SE541336C2

SE541336C2 - A filter arrangement for a liquid reservoir

Info

Publication number: SE541336C2
Application number: SE1751075A
Authority: SE
Inventors: Esa Rosvall; Mattias Lindfelt
Original assignee: Scania Cv Ab
Priority date: 2017-09-06
Filing date: 2017-09-06
Publication date: 2019-07-09
Also published as: DE102018006911A1; SE1751075A1

Abstract

The invention relates to a filter arrangement (10) for a liquid reservoir (120) with an air inlet (126), the filter arrangement (10) comprising: a container (12); and a tube (14) arranged to lead ambient air into the container (12), wherein the container (12) comprises at least one cleaning liquid (CL). The container (12) is adapted to be arranged in fluid communication with the air inlet (126) of the liquid reservoir (120), such that ambient air is lead through the cleaning liquid (CL) in the container (12) before entering the liquid reservoir (120).The invention also relates to an arrangement (100) for supplying urea comprising such a filter arrangement (10) and a vehicle (1).

Description

A filter arrangement for a liquid reservoir TECHNICAL FIELD The present invention relates to a filter arrangement for a liquid reservoir. The invention also relates to a vehicle comprising such a filter arrangement. More specifically the present invention relates to a liquid based filter for cleaning air in fluid communication with a liquid reservoir.

BACKGROUND Tanks for accommodating liquids of various kinds often have venting openings or venting lines arranged in fluid communication with the ambient air. Depending on the geographical location, the weather and road conditions the ambient air could be more or less polluted/contaminated. Particles in the air are very small but accumulated in a tank these particles could cause problems. The problem with contaminated air may exist for example for tanks in vehicles. Fuel tanks and urea tanks are examples of tanks that comprise venting lines in fluid communication with the ambient air for air intake into the tanks. In certain environments, such as constructions sites, agricultural areas and similar, the air would comprise more particles and the contaminated air could thus enter the venting line and the liquid tank. The liquid in the tank would thereby become contaminated which might lead to pump inlet filters being clogged, which eventually could affect the whole fuel system or exhaust aftertreatment system.

Conventional air filters for such small particles require very small mesh sizes and in environments with high humidity and low air flow such filters may easily be clogged. A frequent need of cleaning or replacing clogged filters may be cumbersome and time consuming and it is therefore desired to achieve an alternative solution to prevent contaminated air from entering liquid tanks.

Document US2015135956 A1 discloses a tank ventilation filter for a vehicle comprising a filter element fluidically arranged between the air inlet and the air outlet. Document US5912368 A discloses an air filter assembly arranged to supply clean and dry purge air to a canister for collecting fuel vapours. The filter assembly comprises a plurality of mating and non-mating baffle sets, the spaces between which gradually decreases, thereby forcing the air to travel an increasingly tortuous path.

SUMMARY OF THE INVENTION Despite known solutions in the field, it would be desirable to develop a filter arrangement for liquid reservoirs which alleviates or at least reduces the drawbacks with prior art.

An object of the present invention is thus to achieve an advantageous filter arrangement for a liquid reservoir, which is suitable for polluted environments in all climates.

Another object of the invention is to achieve an advantageous filter arrangement for a liquid reservoir, which is compact and cost effective.

A further object of the invention is to achieve an advantageous filter arrangement for a liquid reservoir, which is flexible and easier to clean.

The herein mentioned objects are achieved by a filter arrangement for a liquid reservoir and a vehicle comprising such an arrangement according to the independent claims.

Hence, according to an aspect of the present invention a vehicle filter arrangement for a liquid reservoir with an air inlet is provided. The filter arrangement is adapted to be used for a reservoir containing urea or diesel on a vehicle and comprises: a container; and a tube arranged to lead ambient air into the container, wherein the container comprises at least one cleaning liquid. The container is adapted to be arranged in fluid communication with the air inlet of the liquid reservoir, such that ambient air is lead through the at least one cleaning liquid in the container before entering the liquid reservoir.

