DE8713306U1 - Filter device - Google Patents

Description

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Dlpl.-Phys. Heinrich Selds · Patent Attorney · ülcrstadlef Höhe 15 · PO Box 5105 ■ 6200 Wiesbaden 1 · ^ (o 6121) 562022

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Description

The invention relates to a device for filtering liquids, in particular beverages such as beer, which contains a filter cake formed on a filter carrier, delimited on its filtrate side and on its circumference by the filter carrier and its border, which faces the unfiltrate space with its free surface.

Until recently, asbestos-containing precoat filter materials of various formulations were used to form the filter cake for filtering of this type. In order to avoid health risks, however, people have now switched to using filtering devices of this type with asbestos-free filter cakes, with the aim of achieving a comparable clarification efficiency to that achieved with asbestos-containing filter cakes. However, when using asbestos-free filter cakes in such filtering devices, the flow rate achievable with precoat filtration is low, and in any case considerably lower than when using asbestos-containing filter cakes.

Similar conditions also apply to the use of asbestos-containing and asbestos-free cardboard filter layers. The flow rate achievable with asbestos-free filter layers is still lower than the flow rate achievable with the use of asbestos-free filter cakes.

It is therefore the object of the invention to equip a device for filtering liquids, in particular beverages such as beer, with filter cakes for precoat filtration processes, which, while maintaining the same or achieving better clarification sharpness than that of the known asbestos-free precoat filter cakes and the asbestos-free filter layers in practical use, allow a significantly increased flow rate to be achieved, in particular also compared to the asbestos-free filter layers in practical use, and which are also suitable for filtration tasks in the

Dlpl.-Phye, Heinrich Seids « Patent Attorney . Bierstadter Höhe 15 . PO Box S1ÖS · 62ÖÖ Wiesbaden i -^ (&oacgr;&oacgr;&iacgr;&Zgr;&idiagr;) 56 20 22

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can be used.

Surprisingly, it has been shown according to the invention that this object is achieved by the filter cake, at least in the structure of its filter-active layer, having a framework of interlocking fiber particles of fibrillated polyolefin with inserted short fiber particles of ground cellulose and that filter-active particles absorbing pressure substances and/or microorganisms, in particular diatomaceous earth particles, are embedded in this framework, the ground cellulose and/or absorbing particles being at least partially equipped with a positive zeta potential. By using the device according to the invention with the novel filter cake, a considerably higher overall performance can be achieved in precoat filtration processes. This in turn leads to considerable cost reductions and less environmental pollution. The filter cake provided in the device according to the invention is characterized in that the pressure which is established during filtration over the filter cake in the filtration direction

2Q difference compared to previous values is significantly reduced, so that the precoat filtration can be carried out with considerably less pressure than before. Despite all this, the clarification effect or the clarification sharpness compared to that of known asbestos-free filter cakes is fully retained, with the germ retention and depyrogenation through adsorption being significantly improved. As a result, the filter device according to the invention can be used in practically all areas of application of precoat filtration, for example in

- clarifying and disinfecting beverage filtration,

- Filtration in chemistry e.g. filtration of particularly aggressive media,

- Filtration in pharmacy

- Filtration in pharmacy, e.g. separation of pyrogens, - Filtration in biology/medicine,

- Filtration in the cosmetic industry.

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Diph-Phye, Heinrich Selds · Patent Attorney > Dlerstadter Höhe IS · P.O. Box SIOS . 6200 Wiesbaden i '°g? (0 612&Idigr;) 56 20

In one embodiment of the invention, the filter cake additionally contains fibrillated pulp particles made of softwood and/or hardwood pulp as a fibrillation enhancer. The particles made of softwood pulp and/or hardwood pulp can be at least partially equipped with a positive zeta potential. In addition to significantly improved cohesion of the filter cake, such frame enhancers offer excellent properties for improving the flow of the filter cake during pressure shocks. The particles made of softwood pulp and/or hardwood pulp can be at least partially equipped with a positive zeta potential. This achieves significantly increased additional adsorptive separation of turbidity.

