The present invention refers to a self-propelling device, particularly for positioning probes, in non destructive testing.

In oil and petrochemical plants, one of the most important risk factors comes from the fact that most of the products in the apparatuses, in the piping and in the reservoirs are more or less corrosive.

This means that with time the initial thickness of the manufactured products gradually reduces through coz'rosion, combined with erosion due to the swirling flow of fluids. The designer normally takes the different theoretic values of corrosion which can appear in the various sections of the plant into account, entering in the calculation of the manufactured products an extra corrosion allowance and determining a minimum resistant thickness beneath which it must not drop and if it does, the portion involved must be repaired or replaced. In order to keep the aforementioned values under control and thus ensure that the manufactured products remain reliable over time, special apparatuses are used for non destructive testing, called thickness gauges with programmed operating cycles, specially designed to detect the thickness of metal materials. These types of tools use ultrasound technology and are in general made up of an apparatus provided with a screen or display and of an ultrasound-emitting probe which is manually placed in contact with the piece to be examined by the specialized worker, after having interposed a suitable coupling liquid between the probe and the piece to be examined.

The echoes produced by the ultrasound, or more simply, the simple decimal numeric value of the detected thickness, appear on the display of the apparatus.

Since the manufactured products to be tested, are generally at a height of over three meters, it is almost always necessary to use suitable lifting means, such as for example, ladders, platforms or scaffolding, in order to allow workers to access the zones to be tested.

When it is the case of using simple ladders to reach the zones to be examined, the cost of the tests is not affected in a particularly negative way compared to ground tests . On the other hand, when it is necessary to use lifting platforms, or even special scaffolding, the cost of such additional work could even be tens of times more than the simple ground test cost, without considering the natural intrinsic danger of scaffolding and the danger induced by its bulk, for example, in areas where possible fire- fighting means transit. Moreover, also detections carried out by workers on the upper surfaces or roofs of manufactured products such as reservoirs contribute towards increasing the danger of such operations, since the surfaces can collapse due to a reduced thickness caused by corrosion. The purpose of the present invention is that of avoiding the aforementioned drawbacks and in particular that of designing a self-propelling device for positioning probes for non destructive testing which is able to replace a worker in zones that are difficult to access or which are dangerous, whilst carrying out non destructive testing.

Another purpose of the present invention is that of providing a self-propelling device for positioning probes for non destructive testing which is able to easily run along the surfaces of a manufactured product with flat vertical walls or walls having a slight curvature like, in particular, reservoirs, distillation columns, reactors, chimneys and so on, without ever losing its grip. A further purpose of the present invention is that of making a self-propelling device for positioning probes for non destructive testing which can reduce the costs and danger of operations, making the use of special structures, such as lifting platforms or scaffolding superfluous.

These and other purposes according to the present invention are achieved by making a self-propelling device for positioning probes for non destructive testing as outlined in claim 1.

Further characteristics of the device are the object of the dependent claims . The characteristics and the advantages of a self- propelling device for positioning probes for non destructive testing according to the present invention shall become clearer from the following description, given as an example and not for limiting purposes, referring to the attached schematic drawings in which:

- figure 1 is a plan view from the top of a preferred embodiment of a self-propelling device for positioning probes for non destructive testing, according to the present invention; - figure 2 is a side elevational view of a preferred embodiment of a self-propelling device for positioning probes for non destructive testing, according to the present invention;

- figure 3 is a side elevational view of the probe- bearing means used in the self-propelling device for positioning probes for non destructive testing, according to the present invention.

With reference to the figures, a self-propelling device for positioning probes for non destructive testing according to the present invention is shown, wholly indicated with reference numeral 10. The self-propelling device 10 comprises a support structure 11 made up of two parallel shoulders lla connected to each other through a plurality of cross members. In the preferred embodiment illustrated, the support structure 11 comprises a front cross-member 23, an intermediate cross member 24 and two rear cross members 21, 22.

At least one probe 26 for non destructive testing and preferably one ultrasonic probe 26 are constrained to the structure 11 of the self-propelling device 10. Moreover, at least two coaxial motorized wheels 12, 13 are connected to the front of the structure 11 of the self-propelling device 10.

In the embodiment illustrated, both wheels 12, 13 are respectively coupled, through a toothed belts drive 14, 15, to a motor 16, 17, for example, a geared motor, which determines its motorization.

