阅读说明：本技术 改进的用于测量凝结和/或腐蚀进展的装置和方法 (Improved apparatus and method for measuring the progress of coagulation and/or corrosion ) 是由 伊夫·玛丽-路易斯·加布里埃尔·德仕美特 于 2018-11-07 设计创作，主要内容包括：一种测量导管的凝结和/或腐蚀进展的装置,包括：绝缘体,其围绕导管延伸；第一导体和第二导体,其布置为使得绝缘体的至少一部分位于导管与第一导体和第二导体之间,使得第一导体形成电容器的第一极,第二导体形成电容器的第二极,并且它们之间的部分包括第一极与第二极之间的电容耦合；以及至少一个测量仪,其配置为确定代表电容耦合的值。(An apparatus for measuring the progress of coagulation and/or corrosion of a conduit, comprising: an insulator extending around the conduit; a first conductor and a second conductor arranged such that at least a portion of the insulator is located between the conduit and the first conductor and the second conductor such that the first conductor forms a first pole of a capacitor, the second conductor forms a second pole of the capacitor, and the portion between them comprises a capacitive coupling between the first pole and the second pole; and at least one meter configured to determine a value representative of the capacitive coupling.)

1. An apparatus for measuring the progress of coagulation and/or corrosion of a conduit (1), comprising:

an insulator (2) extending around the conduit;

a first conductor (3A) and a second conductor (3B) arranged such that at least a portion of the insulator is located between the conduit and the first and second conductors, such that the first conductor forms a first pole of a capacitor (4C), the second conductor forms a second pole of the capacitor, and the portion between them comprises a capacitive coupling between the first and second poles; and

at least one meter (6) configured to determine a value representative of the capacitive coupling.

2. The apparatus of claim 1, wherein the first conductor and the second conductor are each implemented as a conductive coating or cladding for the insulator.

3. The apparatus of any of the preceding claims, wherein the first conductor and the second conductor are each shaped as at least a portion of a conductive sleeve configured to receive at least a portion of the insulator.

4. The apparatus of any of the preceding claims, wherein the at least one meter is configured to determine a frequency value representative of the capacitive coupling.

5. The apparatus of any one of the preceding claims, wherein the at least one meter is configured to drive a variable frequency alternating voltage or current through the capacitive coupling and to measure amplitude and phase variations of the variable frequency alternating voltage or current.

6. The apparatus of any one of the preceding claims, wherein the at least one measuring instrument comprises at least one oscillator.

7. An apparatus for measuring degradation of a surface layer on a catheter (1), comprising:

an insulator (2) extending around the surface layer on the conduit;

a first conductor (3A) and a second conductor (3B) at a distance from the first conductor, the first and second conductors being arranged such that at least a portion of the insulator is located between the conduit and the first conductor and between the conduit and the second conductor; and

at least one meter (6) configured to determine a value representative of an impedance of a surface layer underlying the portion of the insulator.

8. Device according to the preceding claim, characterized in that said at least one measuring instrument comprises an electrochemical impedance spectroscopy instrument.

9. The apparatus of claim 7 or 8, wherein the at least one meter comprises a DC meter.

10. The apparatus of any one of claims 7 to 9, comprising a monitoring controller configured to analyze the degradation of the surface layer based on one or more values determined by the at least one meter.

11. The device according to any one of claims 7 to 10, wherein the surface layer is any one of the following: coating, capping, oxide layer.

12. The device according to any one of the preceding claims, wherein the first conductor (3A) and the second conductor (3B) are arranged at a distance from each other, seen in the longitudinal direction of the catheter, or wherein the first conductor and the second conductor only at their outer ends at least partially overlap, seen in the axial direction of the catheter, and an insulating material is present between the outer ends of the first conductor and the second conductor.

13. The device according to any one of the preceding claims, characterized in that a first measuring instrument of the at least one measuring instrument is fixed on or in the insulator or on an outer layer (3I) of the insulator.

14. The device according to any of the preceding claims, comprising a third conductor (3C), the third conductor (3C) being arranged such that at least another part of the insulator (2) is located between the catheter and the second conductor (3B) and between the conductor and the third conductor (3C), wherein the at least one meter is configured to perform measurements between the second and third conductors.

15. The device according to any of the preceding claims, wherein the first conductor extends over a first length as seen in the longitudinal direction, and wherein the surface area of the first conductor is at least 10%, preferably at least 25%, more preferably at least 50% of the surface area of the catheter along the first length.

16. The device according to any one of the preceding claims, characterized in that the at least one measuring instrument is integrated in the insulator.

17. The apparatus of any one of the preceding claims, wherein the at least one meter comprises at least one of the following power sources: a wired power source, an energy generating power source, and a battery power source.

18. The apparatus according to any of the preceding claims, wherein the at least one meter is configured to wirelessly transmit the determined value to a wireless receiver of a monitoring controller, preferably by a communication technology having low power and long distance (low power wide area network).

19. Device as claimed in any of the foregoing claims, characterized in that the first conductor and the second conductor are arranged at a distance from one another along the insulating body, viewed in the longitudinal direction of the catheter.

20. The apparatus of claim 1, optionally and any of claims 2 to 6 and 11 to 19, comprising a monitoring controller configured to analyze the progress of coagulation and/or corrosion of the conduit based on one or more values determined by the or each meter.

21. The device according to claim 10 or 20, comprising at least one temperature sensor configured to measure temperature, preferably at the location of the insulator, and/or at least one humidity sensor configured to measure humidity, wherein the monitoring controller is configured to take into account the measured temperature and/or the measured humidity during the analysis of the condensation and/or corrosion progress.

22. Device according to the preceding claim, characterized in that said temperature sensor comprises a plurality of power sources.

23. The device of any one of the preceding claims, wherein the conduit is electrically conductive.

24. Device according to the preceding claim, characterized in that the conduit is grounded or floating.

25. The device according to any one of the preceding claims, wherein the transition area between the first conductor and the second conductor comprises a moisture barrier, preferably butyl tape or rubber.

26. The device of any one of the preceding claims, wherein at least one of the first conductor and the second conductor is at least partially made of aluminum or of stainless steel.

27. The arrangement according to any of the preceding claims, characterized in that at least one of the first and second conductors comprises a plurality of interconnected electrically conductive layer elements (3A ', 3B').

28. Device according to the preceding claim, characterized in that said plurality of conductive layer elements are strip-shaped.

29. The apparatus of any one of the preceding claims, wherein the first conductor and the second conductor are embedded in the insulator.

30. An apparatus as claimed in any preceding claim, further comprising a connection means between a first meter of the at least one meter and the first and second conductors, the connection means extending from the first and second conductors through the insulator to the first meter.

31. The apparatus of the preceding claim, wherein the first conductor has a first end and a second end, and wherein the apparatus further comprises: a first connector element extending from the first end through the insulator; and a second connector element extending from the second end through the insulator.

32. A monitoring controller for one or more devices according to any one of the preceding claims, the monitoring controller being configured to receive one or more values determined by the at least one meter and to analyze the coagulation and/or corrosion progress of the conduit based on the received one or more values, and/or to analyze the degradation of a surface layer on the conduit based on the received one or more values.

33. The monitoring controller of claim 32, comprising a wireless receiver configured to receive the one or more values determined by the at least one meter.

34. A method for measuring the progress of coagulation and/or corrosion of a conduit, comprising:

disposing an insulator around the conduit;

arranging a first conductor and a second conductor such that at least a portion of the insulator is between the conduit and the first conductor and the second conductor and such that the first conductor forms a first pole of a capacitor, the second conductor forms a second pole of the capacitor, and the portion therebetween includes a capacitive coupling between the first pole and the second pole; and

a value representative of the capacitive coupling is determined.

35. The method of claim 34, comprising providing each of the first and second conductors as a conductive coating or cladding for the insulator.

