A pressure compensated electronics module for subsea application

Abstract

It is described a pressure compensated electronics module (1) for subsea application, the module (1) being configured to compensate for variations in ambient pressure and / or temperature (10), the module (1) comprising: - a liquid-filled, first chamber (100); - a gas-filled second chamber (112) accommodating a first set of electronics (110) at a predefined pressure, the second chamber (112) sharing a dividing wall (501) with the first chamber (100); - a compensation device (600) comprising a liquid reservoir being in fluid communication with the first chamber (100) and being in pressure communication with ambient pressure (10,330) allowing a sub-volume of the liquid in the liquid reservoir to flow into and out of the first chamber (100) to allow the liquid inside the first chamber (100) to adopt to ambient pressure and / or temperature; wherein the volume of the liquid reservoir is at least the sum of the volume of the second chamber (112) and said sub-volume.

Description

[0001] A PRESSURE COMPENSATED ELECTRONICS MODULE FOR SUBSEA APPLICATION

[0002] Technical Field

[0003] The present disclosure relates to a pressure compensated electronics module for subsea application. The pressure compensated electronics module is configured to compensate for variations in ambient pressure and / or temperature both when the ambient fluid is air and when the ambient fluid is liquid.

[0004] In particular, the present invention relates to an apparatus according to the preamble of claim 1.

[0005] Background

[0006] Subsea modules are commonly used to operate various components subsea. The subsea modules normally comprise some electric components. Most electric components are sensitive to seawater since the seawater will eventually short-circuit the electrical connections. Therefore, the electric components are normally put in water tight chambers filled with oil. In order to prevent water ingress into the oil chambers, as well as not having to dimension the seals etc. for too large differential pressures, the chambers are normally pressure compensated against the pressure and temperature variations of the seawater at the currently applicable sea depth. The electric components arranged in such chambers thus have to be able to operate under the relatively high pressures at the applicable sea depth, which may be up to 1000s of meters deep.

[0007] However, since all electric components cannot operate under the pressures experienced at these sea depths, the most pressure sensitive subsea electric components are normally protected within 1 atm chambers.

[0008] EP 2169690 Bl relates to a pressure compensator configured to compensate volume variations of an insulation medium of a subsea installation, comprising a first bellows chamber comprising a first bellows part. The first bellows chamber is in flow connection with an insulation medium chamber of the subsea installation and the walls of the first bellows chamber are configured to separate the insulating medium from surroundings. The first bellows chamber is surrounded by a second bellows chamber comprising a second bellows part. The second bellows chamber is configured to form a closed intermediate space around the first bellows chamber. The walls of the second bellows chamber are configured to separate at least the bellows parts of the first bellows chamber from the surrounding sea water. The second bellows chamber is further filled with an intermediate medium. The subsea installation may be a subsea transformer. The subsea transformer comprises a transformer unit and a tank. The tank is filled with insulation medium, i.e. transformer oil. The tank forms an insulation chamber around the transformer unit.

[0009] A disadvantage of the prior art solution is that in case there is leakage of insulation medium into the transformer unit, the compensating function of the compensator may be lost. This may lead to possible ingress of seawater short-circuiting the electronics.

[0010] It is therefore an objective of the invention to provide a subsea module solving the above stated problem.

[0011] Summary of the invention

[0012] The invention is defined in the attached claims.

[0013] The invention relates to a pressure compensated electronics module for subsea application where there is a need for a subsea control module, or modules with electronics, as for instance electric actuators. Subsea application may involve e.g.:

[0014] - hydrocarbon (i.e. oil, gas condensate exploration, production and / or processing),

[0015] - carbon capture storage (CCS),

[0016] - hydrogen applications.

[0017] The present invention relates to a pressure compensated electronics module for subsea application, the module being configured to compensate for variations in ambient pressure and / or temperature, the module comprising: a liquid-filled, first chamber; a gas-filled second chamber accommodating a first set of electronics at a predefined pressure, the second chamber sharing a dividing wall with the first chamber; a compensation device comprising a liquid reservoir being in fluid communication with the first chamber and being in pressure communication with ambient pressure allowing a sub -volume of the liquid in the liquid reservoir to flow into and out of the first chamber to allow the liquid inside the first chamber to adopt to ambient pressure and / or temperature; and wherein the volume of the liquid reservoir is at least the sum of the volume of the second chamber and said sub -volume.

[0018] If the dividing wall leaks, the volume of the at least one compensation chamber will be sufficient to replace the liquid in the first chamber having entered the second chamber due to the leak, and allow the at least one compensation chamber to function as a pressure compensation entity also after the rupture.

[0019] The dividing wall is thus between the first chamber and the second chamber such that a first side of the dividing wall faces the first chamber and a second side of the dividing wall faces the second chamber. The skilled person will understand that there will be some liquid in the pipes or piping between the different components of the compensation device. With pipes or piping one should also understand bores in a body. The skilled person will also understand that the compensation device can be made without pipes or piping between the different components in a case where the first and the second chamber is made in a block of material, and the compensation device is made in an open space or large diameter bore in the block of material with a smaller diameter bore connecting the inner end of the large diameter bore with the first chambers. Where there then within the large diameter bore is provided two barriers in series connection.

[0020] The compensation device includes any pressure chambers and pipes or piping in fluid communication with the first chamber.

[0021] The liquid reservoir is to be understood as the whole liquid volume present in the compensation device. The volume of liquid in the liquid reservoir is thus variable since it depends on how much of the liquid in the liquid reservoir that has flowed into the first chamber to compensate for the ambient pressure and / or temperature.

[0022] The sub-volume can be seen as the active pressure -compensating volume. The active pressure-compensating volume may for example be over where a barrier is moving due to the pressure -compensation, from one end position of the barrier to another end position of the barrier.

[0023] Ambient pressure and temperature are the pressure and temperature of the fluid surrounding the module. Surrounding fluid is typically sea water when the module is deployed subsea but could also be atmospheric air, e.g. when the module is under transportation.

