NL2018403B1

NL2018403B1 - An electrically controlled transducer arrangement for remote, non-destructive inspection of metallic surfaces and an object comprising such transducer arrangement.

Info

Publication number: NL2018403B1
Application number: NL2018403A
Authority: NL
Inventors: Leendert Oostdijk Jacob
Original assignee: Zeeland Refinery N V
Priority date: 2017-02-21
Filing date: 2017-02-21
Publication date: 2018-09-21

Abstract

An electrically controlled flexible transducer arrangement for remote, non-destructive inspection and monitoring of a metallic surface, such as a metallic surface of a storage tank or pipe. The arrangement comprises an array of electromagnetic acoustic transducers, each transducer being arranged for nondestructive inspection of part of the surface to be inspected. A flexible electric contact layering, comprising a plurality of electrically conductive tracks for transferring electric power and exchanging control and measuring signals of a transducer. And a signal processing arrangement, for controlling the transducers for automatically performing the non-destructive inspection and for processing measuring signals of the transducers. The transducer arrangement may comprise a flexible electric power generation layer comprising a plurality of thermo-electric power generator modules and/or a plurality of photovoltaic modules, for providing electric power to the transducers and signal processing arrangement.

Description

Technical Field

The present disclosure generally relates to the field of non-destructive inspection or examination of metallic structures of objects and, more particularly, to a transducer arrangement for non-destructive inspection of the material properties of metallic or ferro-magnetic surfaces of objects, such as bulk storage tanks or vessels and associated piping that are subjected to corrosion and wear causing a deterioration of the mechanical properties of such an object.

Background

Metallic objects such as storage tanks, vessels or containers for holding gasses or liquids, whether or not at a pressure substantially different from ambient pressure, are generally installed in the open air and/or underground, as a consequence of which the metal surfaces of these objects are subjected to deterioration by corrosion, wear and other damaging. Dependent on the substance to be hold by a tank or container and the temperature of such substance, the metal surfaces of the tank or container may also be damaged from inside the tank or container, causing material loss and hence wall or shell thinning, for example. For safety reasons, periodic inspection or examination of the material properties of the outer metal walls of these objects is required.

In particular for storage tanks holding dangerous liquids or gases, such as fuels or extremely flammable substances or substances that provide a severe health risk in case of leakage or the like, non-destructive inspection, NDI, or also called non-destructive examination, NDE, techniques are preferred as these techniques do not permanently alter the material properties of an object to be inspected.

NDI or NDE methods for inspecting metallic surfaces are known in practice, and may include the use of special transducer or scanning devices and visual inspection, for example.

Visual inspection, both from the outside and/or the inside of an object, is rather time and resource consuming, while damages like microcracks or checking, caused by corrosion, fatigue or strain, or under deposit, for example, are difficult to detect from a visual inspection. Underground storage tanks and piping can anyhow not be visually inspected at the outside.

Electromagnetic acoustic transducers, EMATs, are proven for the detection of various types of surface deterioration due to corrosion, and operate without the need for a interface agent between the transducer and the surface to be inspected. EMATs provide also reliable measuring results in case of scaling or other deposits at the surface to be inspected.

Present transducers or scanners for inspecting the material properties of the metallic or ferro-magnetic surfaces of storage tanks, for example, have to be moved across the tank. For rather small vessels, the transducer or scanner may be moved manually above or at a surface to be inspected. However, in practice, bulk storage tanks having diameters and heights running from about a few meters to a few tens of meters require so-called crawlers that are equipped with the transducer or scanner. Dependent on the type of crawler and/or transducer used, this type of inspection may need costly scaffolding or rope equipment and manual support for guiding and moving the crawler across the vertical wall of a storage tank, for example. Although such measures may not be required for crawlers equipped with a driving mechanism for traversing a tank wall, such crawlers still require manual steering and control of the crawler, which likewise is resource and cost consuming.

Summary

It is an object of the present disclosure to provide for an automated non-destructive inspection, NDI, or non-destructive examination, NDE, of metallic surfaces of objects, such as metallic or ferro-magnetic walls of storage tanks and associated piping, either installed in the open air or partly or totally underground.

In a first aspect there is provided an electrically controlled flexible transducer arrangement for remote, non-destructive inspection of a metallic surface, in particular a metallic surface of a storage tank or pipe, the arrangement comprising:

- an array of electromagnetic acoustic transducers, EMATs, each transducer being arranged for non-destructive inspection of part of the surface to be inspected,

- a flexible electric contact layering, comprising a plurality of electrically conductive tracks for transferring electric power and exchanging control and measuring signals of a transducer of the array of transducers, and

- a signal processing arrangement, for controlling the transducers for automatically performing the non-destructive inspection and for processing measuring signals of the transducers.

