A1 discloses an inspection device for pipelines which has a sensor carrier that can be rolled through a pipeline.

[0006] The object of the present invention is to design an odometer and an inspection and / or cleaning device with such an odometer in such a way that the length of the distance traveled can be determined more accurately and at the same time the number of odometers is kept as low as possible.

[0007] The problem is solved by articles according to claims 1, 13 and 14. Advantageous embodiments of the invention can be found in the dependent claims relating thereto and in the following description.

[0008] According to the invention, the support is designed to create a closed magnetic circuit with a magnet and the magnetizable wall of, for example, a pipeline. The magnets are arranged circumferentially around the axis of rotation of the support, and at the moment of closest approach of one of the magnets to the surface or wall of the pipeline, the magnetic field generates a strong attractive force between the wall and the magnet or support. This improves the adhesion of the odometer to the surface of the wall, thus increasing the frictional force that causes the wheel to rotate. Particularly with oil-coated inner surfaces of pipelines, this enables a more precise determination of the distance traveled. The magnetic attraction acts between the support and the wall and not in an axle bearing of the odometer. Therefore, for example, the pressure of the holder and the associated bearing friction in the axle bearing can be reduced.This applies not only to the use of odometers according to the invention in pipelines but also to their use on other magnetizable surfaces. The attractive forces generated by the magnets with the surface of the object being tested improve the rolling motion of the wheel-shaped carrier. The magnetic field sensor detects the magnetic field of the carrier's magnets as they pass by the sensor, particularly when there is no closed magnetic circuit with the wall. Furthermore, the amplitudes of the measurement signals can provide information about the condition of the odometer, especially regarding deformation or slippage of the wheel or carrier despite the magnetic attraction.

[0009] The odometers, specifically designed to attract a surface, reduce the bearing friction of the bearing(s) on the axis of rotation, which arises from the necessary pressure of the odometer wheel against the wall surface. In particular, less pressure can be applied, and the corresponding devices can be designed smaller. Furthermore, conventional odometers in inspection and / or cleaning devices can be replaced by odometers according to the invention, meaning that the contact forces are identical to those previously applied. The torque acting on the odometer, generated by the friction between the wheel and the surface, is thus based on a force that is at least partially determined by magnetic attraction.

[0010] There are several possible configurations of a closed magnetic circuit, for example, a horseshoe-shaped magnet. Advantageously, however, the carrier has at least one magnetizable guiding element that directs and, in particular, focuses the magnetic field of a given magnet. Such a guiding element is made, at least substantially, of a magnetizable metal, especially a ferromagnetic material, and can conduct the magnetic field between the opposite poles of two magnets. In particular, the magnetizable guiding element directs the magnetic field lines of a magnet toward the surface along which the odometer is moved and on which the carrier rolls.

[0011] Preferably, the individual magnets are arranged with their north-south orientations (NS orientations) at an angle of less than 15° to the axis of rotation and, in particular, parallel to the axis of rotation, so that the poles of the magnets are at least approximately, and preferably exactly, the same distance from the surface. A symmetrical arrangement aids the rolling of the wheel due to the resulting absence of imbalances. Preferably, the north-south orientations of magnets following one another in the circumferential direction are the same, so that no closed magnetic circuits are formed between successive magnets in the carrier and when using guiding elements.

[0012] In particular, the magnets should be positioned as close as possible to the wall being viewed within the support, while still being protected. For example, the magnets are positioned a maximum of 1 cm, preferably a maximum of 0.5 mm, away from the wall along the circumference of the support during operation.

[0013] Preferably, each magnet is associated with two guide elements, wherein the magnet is arranged parallel to the axis of rotation and the guide elements define the boundaries of each magnet on both sides in a direction parallel to the axis of rotation. Furthermore, the guide elements extend radially outwards with the wall to form a magnetic circuit, so that a U- or approximate horseshoe shape is formed in a cross-section along the axis of rotation through the magnet. In this shape, the magnet forms a portion close to the axis, and the guide elements represent the two legs of the "U" or horseshoe that point towards the surface of the pipe wall during operation. Preferably, the magnets are spaced 0.5 to 4 cm apart from the radial outer circumference of the support.

