Device for cleaning fuel and use thereof

Abstract

The invention relates to a device (1) for cleaning fuel in a fuel tank (92) of an aircraft (90) and the use thereof. The device has a predetermined flow direction (2) of the fuel and comprises a plurality of units arranged in series such that the fuel flows from one unit to another, these units being:-an extraction unit (10) for extracting the fuel from a fuel tank (92) of an aircraft (90); a filter unit (30) for filtering the drawn fuel; and-a recirculation unit (70) for returning the filtered fuel to the fuel tank (92) of the aircraft (90), the recirculation unit comprising a hose (71) for selectively fluidly connecting the device (1) to the fuel tank (92) of the aircraft (90), in which a pump (80) is provided for delivering fuel at least through the hose (71) of the recirculation unit (70).

Description

[0001] The invention relates to a device for cleaning fuel in a fuel tank of an aircraft and to the use thereof.

[0002] Fuel stored in aircraft tanks may be contaminated. In addition to contaminants introduced into the tank through the openings (e.g., during refueling or maintenance, such as, for example, metal shavings, sealant residues and other production or maintenance debris), bacteria, molds and fungi may also form in the tank, especially when the aircraft is parked for a long time, and said contaminants (at least in the case that they are not firmly attached to the inner surface of the tank) may also lead to contamination of the fuel. At the latest, when microbial contamination of the inner wall of the tank is also treated with toxic biocides known in the prior art, the fuel will be contaminated with biomass (in the form of dead microorganisms). Possible excretions of any remaining live microorganisms may also lead to contamination of the fuel.

[0003] In order to prevent contaminants in the fuel from entering the aircraft's propulsion system, it is known in the art to use fuel filters that can filter out solids larger than a predetermined size from the fuel during operation. A disadvantage of this prior art is that, particularly in the case of heavily contaminated fuel, the fuel filter may become clogged during operation, thereby creating a safety risk.

[0004] If a tank or the fuel contained therein is heavily contaminated, in particular due to microbial contamination, it is known in the art to perform a "tank entry and inspection" through the tank opening to clean the affected tank, in particular to mitigate the risk of filter clogging. This type of tank inspection is complex and can therefore only be performed by specially trained and qualified personnel, and typically takes several days, partly because of the need for preliminary steps such as draining and ventilation, during which the hangar space is usually continuously occupied.

[0005] The object of the present invention is to create a device for cleaning fuel in a fuel tank of an aircraft and its use, in which the disadvantages known from the prior art no longer occur, or occur only to a lesser extent.

[0006] This object is achieved by the device according to the main claim and by the use according to the dependent claims. Advantageous developments are subject matter of the dependent claims.

[0007] The invention therefore relates to a device for cleaning fuel in a fuel tank of an aircraft, the device having a flow direction of the fuel and units for conveying the fuel which are fluidically connected to one another, the device comprising in the flow direction:

[0008] - extraction unit for extracting fuel from the aircraft's tanks;

[0009] - a filter unit for filtering the extracted fuel; and

[0010] a recirculation unit for returning the filtered fuel to the aircraft's tank, the recirculation unit comprising a hose for selectively connecting the device fluidically to the aircraft's tank,

[0011] Therein, a pump is provided for moving the fuel at least through the hose of the recirculation unit.

[0012] The invention furthermore relates to the use of the device according to the invention, wherein the extraction unit (10) and the recirculation unit (70) are connected to the same aircraft fuel tank.

[0013] First, several terms used in connection with the present invention will be explained.

[0014] The "specified flow direction" through the device is the direction in which the liquid (in this case the fuel) predominantly flows through the various units of the device during proper use. In this case, the flow direction does not provide information about the actual flow direction of the liquid within the device, but is only used to identify the order in which the various units are traversed. It is also not excluded that the liquid may remain stationary in certain areas and / or during certain periods, or even flow against the specified flow direction.

[0015] Two cells are "fluidically connected" when they are connected to each other in a manner such that liquid can flow from one cell to the other (particularly along a specified flow direction).

[0016] The device according to the invention uses a cyclic process to filter out solid particles that may be present in the fuel, so that the fuel in the fuel tank of an aircraft stationary on the ground can be cleaned efficiently with minimal effort, thereby reducing the load on the aircraft fuel filter during operation: if at least a part (preferably a large part) of the solids in the fuel have been removed by the device according to the invention, the aircraft's fuel filter has fewer particles to filter during operation. This increases the reliability of the fuel filter and therefore increases the fuel supply of the aircraft during operation. In addition, the early removal of fuel contaminants helps to prevent contamination of the inner surface of the tank, thereby reducing the risk of damage to the aircraft, such as corrosion caused or accelerated by contamination.