The mechanically flexible transducer array arrangement presented is not limited to particular dimensions and can be designed for covering part of or for completely covering a metallic surface to be inspected. Due to its flexible, layered structure, the transducer arrangement can be excellently applied at curved or otherwise non-flat surfaces, such as cylindrical walls and curved roofs or bottoms of storage tanks and piping, for example.

By the on-board signal processing arrangement, the transducer arrangement may operate fully automatically either in an on-line or in a stand-alone modus, not requiring manual support. Accordingly, the transducer arrangement according to the present disclosure facilitates a fully automated, relatively quick and adaptable periodic or regular remote inspection of large metallic surfaces, in order to comply to several national and/or international safety requirements, for example.

It will be appreciated that the present transducer arrangement is in particular advantageous for use at large storage terminals, such as storage terminals for oil, fuel and gases, having up to one thousand or even more bulk storage tanks, saving many hours of manual inspection support.

Besides the aspect of significant cost savings, the transducer arrangement provided may be used for inspection of surfaces that can not be visually inspected or inspected by manually operated inspection devices, such as underground or otherwise hidden surfaces, for example walls of storage tanks or containers that comprise outer thermal isolation. Accordingly, for providing enhanced safety, the present solution increases the possibilities of installing objects that require regular inspection underground or otherwise covered, such as metal containers for storing nuclear waste or other dangerous substances.

The present transducer arrangement fits perfectly in the present need for networked, remote automated monitoring of objects, for early warning, maintenance and artificial intelligence applications, for example.

The transducer arrangement, in an embodiment thereof, is comprised of commercially available EMATs, wherein the transducers and the processing arrangement are directly mounted at the flexible contact layering, for example by soldering or the like.

In another embodiment of the transducer arrangement, the transducers are integrated in a flexible substrate layer, and the substrate layer comprises electric surface contact patches electrically connected to the transducers for electrically surface contacting of a respective conductive track of the electric contact layering.

The electric contact layering is fixed to the flexible substrate layer, either by gluing or otherwise adhering the contact layer to the substrate, for example by tightly covering the arrangement in a cover of a flexible plastic, electrically insulating material.

In a further embodiment, the transducers of the transducer array are comprised of a magnetic component part and an oppositely arranged inductive coil component part, wherein the flexible substrate layer is comprised of a first flexible substrate layer comprising the inductive coil component part and a second flexible substrate layer, arranged at the first substrate layer, comprising the magnetic component part of a transducer.

The magnetic component part may advantageously comprise a flexible magnetic substance, such as magnetic flakes, magnetically directed to provide a plurality of adjacently arranged permanent magnets having a magnetic field in a required direction. The electric coil component part may advantageously be comprised of a plurality adjacent electrical coils, such as coils comprised of electrically conductive tracks arranged at a flexible electrically insulating substrate layer.

The electric contact layering provides for both the transfer of control and measuring signals to a respective transducer or group of transducers, for activating the operation thereof and transfer of the output signals provided, under the control of the signal processing arrangement.

Separation of the signalling and power contact lines is provided, in an embodiment, in that the electric contact layering is comprised of a single layer of a flexible electrically insulating material, having a first surface comprising electrically conductive tracks arranged for transferring the measuring signals, and a second surface, opposite the first surface, comprising electrically conductive tracks arranged for transferring the electric power to the transducers.

In another embodiment of the present transducer arrangement is the electric contact layering comprised of a first layer of a flexible electrically insulating material comprising electrically conductive tracks arranged for exchanging the control and measuring signals with the transducers, and a second layer of a flexible electrically insulating material comprising electrically conductive tracks arranged for transferring the electric power to the transducers and an electrically conductive shielding layer.

By separating the electric contact layering for exchanging control and measuring signals and power with the transducers, on the one hand the design freedom of the signalling layer increases, such that same may be designed for addressing and locating an individual transducer or a group of transducers of the array, for example by providing separate row and column addressing signal lines, in case of a regular matrix type array of transducers, and measuring signal lines. On the other hand, for powering of the transducers, the power lines may be dimensioned such to have a sufficient low resistance in order to avoid excessive or undesirable electric losses and heating of the arrangement. However, some heating may be beneficial or required in order to eventually evaporate any moisture penetrated in the transducer arrangement. The electrically conductive shielding layer may provide both an electric mass contact for powering of the transducers and external shielding of the electromagnetic radiation provided by the transducers when in use.

