FILTER SYSTEM

Abstract

The filter system includes a feed hose (10) arranged along a permeate hose (20), wherein the feed hose (10) and the permeate hose (20) include a membrane (7) as the common wall section, and wherein the permeate hose (20) is closed at the front end and includes a permeate outlet (29) at the rear end. A fluid to be prepared flows in a pressurized state through the feed hose (10). At the end of the feed hose, a first fraction of the fluid flows through a retentate outlet (25) out of the feed hose (10). A further fraction of the fluid moves through pores of the membrane (7) into the permeate hose (20). This fraction flows through a permeate outlet (25) at the end of the permeate hose (20), separate from the retentate, and out of the filter system.

Claims

1. A filter system comprising: at least one filter element (5), which comprises a permeate hose (20), said permeate hose (20) limits a secondary flow chamber, is closed at a front end thereof, and comprises a permeate outlet (29) at a rear end thereof, at least a portion of the wall of said permeate hose (20) is a membrane (7) comprising pores, and the pores connect the secondary flow chamber to a primary flow chamber, the membrane (7) is at least a part of a wall of a feed hose (10), which is arranged along the permeate hose (20) and which limits the primary flow chamber, and the feed hose (10) comprises a feed inlet (25) at a front end thereof and a retentate outlet (23) spaced apart in a longitudinal direction of the feed hose (10) from the feed inlet, at a rear end thereof.

2. The filter system as claimed in claim 1, wherein the wall of the permeate hose (20) comprises an inner hose and an outer hose encasing the inner hose, and the inner hose forms the feed hose (10) comprising the membrane (7).

3. The filter system as claimed in claim 1, the wall of the feed hose (10) comprises an inner hose and an outer hose encasing the inner hose, wherein the inner hose forms the permeate hose (20) comprising the membrane (7).

4. The filter system as claimed in claim 1, wherein the feed hose (10) and the permeate hose (20) are arranged adjacently next to one another, and the membrane (7) is a common section of the walls of the feed hose (10) and of the permeate hose (20).

5. The filter system as claimed in claim 1, wherein the at least one filter element (5) is a wound module that is wound spirally around a collector tube (1) that includes collector openings (3), and the permeate outlet (29) at an inner side of the permeate hose (20) is arranged in a region of the collector tube (1) and is connected to the collector tube (1) via the collector openings (3).

6. The filter system as claimed in claim 5, wherein an intermediate space between adjoining layers of the at least one rolled-up filter element (5) at each of two front sides of the wound module is at least partially sealed by a sealing element (21).

7. The filter system as claimed in claim 6, wherein the primary flow chamber or the secondary flow chamber is limited by the adjoining layers of the at least one rolled-up filter element (5) and by the front-side sealing elements (21).

8. The filter system as claimed in claim 7, wherein the wound module is arranged in a housing (31), the housing (31) comprises a housing jacket (33), which is covered by an input-side cover (35) comprising at least one input opening (37) and by an output-side cover (45) comprising at least one output opening (47).

9. The filter system as claimed in claim 8, wherein at least one of (a) a front sealing body (41) is arranged between the input-side cover (35) and the wound module, said front sealing body seals the intermediate spaces between the adjoining layers of the at least one filter element (5) on a front side, and which comprises at least one recess (43), which connects the input opening (37) to the feed inlet (25), or (b) a rear sealing body (51) is arranged between the output-side cover (45) and the wound module, said rear sealing body seals the intermediate spaces between the adjoining layers of the at least one filter element (5) on a rear side, and which comprises at least one recess (53), which connects the output opening (47) to the retentate outlet (23).

