Arrangement having first space and first seal

Abstract

The invention relates to a device (10) having a first space (12) and a first seal (14) which seals the first space from a second space (16). According to the invention, the device comprises a control unit (28), which is designed to measure a voltage between the metal regions and / or a resistance between the metal regions and / or a current between the metal regions and / or a conductance between the metal regions, and two metal regions (18, 20) located in the first space, the control unit being designed to measure the voltage between the metal regions and / or the resistance between the metal regions and / or the current between the metal regions and / or the conductance between the metal regions, the two metal regions are made of different metals and / or the device (10) comprises an electrically conductive path from one of the two metal regions to the other of the two metal regions, the electrically conductive path extending in at least two different metals.

Description

TECHNICAL FIELD

[0001] The invention relates to a device having a first space and a first seal sealing the first space from a second space. BACKGROUND

[0002] One problem is that water in various states (e.g. water can be in its dissolved, emulsified or free state within a lubricant) can gradually accumulate unnoticed inside a mechanical system (e.g. due to an unexpected seal failure). This raises the problem that this is a hidden threat to the system (e.g. causing corrosion, excessive wear and hydrogen embrittlement) until the real problem is detected, such as a malfunctioning or failure of the mechanical system. The immediate consequence is that the operation of the asset has to be interrupted to perform passive maintenance. All this leads to a sudden increase in the asset’s total cost of ownership, which can be quite high in some cases (e.g. offshore installations).

[0003] The Karl Fischer (KF) titration measurement procedure is a standardized analysis procedure that can track the amount of water in a grease sample (although specific measurement equipment is required). However, one of the main bottlenecks of this offline method is the need to pause the application to take out the grease sample to analyze it in a laboratory.

[0004] Document WO 2014 / 094812 A1 discloses a bearing having a seal sealing a space of the bearing from a further space. A grease condition monitoring method is described. Documents WO 2014 / 094813 A1, US2018 238851 and US2018 038 417 describe further related prior art.

[0005] Furthermore, especially in the case of applications with high value assets, the sealing system (single or multiple sealing configurations) is overdesigned to delay water ingress, thereby minimizing the risk of contaminants reaching critical spaces of the application. Another approach is to perform preventive maintenance very early before the seal is expected to fail, however, this comes at a significant financial cost. SUMMARY

[0006] The problem of the present invention is in particular to provide efficient protection against damage caused by liquid ingress. According to the present invention, this problem is solved by the features of claim 1 and claim 9, while advantageous embodiments of the present invention are described in the dependent claims.

[0007] The present invention relates to a device having a first space and a first seal, which seals the first space from a second space.

[0008] It is proposed that the device comprises a control unit and two metal regions located in the first space, the control unit being designed to measure a voltage between the metal regions and / or a resistance between the metal regions and / or a current between the metal regions and / or a conductance between the metal regions, wherein the two metal regions are made of different metals and / or the device comprises a conductive route from one of the two metal regions to the other of the two metal regions, which conductive route runs at least in two different metals. By the fact that the route "runs at least in two different metals", it is in particular to be understood that a first part of the route is made of a first metal and a second part of the route is made of a second metal, which is different from the first metal. In this way, efficient protection can be provided against damage caused by liquid ingress. In particular, a change in voltage and / or current and / or resistance and / or conductance can be used to notice the presence of a liquid caused by a seal failure.

[0009] In particular, the control unit can comprise a processor and a memory, in which an operating program is saved. In particular, the control unit can comprise one or more sensors.

[0010] Advantageously, the metal regions are spaced apart from each other and the control unit is configured to generate a signal when the voltage and / or the current between the metal regions reaches or exceeds a predetermined value. Thereby, a signal can be generated when there is some kind of liquid between the metal regions.

[0011] Furthermore, it is proposed that the predetermined value depends on a difference of an anodic index of the different metals. In this way, it can be identified that there is water between the metal regions.

[0012] Advantageously, the control unit is configured to generate a signal when the electrical resistance reaches or exceeds a predetermined electrical resistance value and / or the electrical conductance reaches or falls below a predetermined electrical conductance value. Thereby, a deterioration of one of the metals due to the presence of an electrolyte can be detected. In particular, the electrolyte can be water.

[0013] Further, it is proposed that at least one of the metal regions has the shape of a ring or a ring segment. In this way, an interaction between the metal region and the liquid can take place in a relatively large area, which means that the presence of the liquid can also be identified in this relatively large area.

[0014] Advantageously, the first seal is part of a second seal of the device. Thereby, a failure of the first seal can be detected when the second seal still functions partially.