[0014] The U- or horseshoe-shaped design optimally directs the magnetic field lines to the surface, resulting in a magnetic connection and thus good interaction and attraction during operation. The guiding elements are located laterally to the magnet and extend radially towards the outer circumference of the support. They also act as stabilizing elements, since rotation of the support accelerates a mass located radially outwards relative to the axis of rotation. The guiding elements can be designed, in particular, as circular segments or discs that define the boundaries of the magnets and, together with any circumferential coatings or sheathing, form the circular circumference of the support when viewed from the side, in the direction of the axis of rotation.

[0015] Preferably, the magnets are designed such that at the moment of greatest approach of the respective magnet to the surface of the wall, the component of rolling friction caused by the magnetic attraction of the magnets outweighs that caused by a contact force exerted by the holder, i.e., that the magnetic attraction force determines the rolling friction at least substantially.

[0016] Extensive calculations have shown that the magnetic field strength of at least one of the magnets on the outer circumference of the support, as well as during operation in the wall, is at least 5 kA / m, preferably at least 10 kA / m, and particularly at least 50 kA / m. The corresponding magnetic field strengths of the odometer are therefore at least one, more likely two or three orders of magnitude higher than those used in the prior art solely for determining the revolutions of the wheel or support.

[0017] According to the invention, the magnetic field strength of at least one of the magnets on the outer circumference of the carrier in air and at a distance from the wall is at most 500 kA / m, in particular at most 200 kA / m, and even more specifically at most 100 kA / m. Odometers according to the invention are preferably usable in a range between 50 and 100 kA / m, especially for pipelines in which oil is transported. A magnet is considered to be at a distance from the wall when, during operation, it is at least a quarter of a rotation of the carrier from its position closest to the wall, and in particular when the magnet has its greatest distance from the wall.

[0018] The above considerations regarding magnetic field strength take into account the course of the magnetic field due to the conductive elements.

[0019] Preferably, the magnets are designed to be relatively movable relative to the magnetic field sensor arranged on or in a holder of the odometer, so that the evaluation of the signals is comparatively simple. The magnetic field sensor is also preferably arranged eccentrically with respect to the axis of rotation and, in particular, circumferentially on the carrier. For example, it is attached in or to a base of the holder between two support arms of the holder that holds the carrier. According to a further embodiment of the invention, an odometer is provided circumferentially on the carrier with a flexible sheath, wherein a flexible sheath is one that, depending on the existing magnetic field strength, undergoes a reduction in thickness in the radial direction of at least 10%, preferably at least 30%, and particularly at least 40% during unwinding.This compression or elastic deformation of the material occurs when the magnet, during the rolling of the carrier, reaches its closest point to the surface. After further rolling, the material can then expand back to its original thickness. This further removes any magnetically adhering dirt or grime that may have been run over, thus reducing the magnetic field strength. Due to the simultaneous magnetic field present in the wall, magnetically adhering dirt tends to stick to the wall, keeping the carrier and the resulting wheel clean. Specifically, the radial coating is a maximum of 2 mm thick, and in particular, a maximum of 1 mm thick.

[0020] Additionally, the wheel-shaped carrier can have a circumferential, non-magnetic coating on at least one side. Preferably, non-magnetic coatings are present on both sides of the magnet and / or associated conductive elements, creating a distance from the magnetized conductive elements or the magnet itself, thus reducing the adhesion of material and dirt. The coating can be annular or disc-shaped on both sides of the magnet, relative to the axis of rotation, so that it provides shielding, at least in the outer circumferential region where dirt is most likely to adhere.