36. The method of any of claims 34 to 35, comprising providing each of the first and second conductors as at least a portion of a conductive sleeve configured to receive at least a portion of the insulator.

37. The method of any of claims 34 to 36, wherein determining the value comprises determining a frequency value representative of the capacitive coupling.

38. A method according to any one of claims 34 to 37, comprising determining a variable frequency alternating voltage or current by said capacitive coupling and measuring amplitude and phase variations of said variable frequency alternating voltage or current.

39. The method of any one of claims 34 to 38, comprising analyzing the catheter for coagulation and/or corrosion progression based on the determined one or more values.

40. A method for measuring degradation of a surface layer on a catheter (1), comprising:

-arranging an insulator (2) around the surface layer on the conduit;

arranging a first conductor (3A) and a second conductor (3B) at a distance from the first conductor such that at least a portion of the insulator is located between the conduit and the first conductor and between the conduit and the second conductor; and

determining a value representative of an impedance of a surface layer underlying the portion of the insulator.

41. The method of claim 40, wherein said determining is done using electrochemical impedance spectroscopy.

42. A method according to claim 40 or 41, wherein said determining comprises performing a DC measurement, for example using a potentiostat or a galvanostat.

43. The method of any one of claims 40 to 42, comprising analysing the deterioration of the surface layer based on the determined one or more determined values.

44. A method according to any one of claims 34 to 43, wherein said arranging a first conductor and a second conductor comprises arranging the first conductor and the second conductor at a distance from each other, seen in the longitudinal direction of the catheter, or so that the first catheter and the second catheter only partly overlap at their outer ends, seen in the longitudinal direction of the catheter.

45. A method according to any of claims 34 to 44, comprising wirelessly transmitting the determined value to a wireless receiver of the monitoring controller, preferably by a communication technique having low power and long range (low power wide area network).

46. A method according to any of claims 34 to 45, comprising arranging the first and second conductors at a spacing from one another along the insulator.

47. The method of any one of claims 34 to 46, comprising: measuring a temperature, preferably at the location of the insulator; and/or measuring humidity; and analyzing the condensation and/or corrosion progress while taking into account the measured temperature and/or the measured humidity.

48. The method of any one of claims 34 to 47, wherein the conduit is electrically conductive.

49. Method according to the preceding claim, comprising grounding the catheter or floating the catheter.

50. A method according to any one of claims 34 to 49, comprising arranging a moisture barrier strip, preferably butyl tape or rubber, in the transition region between the first and second conductors.

51. The method of any one of claims 34 to 50, comprising embedding the first and second conductors in the insulator.

52. The method according to any of the claims 34 to 51, wherein said arranging a first conductor comprises arranging a plurality of interconnected electrically conductive elongated elements (3A ', 3B') around said catheter.

53. The method of any one of claims 34 to 52, wherein determining a value comprises connecting a meter using a connection device extending from the first and second conductors through the insulator.

54. A method for analyzing coagulation and/or corrosion progression of a conduit and/or degradation of a surface layer on the conduit, comprising:

receiving one or more values determined according to the method of any one of claims 34 to 53; and

analyzing the coagulation and/or corrosion progression of the conduit and/or the degradation of the surface layer of the conduit based on the received one or more values.

55. The method of the preceding claim, comprising wirelessly receiving the determined one or more values.

56. An insulating element, preferably for use in an apparatus according to any of claims 1 to 31 or in a method according to any of claims 34 to 55, comprising:

an insulator sleeve configured to extend around the conduit and having an outer surface;

a conductor embedded in the insulator sleeve;

at least one connecting element extending from the conductor through the insulator sleeve to an outer surface of the insulator sleeve.

57. Insulating element according to the preceding claim, characterized in that the conductor is shaped as a conductor sleeve, the length of which is smaller than the length of the insulator sleeve, and the conductor sleeve is completely embedded in the insulator sleeve.

58. An insulating element according to claim 56, characterized in that the conductor comprises a plurality of interconnected conductive layer elements (3A ', 3B').

59. The insulating element of any one of claims 56 to 58, wherein the insulator sleeve comprises a first insulator layer and a second insulator layer, and wherein the conductor is disposed between the first insulator layer and the second insulator layer.

60. The insulating element of any one of claims 56 to 59, further comprising a gauge disposed on or in the insulator sleeve.

61. Insulating element according to the preceding claim, characterized in that the measuring instrument is configured to transmit the measured values wirelessly to a wireless receiver of a monitoring controller.

Technical Field

The present invention relates to a device and a method for measuring the progress of coagulation and/or corrosion of a conduit. Furthermore, the invention relates to a monitoring controller for one or more such devices.

Background

For transporting certain fluids, it is important that these fluids suffer as little heat loss as possible. Therefore, conduits for transporting such fluids below the dew point temperature are typically insulated. This is achieved, for example, by enclosing the pipe with an insulating shell, which is optionally provided with a vapour barrier (vapour barrier).

However, there is a risk of condensation in such a device (entrainment). Since the device is typically exposed to ambient air, and if there is a leak in the enclosed vapor barrier, moisture in the ambient air can condense onto the conduit at the surface in contact with the inside of the insulator. The term Corrosion Under Insulation (CUI) is commonly used to describe this situation. Over time, such condensed moisture can cause corrosion of the conduit, thereby damaging the conduit (metal corrosion, conduit eventually losing its flow efficiency, effectiveness, strength, and water tightness). Removal of such condensed moisture is difficult and replacement of the complete equipment is very expensive. It is therefore desirable to detect condensation as early as possible before or in any case before the actual corrosion occurs, so that the insulation can be replaced in part less expensively.

Known systems for measuring coagulation and the progression of corrosion due to coagulation on a conduit utilize a thermal camera to detect the location of thermal pattern deviations. However, this solution is not effective because it is expensive and cumbersome and does not allow, for example, to detect heat and/or cold losses in the blind spot. Furthermore, it is difficult to interpret such thermal detection: it is not clear whether heat or cold loss can be attributed to locally thinner insulator or vapor barrier leaks and can change due to heat reflection on bright surfaces.

Other known measurement systems include time domain reflectometry techniques that determine characteristics of an electrical line by observing a reflected waveform. A disadvantage of this technique is that the location of condensation and/or leakage cannot be accurately detected, particularly when condensation and/or leakage occurs at different locations along the line. These systems still require the user to search for leaks and condensation on the catheter with a thermal camera.

To address these problems, a device for electrically conductive conduits is provided in belgium patent application BE2014/0429 (now entitled belgium patent BE1022693B9) in the name of the same applicant as the present patent application, wherein an insulator extends around the conduit, and wherein at least one electrical conductor is arranged over, on or in the insulator such that at least a portion of the insulator is located between the conduit and the or each conductor and such that the conduit forms a first pole of a capacitor, the or each conductor forming a second pole of the capacitor, and the portion therebetween forming a portion of a dielectric, and wherein at least one meter is configured to determine a value for the or each conductor representative of the capacitive action of the corresponding capacitor.

However, in such devices, there is a problem that the catheter must be electrically conductive. Therefore, such devices cannot be used for example for plastic catheters without doubt. Furthermore, in such devices, there is a risk of an electrical short circuit occurring between the catheter and the at least one electrical conductor (for example at the location of the catheter valve or other protrusion), so that the capacitive effect is impeded and, therefore, it is no longer worthwhile to make measurements.

Disclosure of Invention

The present invention aims to solve these problems.

To this end, the invention provides a device for measuring the progress of coagulation and/or corrosion of a conduit, comprising: an insulator extending around the conduit; and first and second conductors arranged such that at least a portion of the insulator is located between the conduit and the first and second conductors, such that the first conductor forms a first pole of the capacitor, the second conductor forms a second pole of the capacitor, and the portion therebetween includes the capacitive coupling between the first pole and the second pole. The apparatus also includes at least one meter configured to determine a value representative of the capacitive coupling.