10. A method for preparing a liquid using a filter system, wherein said filter system comprises a feed hose (10), which is arranged along a permeate hose (20), the permeate hose (20) is closed on a front end and comprises a permeate outlet (29) on a rear end, and a membrane (7) comprising pores is a common wall section of the feed hose (10) and of the permeate hose (20), the method comprising: the liquid flowing into the feed hose (10) under pressure through a feed inlet (23) at a front end of the feed hose, a fraction of the liquid flowing through the feed hose (10) along the permeate hose (20) and flowing out through a retentate opening (25) at an end of the feed hose (10), and a further fraction of the liquid moving through the pores of the membrane (7) into the permeate hose (20) and flowing out of the permeate hose (20) through the permeate outlet (29).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will be described in more detail below on the basis of some figures, in which

[0034] FIG. 1 shows a cut-open conventional wound module,

[0035] FIG. 2 shows an unwinding of a conventional wound module with delineated flow directions,

[0036] FIG. 3 shows an unwinding of a wound module according to the invention with delineated flow directions,

[0037] FIG. 4 shows a cutout of a simplified wound module in a first viewing direction,

[0038] FIG. 5 shows the cutout of the wound module from FIG. 4 in a second viewing direction,

[0039] FIG. 6 shows a cutout of a simplified wound module in a first viewing direction,

[0040] FIG. 7 shows the cutout of the wound module from FIG. 4 in a second viewing direction,

[0041] FIG. 8 shows a longitudinal section of a filter system.

DETAILED DESCRIPTION

[0042] FIG. 1 shows a cut-open wound module of a known filter system. It comprises a central collector tube 1, the wall of which has several continuous collector openings 3. A multi-layer filter element 5, which comprises a membrane 7 and two further layers 9 adjacent to the membrane 7, is wound spirally around the collector tube 1. The ends of the collector tube 1 protrude beyond the wound-up filter element 5 on both front sides. The open ends of the collector tube 1 are filtrate outlets 11. The spiral intermediate space between the layers of the wound-up filter element 5 is open toward both front sides. The liquid to be purified streams as feed through this intermediate space in the axial direction. This is illustrated symbolically by means of feed arrows 13. On the opposite front side, a fraction of the feed streams out of the wound module in the axial direction. This is illustrated symbolically by means of retentate arrows 15. In the wound module, a fraction of the feed permeates small pores of the membrane 7 (not illustrated), and is guided spirally to the collector tube 1 as filtrate or permeate, respectively, on the opposite side of the membrane 7 transversely to the feed stream. This is illustrated symbolically by means of permeate arrows 17. There, the filtrate reaches through the collector openings 3 into the collector tube 1, and is subsequently discharged in the axial direction via the filtrate outlets 11. This is illustrated symbolically by means of arrows 19.

[0043] For illustration purposes, FIG. 2 shows the feed stream of such an arrangement when the filter element 5 is unwound.

[0044] FIG. 3 shows the feed stream in the case of a filter system according to the present invention in an analogous manner. Along the two longitudinal edges of the filter element 5, strip-shaped sealing elements 21 are arranged such that they tightly close the intermediate spaces between adjacent layers of the filter element 5 on the front side at a wound module comprising wound-up filter element 5.

[0045] At least one of the sealing elements 21 does not extend over the entire length of the filter element 5. Adjacent to the collector tube 1, a comparatively small section of at least one of the longitudinal edges of the filter element 5 is formed without sealing element 21 at the rear end of the filter element 5. Adjacent to the collector tube 1, at least one retentate outlet 23, thus an opening, through which retentate can escape from a primary flow chamber, is thus created at a wound module comprising wound-up filter element 5. The primary flow chamber is the intermediate space between adjoining layers of the wound-up filter element 5. At the rear end of the filter element 5, the primary flow chamber is sealed off from the collector tube 1. At the front end, thus at the radially outer jacket surface of the wound module, the primary flow chamber between the sealing elements 21 comprises a tangentially accessible feed inlet 25.

[0046] In the alternative or in addition, a comparatively small section of at least one of the longitudinal edges of the filter element 5 could be formed without sealing element 21 at the front end of the filter element 5. In this case, the wound module has at least one feed inlet 25 (not illustrated), which is accessible on the front side. In the case of such embodiments of the wound module, the feed inlet 25, which is arranged tangentially on the jacket surface, can be tightly closed. This is advantageous in particular when the wound-up filter element or filter elements 5 of the wound module are encased and/or held together (not illustrated), e.g. by means of a protective film.