[0024] The at least one compensation chamber is at least partly liquid-filled, meaning that there is preferably always at least some liquid within the chamber. During transport of the module, i.e. when surrounded by ambient air, the compensation chamber will comprise both liquid and air. However, when the module is submerged, the compensation chamber will comprise liquid for pressure compensation as well as sea water.

[0025] The electric source for the electric components of the pressure compensated electronics module are preferably batteries. The batteries may be arranged inside the pressure compensated electronics module. The electric source may also be an umbilical or other connected electric line which can transfer both power and or signals. In case of malfunction due to a leakage into the second chamber resulting in malfunctioning of the first set of electronics, the pressure compensated electronics module is preferably configured to submit information topside.

[0026] The first set of electronics are typically sensitive to high pressure. I.e. the first set of electric components does not withstand pressure. Therefore, the second chamber is preferably hermetically sealed and filled with nitrogen. However, since the dividing wall comprises electric lead-throughs interconnecting the electronics in the second chamber with electronics in the first chamber, the dividing wall is more prone to leaks than other sections of the second chamber. Generally, any joining of two elements is being more prone to leakage than a body of material as such. The second chamber is also comprised of two joining parts which are hermetically sealed.

[0027] The sub-volume, i.e. the pressure-compensating volume, can be selected based on a variety of parameters, and will be part of a daily routine work of a person skilled in the art, the parameters may include:

[0028] - volume of the first chamber,

[0029] - volume of the second chamber,

[0030] - maximum expected ambient pressure and temperature, e.g. hydrostatic column on expected water depth, outside temperature,

[0031] - properties of the liquid in the first chamber and in the compensation chamber.

[0032] The liquid reservoir may be in pressure communication with an ambient fluid via a first movable pressure compensation part exposed to ambient pressure on one side and the pressure of the liquid inside the first chamber on the other side.

[0033] The first movable pressure compensation part may be a bladder, bellows, a piston or a membrane.

[0034] The liquid in the first chamber and the liquid in the liquid reservoir may be the same liquid.

[0035] The first chamber accommodates a second set of electronics. The second set of electronics can operate under pressure. I.e. the second set of electronics can withstand pressure and can be covered by, or submerged in, the liquid in the first chamber.

[0036] The pressure compensated electronics module may comprise a gas -filled third chamber accommodating a third set of electronics at a predefined pressure. The third chamber may be sharing a dividing wall with the first chamber.

[0037] The second and the third chamber may have the same volume. Alternatively, the volumes may be different. The compensation device thus has to be designed in accordance with the largest of the second and third chamber in order to make sure that it can still provide its compensation function if there is a leakage into the largest of the second and third chamber such that it is filled with liquid. Alternatively, the compensation device may be designed in accordance with the combined volume of the second and third chamber if there is a need to be able to compensate if both second and third chamber have developed a leak.

[0038] The first set of electronics in the second chamber and the third set of electronics in the third chamber may be redundant copies. Redundant copies mean that the first set of electronics in the second chamber and the third set of electronics in the third chamber are the same such that if one of the second chamber or the third chamber is filled with liquid, the electronics in the other chamber is still operable and capable of performing required functions. These redundant copies are often referred to as A and B. This solution provides an additional advantage in that the pressure compensated electronics module can maintain its functions both in terms of operating the subsea component as well as pressure compensation even though one of the second or third chambers have developed a leak such that it is filled with liquid from the first chamber.

[0039] The module may comprise a second movable pressure compensation part arranged inside the liquid reservoir, and the first movable pressure compensation part and the second movable pressure compensation part may be arranged in series connection.

[0040] When the pressure compensated electronics module is to be used there is normally a requirement to have two barriers. The two barriers, i.e. a first movable barrier and a second movable barrier, are then formed by the first and second movable pressure compensation parts, respectively. When the first or the second movable barrier damages or break, it opens up the barrier it represents, however the module still has the other barrier intact. Thus, the module has one source of error, i.e. one of the components may malfunction while the module is still able to perform its function.

[0041] The compensation device may comprise:

[0042] - a first compensation chamber in pressure communication with the ambient fluid via the first movable pressure compensation part, the first compensation chamber may be configured to hold a fraction of the liquid of the liquid reservoir at least equal to the sum of the volume of the second chamber and said sub -volume, and

[0043] - a second compensation chamber arranged in series connection between the first chamber and the first compensation chamber.

[0044] The second compensation chamber may be completely liquid-filled.

[0045] A volume of the second compensation chamber may be divided in two by the second movable pressure compensation part. The second compensation chamber may be configured to hold a fraction of the liquid reservoir at least equal to the sub-volume. I.e., both the first compensation chamber and the second compensation chamber hold at least a liquid volume equal to or larger than the sub -volume such that the compensation device as a whole can still compensate for variations in ambient pressure and / or temperature also after a part of the liquid in the liquid reservoir has escaped into the second chamber or the third chamber due to e.g. leakage.

[0046] The second compensation chamber may be configured to hold a fraction of the liquid reservoir at least equal to the second chamber.

[0047] The first or second movable pressure compensation part may be configured to be damaged or break at a given pressure difference across the movable pressure compensation part. This pressure difference is created as the fluid within the first chamber leaks into the second (or the third chamber if the third chamber is present) . The first or second movable pressure compensation part can be a burst disk which can break at a predefined differential pressure difference. Alternatively, it can be a bladder, a membrane, a bellows or similar which can rupture, for instance when forced against a sharp edge or at a given pressure difference or extension of the bladder, membrane, or bellow or similar. For example, there may be a sharp edge somewhere in the compensation device which assists in rupturing the second movable pressure compensation part.

[0048] In yet a further alternative there may be arranged a bypass line between the two sides of the movable pressure compensation part wherein it can be arranged a relief valve or a burst disk in the bypass line. The relief valve or a burst disk may be configured to open and allow the liquid to bypass the movable pressure compensation part without damaging that part as such.