This solution allows measuring the condensation and/or corrosion progress with various ways of conduits, which do not necessarily need to be electrically conductive, since not the conduits themselves act as second poles of the capacitor, but rather as conductors provided separately for this purpose. Furthermore, for the same reason, the risk of useless measurements due to an electrical short between the catheter and one of the two conductors can be reduced, since even if one of the two conductors makes accidental electrical contact with the catheter, the other of the two conductors continues to act as the counter-pole of the capacitor. The inventive nature of this solution is based in particular on the inventors' innovative insights: the capacitive effect between the first conductor and the second conductor can be measured more accurately than in the known device between the position of the conductor and the position of the catheter. Tests have shown that in the event of a leak, the determined value (in this case the capacitance itself) can vary by a factor of the order of about 100 or 1000, while in the event of fluctuations in temperature and humidity in the surrounding area only small changes (of the order of a few percent) occur, which allow the condensation and/or the progress of corrosion to be measured.

A further advantage of embodiments of the device is that the first and second conductors and the meter can be arranged on an already installed insulator, still without having to make electrical connections between the meter and the conduit.

According to an embodiment, the first conductor and the second conductor are arranged at a distance from each other, or the first conductor and the second conductor only partially overlap at their outer ends, as seen in the longitudinal direction of the catheter. In this way, the capacitive coupling may extend along a substantial length of the insulator to allow any condensation or leakage to be detected along that length.

A first meter of the at least one meter may be arranged between the first conductor and the second conductor, typically fixed, on an insulator or on an outer layer on an insulator. For example, an outer layer may be disposed on the insulator between the first inductor and the second inductor, and the first meter may be secured to the outer layer. The outer layer may be a conductive outer layer, and the conductive outer layer may be grounded or floating.

According to an embodiment, the device comprises a third conductor arranged such that at least a further portion of the insulator is located between the conduit and the second conductor and the third conductor, such that the second conductor forms a first pole of the further capacitor, the third conductor forms a second pole of the further capacitor, and the further portion between them comprises a further capacitive coupling between the first pole and the second pole. Wherein the at least one meter is configured to determine a value representative of the further capacitive coupling. In this way, a larger portion of the insulation may be monitored with at least one meter.

According to an embodiment, the second conductor and the third conductor are arranged at a distance from each other, or at least partially overlap only at their outer ends, as seen in the longitudinal direction of the catheter.

According to an embodiment, the first conductor extends over a first length as seen in the longitudinal direction of the catheter, and the surface area of the first conductor is at least 10%, preferably at least 25%, more preferably at least 50% of the surface area of the catheter along this first length. The surface area may also be equal to the surface area of the catheter along the first length, or even greater than the surface area of the catheter along the first length. By increasing the surface area of the first conductor and the second conductor, the capacitive coupling between the first conductor and the second conductor is increased. Therefore, the accuracy of the measurement will increase.

According to an embodiment, the first conductor and the second conductor are each realized as a conductive coating or cladding for the insulator. In this way, the device can be installed more simply as a whole (with or without at least one measuring instrument).

According to an embodiment, the first conductor and the second conductor are each shaped as at least a portion of a conductive sleeve configured to receive at least a portion of an insulator. In this way, the respective poles of the capacitor can cover a large surface area and thus have a large capacitance.

According to an embodiment, at least one meter may be configured to determine a frequency value representative of the capacitive coupling. In this way, a value representative of the capacitive coupling can be determined with a simple determinable parameter.

According to an embodiment, at least one meter may be configured to drive a variable frequency alternating voltage or current by capacitive coupling and to measure amplitude and phase variations of the variable frequency alternating voltage or current. In this way, simple determinable parameters (amplitude and phase or real or imaginary part of the alternating voltage or current) can be utilized for the purpose of determining the impedance value representing the connection. The impedance is frequency dependent and indicates the progress of coagulation and corrosion.

According to an embodiment, the at least one measuring instrument may comprise at least one oscillator.

According to an embodiment, the at least one meter may be integrated in the insulator. In this way, the at least one measuring device is better protected from external influences.

According to an embodiment, the at least one meter may comprise at least one of the following power supplies: a wired power source, an energy generating power source, and a battery power source. Wired power can achieve very long measured lifetimes, while battery power can be inexpensive and easy to install. The energy generating power source can be very energy efficient and autonomous, which is advantageous in case of hard to reach conduits, such as long distance conduits.

According to an embodiment, the at least one meter may be configured to wirelessly transmit the determined value to a wireless receiver of the monitoring controller, preferably by a communication technology having low power and long distance (low power wide area network). In this way, convenience of use can be increased. Furthermore, centralized control may be possible.

According to an embodiment, the first conductor and the second conductor may be arranged at a distance from each other along the insulator. In this way, a greater range of the catheter can be covered and the accuracy of the measurement can be increased.

According to an embodiment, the apparatus may comprise a monitoring controller configured to analyse the progress of coagulation and/or corrosion of the conduit based on one or more values determined by the or each meter.

According to an embodiment, the apparatus may comprise: at least one temperature sensor configured to measure a temperature, preferably at a location of the insulator; and/or at least one humidity sensor configured to measure humidity, wherein the monitoring controller is configured to take into account the measured temperature and/or the measured humidity during the analysis of the condensation and/or corrosion progress. The temperature sensor and/or the humidity sensor allow the analysis to be performed with greater accuracy.

According to an embodiment, the conduit may be electrically conductive and the at least one meter may be configured to consider, during the determination of the value, a capacitive contribution of a first additional capacitor having a pole formed by the first conductor and the conduit and a capacitive contribution of a second additional capacitor having a pole formed by the second conductor and the conduit.

In this way, the device according to the invention can be used effectively not only for non-conductive catheters, but equally for conductive catheters. In the latter case, since the guide tube then forms an electrical contact between, on the one hand, the first additional capacitor formed by the first conductor and the guide tube and, on the other hand, the second additional capacitor formed by the guide tube and the second capacitor, wherein the insulator in each case serves as a respective dielectric, the capacitive coupling can advantageously be measured up to a deeper position of the insulator (i.e. closer to the guide tube). Such a measurement may be more effective when the insulation is gas tight, since the formed condensation can then diffuse at the location of the conduit.

According to an embodiment, the conduit may be grounded. Alternatively, the catheter may be a floating catheter.

According to an embodiment, the transition region between the first conductor and the second conductor may comprise a moisture barrier strip. The moisture barrier strip is preferably butyl tape or rubber. In this way, the insulator can be better protected from moisture penetrating from the outside.

According to an embodiment, at least one of the first conductor and the second conductor may be at least partially made of aluminum or of stainless steel. In this way, the device may be more weather resistant.

According to an embodiment, at least one of the first conductor and the second conductor comprises a plurality of interconnected electrically conductive layer elements. For example, the electrically conductive layer elements may be elongated elements, extending along a longitudinal direction of the catheter and arranged at a distance from each other around the catheter, seen in a cross-section perpendicular to the longitudinal direction. In this way, a sufficiently large surface area of the conductor is achieved, making the installation of the device easier, while reducing material costs and making the device lighter. In this way, the surface area of the conductor is sufficiently greater than the thickness, thereby increasing the capacitive coupling between the first conductor and the second conductor. For example, the plurality of electrically conductive elongated elements may be strip-shaped. In other exemplary embodiments, the conductive layers may be cylindrical elements arranged at a distance from each other, seen in the longitudinal direction.

In an exemplary embodiment, the interconnected plurality of conductive layer elements is interposed between a first insulating layer and a second insulating layer, wherein the first insulating layer and the second insulating layer together form an insulator. By using a plurality of interconnected conductive layer elements instead of a complete sleeve, the adhesion between the first and second insulating layers may be improved.

According to an embodiment, the first conductor and the second conductor are embedded in an insulator. For example, the insulator may include a first insulator layer extending around the conduit and a second insulator layer extending around the first insulator, and wherein the first conductor and the second conductor are at least partially embedded in the second insulator layer. In this way, the first conductor and the second conductor can be easily integrated in the insulator and protected from external influences from the environment.

