DE102011111454B4 - Device and method for filtration with a band-shaped filter medium - Google Patents

Abstract

Device (1) for filtering a liquid (2) to be filtered with a band-shaped filter medium (4) which can be continuously conveyed in its longitudinal direction from a supply (3) via a predetermined path (5) to a reservoir (6) for used filter material and can be exposed to a negative pressure towards the filtrate side, a filtrate chamber (8) which can be acted upon by the negative pressure being delimited by the filter medium (4) towards an unfiltrate space (7) facing away from the filtrate side, the filtrate chamber (8) facing the unfiltrate space (7). a cover (9) which is permeable to liquid at least in some areas and is curved parallel to the longitudinal direction of the filter medium (4) towards the unfiltrate space (7), which in turn is covered towards the unfiltrate space (7) by the filter medium (4) and opposite the side walls (10) surrounding it , 11, 12, 13) of the filtrate chamber (8) is sealed and forms a fixed support surface over which the filter medium (4) can be conveyed, a drive (33) with a drive roller (34) for conveying the filter medium (4), a pump (36) for generating the negative pressure and a control and regulation unit (37) for controlling the drive (33) and the pump (36) are provided and the filtrate chamber (8), the unfiltrate chamber (7) and the filter medium ( 4) including the supply (3) and reservoir (6) are encapsulated and designed for single use.

Description

Field of invention

The invention relates to a device for filtering a liquid to be filtered with a band-shaped filter medium.

State of the art

Filtration devices with continuously moving, band-shaped filter medium are from the US 4,233,157 A known.

From the DE 42 09 054 A1 is a device for filtration of a liquid to be filtered with a band-shaped filter medium, which is conveyed in its longitudinal direction from a supply roll over a predetermined path by means of deflection rollers and a drive roller to a reservoir for used filter material. The used filter material is wound onto a roll in the reservoir. The web-shaped filter material, which delimits an unfiltrate space from a filtrate chamber, is acted upon from the unfiltrate side with the liquid to be filtered, which can be conveyed as filtrate into the filtrate chamber with the aid of a negative pressure generated in the filtrate chamber.

The disadvantage here is that the filtrate chamber is essentially open to the unfiltrate space and is covered by a circumferential, endless carrying belt with a plurality of support surfaces. The carrying strap is relatively complex and consists of a large number of individual parts and is relatively cost-intensive. Sealing the filtrate chamber in order to prevent unfiltrate from entering the filtrate chamber must be carried out in a relatively complex manner using a plurality of pressure rollers for pressing the band-shaped filter material against the side edges of rails of the filtrate chamber.

Next is from the EP 1 832 325 B1 a device for filtration of a liquid to be filtered with a band-shaped filter medium, which is conveyed in its longitudinal direction from a supply roll over a predetermined path by means of deflection rollers and a drive roller to a reservoir for used filter material, is known.

Here too, an endless carrying or supporting band is provided, which presses the band-shaped filter medium against the predetermined path in a device housing.

The disadvantage of the known devices is that they are relatively complex and cost-intensive.

The DE 39 00 746 A1 discloses a device for filtering a liquid to be filtered with a band-shaped filter medium, which has an unfiltrate chamber, a filter band wound on a supply roll and a filtrate chamber that can be subjected to negative pressure. The unfiltrate chamber is separated from the filtrate chamber by a cover which runs parallel to the horizontal and has holes for filtrate and which has the shape of a sieve bottom. The device also has a deflection roller for the used filter belt, which can be wound onto a driven reel. The filtrate can be removed from the filtrate chamber via a filter pump system.

A disadvantage of the known device is that the band-shaped filter medium is only moved gradually over a liquid-permeable cover of the lower filtrate chamber, since in the path of the filter medium on the filtrate side of the filtrate chamber there is a separate antechamber upstream of the filtrate chamber, which leads to the premature build-up of a filter cake on the filtrate chamber in question Filter medium section is assigned a circulation pump unit for the circulation of a liquid containing the solids for the filter cake structure.