[0049] The module may comprise:

[0050] - a bypass line bypassing the second movable pressure compensation part,

[0051] - an element arranged in the bypass line, and wherein the element may be configured to open, be damaged or break.

[0052] The element may comprise a bladder, a bellows, a burst disc, a relief valve, a membrane.

[0053] In a two barrier system with a first and a second movable barrier part, at least one of these barrier parts needs to be able to operate and move and pressure compensate for a volume at least equal to a volume which include the volume of the second and / or third chamber in addition to the sub-volume. The other barrier part may be set to be operable only for the sub-volume and then either set to break or there being a bypass line that opens at given a pressure difference to allow fluid to bypass the barrier part without breaking the barrier part as such but opening the barrier. There is also an embodiment where both movable barrier parts are designed to operate, move and pressure compensate for a volume at least equal to the volume of the second and / or the third chamber in addition to the sub-volume. In such an instance neither of the barriers will break if there is a leakage into one of the second or third chamber.

[0054] The compensation device may comprise:

[0055] - a first compensation chamber in pressure communication with the ambient fluid via the first movable pressure compensation part, the first compensation chamber may be configured to hold a fraction of the liquid of the liquid reservoir at least equal to the sum of the volume of the second chamber and said sub -volume.

[0056] The second movable pressure compensation part may be arranged inside the first compensation chamber or in a direct continuation of the first compensation chamber.

[0057] In other words, the compensation device may comprise only one compensation chamber and the one compensation chamber may comprise the first movable pressure compensation part and the second movable pressure compensation part. As stated above, the first compensation chamber is then configured hold a fraction of the liquid of the liquid reservoir which is at least equal to the sum of the volume of the second chamber and said sub-volume.

[0058] The dividing wall may comprise electrical lead-throughs. The electrical throughs may interconnect the first set of electronics accommodated in the gas-filled second chamber and the second set of electronics accommodated in the first chamber.

[0059] The dividing wall may be a penetrator plate. The penetrator plate may provide electrical connections between the first set of electronics and the second set of electronics and, if a third chamber with a third set of electronics is present, between the third set of electronics and the second set of electronics within the first chamber. There may also be other methods of transferring signals between the first and second or third chamber. Anyhow it is where parts are joined that there is an additional risk of leakage.

[0060] It is further described a pressure compensated hydrocarbon production and / or processing module for subsea applications, the module being configured to compensate for pressure and / or temperature variations in an external environment surrounding the module, the subsea module comprising:

[0061] - a first chamber accommodating a first set of electronics and having a first volume, the first chamber being configured to hold a first gas at a first pressure;

[0062] - a second chamber having a second volume, the second chamber being configured to hold a liquid at a second pressure;

[0063] - a dividing wall separating the first chamber and the second chamber;

[0064] - a pressure compensation module comprising: a chamber having a chamber volume, the chamber volume being configured to hold a first variable volume of a pressure compensation liquid which is in pressure communication with the second chamber, and a second variable volume of a fluid which is in pressure communication with the external environment, wherein the first and second variable volumes are separated by a movable pressure compensation part, wherein the compensation part is movable within a first operating range and a second operating range, wherein: the first operating range is represented by a first variable compensation liquid volume of pressure compensation liquid within the chamber for compensating against the pressure and / or temperature variations in the external environment, and the second operating range is represented by a second variable compensation liquid volume of the pressure compensation liquid within the chamber for compensating against the pressure and / or temperature variations in the external environment (10), and wherein a difference in volume of compensation liquid within the chamber between the first operating range and the second operating range is equal to or larger than the volume of the first chamber.

[0065] It is further described a subsea module configured to be compensate for pressure and / or temperature variations in the surroundings, the subsea module comprising:

[0066] - at least one first chamber accommodating a first set of electronics within a sealed off first volume, the first chamber being configured to hold a first gas at atmospheric pressure;

[0067] - an outer chamber having a third volume, with a sealing system towards the surroundings, encompassing the at least one first chamber, the third chamber being configured to hold a liquid being pressure compensated in relation to the surroundings, through

[0068] - a pressure compensation module, comprising a movable pressure compensation part, such as a bladder, bellows, a piston, membrane etc., exposed to surrounding pressure on one side and the pressure of the liquid in the outer chamber on the other side, wherein the movable pressure compensation part is airranged to have two different normal operation positions, an outer position and an inner position, where the relative difference between the two positions equals the volume of the first chamber.

[0069] The pressure compensation module may comprise two movable pressure compensation parts.

[0070] Above-discussed preferred and / or optional features of each aspect of the invention / disclosure may be used, alone or in appropriate combination, in the other aspects of the invention / disclosure. The claimed invention is specified in the independent claims of this application. Advantageous adaptations and versions of the claimed invention are specified in the independent claims.

[0071] Description of the drawings

[0072] Following drawings are appended to facilitate the understanding of the claimed invention:

[0073] Fig. 1 A shows a first example of a first embodiment of a pressure compensated electronics module 1 according to the invention comprising a compensation device which comprises a liquid reservoir formed by a total liquid volume in a first compensation chamber and a second compensation chamber, the first and second compensation chambers being arranged in series connection, and the first compensation chamber comprises a first movable pressure compensation part and the second compensation chamber comprises a second movable pressure compensation part, the pressure compensated electronics module being in an initial state in that a first chamber is liquid- filled and a second chamber is gas-filled;

[0074] Fig. IB shows the situation after liquid has leaked from the first chamber into the second chamber, the second movable pressure compensation part has ruptured, and a level of the liquid in the first compensation chamber has dropped relative to the initial state shown in Fig. 1 A;

[0075] Fig. 1C shows a second example of a first embodiment of a pressure compensated electronics module 1 according to the invention comprising a compensation device which comprises a liquid reservoir formed by a total liquid volume in a first compensation chamber and a second compensation chamber, a bypass line bypassing the second movable pressure compensation part features an element in the form of a relief valve in a closed state, and wherein the first and second compensation chambers being arranged in series connection, and the first compensation chamber comprises a first movable pressure compensation part and the second compensation chamber comprises a second movable pressure compensation part, the pressure compensated electronics module being in an initial state in that a first chamber is liquid-filled and a second chamber is gas-filled;

