EP0999995A1

EP0999995A1 - Flow-through beaker which can be filled with a granulate

Info

Publication number: EP0999995A1
Application number: EP99930987A
Authority: EP
Inventors: Detlev Weyrauch
Original assignee: Brita SE
Current assignee: Brita SE
Priority date: 1998-03-28
Filing date: 1999-03-24
Publication date: 2000-05-17
Also published as: US6012232A; DE19814008A1; AU4767599A; WO1999051527A1

Abstract

The invention relates to a flow-through beaker which can be filled with a granulate and through which a liquid to be treated can flow. The flow-through beaker has side walls at the ends of which screens are fitted, said screens helping to ensure that the liquid can flow through the granulate inside the flow-through beaker and that the granulate is essentially retained. The aim of the invention is to improve a flow-through beaker of this type so that the in-flowing liquid and at the same time, any escaping gases meet with as little resistance as possible. To this end, at least one screen has a textile fabric (23) wherein plastic fibres (24, 25) of at least two different types are interconnected in order to form a hybrid material, one of the types of plastic fibre (24) containing hydrophilic components and the other type (25) containing hydrophobic components.

Description

Flow cup fillable with granulate

The invention relates to a flow cup which can be filled with a granulate and can be flowed through by a liquid to be treated, and has side walls and sieves attached to the ends thereof, with the aid of which the granulate can be flowed through inside the flow cup and kept essentially captive.

For filtering, cleaning or otherwise treating liquids, filter devices are known which, as flow cups, have a specific shape of a cartridge which is filled with granular ion exchanger and / or activated carbon. The water to be filtered is filled in through a sieve cover and leaves the filter cup through its sieve at the bottom. The known filter device is inserted into a funnel of a water purification device provided for this purpose, which is placed on a collecting or collecting container for filtered liquid and is preferably closed at the top with a removable cover. In this way, tap water for tea preparation or the like can be improved.

The known filter cups have slotted plastic fields in the lid and / or bottom as sieves. These slots retain the granular filter material in the filter cup. In order to offer the largest possible surface area of filter material to the flowing liquid or to force the liquid to undergo the most intensive and extensive adsorption activity, filter particles of small size are used. Particles of around 200 μm and smaller occur in the filter material. The active surface offered to the continuous liquid to be filtered is therefore pleasantly large. However, this advantage is associated with the disadvantage that some of these smallest granulate particles pass through the inlet openings in the lid and the outlet openings in the bottom. These particles floating in the cleaned liquid are not desired by the user, but are disturbing.

Injection molding, however, should not be less than the size of a retaining slot in the lid and / or bottom, ie in the sieve in question. Activated carbon particles in particular can have a platelet shape, the minimum dimension of which can reach 250 μm or less, so that precisely these particles, which are visually visible to the end user, can pass through the inlet and outlet slots. In terms of injection molding, however, the slot width of approximately 200 μm is the lower limit and cannot be undercut. - 2 -

Therefore, it has already started to use textile fabrics in the form of nonwovens as sieves at the top and / or bottom of a filter cup. Alternatively, sieve fabrics with a small pore size of, for example, 200 μm have been injection molded from plastic. In this, however, there have been difficulties with the flow of the liquid through this type of sieve fabric, for reasons that cannot be explained so far, even if it was only water. The surface tension of a liquid is known, which has a negative effect, particularly in the case of small sieve pores, in that the liquid is considerably prevented from flowing through and in some cases even blocked. Attempts to use hydrophilized plastic fabrics for the screens have not led to the desired success.

For this reason, a screen mesh has been developed that is curved in itself. This made it possible to fill the inside volume of a flow cup up to about 86% to 95% with the granulate, and nevertheless a good flow of the liquid is achieved with a favorable retention capacity of the granulate.

The simplest possible shape of a sieve can contribute to simplifying production, assembly and also use, the flow capacity being able to be improved even with a very small pore size which is still smaller than the known sieves.