[0021] Should any magnetically adhering dirt persist that could not be prevented by the aforementioned measures, a further advantageous embodiment of the invention allows the odometer to have a cleaning element designed to scrape off the adhering magnetic dirt. This cleaning element should act on at least an area circumferentially located on an outer surface of the carrier, and thus be arranged at a short distance of < 5 mm from an outer surface of the carrier. Accordingly, it could, for example, be a scraper that removes dirt circumferentially or along the sides of the carrier, so that the attractive force between the carrier / odometer and the surface can be further optimized during a measurement run. The same applies to odometer variants that do not have a casing or coating.The cleaning element is preferably made of a non-magnetic and non-magnetizable material, for example polyurethane.

[0022] The initial problem is further solved by a cleaning and / or inspection device comprising a previously or subsequently described odometer, in which a pressure device acting on the holder is additionally provided for positioning the carrier on a surface, and which is characterized in that, during operation, the pressure force of this pressure device acting in an axle bearing is less than the attractive force caused by a near-surface magnet. Accordingly, the frictional torque of the carrier is essentially caused by the magnetic interaction of the magnets. A magnet is considered near the surface at the moment of its smallest distance to the surface of the wall during a measurement run.

[0023] In addition, an inspection and / or cleaning device according to the invention comprises a computer device for receiving the signals from the magnetic field sensor. This computer device can be part of a computer device continuously connected to, and in particular integrated into, the inspection and / or cleaning device, or it can be part of an arrangement not continuously connected to the cleaning and / or inspection device. In particular, the signals or measurement data of the magnetic field sensor of the odometer are stored in a memory of the computer device during a measurement run. Additionally, the computer device can evaluate the signals of the magnetic field sensor during the measurement run and, if available, couple further measurement data from an inspection device with corresponding position or distance data.

[0024] Preferably, the inspection and / or cleaning device also includes an connectable analysis device configured to detect wear, deformation, and / or slippage of the carrier by means of a signal profile. Wear of the carrier is indicated in particular by a deviation from the original amplitudes of the measured signal, while slippage of the wheel is recognizable by a spacing of the amplitudes (in terms of time).

[0025] Further advantages and details of the invention can be found in the following description of the figures. The schematic representation shows: Fig. 1 shows an object according to the invention in a side view, Fig. 2 shows the object after Fig. 1 in a front view, Fig. 3 the object Fig. 1 in a perspective view, Fig. 4 measurement data of an object according to the invention, Fig. 5 a sectional view of an object according to the invention, Fig. 6 another object according to the invention, Fig. 7 another object according to the invention, Fig. 8 the object according to Fig. 7 in a side view, Fig. 9 another object according to the invention.

[0026] Individual technical features of the embodiments described below can also lead to further developments according to the invention in combination with the features of at least the independent claims. Where appropriate, functionally equivalent parts are provided with identical reference numerals.

[0027] An odometer 2 according to the invention is generally designed to roll on a surface 4 of a wall 5, for example a pipeline. For this purpose, a rollable carrier 6, typically in the shape of a wheel, held by a holder 8, rolls on the surface 4 in the direction R. Via a magnetic sensor 12 (cf. Fig. 3 During operation, signals are generated by magnets rotating around a rotation axis 10 of the odometer 2 and, in an embodiment of the invention as an inspection and / or cleaning device, are stored in an associated storage unit of a computer device 30. The maxima and minima measured in the magnetic field sensor 12 generally result from the sequence of successive magnets 12 with the same north-south orientations running parallel to the rotation axis 10.

[0028] The carrier 6 of the odometer 2 is designed to form a closed magnetic circuit with the surface 4 and for this purpose has guiding elements 14 which are arranged laterally next to a respective magnet 11 in the direction of the axis of rotation 10 and which are indicated by arrows 13 ( Fig. 5 The magnetic circuit is formed by the guide elements 14. The magnetic field of a respective magnet 11 is directed towards and, in particular, focused on the surface 4. This results in strong attractive forces between the carrier 6 and the surface 4, provided the latter is at least partially composed of a magnetizable material, which counteracts slippage of the carrier 6 during rolling. This improves the distance measurement performed by the odometer and the position determination of the inspection and cleaning device based on the signals generated by the magnetic field sensor.