Within the scope of the invention, the diatomaceous earth can be provided in the form of annealed fine diatomaceous earth (particle size: 90% finer than 30μπα), annealed medium-fine diatomaceous earth (particle size: 90% finer than 4θμπα) and annealed coarse diatomaceous earth (particle size: 90% finer than 55μπα) and can be embedded in the framework of fibrillated polyolefin and, if necessary, fibrillate cellulose particles, whereby the diatomaceous earth particles can be partially equipped with a positive zeta potential.

As fibrillated polyolefin, it is recommended to use fibrillated polyethylene fastin for the framework. Within the scope of the invention, the filter cake can have a two-layer structure, namely with a protective layer lying on the filter carrier and a filter-active layer supported by the protective layer with a framework and embedded porous filter-active particles. The composition of the protective layer can provide 1 to 5 wt.% ground cellulose (latib wood), 1 to 5 wt.% annealed perlite and 2 to 10 wt.% annealed coarse diatomaceous earth.

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DipL-Phyi. HeinriA Seids · Patent Attorney . Bierstadter Höhe 15 . PO Box 5105 . 6200 Wiesbaden 1 · 'S* (0 6121) 56 20

The filter-active layer can contain 20 to 50% by weight of ground pulp (hardwood), 5 to 20% by weight of polyolefin fibrid, 5 to 30% by weight of annealed perlite, 0 to 10% by weight of annealed, medium-fine diatomaceous earth, 0 to 10% by weight of annealed, coarse diatomaceous earth, 10 to 30% by weight of unannealed, fine diatomaceous earth, 1 to 10% by weight of fibrillated softwood pulp and 1 to 10% by weight of fibrillated hardwood pulp.

Within the scope of the invention, the filter-active particles can have a different degree of modification with a positive zeta potential. Likewise or instead, the cellulose fibers can also have a different degree of modification with a positive zeta potential.

An embodiment of the invention is explained in more detail below with reference to the drawing. They show:

20 25 30

Figure 1 shows a filter device according to the invention in axial section;

Figure 2 shows reduced-size cellulose particles and diatomaceous earth particles provided in the filter cake according to the invention at 250x magnification;

Figure 3 shows a fibrillated polyethylene particle provided in the filter cake according to the invention at about 250x magnification;

Figure H shows the framework of the filter cake according to the invention with embedded adsorbent particles in approximately 1000-fold magnification and

Figure 5 comparative representations of the

it runs on different filter cakes*

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DIpL-Phye. Heinrich Seids . Patent Attorney · Bierstadter Höhe 15-P.O. Box 5105-6200 Wiesbaden 1 -'S* (06121) 562022

According to Figure 1, the filtering device 10 has a trub frame 11, an upper cover 12 and a lower cover 13 with an inlet 14 for the unfiltered material and an outlet 15 for the filtrate. The trub frames 11 contain filter supports 16 on each of which a filter cake 17 is formed. Each filter cake 17 is surrounded by a frame part 18 of the trub frame 11. It rests with its underside on the filter support 16 and is exposed with its upper side opposite the unfiltered material space 19 formed in the trub frame 11. A collecting and discharge device 20 for the filtrate is formed under the filter support 16 in the trub frame 11. In the example shown, the filter cake 17 is formed with two layers, namely a lower protective layer 21 lying on the filter carrier 16 and an upper filter-active layer 22 facing the unfiltered area, which in turn lies on the protective layer 21. The filter cake 17 can be constructed according to the following table:

component

proposed area

Percentage of filter cake in wt.%

Example I Example

1. Protective layer 21

a) ground cellulose (hardwood)

b) annealed perlite

c) annealed coarse

2.

1 - 5

1 - 5

diatomaceous earth 20 10 fi
22 lteractive layer 5 a) ground cellulose
loose (hardwood) 5 - 50 b) Polyethylene fibrid 0 - 20 c) annealed perlite 0, - 35 d) annealed, medium
fine diatomaceous earth - 10 e) annealed coarse gur 5-10

1.7

1.7 6. 4

40.0 5.2

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6.4 0.5

1.7

1.7 3.3

24.0 13.3 30.7

2.1

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f) unannealed fine girder 10-30

g) fibrillated needle

wood pulp

1 -

h) fibrillated foliage

wood pulp 1 28.5
1.9
1.3

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6.4 4.2

The above-mentioned components of the filter-active layer, with the exception of the polyethylene fibrid, are equipped with different modification levels with a positive zeta potential, occupancy level of choice between 0.5% and 40%.