When preparing the invention, it was found that a sieve fabric with very small pores can be produced, so that the particle leakage can be greatly reduced. If one also selects hydrophilic plastic fibers as the plastic material, then one obtains a very good flow through for liquids, in particular for water. It has been found, however, disadvantageously that lamellae of water form in the meshes or pores of such screen fabrics made of hydrophilic synthetic fibers and seal the fabric like a skin for an air flow. In practice, a good cleaning effect of a flow cup of the known type is associated with rising gases, so that at least the inlet-side sieve should have a good ventilation function. A hydrophilic fabric is unsuitable for such a ventilation function.

Now, however, there are hydrophobic synthetic fibers from which sieves of the desired type could be made. Even with small pore sizes, the lamellae described do not form due to the low surface tension. Experiments with water have shown that, on the contrary, the water contracts to form a drop of water on the surface of a hydrophobic fabric. However, the throughflow of the - 3 -

Sieves prevented for water.

Hybrid composite materials are already known, but they are used to improve the mechanical properties of the composite materials, for example for the design of surfaces in shipbuilding, surfboards or Formula 1 racing cars.

The invention has for its object to provide a flow cup of the type mentioned, in which as little resistance as possible to improve the inflowing liquid and at the same time outflowing gases is opposed. Similar conditions may also be desired on the downstream side.

This object is achieved according to the invention in that at least one sieve has a textile fabric in which plastic fibers of at least two different types are connected to form a hybrid, one type of plastic fiber containing hydrophilic components and the other type of plastic fiber containing hydryphobic components. It is particularly important to provide the textile fabric for the sieve on the inflow side, and the desired effect is achieved by the measure according to the invention when at least part of the sieve is equipped with a textile fabric according to the invention. "Textile" in connection with the flat structure means threads or yarns made of different materials. In this sense, textile also includes plastic threads or plastic fibers. These textile fabrics can be, for example, a nonwoven fabric, knitted fabric or also fabric.

The special feature of the invention is that you have a first type of plastic fiber with hydrophilic properties and a second type of plastic fiber with hydrophobic components. For the purposes of the invention, plastic fibers are understood to mean fibers, yarns or threads which have plastic. It can be made entirely or partly of plastic fibers. What is important is their outward-looking property, which is hydrophilic or hydrophobic. A hybrid is formed by connecting the plastic fibers according to the invention to one another.

Hybrids are already known in connection with composite materials. There, hybrids are created by embedding two or more fibers in a matrix. In the known composite materials, such as those used in shipbuilding, hybrids are understood as alloys in metallurgy. The main goal is to optimize the material (the hybrid or the alloy) so that the material meets the specific requirements in terms of performance and costs - 4 -

enough. In the known case, emphasis was placed on strength, rigidity, impact strength and other, mostly mechanical properties.

According to the invention, a hybrid is a textile fabric in which both the hydrophilic property and the hydrophobic property emerge simultaneously and / or next to one another. This surprisingly achieves that liquid entering the flow-through cup is well let through, because the liquid finds enough plastic fiber with hydrophilic properties, while at the same time rising and flowing gases, for example air, find enough hydrophobic plastic fiber.

In an advantageous further development of the invention, the textile fabric of the sieve is a hybrid fabric composed of hydrophilic and hydrophobic fibers. It is true that nonwovens can be used as textile fabrics, in which the cohesion does not come about by interweaving warp and weft, but rather by the plastic fibers' own adhesion or by the same preparation obtained. It is true that textile fabrics made by knitting and knitting can also be used in the sense of the invention. However, a fabric is particularly cheap. Such textile fabrics are expediently produced by crossing the warp and weft threads at right angles according to the rules of weaving. As is well known, there are many different types of weave that can be used to produce a hybrid fabric for the sieve.