[0076] Fig. ID shows the situation after liquid has leaked from the first chamber into the second chamber, the relief valve in the bypass line is in an open state, and a level of the liquid in the first compensation chamber has dropped relative to the initial state shown in Fig. 1C;

[0077] Fig. 2A shows a third example of the first embodiment of Figs. 1A and IB also with the pressure compensated electronics module in an initial state, however in Fig. 2A there is, in addition to the liquid-filled first chamber and the gas-filled second chamber of Fig. 1 A, a gas-filled third chamber; Fig. 2B shows the situation after liquid has leaked from the first chamber into the third chamber, the second movable pressure compensation part has ruptured, and a level of the liquid in the first compensation chamber has dropped relative to the initial state shown in Fig. 2A;

[0078] Fig. 3A shows a second embodiment of a pressure compensated electronics module according to the invention comprising a compensation device which comprises a liquid reservoir formed by a total liquid volume in one compensation chamber, the one compensation chamber comprising a first movable pressure compensation part and a second movable pressure compensation part, where the pressure compensated electronics module being in an initial state;

[0079] Fig. 3B shows the situation after liquid has leaked from a first chamber into a second chamber, the second movable pressure compensation part has ruptured, and a level of the liquid in the one pressure compensation chamber has dropped relative to the initial state shown in Fig. 3A;

[0080] It should be understood, however, that the drawings are not intended to limit the claimed invention to the subject-matter depicted in the drawings.

[0081] In the drawings, like reference numerals have been used to indicate common parts, elements or features unless otherwise explicitly stated or implicitly understood by the context.

[0082] Detailed description

[0083] In the following, one or more specific embodiments of the invention will be described in more detail with reference to the drawings. However, it is specifically intended that the invention is not limited to the embodiments and illustrations contained herein but includes modified forms of the embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementationspecific decisions must be made to achieve the developer’s specific goals, such as compliance with system and / or business-related constraints, which may vary from one implementation of the invention to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication and manufacture for the skilled person having the benefit of this disclosure.

[0084] First embodiment of pressure compensated electronics module, first example Figs. 1A- 1B

[0085] Fig. 1 A shows a first example of a first embodiment of a pressure compensated electronics module 1 according to the invention comprising a compensation device 600 which comprises a liquid reservoir 410,420,406,404,402 formed by a total liquid volume in a first compensation chamber 320 and a second compensation chamber 220, the first and second compensation chambers 320,220 being arranged in series connection, and the first compensation chamber 320 comprises a first movable pressure compensation part 310 and the second compensation chamber 220 comprises a second movable pressure compensation part 210, the pressure compensated electronics module 1 being in an initial state in that a first chamber 100 is liquid- filled 400 and a second chamber 112 is gas- filled 113.

[0086] Fig. IB shows the situation after liquid has leaked from the first chamber 100 into the second chamber 112, the second movable pressure compensation part 210 has ruptured, and a level of the liquid 406 in the first compensation chamber 320 has dropped relative to the initial state shown in Fig. 1 A.

[0087] Referring to Figs. 1 A and IB, the pressure compensated electronics module 1 comprises a first chamber 100 filled with a liquid 400. The liquid 400 in the first chamber 100 is in fluid communication with the liquid in the compensation device 600 via a first pipe 410. The compensation device 600 comprises a first compensation chamber 320 and a second compensation chamber 220. The first compensation chamber 320 and the second compensation chamber 220 are arranged in a series connection via a second pipe 420.

[0088] The pressure compensated electronics module 1 comprises a second chamber 112 which accommodates a first set of electronics 110 at a predefined pressure. The volume of the second chamber 112 is filled with gas 113. The gas can be at any pressure but is typically a dry gas (such a dry nitrogen gas) at 1 atm protecting the first set of electronics 110 from high pressures and any liquid interaction. If the first set of electronics 110 come into contact with liquid such as oil, water etc. it may eventually malfunction. Thus, the first set of electronics 110 is sensitive to high pressure.

[0089] The second chamber 112 may share a dividing wall 501 with the first chamber 100. The dividing wall 501 can be a penetrator plate with electric lead-throughs interconnecting the first set of electronics 110 and a second set of electronics 401 accommodated in the first chamber 100. The second chamber 112 is preferably protected by a steel housing on all sides except the side where the dividing wall 501 is arranged. Although the second chamber 112 is preferably protected from communication with external pressure and fluid, i.e. it is hermetically sealed, leakage into the second chamber 112 may occur through the penetrator plate. I.e. the penetrator plate renders the dividing wall 501 more prone to leaks than other parts of the second chamber 112.

[0090] As mentioned above, the liquid 400 in the first chamber 100 is in fluid communication with the liquid in the compensation device 600 via the first pipe 410. The compensation device 600 features the first pipe 410 which connects the liquid 400 in the first chamber 100 with a liquid 402 in the second compensation chamber 220. The second compensation chamber 220 holds liquid 402,404 separated by the second movable pressure compensation part 210. Preferably, the same liquid 402,404 is arranged on both sides of the second movable pressure compensation part 210. The second movable pressure compensation part 210 can be a burst disk which can break at a predefined differential pressure difference. Alternatively, it can be a bladder or similar which can rupture when forced against a sharp edge. For example, there may be a sharp edge somewhere in the compensation device which assists in rupturing the second movable pressure compensation part 210. Upon leakage from the first chamber 100 into the second chamber 112, the second movable pressure compensation part 210 is configured to break or rupture such that the liquid 404, and possibly some of liquid 406, flows into the first chamber 100 to replace the liquid which has exited the first chamber 100 into the second chamber 112.

