Water filter

Abstract

The invention relates to a water filter (1) comprising: a housing (2); an inlet (4) designed to conduct unfiltered raw water into the housing; a filter surface comprising multiple very small filter openings; and an outlet (5) for water designed to conduct filtered water out of the housing (2), wherein the filter surface is located between the inlet (4) and the outlet (5) in such a way that the water flowing from the inlet (4) to the outlet (5) flows through the filter surface. According to the invention, the housing (2) is flexible in such a way that the water filter (1) can be deformed between the inlet (4) and the outlet (5) at a bending angle of at least 45°, wherein the filter surface is formed by multiple hollow fibers (14), the walls of which comprise the filter openings.

Description

[0001] water filter

[0002] Description:

[0003] The invention relates to a water filter according to the preamble of claim 1.

[0004] Water filters are known in practice in a variety of designs. They are used to treat unfiltered water, known as raw water, by removing contaminants and microbes from the water, so that the filtered water is pure and can be used as domestic or drinking water. Raw water treatment is known in practice, in which domestic or drinking water is obtained through condensation or other processes.Furthermore, it is known in practice to obtain industrial or drinking water using reverse osmosis. This involves pressing raw water under pressure against a membrane. Due to the membrane's material properties, which lack pores, certain portions of the raw water pass through the membrane and can be used as industrial or drinking water, while another portion of the raw water, in which the undesirable components of the raw water have accumulated, is discarded as concentrate. Finally, the extraction of industrial or drinking water using ultrafiltration is known in practice. This has the advantage of making virtually the entire amount of the supplied raw water available as industrial or drinking water, because only the undesirable components are retained and discarded.Furthermore, the function of this filter, known as ultrafiltration, can be ensured with very low pressure because the raw water does not have to diffuse through the material of the filter surface, also known as the ultrafiltration membrane, but rather the filter surface has a large number of tiny filter openings with a pore size that can be between 10 and 200 nm and, for example, in the range of 20 nm. Therefore, no significant equipment is required to operate ultrafiltration. For example, ultrafiltration can be operated without a pump by simply using a small difference in height of, for example, 1 m between a raw water reservoir and the lower water reservoir to ensure flow through the ultrafiltration membrane arranged between these two reservoirs.Ultrafiltration causes a correspondingly low pressure loss in water treatment plants, so that it is also well suited for use in systems with low pump capacity.

[0005] A generic water filter comprises a housing in which the ultrafiltration membrane is arranged as the filter surface. The raw water enters the housing through an inlet and thus to one side—the raw water side—of the filter surface. After the water has passed through the filter surface and reached the clean water side of the filter surface, it exits the housing through an outlet provided by the housing.

[0006] In the field of filtration technology, it is common practice for the housings containing the respective filter surfaces to be approximately spherical or cylindrical. This applies to well-known water filters that operate according to the principle of reverse osmosis or ultrafiltration. Depending on the dimensions of the housing, installing the water filter can be difficult. For example, in recreational vehicles such as mobile homes, yachts, or boats, in order to provide as much space as possible for people to stay in, technical components are often installed in spaces within the vehicle that are already narrow or low and therefore unusable as a living area. For the technical components, this means that they are often difficult to access and must also be arranged close together, which further impairs their accessibility.

[0007] Water treatment systems always pose the problem of recontamination, as germs can enter the water pipes, for example, from the supply lines or storage tanks. Water treatment systems that have a water reservoir, as is the case with the recreational vehicles mentioned above, can also pose the problem of germs entering through a ventilation opening in the water reservoir. During extended periods of non-use, as cannot be ruled out with recreational vehicles, germs that have entered the water treatment system can multiply to an undesirable extent. It is therefore common practice to regularly treat water treatment systems with chemicals to counteract unwanted contamination. Many users of such water treatment systems wish to reduce the use of chemicals as much as possible, so purely mechanical filtration would be desirable.