It will be appreciated that in the embodiment having separate electric contact layers, the conductive tracks may also be provided at both surfaces of a respective layer, provided that the tracks of the layers do not come into electric contact with each other. To this end, the conductive tracks may be covered by electrical insulating paint or the like, provided of course at those positions where an electrical contact with a transducer is required.

The layered transducer arrangement is to be applied at the surface to be inspected in a manner to avoid the inclusion of moisture, oxygen or other substances causing or promoting corrosion of the surface. To this end, the transducer array or the first substrate layer comprising the inductive coil component part of the transducer arrangement may be glued or otherwise fixedly adhered to the surface to be inspected.

To avoid moisture from reaching the surface, in particular for the inspection of underground surfaces or surfaces in the open air, in an embodiment of the transducer arrangement, at least one of the electric contact layering and the substrate layer, i.e. the first and/or second substrate layer, is a moisture proof flexible epoxy layer. Suitable epoxy resins for the purpose of the present disclosure are wellknown in practice.

The transducer arrangement may powered in a traditional way, by applying electric mains power, for example, whether or not through an intermediate transformer or power supply, for example.

In a further embodiment of the present disclosure, the transducer arrangement comprises a flexible electric power generation layer, arranged at the electric contact layering, and comprising a plurality of thermo-electric power generator modules, arranged for generating and transferring electric power to the transducers and the signal processing arrangement by the electric contact layering. To maintain flexibility of the transducer arrangement, the power generator modules are either constructed from mechanically flexible material or in case of rather rigid power generator modules, the dimensions and mutual spacing of the power generator modules are selected such that the transducer arrangement as a whole allows for bending and curvature.

This embodiment is based on te insight that, in case of monitoring or inspecting surfaces of storage tanks or the like containing substances that produce heat, such as with pressure tanks or vessels, or storage tanks that contain high viscous substances that need to be heated up for transport thereof, the wall of the storage tank will adapt the heat of the substance and will become warmer than ambient temperature. Hence this heat difference can be used for generating electricity for powering of the transducer arrangement using thermo-electric power generator modules such as modules based on the well-known Peltier effect, for example.

This type of transducer arrangement is also excellently suitable for use with storage tanks holding substances that require a storage temperature above ambient temperature, to which end the outer walls of the storage tank comprise outer thermal wall isolation. The transducer arrangement is then advantageously placed between the metal wall of the storage tank and its wall insulation.

In an alternative embodiment, or additionally, the transducer arrangement comprises a flexible electric power generation layer, arranged at the electric contact layering, having a plurality of photovoltaic modules, arranged for generating and transferring electric power to the transducers and the signal processing arrangement by the electric contact layering. Again, to maintain flexibility of the transducer arrangement, the photovoltaic modules are either constructed from mechanically flexible material, so-called flexible thin-film photovoltaic modules, or in case of rather rigid photovoltaic modules, the dimensions and mutual spacing of the photovoltaic modules are selected such that the transducer arrangement as a whole allows for bending and curvature thereof.

Photovoltaic power generation modules or cells can be advantageously used for inspecting or monitoring surfaces in the open air, where solar rays can incident at the transducer arrangement. It will be appreciated that, for example, in the case of a bulk storage tank in open air, the embodiment of the transducer arrangement comprising photovoltaic or solar cells can be advantageously applied at the side of the storage tank where solar energy is available, whereas at other parts or walls of the storage tank that are in the shadow formed by a building or other storage tank, for example, an embodiment of the transducer arrangement without electric power generation layer may be applied. The transducers and signal processing arrangement of the latter embodiment may than receive power from the embodiment comprising the electric power generation layer.

It will be appreciated that the embodiments comprising an electric power generation layer do not require the installation of and investment in an external power supply or mains, which is very advantageous for large terminals comprising a few tens or hundreds of storage tanks. Also in case of inspection of containers having explosive or otherwise easy inflammable substances, an on-board power supply is to be preferred for safety reasons. Further, in case of storage tanks that are surrounded by a bunding, also called a bund wall, for receiving the substance of the storage tank in case of an unintended escape from the storage tank, the integrated electric power generation layer avoids power cables to cross the bund wall.

The mechanically flexible electric power generation layer may be glued or otherwise fixedly adhered to the electric contact layering and/or the substrate layer.

In a further embodiment the transducer arrangement comprises a plurality of strain gauge devices, arranged for measuring strain on the surface to be inspected, wherein the electric contact layering is arranged for electrically contacting the strain gauge devices to the signal processing arrangement. Strain gauge devices for the purpose of the present disclosure are known in practice. In an embodiment of the transducer arrangement the electric coils of the inductive coil component part of the transducers may be advantageously arranged as strain gauge devices.