[0091] The liquid level in the first compensation chamber 320 is illustrated by the relative position of the first movable pressure compensation part 310 inside the first compensation chamber 320. The first movable pressure compensation part 310 is preferably a movable physical barrier in the form of a piston, bladder, bellows, membrane etc. separating the liquid 406 (e.g. oil) in the lower part of the first compensation chamber 320 and the ambient fluid 330 (e.g. air or water / seawater) in the upper part of the first compensation chamber 320.

[0092] As is seen in Fig. 1 A, the first compensation chamber 320 holds both liquid 406 and ambient fluid 330.

[0093] If the ambient pressure and / or temperature 10 increases, the compensation device 600 will compensate by allowing a sub-volume of liquid to flow from the second compensation chamber 220 into the first chamber 100, thereby ensuring that the pressure of the liquid 400 in the first chamber 100 is equal to the ambient pressure. When liquid 402 flows into the first chamber 100, the first movable pressure compensation part 310 will move downwards in the first compensation chamber 320 over a distance corresponding to the amount of liquid exiting the second compensation chamber 220.

[0094] Similarly, if the ambient pressure and / or temperature 10 decreases, the compensation device 600 will compensate by allowing a sub-volume of liquid to flow from the first chamber 100 into the second compensation chamber 220, thereby ensuring that the pressure of the liquid 400 in the first chamber 100 is equal to the ambient pressure. If liquid 400 flows out from the first chamber 100, the first movable pressure compensation part 310 will move upwards in the first compensation chamber 320 over a distance corresponding to the amount of liquid exiting the first chamber 100. The required calculations to determine a volume of liquid in the sub-volume is based e.g. on expected differences in ambient pressure and / or temperature, dimensions of the components of the pressure compensated electronics module, and is an exercise which is within the routine work of a person skilled in the art. A total liquid volume in the first pipe 410, the second pipe 420, the liquid volumes

[0095] 406.404.402 in the first compensation chamber 320 and the second compensation chamber 220 make up the volume of the liquid in the liquid reservoir 410,420,406,404,402. Said volume of the liquid in the liquid reservoir

[0096] 410.420.406.404.402 is at least the sum of the volume of the second chamber 112 and said sub-volume. As such, even though there is a leak of liquid 400 from the first chamber 100 into the second chamber 112, the pressure compensated electronics module 1 is still able to carry out its compensation function.

[0097] The relative change in position of the first movable pressure compensation part 310 inside the first compensation chamber 320 when comparing the position of the first movable pressure compensation part 310 in Figs. 1A and IB, equals the volume of the second and / or third chamber 112,122.

[0098] First embodiment of pressure compensated electronics module, second example Figs. 1C-1D

[0099] Fig. 1C shows a second example of a first embodiment of a pressure compensated electronics module 1 according to the invention comprising a compensation device 600 which comprises a liquid reservoir formed by a total liquid volume in a first compensation chamber 320 and a second compensation chamber 220. A bypass line 440’, 440” bypassing the second movable pressure compensation part 210. For illustratable purposes, an element 450 in the form of a relief valve in a closed state is arranged in the bypass line 440 ’,440”. It shall be understood that other forms of element 450 can be used, such as a bellows, a rupture element, a burst disk, or similar. The first and second compensation chambers 320,220 being arranged in series connection. The first compensation chamber 320 comprises a first movable pressure compensation part 310 and the second compensation chamber 220 comprises a second movable pressure compensation part 210. In fig. 1C the pressure compensated electronics module being in an initial state in that a first chamber 100 is liquid-filled and a second chamber 112 is gas-filled 113.

[0100] Fig. ID shows the situation after liquid has leaked from the first chamber 100 into the second chamber 112, the relief valve 450 is in an open state, and a level of the liquid 406 in the first compensation chamber 320 has dropped relative to the initial state shown in Fig. 1C.

[0101] Upon leakage from the first chamber 100 into the second chamber 112, the element 450 is configured to relief pressure such that the liquid 404, and possibly some of liquid 406, flows into the first chamber 100 to replace the liquid which has exited the first chamber 100 into the second chamber 112.

[0102] Alternatively, the functioning of the element 450 may be similar to the first example of the first embodiment described in relation to Figs. 1 A and IB, i.e. the bladder or membrane in the element 450 may be configured to rupture or break at a predefined differential pressure difference. Alternatively, the bladder or membrane can rupture when forced against a sharp edge. For example, there may be a sharp edge somewhere in the element 450 which assists in rupturing the bladder or membrane.

[0103] First embodiment of pressure compensated electronics module, third example Figs. 2A- 2B

[0104] Fig. 2A shows a third example of the first embodiment of Figs. 1A and IB also with the pressure compensated electronics module 1 in an initial state, the pressure compensated electronics module 1 comprising a compensation device 600 which comprises a liquid reservoir 410,420,406,404,402 formed by a total liquid volume in a first compensation chamber 320 and a second compensation chamber 220, the first and second compensation chambers 320,220 being arranged in series connection, and the first compensation chamber 320 comprises a first movable pressure compensation part 310 and the second compensation chamber 220 comprises a second movable pressure compensation part 210, the pressure compensated electronics module 1 being in an initial state in that a first chamber 100 is liquid- filled 400 and a second chamber is gas-filled 112. However, in Fig. 2A there is, in addition to the liquid-filled first chamber 100 and the gas-filled second chamber 112 of Fig. 1 A, a gas-filled third chamber 122.

[0105] Fig. 2B shows the situation after liquid has leaked from the first chamber 100 into the third chamber 122, the second movable pressure compensation part 210 part has ruptured, and a level of the liquid 406 in the first compensation chamber 320 has dropped relative to the initial state shown in Fig. 2A.

[0106] Referring to Figs. 2A and 2B, the pressure compensated electronics module 1 comprises a first chamber 100 filled with a liquid 400. The liquid 400 in the first chamber 100 is in fluid communication with the liquid in the compensation device 600 via a first pipe 410. The compensation device 600 comprises a first compensation chamber 320 and a second compensation chamber 220. The first compensation chamber 320 and the second compensation chamber 220 are arranged in a series connection via a second pipe 420.