The filter arrangement may be referred to as a liquid based filter arrangement. The filter arrangement is preferably adapted to be used for liquid reservoirs on vehicles but may be used for any liquid reservoirs having an air inlet. The filter arrangement may thus be referred to as a vehicle filter arrangement. The ambient air is defined as the air in the immediate surroundings of the liquid reservoir. The ambient air may be referred to as the outside air and may comprise impurities/contaminants. The filter arrangement is suitably adapted to be used for a reservoir containing urea or diesel on a vehicle. Such reservoirs comprise air inlets in fluid communication with the ambient air and on vehicles today there are no filter arrangements arranged upstream of these air inlets. Without a filter arrangement the contaminated ambient air enters the liquid reservoir (urea or diesel tank) and in some polluted environments this could result in a large amount of contaminants in the liquid. The contaminants in the liquid could cause problems with for example pumps arranged to pump the urea or diesel from the reservoir. It may thus be desired to clean the air before entering the liquid reservoir. In the case where the reservoirs arranged on a vehicle the amount of contaminants in the ambient air may vary depending on where the vehicle is travelling. In some environments with high humidity and polluted air conventional air filters may be unsuitable as mentioned in the background. With the filter arrangement according to the invention high humidity and/or great contamination is not a problem. By means of the filter arrangement according to the invention, the ambient air is lead into the container via the tube and any particles in the air will be separated from the air and be trapped inside the cleaning liquid. The air supplied into the cleaning liquid will generate bubbles, which will burst at the surface of the cleaning liquid and the filtered clean air is released while the contaminants remain in the cleaning liquid. The filtered unpolluted air may then be supplied to the liquid reservoir. When the cleaning liquid is too contaminated it is easy to just empty the cleaning liquid and refill the container with new cleaning liquid. This way, a simple and cost efficient filter arrangement for liquid reservoirs with air inlets is achieved.

The container suitably comprises a top wall, a bottom wall and two side walls. The tube may be inserted into the container via an inlet port of the container. The inlet port may be arranged in the top wall of the container. The filtered air is suitably adapted to leave the container via an outlet port arranged in the top wall of the container.

The container may comprise two or more different cleaning liquids. The different cleaning liquids are suitably immiscible, such that they form separate layers in the container. The different cleaning liquids may thus have different densities. This way, the filtering of the contaminated air may be improved. For example, the container may comprise water and oil as cleaning liquids, thereby comprising two liquid layers.

The container is suitably filled with cleaning liquid up to a certain predetermined level. Suitably, there is always a section of the container available for accommodating the filtered air. The container is thus never completely filled with cleaning liquid. The section for the filtered air is above the cleaning liquid(s), that is, between the surface of the cleaning liquid(s) and the top wall of the container. As an example, the cleaning liquid(s) occupies between 1/2 -2/3 of the total container volume.

The tube suitably extends from the top wall of the container towards the bottom wall. The tube may extend essentially in parallel with the side walls of the container. The tube suitably comprises a tube inlet and a tube outlet. The tube inlet is arranged outside the container in fluid communication with the ambient air and the tube outlet is arranged inside the container in the cleaning liquid. The tube outlet is suitably arranged well below the surface of the cleaning liquid. The tube outlet may be arranged adjacent the bottom wall of the container.

According to an embodiment of the invention the container comprises at least one transparent cleaning liquid. This way, the contaminants are visible in the cleaning liquid and it is possible to see when the cleaning liquid is so contaminated that it should be replaced with new cleaning liquid. There is thus no need for predetermined service/cleaning intervals and cleaning of the filter arrangement can instead be adapted to the actual environmental conditions. In the case where multiple cleaning liquids are used some or all of the different cleaning liquids may be transparent. A flexible and user-friendly filter arrangement is thereby achieved.

The at least one cleaning liquid may be water. Water is cheap and easy to get hold of and would thus be easy to use as cleaning liquid. In some environments, however, it is so cold that water would freeze. Water as cleaning liquid is thus only suitable where there is no risk of freezing. The at least one cleaning liquid may alternatively be urea, which can be found at gas stations and thereby is very accessible. The at least one cleaning liquid may alternatively be glycol with a proper ratio to withstand low temperatures. By having a liquid based filter arrangement according to the invention the cleaning liquid can be determined depending on the application of the filter arrangement. A filter arrangement in a vehicle may, for example, use water as cleaning liquid when the vehicle is used in warm climates, whereas urea or glycol may be used when the vehicle is operating in colder climates. Also, it is possible to alternate between different cleaning liquids depending on availability, such that if there is no urea available at one time, for example glycol can be used instead. A flexible and user-friendly filter arrangement that is suitable for all climates is thereby achieved.