[0008] However, in many cases it is not possible to install a filter because the filter housing, including the necessary connections to adjacent components of the water treatment system, cannot be accommodated in the available space, or can only be accommodated with considerable difficulty. On the one hand, this applies to the retrofitting of filters in existing water treatment systems, for example in recreational vehicles. On the other hand, however, it also affects the possibility of providing sufficient space for the installation of a filter when designing a new water treatment system. For example, the manufacturers of water treatment systems, e.g. manufacturers of the recreational vehicles mentioned, are faced with the task of using the space available in the vehicle, i.e. a limited amount of space with possiblyIn addition to the otherwise usual and necessary components of the water treatment system, there are no disruptive contours protruding into this space to accommodate a filter.

[0009] The invention is based on the object of improving a generic water filter in such a way that it allows installation even in confined spaces when retrofitting or when constructing a new water treatment plant.

[0010] This object is achieved by a water filter having the features of claim 1. Advantageous embodiments are described in the subclaims.

[0011] In other words, the invention proposes not using a rigid housing, but rather a flexible, bendable housing that can be deformed between the inlet and the outlet at a bending angle of at least 45°. Compared to a rigid, dimensionally stable, and therefore non-flexible housing, such as a filter cartridge, the proposed flexible housing allows installation even in confined spaces, as it can avoid walls, other components of a water treatment system, or other adjacent obstacles by being mounted with a corresponding bend in the respective installation situation.

[0012] In one embodiment, a hose is used as the housing. This represents an advantageous design in that, firstly, a hose is commercially available as a prefabricated element and is therefore economical. Secondly, hoses are pressure-stable, so they can easily withstand the pressures generated by pumps, such as those found in water treatment systems in mobile homes, yachts, boats, or the like. Compared to, for example, sewn bags or similar flexible, pliable housings, this ensures that the housing does not undesirably expand under the prevailing water pressure, which could lead to damage to the aforementioned adjacent obstacles or to the housing itself.

[0013] The housing's inlet and outlet are located at both ends of the hose. Compared to typical, almost cylindrical rigid housings or even spherical housings, such as those shaped like zeppelins, pears, or spheres, the hose has slimmer proportions, namely a comparatively smaller diameter in relation to its length. The length can be made large compared to the diameter of the hose, so that the water filter housing encloses a sufficiently large volume to accommodate a large filtering area. This has a positive effect on the water filter's hydraulic performance, namely the amount of water that can be extracted within a certain time. The comparatively long length of the hose is unproblematic in that the hose can be laid in a bend, deviating from its original, also cylindrical shape.This allows the hose to be laid avoiding obstacles so that other components of the water treatment system or other obstacles such as struts, frames or the like do not interfere with the arrangement of this special housing of the water filter.

[0014] In the following, a hose is mentioned in many places as a representative example of a flexible, bendable housing. However, where this is not structurally necessary due to the specific design as a hose, these exemplary references to a hose do not exclude other variants of a flexible, bendable housing.

[0015] For example, the hose can be laid in a nearly closed loop, namely bent 360°, so that it can be placed between two existing connection elements of a water treatment system - or one that is already provided for in a new design - and connected to these two connection elements. In an existing water treatment system, the connection between the two connection elements can first be separated and then the two connection elements can be offset from each other, for example by slightly bending a water pipe. The hose, bent 360°, can then be connected to the two connection elements like a single turn of a spiral. Depending on the design of the hose, this can be done with a bending radius of 200 mm or even smaller, e.g. 160 mm, so that the water filter can be installed even in confined spaces.Due to the flexibility of the water filter, it can not only be curved in one plane, e.g., as a nearly closed loop, but it can also deviate from this plane to avoid obstacles.

[0016] The filter surface used for ultrafiltration, which has a multitude of tiny filter openings, is proposed not to be formed by a single membrane, but rather by a multitude of hollow fibers, whose walls each form the filter surface and are provided with the filter openings. The hollow fibers can be arranged as fiber bundles, i.e., arranged closely spaced from one another or even adjacent to one another. With a circular cross-section of the hollow fibers, the interstices between adjacent hollow fibers provide flow paths for the water, allowing the raw water to flow to all hollow fibers. The higher the number of hollow fibers within the tube, the larger the filter surface provided, which positively influences the hydraulic performance and service life of the water filter.

