The present application claims the benefit of priority of International Patent Application No. PCT/EP2008/000793 filed on Jan. 31, 2008, which claims priority of European Patent Application No. 07004460.7 filed Mar. 5, 2007. The entire text of the priority application is incorporated herein by reference in its entirety.
The present disclosure relates to a filter device, in particular for the filtration of beer, and a corresponding method.
During the manufacture of beer, the yeast cells and other solids contained in the beer must be removed. Such substances must be separated off so that they do not separate off by themselves over the time and make the beer turbid. As the yeast has a particle size of about 5 to 10 μm, it is necessary to use so-called microfilters that work, for example, within a range of 10-1 to 10-2 μm. Up to now, the beer has mainly been filtered by means of precoat filters, e.g. by means of filter cartridges. With such precoat filters, up to now diatomite is mainly used as filter aid. Due to the toxicity of diatomite and the problems of disposing of the same, one is looking for alternatives to this technology. For example, crossflow filter modules offer one alternative, however, they only have a small filter capacity and moreover get clogged very quickly.
Starting from this, the object underlying the present disclosure is to provide an improved filter device, in particular for the filtration of beer, as well as a corresponding method by which beer can be filtered in a simple and efficient as well as environmentally safe manner.
By the nonfiltrate to be filtered being introduced into the nonfiltrate chamber tangentially to the wall of the nonfiltrate chamber, a rotating flow can annually form along the wall and make the contents of the nonfiltrate chamber rotate over the bottom that is at least partially designed as a filter. Towards the center, the speed of this flow decreases, so that the nonfiltrate can there leave the nonfiltrate chamber again via the nonfiltrate outlet, resulting in a continuous flow through the nonfiltrate chamber.
The nonfiltrate supplied tangentially under pressure, preferably via a pump, is forced to form a helical circulating flow directed downwards, like in a hydrocyclone. By the throttle effect in the lower part of the nonfiltrate chamber, portions of the external swirl are constantly deflected to an internal turbulent flow directed upwards. The nonfiltrate flowing over the bottom passes through the filter or the filter sections, is thus filtered and can then leave the filter device.
Due to the centrifugal force in the nonfiltrate chamber, larger and heavier particles collect at the inner walls of the nonfiltrate chamber and sink downwards to the center of the bottom. Microfiltration is then accomplished via the filter or the filter sections embodied in the bottom of the nonfiltrate chamber. A compact filter design is thus formed that permits simple and efficient filtration. That means, only one filter device is required for coarse and fine filtration.
Advantageously, the nonfiltrate outlet is arranged essentially in the center of the upper side of the nonfiltrate chamber as here the nonfiltrate rises upwards due to the internal swirl.
Advantageously, the nonfiltrate outlet comprises an outlet pipe of which the cross-sectional area diminishes towards the top. By the diminution of the cross-section of the outlet pipe, the flow rate of the nonfiltrate is increased towards the top whereby the nonfiltrate can be efficiently removed.
Advantageously, the filter disk is a microfilter disk that filters out particles within a range of >10-1 to 10-2 μm, in particular within a range of >0.2 to 1.8 μm. Thus, the filter according to the disclosure can reliably filter out yeasts and solids.
Preferably, the microfilter is designed as microfilter disk and preferably formed of a disk or plate perforated by means of a laser. Such a plate has sufficient stability, can be easily fabricated and permits pore sizes within a μm range with at the same time large free screen surfaces.
Such a filter can be either embodied to be self-supporting or rest on a support, where the support can be embodied as backing fabric, in particular as metallic fabric or a wide-meshed grid extending three-dimensionally, where the grid openings of the support are essentially larger than the pore size of the filter to ensure optimal flow and stability.
The diameter of the nonfiltrate chamber can diminish towards the bottom, or else the bottom of the nonfiltrate chamber can be arched. The diameter of the filtrate chamber, too, can diminish towards the bottom, or the bottom can be arched.