The transducer arrangement according to the present disclosure may comprise various signal processing equipment, either general purpose or specifically adapted signal processing devices. In particular, for digital data processing, in embodiment the signal processing arrangement comprises at least one digital data processor integrated in the transducer arrangement. Digital processing devices, in particular mechanically flexible digital processing devices for use in the transducer arrangement are known and available in practice.

The signal processing arrangement is particularly programmed and constructed such that adjacent EMATs are operated in conjunction. That is, one EMAT operates in a transmitting or sound generating mode and an adjacent or a plurality of EMATs adjacent to the one EMAT operate in a receiving mode, such to inspect or monitor across the whole surface to be inspected. It will be appreciated that different modes of operation are possible, such as operating two EMATs in a transmitting mode, for example. The term adjacent is not limited to directly neighbouring EMATs.

In particular for remote operation, in an embodiment of the transducer arrangement the signal processing arrangement comprises at least one data communication device arranged for exchanging measuring and control data with remote data processing equipment by at least one of wired and wireless data communication.

The data communication may be arranged in accordance with any of known data communication techniques and protocols, such as Ethernet, Wi-Fi, Li-Fi, mobile communication technologies termed 3G, 4G or 5G, for example, etc. In the case of wireless communication devices, at a site comprising one or a plurality of objects to be inspected or monitored, radio or lightwave access or base stations may be installed, for data exchange with a transducer arrangement of one or a plurality of the objects.

Wireless data communication is in particular advantageous in case of storage tanks that are surrounded by a bunding or bund wall, for example.

In a second aspect there is provided an object comprising an outer metallic surface, such as a storage tank, in particular a bulk storage tank for holding gas or liquids, or piping, for example, comprising a transducer arrangement according to any of the previous embodiments attached to the outer metallic surface. In particular a storage tank at which the transducer arrangement is fixedly attached or applied at part or the whole surface to be inspected. It is noted that for the inspection of piping, for example, the transducer arrangement may be temporarily applied at the pipe, for example.

The above disclosed and other aspects of the present disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. In this description and the drawings, like reference numerals designate constructively identical or functionally identical components.

Brief Description of the Drawings

Figures 1, 2, 3 and 4 schematically shows, in a perspective and exploded view, embodiments of a transducer arrangement in accordance with the present disclosure.

Figures 5 schematically shows, in a perspective and exploded view, an embodiment of a prior art electromagnetic acoustic transducer, EMAT, for nondestructive surface inspection of metal surfaces.

Figure 6 schematically shows, in a perspective and exploded view, a transducer arrangement comprising electromagnetic acoustic transducers, EMATs, in accordance with an embodiment of the present disclosure.

Figure 7 schematically shows a storage tank comprising a transducer arrangement in accordance with the present disclosure, and data communication equipment.

Detailed Description

In Figure 1, reference numeral 10 indicates an electrically controlled flexible transducer arrangement for remote, non-destructive inspection of a metallic surface in accordance with an embodiment of the present disclosure.

An array 12 of electromagnetic acoustic transducers, EMATs, 13 is arranged, for example in the form of a rectangular matrix. Each transducer 13 is arranged for non-destructive inspection of a different part of a surface to be inspected. The transducers 13 comprise electric contact terminals, such as surface mount contact terminals (not shown). The transducers 13 of the array 12 are either constructed from mechanically flexible material, or in case of rather rigid transducers 13, the dimensions and mutual spacing of the transducers 13 are selected such that the array 12 as a whole is mechanically flexible, i.e. allows for bending and curvature, thereof.

For electrically connecting the transducers 13, a flexible electric contact layering 14 is provided. The electric contact layering 14, in the embodiment shown, is comprised of a single flexible layer of electrically insulating material having a plurality of electrically conductive tracks 15, 16 arranged at one side of its surface, and a plurality of electrically conductive tracks 17 arranged at an opposite other side of the surface of the contact layer, and shown by dash-dot lines. The conductive tracks 15, 16, 17 are, for example, made of copper and etched or deposited at the flexible layer of electrically insulating material in a manner that is well known in the art of printed circuit boards, PCBs, for example.

The electric conductive tracks 15 and 16 provide for the exchange of control signals and output signals measured by the transducers 13, under the control of and for processing by a signal processing arrangement 18. The conductive tracks 15, 16 may be arranged as signal busses, for example, comprising a plurality of conductive signal transmission lines. The conductive tracks 17 are arranged for transferring electric power to the transducers 13 and may terminate in contact terminals (not shown) for applying electric power from an external power source, for example.