[0017] The proposed water filter can therefore be retrofitted into almost all common water treatment systems found in practice or provided by the manufacturer from the outset, without the manufacturer having to make fundamental changes to the layout of a water treatment system for a vehicle type produced in small or large series. Due to the problem-free integration of the water filter into a water treatment system, it can, for example, be installed wherever it is most easily accessible. This allows the water filter to be removed regularly, for example once a year, and the filter surface to be freed of adhering residues in a backwash manner. This not only minimizes the risk of microbial contamination on the raw water side of the water filter, but also rinses the filter openings of the filter surface, restoring their optimal permeability.

[0018] In one embodiment, the hollow fibers each run in a U-shape within the tube, so that both ends of the hollow fibers face the same side of the housing, namely either the inlet or the outlet of the water filter. These ends of the hollow fibers are arranged together in a potting compound, but are exposed in that they lie at the edge of the potting compound and are not closed off by the sealing compound itself. The ends of the hollow fibers thus form flow openings through which the water can flow. The potting compound is dimensioned such that it fills the cross-section within the housing, through which water would otherwise flow, like a sealing plug, so that the water can only pass through the hollow fibers and exit the sealing plug from the ends of the hollow fibers.

[0019] For example, the hollow fibers can first be bent into a U-shape, then all the ends are aligned so that they lie in a single plane, if possible. This plane can be provided, for example, by the base of a cylindrical casting mold, and the ends of the hollow fibers are placed on this base. In this example, the ends of the hollow fibers can, for example, be pressed into a casting compound that was previously filled into the casting mold. Alternatively, however, it can also be provided that a casting compound is only filled into the casting mold when the ends of the hollow fibers are already in the casting mold. After the casting compound has hardened or set, it can be placed at a certain distance above the stated plane, e.g.above the mentioned bottom of the casting mold, are severed, for example by sawing through, so that the hollow fibers now run in a U-shape, their front ends are held together in the casting compound and end at the edge of the casting compound so that the material can flow freely through, namely in the separating or cutting surface.

[0020] A defined, high-precision outer surface of the material block formed by the potting compound with the hollow fibers arranged therein can be created by using a piece of pipe which, as a lost mold, is bonded to the potting compound after it has hardened and remains on the potting compound as an outer shell or lateral surface. The piece of pipe, with its precise surface and defined dimensions, enables very reliable sealing against the housing, e.g., the inner wall surface of a hose. This reliably prevents unwanted side flows in which water could pass unfiltered past the potting compound to the outlet. Depending on the orientation of the potting compound, the ends of the hollow fibers represent either inlets for the raw water or outlets for the water.In a design considered advantageous, the ends of the hollow fibers form the water outlets, so that the water enters the hose outlet exclusively through the hollow fiber outlets. This prevents the raw water from flowing into the hose through the comparatively small fiber end surfaces, but rather through the largest possible free cross-sectional area, thus avoiding an undesirably high pressure loss when flowing into the water filter.

[0021] Where the U-shaped hollow fibers are deflected, i.e., at the end of the fiber bundle opposite the front ends, the hollow fibers can, in one embodiment of the water filter, run over a holder that is itself securely held within the hose. This holder ensures that the water filter maintains its hydraulic performance and that the hollow fibers retain their original alignment, for example, running approximately parallel to one another. This prevents the hollow fibers from being pressed together in a disordered manner by the flowing water and / or the fiber bundle from being compressed into a disordered ball, which could impair the water throughput per unit of time.

[0022] To avoid undesirable tensile stress, which could damage the hollow fibers or impair their hydraulic performance, given the flexibility of the housing, the holder is mounted in one embodiment so that it can move longitudinally relative to the longitudinal direction of the housing, e.g., the hose. The holder, and thus the deflection end of the fiber bundle, is thus held movable relative to one end of the housing or to the adjacent inlet or outlet, so that even if the housing deforms, the deflection end of the fiber bundle is kept at a certain distance from the ends of the fibers, preventing undue stretching of the hollow fibers.