[0029] The holder 8 is typically attached to an inspection and / or cleaning device 28, which is pushed through a pipeline by a medium via propulsion elements, for example in the form of cups or discs 32. In particular, the holder 8 is resiliently supported by a pressure device 24 against a central body 25 of the inspection and / or cleaning device 28, also referred to as a pig (cf. Fig. 9 ).

[0030] The embodiments shown here are provided with a total of sixteen magnets 11, which are arranged circumferentially and relatively far towards the outer circumference of the respective carrier 6 between guide elements 14 ( Fig. 3 The carrier of the odometer 2 is held by two support arms 15, which converge in a base of the holder 8. The magnetic field sensor 12 is located in this base and is thus positioned circumferentially on the side of the carrier 6, which is circular in a side view.

[0031] The movement of the magnets 11 along the magnetic field sensor 12 during operation ideally results in a Fig. 4 The signal waveform shown, with a total of eight minima and eight maxima per half revolution U of the carrier 6, resulting from the successive magnets of the same orientation. A complete revolution U over 360° of the circular carrier can thus be resolved by seventeen maxima or minima, each marked with a small circle ( Fig. 4 The further curve lying below the curve with the many minima and maxima, with only one maximum and only one minimum, would arise in odometers typically used in the prior art, which have only one rotating magnet in the carrier. In comparison, the accuracy of the measurement of the odometer 2 according to the invention is significantly improved.

[0032] Depending on the distance A between successive maxima and minima, partial slippage of the support or odometer 2 can be inferred, which is also readily identifiable due to the large number of measurements taken per revolution. Furthermore, the change in the height H of the maxima and minima provides information about the wear and / or deformation of the wheel-shaped support 6.

[0033] According to one embodiment of the invention, the magnetic attraction between magnets 11 of the carrier 6 and the wall of a pipeline is greater than the force exerted by pressing the carrier against it. In particular, the magnetic attraction reduces the bearing friction caused by pressing the carrier 6 against the surface of a wall via the holder. This, in turn, smooths the rolling motion of the odometer 2 on the surface 4.

[0034] Additionally, a sheathing 16 can be provided for the support 6, which increases the friction between the wheel-shaped support 6 and the wall 5. The sheathing 16 is particularly flexible, so that, as shown in Fig. 6 As illustrated, during operation, the magnet 11 is compressed at the point of smallest distance between magnet 11 and wall 5 and then expands again. This increases the distance between the magnetic dirt present on the outside of the coating sheath 16, i.e., magnetically attracted particles in the pipeline, and the magnets 11, so that a force Fd can act on the dirt. This force is determined by centrifugal forces and / or by a magnetic attraction from the wall generated by magnetization through the odometer, and causes the dirt 20 to no longer adhere magnetically to the carrier 6.

[0035] Additionally, a circumferential, non-magnetic coating 18 can be arranged on both sides of the magnets and, in particular, the guide elements 14, which also produces the same effect as the sheathing 16 described above. Due to the additional spacing, less dirt can accumulate on the guide elements 14, so that any dirt 20 tends to adhere more to the pipe wall 5 ( Fig. 7 and 8 Additionally, a cleaning element 22 can be arranged on the holder 8, which mechanically scrapes magnetically adhering dirt from the surface of the casing ( Fig. 8 ).

[0036] An inspection and / or cleaning device according to the invention comprises, in addition to a previously described odometer 2, a pressure device 24 for positioning the carrier 6 on a surface of the wall 5 of a pipeline. This inspection and / or cleaning device also includes the computer device 30 for receiving the signals from the magnetic field sensor 12, arranged in a central body 25. After the measurement run, the data stored in this computer device 30 are transferred to an analysis device, which is configured to infer deformation and / or slippage of the wheel-shaped carrier 6 by means of the signal profile and, in particular, the changes in the height H of the measured signals and the amplitude intervals A.