According to an embodiment of the invention the container is configured, such that the cleaning liquid(s) inside the container can be seen from outside the container. The container may thus be transparent or the container may comprise a transparent window. This way, it is easy to determine when the cleaning liquid(s) in the container should be replaced with new unpolluted cleaning liquid. The container may comprise transparent plastics.

According to an embodiment of the invention the filter arrangement further comprises a baffle device arranged inside the container to ensure that the tube end inside the container is immersed in cleaning liquid when the container is tilted. The baffle device is thus adapted to ensure that the tube outlet is below the surface of the cleaning liquid also when the container is tilted. This way is ensured that the contaminated air is passed through the cleaning liquid before reaching the reservoir.

The baffle device may comprise a cylinder surrounding the tube inside the container, the cylinder comprising at least one opening in its envelope surface. The cylinder may comprise a plurality of openings distributed over the envelope surface. It is thereby ensured that cleaning liquid can enter the cylinder and thus that the tube outlet is surrounded by cleaning liquid. The cylinder may extend essentially all the way from the top wall of the container to the bottom wall. The at least one opening in the envelope surface is suitably positioned such that a minimum level of cleaning liquid inside the cylinder is above the tube outlet. The cylinder may comprise plastic or steel.

According to an embodiment of the invention the tube outlet positioned inside the container has a smaller diameter than the rest of the tube. This way, smaller bubbles will be generated and the airflow through the tube outlet will be increased. The tube may comprise a nozzle arranged at the end inside the container, wherein the tube outlet is the outlet of the nozzle. With smaller bubbles the surface area between the air and the cleaning liquid is increased and the filtering of the contaminated ambient air is improved.

According to an embodiment of the invention the tube comprises more than one outlet for distributing the air in different directions into the cleaning liquid. The tube end inside the container may be closed and the tube may comprise two or more outlets in the envelope surface of the tube. Alternatively, the tube comprises a distribution section at the end inside the container, the distribution section extending essentially in parallel with the top wall and/or the bottom wall of the container. The distribution section may extend essentially horizontally. The distribution section may be a conduit with two outlets, for example one outlet at each end of the conduit. The distribution section may be rotatably arranged to the vertically extending part of the tube inside the container. The distribution section may have a streamlined shape, such as an elliptical shape, to reduce the resistance when rotating in the cleaning liquid. By rotating the distribution section the bubbles and thus the contaminations will be better distributed in the cleaning liquid.

According to an embodiment of the invention the filter arrangement further comprises a valve device arranged in fluid communication with the ambient air and the inside of the container. The valve device may be configured to be in an open position when pressure in the container is below a predetermined threshold value. Suitably, the valve device is configured to be in an open position when there is an underpressure below a predetermined threshold value inside the container. The valve device being in an open position means that ambient air can enter the container. There might be situations where the cleaning liquid inside the container has frozen or where the pressure inside the container for some other reason becomes too low. This could break the container and it could also seriously affect the liquid reservoir and the system associated with said liquid reservoir. With the valve device it is ensured that the container will be supplied with ambient air in case of too low pressure inside the container. Thus, the container will be supplied with contaminated air via the valve device and the contaminated air will enter the liquid reservoir. It is, however, considered to be less damaging to supply contaminated air to the liquid reservoir than to supply no air at all.

The valve device may be a pneumatic check valve, such as a ball check valve or similar. The valve device may be configured such that it automatically returns to its closed state when the pressure in the container has increased above the predetermined threshold value.

The valve device may further be configured to be in an open position when the pressure in the container is above a maximum threshold value. Thus, the valve device may be configured to be in an open position when there is a certain overpressure in the container. When the liquid reservoir associated with the filter arrangement is filled with new liquid the air inside the reservoir needs to be discharged somewhere. Since the air inlet in the reservoir is arranged in fluid communication with the container the air from the reservoir will flow into the container. The pressure inside the container will thereby increase. In order not avoid a too high pressure on the cleaning liquid the valve device is configured such that it opens when the pressure is above a maximum threshold value. The air from the reservoir will thereby be discharged via the valve device in the container. Alternatively, the filter arrangement comprises a separate overpressure valve device configured to be in an open position when the pressure in the container is above a maximum threshold value as herein described. The maximum threshold value is suitably a predetermined value depending on the configuration of the container, the cleaning liquid etc.