In the embodiment shown, the conductive tracks 15, 16 are arranged in the form of addressing lines for addressing a particular transducer 13 by its position in the array 12, for activating or actuating the respective transducer 13, for example. To this end, the conductive tracks 15, 16 may connect to the signal processing arrangement 18 or separate addressing circuits may be provided (not shown) and controlled by the signal processing arrangement 18.

It will be appreciated that for addressing purposes, the transducers 13 may each comprise a unique identifier, ID, that can be addressed by the signal processing arrangement 18, for example. However, when performing a test or inspections, the processing arrangement 18 may also activate or actuate the transducers and process the output signals provided thereby by actuating the transducers in a known, predetermined order, for example.

The signal processing arrangement 18 may comprise digital data processing equipment, such as a digital data processor, micro-processor or microcomputer having on board storage for storing a control algorithm for operating the transducers 13 in the array 12. This, either in a stand alone modus or in an on-line modus wherein the signal processing arrangement 18 connects to a remote server in a data network, for example. To this end, the signal processing means may comprise communication circuits, for wireless or wired data transfer. However, separate communication means may likewise be provided. For the purpose of the present disclosure suitable, flexible electronic circuitry is known and available in practice.

The transducer arrangement 10, in its assembled form, may comprise a thickness of a few millimetres to a few centimetres, dependent on the height of the transducers 13 used, and may have dimensions of up to several meters, for example. Commercially available EMATs may scan or inspect a surface of about 1 cm by 1 cm, for example. In practice, transducer arrangements in the form of transducer modules having a length and width of say 0.5-1 meters, comprising about 2500 - 10,000 transducers, for example, can be relatively easily handled and applied at a surface to be inspected. Interface modules and terminals may be provided, for interconnecting adjacently arranged transducer arrangements 10. Using transducer modules has the advantage that, for example, in the case of malfunctioning of a transducer module, this module can be repaired or replaced, while the other modules may be kept in operation.

Figure 2 shows another embodiment of a transducer arrangement 20 in accordance with the present disclosure. In the embodiment shown, the electric contact layering 14 is comprised of a first flexible layer 21 of an electrically insulating material comprising the electrically conductive tracks 15, 16 for exchanging the control and measuring signals with the transducers 13, and a second flexible layer 22 of an electrically insulating material comprising the electrically conductive tracks 17 for transferring electric power to the transducers 13. Although not explicitly shown, control and signal tracks or lines 15 may be applied at one surface of the first layer 21 and control and signal tracks or lines 17 may be applied at the other surface of the first layer, to circumvent crossing lines or tracks. The respective tracks may comprise contact patches at the surface of the first layer opposite the transducers 13, for contacting purposes.

The conductive tracks or lines 17 may likewise be applied at both surfaces of the second layer 22. With this embodiment, the conductive tracks 17 may be designed with a low electrical resistance, to minimize energy loss. The conductive tracks 17 may also act a shield against externally radiating electromagnetic radiation produced by the transducers 13 when in operation and/or to shield the transducers 13 for external radiation influences. In the embodiment shown at the outwardly facing side of the second layer, an electrically conductive layer 23 is provided, acting as a mass contact for the electric power supply and as a shield against outwardly directed electromagnetic radiation produced by the EMATs when in operation.

The transducers 13 of a transducer arrangement 10, 20 and the processing arrangement 18 may be directly mounted at the flexible contact layering 14, 21, for example by soldering or by gluing or the like.

Figure 3 shows a transducer arrangement 30 in accordance with a further embodiment of the present disclosure, wherein the transducers 13 are integrated in a flexible substrate layer 31, schematically indicated by dashed lines. As schematically illustrated, the substrate layer 31 comprises a plurality of electric surface contact patches 32 connecting to terminals of the transducers 13, for electrically surface contacting of a respective conductive track 15, 16, 17 of the contact layering 14 when assembled to the substrate layers 31. It will be appreciated that the contact layering 14 may comprise a single layer or multiple layers as shown in the embodiment of Figures 1 and 2, respectively, and may be soldered or glued at the substrate layer 31.

In an embodiment of the transducer arrangement 40 shown in Figure 4, a mechanically flexible electric power generation layer 41 is provided and arranged at the electric contact layering 14. The electric power generation layer 41 is comprised of a plurality of electric power generator modules 42, arranged for generating and transferring electric power to the transducers 13 and the signal processing arrangement 18 via the electric contact layering 14.

The electric power generator modules may comprise thermo-electric power generator modules, such as the well known Peltier-elements, that may operate to convert heat of a surface to be inspected or monitored into electric power for operating the transducers 13 and processing equipment 18. In another embodiment, the electric power generator modules 42 may comprise photovoltaic or solar cells, in particular so-called flexible thin-film photovoltaic modules or cells, for converting solar energy into electric power for operating the transducers 13 and processing equipment

18.