The EP 0 778 064 A2 discloses a device for filtration of a liquid to be filtered with a band-shaped filter medium, which has an unfiltrate chamber (movable second filter cell part), a filter band wound on a supply roll and a pressurized filtrate chamber (first filter cell part). The device has a base element with a base plate on which two side walls are mounted, between which the first filter cell element is arranged in the form of a stationary press table in their respective U-shaped recesses. The second filter cell element is arranged between the two side walls in the form of a stamp that can be moved in the vertical direction. A filter belt is passed from a supply roll between the first and second filter cell parts and, after filtration, is transported away through the transport roll and through the counter-pressure roll. The press table and the stamp each clamp circular disks in the filter belt in a cycle specified by a control device, which is synchronized with the guidance of the filter belt through the rollers and through which the filtration takes place, with the unfiltrate being fed through the line to the filter disk and the filtrate is discharged through the line.

Disadvantageous in the from the EP 0 778 064 A2 known device is that the band-shaped filter medium/filter medium is only released for conveyance after filtration has taken place in order to replace the filter medium with unused filter medium replace so that a new filtration can then be carried out, so that individual filtrations can be carried out repetitively one after the other. Another disadvantage is that the filtration speed in the known device is not influenced by the conveying speed of the filter medium, since in the case of a filtration flow the filter medium is not moved, ie the conveying speed is zero.

The US 4,079,010 A discloses a device for continuous belt filtration, consisting of an unfiltrate chamber inclined at an acute angle to the horizontal and a filtrate chamber with an outlet for filtrate. The unfiltrate chamber is separated from the filtrate chamber by a support plate provided with drainage holes for filtrate, over which an endless belt with a filtering effect is guided in a longitudinally movable manner, on which filter aids and particles from the solution to be filtered are retained.

Disadvantageous in the from the US 4,079,010 A Known device is that the filter medium is designed as an endless belt, so that after one cycle no fresh filter medium is fed, but only filter medium cleaned on its outside by a cleaning roller.

From the US 4,233,157 A is a device for filtration of a liquid to be filtered with a band-shaped filter medium, which is conveyed in its longitudinal direction from a supply over a predetermined path to a reservoir for used filter material. The filter medium is exposed to a negative pressure on the filtrate side. In this case, a filtrate chamber to be subjected to the negative pressure is delimited by the filter medium from an unfiltrate space facing away from the filtrate side. The filtrate chamber has a liquid-permeable cover towards the unfiltrate space, which in turn is covered by the filter medium towards the unfiltrate space and forms a fixed support surface over which the filter medium is conveyed. Furthermore, a drive with a drive roller for conveying the filter medium, a pump for generating the negative pressure and a control and regulation unit for controlling the drive and the pump are provided. In addition, small embodiments of the filter system can be used to filter blood or other biological substances, whereby the device must be completely isolated from the environment in order to guarantee sterility or to prevent the escape of potentially toxic components.

The disadvantage of the known device is that the filter medium can only be conveyed in steps, i.e. sequentially, since in order to transport the filter medium the unfiltrate chamber must first be emptied and the upper housing part with the unfiltrate space must be lifted off the filter medium via the pressure cylinder. In addition, the filter medium is not maximally stretched over the cover, so it can slip off the side of the cover as it moves. Another disadvantage is that the filtration speed in the known device is not influenced by the conveying speed of the filter medium, since in the case of a filtration flow the filter medium is not moved, i.e. the conveying speed is zero.

Task

The object of the present invention is therefore to provide a device and a method for filtering a liquid to be filtered with a band-shaped filter medium, which are relatively simple, safe, time-saving and inexpensive, with the filter medium slipping sideways from the cover as the filter medium moves is avoided.

Presentation of the invention

The object is achieved by a device with the features of claim 1, ie by a device for filtering a liquid to be filtered with a band-shaped filter medium which can be continuously conveyed in its longitudinal direction from a supply via a predetermined path to a reservoir for used filter material and to The filtrate side can be exposed to a negative pressure, a filtrate chamber which can be acted upon by the negative pressure being delimited by the filter medium towards an unfiltrate space facing away from the filtrate side,
wherein the filtrate chamber towards the unfiltrate space has a cover which is liquid-permeable at least in some areas and is curved parallel to the longitudinal direction of the filter medium towards the unfiltrate space, which in turn is covered by the filter medium towards the unfiltrate space and is sealed against the side walls of the filtrate chamber surrounding it and forms a fixed support surface which the filter medium can be conveyed, wherein a drive with a drive roller for conveying the filter medium, a pump for generating the negative pressure and a control and regulation unit for controlling the drive and the pump are provided and wherein the filtrate chamber, the unfiltrate space and the filter medium including storage and reservoir are encapsulated and designed for single use.