[0023] The holder can, for example, be held movable in the longitudinal direction of the hose with a certain amount of play by forming an elongated guide eyelet that is connected to a fitting element located at the end of the hose adjacent to the deflection end of the fiber bundle. This fitting element can, for example, be a fitting that serves to connect the water filter to an adjacent component of a water treatment system. The fact that the holder is held on a fitting element avoids having to damage the hose itself in order to be able to attach the holder directly to the hose. The fitting element, on the other hand, can have a sleeve-shaped section that is inserted into the hose and to which the holder is held directly or by means of an intermediate element.

[0024] The aforementioned elongated guide eyelet of the holder can, for example, enclose a pin that is molded onto the fitting element as an integral component. However, without requiring a specially designed fitting element, the aforementioned intermediate element can be used in an economically advantageous embodiment, so that a commercially available fitting element is used and equipped with the intermediate element. The intermediate element can, for example, be a cross pin that is mounted in two opposite bores of the fitting element and extends through the aforementioned elongated guide eyelet of the holder. Simple assembly of the holder can be made possible by having an open guide eyelet, so that the holder can be threaded onto the already mounted cross pin.If the opposite end of the fiber bundle, where the hollow fiber ends are located, is secured in the housing, the play with which the holder can move on the cross pin in the longitudinal direction of the hose is limited. Additional security to prevent unwanted detachment of the holder from the cross pin can be achieved by a constriction in the elongated guide eyelet, so that the holder is practically clipped onto the cross pin during assembly, overcoming this constriction.

[0025] In one embodiment of the water filter, a spacer is arranged in the hose between the hose wall and the hollow fibers. This spacer is designed and arranged in such a way that a flow path for the water is created between the fiber bundle and the hose wall. The spacer prevents the fiber bundle from being pressed directly against the hose wall. This can already be advantageous in a water filter in which the hose runs in a straight line, as the fibers cannot be pressed directly against the hose wall by the flowing water. The spacer is particularly advantageous in a curved hose because otherwise, without the spacer, hollow fibers would lie directly against the bend in the hose wall and their flow through there would be impaired.

[0026] Depending on how easily deformable the hollow fibers are, the spacer is designed to provide a large number of contact surfaces to which the hollow fibers can adhere, so that flow paths are created between these contact points along which water can flow into or out of the hollow fibers, depending on the design of the water filter.

[0027] In one embodiment, the spacer can be in the form of a spacer fabric made, for example, from plastic fibers. The spacer fabric represents a surface element which can initially be aligned flat in a plane, e.g. lying flat. Water can flow through the spacer fabric both within this plane, i.e. within its surface, and transversely thereto in the direction of the surface normal. A cost-effective design of the water filter can be supported by bending such a surface element into a cylinder shape and inserting it into the hose, so that a commercially available, flat spacer fabric can be used inexpensively as the spacer, which does not have to be manufactured in a cylindrical shape adapted to the inner diameter of the hose.

[0028] If the flat spacer fabric is bent into a cylinder and, after being relieved of pressure inside the hose, does not form a perfectly closed circular cross-section, but leaves a gap open longitudinally, this is not critical insofar as water can flow through the gap. And should individual hollow fibers penetrate the gap and adhere to the hose wall, the overall hydraulic performance is not significantly impaired.

[0029] However, if the flat spacer fabric is cut to such a size that it overlaps in some areas after it has been relieved of pressure inside the hose, this is also not critical insofar as it ensures that there is a distance between the hollow fibers and the hose wall all around the fiber bundle.

[0030] In one embodiment considered advantageous, the spacer is prefabricated as a hollow cylinder when inserted into the hose. If a spacer fabric is used as a spacer, this can be achieved by cutting a flat spacer fabric to precisely match the inner diameter of the hose, to a width such that the spacer fabric, rolled into a cylinder, can be easily inserted into the hose, while maintaining the smallest possible distance from the hose wall, possibly even touching the hose wall. This creates the largest possible interior space within the spacer, which can accommodate the largest possible number of hollow fibers, thus supporting the highest possible hydraulic performance of the water filter.