It will be appreciated that a mix of thermo-electric and photovoltaic power generator modules may be used, whereas the modules 42 may be parallel and/or series connected, in order to achieve a particular supply voltage and supply current for powering of the transducer arrangement. It will be appreciated that the electric power generation layer 41 may also be applied in conjunction with the transducer arrangements 10, 20 and 30 shown in Figures 1, 2 and 3 respectively.

The modules 42, for maintaining flexibility of the transducer arrangement, are either constructed from mechanically flexible material, or in case of rather rigid modules 42, the dimensions and mutual spacing thereof are selected such that the transducer arrangement as a whole allows for bending and curvature thereof.

Although not explicitly shown, it will be appreciated that, besides transducers or sensors 13 of the EMAT type, the transducer arrangement 12, 30 may comprise other known types of transducers for metal surface inspection, such as radiographic transducers, electromagnetic transducers, acoustic transducers, and mechanical transducer. The transducer arrangement may comprise a mix of different transducer types.

For preventing moisture and other substances from affecting a surface to be inspected, one or both the electric contact layering 14, 21, 22 and the substrate layer 13 is a moisture proof flexible epoxy layer.

Electromagnetic acoustic transducers, EMATs, for conducting certified inspections or examinations of metallic surfaces, such as storage tank walls, are known in the prior art.

The construction of a single prior art EMAT is schematically illustrated in Figure 5. The basis of the EMAT 50 is formed by a magnetic component part, such as a permanent magnet 51, having north, N, and south, S, magnetic poles and an inductive coil component part 52 positioned opposite the magnet 51. Glass or epoxy spacers 53 are provided for supporting the magnet 51 and keeping same aligned with the coil 52. In use, the coil 52 is positioned electrically isolated from and opposite the surface to be inspected. For avoiding electromagnetic radiation in a direction other than the surface to be inspected, and providing a closed magnetic field, magnetic shunts 54 are provided for shunting the magnetic field lines of the permanent magnet 51.

In operation, an AC current in the electric coil 52 generates an eddy current in the surface of an object to be inspected which interacts with the external magnetic field of the magnet 51 and thereby produces so-called Lorenz forces along the surface. The Lorenz force generates ultrasound or ultrasonic waves in a direction perpendicular to the metallic surface of the object, due to the so-called electromagnetostrictive effect. A deterioration of the material of the surface to be inspected affects the Lorentz force and the propagation and reflection of the ultrasound waves affecting the magnetic field acting at the coil 52 and an electric signal thereby induced in the coil 52, which can be detected and output as a measuring signal of the transducer.

With EMAT 50 shown, surface areas under the area covered by the coil 52 can be inspected for thickness of the surface and material deteriorations like microcracks or checking, caused by corrosion, fatigue or strain in the surface to be inspected, for example.

Figure 6 shows a transducer arrangement 60 of the present disclosure, operating in accordance with the EMAT principle described above with reference to Figure 5.

The transducer arrangement 60 comprises an inductive coil part formed by an array 67 of flat coils 68 of electrically conducting material, such as copper, etched or deposited at a flexible first substrate layer 66 of electrically insulating material. The array 67 of coils 68 occupies the complete area of the first substrate layer 66.

The magnetic component part of the EMATs is formed by a flexible second substrate layer 61 comprising an array 62 of permanent magnets 63 integrated in a flexible epoxy layer, for example, as indicated by dashed lines. The magnets 63 may be formed by magnetic flakes, for example, that are magnetically directed to form a magnetic field in a particular direction, such as indicated by the adjacent magnetic north, N, and south, S, pole parts 64. The second or magnet substrate layer 61 further comprises through metallized electric contact surface patches 65 extending at both sides of the layer 61, for electrically contacting the contact terminals of a respective coil 68.

In the assembled state, the first 66 and second 61 substrate layers are aligned and attached to each other, to form an array of EMATs in accordance with the present disclosure. Electric power and measuring and control signals are provided to the coils 68, i.e. the contact terminals thereof, via the electric contact layering 14 and the contact patches 65.

The permanent magnets 63 may comprise plural pole parts 64, for example, or in addition or alternatively may comprise electric magnets (not shown). The transducer arrangement 60 may be constructed with a low height, in the millimetre range.

In a further embodiment, the transducer arrangement may comprise a plurality of strain gauge devices, arranged for measuring strain on the surface to be inspected, wherein the electric contact layering 14 is arranged for electrically contacting the strain gauge devices to the signal processing arrangement 18. In the embodiment shown in Figure 7, the electric coils 68 may be advantageously arranged as strain gauge devices.

