FILTRATION SYSTEM AND METHOD FOR FILTERING WATER

Abstract

The invention relates to filtration system (20), comprising a tank (40) filled at least partly with water to be filtered, and at least one filtration module (30), the at least one filtration module (30) comprising at least one filter membrane (10) for filtering the water comprising a substrate (12) which is penetrated by at least one capillary (16), and at least one filtrate pipe (32) for drawing filtered water out of the tank (40), whereat the at least one filtration module (30) is arranged in the tank (40) such that the at least one filter membrane (10) is submerged at least partly in the water to be filtered. The at least one filtration module (30) is designed and arranged such that water to be filtered flows into the at least one capillary (16) and from the at least one capillary (16) through the substrate (12) into the filtrate pipe (32). The invention also relates to a method for filtering water by means of a filtration system (20) according to the invention, whereat the water to be filtered is drawn into the at least one capillary (16) and from the at least one capillary (16) through the substrate (12) into the filtrate pipe (32) and from the filtrate pipe (32) out of the tank (40).

Claims

1. Filtration system (20), comprising a tank (40) filled at least partly with water to be filtered, and at least one filtration module (30), the at least one filtration module (30) comprising at least one filter membrane (10) for filtering the water comprising a substrate (12) which is penetrated by at least one capillary (16), and at least one filtrate pipe (32) for drawing filtered water out of the tank (40), whereat the at least one filtration module (30) is arranged in the tank (40) such that the at least one filter membrane (10) is submerged at least partly in the water to be filtered, characterized in that the at least one filtration module (30) is designed and arranged such that water to be filtered flows into the at least one capillary (16) and from the at least one capillary (16) through the substrate (12) into the filtrate pipe (32).

2. Filtration system (20) according to claim 1, characterized in that the at least one filter membrane (10) comprises several capillaries (16) penetrating the substrate (12), whereat the several capillaries (16) are separated from each other by parts of the substrate (12).

3. Filtration system (20) according to one of the preceding claims, characterized in that the at least one filter membrane (10) has a cylindrical shape extending in an axial direction (x), with the at least one capillary (16) also extending in the axial direction (x).

4. Filtration system (20) according to claim 3, characterized in that the at least one filtrate pipe (32) extends in the axial direction (x) parallel to the at least one filter membrane (10), and in that the at least one filtrate pipe (32) is penetrated by openings (38) extending in a radial direction such that water flows from the at least one filter membrane (10) through the openings (38) into the at least one filtrate pipe (32).

5. Filtration system (20) according to one of claims 3 to 4, characterized in that the at least one filtration module (30) comprises a casing (34) extending in the axial direction (x) and surrounding the at least one filter membrane (10) and the at least one filtrate pipe (32) in circumferential direction.

6. Filtration system (20) according to claim 5, characterized in that the at least one filtration module (30) comprises at least one sealing (36) arranged within the casing (34) in a region near a front side (15) of the at least one filter membrane (10), surrounding the at least one filter membrane (10) and the at least one filtrate pipe (32) in circumferential direction.

7. Filtration system (20) according to claim 6, characterized in that at least one front side (15) of the at least one filter membrane (10) is free from the sealing (36) such that water can enter the at least one capillary (16) in the axial direction (x).

8. Filtration system (20) according to claim 7, characterized in that the at least one filtration module (30) is arranged in the tank (40) such that the at least one front side (15) of the at least one filter membrane (10) that is free from the sealing (36) is in contact with the water.

9. Filtration system (20) according to one of claims 3 to 8, characterized in that the at least one filtration module (30) is arranged in the tank (40) such that the axial direction (x) extends vertically.

10. Filtration system (20) according to claim 9, characterized in that the at least one filtration module (30) is arranged in the tank (40) such that the at least one filtrate pipe (32) extends out of the water.

11. Filtration system (20) according to one of claims 3 to 8, characterized in that the at least one filtration module (30) is arranged in the tank (40) such that the axial direction (x) extends horizontally.