Together, the nonfiltrate and filtrate chambers can form an essentially wok-like shape. If the diameter of the filtrate chamber slightly diminishes towards the bottom, there will be a throttle effect of the circulating flow that facilitates the upward flow in the center of the nonfiltrate chamber.
Advantageously, the nonfiltrate outlet is connected to a return conduit conducting the nonfiltrate in the circuit back to the filtrate chamber and/or to a buffer/feeder tank.
Thus, the nonfiltrate discharged from the nonfiltrate chamber can be again supplied to the filtration, where a continuous flow over the bottom, i.e. over the filter, is possible.
According to a preferred embodiment, the filtrate outlet comprises a circular conduit connected to the filtrate chamber via several openings. This permits a steady removal of the filtrate.
Furthermore, the filter device comprises means that vibrate the bottom preferably in a pulsed manner. The bottom or the filter, respectively, can be vibrated either during the complete filter procedure or else at intervals. The excitation prevents a clogging of the pores of the filter or of the surface of the filter.
Advantageously, the filter device comprises a movably rotating brush on the bottom of the nonfiltrate chamber for cleaning purposes. This can prevent the surface of the filter from clogging completely. The brush can also loosen deposits which can then be removed through the nonfiltrate outlet by a backwash procedure. The brush can be moved by a magnet passing outside, as in an aquarium, or by a drive shaft. The brush can also be driven by a magnet as in a magnetic levitation train.
According to a preferred embodiment, at least one opening is embodied in the bottom of the nonfiltrate chamber in which a corresponding filter disk is arranged. Such a filter bottom can be very easily prepared, and several small filter disks can be also integrated in the bottom. In particular if the bottom does not have a flat design, it is advantageous to arrange several filter disks with smaller dimensions in the bottom. A bottom embodied in this way also has a greater stability. Then, filter materials that cannot be fabricated with a large surface can be used.
According to a further preferred embodiment, the filtrate chamber is arranged underneath the nonfiltrate chamber and also extends laterally around the filtrate chamber. Such an arrangement is particularly space-saving and compact as here the nonfiltrate chamber can be arranged more or less in the filtrate chamber.
Advantageously, the walls of the nonfiltrate chamber are at least partially embodied as a bellow. This has the advantage that vibrations generated by the means that vibrate the bottom of the nonfiltrate chamber can be absorbed.
The means that vibrate the bottom of the nonfiltrate chamber can preferably comprise a vibrating shaft extending in a sleeve through the filtrate chamber and knocking on the bottom. The sleeve can be arranged at one end at the wall or the bottom of the nonfiltrate chamber, and at the other end at the wall or the bottom of the filtrate chamber and be at least in sections embodied as a bellow. This solution allows the vibrating shaft to vibrate the bottom of the nonfiltrate chamber without contacting the liquid in the nonfiltrate chamber. In the process, vibrations are efficiently absorbed by the bellow in the sleeve.
It is advantageous for the outlet pipe as well as the nonfiltrate inlet to be arranged to be height adjustable. Thus, the height of the outlet pipe as well as the height of the nonfiltrate inlet can be adjusted to a corresponding filtering process.
Advantageously, a pressure control valve is arranged in the filtrate outlet so that the pressure in the filtrate chamber can be adjusted.
Preferably, the pressure in the filtrate chamber and in the nonfiltrate chamber are kept above the saturated vapor pressure of CO2, so that no CO2 outgases. Here, the pressure must be adjusted such that the pressure in the nonfiltrate chamber is higher than the pressure in the filtrate chamber, so that the nonfiltrate can pass through the filter. For a sufficient rotating flow to form, the nonfiltrate is preferably introduced tangentially at a speed of 1 to 10 m/s, where in a feed conduit speeds of up to about 6 m/s prevail, and directly at the inlet into the nonfiltrate chamber, speeds of up to about 10 m/s occur.
It is advantageous to provide a filter system with several filter devices that are arranged in series or in parallel to each other to increase the filter capacity.