[0107] The pressure compensated electronics module 1 comprises a second chamber 112 which accommodates a first set of electronics 110 at a predefined pressure. The volume of the second chamber 112 is filled with gas 113. The gas can be at any pressure but is typically a dry gas (such a dry nitrogen gas) at 1 atm protecting the first set of electronics 110 from high pressures and any liquid interaction. If the first set of electronics 110 come into contact with liquid such as oil, water etc. it may eventually malfunction. Thus, the first set of electronics 110 is sensitive to high pressure.

[0108] The second chamber 112 may share a dividing wall 501 with the first chamber 100. The dividing wall 501 can be a penetrator plate with electric lead-throughs interconnecting the first set of electronics 110 and a second set of electronics 401 accommodated in the first chamber 100. The second chamber 112 is preferably protected by a steel housing on all sides except the side where the dividing wall 501 is arranged. Although the second chamber 112 is preferably protected from communication with external pressure and fluid, i.e. it is hermetically sealed, leakage into the second chamber 112 may occur through the penetrator plate. I.e. the penetrator plate renders the dividing wall 501 more prone to leaks than other parts of the second chamber 112.

[0109] The pressure compensated electronics module 1 comprises a third chamber 122 which accommodates a first set of electronics 120 at a predefined pressure. The first set of electronics 120 in the third chamber 122 may be identical or different to the first set of electronics 110 in the second chamber 112. The volume of the third chamber 122 is filled with gas 123. The gas can be at any pressure but is typically a dry gas (such a dry nitrogen gas) at 1 atm protecting the first set of electronics 120 from high pressures and any liquid interaction. If the first set of electronics 120 comes into contact with liquid such as oil, water etc. it may eventually malfunction. Thus, the first set of electronics 120 is sensitive to high pressure.

[0110] The third chamber 122 may share a dividing wall 502 with the first chamber 100. The dividing wall 502 can be a penetrator plate with electric lead-throughs interconnecting the first set of electronics 120 and the second set of electronics 401 accommodated in the first chamber 100. The third chamber 122 is preferably protected by a steel housing on all sides except the side where the dividing wall 502 is arranged. Although the third chamber 122 is preferably protected from communication with external pressure and fluid, i.e. it is hermetically sealed, leakage into the third chamber 122 may occur through the penetrator plate. I.e. the penetrator plate renders the dividing wall 502 more prone to leaks than other parts of the third chamber 122.

[0111] Preferably, the second chamber 112 and the third chamber 122 are identical and the set of electronics 110 in the second chamber 112 is preferably identical to the set of electronics 120 in the third chamber 122. I.e. the set of electronics 110,120 in the second chamber 112 and in the third chamber 122 are redundant copies such that if one of the set of electronics 110,120 malfunctions, the other set of electronics 120,110 is configured to perform the same function.

[0112] As mentioned above, the liquid 400 in the first chamber 100 is in fluid communication with the liquid in the compensation device 600 via the first pipe 410. The compensation device 600 features the first pipe 410 which connects the liquid 400 in the first chamber 100 with a liquid 402 in the second compensation chamber 220. The second compensation chamber 220 holds liquid 402,404 separated by the second movable pressure compensation part 210. Preferably, the same liquid 402,404 is arranged on both sides of the second movable pressure compensation part 210. The second movable pressure compensation part 210 can be a burst disk which can break at a predefined differential pressure difference. Alternatively, it can be a bladder or similar which can rupture when forced against a sharp edge. For example, there may be a sharp edge somewhere in the compensation device which assists in rupturing the second movable pressure compensation part. Upon leakage from the first chamber 100 into the second chamber 112 (or the third chamber 122), the second movable pressure compensation part 210 is configured to break or rupture such that the liquid 404, and possibly some of liquid 406, flows into the first chamber 100 to replace the liquid which has exited the first chamber 100 into the second chamber 112 (or the third chamber 122).

[0113] The liquid level in the first compensation chamber 320 is illustrated by the relative position of first movable pressure compensation part 310 inside the first compensation chamber 320. The first movable pressure compensation part 310 is preferably a movable physical barrier in the form of a piston, bladder, bellows, membrane etc. separating the liquid 406 (e.g. oil) in the lower part of the first compensation chamber 320 and the ambient fluid 330 (e.g. air or water / seawater) in the upper part of the first compensation chamber 320.

[0114] As is seen in Fig. 2A, the first compensation chamber 320 holds both liquid 406 and ambient fluid 330.

[0115] If the ambient pressure and / or temperature 10 increases, the compensation device 600 will compensate by allowing a sub-volume of liquid to flow from the second compensation chamber 220 into the first chamber 100, thereby ensuring that the pressure of the liquid 400 in the first chamber 100 is equal to the ambient pressure. When liquid 402 flows into the first chamber 100, the first movable pressure compensation part 310 will move downwards in the first compensation chamber 320 over a distance corresponding to the amount of liquid exiting the second compensation chamber 220.

[0116] Similarly, if the ambient pressure and / or temperature 10 decreases, the compensation device 600 will compensate by allowing a sub-volume of liquid to flow from the first chamber 100 into the second compensation chamber 220, thereby ensuring that the pressure of the liquid 400 in the first chamber 100 is equal to the ambient pressure. If liquid 400 flows out from the first chamber 100, the first movable pressure compensation part 310 will move upwards in the first compensation chamber 320 over a distance corresponding to the amount of liquid exiting the second compensation chamber 220. The required calculations to determine a volume of liquid in the sub-volume is based e.g. on expected differences in ambient pressure and / or temperature, dimensions of the components of the pressure compensated electronics module, and is an exercise which is within the routine work of a person skilled in the art.