According to an embodiment of the invention the filter arrangement further comprises means for retaining the ambient air in the cleaning liquid during a predetermined time. Thus, the filter arrangement may comprise means for ensuring that the bubbles generated by the ambient air travel a longer predetermined way through the cleaning liquid. The means for retaining the ambient air in the cleaning liquid during a predetermined time may be baffles, throttles or partition walls leading the bubbles in a certain direction.

According to an embodiment of the invention the filter arrangement further comprises means for reducing the size of generated bubbles in the cleaning liquid. This way, a larger amount of small bubbles is passed through the cleaning liquid and the total surface between the air and the cleaning liquid is thereby increased. The filtering of the contaminated ambient air will thereby be improved. The means for reducing the size of generated bubbles in the cleaning liquid may be a grating arranged over the tube outlet, a partition wall with a plurality of openings or similar.

According to an aspect of the invention an arrangement for supplying a liquid is provided. The arrangement comprising: a reservoir for accommodating the liquid; a pump for retrieving the liquid from the reservoir; and a conduit arranged between the reservoir and the pump, wherein the reservoir comprises an air inlet connected to the ambient air, such that when the pump draws liquid from the reservoir, ambient air is entering the reservoir, and wherein the arrangement further comprises a filter arrangement as described herein. The liquid in the reservoir may be fuel, such as diesel, or urea and the liquid supply arrangement may thus be a part of a fuel system or an exhaust aftertreatment system. Thus, according to an aspect of the invention an arrangement for supplying urea is provided. The arrangement comprising: a reservoir for accommodating the urea; a pump for retrieving the urea from the reservoir; and a conduit arranged between the reservoir and the pump, wherein the reservoir comprises an air inlet connected to the ambient air, such that when the pump draws urea from the reservoir, ambient air is entering the reservoir, and wherein the arrangement further comprises a filter arrangement as described herein.

Further objects, advantages and novel features of the present invention will become apparent to one skilled in the art from the following details, and also by putting the invention into practice. Whereas the invention is described below, it should be noted that it is not restricted to the specific details described. Specialists having access to the teachings herein will recognise further applications, modifications and incorporations within other fields, which are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and further objects and advantages of it, the detailed description set out below should be read together with the accompanying drawings, in which the same reference notations denote similar items in the various drawings, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment of the invention; Figure 2 schematically illustrates an arrangement for supplying a liquid according to an embodiment of the invention; Figure 3 schematically illustrate a filter arrangement according to an embodiment of the invention, Figure 4 schematically illustrate a filter arrangement according to an embodiment of the invention; Figure 5 illustrates a filter arrangement according to an embodiment of the invention; Figure 6 illustrates a filter arrangement according to an embodiment of the invention; and Figure 7 illustrates a filter arrangement according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a side view of a vehicle 1 comprising a propulsion unit 2. The vehicle 1 also comprises an arrangement 100 for supplying a liquid, wherein the arrangement 100 comprises a filter arrangement 10. The arrangement 100 for supplying a liquid may be part of a fuel system or an exhaust aftertreatment system, wherein the liquid being supplied is fuel or urea.

The arrangement 100 for supplying a liquid and the filter arrangement 10 are further described in Figure 2-5. The vehicle 1 may be a heavy vehicle, e.g. a truck or a bus. The vehicle 1 may alternatively be a passenger car. The vehicle may be manually operated, remotely operated or autonomously operated.

Figure 2 schematically illustrates an arrangement 100 for supplying a liquid L according to an embodiment of the invention. The arrangement 100 comprises: a reservoir 120 for accommodating the liquid L; a pump 122 for retrieving the liquid L from the reservoir 120; and a conduit 124 arranged between the reservoir 120 and the pump 122, wherein the reservoir 120 comprises an air inlet 126 connected to the ambient air, such that when the pump 122 draws liquid L from the reservoir 120, air is entering the reservoir 120. The liquid L may be urea. The arrangement 100 further comprises a filter arrangement 10. The filter arrangement 10 comprises: a container 12; and a tube 14 arranged to lead ambient air into the container 12, wherein the container 12 comprises at least one cleaning liquid CL. The container 12 is adapted to be arranged in fluid communication with the air inlet 126 of the reservoir 120, such that ambient air is lead through the cleaning liquid CL in the container 12 before entering the reservoir 120. The air inlet 126 of the reservoir 120 is thus connected to the ambient air via the filter arrangement 10. The container 12 is suitably arranged in fluid communication with the air inlet 126 of the reservoir 120 via a line/tube/pipe 16. The line/tube/pipe 16 connecting the container 12 and the reservoir 120 may be a venting line 16. The reservoir 120 may be filled with the liquid L manually.