Claims

1. An odometer for distance measurement in an inspection and / or cleaning device, wherein the odometer comprises a carrier (6), which is provided for rolling on a surface (4) of a wall (5), in particular of a pipeline, is arranged in a holder (8) of the odometer (2) so as to be rotatable about an axis of rotation (10) formed during operation and has a multiplicity (11) of magnets, which are arranged circumferentially around the axis of rotation (10), and wherein the odometer (2) has a magnetic field sensor (12) for generating signals produced through rotation of the magnets (11), characterized in that the carrier (6) is designed to generate a closed magnetic circuit with a respective magnet (11) and the magnetizable wall (5), wherein the magnetic field strength of at least one of the magnets (11) at the outer circumference of the carrier in the air and away from the wall is a maximum of 500 kA / m.

2. The odometer as claimed in claim 1, characterized in that the carrier has at least one magnetizable conducting element (14), which conducts and in particular focuses the magnetic field of a respective magnet (11).

3. The odometer as claimed in claim 2, characterized in that the magnets are arranged with their North-South alignments at an angle of smaller than 15° to the axis of rotation (10) and in particular parallel to the axis of rotation (10).

4. The odometer as claimed in claim 3, having at least two conducting elements, characterized in that the conducting elements (14) delimit a respective magnet (11) on both sides in the direction parallel to the axis of rotation (10) and extend radially outwards to form a respective magnetic circuit with the wall (5).

5. The odometer as claimed in one of the preceding claims, characterized in that the magnets (11) are designed to generate an attractive force with the wall (5), which at least substantially determines a rolling friction.

6. The odometer as claimed in one of the preceding claims, characterized in that the magnetic field strength of at least one of the magnets (11) at the outer circumference of the carrier during operation and in the wall is at least 5 kA / m, preferably at least 10 kA / m and in particular at least 50 kA / m.

7. The odometer as claimed in one of the preceding claims, characterized in that the magnetic field strength of at least one of the magnets (11) at the outer circumference of the carrier in the air and away from the wall is a maximum of 200 kA / m and in particular a maximum of 100 kA / m.

8. The odometer as claimed in one of the preceding claims, characterized in that the magnets (11) are designed so as to be movable relative to the magnetic field sensor (12) arranged on or in a holder (8) of the odometer (2).

9. The odometer as claimed in one of the preceding claims, characterized in that the magnetic field sensor (12) is arranged eccentrically with respect to the axis of rotation (10) and in particular at the circumference of the carrier (6).

10. The odometer as claimed in one of the preceding claims, characterized in that the carrier (6) is provided with a flexible sheathing (16) at the circumference.

11. The odometer as claimed in one of the preceding claims, characterized in that the wheel-shaped carrier (6) has a circumferentially extending, non-magnetic coating (18), at least on one side.

12. The odometer as claimed in one of the preceding claims, characterized in that it has a cleaning element (22), which is provided for scratching off adhering magnetic dirt and acts at least on a region located at the circumference of an outer surface of the carrier (6).

13. An inspection and / or cleaning device, comprising an odometer as claimed in one of the preceding claims, and a pressing device (24) acting on the holder (8) to position the carrier (6) on a surface (4), in particular of a pipeline, characterized in that a pressing force (24) which acts in an axle bearing during operation is lower than an attractive force produced by a magnet (11) which is close to the surface.

14. An odometer arrangement having an odometer as claimed in one of the preceding claims, and in particular as claimed in claim 13, having an EDP device (30) for receiving the signals of the magnetic field sensor (12).

15. The odometer arrangement as claimed in claim 14, characterized by an analysis device, which is designed to infer a deformation and / or a slipping of the carrier (6) with the aid of a signal curve.