[0031] The spacer, which is bent into a hollow cylinder and formed from a sheet material, which can consist, for example, of the aforementioned spacer fabric, is provided with a seam in one embodiment considered advantageous, so that the cylindrically rolled sheet material reliably retains its cylindrical shape. For example, the two longitudinal edges of the aforementioned spacer fabric can be sewn together. This achieves several advantages: firstly, a gap is avoided between the two longitudinal edges, so that no hollow fibers can penetrate into such a gap. Secondly, an overlap of the sheet material can be avoided if the two longitudinal edges are sewn together with a butt joint. Avoiding the overlap creates the largest possible free cross-section within the hollow cylindrical spacer, so that the largest possible fiber bundle can be accommodated within it.Finally, thirdly, especially when the two longitudinal edges are sewn together in a butt-jointed manner, open cut edges of the sheet material with which the hollow fibers could come into contact are avoided, so that damage to the hollow fibers is practically excluded, which could otherwise lead to the creation of undesirably large openings in the filter surface and impair the quality of filtration.

[0032] All components of the water filter that come into contact with the water are preferably made of materials that are safe under food contact law, making the water filter suitable for drinking water production. What is considered "safe under food contact law" in this context depends on the respective local, regional, or national legislation. The hollow fibers, for example, which form the filter surface of the water filter, are made of a polyolefin plastic, in particular preferably PE, i.e., a polyethylene material that is considered food-safe in many countries, i.e., safe under food contact law, and is therefore approved for use in the food sector. Other components of the water filter can also be made of plastic, but also of metal - for example, stainless steel - or a mineral material.

[0033] The water filter can be connected to adjacent components of a water treatment system in various ways using both ends of its housing. For example, the housing, e.g., the aforementioned hose, can extend so far beyond the fiber bundle of hollow fibers at both ends and have a round cross-section that the housing forms a nozzle or sleeve at each of its two ends, allowing it to be connected to a nozzle or sleeve of an adjacent component and secured there using a connecting element typical in plumbing, such as a hose clamp or compression sleeve.

[0034] In one embodiment considered advantageous, the housing is equipped with a hose coupling at both its inlet and outlet. Hose couplings are known in many different designs from practical use, particularly in the field of plumbing. Therefore, such commercially available components in the form of hose couplings are often used in the installation of water treatment systems in vehicles such as mobile homes, boats, or the like, to detachably connect individual components of the water treatment system to adjacent components or to optionally disconnect them from them.The use of commercially available hose couplings on the water filter supports the most cost-effective production of the water filter, as the provision of special connection elements is not required, and it facilitates the connection of the water filter to the adjacent components of the water treatment system, which, as expected, in many cases also have such hose couplings.

[0035] The terms hose clamp and hose coupling used above refer to typical connecting elements in plumbing installations and are not tied to the fact that the housing must be designed as a hose.

[0036] Particularly if the water filter according to the invention is not intended for use in a new water treatment system, but rather is to be retrofitted into an existing water treatment system, the hose couplings at its two ends can advantageously be designed such that the two hose couplings interact with the hose couplings provided by the existing water treatment system. If two components connected by hose couplings are separated and deformed or possibly offset in such a way that the two hose couplings are not aligned with each other, but rather are offset from each other, the water filter according to the invention can be arranged between them in the form of a practically closed loop.The connection of the water filter to the two existing and separate hose couplings of the water treatment system can be carried out particularly easily if the hose couplings of the water filter are designed to complement the two previously separated hose couplings of the water treatment system.

[0037] In one embodiment, the housing of the water filter is formed by a hose which has a reinforced wall and, for example,

[0038] B. can be designed as a spiral hose. In this context, a spiral hose is not a spiral or helically bent hose, but rather a hose whose wall has a helical reinforcement. In the case of smooth-walled spiral hoses, this reinforcement can be arranged inside the hose wall, e.g. in the form of a metallic wire, or it can be designed as a rib made of a different plastic than the rest of the hose wall material. Apart from the helical reinforcement, the hose can have a different type of reinforcement, for example a net-like reinforcement made of metal or plastic as an integral part of the hose wall. In addition, the hose can have two types of reinforcement, e.g. both a helical reinforcement embedded in the wall and a net-like reinforcement on the outer surface of the hose wall.