By dispensing with a carrying belt that can be conveyed in its longitudinal direction and arranging a fixed, liquid-permeable one Covering the structure of the device is considerably simplified and more cost-effective. Through the forward movement of the filter materials and the pump setting, the filter cake thickness can be adjusted or regulated via the control and regulation unit. In order to prevent unfiltrate from entering the filtrate chamber from the side, the cover is sealed from the surrounding side walls of the filtrate chamber. By sealing or embedding the cover in relation to the filtrate chamber, the security against unwanted entry of unfiltrate into the filtrate chamber is further increased.

According to the invention, the cover is curved parallel to the longitudinal direction of the filter medium towards the unfiltrate space. This convex curvature of the cover in the direction of the unfiltrate space allows the filter medium to be guided over the cover with greater tension and thus to prevent the filter medium from slipping sideways from the cover when the filter medium is moving.

The encapsulated design of the device creates new possible uses, which in particular enable the sterile use of the device. Due to the simple, cost-effective design, which can do without metal parts, the device can be intended for single use. In particular, the sterile use of the device in combination with a bioreactor is now also possible. This means that it is now also possible to use the device for cell harvesting.

According to a preferred embodiment of the invention, the cover is flat transversely to the longitudinal direction of the filter medium. The flat design of the cover transversely to the longitudinal or conveying direction of the filter medium also contributes to the aforementioned advantages.

According to a preferred embodiment of the invention, the cover is designed as a perforated plate with a plurality of holes. However, the cover can also be designed, for example, as a liquid-permeable sintered plate.

For secure sealing, the cover has a liquid-tight edge strip on its opposite long sides and transverse sides, which is at least partially covered by the filter medium. The edge strip can also be formed by the side walls or their end faces, in which the cover is embedded.

According to a preferred embodiment of the invention, the filtrate chamber with the cover is inclined downwards at an acute angle in the longitudinal direction compared to the horizontal. The filtrate chamber is connected at its lower end to an upwardly directed transverse wall, for example via an intermediate wall running in a horizontal direction.

The cover, together with the transverse wall connected to it and optionally with the intermediate wall and two side walls of a device housing arranged on the opposite longitudinal sides of the filtrate chamber, forms a receiving trough for the liquid to be filtered.

According to a further preferred embodiment of the invention, the filter medium is designed in multiple layers and the layers with different filter properties are wound up in the supply on one or separate supply rolls. Different filter materials, such as fleeces, paper or membrane filters, which have different filter properties, are used. In principle, the supply can also be removed from a container in which the filter medium is arranged folded.

According to a further preferred embodiment of the invention, the used filter medium can be collected in the reservoir designed as a collecting container. The used filter material can also be wound onto a roll arranged in the reservoir.

According to a further preferred embodiment of the invention, a stripping device for stripping off filter cake that has formed on the filter medium and a collecting container for collecting the filter cake are provided. The filter cake can also be wound onto the roll for the used medium.

The object relating to the method is achieved in conjunction with the preamble of claim 13 in that the filter cake thickness of a filter cake settling on the filter medium towards the unfiltrate side is controlled by a control and regulating device by controlling the conveying speed of the filter medium and by controlling the filter cake produced in the filtrate chamber negative pressure is controlled,
whereby at a high flow it is necessary to work with a fast conveying speed of the filter medium with a reduced filter capacity and at a low flow it is possible to work with a slow conveying speed of the filter medium with an increased filter capacity.

With a high flow, the filter medium must be conveyed at a fast speed, which reduces the filter capacity reduced. If the flow is low, the filter medium can be conveyed at a slow speed, thereby increasing the filter capacity.

According to a preferred embodiment of the invention, the conveying speed is controlled by controlling a drive connected to a drive roller of the filter medium and the negative pressure of the filtrate chamber is controlled by a pump connected to the filtrate chamber.