According to an embodiment, the apparatus may further comprise a connection device between the meter and the first and second conductors, the connection device extending from the first and second conductors through the insulator to the meter. In this way, the meter is easily connected to the conductor, thereby reducing the time required to install the meter.

According to an embodiment, the first conductor has a first end and a second end, and the apparatus further comprises: a first connector element extending from the first end through the insulator; and a second connector element extending from the second end through the insulator.

The present invention also provides a monitoring controller for use with one or more of the devices described above, the monitoring controller configured to receive one or more values determined by at least one meter and to analyze the progress of coagulation and/or corrosion of the conduit based on the received one or more values.

Those skilled in the art will appreciate that advantages and objects similar to those of the apparatus apply mutatis mutandis to the corresponding monitoring controller.

According to an embodiment, the monitoring controller may comprise a wireless receiver configured to receive the one or more values determined by the at least one meter.

The invention also includes a method for measuring the progress of coagulation and/or corrosion of a conduit. The method comprises the following steps: an insulator is disposed around the conduit. The method also includes arranging the first conductor and the second conductor such that at least a portion of the insulator is between the conduit and the first conductor and the second conductor such that the first conductor forms a first pole of the capacitor, the second conductor forms a second pole of the capacitor, and the portion therebetween includes a capacitive coupling between the first pole and the second pole. The method also includes determining a value representative of the capacitive coupling.

It will be appreciated by a person skilled in the art that advantages and objects similar to those of the device apply mutatis mutandis to the corresponding method.

According to a preferred embodiment, the first conductor and the second conductor are arranged at a distance from each other, seen in the longitudinal direction of the catheter, or are arranged such that the first catheter and the second catheter only partly overlap at their outer ends.

According to a preferred embodiment, the third conductor is arranged such that at least a further portion of the insulator is located between the conduit and the second and third conductors, and such that the second conductor forms a first pole of the further capacitor, the third conductor forms a second pole of the further capacitor, and the further portion of the insulator comprises a further capacitive coupling between the first pole and the second pole. A value representative of the other capacitive coupling is determined. Preferably, the second conductor and the third conductor are arranged at a distance from each other, viewed in the longitudinal direction of the catheter, or are arranged such that the second conductor and the third conductor only partially overlap at their outer ends.

According to a preferred embodiment, each conductor is arranged along the first length with a surface area of at least 10%, preferably at least 25%, more preferably at least 50% of the surface area of the conduit along the first length. The surface area may also be more or less equal to the surface area of the catheter along the first length, or even larger than the surface area of the catheter along the first length.

The length of the conductor may be, for example, between 0.5m and 10m, depending on the type of conduit to be insulated. The diameter of the insulator may for example be between 5mm and 1200mm, preferably between 10mm and 500 mm. The distance between the first conductor and the second conductor may be, for example, between 1cm and 200cm, preferably between 2cm and 150 cm.

According to a preferred embodiment, the method comprises providing each of the first conductor and the second conductor as a conductive coating or cladding for the insulator.

According to a preferred embodiment, the method includes providing each of the first conductor and the second conductor as at least a portion of a conductive sleeve configured to receive at least a portion of an insulator.

According to a preferred embodiment, the method of determining a value comprises determining a frequency value representing the capacitive coupling.

According to a preferred embodiment, the method comprises driving the variable frequency alternating voltage or current by capacitive coupling and measuring amplitude and phase variations of the variable frequency alternating voltage or current.

According to a preferred embodiment, the method comprises integrating at least one meter in the insulator.

According to a preferred embodiment, the method comprises wirelessly transmitting the determined values to a wireless receiver of the monitoring controller, preferably by a communication technology having low power and long distance (low power wide area network).

According to a preferred embodiment, the method comprises arranging the first conductor and the second conductor at a distance from each other along the insulator.

According to a preferred embodiment, the method comprises analyzing the coagulation and/or corrosion progression of the conduit based on the one or more values determined.

According to a preferred embodiment, the method comprises: measuring the temperature, preferably at the location of the insulator; and/or measuring humidity; and analyzing the progress of condensation and/or corrosion while taking into account the measured temperature and/or the measured humidity.

According to a preferred embodiment, the conduit is electrically conductive and the determination of the value comprises taking into account the capacitive contribution of a first additional capacitor having a pole formed by the first conductor and the conduit and the capacitive contribution of a second additional capacitor having a pole formed by the second conductor and the conduit.

According to a preferred embodiment, the method comprises grounding the conduit. Alternatively, the method comprises floating the catheter.

According to a preferred embodiment, the method comprises arranging a moisture barrier strip, preferably butyl tape or rubber, in the transition area between the first conductor and the second conductor.

According to an exemplary embodiment, the method includes embedding the first conductor and the second conductor in an insulator. For example, a first insulator layer may be disposed about the conduit and a second insulator layer may be disposed about the first insulator layer, wherein the first conductor and the second conductor may be at least partially embedded in the second insulator layer or may be interposed between the first insulator layer and the second insulator layer.

According to an exemplary embodiment, arranging the first conductor and/or the second conductor comprises arranging the interconnected plurality of electrically conductive elongated elements around the catheter, e.g. the interconnected plurality of electrically conductive elongated elements extend along a longitudinal direction of the catheter and are arranged at a distance from each other around the catheter as seen in a cross-section perpendicular to the longitudinal direction.

According to an exemplary embodiment, the determining of the value comprises connecting the meter using a connection device extending from the first conductor and the second conductor through the insulator to the meter. For example, the method may include disposing a first connector element to the first conductor through the insulator and disposing a second connector element to the second conductor through the insulator.

The present invention also provides a method for analysing the progress of coagulation and/or corrosion of a conduit, comprising receiving one or more values determined according to the method described above; and analyzing the progress of coagulation and/or corrosion of the conduit based on the received one or more values.

According to an embodiment, the method includes wirelessly receiving the determined one or more values.

According to another aspect of the present invention, there is provided an apparatus for measuring degradation of a surface layer on a catheter, comprising: an insulator extending around a surface layer on the conduit; a first conductor and a second conductor at a distance from the first conductor, the first conductor and the second conductor being arranged such that at least a portion of the insulator is located between the conduit and the first conductor and between the conduit and the second conductor; and at least one meter configured to determine a value representative of an impedance of a surface layer underlying the portion of the insulator.

According to prior art solutions, the degradation of the surface layer is typically measured directly on the surface layer using electrochemical impedance spectroscopy measurements. In the case of an isolated pipe that cannot be directly accessed to the surface layer, measurements may be performed between the pipe and the conductor surrounding the insulation. However, it has been found that such measurements do not provide accurate results due to external noise. By using a first conductor and a second conductor as described above, any external noise will be present on both the first conductor and the second conductor and will be cancelled out as the measurement is a differential measurement performed between the first conductor and the second conductor

The at least one meter may comprise an AC impedance meter, for example, an electrochemical impedance spectroscopy meter. Using such measurements, the phase and amplitude of the impedance are obtained as a function of frequency. When the surface layer deteriorates, the impedance of the surface layer changes, which results in a change in the phase measurement and a change in the amplitude measurement.

Additionally or alternatively, the at least one meter may comprise a DC impedance meter, such as a potentiostat or a galvanostat. For example, potentiostat measurements will work when the insulator has been wet, so that ion transport can occur through the insulator and through the surface layer, resulting in a measurement representative of the impedance of the surface layer. Other gauges are also possible as long as they can determine a value representing the deterioration of the surface layer under the portion of the insulator. The apparatus may also include a monitoring controller configured to analyze the degradation of the surface layer based on one or more values determined by the at least one meter.

The surface layer may for example be any of the following: coating, capping, oxide layer. For example, the surface layer may be a corrosion-resistant layer, a protective layer, or the like.