By means of the filter arrangement 10 the ambient air is lead into the container 12 via the tube 14 and any particles in the air will be separated from the air and be trapped inside the cleaning liquid CL. The air supplied into the cleaning liquid CL will generate bubbles, which will burst at the surface of the cleaning liquid CL and the filtered air is released while the contaminants remain in the cleaning liquid CL. Thus, when liquid L is withdrawn from the reservoir 120 by means of the pump 122, an underpressure is created in the reservoir which results in filtered clean air from the container 12 passing through the line/tube/pipe 16 via the air inlet 126 into the reservoir 120, whereby ambient air is sucked into the container 12 via the tube 14.

The arrangement 100 may be an arrangement for supplying urea on a vehicle 1 as disclosed in Figure 1. It is, however, to be understood that the filter arrangement 10 can be used in other applications where a liquid reservoir comprises an air inlet 126. The filter arrangement 10 will be further described in Figure 3-Figure 7.

Figure 3 schematically illustrates a filter arrangement 10 according to an embodiment of the invention. The filter arrangement 10 may be configured as disclosed in Figure 2. The filter arrangement thus comprises: a container 12; and a tube 14 arranged to lead ambient air into the container 12, wherein the container 12 comprises at least one cleaning liquid CL. The container 12 is adapted to be arranged in fluid communication with an air inlet 126 of a liquid reservoir 120, such that ambient air is lead through the cleaning liquid CL in the container 12 before entering the liquid reservoir 120.

The container 12 suitably comprises a top wall 20, a bottom wall 22 and two side walls 24’, 24”. The tube 14 may be inserted into the container 12 via an inlet port 30 of the container 12. The inlet port 30 may be arranged in the top wall 20 of the container 12. The filtered air is suitably adapted to leave the container 12 via an outlet port 32 arranged in the top wall 20 of the container 12. The outlet port 32 may be adapted to be connected to a venting line/tube/pipe 16 connected to the air inlet 126 of the liquid reservoir 120. The container 12 may comprise two or more different cleaning liquids CL. The different cleaning liquids CL are suitably immiscible, such that they form separate layers in the container 12. The container 12 is suitably filled with cleaning liquid CL up to a certain predetermined level. Suitably, there is always a section of the container 12 available for accommodating the filtered air. The section for the filtered air is above the cleaning liquid CL, that is, between the surface of the cleaning liquid CL and the top wall 20 of the container 12. The outlet port 32 and any line/tube/pipe 16 connected to the liquid reservoir 120 is suitably arranged well above the surface of the cleaning liquid CL in the container 12. This way is ensured that only filtered air is fed into the reservoir.

The tube 14 suitably extends from the top wall 20 of the container 12 towards the bottom wall 22. The tube 14 may thus extend essentially in parallel with the side walls 24’, 24” of the container 12. The tube 14 suitably comprises a tube inlet 42 and a tube outlet 44. The tube inlet 42 is in fluid communication with the ambient air and the tube outlet 44 is arranged inside the container 12 in the cleaning liquid CL. The tube outlet 44 is suitably arranged well below the surface of the cleaning liquid CL. The tube outlet 44 may be arranged adjacent the bottom wall 22 of the container 12. The tube 14 may for example be a rubber hose, a pipe or similar.

The cleaning liquid CL is suitably transparent. This way, it is possible to see when the cleaning liquid CL is so contaminated that it should be replaced with new cleaning liquid CL. The cleaning liquid may be water, urea, glycol or any other liquid. The container 12 may be configured, such that the cleaning liquid CL inside the container 12 can be seen from outside the container 12. The container 12 may thus be transparent or the container 12 may comprise a transparent window.