Further details of the invention emerge from the following detailed description and the accompanying drawings, in which preferred embodiments of the invention are illustrated by way of example.

Brief description of the drawings

• 1: eine schematische Seitenansicht einer Vorrichtung zur Filtration mit einem bandförmigen Filtermedium,
• 2: eine Draufsicht auf eine Vorrichtung zur Filtration mit einem bandförmigen Filtermedium in verkleinerter Darstellung mit Antrieb,
• 3: eine Draufsicht auf die Vorrichtung von 2 mit zwei angekoppelten weiteren Vorrichtungen ohne Antrieb als Erweiterungsmodule, die den Antrieb der ersten Vorrichtung nutzen;
• 4: eine räumliche Darstellung, schräg von vorn, einer weiteren ungekapselten Vorrichtung zur Filtration mit einem bandförmigen Filtermedium;
• 5: die Vorrichtung von 4 in räumlicher Darstellung schräg von der Rückseite her gesehen;
• 6: eine Seitenansicht einer weiteren Vorrichtung zur Filtration mit einem bandförmigen Filtermedium in gekapselter Darstellung, bei der das verbrauchte Filtermedium samt Filterkuchen auf eine Rolle aufgewickelt wird und
• 7: eine weitere Darstellung einer Vorrichtung zur Filtration mit einem bandförmigen Filtermedium in gekapselter Darstellung, bei der das verbrauchte Filtermedium auf eine Rolle aufgewickelt wird, wobei eine Abstreifvorrichtung den Filterkuchen von dem verbrauchten Filtermedium abstreift.

Shown in the drawings:

• 1 : a schematic side view of a device for filtration with a band-shaped filter medium,
• 2 : a top view of a device for filtration with a band-shaped filter medium in a reduced representation with a drive,
• 3 : a top view of the device from 2 with two coupled additional devices without a drive as expansion modules that use the drive of the first device;
• 4 : a spatial representation, diagonally from the front, of another unencapsulated device for filtration with a band-shaped filter medium;
• 5 : the device of 4 in a spatial representation seen obliquely from the back;
• 6 : a side view of another device for filtration with a band-shaped filter medium in an encapsulated representation, in which the used filter medium including the filter cake is wound onto a roll and
• 7 : a further representation of a device for filtration with a band-shaped filter medium in an encapsulated representation, in which the used filter medium is wound onto a roll, with a stripping device stripping the filter cake from the used filter medium.

Description of the exemplary embodiments

A device 1 for filtering a liquid 2 to be filtered essentially consists of a supply 3 with band-shaped filter medium 4, a predetermined path 5, an unfiltrate space 7 and a filtrate chamber 8.

The filtrate chamber 8 extends below the unfiltrate space 7. Towards the unfiltrate space 7, the filtrate chamber 8 has a liquid-permeable cover 9, which in turn is covered by the band-shaped filter medium 4. The cover 9 forms the ceiling of the filtrate chamber 8 and is embedded in it and sealed on its side edges opposite side walls 10, 11, 12, 13 of the filtrate chamber 8.

According to the exemplary embodiment of 1 the cover 9 has a plurality of holes 14 through which filtrate filtered by the filter medium 4 enters the filtrate chamber 8.

According to another embodiment, not shown, the cover 9 is designed as a liquid-permeable sintered plate, the openings of which are covered by the band-shaped filter medium 4.

The cover 9 has a liquid-tight edge strip on its opposite longitudinal sides 15, 16, which is at least partially covered by the band-shaped filter medium 4.

The filtrate chamber 8 is according to the exemplary embodiments 1 and 4 to 7 with the cover inclined downwards in the longitudinal direction relative to the horizontal by an acute angle 17 and connected at its lower end 18 via a connecting wall 19 running in the horizontal direction to a transverse wall 20 directed upwards in the vertical direction. The transverse wall 20 can correspond to the exemplary embodiment 1 run vertically upwards or according to the exemplary embodiment of 4 and 5 run diagonally upwards away from the cover 9, so that it creates free space for the supply 3. The cover 9 forms with the transverse wall 20, the connecting wall 19 and the side walls 21, 22 of a device housing 23 arranged on the opposite longitudinal sides of the filtrate chamber 8 a receiving trough 24 for the liquid 2 to be filtered. The receiving trough 24 thus essentially forms the unfiltrate space 7 .

