DE29817019U1 - Device for cross-flow filtration of liquids - Google Patents

Description

Patent Attorneys Tergau & Pohl, Nuremberg ,'\*"l „"..". ,"

2 Description

Device for cross-flow filtration of liquids

8 The invention relates to a device for cross-flow filtration of liquids.

9 Cross-flow filtration is a process in which the water is

10 Filtration process in which, in contrast to static filtration, the

11 liquid to be filtered or cleaned parallel to a semi-permeable

12 filter surface is circulated. The filter surface is separated from the inner surfaces

13 several ceramic, semi-permeable and essentially cylindrical or

14 rod-shaped filter element is formed, the wall of which is semi-permeable. The

Filter elements are made of aluminum oxide or silicon carbide, for example.

is The proportion of liquid that passes the semi-permeable filter elements in

17 radial direction is called permeate. In an aqueous

18 Suspension or solution, filter elements are used which are practically

19 only allow water molecules to pass through. In this way, permeate can be

20 purified water or as retentate a concentrated solution or suspension

21 can be obtained.

23 As a rule, several filter elements are connected to form parallel bundles.

24, whereby the air supplied to such a bundle or filter module

25 Liquid flow is divided into several individual filter elements

26 parallel partial streams. In this way, the total available

27 standing filter area is increased without, as is the case with a

28 If individual filter elements were connected in series, the

29 Pressure loss would be unacceptably high.

31 Depending on the type of liquid to be cleaned, the inner walls of the

32 filter elements more or less quickly with the retained substances

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Patent attorneys Tergau & Pohl, Nuremberg

&igr; and therefore need to be cleaned from time to time. EP 0 394 532 A1 describes a

2 Device for filtering liquids is described, in which several

3 filter modules enclosed in a separate container in the flow direction

4 are arranged one behind the other. Furthermore, a backwash or

5 Reverse pulse device is present. Each of the containers connected in series is &bgr; connected to a

7 Main supply line connected.

9 The invention is based on the object of providing a device of the type

10, where the technical equipment required for the

11 Repulsion device is reduced.

13 This object is achieved by a device having the features of claim 1

&eegr; is released. After that, all filter elements or filter modules of the device are in

is arranged in a common permeate chamber, which - via a single line

ie with optionally installed shut-off valve - with a return pulse device

&igr;? is fluidically connected. While in the known device a large number of

is separate permeate containers and a variety of lines and shut-off valves

is necessary, the technical equipment required is considerably

20. Another advantage is that during maintenance work or

21 thorough cleaning work on the filter elements only one

22 containers must be opened. Furthermore, with an automatic control

23 of the device to the same extent the control engineering effort for the

24 Operation of the repulsion device reduced.

26 A preferred, space-saving, arrangement of the filter elements is in

27 Claim 2. The filter elements are grouped into several filter modules.

28 The filter elements of a filter module are essentially parallel

29 are arranged next to each other and connected in parallel. Several

The filter modules are arranged one behind the other or connected in series.

si The arrangement of the

32 filter modules.

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Patent attorneys Tergau & Pohl, Nuremberg .··.*": ."..··. ,*'

2 An advantageous mounting of the filter elements is mentioned in claim 4. The

3 has the advantage that the four-lip seal used in ceramic

4 filter elements can be compensated for better than is the case with O-rings. The

6 essential square or rectangular four-lip seal is located with two

7 sealing lips on the circumference of the filter elements. It is easy to see

β that a filter element diameter that is larger than the nominal size

9 without significantly increasing the size of the filter element

10 acting surface pressure can be compensated. In the areas between

11 the radial gap between the filter element and the carrier plate penetrates under

12 Pressurized retentate fluid enters and deforms the four-lip seal

13 elastically or presses the sealing lip acted upon by it against the peripheral surface &eegr; of the filter element.

ie A particularly advantageous and inventive embodiment is

17 in claim 5. The carrier plate is then a plastic plate, which

is provided on both sides with a reinforcing plate made of a metallic material,

19 preferably made of steel or stainless steel. First of all, this is a

20 significant weight savings. The mechanical stability of the

21 proposed "sandwich panel" is completely unsuitable for the intended purpose.