[0017] In this case, the device according to the invention comprises at least the following components, which are arranged in the order in which they are traversed in the prescribed flow direction: at least one extraction unit, a filter unit, and a recirculation unit, wherein each of these units is fluidically connected to one another. Fuel is sucked from the aircraft tank into the device according to the invention via the extraction unit and then passes through the filter unit, wherein the fuel is filtered by removing solid particles larger than a certain size. The filtered fuel is then returned via the recirculation unit and the hose to the aircraft tank from which it was originally extracted. In this case, the device also comprises a pump, which causes the filtered fuel to be pumped back into the aircraft tank.

[0018] In this case, the pump may be part of the recirculation unit. The flow through a unit located upstream of the recirculation unit, such as a filter unit, may be facilitated in flow direction by gravity in this case, by an additional pumping device, or by the extraction action of a pump in the recirculation unit.

[0019] Alternatively, the pump can be positioned at a different point within the device, for example upstream of the filter unit in the flow direction. In an arrangement of this type, it must simply be ensured that the pump also delivers fuel through the hose of the recirculation unit.

[0020] The cleaning of the fuel can be carried out continuously by means of suitably configured devices during an immediate circulation process, which means that the fuel extracted via the extraction unit is immediately returned to the tank via the recirculation unit after passing through the filter unit or device. However, it is also possible to include an intermediate storage unit between the filter unit and the recirculation unit, so that the filtered fuel can be temporarily stored before being returned to the tank. This type of intermediate storage allows the recirculation of the fuel to be delayed relative to its extraction, thereby reducing the mixing of unextracted, unfiltered fuel with the filtered, returned fuel in the aircraft tank. With a sufficiently large intermediate storage unit, it is even possible to postpone the recirculation until all the fuel has been extracted from the aircraft tank, thereby completely eliminating the above-mentioned mixing.

[0021] The intermediate storage unit may directly comprise an intermediate storage element, for example in the form of a tank. However, it is preferred that the intermediate storage unit comprises a connection module for connecting an external intermediate storage tank, such as a tank of a fuel truck. By not incorporating the tank directly into the intermediate storage unit, the unit and the entire device can be made smaller and easier to manage. The connection module that connects the external intermediate storage tank to the intermediate storage unit is only required when a specific cleaning operation specifically requires an intermediate storage tank. The intermediate storage module may also have both its own intermediate storage tank and a connection module. In this configuration, additional external tanks can be attached via the connection module as needed to expand the storage capacity. The connection module may include at least one connection point for attaching an external intermediate storage tank thereto, and it may also include a pump for moving fuel into and / or out of the intermediate storage tank.

[0022] The extraction unit is preferably connected to the aircraft tank independently and separately from the recirculation unit, as will be explained in more detail below. However, in particular, for example in the case of an aircraft tank having only one or at least only one easily accessible tank opening, it is also possible to use the hose of the recirculation unit to extract fuel from the tank. In this case, a switching module can be provided so that the hose of the recirculation unit can be selectively fluidically connected to the extraction unit and to the recirculation unit. Thus, the hose can be used for extraction and recirculation of fuel as required. Since extraction and recirculation cannot take place simultaneously in this case, the intermediate storage unit will generally have to be provided with this variant.

[0023] Alternatively, instead of sharing the hose of the recirculation unit, the extraction unit may include at least one hose fluidically connected thereto for coupling with a fuel discharge opening and / or another opening of the aircraft tank. "Fuel discharge opening" refers to an opening on the tank that is located at or near the lowest point of the tank when the aircraft is parked on a flat surface, so that fuel can flow out by gravity when the fuel discharge opening is opened. In order to connect the hose of the extraction unit, a funnel may be provided at its free end to collect the fuel discharged from the fuel discharge opening. However, in order to reduce the risk of fire, it is preferred to provide a hose coupling at the free end of the extraction unit hose, which hose coupling can produce a sealed connection with the opening in the tank.