The filter arrangement 10 may further comprise means (not shown) for retaining the ambient air in the cleaning liquid CL during a predetermined time. Thus, the filter arrangement 10 may comprise means for ensuring that the bubbles generated by the ambient air travel a longer predetermined way through the cleaning liquid CL. The means for retaining the ambient air in the cleaning liquid during a predetermined time may be baffles, throttles or walls leading the bubbles in a certain direction.

The filter arrangement 10 may also comprise means (not shown) for reducing the size of generated bubbles in the cleaning liquid CL. This way, a larger amount of small bubbles is passed through the cleaning liquid CL and the total surface between the air and the cleaning liquid CL is thereby increased. The filtering of the contaminated ambient air will thereby be improved. The means for reducing the size of generated bubbles in the cleaning liquid CL may be a grating arranged over the tube outlet 44, a partition wall with a plurality of openings or similar.

Figure 4 schematically illustrates a filter arrangement 10 according to an embodiment of the invention. The filter arrangement 10 may be configured as disclosed in Figure 3. In this embodiment the filter arrangement 10 further comprises a baffle device 50 arranged inside the container 12 to ensure that the tube outlet 44 is immersed in cleaning liquid CL when the container 12 is tilted. The baffle device 50 is thus adapted to ensure that the tube outlet 44 is below the surface of the cleaning liquid CL also when the container 12 is tilted or moved. This way is ensured that the contaminated ambient air always is passed through the cleaning liquid CL, thereby ensuring a reliable and good filtering.

The baffle device 50 may comprise a cylinder surrounding the tube 14 inside the container 12, the cylinder 50 comprising at least one opening 52 in its envelope surface. The cylinder 50 may comprise a plurality of openings 52 distributed over the envelope surface as shown in the figure. The cylinder 50 may thus be perforated. It is thereby ensured that cleaning liquid CL can enter the cylinder 50 and thus that the tube outlet 44 is surrounded by cleaning liquid CL. The cylinder 50 may extend essentially all the way from the top wall 20 of the container 12 to the bottom wall 22. The at least one opening 52 in the envelope surface is suitably positioned such that a minimum level of cleaning liquid CL inside the cylinder 12 is above the tube outlet 44. The cylinder 50 may comprise plastic or steel.

Figure 5 schematically illustrates a filter arrangement 10 according to an embodiment of the invention. The filter arrangement may be configured as disclosed in Figure 3 and Figure 4. In this embodiment the tube outlet 44 has a smaller diameter than the rest of the tube 14. The tube 14 thus has a tapered end 46 inside the container 12. This way, smaller bubbles will be generated and the airflow through the tube outlet 44 will be increased. The tube 14 may comprise a nozzle arranged at the end inside the container 12, wherein the tube outlet 44 is the outlet of the nozzle. With smaller bubbles the surface area between the air and the cleaning liquid CL is increased and the filtering of the contaminated ambient air is improved.

Figure 6 schematically illustrates a filter arrangement 10 according to an embodiment of the invention. The filter arrangement 10 may be configured as disclosed in Figure 3, Figure 4 and Figure 5. In this embodiment the filter arrangement 10 comprises a valve device 60 arranged in fluid communication with the ambient air and the inside of the container 12. The valve device 60 is suitably configured to be in an open position when the pressure in the container 12 has decreased below a predetermined threshold value. The valve device 60 is thus suitably configured to be in a closed position when the pressure in the container 12 is above the predetermined threshold value. In the open position ambient air can enter the container 12 via the valve device 60. In the closed position, no ambient air can enter the container 12. The valve device 60 is a safety device, ensuring that air always will be available inside the container 12 for the liquid reservoir 120. The valve device 60 may be a pneumatic check valve, such as a ball check valve or similar. The valve device 60 is suitably configured such that it automatically returns to the closed position when the pressure in the container 12 has increased above the predetermined threshold value.

The valve device 60 may further be configured to be in an open position when the pressure in the container 12 is above a maximum threshold value. Thus, the valve device 60 may be configured to be in an open position when there is a certain overpressure in the container 12. This way, when the liquid reservoir 120 is filled with new liquid L the air inside the reservoir 120 will be discharged via the valve device 60 in the container 12. Alternatively, the filter arrangement 10 comprises a separate overpressure valve device configured to be in an open position when the pressure in the container 12 is above a maximum threshold value as herein described.