The two wheels 12,13 are of the magnetic type and preferably have a sandwich structure in which a plurality of internal disks 12a, 13a made from magnetic material are interposed in a coaxial manner between pairs of external flanges 12b, 13b made from a high resistance material. In the embodiment illustrated, the sandwich structure comprises two internal disks 12a, 13a totally interposed between three external flanges 12b, 13b.

Preferably, the external flange 12b, 13b has a grained surface in order to increase the friction against the surface of the manufactured products .

In a preferred embodiment, the disk made from magnetic material 12a, 13a is made from a neodymium magnet, whereas the external flanges 12b, 13b are made from magnetized steel .

The self-propelling device 10 also comprises, free sliding means 19 with a spherical configuration, positioned centrally with i-espect to the first rear cross member support 22 and thus equidistant from the shoulders 11a of the structure 11, connected to a first rear cross member 22 of the structure 11 itself. Such spherical sliding means 19 are preferably made from steel and are housed in a seat 20 made from insulating material, like for- example PVC (polyvinyl chloride) , in turn fixedly constrained to the first rear cross member 22 of the support structure 11 of the self-propelling device 10.

Interposed between the insulating seat 20 and the first rear cross member 22 there is a magnetic ring 18 for coupling the self-propelling device 10 with the manufactured product to be inspected.

In order to control the self-propelling device 10, a connector 25 is foreseen for the wired connection to the power supply and to the control interface supported by the second rear cross member 21 of the support structure 11. From the connector 25 a plurality of connecting cables (not illustrated) branch off which are suitable for transferring the power supply to the single motors 16,

17.

Moreover, also a tube for supplying a coupling fluid, for example water, which is conveyed up to the probe 26

(detail not illustrated) reaches the connector, in order to improve the transmission of the ultrasound to the manufactured product to be monitored.

The coupling fluid forms a thin film between the probe 26 and the surface of the manufactured product so that the ultrasound is propagated through such a fluid without passing through air thicknesses.

Otherwise, in an embodiment not illustrated, it is possible to equip the self-propelling device 10 with a battery and with an interface suitable for receiving radio controls and for converting them into a suitable signal for controlling the respective motors 16, 17.

In such a case, only the supply of the coupling fluid happens in a cabled manner. The probe 26 is constrained to the intermediate cross member 24 of the plurality of cross members 21-24 of the structure 11 through a probe-bearing element 27 having three degrees of freedom.

According to the present invention, the probe 26 is housed in a position interposed between the wheels 12,

13 and the free sliding means 19, ensuring, in such a way, that the probe 26 is always arranged up against the surface of the manufactured product .

In a preferred embodiment, the probe-bearing element 27 comprises a vertical shoe 27a pivoted onto the lower part of which are two arms 27b, constrained to the free end of which is the body of the probe 26 in a manner free to rotate around the axis defined by first pins 27c which connect such a body 26 to the arms 27b. Therefore, the probe 26 can translate vertically varying its relative height with respect to the structure 11, it can rotate around second pins 28 which connect the arms 27b to the shoe 27a, modifying its inclination with respect to the plane of the shoe 27a, and it can rotate around the axis defined by the first pins 27c, thus being able to rotate on itself. The probe 26 is also maintained coupled with the manufactured product through suitable elastic means (not illustrated) which act upon the probe- bearing element 27 by pushing it away from the structure 11. The operation of the self-propelling device 10 for positioning probes for non destructive testing is as follows .

The actuation of the motors 16, 17 determines the movement of the respective drives 14, 15 and thus of the wheels 12, 13 in this way making the self-propelling device 10 advance.

An actuating power difference of the motors 16, 17 allows the direction of movement to be slightly modified. The free sliding means 19 do not block the movement of the self-propelling device 10 following it independently from the direction of movement.

The magnetic and friction properties of the wheels 12, 13 and of the magnetic disk 18 positioned at the free sliding means 19 allow the self-propelling device 10 to advance along vertical surfaces without ever losing grip. Therefore, the probe 26 also grips perfectly onto the surface to be analyzed. Moreover, thanks to the exceptional grip of the self- propelling device, it is not necessary to use additional safety measures, such as for example a safety line to be fastened at the top of the manufactured product to be inspected, and therefore there is no need for personnel to manage such safety measures .

From the description made, the characteristics of the device object of the present invention should be clear, just as the relative advantages should also be clear. Finally, it is clear that the device thus conceived can undergo numerous modifications and variants, all of which are covered by the invention; moreover, all the details can be replaced by technically equivalent or better performing elements. In practice the materials used, as well as the sizes, can be any according to the technical requirements.