[0024] As mentioned above, the fuel can be extracted from the aircraft tank by gravity alone. However, the extraction unit can also be designed for suction-based fuel extraction using at least one hose fluidically connected to the extraction unit. This type of suction mechanism can support gravity-based fuel extraction where feasible, or also enable fuel extraction through tank openings that cannot be extracted based on gravity. In this case, the hose can be equipped with a hose coupling at its free end for secure connection to the opening of the aircraft tank, or the hose is designed as a suction hose for opening the aircraft tank. By using the suction action, the fuel flow rate through the at least one hose can be accurately controlled. In this case, the preferred flow rate range is from 0.3m / s to 7m / s, preferably from 2m / s to 3m / s.

[0025] The extraction may be achieved solely by the suction action of a pump arranged to move the fuel through the hose of the recirculation unit. Alternatively, the extraction unit may comprise a separate suction pump.

[0026] Preferably, in the flow direction, the upstream or downstream fluid of the filter unit is connected to a water separation unit to separate water from the extracted fuel. The water separation unit can remove any water present in the fuel, otherwise the water may cause corrosion to the metal components in contact with the fuel. The separation of water and fuel can be achieved using known techniques (such as swirl). Specifically, in this case, it is preferred that the water separation device is externally powered so that the swirl required for water separation does not depend on the fuel flow rate through the water separation device. In addition, the water separation unit can be sensor-controlled so that its operating parameters can be adjusted based on the actual water content in the fuel.

[0027] If it can be assumed that the fuel in the tank and any water present are separated into different phases within the tank and can also be extracted independently of one another, the water separation unit can be configured as a sensor-controlled three-way valve with one inlet and two switchable outlets. When a suitable sensor in the water separation unit detects water entering the valve inlet, the valve can be switched to an outlet which is connected to, for example, a collecting container; if the sensor detects fuel at the valve inlet, the valve can be switched to an outlet which conducts the fuel to a unit arranged downstream of the water separation unit in the flow direction, such as a filter unit.

[0028] The filter unit may comprise one or more filters connected in series. The one or more filters may preferably have a fineness of from 0.2 μm to 15 μm, wherein the fineness of the plurality of filters arranged in series preferably decreases in the direction of flow so that the filtration takes place from coarse to fine. In order to filter out microbial components from the fuel, a filter fineness of 0.2 μm is in principle required. However, depending on the tank volume and the level of contamination, filters with such a fineness may quickly become clogged, making such filters suitable only for a few applications.

[0029] The filter can in principle be made of any material suitable for aviation fuel. The filter can preferably be made of metal in order to ensure a long service life.

[0030] Preferably, the filter unit has one or more sampling points. These sampling points make it possible to extract samples of the fuel flowing through the filter unit so that the fuel can be subjected to laboratory analysis and the functionality of the filter unit or the entire device can be assessed therefrom.

[0031] The filter unit may include a differential pressure measuring device to measure the differential pressure before and after the filter unit or an individual filter therein. This enables detection of blockages in the filter unit or in one of the individual filters. By analyzing the increase in differential pressure relative to the filtered fuel volume, initial conclusions can be drawn about the degree of fuel contamination.

[0032] A UV disinfection unit may be arranged in fluid connection downstream of the filter unit in the flow direction. This type of UV disinfection unit may be used to kill or inactivate microorganisms in the fuel which are not removed by the filter due to their size.

[0033] The device may also include at least one conductivity measuring unit that measures the conductivity of the fuel flowing through the device. For example, a conductivity measurement performed downstream of the filter unit may verify whether the cleaned fuel meets the conductivity standards required for aviation fuel.

[0034] The device may also include an additive mixing unit for mixing additives into the fuel as it flows through the device. For example, an additive for enhancing the electrical conductivity of the fuel, such as a static dissipative additive (SDA), may be added, for example, based on the results of the electrical conductivity measurement. Furthermore, a biocide may be introduced to eliminate microorganisms still present in the tank, and / or an anti-icing agent (Fuel System Icing Inhibitor (FSII) or other anti-icing agent) may be added to prevent the fuel from freezing.

[0035] For this purpose, the hose of the recirculation unit and / or the hose of the extraction unit may have a standard aircraft refueling coupling at its free end, thereby ensuring a simple and secure connection between the device and the aircraft tank. The aircraft refueling coupling may be a standard component and / or coupling customized for a specific aircraft model. In addition, one or more adapters may be provided so that the aircraft refueling coupling at the free end of the recirculation unit hose can be connected to different aircraft models. In particular, the free ends of the hoses of the recirculation unit and / or the extraction unit may preferably be provided with an aircraft refueling coupling that complies with the civil standard SAE AS5887.