&Iacgr;0 Tasks of the individual components of the filter-active layer 22

component

c'.) ground cellulose

b) Polyolefin fibrid (polyethylene fibrid)

c) annealed perlite

d) annealed medium-fine Gur

e) annealed coarse gur

f) unannealed fine girder

g) fibrillated softwood pulp

h) fibrillated hardwood pulp

Task

Loosening the cake to increase its shelf life

Reinforcing and stabilizing the cake (preventing unwinding and cracking, absorbing pressure surges, supporting structure for products a, c - f

like product a)

mechanical turbidity separation

mechanical separation of turbidity and adsorptive separation of turbidity

as e) and separation of micro-j organisms

as b) with additional adsorptive separation of turbidity

like G)

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Dipl.-Phye. Heinrich Seids - Patent Attorney · Bierstadter Höhe 15 - PO Box SlOS . 6200 Wiesbaden 1 - *£* (0 61.21) 56 2022

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Advantages of the filter cake according to the tables above:

compared to layer filters

compared to known diatomaceous earth precoat filters

a) Quantity

5 performance

b) Clarifying effect

c) Microb.
Security

10 d) Sensitivity to pressure surges

e) possible.
15 Current

up to 10-fold higher

even

same to better

relatively insensitive 6-fold

up to 3 times higher

significantly better (2-facl:

significantly better (keeps back other microorganisms besides yeast)

insensitive
(see picture 5!)

2-3 times higher

As the following application example shows, the filters according to the invention are far superior in their performance to both the comparable, asbestos-free layer filters used in practice and the asbestos-free precoat filters used to date:

Recommended performance of a sheet filter in the beer sector 150 l/m ² h

Precoat filter ² IOO l/m ² h

Filter according to above examples 1000 l/m ² h

Figure 2 shows, at 250-fold magnification, reduced-size cellulose particles 23 and diatomaceous earth particles 2H to be introduced into the filter-active layer 22 of the filter cake 17. Figure 3 shows, at 250-fold magnification, a polyethylene fibrid particle together with some diatomaceous earth particles 24. Figure U shows the framework 26 of the filter-active layer 22 of the filter cake 17 at 1000-fold magnification. In this framework 26, the ground cellulose particles 23 and the polyethylene fibrid particles 25 are matted and interlocked with one another. In this framework 26, made of cellulose particles 2'j and

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Dlpl.-Phyn. Heinrich Selds · Patent Attorney · Blerstadter Höhe 15 > PO Box 5105 · 6200 Wiesbaden 1

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The filter-active diatomaceous earth particles 24 are embedded in the polyethylene fibrid particles 25. As can be seen from Figure 4, these diatomaceous earth particles 21 are of different sizes, depending on the degree of fineness of the diatomaceous earth used. The figure also shows perlite particles 27 embedded in the framework 26, which are also intended as adsorbing particles. Some of the cellulose particles 23 and some of the silica

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Equipped with zeta potential, a filter cake 17 with a filter-active layer 22 constructed as shown in Figure 4 can also be used to filter out microorganisms and pyrogens from beverages, primarily beer.

Figure 5 shows the filtration process, in particular the turbidity found in the filtrate during the filtration process, when pressure surges occur during the filtration process. The left part of Figure 5 was taken with a filter cake made of pure diatomaceous earth. The right part of Figure 5 was taken with a filter cake that contained components with a positive zeta potential and above all fibrillated polyethylene fibers, together with shredded cellulose fibers, i.e. a filter cake according to the general composition and examples 1 and 2 in the table above. Filtration tests with pressure surges were carried out with these two types of filter cake. The filtration process with pressure surges can be seen from the two comparison diagrams in Figure 5. The right diagram in Figure 5 shows that the mechanical stabilization of the filter cake is significantly increased. In the event of pressure surges, significantly lower turbidity fluctuations (peaks) occur in a filter cake, the composition of which is shown in the table above.