According to the exemplary embodiments of 1 , 6 and 7 the band-shaped filter medium 4 is designed in two layers, with a first layer 25, which is wound on a first roll 26, forming, for example, a coarse pre-filter and a second layer 27, which is wound on a second roll 28, forming a fine filter. Fleece, paper or membrane filters with various types of filter media are available which properties are in question. The multi-layer filter medium 4 can also be wound with its different layers 25, 27 in the supply 3 on a common supply roll, not shown.

According to the 1 the used band-shaped filter medium 4 can be collected in the reservoir 6 designed as a collecting container 29.

According to the exemplary embodiments of 6 and 7 the used filter medium 4 can be wound onto a third roll 30 arranged in the reservoir 6.

While according to the exemplary embodiment 6 the used filter medium 4 with the filter cake 31 is wound onto the third roll 30, according to the exemplary embodiment 7 the filter cake 31 is stripped and collected from the band-shaped filter medium 4 with a stripping device 32, so that the used filter medium 4 is wound onto the third roll 30 without filter cake 31.

According to a further embodiment, a web material made of a porous membrane is fixed on the liquid-permeable cover 9. In this embodiment, a fleece is guided over the cover 9 as a band-shaped filter medium 4, which transports the filter cake 31 formed into the reservoir 6 during its longitudinal movement over the cover 9.

To convey the band-shaped filter medium 4 there is a drive 33 with a drive roller 34 and, if necessary, corresponding 1 provided with a counter-pressure roller 35.

To the extent that the used filter medium 4 is not placed loosely in a collecting container 29, but rather accordingly 6 and 7 is wound directly onto a roll 30, a counter-pressure roll is not necessary and the third roll 30 can simultaneously be designed as a drive roll 34.

A pump 36 is provided to generate a negative pressure in the filtrate chamber 8.

A control and regulation unit 37 is connected to the drive 33 and the pump 36.

According to the exemplary embodiments of 6 and 7 The filtrate chamber 8, the unfiltrate chamber 7 and the filter medium 4 including the supply 3 and reservoir 6 are encapsulated and intended or suitable for single use.

This is a device 1 according to the exemplary embodiments 6 and 7 to be used for sterile applications in combination with a bioreactor, e.g. B. for precoat filtration processes. In particular, such a device 1 can be used for cell harvesting.

For filtration, the band-shaped filter medium 4 is conveyed in its longitudinal direction from the supply 3 via a path 5 predetermined by deflection rollers 38 and the cover 9 to the reservoir 6 for used filter medium 4. The filter medium 4 is exposed to a negative pressure on the filtrate side, which is generated in the filtrate chamber 8 by the pump 36.

During the filtering process, a filter cake 31 forms on the filter medium 4 towards the unfiltrate side, the thickness of which is controlled via the control and regulation unit 37 by controlling the conveying speed and the negative pressure generated by the pump 36. The control and regulation unit 37 therefore controls the conveying speed of the filter medium 4 via the drive 33 and the negative pressure in the filtrate chamber 8 via the pump 36.

In principle, the filter medium 4 can be conveyed continuously or gradually in its longitudinal direction.

The device housing 23 of the device 1 is intended so that further devices 39 without their own drive 33 can be coupled laterally to the first device 1 as expansion modules and use the drive 33 of the first device 1.

Reference symbol list

1

contraption

2

filtering liquid

3

stock

4

band-shaped filter medium

5

predetermined path

6

reservoir

7

Unfiltrate space

8th

Filtrate chamber

9

Coverage of 8

10

Side wall of 8

11

Side wall of 8

12

Side wall of 8

13

Side wall of 8

14

Hole from 9th

15

Long side of 9

16

Long side of 9

17

acute angle

18

bottom end of 8

19

connecting wall

20

transverse wall

21

Side wall of 23

22

Side wall of 23

23

Device housing

24

receiving tray

25

first layer of 4

26

first role

27

second layer of 4

28

second role

29

Collection container

30

third roll of 6

31

Filter cake

32

Stripping device

33

drive

34

Drive roller

35

Counter pressure roller

36

pump

37

Control and regulation unit

38

pulley

39

other devices

Claims (14)