12. Filtration system (20) according to one of the preceding claims, characterized in that the at least one filtration module (30) is arranged in the tank (40) such that the at least one filter membrane (10) is submerged completely in the water.

13. Filtration system (20) according to one of the preceding claims, characterized in that several filtration modules (30) are provided, whereat the filtrate pipes (32) of several filtration modules (30) are connected to at least one collecting pipe (42).

14. Filtration system (20) according to one of the preceding claims, characterized in that a suction pump is provided for drawing water through the filtrate pipe (32) of the at least one filtration module (30) out of the tank (40).

15. Method for filtering water by means of a filtration system (20) according to one of the preceding claims, whereat the water to be filtered is drawn into the at least one capillary (16) and from the at least one capillary (16) through the substrate (12) into the filtrate pipe (32) and from the filtrate pipe (32) out of the tank (40).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] For a better understanding of the afore-mentioned embodiments of the invention as well as additional embodiments thereof, reference is made to the description of embodiments below in conjunction with the appended drawings showing:

[0037] FIG. 1 a schematically given top view at a filter membrane;

[0038] FIG. 2 a schematically given cross sectional view at a filtration module;

[0039] FIG. 3 a schematically given perspective semi-transparent view at a filtration system according to a first embodiment; and

[0040] FIG. 4 a schematically given perspective semi-transparent view at a filtration system according to a second embodiment.

[0041] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The drawings only provide schematic views of the invention. Like reference numerals refer to corresponding parts, units or components throughout the figures unless indicated otherwise.

DESCRIPTION OF EMBODIMENTS

[0042] FIG. 1 shows a schematically given top view at a filter membrane 10. The filter membrane 10 has a cylindrical shape, in particular a circular cylindrical shape, which extends in an axial direction x. A front side 15 of the filter membrane 10 extends perpendicular to said axial direction x. The filter membrane 10 comprises a substrate 12 which is porous and semi-permeable. Thus, the substrate 12 allows permeate, such as pure water, to pass and holds back suspended particles or microorganisms as retentate. The substrate 12 can be made of a polymer, in particular a soluble thermoplastic polymer.

[0043] The filter membrane 10 comprises several capillaries 16 penetrating the substrate 12. In this embodiment, the filter membrane 10 comprises seven capillaries 16 that are arranged next to each other and that are surrounded by the substrate 12. Thereat, one of the capillaries 16 is arranged in the middle of the filter membrane 10, and the other six capillaries 16 form a regular hexagon. The seven capillaries 16 are separated from each other by parts of the substrate 12. The capillaries 16 extend parallel to each other in the axial direction x. Thereat, the capillaries 16 also have a cylindrical shape, in particular a circular cylindrical shape.

[0044] Each of the capillaries 16 forms an inner surface 13 within the substrate 12. Said inner surfaces 13 are directed towards the centres of the capillaries 16. The substrate 12 forms an outer surface 17 surrounding the substrate 12 which is directed outwards in a radial direction. Water to be filtered enters the substrate 12 through said inner surface 13 of the capillaries 16, passes through the substrate 12, and the water exits the substrate 12 through said outer surface 17. A sum of the areas of the inner surfaces 13 of all capillaries 16 within the substrate 12 is larger than an area of the outer surface 17.

[0045] FIG. 2 shows a schematically given cross sectional view at a filtration module 30 that extends substantially in the axial direction x. The filtration module 30 comprises a casing 34 that is made of a material which is not porous and which is not permeable for water. For example, the casing 34 is made of Polyvinylchloride (PVC). The casing 34 has a hollow cylindrical shape that extends in the axial direction x and that defines a hollow space inside.

[0046] The filtration module 30 further comprises several filter membranes 10 as shown in FIG. 1 and one filtrate pipe 32. The filter membranes 10 and the filtrate pipe 32 are arranged such that the casing 34 surrounds the filter membranes 10 and the filtrate pipe 32 in circumferential direction. Thereat, the filtrate pipe 32 is arranged in a central area of the casing 34, and the filter membranes 10 surround the filtrate pipe 32. But also different arrangements of the filtrate pipe 32 and the filter membranes 10 are possible.