[0015] Further, it is proposed that the different metals of the two metal regions have different anodic indices. Thereby, a voltage can be generated, which can be detected, when the space between the two metal regions is filled with water.

[0016] Further, it is proposed that the two different metals have different anodic indices. In this way, a change in the electrical resistance of one of the metals occurs, which can be detected, when water comes into contact with the metal.

[0017] Advantageously, at least one of the metal regions and / or the control unit is integrated into a first seal and / or a second seal of the device. Thus, the device can be constructed with a small number of components.

[0018] Advantageously, an insulator, which is a solid, is located between the two metal regions. Thus, contact between the two metal regions is safely avoided.

[0019] Further, a device having a first space and a seal, in particular a device as described above, is proposed, which seals the first space from a second space, wherein at least one sensor is designed to detect at least one liquid and is located at least partially within the seal. In this way, an effective protection can be provided against damage caused by liquid immersion. In particular, the liquid can be detected at an early stage.

[0020] Furthermore, it is proposed that the sensor is a capacitive sensor. In this way, a high sensitivity and a fast response time can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Further advantages can be taken from the following description of the drawings. In the drawings, embodiments of the application are shown. The drawings, description and claims comprise, in combination, numerous features. The person skilled in the art will also consider these features individually advantageous and will combine them to form useful further combinations.

[0022] Figure 1 A partial axial cross-section through the device according to the application is shown,

[0023] Figure 2 A part of Figure 1 is shown in an enlarged manner,

[0024] Figure 3 A part of Figure 2 is shown in an enlarged manner,

[0025] Figure 4A An exploded view of the carrier and components carried by the carrier is shown, Figure 4B a detail of the carrier is shown in perspective view,

[0026] Figure 5 A cross-section as indicated in Figure 1 is shown,

[0027] Figure 6 A wire in a straight state is shown, and

[0028] Figure 7 A cross-section of one alternative embodiment of the sensor of the device is shown.

[0029] LIST OF REFERENCE SIGNS:

[0030]

[0031] DETAILED DESCRIPTION

[0032] Figure 1A partial axial cross-section through a device 10 according to the application is shown. The device 10 comprises a housing 30, a liner 34 and a shaft 32 which is designed to rotate relative to the housing. The liner 34 is fixed to the shaft in a liquid-tight manner. The device comprises a first seal 14 and a second seal 22. The first seal 14 is part of the second seal 22. The second seal is fixed to the housing 30 in a liquid-tight manner and seals a space 36 of the device against a space 38 outside the device by providing a sealing function between the housing 30 and the liner 34. Alternatively, the liner can be omitted and the sealing function can be provided between the housing and the shaft.

[0033] The first seal 14 seals a space 12 of the device against a space 16 of the device. Each of the spaces 12, 16 is a chamber of the seal 22. The seal 14 abuts against the liner 34. Alternatively, the seal 14 and the liner 34 form a gap ring. The device comprises two metal regions 18, 20 in the space 12. Figure 2 and Figure 3 The metal regions each consist of a wire and have the shape of a ring segment which is almost a complete ring. The ring segments have the same diameter. Furthermore, the device comprises an insulator 24 which is solid between the two metal regions 18, 20. The insulator 24 has the same shape and diameter as the metal regions. The metal regions and the insulator almost completely encircle the shaft in the circumferential direction of the shaft. The device further comprises a carrier 40 which carries the metal regions and the insulator in a way such that the metal regions and the insulator are in contact with a part of the space 12 which is outside the carrier 40. The carrier 40 is located in the space 12. The carrier 40, the metal regions and the insulator together form a sensor 26.

[0034] Furthermore, the device comprises a control unit 28 which is configured for measuring a voltage between the metal regions. The two metal regions are made of different metals which have different anodic indices. For example, the metal region 18 can consist of zinc or tin and the metal region 20 can consist of copper. The metal regions 18, 20 are spaced apart from each other. The control unit 28 is configured to generate a signal when the voltage between the metal regions reaches or exceeds a predetermined value. The predetermined value depends on the difference of the anodic indices of the different metals. For example, the predetermined value can be the difference of the anodic indices of the different metals minus 20% of the difference. When the metal region 18 consists of zinc and the metal region 20 consists of copper, the following occurs when the metal regions are connected with water:

[0035] • At the zinc electrode, an oxidation reaction occurs: Zn(s)→ Zn 2+ + 2e - ; an oxidation potential E 0 = -0.76 V

[0036] • At the copper electrode, a reduction reaction occurs: Cu 2+ + 2e - → Cu(aq); a reduction potential E

[0037] 0 = 0.16 V

[0038] In practice, the voltage difference between the electrodes is slightly lower than the calculated value.