[0036] The device may preferably have a central control unit for managing the controllable units or their controllable components, wherein the control unit may also process measured values ​​or similar information related to the cleaning process or the functioning of the individual units. The control unit may be programmable so that it can perform a fuel cleaning operation tailored to a specific aircraft or its tank.

[0037] Preferably, the device can be fully mounted on a frame, making it easy to transport, including, for example, by air. The device can also be mounted directly on a vehicle.

[0038] Furthermore, the device may have its own power source, such as a battery or a generator. Alternatively, the device may be designed for connection to an existing power network, such as a hangar power supply.

[0039] Reference is made to the previous description for clarifying the use according to the invention. In this case, the units of the device used, if present, generally operate as intended. The only exception is the intermediate storage unit, if available. Even if an intermediate storage unit is provided, so that the fuel return is fundamentally decoupled from the fuel extraction, a direct cycle cleaning process can still be achieved with a corresponding device by appropriate control of the individual units and their components to ensure that the intermediate storage unit remains essentially empty.

[0040] Besides this, in the use according to the invention, the extraction of fuel from the aircraft's fuel tank and / or the return of fuel to the aircraft's fuel tank can be carried out continuously or intermittently, depending on the desired cleaning process.

[0041] The invention will now be described using advantageous embodiments by way of example with reference to the accompanying drawings. In the drawings:

[0042] Figure 1 : shows a schematic illustration of the use of a first exemplary embodiment of the device according to the invention;

[0043] Figure 2 : Shows Figure 1 A schematic detailed representation of the device according to the invention shown in ; and

[0044] Figure 3 : shows a schematic detailed representation of a second exemplary embodiment of the device according to the invention.

[0045] Figure 1 The use of a first exemplary embodiment of a device 1 according to the invention is schematically shown, wherein the device Figure 2 , for cleaning the fuel in a fuel tank 92 of an aircraft 90. In this case, the fuel tank 92 is integrated in a wing 91 of the aircraft 90.

[0046] The device 1 is connected to the fuel discharge opening of a tank 92 of an aircraft 90 via a hose 11 which distributes to an extraction unit 10 of the device. For this purpose, the free end of the hose 11 has an adapter for connection to a tank bottom valve located at the lowest point of the tank 92.

[0047] Furthermore, the device 1 is connected via a hose 71 assigned to the recirculation unit 70 to a tank opening conventionally used for refueling an aircraft 90. For this purpose, the free end of the hose 71 has an aircraft refueling connection 72 in accordance with the SAE AS5887 standard.

[0048] The device 1 defines a general flow direction 2 of the fuel, i.e., starting from the tank 92, through the hose 11 of the extraction unit 10, and returning to the tank 92 via the hose 71 of the recirculation unit 70. Along this flow direction 2, the fuel passes through the various units 10, 20, 30, 40, 50, 60, 70 within the device 1, which are fluidly connected in series and are referred to below. Figure 2 Explain in more detail.

[0049] The extraction unit 10 comprises a suction pump 13 which sucks fuel through the hose 11. The suction pump 13 ensures a constant fuel flow of about 1 m / s through the hose 11, regardless of whether the fuel could potentially flow through the hose 11 by gravity alone. Furthermore, the suction pump 13 ensures a constant fuel flow through units downstream of the extraction unit 10.

[0050] A water separation unit 20 is provided after the extraction unit 10. The water separation unit 20 comprises a filter-type water separator, preferably with an automatic drain device 21. The water separation unit 20 may also comprise a sensor (not shown) to detect the water content in the fuel flowing into or out of the filter-type water separator 21.

[0051] The fuel then flows into the filter unit 30. In the exemplary embodiment shown, the filter unit 30 comprises two filters 31, 32 connected in series, wherein the first filter 31 through which the fuel flows in the flow direction 2 has a fineness of 5 μm, while the other filter 32 has a fineness of 1 μm. A filter sampling point 33 is provided between the two filters 31, 32 made of metal, which enables the collection of partially filtered fuel (in particular, the collection of fuel filtered only by the first filter) for laboratory analysis. This type of analysis can determine, for example, whether the fineness ratio of the two filters 31, 32 is appropriately selected to ensure sufficient filtering performance, on the one hand, while avoiding premature clogging of one of the filters 31, 32, and on the other hand ensuring a normal filtering effect. If the first filter 31 is too fine compared to the second filter 32, which mainly determines the overall filtering effect, the first filter 31 may be blocked quickly; if the first filter 32 is too coarse, the second filter 32 may be blocked prematurely. Ideally, the fineness of the filters 31, 32 should be selected so that their clogging speed is approximately the same.