According to the invention, it is particularly advantageous if the hybrid fabric has pure hydrophilic and pure hydrophobic areas. The liquid to be cleaned or filtered then not only flows through the sieve areas with textile fabrics past a few hydrophobic or hydrophilic synthetic threads or fibers, but larger hydrophilic or hydrophobic areas are provided as desired. Such areas can be of the order of magnitude of 1 mm to 1 mm and up to 40 mm to 40 mm. There are types of weave in which the fabric is subdivided like a checkerboard into pure hydrophilic, pure hydrophobic and mixed fields, if one divides the warp and weft threads accordingly.

According to the invention, the plastic of the hydrophilic fiber expediently contains polyester (PES) or polyamide (PA) and the plastic of the hydrophobic fiber contains polypropylene (PP) or polyethylene (PE). It is particularly preferred if the respective fiber consists of the plastic mentioned. Favorable tests were carried out with hydrophilic polyester threads and hydrophobic polypropylene threads. - 5 -

However, according to a further teaching according to the invention, it can also be provided that the hydrophilic fiber consists of a hydrophilized plastic and the hydrophobic fiber consists of a hydrophobized plastic.

The hydrophilic part of the molecule shows a pronounced interaction with polar solvents, especially with water. Typical hydrophilic groups are carboxylate, sulfate and sulfonate and optionally substituted ammonium functions or polyester chains. Hydrophilizing is a textile chemical measure to increase the water affinity or the absorbency and the moisture transport capacity of synthetic fibers. The hydrophilization is carried out with the aid of hydrophilizing agents which are known per se, for example ethoxylation products.

Typical hydrophobic groups are, for example, long-chain or aromatic hydrocarbon radicals, which can also be perfluorinated. Hydrophobing agents used for waterproofing cover, for example, textiles or leather with a thin layer of hydrophobic groups, such as longer alkyl chains. Water droplets roll off hydrophobized materials without wetting them.

It is also expedient according to the invention if the textile fabric of the sieve is connected to support ribs by injection molding, welding, gluing or the like. In this way, the textile fabric of the sieve with the properties intended according to the invention can be fixedly or releasably attached to the bottom or lid area of a flow cup and mechanically well supported by intermediate ribs. Arched configurations of a sieve are also possible.

It is advantageous if, according to the invention, the size of the pores of the textile fabric is 10 μm to 200 μm and preferably 20 μm to 100 μm. If a sieve is equipped with such a textile fabric on a flow-through cup, the particle leakage of fine-grained granules can be prevented without problems. At the same time, the textile fabric in the lid of the flow cup, for example a filter cartridge, offers as little resistance as possible to the inflowing water, but also has sufficient gas permeability for the necessary venting of outflowing gases. This is achieved by using the hydrophilic and, in addition, the hydrophobic areas, which are arranged unevenly or evenly distributed over the surface of the screen.

For example, threads made of polyester or polyamide can be used as hydrophilic fibers or threads - 6 -

use. Textile fabrics made from these fibers have a very good flow through for liquids, especially for water.

Polypropylene or polyethylene can be used as the hydrophobic threads or fibers. In areas with pure hydrophobic threads or fibers, in particular with hydrophobic fabrics, lamellae of liquid or water cannot form due to the low surface tension. For example, the water on the surface of such a sheet contracts to form spherical drops of water. It does no harm if the flowability for liquid, in particular water, is more or less prevented because the flow then takes place through the neighboring hydrophilic areas.

It is particularly advantageous if the plastic fibers or plastic threads consist of a uniform material, that is to say in one case of hydrophilic plastic alone and in the other case of hydrophobic plastic alone. The thread itself therefore does not contain plastic mixtures. In particular in the case of the fabric as a textile fabric, it is possible in this way to produce pure hydrophilic areas and also pure hydrophobic areas. In the case of a canvas fabric, for example, weaving technology cannot avoid a mixed zone between pure hydrophilic zones and pure hydrophobic zones arranged next to it.