Claims (1)

PATENT ATTORNEY DIPL.-PHYS. HEINRICH SEIDS 6200 Wiesbaden 1 · Bierstadter Höhe 15 · PO Box 5105 · Telephone (0 6121) 5620 22 Postgiro account Frankfurt/Main 1810 08-602 · Bank: Deutsche Bank 306 571 - Nass. Sparkasse 120 040 995 Wiesbaden, October 2, 1987 S 384 VNR 10 7565 S/lö Seitz-Filter-Werke Theo & Geo Seitz GmbH & Co. Planiger Strasse 137
6550 Bad Kreuznach, DE Filter device Protection claims 1.) A device for filtering liquids, in particular beverages such as beer, which contains a filter cake formed on a filter carrier, delimited on its filtrate side and on its circumference by the filter carrier and its border, which faces the unfiltered area with a free surface, characterized in that the filter cake (17) has, at least in the structure of its filter-active layer (22), a framework (26) of interlocking fibrid particles (25) of fibrillated polyolefin with inserted short fiber particles (24) of ground cellulose and that filter-active particles (24, 27) which absorb turbid substances and/or microorganisms, in particular diatomaceous earth particles (24), are embedded in this framework (26), the ground cellulose and/or absorbent particles being at least partially equipped with a positive zeta potential. M «ill I lltflllf It It 4* ti* « «III i * i * i * 4 < III j. y . - -
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2 2.) Device according to claim 1, characterized in that the filter cake (17) contains fibrillated cellulose 5 Particles of softwood and/or hardwood pulp as a frame amplifier. 3,) Device according to claim 2, characterized in that the particles consist of softwood pulp and/or Hardwood pulp at least partially with positive 10 are equipped with Zeta potential. 4.) Device according to one of claims 1 to 3, characterized characterized in that diatomaceous earth in the form of calcined fine diatomaceous earth (particle size: 90%<30 um), glowing microfine diatomaceous earth (particle size: 15 90% < 40μπα) and calcined coarse diatomaceous earth (particles size: 90% C 35μπα) into the framework (26) of fibrillated Polyolefin and possibly f!brillated cellulose particles is embedded, whereby the diatomaceous earth particles (24) partially equipped with positive zeta potential 20 are. 5.) Device according to one of claims 1 ^to 4, characterized characterized in that fibrillated polyetr.ylene fibers (25) is provided for the scaffolding (26). 6.) Device according to one of claims 1 to 5, 25 characterized by two-layer structure of the filter cake (17) with on 'Je-rn FiI.erträger (16) lying Protective layer (21) and from the protective layer supported filter-active layer (22) with framework (26) and embedded porous filter-active particles (24, " 27). i S
e I Uli I < I i &igr;&igr;&igr; &igr; ti &bull; 1 Dlpl.-Phy«, Heinrich Selds · Patent Attorney · Dlcrstadtcr Hülle 15 > PO Box 5lO5 ■ 6200 Wiesbaden 1 >"g? (06121) 56 2022 7«) Device according to claim 6, characterized by a composition of the protective layer (21) with 1 to 5 wt.% ground sulfur (hardwood), 1 to 5 wt.% annealed perlite and 2 to 10 wt.% annealed coarse diatomaceous earth, Device according to one of claims 1 to 7» characterized by a composition of the filter-active layer (22) with 20 to 50 wt.% ground pulp (hardwood), 5 to 20 wt.% polyolefin fibrid, 5 to 30 wt.% annealed perlite, 0 to 10 wt.% annealed, medium-fine diatomaceous earth, 0.5 to 10 wt.% annealed, coarse diatomaceous earth, 10 to 3% wt.% unannealed, fine diatomaceous earth, 1 to 10 wt.% fibrillated softwood pulp and 1 to 10 wt.% fibrillated hardwood pulp. 9.) Device according to one of claims 1 to 8, characterized in that the filter-active particles (24, 27) have a degree of occupancy with positive zeta potential between about 0.5% and 80%. 10.) Device according to one of claims 1 to 9, characterized in that the cellulose fibers have a degree of occupancy with positive zeta potential between about 0.5% and 40%.