[0039] The seal 22 comprises a further seal 42 that participates in sealing the space 36 from the space 38. If the seal 42 fails, in the case that the space 38 contains water, water will intrude into the space 12. If the metal regions are connected through the water, the voltage builds up between the metal regions, and the control unit will generate a signal that indicates to the user of the device, via the display and / or via an acoustic noise, that there is water inside the space 12. The seals 44, which are part of the seal 22, can still function and provide a seal between the space 36 and the space 38 when there is water inside the space 12. Each of the seals 44 abuts against or establishes a gap ring with the liner 34.

[0040] Optionally, a further sensor, which is structurally identical to the sensor 26, can be placed in the chamber between the seals 44 and / or in the chamber between the seals 42. The further sensor can work in the same way as the sensor 26 with the control unit.

[0041] Figure 4A The sensor 26 is shown in an exploded view.

[0042] Figure 5 A section is shown as indicated in Figure 1 When viewed in the axial direction of the shaft, the carrier 40 contains a gap 46 in the wire support. The end 48 of the metal region 20 is connected to the control unit.

[0043] ​The device can be provided with a further sensor which is structurally identical to the sensor 26, wherein one of the sensors can be located between adjacent seals of the seal 22. The device can then comprise five sensors. It is also possible to equip each chamber of the seal 22 with multiple sensors. The progression of wear can be monitored. This allows the seal to be replaced before the sealing system is fully degraded and extends the service life of the seal. By monitoring the degradation, the right moment to replace the seal can be chosen in time. The control unit can be connected to the monitoring system. This can be a monitoring system which comprises the configuration of the device.

[0044] The sensors can be integrated or placed into the seal 22 and / or the seal 14. For example, more than 50% or more than 75% of the surface of the metal regions 18, 20 can contact the seal 22 and / or the seal 14. The metal regions 18, 20 can be fixed directly to the seal 22 or the seal 14. Furthermore, the control unit 28 can be fixed to the seal and / or can be located within the seal 22.

[0045] The present invention proposes a cost- and energy-efficient solution to inform the owner when water has penetrated into the system, so that appropriate measures can be taken in time.

[0046] The advantage is the ability to detect water leaks, which can extend the service life. Extending the service life reduces the operating costs for the end user.

[0047] In principle, the water leak sensing can be fitted to any sealing system as long as there is sufficient space. This can be used to at least detect the fact of a leak and invoke measures that will avoid further consequential damage.

[0048] The simplicity of the working principle behind the present invention will allow equipping various types of mechanical systems (across many industries) with a method for detecting water ingress. Furthermore, the method is not limited in the size of the application, thus, it is scalable. Especially given that the method requires a relatively low investment cost (material resources) and is energy efficient (i.e. a passive detection method). The length of the electrodes can be adapted to the size of the application.

[0049] Another advantage of the present invention is that it has a positive impact on the maintenance management of the asset and how to make it better. More specifically, looking at the current situation: when there is a sealing barrier in the mechanical system, the unknown condition of this sealing barrier forces the asset owner to either perform a regular maintenance (also called preventive maintenance) according to a fixed schedule or to react as soon as possible with a corrective maintenance (immediate repair / replacement) in case of an unexpected failure of the system. In both cases, the result is a rather high maintenance cost and an impact on the total cost of ownership of the asset, as there is no sensor unit to inform the asset owner that water has entered the system. This is especially true in case of assets that are difficult to access, such as offshore installations.

[0050] Now, the present invention will allow to improve the method for managing the maintenance of the asset, thus maximizing the life of the asset.

[0051] For example:

[0052] In case of a single seal in the mechanical system, then at least the asset owner is informed by the sensor that water ingress is occurring, so that a decision can be taken in time to take the necessary measures, thus minimizing the chance of major damage to the asset.

[0053] In case of multiple seals forming a sealing barrier within the mechanical system, then multiple sensor units can be cleverly positioned within the available space of the sealing system. This is advantageous for the asset owner to adjust / correct the time of the planned maintenance in case of water ingress. More specifically, if water is creeping past the first seal of the sealing system, then one of the sensor units will alert the asset owner. This requires for example a decision that can be taken not to react immediately to not disturb the asset’s operation, as the asset can still be safely operated until the next planned maintenance, as there are still multiple seals being monitored by the placed sensors.

[0054] Another potential advantage of the present invention is that by choosing the right electrode material, it is potentially possible to extend the sensing method to monitor the ingress of other types of liquid contaminants (other than water) in the mechanical system.

[0055] In summary, the important advantage is that the present invention allows the asset owner to have a first insight / indication (albeit indirect) on the water ingress in the mechanical system. This alone can optimize the life of the asset while better mastering (i.e. reducing) its total cost of ownership.