[0039] For the sake of simplicity, the term "spiral hose" will be used below to refer to a reinforced hose, regardless of the reinforcement design. What is more important is that the spiral hoses exhibit a high degree of dimensional stability in their diameter due to their wall reinforcement. They are therefore suitable for use as suction hoses, as even when negative pressure prevails within the hose, the hose does not collapse flat but largely retains its circular cross-section. For the present application as a water filter housing, the spiral hose design facilitates the installation of the water filter in curves, possibly even in the form of a 360° loop, without forming kinks that would significantly impair flow through the hose.

[0040] It may be possible to dispense with the aforementioned spacer if inwardly projecting projections of the housing, e.g., a helical, circumferential, inwardly projecting rib of a spiral hose, fulfill the spacer function by creating a flow channel for the water between the projections, e.g., between two adjacent turns of the helical rib. In this case, the water filter also has a flow path for the water radially outside the fiber bundle, and the hollow fibers can be exposed to water flow all around, namely, even from outside the fiber bundle. Nevertheless, the aforementioned spacer can also be advantageously used in such a housing.Depending on the deformation behavior of the hollow fibers, the spacer can prevent the hollow fibers from adhering to the housing wall from the inside, following a wavy contour inside the housing, in which case the projections alone could not ensure the desired function of the spacer.

[0041] The proposed water filter can also be referred to as a hose filter due to its preferred design with an elongated housing, especially when this is actually in the form of a hose. The hose filter can withstand high stresses. An additional fabric arranged externally around the hose firstly allows the visual appearance of the hose filter to be influenced, e.g., by providing visual indications of the intended flow direction, and secondly also provides cut and wear protection, so that the outer protective shell protects the hose filter from external mechanical damage. Even a drop from a great height is no problem for the hose filter, as initial, non-public tests have shown, so that the hose filter exhibits a robustness that makes it suitable for many types of applications.Due to its robustness and dimensions, it can be easily transported, e.g., a large number of bag filters together in a box, or a single bag filter rolled up into a loop in a backpack, or a bag filter as part of an emergency kit, perhaps together with a tent and basic medical equipment, or the like.

[0042] For example, the hose filter can be deployed in crisis areas in difficult terrain and used for humanitarian purposes. In addition to permanent installation, the filter can also be mounted on the fly before or after pumps, or as the last unit, whereby the filtered water can be used directly or pumped into a reservoir. The hose filter is suitable for mobile use as an inline filter, connected to one end of a water hose or connected between two hoses. It is suitable for refueling ships and mobile homes, etc., and for the temporary storage of industrial and drinking water in designated containers.

[0043] The invention is explained in more detail below with reference to the purely schematic drawings.

[0044] Fig. 1 is a side view of an embodiment of an egg-shaped water filter,

[0045] Fig. 2 is a longitudinal section through the water filter of Fig. 1 in the region of its inlet, wherein the water filter is provided with an additional casing not shown in Fig. 1, and

[0046] Fig. 3 shows a longitudinal section through the water filter of Fig. 2 in the area of ​​its outlet.

[0047] Fig. 1 shows a water filter 1 which has a flexible housing 2 which is designed in the form of a hose. In the illustrated embodiment, the water filter 1 has, purely as an example, dimensions of approximately 1 m in length and approximately 4 cm in diameter. The illustrated hose is designed as a spiral hose whose hose wall is provided with a helical reinforcement 3. In the illustrated embodiment, the hose has smooth walls on the inside and outside, and the reinforcement 3 consists of a steel wire which runs inside the hose wall and is surrounded by the material of the hose wall. Deviating from the illustrated embodiment, the hose can have an additional reinforcement element as an integral part of the hose wall, which is designed as a net or grid and forms the outer surface of the hose wall.At both ends of the hose, the water filter 1 has an inlet 4 and an outlet 5. Unfiltered raw water can flow into the water filter 1 through the inlet 4. It is filtered at the water filter 1 and leaves the water filter 1 through the outlet 5 as water that has been purified of undesirable components of the raw water.

[0048] The inlet 4 and the outlet 5 of the water filter 1 are each formed by a so-called fitting, namely two commercially available hose couplings known from the field of plumbing technology, referred to as inlet fitting 6 and outlet fitting 7. The inlet fitting 6 is designed as a nut with an internal thread, and the outlet fitting 7 has a complementary external thread. The inlet and outlet fittings 6, 7 each protrude from the housing 2 in the manner of a pipe socket with the respective thread and enable connection to adjacent components of a water treatment system.