The surface layer may be a layer that adheres to the catheter or may be a layer that does not adhere to the catheter, such as a separate foil.

The thickness of the surface layer is typically less than the wall thickness of the catheter. For example, the thickness of the surface layer may be less than 10mm, preferably less than 9mm, more preferably less than 8 mm.

According to another aspect of the present invention, there is provided a method for measuring degradation of a surface layer on a catheter, comprising: disposing an insulator around a surface layer on the conduit; arranging a first conductor and a second conductor at a distance from the first conductor such that at least a portion of the insulator is between the conduit and the first conductor and between the conduit and the second conductor; and determining a value representative of the impedance of the surface layer underlying the portion of the insulator. The method may further include analyzing the degradation of the surface layer based on the determined one or more values.

This determination may be done using AC impedance measurements (such as electrochemical impedance spectroscopy) or DC measurements (such as measurements with a potentiostat or galvanostat).

Preferred and exemplary features of the above disclosed apparatus and method for measuring the progress of coagulation and/or corrosion of a conduit may also be present in the apparatus and method for measuring the degradation of a surface layer on a conduit. Furthermore, the arrangement/method may be combined, i.e. the same arrangement may be provided with a first meter to determine a value representing the capacitive coupling and a second meter to determine a value representing the impedance of the surface layer below the portion of the insulation. In fact, the same insulator and first and second conductors may be used to perform both measurements. When the apparatus/method is combined, a first meter configured to determine a value representative of the capacitive coupling may periodically perform measurements at a first frequency. A second meter configured to determine a value representative of the impedance of the surface layer will typically require a more complex measurement and take longer to perform than the duration of the first measurement of the value representative of the capacitive coupling. In a possible embodiment, the measurement of the value representative of the impedance of the surface layer by the second measuring instrument may be performed periodically, but is typically performed at a second frequency lower than the first frequency, or aperiodically, for example only when the first measurement by the first measuring instrument indicates a leak, water ingress or condensation.

According to another aspect of the present invention there is provided an insulating element, preferably for use in an apparatus or method according to any of the above embodiments, comprising: an insulator sleeve configured to extend around the conduit and having an outer surface; a conductor embedded in the insulator sleeve; at least one connecting element extending from the conductor through the insulator sleeve to an outer surface of the insulator sleeve. Such insulating elements may be arranged around the catheter, adjacent to each other, seen in the longitudinal direction of the catheter. The connection element allows to connect the conductor to a meter or to another conductor of an adjacent insulating element.

According to an exemplary embodiment, the conductor is shaped as a conductor sleeve, the length of which is smaller than the length of the insulator sleeve, and the conductor sleeve is completely embedded in the insulator sleeve. According to another embodiment, the conductor comprises a plurality of interconnected conducting layer elements, e.g. elongated elements, extending in a longitudinal direction of the insulator sleeve and arranged at a distance from each other around the insulator sleeve as seen in a cross-section perpendicular to the longitudinal direction.

According to an exemplary embodiment, the insulator sleeve comprises a first insulator layer and a second insulator layer. The conductor may be disposed between the first insulator layer and the second insulator layer, or may be embedded in the second insulator layer.

According to an exemplary embodiment, the insulating element further comprises a gauge arranged on or in the insulator sleeve. The meter may be configured to wirelessly transmit the measured values to a wireless receiver of the monitoring controller, preferably by a communication technique having low power and long range (low power wide area network).

According to an exemplary embodiment, the surface area of the conductor is more than 10%, preferably more than 25%, more preferably more than 50% of the surface area of the outer surface of the insulator sleeve.

According to an exemplary embodiment, the conductor is formed as a conductive coating or cladding.

According to an exemplary embodiment, the insulating member includes: at least one temperature sensor configured to measure a temperature; and/or at least one humidity sensor configured to measure humidity.

According to an exemplary embodiment, the conductor is at least partially made of aluminum or of steel (e.g., stainless steel or galvanized steel).

According to an exemplary embodiment of the insulating element, the at least one connector element comprises: a first connector element arranged at a first end of the conductor, seen in the longitudinal direction of the insulator sleeve; and a second connector element arranged at the other end of the conductor.

The length of the conductor may be, for example, between 0.5m and 10m, depending on the type of conduit to be insulated. The diameter of the insulator may for example be between 5mm and 1200mm, preferably between 10mm and 500 mm.

The invention also relates to an assembly of insulating elements as described above. When the insulating elements are arranged around the catheter, the conductor of a first insulating element may be electrically connected to the conductor of one or two adjacent insulating elements. The conductor is also connected to a meter. This allows the device as described above to be formed in a convenient manner.

It will be appreciated by a person skilled in the art that advantages and objects similar to those of the device apply mutatis mutandis to the insulating element and the assembly of insulating elements.

Drawings

The invention will now be further described with reference to exemplary embodiments shown in the drawings. These exemplary embodiments are intended to provide a better understanding of the above-described features, advantages, and objects of the present invention. They do not limit the invention in any way.

In the drawings:

fig. 1A is a schematic illustration of an embodiment of the device according to the invention in a longitudinal cross-section along the longitudinal direction of the non-conductive conduit;

fig. 1B is a schematic illustration of another embodiment of the device according to the invention in a longitudinal cross-section along the longitudinal direction of the electrically conductive catheter;

figure 1C is a schematic illustration of a portion of a first alternative embodiment of a device according to the present invention;

figure 1D is a schematic illustration of a part of a second alternative embodiment of the device according to the invention;

FIG. 2 is a schematic illustration of an embodiment of an electronic circuit for use in a meter according to the present invention;

FIG. 3 is a schematic illustration of an alternative embodiment of an electronic circuit for use in a meter according to the present invention;

FIG. 4 is a schematic illustration of another embodiment of an electronic circuit for use in a meter, according to the present invention;

fig. 5 is a schematic illustration of an embodiment of the device in a longitudinal cross-section along the longitudinal direction of the catheter;

FIG. 6 is a schematic diagram indicating capacitive coupling for the embodiment of FIG. 5;

FIG. 7 is a schematic perspective view of an alternative embodiment of a device;

8A-8D schematically illustrate alternative embodiments of the apparatus showing different ways of connecting the meter;

FIG. 9 is a schematic longitudinal cross-section of an embodiment of an assembly of insulating elements; and

FIG. 10 is a schematic longitudinal cross-section of an embodiment of an insulating element;

FIG. 11 schematically shows an embodiment of an apparatus for determining degradation of a surface layer on a catheter; and

fig. 12A and 12B show the measured amplitude and phase as a function of frequency for a device with a complete surface layer and a catheter with a degraded surface layer, respectively.

In the drawings, the same or similar elements are denoted by the same reference numerals.

Detailed Description

Fig. 1 shows a schematic illustration of an embodiment of the device according to the invention in a longitudinal cross-section along the longitudinal direction of the non-conductive conduit. The figure shows the catheter 1 in a cross section along the longitudinal axis of the catheter 1, but it will be appreciated by the skilled person that other embodiments of the invention may also be applied in catheters of different shapes.

The insulator 2 extends around the pipe 1. The insulator 2 may be configured for thermal insulation, but (alternatively or additionally) may also be configured for sound insulation. The insulator 2 may for example comprise a preformed shell clamped or fastened around the conduit 1, or may for example comprise a mat wrapped around the conduit 1. Embodiments of the present invention are applicable to all types and forms of insulators.

In the insulator 2, the first conductor 3A and the second conductor 3B are arranged such that at least a part of the insulator 2 is located between the conduit 1 and the first conductor 3A and the second conductor 3B, such that the first conductor 3A forms a first pole of the capacitor 4C, the second conductor 3B forms a second pole of the capacitor 4C, and said part between them comprises a capacitive coupling between the first pole and the second pole. In other words, the capacitor 4C has two poles (i.e., the first conductor 3A and the second conductor 3B), and a portion of the insulator 2 located between the two poles may serve as (a part of) a dielectric layer of the capacitor 4C. The entire capacitive coupling may then be referred to as C, for example_eq(not shown) as shown in fig. 2-4.