The present disclosure will be illustrated below in greater detail with reference to the following figures:
a shows a plan view onto a filter disk.
b shows the enlarged area A of
c shows an enlarged partial section along line I-I in
a shows an enlarged section of a filter 4.
b shows an enlarged section of a section along line A-A in
The nonfiltrate chamber comprises a round cross-sectional area, the diameter of the nonfiltrate chamber here being larger than its height. The bottom of the nonfiltrate chamber 2 is at least partially embodied as filter 4 and here comprises the filter disk 4. In the filter device 1, the bottom 14 separates the nonfiltrate chamber 2 from the filtrate chamber 3 arranged underneath the bottom 14, here the filter disk 4.
The nonfiltrate chamber 2 furthermore comprises a nonfiltrate outlet 5 starting at the upper side 2b of the nonfiltrate chamber 2. The nonfiltrate outlet 5 is arranged in the center of the upper side 2b. The nonfiltrate outlet 5 is embodied as outlet pipe the cross-sectional area of which diminishes from the upper side 2b of the nonfiltrate chamber towards the top. The nonfiltrate outlet 5 ends in a conduit 22 in which a control valve 8 is arranged, so that the flow of the nonfiltrate as well as the pressure in the nonfiltrate chamber can be adjusted or controlled. In this embodiment, the diameter of the nonfiltrate chamber diminishes downwards, i.e. in the direction of the filter disk 4. The diameter of the filtrate chamber 3, too, diminishes towards the bottom. The nonfiltrate chamber 2 and the filtrate chamber 3 can thus together have the shape, for example, of a wok.
The filtrate chamber 3 comprises at least one filtrate outlet 6 that is connected to the filtrate chamber 3 via at least one opening 16 to discharge the filtrate via a filtrate discharge 23. In the filtrate discharge 23, too, a control valve 9 is provided to adjust the flow of the filtrate whereby the pressure in the filtrate chamber can be adjusted or controlled, respectively.
In this embodiment, the height of the nonfiltrate chamber diminishes from the outer wall 2a towards the nonfiltrate outlet 5.
The filter disk 4 is preferably a microfilter disk that filters out particles of a size of >10-1 to 10-2 μm, advantageously particles of a size of >0.2 to 1.8 μm.
It is possible for the microfilter disk to comprise a photolithographically generated grid 10 as can be seen in particular in
a shows a plan view onto the circular filter disk 4,
According to a particularly preferred embodiment, the microfilter disk is formed of a disk or plate perforated by means of a laser, as can be taken in particular from
The filter disk 4 perforated by means of a laser as illustrated in connection with
The filter disk 4 can extend across the whole bottom 14 of the nonfiltrate chamber, as is represented in
To prevent a clogging of the filter disk 4, the filter 1 according to the disclosure preferably comprises means 25 to vibrate the filter disk 4. Preferably, the means 25 vibrate the filter disk 4 in a pulsed manner. Such means can comprise, for example, a vibrating head arranged at the outer wall of the filter, preferably at the same level as the filter disk 4, which transmits the vibrations to the filter disk 4. The filter 1 according to the disclosure can also comprise a mechanical vibrator that pushes directly or indirectly against the bottom or the filter 4 in a pulsed manner. Thus, fouling in the pores/channels and at the surface of the micro-screens can be prevented efficiently. Here, the filter can be vibrated during the complete filtration or else at intervals.
Below, the functional principle of the filter according to the disclosure will be illustrated more in detail. As is represented in
By the centrifugal force, larger and heavier particles of the nonfiltrate collect at the inner wall 2a of the nonfiltrate chamber. The discharged nonfiltrate flow U2, however, is also still loaded with particles and can be again supplied to the nonfiltrate chamber 2 or a buffer/feeder tank in the cycle via a return conduit 22. The speed of the nonfiltrate outlet 2 and the pressure in the nonfiltrate chamber can be adjusted by means of a control valve 8. The nonfiltrate rotating in the nonfiltrate chamber 4 over the bottom 14 passes transversely to the bottom through the filter disk 4 (or the filter disks 4a, b, c . . . n) downwards as is represented by the arrows F. The nonfiltrate is thus filtered through the filter disk.