22 is sufficient. Furthermore, this design simplifies the

23 Manufacturing the carrier plate. While a completely metal

24 existing carrier plate the necessary for storing the filter elements 2s receiving openings are machined in a technically complex manner into the

26 Solid material of the carrier plate would have to be drilled, this can be done with a

27 Plastic plate during its production by injection moulding on less

28 complex manner. It is conceivable to use a metal plate as the carrier plate

29 cast iron plate, in which the above-mentioned receiving openings are also

30 are already planned in advance. However, such a metal casting process is already

31 more complex because practically a new mould has to be made for each casting

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Patent attorneys Tergau & Pohl, Nuremberg ,"."'I .·*..·*. ."

&igr; must be. In addition, the walls of the receiving openings

2 be reworked.

4 The carrier plates are preferably connected by means of substantially parallel to the

5 filter elements are fixed to each other by spacer struts (claims 7 and &bgr; 8). Further advantageous embodiments are mentioned in claims 9-15,

7 In particular, the design according to claim 14 ensures that

βgr; no air cushion accumulates in the permeate space, which in case of back pulsation

9 would prevent or at least hinder the pressure build-up in the permeate space.

10 In claims 10 -12, an advantageous possibility for forming a

11 retentate channels of two in the flow direction connected one behind the other

12 connecting channel, whereby this channel also

13 is designed to be aerodynamically efficient.

is The invention will now be described with reference to an embodiment shown in the accompanying drawings

The illustrated embodiment is explained in more detail. They show:

is Fig.1 A functional diagram of an inventive

is device,

20 Fig.2 a device with two filter modules

21 containing permeate space in longitudinal section,

22 Fig.3 a cross section along the line HI-III in Fig.2 and

23 Fig.4 a detail section marked IV in Fig.2 in

24 enlarged view.

26 Fig.1 shows the basic structure and functionality of a

27 device according to the invention. In a permeate container 1

28 enclosed permeate space 2 are two filter modules 3,4 next to each other

29. The filter modules each comprise several filter elements, which are arranged parallel to one another and - in terms of flow - parallel

31 are connected. In the schematic representation according to Fig.1, the

32 filter modules 3,4 for simplification reasons only two filter elements 5. The

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Patent attorneys Tergau & Pohl, Nuremberg .··."*: .'·..·*. .".Since«

&igr; filtering liquid or the retentate is circulated and flows,

2 driven by a pump 6 several times through the filter elements 5.

3 The liquid flow leaving the pump 6 is controlled according to the number of

4 filter elements 5 of a filter module are divided into partial flows 7,8. At the

5 The output side of a filter module, the partial flows 7,8 are

6 and via a connecting channel 9 to the

7 Flow direction 10 passed on to the following filter module. At its

β input side, a branching takes place into partial streams T and 8' and

9 on the output side a summary of the partial flows in a discharge channel 11.

10 A storage tank 12 is connected to the retentate circuit mentioned above. The

11 Permeate penetrating the filter elements essentially in the radial direction is

12 is continuously withdrawn via a permeate line 15 and fed, for example, into a

13 collection container 16. The amount of permeate separated from the &eegr; retentate stream that has passed into the permeate chamber 2 is discharged from a container 17 via

is a motor-driven refill pump 18 is constantly replaced. The permeate line

is branched off at a point as high up as possible on the permeate tank in order to

&igr;? to prevent the accumulation of a gas-air mixture cushion in the container.

18 Cleaning of the filter modules is carried out using the cleaning

19 common permeate chamber a repulsion device 19 is connected. This

20 essentially comprises a pump 20, which via a return pulse line 21

21 for example retentate from the collecting container 16 under high pressure,

22 preferably with pulsations and at intervals into the permeate chamber 2.

23 The retentate penetrates the filter elements and dissolves solid accumulations from

24 the walls of the retentate channels. A device of the type described

25 can be used, for example, for wastewater treatment or for the production of

26 Use fruit juice concentrates etc.

28 In Fig.2 a preferred embodiment of a device according to the invention is

29 Device shown in longitudinal section, in whose permeate chamber 2 two filter modules 3a and 4a are also arranged. Each filter module comprises, &zgr;. &Bgr;.

31 eight filter elements 5, which are arranged in a circular cross-section,

32 Circumferential direction of a substantially tubular section-shaped

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Patent Attorneys Tergau & Pohl, Nuremberg .".'"I .*·..·*. .".See 6

&igr; Permeate container 1a is enclosed. The filter module 3a is in one half 23 and

&zgr; the filter module 4a in the other half 24 of the permeate chamber 2 or the

3 permeate container 22 (see Fig.3). The filter elements 5 of the

4 filter modules 3a,4a are divided into two to the diameter 25 of the permeate container

5 parallel and spaced rows 26,27,

β where the row 26 closest to the diameter 25 contains four filter elements and the row further

7 row 27 removed therefrom comprises three filter elements.

