DE2931762A1 - EDGE-SEALED, MULTILAYER FILTER PLATE - Google Patents

Description

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BAYER AKTIENGESELLSCHAFT 5090 Leverkusen, Bayerwerk

Central area ^{Hö / bc / c} 3. AUQ. 1979 patents, trademarks and licenses

Edge-sealed, multi-layer filter plate

The invention relates to a multi-layer filter plate in which a support layer on both sides with a filtration or permeation-active layer is covered, in each support layer the permeate in one or more Cavities can be collected, the cavities in the case of adjoining filter plates in one another Are connected and a possibility for releasing the permeate is provided.

In the case of filter plates, the filtration layer facing the medium to be filtered often lies on top of one porous support layer. The efficiency can be increased if the porous support layer on both sides with the Filtration layer is covered, the plate on both sides is flowed around by the medium to be filtered, which is mostly under pressure, and the filtrate from the Inside the filter plate, i.e. from the porous support layer, for example through drainage openings on the Plate level or in the edge zone is pulled off. Such multi-layer filter plates become filter cartridges or filter modules for simple filtrations, however also manufactured for ultrafiltration or reverse osmosis.

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The edge zones are critical in such devices at the end faces of the multilayer filter plates, as there is contamination from outside the filter plate can penetrate between the filter layer and the support layer and thus into the permeate.

When the edge zones are pressed together in a pressure-tight manner with the aim of making the filter layer liquid-tight and pressure-resistant to seal against the supporting layer becomes all-round Prevents washing around the filter plate. Welding or gluing of the filter layers encompassing the support layer succeeds only very imperfectly and only with a few filter sheet materials; it's special problematic if the filter layer is, for example, a glycerinized reverse osmosis membrane.

When encapsulating with thermoplastics, the temperature stress the filter layer, especially in the case of carrier membranes based on polyolefin carriers, is damaged and thermoplastics adhere to many, In particular, there is no preserved filter layers, so that no pressure-tight seal is achieved.

It has now been found that these difficulties the poor adhesion of plastics to membrane materials with simultaneous temperature sensitivity the membrane structure can be circumvented surprisingly can if the edge zones of the filter plates with cold hardening reaction resins are coated. Cold-curing polyurethane reaction resins are very particularly suitable.

Also filter plates, their covering filter layers glycerinized ^ asymmetric reverse osmosis membranes

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exist, get an excellent pressure-tight sealing edge zone reinforcement. It would actually be too had been expected that precisely the preservative would form a suitable pressure-resistant connection between the edge zone reinforcement material and prevent membrane material from exudation and reaction disorders. as Cold-curing reaction resins are, in addition to polyester and epoxy resins, especially polyurethane reaction resins suitable. In the case of polyurethane resins, the mechanical properties can easily be varied within a particular range will; cold-curing types from elastic to hard are known; they can be removed from the mold in seconds will; the viscosity can be adjusted so that it does not flow around the end faces of the filter plate but penetration into this is achieved; Because of the unexpectedly good adhesion, it is also pressure-resistant Sealing of glycerinized filter membranes possible.

The edge zone reinforcement of a multi-layer filter plate makes it possible to compress filtration modules build up when the gas or liquid supply and discharge openings on the filter plates and the bores for producing the plate stacks are matched to one another.

A filter plate according to the invention is shown in the drawing and described in more detail below.

Show it:

1 shows a cross section through a multilayer filter plate;

2 shows a round filter plate with a central filtrate discharge opening r

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3 shows a plate from a module unit.

On both sides of the porous support layer 1, the one on one side is held on the left side, the filter layer 2 lies on. The edge 3 of the filter plate is with encapsulated in contact with a reaction resin and cured. The permeate exits at 4 on the side.

2 shows a plan view of a filter plate 5 with a central permeate discharge 6. The edge 7 is in turn encapsulated in a contacting manner with a reaction resin. If necessary, the edge of the filtrate discharge opening can also be used 6 be coated with a reaction resin.

The filter plates 8 shown in Fig. 3 can be easily combined to form a module. in the Bores for tie rods are provided for contacting overmolded edge region 9. There are two on this record Permeate discharge openings 11 available. Located in area 12 the solution supply, in area 13 the solution discharge.