Thus, during filtration, two effects are advantageously combined, namely the centrifugal separation as well as the microfiltration through the filter 4. The filtrate in the filtrate chamber 3 can be supplied to a filtrate discharge 23 via a corresponding filtrate outlet 6. The discharge speed of the filtrate as well as the pressure in the filtrate chamber 3 can also be adjusted by means of the control valve 9.
The pressure in the nonfiltrate chamber 2 and in the filtrate chamber 3 is adjusted such that it is above the saturated vapor pressure of CO2, so that no CO2 outgases during the filtration of beer. The pressure in the nonfiltrate chamber and in the filtrate chamber is adjusted by means of the nonfiltrate inlet 7 and the control valves 8 and 9 such that the pressure in the nonfiltrate chamber 2 is higher than the pressure in the filtrate chamber 3.
As can be taken from
The filter device moreover comprises a filtrate outlet 6 arranged in the bottom 13 of the filtrate chamber 3. Reference numeral 49 designates a vent of the filtrate chamber. The vent can be opened or closed by means of a non-depicted valve.
This filter device 1, too, comprises means 25 to vibrate the bottom 14 of the nonfiltrate chamber. The means 25 comprise the vibrating shaft 42 adjoining the bottom 14 and making it vibrate. The vibrating shaft 42 extends through the sleeve or the tube 43. The sleeve 43 is arranged at one end at the bottom of the nonfiltrate chamber 2 and at the other end at the bottom of the filtrate chamber 3. Thus, the vibrating shaft 25 can reach the bottom 14 without passing through the filtrate. The sleeve 43 is at least partially embodied as a bellow 44 that absorbs the vibrations. Thus, the vibrations are not or only slightly transmitted to the housing of the filtrate chamber 3. Similarly, the wall 2a of the nonfiltrate chamber 2 is also at least partially embodied as a bellow 40, so that the vibrations of the bottom 14 are not transmitted to the cover plate 46 and to the walls of the filtrate chamber 3.
In this embodiment, at least the area opposite to the sleeve 43 is not embodied as filter but is designed to be impermeable to the nonfiltrate, so that no filtrate can flow into the sleeve 43. The functional principle of the filter shown in
To increase the capacity of the filter, several filter units 1a, b, c, can be combined to form one unit 21, as represented in
The brush loosens the impurities on the filter disk 4. The brush 26 can be, for example, also rotatably mounted in the center of the filter disk 4.
In the embodiment shown in
The nonfiltrate flow that is removed via the nonfiltrate discharge 5 can be supported by a non-depicted pump. The filtrate outlet, too, can be supported by a non-depicted pump. On the side of the filtrate, a circulation of the filtrate along the bottom side of the bottom 14 can be generated by means of a suited flow generation. This provides a transmembrane drop of pressure from the bottom that is constant and well-balanced across the screen surface.
According to the present disclosure, two effects are combined, that is the effect of a hydrocyclone where due to the centrifugal force very large and heavy components are pressed against the wall of the nonfiltrate chamber, as well as the effect of a microfiltration through the filter disk(s) 4. Thus, according to the present disclosure, one does not need a combination of a coarse filter and a fine filter, but only one filter unit.
The present filter or the filter method according to the disclosure has been described in connection with the filtration of beer. This type of filter, however, is equally suited, for example, for the filtration in the pharmaceutical field, where e.g. tensides and spores are to be filtered out.
Number | Date | Country | Kind |
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07004460 | Mar 2007 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2008/000793 | 1/31/2008 | WO | 00 | 2/4/2010 |
Publishing Document | Publishing Date | Country | Kind |
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WO2008/107051 | 9/12/2008 | WO | A |
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Entry |
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Office Action for Korean Application No. 10-2009-7020491 mailed Jul. 20, 2011. |
Search Report for European Application No. PCT/EP2008/000793. |
Office Action for Japanese Application No. P2009-552082 Mailed Apr. 10, 2012. |
Number | Date | Country | |
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20100151100 A1 | Jun 2010 | US |