[0117] A total liquid volume in the first pipe 410, the second pipe 420, the liquid volumes

[0118] 406.404.402 in the first compensation chamber 320 and the second compensation chamber 220 make up the volume of the liquid in the liquid reservoir 410,420,406,404,402. Said volume of the liquid in the liquid reservoir

[0119] 410.420.406.404.402 is at least the sum of the volume of the largest of the second chamber 112 and third chamber 122 and said sub-volume. As such, even though there is a leak of liquid 400 from the first chamber 100 into the largest of the second chamber 112 and the third chamber 122, the pressure compensated electronics module 1 is still able to carry out its function using the respective first or third set of electronics 110,120 in the second chamber 112 or the third chamber 122 which has not had a leakage.

[0120] The relative change in position of the first movable pressure compensation part 310 inside the first compensation chamber 320 when comparing the position of the first movable pressure compensation part 310 in Figs. 2A and 2B, equals the volume of the second and / or third chamber 112,122.

[0121] Second embodiment of pressure compensated electronics module, Figs. 3A-3B

[0122] Fig. 3A shows a second embodiment of a pressure compensated electronics module 1 according to the invention comprising a compensation device 600 which comprises a liquid reservoir 408,409,410 formed by a total liquid volume in one compensation chamber 320, the one compensation chamber 320 comprising a first movable pressure compensation part 310 and a second movable pressure compensation part 210, where the pressure compensated electronics module 1 is in an initial state.

[0123] Fig. 3B shows the situation after liquid has leaked from a first chamber 100 into a second chamber 112 (or third chamber 122), the second movable pressure compensation part 210 has ruptured, and a level of the liquid 409 in the one pressure compensation chamber 320 has dropped relative to the initial state shown in Fig. 3 A.

[0124] Although not disclosed in Figs. 3A and 3B, the pressure compensated electronics module 1 in Figs. 3A and 3B comprises a first chamber 100 and a second chamber 112 (and possibly a third chamber 122) as described in relation to Figs. 1 A-1B and 2A-2B above.

[0125] Referring to Fig. 3A, compensation device 600 consists of one compensation chamber 320 only. The first movable pressure compensation part 310 separates the liquid 409,408 and the ambient fluid 330. The liquid level in the one compensation chamber 320 is illustrated by the relative position of first movable pressure compensation part 310 inside the first compensation chamber 320. The first movable pressure compensation part 310 is preferably a movable physical barrier in the form of a piston, bladder, bellows, membrane etc. separating the liquid 409,408 (e.g. oil) in the lower part of the first compensation chamber 320 and the ambient fluid 330 (e.g. air or water / seawater) in the upper part of the first compensation chamber 320. As is seen in Fig. 3A, the first compensation chamber 320 holds both liquid 409,408 and ambient fluid 330.

[0126] The liquids 408,409 in the one compensation chamber 320 is separated by the second movable pressure compensation part 210. The liquid reservoir is formed by the liquid in the first pipe 410, the liquid 408 below the second movable pressure compensation part 210 and the liquid 409 above the second movable pressure compensation part 210. Preferably, the same liquid 408,409 is arranged on both sides of the second movable pressure compensation part 210. The second movable pressure compensation part 210 can be a burst disk which can break at a predefined differential pressure difference. Alternatively, it can be a bladder or similar which can rupture when forced against a sharp edge. For example, there may be a sharp edge somewhere in the compensation device which assists in rupturing the second movable pressure compensation part.

[0127] When there is a leakage of liquid from the first chamber 100 (not shown in Fig. 3B, see e.g. Fig. IB or 2B) into the second chamber 112 (or third chamber 122), the second movable pressure compensation part 210 ruptures, and a level of the liquid 409 in the one pressure compensation chamber 320 has dropped relative to the initial state shown in Fig. 3 A. This change in level of the liquid 409 is shown in Fig. 3B. Upon leakage from the first chamber 100 into the second chamber 112 (or the third chamber 122), the second movable pressure compensation part 210 is configured to break or rupture and the liquid 404, and possibly some of liquid 409, flows into the first chamber 100 to replace the liquid which has exited the first chamber 100 into the second chamber 112 (or the third chamber 122).

[0128] If the ambient pressure and / or temperature 10 increases, the compensation device 600 will compensate by allowing a sub-volume of liquid to flow from the one compensation chamber 320 into the first chamber 100, thereby ensuring that the pressure of the liquid 400 in the first chamber 100 is equal to the ambient pressure. When liquid 408 flows into the first chamber 100, the first movable pressure compensation part 310 will move downwards in the one compensation chamber 320 over a distance corresponding to the amount of liquid exiting the one compensation chamber 320.

[0129] Similarly, if the ambient pressure and / or temperature 10 decreases, the compensation device 600 will compensate by allowing a sub-volume of liquid to flow from the first chamber 100 into one compensation chamber 320, thereby ensuring that the pressure of the liquid 400 in the first chamber 100 is equal to the ambient pressure. If liquid 400 flows out from the first chamber 100, the first movable pressure compensation part 310 will move upwards in the one compensation chamber 320 over a distance corresponding to the amount of liquid exiting the first chamber 100. The required calculations to determine a volume of liquid in the sub-volume is based e.g. on expected differences in ambient pressure and / or temperature, dimensions of the components of the pressure compensated electronics module, and is an exercise which is within the routine work of a person skilled in the art.

[0130] If there is a second chamber 112 (and not a third chamber 122), the volume of the liquid in the liquid reservoir 408,409,410 is at least the sum of the volume of the second chamber 112 and said sub-volume. As such, even though there is a leak of liquid 400 from the first chamber 100 into the second chamber 112, the pressure compensated electronics module 1 is still able to carry out its compensation function.

[0131] If there is a second chamber 112 and a third chamber 122, the volume of the liquid in the liquid reservoir 408,409,410 is at least the sum of the volume of the largest of the second chamber 112 and third chamber 122 and said sub-volume. As such, even though there is a leak of liquid 400 from the first chamber 100 into the largest of the second chamber 112 and the third chamber 122, the pressure compensated electronics module 1 is still able to carry out its function using the respective first or third set of electronics 110,120 in the second chamber 112 or the third chamber 122 which has not had a leakage.