9 The filter elements 5 are each located with their end areas in a

10 Carrier plate 29 penetrates the receiving opening 28. The carrier plate

11 consists essentially of a plastic plate 33, which is provided on both sides with a

12 Reinforcing plate 34,35 with coaxially arranged to the receiving openings

13 through holes 28a. The support plates 29,29a are

14 spacer struts 36 are connected to each other. The spacer struts 36 run in the

is essentially parallel to the filter elements 5 and have at their end areas

Each has an internal thread that ends in its front side, into which a

&igr;? Through hole 37 of the carrier plate 29,29a

is fastening screw 38 is screwed in. In the wall of the

ig through hole 37 there is a radial groove in which a sealing ring 39

20. The permeate container 1a has two terminal

21 mounting flanges 42,43, which extend radially from its peripheral surface

22 extend outside. The mounting flanges 42,43 are supported by several

23 fixing holes 44. On the mounting flange 42 is located under

24 Intermediate layer of a seal 45 a dome-shaped cover 46 with a

25 also has a counter flange 47 which extends radially outwards and which in turn

26 is penetrated by several fixing holes 48 which are coaxial to the

27 fixing holes 44 of the mounting flange 42 are arranged. Within the

28 cover 46 is a wedge-shaped downwardly tapering partition 49

29, which rests with its lower end on the carrier plate 29 and which thus ends with an axial distance in front of the upper cover wall 50. The partition wall 49

31 extends along the diameter line 25 (Fig.3) and borders on the

32 side wall 51 of the cover 46. In this way, a connecting channel 52

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Patent attorneys Tergau & Pohl, Nuremberg . \ "&Iacgr; .··..". .".gfefie

·

&igr; which connects the filter elements of the filter module 3a with the filter elements of the

2 filter module 4a. The side wall 51 of the cover 46 is

3 conical and tapered towards the upper cover wall 50. The thickness of the

4 Partition wall 49 decreases steadily from its free end to the support plate 29. The

5 Cross-section U-shaped connecting channel 52 thus has two

&bgr; streamlined legs 54,55. The leg 54 narrows -

7 starting from its leg end - in the flow direction 10, whereas

β of the leg 55 approximately from the free end of the partition wall 49 in the flow direction

9, it expands continuously up to the carrier plate 29. The wedge angle &agr;

Ø of the partition wall 49 and the cone angle of the side wall 51 are each

11 maximum 14°. The partition wall 49 is provided with three through holes 56

12, which are coaxial to the distributed on the diameter 25

13 spacer struts 36a, 36b and 36c are arranged. In the through holes

&eegr; are fastening screws 57, the head 58 of which rests on a radial shoulder 59

is of the through hole 56 and which is threaded into a frontal

The internal thread of a spacer strut 36a,36b,36c engage. The upper

&igr;? Carrier plate 29 is arranged outside the permeate container 22 and borders with

is sealingly attached to a sealing wall 60 of the cover 46 at its side edge.

19 Such a sealing wall could be attached to the inside of the pipe section-shaped

20 permeate container due to its high manufacturing tolerances

21 is more difficult to realize. In the edge of the carrier plate 29 there is a circumferential groove

22, in which a sealing ring 61 is located.

24 At the lower end of the permeate container 23 is a base 62

25 formed lid is attached. The base 62 is basically a

26 Pipe section, which is closed at the bottom by a base plate 63. In the

27 A feed channel 69 and a discharge channel 70 are arranged on the base.

29 The base 62 has at its upper end a radially outwardly extending

thus extending counter flange 73, with which it is attached to the mounting flange 43 of the

31 permeate container 1a. The counter flange 73 is provided with several

32 through holes 74 which are coaxial with the fixing holes 44 of the

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Patent attorneys Tergau & Pohl, Nuremberg . *. * . .·*..". .".SfeTtg

&igr; mounting flange 43. The carrier plate 29a extends

2 between flanges 43 and 73.

4 Approximately in the middle of the permeate container 1a there is a connection 76 which

5 can be connected to the return pulse device 19 (Fig.1). Near the

A pressure gauge connection 77 is arranged on the mounting flange 42. A

&tgr; comparable connection 78 is located near the mounting flange 43.