[0047] As mentioned already, the filter membranes 10 have a cylindrical shape and extend in the axial direction x. Both front sides 15 of the filter membranes 10 align with the front ends of the casing 34 in axial direction. The filtrate pipe 32 has a hollow cylindrical shape defining a hollow space inside. The filtrate pipe 32 also extends in the axial direction x. Thus, the filtrate pipe 32 extends parallel to the filter membranes 10. One front end of the filtrate pipe 32 aligns with one front end of the casing 34 in the axial direction x. The other front end of the filtrate pipe 32 overtops the casing 34 in the axial direction x.

[0048] The filtration module 30 comprises sealings 36 that are arranged within the casing 34 at both regions near the front sides 15 of the filter membranes 10. Said both regions are arranged at opposite ends of the casing 34 in the axial direction x. The sealings 36 each surround the filter membranes 10 and the filtrate pipe 32 in circumferential direction. The sealings 36 are made of a material which is not permeable for water, for example a resin. Hence, the hollow space inside the casing 34 is circumscribed by said two sealings 36 in axial direction x.

[0049] The front end of the filtrate pipe 32 which aligns with the front end of the casing 34 in axial direction x is also closed by means of the sealing 36. Within a region that is located inside the casing 34 and in axial direction x between the sealings 36, the filtrate pipe 32 is penetrated by openings 38 that extend in a radial direction. Hence, water that is located in the hollow space within the casing 34 can flow through said openings 38 into the hollow space within the filtrate pipe 32.

[0050] The front sides 15 of the filter membranes 10 are free from the sealings 36. Hence, water to be filtered can enter the capillaries 16 of the filter membranes 10 at the front sides 15 in the axial direction x. The water to be filtered then flows from the capillaries 16 through the substrates 12 of the filter membranes 10 into the hollow space within the casing 34. The water also flows from the hollow space within the casing 34 through the openings 38 into the hollow space within the filtrate pipe 32. The filtered water can be drawn out of the filtrate pipe 32, for example by means of a suction pump.

[0051] The sealings 36 prevent water from flowing in the axial direction x besides the filter membranes 10 into the hollow space of the casing 34 of the filtration module 30. Thus, water can enter the hollow space inside the casing 34 only by entering the capillaries 16 of the filter membranes 10 and passing through the substrates 12. Hence, only water that has been filtered by the filter membranes 10 may enter the hollow space within the filtrate pipe 32 and can be drawn out of the filtrate pipe 32.

[0052] FIG. 3 shows a schematically given perspective semi-transparent view at a filtration system 20 according to a first embodiment. The filtration system 20 comprises a tank 40 that is filled with water to be filtered up to a water level 50. The filtration system 20 further comprises several filtration modules 30 as shown in FIG. 2. The filtration modules 30 each comprise several filter membranes 10 for filtering the water and a filtrate pipe 32 for drawing filtered water out of the tank 40.

[0053] The filtration modules 30 are arranged in the tank 40 such that the filter membranes 10 are submerged completely in the water. Hence, the filtration modules 30 are arranged in the tank 40 such that the front sides 15 of all filter membranes 10 are located below the water level 50. Thus, the front sides 15 of the filter membranes 10 are in contact with the water.

[0054] In this first embodiment, the filtration modules 30 are arranged in the tank 40 such that the axial direction x extends vertically. The filtration modules 30 are arranged within one line. Thereat, the filtrate pipes 32 of the filtration modules 30 extend above the water level 50 out of the water. The filtration modules 30 are fixed in the tank 40 such that movement within the tank 40 is prevented.