[0047] A simplified cutout of a wound module comprising three layers of a wound-up filter element 5 is illustrated in FIG. 4 with a view onto the front end of the filter element 5 and in FIG. 5 with a view onto the rear end of the filter element 5. The filter element 5 comprises a twin hose, wherein a feed hose 10, which limits a primary flow chamber, and a permeate hose 20, which limits a secondary flow chamber, are separated from one another by means of a porous membrane 7 within a tight covering hose 27. The open front end of the feed hose 10 is a feed inlet 25. In the alternative or in addition, feed inlets 25 on the front end of the filter element 5 can also be arranged laterally as openings in the wall of the covering hose 27, as is illustrated in FIG. 4 by means of dashed lines at a narrow side and at a broad side of the feed hose 10. The feed arrows 13 symbolically show the inflow of a liquid to be purified through the feed inlets 25 into the feed hose 10. The permeate hose 20 is closed at the front end. The open rear end of the permeate hose 20 is a permeate outlet 29. In the alternative or in addition, permeate outlets 29 at the rear end of the filter element 5 can also be arranged laterally as openings in the wall of the covering hose 27, as is illustrated in FIG. 5 by means of dashed lines on a narrow side and on a broad side of the permeate hose 20. The permeate arrows 19 symbolically show the outflow of the filtrate through the permeate outlets 29 from the permeate hose 20. The permeate outlets 29 are connected to the collector openings 3 of the collector tube 1 such that escaping permeate can be guided into the collector tube 1 separately from the feed and from the retentate (not illustrated). At the end of the feed hose 10, one or several openings are formed as retentate outlets 23 such that the retentate can be discharged from the feed hose 10 separately from the permeate. The retentate arrows 15 symbolically show the outflow of the retentate through the retentate outlets 23 out of the feed hose 10.

[0048] The filter element 5 can be wound onto the collector tube 1 such that the feed hose 10 is arranged radially on the outside or radially on the inside of the permeate hose 20.

[0049] In the feed hose 10 and/or in the permeate hose, structures can optionally be formed or liquid-permeable layers can be arranged as spacers, ensure the flow-through of liquid in the respective hose (not illustrated). Alternatively to a filter element 5, several filter elements 5 can also be wound spirally around the collector tube 1 jointly. In the case of the wound-up wound module, layers of different filter elements 5 are thus adjacent to one another. The feed inlets 25 of all filter elements 5 are preferably connected to a common input opening in a manner brought together in a housing. All retentate outlets 23 are analogously brought together and are connected to an output opening. The permeate outlets 23 connected accordingly to the collector tube 1, which comprises one or several openings as filtrate outlets 11.

[0050] Analogously to FIGS. 4 and 5, FIGS. 6 and 7 show a simplified cutout of a further wound module comprising three layers of a wound-up alternative filter element 5. In contrast to the embodiment according to FIGS. 4 and 5, the alternative filter element 5 comprises only a permeate hose 20. The feed hose 10 is created only when winding up the filter element 5 by sealing the intermediate space between the adjoining layers along the longitudinal edges of the filter element 5. The primary flow chamber is thus limited by means of two adjoining layers of the filter element 5 and by means of front-side sealing elements 21.

[0051] FIG. 8 shows a longitudinal section of a filter system, wherein a wound module is installed into an essentially cylindrical housing 31. The housing 31 is arranged coaxially to the collector tube 1. It comprises a cylindrical housing jacket 33, which encloses the wound module and which is covered on the front side by a cover 35 on the input side and by a cover 45 on the output side. The collector tube 1 permeates these covers 35 axially in both directions. The entry-side cover 35 comprises input openings 37, through which a liquid to be purified can flow as feed under pressure into the housing 31. Between the cover 35 and the front front side of the wound module, a front sealing body 41 as sealing element 21 covers the intermediate spaces between adjoining layers of one or several filter elements 5. The front sealing body 41 comprises at least one recess 43, which connects the input openings 37 to the feed inlet 25. The escape-side cover 45 comprises output openings 47, through which the retentate can flow out of the housing 31. Between the cover 45 and the rear front side of the wound module, a rear sealing body 51 as sealing element 21 covers the intermediate spaces between adjoining layers of the filter element or filter elements 5, respectively. The rear sealing body 51 comprises at least one recess 53, which connects the output openings 47 to the retentate outlet 23.