With the array 12, 30, 62 and 67 of closely, adjacently arranged EMAT type transducers in accordance with the present disclosure, by operating the transducers in conjunction, controlled by the processing arrangement 18, one or several of the transducers may be actuated to operate in a transmitting or sound generating mode, whereas a transducer or a plurality of transducer adjacent to a transmitting transducer is or are actuated in a receiving mode, i.e. producing a measuring signal. By alternately actuating transducers in a transmission/receiving mode, a very effective inspection or monitoring across the whole surface to be inspected is achieved. The term adjacent is not limited to directly neighbouring EMATs.

Figure 7 illustrates a typical application of the transducer arrangement according to the present disclosure with a storage tank 70. In the embodiment shown, for illustrative purposes, several embodiments of the transducer arrangement are fixed, such as glued, to the cylindrical metallic outer surface 71 of the storage tank 70. Such as transducer arrangements 40, comprising photovoltaic electric power generator modules, applied at a surface part of the tank that is illuminated by sunlight, and transducer arrangements 20 that are attached to part of the tank wall 71 hat is in the shadow of another storage tank (not shown). In the embodiment shown, the complete side wall or surface 71 of the tank 70 is covered by transducer arrangements. It will be appreciated that the transducers arrangements 20 or 40, provided with thermo-electric power generator modules, for example, may be advantageously arranged between the outer wall 71 of the storage tank 70 and outer thermal isolation material, applied at the storage tank 70 (not shown).

In practice, the storage tank 70 may be surrounded by a so-called bunding or bund wall 72, for receiving substance stored by the tank 70 in case of failure, such as leakage, for example. In the area 73 between the storage tank 70 and the bund wall 72 no cables or other objects may be located. Accordingly, it is particularly advantage to apply at least a number of transducer arrangements 40 that are able to generate their own electric supply power that may also be used to power other transducer arrangements applied at the storage tank 70, not comprising electric power generator modules.

For data communication purposes, in the embodiment shown, wireless data transceivers 78 are provided, each time servicing four transducer arrangements 20, 40, for example. Data are wirelessly exchanged 79 with access or base stations 77 arranged in the vicinity of the storage tank 70 and outside the bund area 73. The base stations 77 may service other storage tanks and connect to a data network 75, such as the internet or an intranet, for exchanging data with a remote server 76 or a plurality of servers. The server 76 is arranged for processing the data received and for logging and providing the result to an operator or the like, for example.

The wireless data connection 79 may operate in accordance with any data transfer technology, such as termed Wi-Fi, Li-Fi, or mobile communication technology like 3G, 4G or 5G, for example. Li-Fi communication has the advantageous of not producing radio interference with other equipment at a terminal side, for example.

The base stations 77 may also be advantageously applied for measuring skewness of the storage tank 70, for example, by triangular measurements or the like.

Although not explicitly shown, it will be appreciated that the transducer arrangement according to the present disclosure may be applied to piping and other objects having a curved or flat surfaces to be inspected, either positioned above or under the ground, or at positions that are not accessible to a human being, for example.

Instead of gluing a transducer arrangement to a metal object, by using transducers having a relatively strong magnetic component part, the transducer arrangement according to the present disclosure may be magnetically attached to or applied at a metallic, i.e. a ferro-magnetic surface to be inspected or monitored, using the magnetic field of the transducer arrangement itself.

Those skilled in the art will appreciate other variations to the disclosed embodiments but comprised by the appended claims from practicing the claimed invention and /or from a study of the description, drawings and claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. A single processor or other digital processing unit may fulfil the functions of several items recited in the claims and features recited in mutually different dependent claims may be combined. Reference signs in the claims are provided for illustrative purposes only.

Claims

CONCLUSIONS

An electrically controlled flexible transducer assembly (10; 20; 30; 40; 60) for remote non-destructive inspection of a metal surface, in particular a metal surface of a storage tank or pipe, which assembly comprises:

- a grouping (12) of electromagnetic-acoustic converters ("electromagnetic acoustic transducers"), EMATs, (13) wherein each transducer is arranged for non-destructive inspection of a part of the surface to be inspected,

- a flexible electrical contact layer structure (14) comprising a plurality of electrically conductive tracks (15, 16, 17) for transferring electrical energy to and exchanging control and measurement signals from a converter (13) of the grouping of converters (12) ), and

- a signal processing assembly (18) for controlling the converters (13) for automatically performing the non-destructive inspection and for processing measurement signals from the converters (13).

The transducer assembly (10; 20; 30; 40; 60) according to claim 1, wherein the electrical contact layer structure (14) is opposed to the array of electromagnetic-acoustic transducers (12) and extends within its periphery.