[0055] The filtrate pipes 32 of the filtration modules 30 are connected to a collecting pipe 42 via connection tubes 44. The collecting pipe 42 has a tubular shape and extends horizontally. Hence, the collecting pipe 42 extends perpendicular to the filtrate pipes 32 of the filtration modules 30. Thereat, the collecting pipe 42 is arranged above the water level 50 and hence outside of the water. The collecting pipe 42 is the only connection between the several filtration modules 30 that are arranged in one line.

[0056] A suction pump which is not shown here is provided for drawing filtered water out of the tank 40. The suction pump is connected to the collecting pipe 42. The suction pump generates negative pressure, that means pressure which is smaller than atmospheric pressure, in order to draw water through the collecting pipe 42, through the filtrate pipes 32 and through the filter membranes 10 out of the tank 40.

[0057] FIG. 4 shows a schematically given perspective semi-transparent view at a filtration system 20 according to a second embodiment. The filtration system 20 comprises a tank 40 that is filled with water to be filtered up to a water level 50. The filtration system 20 further comprises several filtration modules 30 as shown in FIG. 2. The filtration modules 30 each comprise several filter membranes 10 for filtering the water and a filtrate pipe 32 for drawing filtered water out of the tank 40.

[0058] The filtration modules 30 are arranged in the tank 40 such that the filter membranes 10 are submerged completely in the water. The filtration modules 30 are arranged in the tank 40 such that the front sides 15 of all filter membranes 10 are located below the water level 50. Thus, the front sides 15 of the filter membranes 10 are in contact with the water.

[0059] In this second embodiment, the filtration modules 30 are arranged in the tank 40 such that the axial direction x extends vertically. The filtration modules 30 are arranged within several lines that extend parallel to each other. Thereat, the filtrate pipes 32 of the filtration modules 30 extend above the water level 50 out of the water. The filtration modules 30 are fixed in the tank 40 such that movement within the tank 40 is prevented.

[0060] The filtrate pipes 32 of the filtration modules 30 which are arranged within the same line are connected to a collecting pipe 42 via connection tubes 44. Each collecting pipe 42 comprises several segments that are connected to one another by ferrules. The segments of the collecting pipe 42 each have a tubular shape and extend horizontally. Hence, the collecting pipe 42 extends perpendicular to the filtrate pipes 32 of the filtration modules 30. Thereat, the collecting pipe 42 is arranged above the water level 50 and hence outside of the water. The segments of the collecting pipe 42 are the only connection between the several filtration modules 30 that are arranged in one line.

[0061] As the 30 filtration modules 30 are arranged within several lines that extend parallel to each other, the filtration system 20 also comprises several collecting pipes 42 that extend parallel to each other. Thereat, each of the several collecting pipes 42 comprises several segments that are connected to one another by ferrules. The several collecting pipes 42 are connected to a collecting vessel 46. The collecting vessel 46 has a tubular shape and extends in a direction perpendicular to the collecting pipes 42. The collecting vessel 46 also extends in a direction perpendicular to the filtrate pipes 32. A diameter of the collecting vessel 46 is bigger than a diameter of the collecting pipes 42.

[0062] A suction pump which is not shown here is provided for drawing filtered water out of the tank 40. In this second embodiment, the suction pump is connected to the collecting vessel 46. The suction pump generates negative pressure, that means pressure which is smaller than atmospheric pressure, in order to draw water through the collecting vessel 46, through the collecting pipe 42, through the filtrate pipes 32 and through the filter membranes 10 out of the tank 40.

[0063] The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings and those encompassed by the attached claims. The embodiments were chosen and described in order to explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

LIST OF REFERENCE NUMERALS

[0064] 10 filter membrane

[0065] 12 substrate

[0066] 13 inner surface

[0067] 15 front side

[0068] 16 capillary

[0069] 17 outer surface

[0070] 20 filtration system

[0071] 30 filtration module

[0072] 32 filtrate pipe

[0073] 34 casing

[0074] 36 sealing

[0075] 38 opening

[0076] 40 tank

[0077] 42 collecting pipe

[0078] 44 connection tube

[0079] 46 collecting vessel

[0080] 50 water level

[0081] x axial direction