&bgr; This connection is used to empty the permeate chamber or to connect

9 of a pressure gauge. At the top of the cover 46 is a lockable

10 vent connection 79 is formed. In the position defined by the counter flange 47 and the

11 cover wall formed a permeate connection 96 is arranged to

12 the permeate accumulating in the permeate chamber 22 via a

13 Permeate outlet channel 98 (Fig.1) to be able to withdraw. In the permeate chamber

14 also escapes via the permeate outlet channel 98.

is For sealing the end areas of the filter elements 5 in the

17 receiving openings 28 are located in a circumferential radial groove in the wall

ie has a ring-shaped, approximately square cross-section four-lip seal 84. The

19 Sealing lips 85 of this sealing ring point approximately - seen in cross section - into the

20 four corners of a square and thus extend approximately star-shaped

21 away from each other. Two of the sealing lips 85a,85b are located on the peripheral surface of the

22 filter element 5. Between the wall of the receiving opening 28 and the

23 filter element 5 is arranged a radial gap 81. The other sealing lips 85c

24 and 85d are supported on the wall of the receiving opening 28. In the

25 external reinforcement plate 35 has several through holes 86

26, which are coaxial with the receiving openings 28 of the plastic plate 33

27. Pressurized fluid that has penetrated into the radial gap

The retentate acts on the sealing lip 85a and presses it in the direction of arrow 97 against

29 the filter element.

31 The filter elements 5 are approximately rod-shaped ceramic bodies with approximately

32 circular cross-section. They are longitudinally connected by several parallel and

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Patent Attorneys Tergau & Pohl, Nuremberg ,".'"I ,"..", .*·. g^te 9

Radially spaced retentate channels 90 pass through (Fig. 3). In the area of the wall 91 of the retentate channels, the ceramic material is compressed or has a microporosity that ensures the semi-permeability of the filter elements. The remaining ceramic material of the filter elements 5, on the other hand, has larger pores. The microporous wall 91 of the retentate channels 90 forms a semi-permeable membrane that retains the components to be filtered out of the liquid, such as dirt particles from waste water or, if designed accordingly, even much smaller particles such as germs or the like.

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Patent attorneys Tergau & Pohl, Nuremberg

List of reference symbols Permeate tank 35 Reinforcement plate 1 Permeate chamber 36 Spacer 2 Filter module 37 Through hole 3 Filter module 38 Fixing screw 4 Filter element 39 Sealing ring 5 pump 42 Mounting flange 6 Partial flow 43 Mounting flange 7 Partial flow 44 Fixing hole 8th Connecting channel 45 poetry 9 Flow direction 46 Lid 10 Discharge channel 47 Counter flange 11 Storage container 48 Fixing hole 12 Permeate line 49 partition wall 15 Collection container 50 Cover wall 16 container 51 Side wall 17 Refill pump 52 Connecting channel 18 Back pulse device 53 Central longitudinal axis 19 pump 54 leg 20 Return pulse line 55 leg 21 half 56 Through hole 23 half 57 Fixing screw 24 diameter 58 Head 25 Row 59 Radial shoulder 26 Row 60 Sealing wall 27 Receiving opening 61 Sealing ring 28 Passage opening 62 Stand 28a Carrier plate 63 Footplate 29 Plastic plate 69 Feed channel 33 Reinforcement plate 70 Discharge channel 34

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Patent Attorneys Tergau & Pohl, Nuremberg .**· "**&idigr; .**..", «**.»56&EEgr;&rgr; 2

71 Through hole 72 Fixing screw 73 Counter flange 74 Through hole 75 poetry 76 Connection 77 Pressure gauge connection 78 Connection 79 Vent connection 81 Radial gap 84 Four-lip seal 85 Sealing lip 90 Retentate channel 91 Wall 92 Passage opening 93 Fixing screw 94 Access opening 95 screw 96 Permeate connection 97 Arrow direction 98 Permeate outlet channel

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Claims (1)