Further advantages, features and possible uses of the present invention result from the following description of preferred exemplary embodiments in conjunction with the attached drawings. Show it:

FIG. 1 shows a cross-sectional view through a flow cup of a special embodiment according to the invention,

Figure 2 is a plan view of the curved sieve at the upper end of the inflow

Flow cup, seen from inside the cup,

FIG. 3 shows a cross-sectional view through the cover with the strainer on the inflow side attached thereto,

Figure 4 is a schematic representation of a hybrid fabric in the form of a canvas fabric

FIG. 5 shows a textile fabric with a checkerboard arrangement of hydrophilic, hydrophobic and mixed areas. - 7 -

The flow cup shown overall in cross section in FIG. 1 consists as a lower part of a cup 2 filled with granular filter material 1, the bottom 3 of which has outlet openings 4 with sieving devices (not shown) and is pulled up obliquely inwards at one point to form a ventilation notch 5. The side walls of the flow cup 2 end at the top in a sealing flange 6, which includes an imaginary, horizontal plane; the entire device also consists of a cover, generally designated 7, whose outer, lower flange 8 terminates with the same imaginary horizontal plane and is inserted in the sealing flange in such a way that a liquid-tight connection, for example welding, is easily possible. In addition to the flow cup 2 and the lid 7 placed thereon, the filter device has, as a third part, a sieve 9 on the inflow side, which has a retaining ring 10, which also includes the imaginary horizontal plane. As a result, the retaining ring 10 of the sieve 9 fits the lid 7 and the flow cup 2 in such a way that the three parts can be connected to one another in a liquid-tight manner in the region of the common connection plane, for example welded.

In addition, one can see stacking ribs 1 1, which extend approximately over half the height of the flow cup 2 from the bottom 3 upwards and are evenly distributed on the inside of the side walls, for example three of them. The finished flow cup 2 are placed on these stacking ribs 1 1 after plugging into one another for storage. Before assembly of the entire filter device, the empty flow cups 2 can therefore be stored in a stack in a stack.

The lid 7 consists of a lower outer part 1 2 next to the outer flange 8, in the surface of which there are inlet openings 13 for the liquid to be filtered. The respective vertical section through the cover 7 according to FIGS. 1 and 3 is such that it runs straight through an inlet opening 13 on the right side.

This outer part 12 of the lid 7 narrows upwards and ends in a gripping part 14 with a gripping trough 15 and with ventilation slots and some ventilation holes 17 arranged above it, through which air rising from below can escape to the outside of the filter device during operation. Finally, 7 can be seen on the inner surface of the cover 7 holding ribs 18, through which a bearing surface for the screen 9 is created in the cover 7.

The screen 9, which is mainly visible in the middle in the plan view of FIG. 3 from below in the direction of arrow A, consists of a spherical cap-shaped textile fabric 1 9, which - 8th -

is indicated by oblique hatching and is shown enlarged in FIG. 5 and even further enlarged in the detail in FIG. 4. The entire hatched area of the sieve 9 represents the protruding, in this case curved sheet 1 9 in the direction of the filter material 1, which is injected into the flat retaining ring 10. Ribs 20 with a centrally arranged annular rib 21 are also molded onto the textile fabric 1 9 and hold it dimensionally stable as a spherical cap.

On the side facing away from the curvature towards the flow cup 2, that is to say in FIGS. 1 and 3, which also represent the operating form, upward, four position knobs 22 are attached to the retaining ring 10, which protrude evenly around the circumference and project upwards so that they hit the bearing surface of the four retaining ribs 1 8 in the cover 7 when the retaining ring 10 is in the correct position. This is shown in the figures.

After completion of the flow cup 2, the lid 7 and the sieve 9, the latter can be brought into the position shown in Figure 3, in which the positioning knobs 22 are brought into contact with the retaining ribs 18 and the retaining ring 10 is located on the peripheral flange 8 of the lid 7 . In this arrangement, the screen 9 is welded to the cover 7 in a liquid-tight manner.

The flow cup 2 is filled with filter material 1, after which the cover 7 is brought into the position shown in FIG. 1 and the flange 8 is welded to the sealing flange 6 in a liquid-tight manner.