Fig. 1A also shows a meter 6, the meter 6 being configured to determine a value representative of the capacitive coupling. For this purpose, the measuring device 6 is connected to the first conductor 3A via a first connection 6A and to the second conductor 3B via a second connection 6B. Those skilled in the art will appreciate that the embodiment shown in the drawings schematically shows the measuring instrument 6 and that a wide variety of practical embodiments may be selected depending on the actual situation.

In some embodiments, the meter 6 may (preferably wirelessly) transmit the determined value to a (wireless receiver of) a monitoring controller (not shown) for use with one or more devices according to the invention. The monitoring controller may be configured to receive one or more values determined by the meter 6 and to analyze the coagulation and/or corrosion progress of the conduit 1 based on the received one or more values. If wireless communication is used, this may be done, for example, by a communication technology having low power and long range (low power wide area network). Examples of which are: LoRa/LoRaWAN, SigFox, Bluetooth (LE). Alternatively, communication technologies with relatively high power may also be used, such as wireless local area network technologies (wireless local area network, WLAN, such as Wi-Fi, i.e. IEEE802.11) or mobile cellular network technologies (such as GSM and related standards and protocols).

Fig. 1A also shows an optional strip 5, which strip 5 covers the area of the insulator 2 that is located in the transition area between the first conductor 3A and the second conductor 3B. In this context, the transition region may comprise a region or space between the edges and/or walls of the outer ends of the first and second conductors 3A, 3B. The strip 5 is advantageously moisture-proof to prevent moisture from penetrating from the outside. In a preferred embodiment, the strip 5 is optionally butyl tape or rubber. Advantageously, the strip 5 also covers a sufficiently wide portion (for example, at least 1cm, preferably at least 5cm) of the respective outer ends of the first and second conductors 3A, 3B, for better operation.

According to an alternative embodiment, the first conductor 3A and the second conductor 3B may be integrated in a coating or cladding of the insulator 2. This has the advantage that the device can be installed in its entirety, requiring fewer operating steps.

In a particular embodiment (as shown herein), the first conductor 3A and the second conductor 3B are each shaped as at least a portion of a conductive sleeve configured to receive at least a portion of the insulator 2. This has the advantage that each conductor can cover a larger surface area than in some other forms, such as a cord or an elongated plate, and thus the capacitance can also be larger.

In some embodiments, the meter 6 may be powered by a potential wire (not shown). This has the advantage that the measurement can be more accurate. In other embodiments, the meter 6 may be powered by a battery (not shown). This has the advantage that this is cheaper and easier to install. In a preferred embodiment, these two alternatives can be combined, for example, battery power can be used first for a short period of time and for a short period of time to fully detect the presence of the risk of condensation and/or corrosion progression, and then, after detection, continued to be supplied with wire for a longer period of time to make more accurate measurements.

Fig. 1B shows a schematic illustration of another embodiment of the device according to the invention in a longitudinal cross-section along the longitudinal direction of the electrically conductive catheter. The figure shows a first additional capacitor 4A and a second additional capacitor 4B. The figure shows a first additional capacitor 4A and a second additional capacitor 4B. These additional capacitors are optional in the sense that values determined based in part on them are useful when the catheter 1 is conductive (as shown in the figure), as is the case in the figure. This has the advantage that, since the conductive conduit 1 is capacitively active here, moisture and/or corrosion can be measured more accurately up to a deeper location in the insulation 2 (i.e. closer to the conduit 1).

In such other embodiments, the capacitive coupling may be regarded as a parallel circuit of the capacitor 4C on the one hand and as a series circuit of the first additional capacitor 4A and the second additional capacitor 4B on the other hand. The entire capacitive coupling may then be referred to as C, for example_eq(not shown) as shown in fig. 2-4.

Fig. 1C shows a schematic illustration of a part of a first alternative embodiment of the device according to the invention. The figure shows in particular a cross section of a part of the device in which the first conductor 3A and the second conductor 3B are close to each other. In this first alternative embodiment, the first conductor 3A and the second conductor 3B are arranged to at least partially overlap at their respective outer ends, wherein the electrically insulating strip 5 extends over an area of at least the same size as the overlap in a transition area between the first conductor 3A and the second conductor 3B to prevent direct electrical conduction between the first conductor 3A and the second conductor 3B. For example, the strip 5 can be made of rubber having good electrical insulating properties and also good moisture resistance.

Fig. 1D shows a schematic illustration of a part of a second alternative embodiment of the device according to the invention. This second alternative embodiment differs from the first alternative embodiment shown in fig. 1C in that the outer ends of the first and second conductors 3A, 3B are formed in a complementary manner (in this example, two interengaging hooks) to more securely hold the strip 5 between the first and second conductors 3A, 3B.

Fig. 2 shows a schematic illustration of an embodiment of an electronic circuit 10 for use in a meter (e.g., meter 6 of fig. 1A) according to the present invention.

The circuit 10 is supplied via a terminal Vcc, wherein during operation a voltage level, also referred to as Vcc-, may be supplied as a power supply, which may be for example between 2 and 15 volts. The circuit 10 includes an Integrated Circuit (IC)11, where the Integrated Circuit (IC)11 is used to determine a time interval (timing integrated circuit or IC), e.g. based on a 555IC as developed by Signetics. Those skilled in the art will appreciate that a wide variety of electronic components may alternatively be used, but such embodiments are practical because they utilize standard components.

Power is supplied to the IC 11 in the terminal 8(Vcc) and is also used to control the terminal 4 having a negative RESET function (-RESET). If terminal 4 is grounded, IC 11 is reset.

The power flows through resistor R1 and is further connected to terminal 7(DIS) of IC 11, terminal 7 acting as an open collector. The remaining voltage flows further from terminal 7 through resistor R2 and is further connected to terminal 6(THR) and terminal 2(TRIG) of IC 11, which terminal 6(THR) and terminal 2(TRIG) may be used during operation to determine the start and end of the time interval.

The remaining voltage flows from resistor R2 through capacitor C_eqTo Ground (GND). If the conduit is non-conductive, the capacitor C_eqCan be considered as capacitor 4C only, or if the conduit is conductive, capacitor C_eqViewed on the one hand as a parallel circuit of the capacitor 4C and on the other handIs regarded as a parallel circuit of a first additional capacitor 4A and a second additional capacitor 4B.

The ground is also connected to the terminal 1(GND) of the IC and via a capacitor 13 (preferably having a low capacitance, e.g. 10nF) to the terminal 5(CTRL) of the IC 11. Terminal 1 may be used during operation as a ground reference voltage (e.g., 0 volts). Terminal 5 may be used during operation to provide control access to an internal voltage divider in IC 11 to (indirectly) control the duration of the time interval.

An output signal 12(OUT) is provided via terminal 3(OUT) of IC 11. During operation, the output signal 12 takes the form of a continuous current of rectangular voltage pulses, the current having a certain frequency (f)_Out). The frequency f_OutCan be determined as follows: f. of_Out＝(C_eq·(R1+2·R2)·ln(2))。

By this configuration, circuit 10 can be used as a stable multivibrator, i.e., an electronic oscillator, which generates a frequency value f_OutFrequency value f_OutRepresenting the capacitive effect of the device as discussed with respect to fig. 1A. The frequency value f can also be obtained, if desired, for example using a microcontroller (not shown)_OutOptionally to capacitance expressed in farads, but those skilled in the art will appreciate that this additional step is not a necessary step to be able to approximate the capacitive contribution of the capacitor or capacitors. Those skilled in the art will also appreciate that many other configurations of meters are possible. For example, the meter may be configured to generate a waveform, such as a sinusoidal waveform or a square waveform, and measure the response.