Expectations 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 1. Device for cross-flow filtration of liquids with several essentially rod-shaped or cylindrical semi-permeable filter elements (5) penetrated by one or more retentate channels (90), characterized, that all filter elements (5) of the device are arranged in a common permeate chamber (2) which is fluidically connected to a repulsion device (19). 2. Device according to claim 1, characterized in that the filter elements (5) are grouped in several filter modules (3a,4a), - wherein the filter elements (5) of a filter module are arranged essentially parallel next to one another and - with regard to a flow through with a liquid or a retentate - are connected in parallel and - whereby the filter modules are arranged one behind the other in terms of flow or connected in series. 3. Device according to claim 2, characterized, that the filter modules (3a, 4a) are arranged next to one another, with their filter elements (5) aligned parallel to one another. 4. Device according to claim 3, characterized, (N:\AN\98846-1.DOC) last saved: September 22, 1998 Patent Attorneys Tergau & Pohl, Nuremberg · J »" · ··,,;.*····**· Page &igr; that the end areas of the filter elements (5) are in compliance with a 2 radial gaps (81) each lie in a receiving opening (28) which has a 3 extending transversely to the longitudinal axis of the filter elements (5), the 4 retentate channels (90) sealing towards the permeate chamber (2) 5 carrier plate (29,29a), whereby the radial gap (81) is 6 between the wall of the receiving opening (28) and the peripheral surface of the 7 filter elements (5) effective, in cross-section essentially square β or rectangular four-lip seal (84). 10 5. Device according to claim 3 or 4, 11 characterized by 12 that the carrier plate (29,29a) is designed as a sandwich plate, wherein a 13 Plastic plate (33) on both sides with a reinforcement plate (34,35) made of &eegr; a metallic material, in particular made of stainless steel it is. &igr;? 6. Device according to claim 5, ie characterized by is that the plastic plate (33) is an injection-molded part. 21 7. Device according to one of claims 4-6, 22 characterized by 23 that the carrier plates (29,29a) are connected by means of substantially parallel to the 24 spacer struts (36) running between the filter elements (5) are fixed to each other. 26 8. Device according to claim 11, 27 characterized by 28 that the spacer struts (36) are provided with a through hole (37) of the 29 Support plate (29,29a) from the outside of which penetrates and with such a front-side internal thread of the spacer struts (36) si cooperating fastening screw (38) fixed to the carrier plate 32, wherein in the wall of the through opening (37) a (N:\AN\98846-1.DOC) last saved: September 22, 1998 Patent Attorneys Tergau & Pohl, Nuremberg · I . · J·..; , *»·&iacgr;·**· Page A sealing ring (39) cooperating with the fastening screw (38) is embedded. 4 9. Device according to one of claims 1-8, 5 characterized by 6 that the permeate chamber (2) in the circumferential direction 7 Permeate container (1 a) from a pipe section oval or round β cross-sectional shape, the terminal, extending from its peripheral surface 9 radially outwardly extending, penetrated by fixing holes (44) 10 mounting flanges (42,43). 12 10. Device according to claim 9, 13 characterized by 14 that a substantially dome-shaped cover (46) is fixed to the one fastening flange (42), which has at least one The retentate channels (90) of two in the flow direction connected one behind the other &igr;? Filter modules (3a,4a) interconnected connecting channel (52), ie wherein the connecting channel is formed by the wall of the cover (46) and a 19 partition wall (49) is formed, which extends across the cover 20 and adjoins its side wall (51), wherein the 21 Partition wall on the one hand seals with the carrier plate (29) and 22 on the other hand ends at a distance in front of the upper cover wall (50). 24 11. Device according to claim 10, 25 characterized by 26 that the partition wall (49) tapers in a wedge shape towards the carrier plate (29), and 27 that the side wall (51) is conical towards the upper cover wall (50) 28 tapered. 30 12. Device according to claim 11, 31 characterized by (N-.\AN\98846-1.DOC) last saved: September 22, 1998 Patent Attorneys Tergau & Pohl, Nuremberg _m ° *· . J &iacgr; *».J * »Sterte* 1 a wedge angle α of the partition wall (49) and a cone angle β of the 2 side wall (51) of maximum 14°. 4 13. Device according to one of claims 9-12, 5 characterized by 6 that on the other mounting flange (43) a substantially 7 tubular section-shaped base (62) is fixed, which comprises a feed channel (69) and β a discharge channel (70), wherein the feed channel (69) is connected to the first 9 Filter module (3a) and the discharge channel (70) with the last filter module (4a) of the 10 filter modules arranged in the permeate chamber (22) - each in 11 flow direction - is connected. 13 14. Device according to one of claims 1-13, 14 characterized by is that a permeate outlet channel (98) from the highest point of the the permeate chamber (2) opens to the outside. is 15. Device according to one of claims 1 -14, 19 characterized by 20 a vertical alignment of the filter modules (3a,4a) or the filter elements (5). (N:\AN\98846-1.DOC) last saved: September 22, 1998