[0052] The filter unit 30 further comprises a differential pressure measuring device 34, which measures the differential pressure before the first filter 31 and after the second filter 32. By monitoring the differential pressure, a potential blockage of one of the two filters 31, 32 can be detected and a warning can be issued, for example, to clean or replace the filters 31, 32. As an alternative to the connector-type differential pressure measuring device 34, a separate differential pressure measuring device can also be provided for each filter 31, 32.

[0053] After the filter unit 30 there is arranged a UV disinfection unit 40 through which the fuel flowing is exposed to UV radiation, in particular to UV-C radiation, along a UV disinfection path 41 in order to kill or inactivate vegetative microorganisms which may still be present in the filtered fuel.

[0054] This is followed by an additive mixing unit 50, which enables the addition of an additive (in this case an additive that enhances conductivity) from a storage tank 52 as required via a controllable valve 51. The amount of additive added is determined using a conductivity measuring unit 53. Based on the conductivity measured for the fuel after passing through the UV disinfection unit 40, the addition of the additive can be precisely controlled via the valve 51.

[0055] After passing through the additive mixing unit 50, the fuel enters the intermediate storage unit 60. The intermediate storage unit 60 comprises an intermediate storage tank 61 for temporarily storing a certain amount of fuel, thereby in principle enabling the extraction and return of the fuel to be decoupled. In the event that the capacity of the intermediate storage tank 61 is insufficient, the intermediate storage tank 60 further comprises a connection module 62, which enables an external tank 95 (such as the tank 95 of a refueling truck 96) to be connected as required (and is therefore only indicated in dashed lines) to a hose 97 (reference Figure 1 ). The connection module 62 comprises pumping means for transferring fuel from the intermediate storage tank 61 into the attached tank 95 and vice versa.

[0056] The fuel stored in the intermediate storage tank 61 of the intermediate storage unit 60, which is to be returned to the tank 92 of the aircraft 90, is pumped back via the recirculation unit 70 and its hose 71. The recirculation unit 70 comprises a suitable pump 80 for this purpose.

[0057] The functional operation of the device 1 follows directly from the above description: the fuel extracted via the extraction unit 10 flows through the various cleaning units: the water separation unit 20, the filter unit 30 and the UV disinfection unit 40, if necessary, additives are added to the fuel in the additive mixing unit 50 to enhance the conductivity, and the cleaned fuel, now having the desired conductivity, is then temporarily stored in the intermediate storage unit 60, or in the intermediate storage tank 61, or in the external tank 95. The fuel is then returned from the intermediate storage tank 60 to the tank 92 of the aircraft 90 by means of the recirculation unit 70, or is pumped back using the pump 80. In this case, depending on the nature of the required cleaning, an immediate return can be performed, which means that the intermediate storage tank 61 remains practically empty and the device 1 performs a cyclic cleaning; however, it is also possible to temporarily store part or even all of the fuel from the tank 92, thereby decoupling the extraction and return processes of the fuel in time.

[0058] A central control unit (not shown) may be provided for managing the controllable components of the individual units 10 to 70 (as described above) and the pump 80, which control unit may also be connected to various sensors etc. in order to control the individual units 10 to 70 and the overall function of the device 1. The control unit may be programmable, so that a cleaning process tailored to a particular aircraft and its tank 92 can be pre-programmed.

[0059] like Figure 1 As depicted in , the device 1 can be arranged on a rolling cart. For power supply, the device 1 is connected to the hangar's electrical grid (not shown).

[0060] exist Figure 3 A second exemplary embodiment of the device 1 according to the invention is depicted in FIG. In this case, the device 1 can be as follows Figure 1 Use as described in , but with Figure 2 Compared to the device 1 shown in FIG. 1 , it only comprises the minimum required units 10 , 30 , 70 .

[0061] In flow direction 2, the device 1 first comprises an extraction unit 10, followed by a pump 80, the fuel flowing through the device flows through a filter unit 30 and then returns via a recirculation unit 70 and its hose 71 to the tank 92 of the aircraft 90 from which the fuel was originally extracted (see Figure 1 ).

[0062] although Figure 3 The filter unit 30 in the device 1 shown in FIG. 1 is structurally similar to Figure 2 The filter unit 30 in the device 1 shown in FIG. 1 is identical and can therefore be referred to as Figure 2 However, the extraction unit 10 and the recirculation unit 70 are designed as purely passive units: the extraction unit 10 does not include a suction pump 13 (see Figure 2 ), the pump 80 is arranged outside the recycling unit 70.