The filter device of FIG. 1 produced in this way can then be inserted into a filter device (not shown) and used by the end user. The liquid poured in above, preferably water to be filtered, enters through the liquid inlet openings 13 of the cover 7, also referred to as sieve slots, flows through the sieve 9, the filter material 1 and leaves the flow cup 2 through the outlet opening 4, which passes through a filter on the bottom through the filter material 1 also holds back.

If one looks at a section from the circular disk of FIG. 2 provided with oblique hatching, that is to say a part of a textile fabric 19 that has broken away, the ribs 20 and the annular rib 21 being omitted, then one sees the textile fabric 19 of the sieve 9, which in this embodiment there is a hybrid fabric 23 with hydrophilic fibers 24 and hydrophobic fibers 25. Where hydrophilic fibers 24 cross at 90 ° with hydrophilic fibers 24, there are pure hydrophilic regions 27. Where the one in FIG. 4 knows - 9 -

cross hydrophobic fibers 25 shown with other hydrophobic fibers 25 running perpendicular to it, pure hydrophobic areas 26 are obtained. When looking at a larger area according to FIG. 5, it can be seen that the areas represented by white rectangles represent these hydrophobic areas 26. Accordingly, the black rectangles are the hydrophilic areas. In between there are the mixed areas 28, which cannot be avoided with a canvas fabric made of two types of threads or fibers 24, 25.

In the enlarged representation of the hybrid fabric 23 of FIG. 4, the pores 29 can also be seen, the size of which in the example shown is 30 μm to 30 μm.

It goes without saying that the hybrid fabrics 23 with support ribs 20, 21 shown in FIGS. 4 and 5 can be produced as a one-piece screen 9 corresponding to the hatched area in FIG. 2.

- 10 -

Reference list

1 filter material

2 flow cups

3 cup bases

4 outlet openings

5 vent notch

6 sealing flange

7 lids

8 lower flange

9 sieve

10 retaining ring

1 1 stacking ribs

12 outer part of the cover

13 entry openings

14 gripping part

1 5 gripping recess

1 6

1 7 ventilation holes

1 8 retaining ribs

19 textile fabrics

20 ribs

21 ring rib

22 position neps

23 Habrid fabrics

24 hydrophilic fibers

25 hydrophobic fibers

26 hydrophobic areas

27 hydrophilic areas

28 mixed areas 29 pores

Claims

- 1 1 -patent claims

1 . With a granulate (1) fillable and flowable from a liquid to be treated flow cup (2) with side walls and attached to the ends of the same sieves (9), with the aid of which the granulate (1) inside the flow cup (2) can be flowed through and essentially is held captive, characterized in that at least one sieve (9) has a textile fabric (19) in which plastic fibers (24, 25) of at least two different types are connected to form a hybrid, one type of plastic fiber (24 ) contains hydrophilic and the other type of plastic fiber (25) hydrophobic components.

2. Flow cup according to claim 1, characterized in that the textile fabric (1 9) of the sieve (9) is a hybrid fabric (23) composed of hydrophilic and hydrophobic fibers (24, 25).

3. Flow cup according to claim 1 or 2, characterized in that the hybrid fabric (23) has pure hydrophilic and pure hydrophobic areas (27, 26).

4. Flow cup according to one of claims 1 to 3, characterized in that the plastic of the hydrophilic fiber (24) polyester (PES) or polyamide (PA) and the plastic of the hydrophobic fiber (25) polypropylene (PP) or polyethylene (PE) contains.

5. Flow cup according to one of claims 1 to 4, characterized in that the hydrophilic fibers (24) consists of a hydrophilized plastic and the hydrophobic fiber (25) consists of a hydrophobized plastic.

6. Flow cup according to one of claims 1 to 5, characterized in that the textile fabric (1 9) of the sieve (9) is connected by injection molding, welding, gluing or the like with supporting ribs (20, 21).

7. Flow cup according to one of claims 1 to 6, characterized in that the size of the pores (29) of the textile fabric (19) is 10 microns to 200 microns and preferably 20 microns to 100 microns.