Figure 7 schematically illustrates a filter arrangement 10 according to an embodiment of the invention. The filter arrangement 10 may be configured as disclosed in Figure 3, Figure 4, Figure 5 and figure 6. In this embodiment the filter arrangement 10 comprises more than one outlet 44 for distributing the air in different directions into the cleaning liquid CL. The tube 14 may comprise a distribution section 70 at the end positioned inside the container 12. The distribution section 70 may extend essentially horizontally. The distribution section 70 is suitably a conduit with two outlets 44, one at each end of the conduit. Alternatively, the distribution section 70 comprises two conduits arranged as a cross or a plus sign, thereby having four outlets 44 facing in different directions. The distribution section 70 may be rotatably arranged to the rest of the tube 14. The distribution section 70 may have a streamlined shape, such as an elliptical cross section, to reduce the resistance when rotating in the cleaning liquid CL. By rotating the distribution section 70 the bubbles and thus the contaminations will be better distributed in the cleaning liquid CL.

The foregoing description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order best to explain the principles of the invention and its practical applications and hence make it possible for specialists to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims

1. A vehicle filter arrangement (10) for a liquid reservoir (120) with an air inlet (126), the filter arrangement (10) being adapted to be used for a reservoir (120) containing urea or diesel on a vehicle (1), the filter arrangement (10) comprising: a container (12); and a tube (14) arranged to lead ambient air into the container (12), wherein the container (12) comprises at least one cleaning liquid (CL), characterized in that the container (12) is adapted to be arranged in fluid communication with the air inlet (126) of the liquid reservoir (120), such that ambient air is lead through the at least one cleaning liquid (CL) in the container (12) before entering the liquid reservoir (120).

2. The arrangement (10) according to claim 1, wherein the container (12) comprises at least one transparent cleaning liquid (CL).

3. The arrangement (10) according to claim 1 or 2, wherein the container (12) is configured, such that the at least one cleaning liquid (CL) can be seen from outside the container (12).

4. The arrangement (10) according to any one of the preceding claims, further comprising: a baffle device (50) arranged inside the container (12) to ensure that a tube outlet (44) inside the container (12) is immersed in cleaning liquid (CL) when the container (12) is tilted.

5. The arrangement (10) according to claim 4, wherein the baffle device (50) comprises a cylinder surrounding the tube (14), the cylinder comprising at least one opening (52) in its envelope surface.

6. The arrangement (10) according to any one of the preceding claims, further comprising: a valve device (60) arranged in fluid communication with the ambient air and the inside of the container (12).

7. The arrangement (10) according to claim 6, wherein valve device (60) is configured to be in an open position when the pressure inside the container (12) is below a predetermined threshold value.

8. The arrangement (10) according to claim 6 or 7, wherein the valve device (60) is configured to be in an open position when the pressure inside the container (12) is above a predetermined maximum threshold value.

9. The arrangement (10) according to any one of the preceding claims, further comprising: means for forcing the ambient air entering the tube (14) to stay in the at least one cleaning liquid (CL) during a predetermined time.

10. The arrangement according to any one of the preceding claims, further comprising: means for reducing the size of generated bubbles in the cleaning liquid (CL).

11. The arrangement according to any one of the preceding claims, wherein a tube outlet (44) positioned inside the container (12), has a smaller diameter than the rest of the tube (14).

12. The arrangement according to any one of the preceding claims, wherein the tube (14) comprises more than one outlet (44) for directing the air in different directions into the cleaning liquid (CL).

13. An arrangement (100) for supplying urea (L) on a vehicle, the arrangement (100) comprising: a reservoir (120) for accommodating the urea (L); a pump (122) for retrieving the urea (L) from the reservoir (120); and a conduit (124) arranged between the reservoir (120) and the pump (122), wherein the reservoir (120) comprises an air inlet (126) connected to the ambient air, such that when the pump (122) draws urea (L) from the reservoir (120), air is entering the reservoir (120), characterized in that the arrangement (100) further comprises a vehicle filter arrangement (10) according to any one of claims 1-12.

14. Use of a vehicle filter arrangement (10) according to any one of claims 1 -12, for reducing the amount of contaminations in urea stored on a vehicle.

15. A vehicle (1) characterized in that it comprises an arrangement (100) according to claim 13.