With an arrangement of the filter plates according to FIG. 3, the edge zone reinforcement can also act as a spacer with take over. In most cases it is sufficient if the gaps are 1 to 5 mm covered (Area 3 in Fig. 1); but if, for example, as in Fig. 3, the holes for the tie rods are in the edge zone Area, you will choose a larger width (area 9 in Fig. 3).

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Commercially available systems with elastic, semi-hard or preferably hard character. Cold-curing types on a multi-component basis are preferred. Such Polyurethane reaction resins generally consist of one or more polyols with 2 or more OH groups per molecule as one and one or more polyisocyanates as the other component. Often times will also catalysts, mostly basic compounds or metal salts and stabilizers such as zeolites, Phenols, anti-aging agents and fillers are also used. :

The polyols are polyester polyols, preferably neutral ones or basic polyether polyols, as they are according to the prior art the technology by the addition of, for example, ethylene oxide and / or propylene oxide are obtainable on alcohols and amines and have OH numbers of about 20 to 600, preferably around 400, have. Preferred polyisocyanates are aromatic types, in particular those which be produced according to the prior art as a technical mixture of aniline-formaldehyde condensates.

In the case of a filter plate construction, for example, the porous support plate consists of a glass fabric / glass fleece combination (0.9 mm thick) on which a reverse osmosis membrane supported on a polyethylene fleece on both sides based on polyaramid, which is preserved with glycerine, is applied. The thickness of this support membrane is approx. 0.3 mm. The diameter of the plate

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■ - is 6 cm. The active membrane surface faces outwards. Such a combination of panels is placed in a mold in which the edge zone reinforcement is virtually unpressurized can be made by pouring or flowing around with the polyurethane resin. In order to prevent the polyurethane reaction resin from penetrating To avoid getting into the porous support plate, the face may be filled with a spatula. The edge of the filter plate is molded with a fast-reacting PUR potting compound with a stable contour.

If the PU system VP PU 1146 / Desmodur 44 V10 is used B ^ from Bayer AG, is obtained after curing at room temperature a surface-hard, non-foamed molding compound with a bulk density between 1.0 and 1.2 kg / dm.

The gel time is around 15, the demolding time between 25 and 600 seconds. The mold temperature is between 20 and 60 ° C. Mixture, dosage and entry of the PUR are made with known piston dispensing machines.

For the overmoulding of the filter plates, a plate is tool used that has a 2- or 3-plate structure may have. With a 2-plate tool, half the article thickness is milled into the plates. the Cover plate contains a film gate and rod drive. The base plate has guide pins that both Center the inserts and the cover plate when the mold is closed. With 3-plate tools are Base and cover plate are plane-parallel and do not contain any cavities. A third interposed plate with its mask-like design determines the geometry

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drive of the molded part. Guide bolts in the base plate accommodate intermediate / cover plates and inserts and center this.

The first punched TrMger membrane, the porous GRP support plate, is threaded onto the guide bolts of the base plate and the second support membrane. After closing the mold, the machine doses a built-in one Mix head the reaction mixture. Afterwards, all that is required of the demolded articles is to break off the film. or bar cut necessary. For example, a circular filter plate with a circumferential Edge zone reinforcement made of hard polyurethane resin, which is completely flat. In an analogous way, rectangular » the shape of circular segments having, part circular or other outlines having filter plates with reinforced edge zones can be obtained.

In the center of the plate there is a prefabricated one Permeate discharge hole. This is now connected to a test apparatus in which the edge zone armored Filter plate with an aqueous dye solution, e.g. 0.05% aqueous fuchsine solution, can be applied under different pressures. That The pertneat that runs out is fabless, i.e. the membrane filter plate works flawlessly. The edge zone reinforcement can withstand a pressure of at least 50 bar.

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Claims (2)

Claims 1) Multi-layer filter plate with a support layer is covered on both sides with a filtration or permeation-active layer, in each Support layer, the permeate can be collected in one or more cavities, the cavities in the case of adjacent filter plates are connected to each other and one possibility is provided for the release of the permeate, characterized in that the edge zones of the filter plates are sealed with cold-curing reactive resins. 2) Multi-layer filter plate according to claim 1, characterized characterized in that the reaction resin is a polyurethane reaction resin with cold-curing properties is used. Le A T »754 130008/0451 INSPECTED