Fig. 3 shows a schematic illustration of an alternative embodiment of an electronic circuit 20 for use in a meter (e.g., the meter 6 of fig. 1A) according to the present invention.

The circuit 20 includes an operational amplifier 21 and a comparator 22. The output of the operational amplifier 21 is connected in series to the capacitor C, according to an observation similar to that carried out above with reference to fig. 2_eq. Capacitor C_eqTo the negative input terminal of the operational amplifier 21. Capacitor C_eqAnd also to the output terminal of the comparator 22 via a resistor R1. In addition, a capacitor C_eqIs connected to the positive input terminal of the comparator 22 via a resistor R3, which is in turn connected to the output terminal of the comparator 22 via a resistor R2. The positive input terminal of the operational amplifier 21 is connected to the negative input terminal of the comparator 22 via a resistor R4. An output terminal of comparator 22 produces an output signal 23 (Out). This output signal 23 can be used in a similar way as the output signal 12 in fig. 2, since they are both pulses.

Fig. 4 shows a schematic illustration of another embodiment of an electronic circuit 40 for use in a meter (e.g., meter 6 of fig. 1A) according to the present invention.

Circuit 40 includes an Integrated Circuit (IC)48 having a terminal 45, a terminal 46, and a terminal 47. A first pole 41 of the capacitor is coupled to an input terminal 47. The first pole 41 is coupled to the second pole 42 of the capacitor via a capacitive coupling 44. Source 43 drives a variable frequency ac voltage or variable frequency ac current through capacitive coupling 44. IC 48 measures its amplitude variation (e.g., at output terminal 45) and/or phase variation (e.g., at output terminal 46), in particular, its phase shift.

Fig. 5 shows a schematic illustration of another embodiment of an apparatus for measuring the coagulation and/or corrosion progress of a catheter 1. The device comprises an insulator 2 extending around the conduit, a first conductor 3A, a second conductor 3B and a third conductor 3C. The first conductor 3A and the second conductor 3B are arranged such that at least a portion of the insulator 2 is located between the catheter 1 and the first conductor 3A and the second conductor 3B, such that the first conductor 3A forms a first pole of the capacitor 4 and the second conductor 3B forms a second pole of the capacitor 4. The third conductor 3C is arranged such that at least a further portion of the insulator 2 is located between the conduit and the second and third conductors 3B, 3C and such that the second conductor 3B forms a first pole of a further capacitor 4, the third conductor 3C forms a second pole of the further capacitor 4 and said further portion of the insulator 2 comprises a further capacitive coupling located between the first and second poles of the capacitor 4. The first conductor 3A, the second conductor 3B and the third conductor 3C are arranged at a distance from each other, seen in the longitudinal direction of the catheter.

The apparatus further comprises a plurality of meters 6, the plurality of meters 6 being configured to determine a plurality of conductors representing adjacent conductorsThe value of capacitive coupling between body 3A, conductor 3B and conductor 3C. A first meter 6 may be connected between the first conductor 3A and the second conductor 3B, a second meter 6 may be connected between the second conductor 3B and the third conductor 3C, etc. Between the first conductor 3A and the second conductor 3B, an intermediate outer layer 3I (e.g., a conductive intermediate layer) may be arranged around the insulator 2. The conductive outer layer 3I may be grounded or floating. Similar intermediate outer layers 3I may be disposed between other adjacent conductors 3B, 3C, etc. The intermediate conductive layer may serve as a support for the meter 6. Preferably, each conductor 3A, 3B and 3C extends over a first length L1 as viewed in the longitudinal direction, and the surface area of each conductor is at least 10%, preferably at least 25%, more preferably at least 50% of the surface area of conductor 1 along the first length. Note that the conductor 3A, the conductor 3B, and the conductor 3C may extend to different lengths. The conductors 3A, 3B and 3C may be formed as sleeves so that the surface area along the length L will be even larger than the surface area of the conduit. However, to save material, conductor 3A, conductor 3B and conductor 3C may be formed as interconnected multiple conductive layer elements, see also the example of fig. 6. Although not shown in fig. 5, similar to what has been shown and described in fig. 1A and 1B, the strip 5 covering the area of the insulator 2 may be arranged between the first conductor 3A and the intermediate layer 3I and between the intermediate layer 3I and the second conductor 3B. Such a device has the advantage that a large part of the pipe can be detected with a relatively small number of simple meters 6. Although not shown in the drawings, it will be clear to those skilled in the art that the intermediate layer 3I and the catheter 1 may be grounded or floated, or a combination of grounded and floated may be used as appropriate. It is noted that the capacitive coupling between the first conductor 3A and the second conductor 3B may comprise a series/parallel connection of a plurality of "capacitors" 4A to "capacitors" 4F to create an equivalent capacitance C_eq(corresponding to capacitor 4 in fig. 5). This is shown in fig. 6, in fig. 6 it is assumed that the intermediate layer 3I and the duct 1 are made of an electrically conductive material.

The length L1 of the conductors 3A, 3B and 3C may be, for example, between 0.5m and 10m, depending on the type of conduit to be insulated. The diameter of the insulator may for example be between 5mm and 1200mm, preferably between 10mm and 500 mm. The distance d between the first conductor 3A and the second conductor 3B may be, for example, between 1cm and 200cm, preferably between 2cm and 150 cm.

Fig. 7 shows an embodiment of an apparatus comprising a plurality of insulator segments 2A, insulator segments 2B, etc. Insulator sections 2A, 2B (also referred to as insulating elements) together form the insulator of the device. The insulator segments 2A, 2B extend around the catheter 1. A first conductor comprising an interconnected plurality of conductive layer elements 3A 'and a second conductor comprising an interconnected plurality of conductive layer elements 3B' are arranged on or in the first insulator segment 2A and the second insulator segment 2B, respectively. The conductive layer elements 3A ', 3B' may be elongated strip-like elements extending along the longitudinal direction of the catheter 1 and arranged at a distance from each other around the catheter 1 as seen in a cross-section perpendicular to the longitudinal direction. Preferably, each conductor extends over a first length L1 as viewed in the longitudinal direction, and the total surface area of each conductor (i.e. of all strips 3A 'or of each conductor of strips 3B') is at least 10%, preferably at least 25%, more preferably at least 50% of the surface area of conductor 1 along the first length. The meter 6 may be connected between the first conductor 3A 'and the second conductor 3B'. The space between the insulator segments 2A, 2B may be filled with an insulating paste or paste. Furthermore, any features disclosed above with respect to other embodiments may also be applicable to the embodiment of fig. 7.

Fig. 8A to 8D show different possible embodiments for performing measurements. In the embodiment of fig. 8A, a plurality of conductors 3A to 3F are arranged adjacent to each other on or in an insulator 2, the insulator 2 being arranged around a conduit 1 having an axis a. The first meter 6 is connected between the first conductor 3A and the third conductor 3C, the second meter 6 is connected between the second conductor 3B and the fourth conductor 3D, and the third meter 6 is connected between the third conductor 3C and the fifth conductor 3E. Such a setting may provide a high degree of accuracy. In fact, for example, a leak below the conduit 3C can be detected by both the first gauge 6 and the third gauge 6. The embodiment of fig. 8B is similar to the embodiment of fig. 6, but the intermediate conductive layer 3I has the same length as the conductors 3A, 3B and 3C. In the embodiment of fig. 8C, there are no intermediate unconnected layers, and each pair of adjacent conductors 3A, 3B, 3C, 3D, etc. are connected to a meter 6. In the embodiment of fig. 8D, conductors 3A, 3B, 3C, etc. are arranged at different distances from the catheter 1. For example, conductors 3A, 3C, 3E may be disposed between first and second insulating layers of insulator 2, whereas conductors 3B and 3D are disposed on the outer surface of the insulator. Optionally, the gauge 6 may also be arranged on the outer surface of the insulator 2. In an alternative embodiment, all of the insulators 3A to 3E may be arranged between the first insulating layer and the second insulating layer of the insulator 2. More generally, in the embodiment of fig. 8A to 8D, all or some of the conductors 3A, 3B, etc. or 3A, 3B, etc. may be embedded in the insulator 2.