The transducer assembly according to claim 1 or 2, wherein the transducers (13) and the processing assembly are mounted on the flexible contact layer structure.

The transducer assembly (30) according to claim 1 or 2, comprising a flexible substrate layer (31) incorporating the transducers (13) and comprising the substrate layer (31) electrically contacting surfaces (32) electrically connected to the transducers, for electrical surface contacting of a respective conductive trace of the contact layer structure (14).

The transducer assembly (60) according to claim 4, wherein the transducers (13) comprise a magnetic component part and an opposite inductive winding component part, wherein the flexible substrate layer (31) is composed of a first flexible substrate layer (66) comprising the winding component part (68) and a second flexible substrate layer (61) disposed on the first substrate layer (66), comprising the magnetic component part (64) of a transducer (13).

The transducer assembly (10) according to any of the preceding claims, wherein the electrical contact layer structure (14) is composed of a single layer of a flexible electrically insulating material, with a first surface comprising electrically conductive tracks (15, 16) adapted to the converters (13) exchange the control and measurement signals and a second surface, opposite the first surface, comprising electrically conductive tracks (17) adapted to transfer the electrical energy to the converters (13).

The transducer assembly (20) according to any of claims 1-5, wherein the electrical contact layer structure (14) is composed of a first layer of a flexible electrically insulating material (21) comprising electrically conductive tracks (15, 16) adapted to the converters (13) exchanging the control and measurement signals and a second layer of a flexible electrically insulating material (22) comprising electrically conductive tracks (17) adapted to transfer the electric energy to the converters (13) and an electrically conductive protective layer (23).

The transducer assembly (10; 20; 30; 40; 60) according to any of the preceding claims, wherein at least one of the electrical contact layer structure (14, 21, 22) and substrate layer (31) is a moisture-resistant flexible epoxy layer.

The transducer assembly (40) according to any of the preceding claims, further comprising a flexible electrical power generation layer (41) disposed on the electrical contact layer structure (14) and comprising a plurality of thermoelectric energy generator modules adapted to generate and by means of transferring the electrical contact layer structure (14) to the converters (13) and the signal processing assembly (18) of electrical energy.

The transducer assembly (40) of any one of claims 1-8, further comprising a flexible electrical power generation layer (41) disposed on the electrical contact layer structure (14) and comprising a plurality of photovoltaic modules arranged for generating and by means of transferring the electrical contact layer structure (14) to the converters (13) and the signal processing assembly (18) of electrical energy.

The converter assembly (40) of claim 10, wherein the photovoltaic modules are thin film photovoltaic modules.

The transducer assembly (40) according to claim 9, 10 or 11, wherein the flexible electrical power generation layer (41) comprising the plurality of thermoelectric energy generator modules (42) is within the perimeter of the array (12) of electromagnetic-acoustic transducers ( 13).

The transducer assembly (10; 20; 30; 40; 60) according to any of the preceding claims, further comprising a plurality of strain gauge devices adapted to measure elongation on the surface to be inspected, wherein the electrical contact layer structure (14) is arranged for electrically contacting the strain gauge devices with the signal processing assembly (18).

The converter assembly (10; 20; 30; 40; 60) according to any of the preceding claims, wherein the signal processing assembly (18) comprises at least one digital data processor integrated with the converter assembly.

The transducer assembly (10; 20; 30; 40; 60) as claimed in any one of the preceding claims, wherein the signal processing assembly (18) comprises at least one data communication device adapted to communicate with at least one of wired and wireless data communication with remote data processing equipment exchanging measurement and control data.

The transducer assembly (10; 20; 30; 40; 60) according to any of the preceding claims, wherein the signal processing assembly (18) extends within the periphery of the array (12) of electromagnetic-acoustic transducers (13).

An object comprising an outer metal surface, which object further comprises at least one transducer assembly (10; 20; 30; 40; 60) according to any one of the preceding claims, arranged on the outer metal surface (71) of the metal object (70 ).

The object of claim 17, wherein the object is a storage tank (70), in particular a bulk storage tank for holding gas or liquids, wherein the at least one transducer assembly (10; 20; 30; 40; 60) is fixed on the outer metal surface (71) of the storage tank (70) is attached.

The storage tank (70) according to claim 18, wherein a plurality of transducer assemblies (20; 40) are attached contiguous to the entire outer metal surface (71) of the storage tank (70).

The storage tank (70) of claim 19, wherein a wireless transceiver (78) is adapted to wirelessly exchange data with a plurality of adjacent transducer assemblies (20; 40) with a base station remote from the storage tank (70). (77).