[0049] In the illustrated embodiment, the inlet and outlet fittings 6, 7 are designed such that they can be connected to specific components of a specific water treatment system without the use of intermediate pieces, adapters, or the like. The specific water treatment system can be a designed water treatment system that is still to be installed, or an existing water treatment system that has possibly been in use for some time. Depending on the design of the specific water treatment system, the inlet and outlet fittings 6, 7 can also be designed differently from the illustrated embodiment and as correspondingly different hose couplings. Alternatively, adapters or intermediate pieces can be used to connect the inlet and outlet fittings 6, 7 present on the water filter 1 to the components of a water treatment system. Fig.2 and 3 show that, on the other hand, the inlet and outlet fittings 6, 7 each have a sleeve-like section 8, which is provided with a plurality of externally circumferential holding ribs 9 and is inserted into the respective end of the hose. From the outside, the sleeve-like sections 8 are secured by means of stainless steel clamping sleeves 10, which are pushed onto the hose and clamped or pressed in, so that the inlet and outlet fittings 6, 7 are held securely and the sleeve-like sections 8 are held liquid-tight in the hose. Different material thicknesses of the clamping sleeves 10, which can be seen in Figs. 2 and 3, on the one hand - narrower - show the actual wall cross-section of the clamping sleeves 10 and on the other hand - wider - show the wall cross-section in the area of ​​a press bead, which is created by pressing the respective clamping sleeve 10.

[0050] Fig. 2 shows that a cross pin 11 is inserted into the sleeve-like section 8 of the inlet fitting 6, to which a holder 12 is connected, which extends downstream in the direction of the outlet 5, i.e. downwards in Fig. 2. At its upper or upstream end, the holder 12 forms an elongated guide eyelet through which the cross pin 11 extends. The elongated guide eyelet is open at the bottom, but forms a narrow point there, so that the holder 12 is secured on the cross pin 11. The elongated guide eyelet enables the holder 12 to be moved in the longitudinal direction of the housing 2, e.g. when the hose is bent in a U-shape by 180° as shown, or even further, e.g. B. in the manner of a closed 360° loop, and the holder 12 thereby changes its position compared to the position it assumes in the hose when the hose runs straight without bending.

[0051] At its lower or downstream end, the holder 12 is approximately hook-shaped. A plurality of individual hollow fibers 14 are deflected around the holder 12, so that the hollow fibers 14 each extend in a U-shape and form a fiber bundle, with all ends of the hollow fibers 14 located at the end of the fiber bundle remote from the holder 12. In the illustrated embodiment, the hollow fibers 14 are made of a polyethylene material and have tiny filter openings in their walls measuring 10 to 30 nm, in the illustrated embodiment in the form of pores each with a diameter of approximately 20 nm. The hollow fibers 14 are known from the field of ultrafiltration and are commercially available.

[0052] A spacer 15, which in the illustrated embodiment consists of a plastic spacer fabric, runs between the fiber bundles formed from the hollow fibers 14 and the tube. The spacer fabric is initially a flat element, rolled into a hollow cylinder whose two longitudinal edges are butted against each other and sewn together.

[0053] On the outside, the hose is covered by a sheath 16, which is designed as an abrasion-resistant plastic fabric and forms abrasion protection for the hose.

[0054] Fig. 3 shows that, in the direction of flow, shortly before the outlet 5, namely adjacent to the sleeve-like section 8 of the outlet fitting 7, a type of sealing plug fills the free inner cross-section of the housing 2 and connects to the inside of the hose wall. The spacer 15 extends as far as the sealing plug, but in the illustrated embodiment, does not run between the sealing plug and the hose. The supposed sealing plug does not actually seal the free inner cross-section of the hose. Rather, it is formed by a plastic sleeve 17 filled with a cured potting compound, which envelops the ends of the hollow fibers 14 inserted into the sleeve 17. The ends of the hollow fibers 14 open as outlet openings at the downstream—in Fig. 3, the upper—end of the potting compound and the sleeve 17.Raw water, which flows into the hose at the inlet 4 through the inlet fitting 6 and along the cross pin 11 and the holder 12, is distributed inside the hose around the hollow fibers 14 and also flows through the spacer 15, so that the.