Device (1) for filtering a liquid (2) to be filtered with a band-shaped filter medium (4) which can be continuously conveyed in its longitudinal direction from a supply (3) via a predetermined path (5) to a reservoir (6) for used filter material and can be exposed to a negative pressure towards the filtrate side, a filtrate chamber (8) which can be acted upon by the negative pressure being delimited by the filter medium (4) towards an unfiltrate space (7) facing away from the filtrate side, the filtrate chamber (8) facing the unfiltrate space (7). a cover (9) which is permeable to liquid at least in some areas and is curved parallel to the longitudinal direction of the filter medium (4) towards the unfiltrate space (7), which in turn is covered towards the unfiltrate space (7) by the filter medium (4) and opposite the side walls (10) surrounding it , 11, 12, 13) of the filtrate chamber (8) is sealed and forms a fixed support surface over which the filter medium (4) can be conveyed, a drive (33) with a drive roller (34) for conveying the filter medium (4), a pump (36) for generating the negative pressure and a control and regulation unit (37) for controlling the drive (33) and the pump (36) are provided and the filtrate chamber (8), the unfiltrate chamber (7) and the filter medium ( 4) including the supply (3) and reservoir (6) are encapsulated and designed for single use. Device according to Claim 1 , characterized in that the cover (9) is designed as a perforated plate with a plurality of holes (14). Device according to Claim 1 , characterized in that the cover (9) is designed as a liquid-permeable sintered plate. Device according to one of the Claims 1 until 3 , characterized in that the cover is flat transversely to the longitudinal direction of the filter medium (4). Device according to one of the Claims 1 until 4 , characterized in that the cover (9) has a liquid-tight edge strip on its opposite long sides and transverse sides, which is at least partially covered by the filter medium (4). Device according to one of the Claims 1 until 5 , characterized in that the filtrate chamber (8) with the cover (9) is inclined downwards in the longitudinal direction relative to the horizontal by an acute angle (17) and is connected at its lower end (18) to an upwardly directed transverse wall (20). is, the cover (9) with the transverse wall (20) connected to it and two side walls (10, 11, 12, 13) of a device housing (23) arranged on the opposite longitudinal sides (15, 16) of the filtrate chamber (8). Receiving tray (24) forms for the liquid (2) to be filtered. Device according to one of the Claims 1 until 6 , characterized in that the filter medium (4) is designed in multiple layers and the layers (25, 27) with different filter properties in the supply (3) are wound on one or separate supply rolls (26, 28). Device according to one of the Claims 1 until 7 , characterized in that the used filter medium (4) can be collected in the reservoir (6) designed as a collecting container (29). Device according to one of the Claims 1 until 7 , characterized in that the used filter medium (4) can be wound onto a roll (30) arranged in the reservoir (6). Device according to one of the Claims 1 until 9 , characterized in that a stripping device (32) for stripping off filter cake (31) and a collecting container (29) is provided for collecting the filter cake (31). Use of a device (1) according to one of Claims 1 until 10 for sterile applications in combination with a bioreactor. Use after Claim 11 , characterized in that the device (1) is used for cell harvesting. Method for filtering a liquid (2) to be filtered using a device (1) according to one of Claims 1 until 10 , characterized in that the filter cake thickness of a filter cake (31) settling on the filter medium (4) towards the unfiltrate side is determined by a control and regulating device (37) by controlling the conveying speed of the filter medium (4) and by controlling the flow rate in the filtrate chamber (8 ) generated negative pressure is controlled, whereby at a high flow it is necessary to work with a fast conveying speed of the filter medium with a reduced filter capacity and at a low flow it is possible to work with a slow conveying speed of the filter medium with an increased filter capacity. Procedure according to Claim 13 , characterized in that the conveying speed is controlled by a drive (33) connected to a drive roller (26, 28) of the filter medium (4) and the negative pressure of the filtrate chamber (8) is controlled by a pump (36) connected to the filtrate chamber (8). ) being controlled.

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