Fig. 9 shows an embodiment of an assembly of insulating elements 100A, 100B, 100C, 100D, 100E. Each of the insulating elements 100A to 100E includes an insulator sleeve 2A to 2E, the insulator sleeve 2A to 2E configured to extend around the guide tube 1, the conductors 3A to 3E embedded in the insulator sleeve 2A to 2E, and at least one connecting element 103, 104 extending through the insulator sleeve 2A to 2E to the insulator sleeve 2A to 2E from the conductors 3A to 3E. The conductors 3A to 3E may be shaped as conductor sleeves having a length L1 less than the length Li of the insulator sleeves 2A to 2E, and may be fully embedded in the insulator sleeves 2A to 2E. In an alternative embodiment, the conductors 3A to 3E may comprise a plurality of interconnected conductive layer elements, for example as disclosed in connection with fig. 7, wherein the plurality of interconnected conductive layer elements are embedded in the insulator sleeve 2A to 2E. The insulator sleeves 2A to 2E may include a first insulator layer 101 and a second insulator layer 102, and the conductor layers 3A to 3E may be disposed between the first insulator layer 101 and the second insulator layer 102. Adhesion between first insulator layer 101 and second insulator layer 102 may be improved by using multiple conductive layer elements that are interconnected rather than a complete sleeve for conductors 3A-3E.

The gauge 6 may be disposed on an insulator sleeve 2D, such as the illustrated insulator element 100D. The meter 6 may be connected to adjacent conductors 3C, 3E of the insulating elements 100C, 100E as shown, but may also connect conductors included in the insulating elements (not shown in fig. 9). The gauge 106 may be configured to wirelessly transmit the measured values to a wireless receiver of the monitoring controller. To facilitate connection, for each of the insulating elements 100A to 100E, the connector elements 103, 104 pass from the insulator 2A to the outer surface of the insulator 2E to the conductors 3A to 3E. In the illustrated embodiment, two connector elements 103 and 104 are provided, one at each end of the conductors 3A to 3E, but only one connector element may be provided or more than two connector elements may be provided. The connector elements 103, 104 may be used to interconnect adjacent conductors. For example, conductor 3A is electrically connected to conductor 3B through connector element 104 of insulating element 100A, connecting wire 110, and connector element 103 of insulating element 100B.

Fig. 10 shows another embodiment of the insulating element 100. The insulating member 100 includes: an insulator sleeve 2 configured to extend around the conduit 1; a first conductor 3A and a second conductor 3B, both embedded in the same insulator sleeve 2; and a plurality of connecting elements 103, 104, 105 and 106 extending from the first conductor 3A and the second conductor 3B through the insulator sleeve 2 to the outer surface of the insulator sleeve 2. The conductors 3A, 3B may be shaped as conductor sleeves at a distance d from each other, seen in the axial direction, and may be completely embedded in the insulator sleeve 2. In an alternative embodiment, the conductors 3A, 3B may comprise a plurality of interconnected conductive layer elements, for example as disclosed in connection with fig. 7, wherein the plurality of interconnected conductive layer elements are embedded in the insulator sleeve 2. The insulator sleeve 2 may include a first insulator layer 101 and a second insulator layer 102, and the conductor layers 3A to 3E may be arranged between the first insulator layer 101 and the second insulator layer 102.

The gauge 6 may be arranged on the insulator sleeve 2. The meter 6 may be connected between the first conductor 3A and the second conductor 3B as shown, but may also be connected to the conductors of adjacent insulating elements. The gauge 106 may be configured to wirelessly transmit the measured values to a wireless receiver of the monitoring controller. To facilitate the connection, the connector elements 103, 104, 105, 106 pass through the second insulating layer 102 from the conductors 3A, 3B. In the embodiment shown, two connector elements 103 and 104 are provided per conductor, one at each end of the conductors 3A, 3B, but only one connector element may be provided per conductor 3A, 3B or more than two connector elements may be provided. Connector elements 105, 106 may be connected to the meter 6 and the other connector elements 103, 104 may be used to interconnect adjacent insulating elements 100.

Fig. 11 shows an embodiment of an apparatus and method for measuring the deterioration of a surface layer 200 on a catheter 1. The surface layer 200 may be a coating, a cover layer, an oxide layer, or the like. Typically, the thickness ts of the surface layer is less than the thickness tc of the wall of the catheter 1. For example, the thickness ts of the surface layer 200 may be less than 10mm, preferably less than 9mm, more preferably less than 8 mm. The thickness ts of the surface layer 200 may also be in the order of microns, for example, about 100. The thickness ti of the insulator may be, for example, between 5mm and 500mm, preferably between 9mm and 250 mm. For example, the surface layer may be a corrosion resistant surface layer or another protective surface layer, such as cathodic protection. The device comprises: an insulator 2 extending around the surface layer 200 on the catheter 1; a first conductor 3A and a second conductor 3B at a distance from the first conductor, said first conductor 3A and second conductor 3B being arranged such that at least a part of the insulation is located between the guide tube and the first conductor and between the guide tube and the second conductor; and a meter 6 configured to determine a value representative of an impedance 204C of a surface layer underlying the portion of the insulator 2. By using the first conductor 3A and the second conductor 3B as described above, any external noise will be present on both the first conductor and the second conductor and will be cancelled out as the measurement is a differential measurement performed between the first conductor 3A and the second conductor 3B.

The meter 6 may comprise an electrochemical impedance spectroscopy meter or any other AC impedance measurement. Using such measurements, the phase and amplitude of the impedance are obtained as a function of frequency. When the surface layer 200 deteriorates, the impedance 204C of the surface layer changes, which results in a change in the phase measurement and a change in the amplitude measurement. This is shown in fig. 12A and 12B. Fig. 12A schematically shows a measurement curve 1203 for the phase without degradation and a curve 1204 for the phase with degradation, showing the change in the phase curve due to degradation of the surface layer 200. Fig. 12B schematically shows a measurement curve 1201 for the amplitude without degradation and a curve 1202 for the amplitude with degradation, showing the reduction of the amplitude due to the degradation of the surface layer 200. Other AC or DC meters are possible as long as they can determine a value representative of the impedance 204C of the surface layer 200 below the portion of the insulator 2. Other impedances 104A, 104B, 204A, 204B, 104C (shown in the simplified model in fig. 11) will also affect the measurement, but changes in the measured values will represent degradation of the surface layer. The apparatus may further comprise a monitoring controller configured to analyze the degradation of the surface layer based on the one or more values determined by the meter 6.

Preferred and exemplary features of the above disclosed apparatus and method for measuring the progress of coagulation and/or corrosion of a conduit may also be present in the apparatus and method for measuring the degradation of a surface layer on a conduit. More specifically, the apparatus of fig. 1 to 10 may also be used to measure the deterioration of a surface layer on a catheter when a suitable meter 6 is selected. Furthermore, the arrangement/method may be combined, i.e. the same arrangement may be provided with a first gauge 6 to determine a value representative of the capacitive coupling 4C shown in fig. 1A and a second gauge 6 to determine a value representative of the impedance 204C of the surface layer below the portion of the insulator 2. In practice, the same insulator 2 and first and second conductors 3A, 3B may be used to perform both measurements.

In the embodiments of fig. 5 and 11, the intermediate layer 3I may be used to mount one or more meters 6 and/or one or more power supplies for powering one or more meters 6. Furthermore, this intermediate layer 3I can be used for mounting a support to fix the pipe 1 together with the insulator 2 to the wall. However, a device (set-up) without an intermediate layer may also be used, for example, as shown in fig. 1A to 1B and fig. 9.

It will be understood by those skilled in the art that many modifications and variations may be envisaged within the scope of the invention, which is limited only by the appended claims.