[0055] The surfaces of the hollow fibers 14 are wetted as completely as possible by the raw water. The water passes through the filter openings in the walls of the hollow fibers 14 even at low water pressure and reaches the interior of the hollow fibers 14 as filtered water. It flows to the front ends of the

[0056] Hollow fibers 14 and exits there from the hollow fibers 14 and the casting compound - and thus also from the sleeve 17 - to flow further through the outlet fitting 7 and leave the water filter 1 through the outlet 5.

[0057] Reference symbol:

[0058] 1 water filter

[0059] 2 housings

[0060] 3 Reinforcement

[0061] 4 Entrance

[0062] 5 Outlet

[0063] 6 Inlet fitting

[0064] 7 Outlet fitting

[0065] 8 sleeve-like section

[0066] 9 Holding rib

[0067] 10 clamping sleeve

[0068] 11 Cross pin

[0069] 12 holders

[0070] 14 hollow fiber

[0071] 15 spacers

[0072] 16 Sheathing

[0073] 17 sleeve

Claims

Claims:

1. A water filter (1) comprising a housing (2) and an inlet (4) designed to feed unfiltered raw water into the housing, a filter surface having a plurality of tiny filter openings, and a water outlet (5) designed to feed filtered water out of the housing (2), wherein the filter surface is arranged between the inlet (4) and the outlet (5) in such a way that the water flowing from the inlet (4) to the outlet (5) flows through the filter surface, characterized in that the housing (2) is designed to be flexible in such a way that the water filter (1) is deformable between the inlet (4) and the outlet (5) at a bending angle of at least 45°, and wherein the filter surface is formed by a plurality of hollow fibers (14), the walls of which have the filter openings.

2. Water filter according to claim 1, characterized in that the housing (2) is designed as a hose, a first end of the hose has the inlet (4), a second end of the hose has the outlet (5).

3. Water filter according to claim 1 or 2, characterized in that the hollow fibers (14) each run in a U-shape within the housing (2), and the front ends of the hollow fibers (14) are arranged in a potting compound, wherein the front ends of the hollow fibers (14) lie at the edge of the potting compound and form flow openings for the water.

4. Water filter according to claim 3, characterized in that the front ends of the hollow fibers (14) lie at the edge of the potting compound and form outlet openings for the water, wherein the potting compound closes the cross section of the housing (2) upstream of the outlet (5) in such a way that water reaches the outlet (5) of the housing (2) exclusively through the outlet openings of the hollow fibers (14).

5. Water filter according to claim 3 or 4, characterized in that the hollow fibers (14) run over a holder (12) in the region of their U-shaped deflection opposite the front ends, wherein the holder (12) is held in a displacement-proof manner in the longitudinal direction of the housing (2).

6. Water filter according to one of the preceding claims, characterized in that a spacer (15) is arranged within the housing (2) between the housing wall and the hollow fibers (14) in such a way that a flow path for the water is created radially outside a fiber bundle formed from the hollow fibers (14).

7. Water filter according to claim 6, characterized in that the spacer (15) is designed as a spacer fabric through which water can flow within the area formed by the spacer fabric and transversely thereto.

8. Water filter according to one of the preceding claims, characterized in that that the hollow fibers (14) consist of a polyethylene material.

9. Water filter according to one of the preceding claims, characterized in that the housing (2) is provided with a hose coupling at its inlet (4) and at its outlet (5).

10. Water filter according to one of the preceding claims, characterized in that the housing (2) is provided with a reinforcement (3) limiting the extensibility of the housing (2).

11. Water filter according to one of claims 2 to 10, characterized in that the housing (2) designed as a hose is designed as a spiral hose with a helically extending reinforcement (3).

12. Water filter according to one of the preceding claims, characterized in that the housing (2) is provided on the outside with a casing (16) in such a way that the casing (16) forms abrasion protection for the housing (2).

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