[0056] The device can for example be part of a ship or a tidal turbine. The seal 22 can for example protect a bearing located in the space 36 from water.

[0057] As the metal regions 18, 20 are almost rings, they have a large surface, which means that the risk of them being completely covered by grease, which can affect the function of the device, is low.

[0058] The ends of the metal regions 18, 20 can extend radially outwards towards the control unit in a channel 41 within the carrier Figure 4A and Figure 4B ). The carrier can be made of two halves, which are rings and are clipped together.

[0059] Figure 6 and Figure 7 Alternative embodiments are shown. Essentially the same components, features and functions are generally numbered with the same reference numerals. However, the letter "a" or "b" has been added to the reference numerals of these alternative embodiments in Figure 6 and Figure 7 to distinguish between the embodiments. The following description is essentially limited to the differences with the embodiments in Figures 1 to 5 , whereby reference can be made to the description of the embodiments in Figures 1 to 5 with respect to the components, features and functions that remain the same.

[0060] Another embodiment of the invention differs from the embodiment shown in Figures 1 to 5 in that there is no metal region 18 and no insulator 24. The metal region 20a Figure 6) is a wire, which is composed of segments 50a and segments 52a, which are stringed together in an alternating way: a segment 52a is located behind and in contact with each segment 50a, and a segment 50a is located behind and in contact with each segment 52a. Adjacent segments are fixed to each other in a conductive way. The segments 50a are composed of a first metal. The segments 52a are composed of a second metal, which is different from the first metal. The two different metals have two different anodic indices. For example, the segments 50a are composed of copper, and the segments 52a are composed of zinc. The control unit 28 measures the electrical conductance between the ends of the metal area 20a, which means between the ends of the wire. When the wire is exposed to water, the electrical conductance of the wire deteriorates. Zinc corrodes. The control unit is configured to generate a signal when the electrical conductance reaches or falls below a predetermined electrical conductance value. One variant of this embodiment is to create the metal area 20a differently ( / generate): for example, by winding a zinc wire on a copper wire.

[0061] Figure 7 A cross-section of one alternative embodiment of the sensor 26b is shown. The sensor 26b is also ring-shaped.

[0062] Yet another embodiment of the invention has a sensor 26 as shown in Figure 1 , which means that the sensor 26 is located inside the seal 22. This embodiment differs from the embodiment shown in Figures 1 to 5 in that the sensor 26 is a capacitive sensor. When water intrudes into the space 12, the capacitive sensor senses the water. Since the capacitive sensor is connected to the control unit 28, the control unit generates a signal when the capacitive sensor senses the water.

Claims

1. Device (10) having a first space (12) and a first seal (14), which seals the first space from a second space (16), characterized by a control unit (28) and two metal regions (18, 20) in the first space, the control unit (28) being designed to measure a voltage between the metal regions and / or a resistance between the metal regions and / or a current between the metal regions and / or a conductance between the metal regions, wherein the two metal regions are made of different metals and / or the device (10) comprises an electrically conductive line from one of the two metal regions to the other of the two metal regions, which electrically conductive line extends at least in two different metals.

2. Device (10) according to claim 1, characterized by the metal regions (18, 20) being spaced apart from one another and the control unit (28) being configured to generate a signal when the voltage and / or the current between the metal regions reaches or exceeds a predetermined value.

3. Device (10) according to claim 2, characterized by the predetermined value depending on a difference of the anodic indices of the different metals.

4. Device (10) according to at least one of the preceding claims, characterized by the control unit (28) being configured to generate a signal when the resistance reaches or exceeds a predetermined resistance value and / or the conductance reaches or falls below a predetermined conductance value.

5. Device (10) according to at least one of the preceding claims, characterized by at least one of the metal regions (18, 20) having the shape of a ring or a ring segment.

6. Device (10) according to at least one of the preceding claims, characterized by the first seal (14) being part of a second seal (22) of the device (10).

7. Device (10) according to at least one of the preceding claims, characterized by at least one of the metal regions (18, 20) and / or the control unit (28) being integrated into the first seal (14) and / or the second seal (22) of the device.

8. Device (10) according to at least one of the preceding claims, characterized by an insulator (24) between the two metal regions (18, 20) and being solid.

9. Device (10) having a first space (12) and a seal (22), in particular according to at least one of the preceding claims, which seals the first space from a second space (16), characterized by at least one sensor (26) designed to detect at least one liquid and at least partially located within the seal.

10. Device (10) according to claim 9, characterized by the sensor (26) being a capacitive sensor.

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