[0063] In order to ensure the flow direction 2 of the device 1 and at least the recirculation of the fuel, a pump 80 is provided which is arranged upstream of the filter unit 30 in the flow direction 2. In this case, the pump 80 is designed to ensure that even with a defined pressure drop across the filters 31, 32 of the filter unit 30, the pump 80 delivers sufficient fuel so that the filtered fuel can be returned via the hose 71. Naturally, the pump 80 is also designed to resist clogging from expected contaminants in the fuel.

[0064] exist Figure 3 In the exemplary embodiment shown in , the extraction of fuel can take place solely due to gravity. However, the pump 80 can also be designed to generate a suction effect through the hose 11 of the extraction unit 10.

[0065] Figure 3 The device 1 shown in FIG. 1 may also comprise a central control unit (not shown) which ensures proper operation of the device 1 .

Claims

1. A device (1) for cleaning fuel in a fuel tank (92) of an aircraft (90), the device having a defined flow direction (2) for the fuel and units for conveying the fuel which are fluidically connected to one another, the device comprising in the flow direction (2): - an extraction unit (10) for extracting fuel from said tank (92) of the aircraft (90); - a filter unit (30) for filtering the extracted fuel; and a recirculation unit (70) for returning the filtered fuel to the fuel tank (92) of the aircraft (90), the recirculation unit comprising a hose (71) for selectively fluidly connecting the device (1) to the fuel tank (92) of the aircraft (90), Therein, a pump (80) is arranged to move the fuel at least through the hose (71) of the recirculation unit (70).

2. The device according to claim 1, It is characterized in that An intermediate storage unit (60) is provided between the filter unit (30) and the recirculation unit (70) so that the fuel can be temporarily stored in an intermediate storage tank (61).

3. The device according to claim 2, It is characterized in that The intermediate storage unit (60) comprises a connection module (62) for connecting to an external intermediate storage tank (95).

4. The device according to claim 2 or 3, It is characterized in that A switching module is provided to enable the hose (71) of the recirculation unit (70) to be selectively fluidically connected to the extraction unit (10).

5. The device according to any one of the preceding claims, It is characterized in that The extraction unit (10) comprises at least one hose (11) fluidically connected to the extraction unit for fluidly coupling with a fuel discharge opening of the tank (92) and / or another tank opening.

6. The device according to any one of the preceding claims, It is characterized in that The extraction unit (10) comprises a suction pump (13) for sucking fuel through at least one hose (11, 71) fluidically connected to the extraction unit (10), by means of which a fuel flow rate of from 0.3 m / s to 7 m / s, preferably from 2 m / s to 3 m / s, through the at least one hose (11, 71) can be generated, preferably in a controlled manner.

7. The device according to any one of the preceding claims, It is characterized in that In the flow direction (2), a water separation unit (20) is fluidically connected upstream or downstream of the filter unit (30) for separating water from the extracted fuel, wherein the water separation unit (20) is preferably externally powered (22) and / or sensor-controlled.

8. The device according to any one of the preceding claims, It is characterized in that The filter unit (30) includes one or more filters (31, 32) having a fineness of 0.2 μm to 15 μm and connected in series and / or made of metal.

9. The device according to any one of the preceding claims, It is characterized in that The filter unit (30) has one or more sampling points (33).

10. The device according to any one of the preceding claims, It is characterized in that The filter unit (30) comprises a differential pressure measuring device (34).

11. The device according to any one of the preceding claims, It is characterized in that A UV disinfection unit (40) is arranged in fluid connection downstream of the filter unit (30) in the flow direction (2).

12. The device according to any one of the preceding claims, It is characterized in that The device (1) comprises at least one conductivity measuring unit (53) which measures the conductivity of the fuel flowing through the device (1).

13. The device according to any one of the preceding claims, It is characterized in that The device (1) comprises an additive mixing unit (50) for mixing an additive into the fuel as the fuel flows through the device (1).

14. Use of a device according to any one of claims 1 to 13 for cleaning fuel in a fuel tank (92) of an aircraft (90), wherein: The extraction unit (10) and the recirculation unit (70) are connected to the same fuel tank (92) of an aircraft (90).

15. The use according to claim 14, It is characterized in that Extracting fuel from the fuel tank (92) of the aircraft (90) and / or returning the fuel to the fuel tank of the aircraft is performed continuously or intermittently.

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