[0132] The relative change in position of the first movable pressure compensation part 310 inside the first compensation chamber 320 when comparing the position of the first movable pressure compensation part 310 in Figs. 3 A and 3B, equals the volume of the second and / or third chamber 112,122.

[0133] In the preceding description, various aspects of the apparatus according to the invention have been described with reference to the illustrative embodiment. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the apparatus and its workings. However, this description is not intended to be construed in a limiting sense. For example, the reasons for having two movable pressure compensation parts 310,210 is due to regulatory requirements when liquid or fluid forms the barrier subsea. Then it is normally a requirement to have two barriers. The two barriers are then the first and second movable pressure compensation parts. When the second movable pressure compensation part 210 damages or breaks, it opens up the barrier it represents, however, the first movable pressure compensation part 310 is still in place and forms the barrier. Therefore, in principle, if the regulatory requirements were different, it could be possible to design the pressure compensated electronics module 1 with one movable pressure compensation part 310,210 only.

[0134] Various modifications and variations of the illustrative embodiment, as well as other embodiments of the apparatus, which are apparent to person skilled in the art to which the disclosed subject-matter pertains, are deemed to lie within the scope of the present invention as defined by the following claims.

[0135] LIST OF REFERENCE NUMBERS

Claims

Claims1. A pressure compensated electronics module (1) for subsea application, the module (1) being configured to compensate for variations in ambient pressure and / or temperature (10), the module (1) comprising: a liquid- filled, first chamber (100); a gas-filled second chamber (112) accommodating a first set of electronics (110) at a predefined pressure, the second chamber (112) sharing a dividing wall (501) with the first chamber (100); a compensation device (600) comprising a liquid reservoir being in fluid communication with the first chamber (100) and being in pressure communication with ambient pressure (10,330) allowing a sub-volume of the liquid in the liquid reservoir to flow into and out of the first chamber (100) to allow the liquid inside the first chamber (100) to adopt to ambient pressure and / or temperature; wherein the volume of the liquid reservoir is at least the sum of the volume of the second chamber (112) and said sub-volume.

2. The module (1) according to claim 1, wherein said predefined pressure is atmospheric pressure.

3. The module (1) according to any of the preceding claims, wherein the liquid reservoir (410,420,406,404,402; 408,409,410;410,420) is in pressure communication with an ambient fluid via a first movable pressure compensation part (310) exposed to ambient pressure (10,330) on one side and the pressure of the liquid inside the first chamber (100) on the other side.

4. The module (1) according to claim 3, wherein the first movable pressure compensation part (310) is a bladder, bellows, a piston or a membrane.

5. The module (1) according to any of the preceding claims, wherein the liquid in the first chamber (100) and the liquid in the liquid reservoir (410,420,406,404,402; 408,409,410;410,420) is the same liquid.

6. The module (1) according to any of the preceding claims, wherein the first chamber (100) accommodates a second set of electronics (401).

7. The module (1) according to any of the preceding claims, wherein the module comprises a gas-filled third chamber (122) accommodating a third set ofelectronics (120) at a predefined pressure, the third chamber (122) sharing a dividing wall (502) with the first chamber (100).

8. The module (1) according to claim 7, wherein the second and the third chamber (112, 122) have the same volume.

9. The module (1) according to claim 7 or 8, wherein the first set of electronics in the second chamber (112) and the third set of electronics (120) in the third chamber (122) are redundant copies.

10. The module (1) according to claim 3, or any one of claims 4-9 when dependent upon claim 3, wherein the module (1) comprises a second movable pressure compensation part (210) arranged inside the liquid reservoir, wherein the first movable pressure compensation part (310) and the second movable pressure compensation part (210) are arranged in series connection.

11. The module (1) according to claim 10, wherein the compensation device (600) comprises:- a first compensation chamber (320) in pressure communication with the ambient fluid via the first movable pressure compensation part (310), the first compensation chamber (320) is configured to hold a fraction of the liquid of the liquid reservoir at least equal to the sum of the volume of the second chamber (112, 122) and said sub-volume, and- a second compensation chamber (220) arranged in series connection between the first chamber (100) and the first compensation chamber (320).

12. The module (1) according to claim 11, wherein the second compensation chamber (220) is completely liquid-filled.

13. The module (1) according to claim 11 or 12, wherein a volume of the second compensation chamber (220) is divided in two by the second movable pressure compensation part (210).

14. The module (1) according to any one of claims 11-13, wherein the second compensation chamber (220) is configured to hold a fraction of the liquid reservoir at least equal to the sub-volume.

15. The module (1) according to any one of claims 11-14, wherein the second compensation chamber (220) is configured to hold a fraction of the liquid reservoir at least equal to the second chamber (112).

16. The module (1) according to any one of claims 10-15, wherein the first or second movable pressure compensation part (310;210) is configured to be damaged or break.

17. The module (1) according to any one of claims 10-16, wherein the module (1) comprises:- a bypass line (440’, 440”) bypassing the second movable pressure compensation part (210);- an element (450) arranged in the bypass line (440’, 440”), and wherein the element (450) is configured to open, be damaged or break.

18. The module (1) according to claim 17, wherein the element (450) comprises a bladder, a bellows, a burst disc, a relief valve, a membrane.

19. The module (1) according to claim 3, or any one of claims 4-10 when dependent upon claim 3, wherein the compensation device (600) comprises:- a first compensation chamber (320) in pressure communication with the ambient fluid via the first movable pressure compensation part (310), the first compensation chamber (320) is configured to hold a fraction of the liquid of the liquid reservoir at least equal to the sum of the volume of the second chamber (112, 122) and said sub-volume.

20. The module according to claim 19, wherein the second movable pressure compensation part (210) is arranged inside the first compensation chamber (320) or in a direct continuation of the first compensation chamber (320).

21. The module (1) according to any of the preceding claims, wherein the dividing wall (501, 502) is a penetrator plate.

22. The module according to any of the preceding claims, wherein the dividing wall (501) comprises electrical lead-throughs.

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