WO1998010143A1 - Filter element - Google Patents

Abstract

A filter element (1) for liquid permeable floor area fastening (17), a floor covering plate (15), a manhole cover (15), a sewage cavity or the like, with at least one pre-filtering layer (3) in the direction of the through-flow (2) and at least one following filter layer (4,4'), wherein the free through-flow sections (a, b, b') of each layer (3, 4, 4') increase from layer to layer in the direction of the through-flow. The filter also comprises a housing (5) which surrounds the filter layers (4,4') in a framelike manner and maintains them, wherein each filter layer (4,4') is formed from granular material and the grains are available in loose form or linked to each other by a weak binding agent.

Description

 Filter element

The present invention relates to a filter element for constructing a liquid-permeable floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with at least one pre-filter layer in the flow direction and at least one subsequent filter layer, the free flow cross-sections of each layer increasing in the flow direction from layer to layer, and with a casing which at least surrounds and holds the filter layer (s) like a frame.

The invention further relates to a filtering floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with a rigid plate-shaped base body, which is provided with a plurality of receiving openings which open at the bottom side of the base body or into drainage channels running in the base body, and one Process for their production.

A filter element of the type mentioned in the introduction is known from EP 0 651 835. The multi-layer structure with increasing flow cross-sections ensures that solids contained in the liquid to be filtered can only penetrate into the fine-pored pre-filter layer up to a certain particle size. Grain sizes that are equal to or smaller than the pores in the pre-filter layer can penetrate into the filter element, but are not retained there or do not move the filter element, but are passed freely through the filter body and discharged again with the liquid medium. Any contamination of the liquid, such as oils or petrol, is absorbed to a certain degree in the filter element and regenerated in a biological degradation process; the porosity of the material and the free spaces mean that the filter element is automatically ventilated. In the known filter elements, the filter layers are formed from porous, firmly bonded materials. While on the one hand this brings with it excellent strength and load-bearing properties of the filter element, which, for example allow direct pedestrian or vehicle traffic, it has on the other hand, ^¬ the disadvantage that frost action, for example, can lead to explosive cracks and thus destruction of the filter element.

The aim of the invention is to develop a filter element of the type mentioned in the introduction in such a way that frost protection is ensured while maintaining the advantages described. This aim is achieved according to the invention in that each filter layer is formed from granular material, the granules either being in loose form or being connected to one another by a weak binder.

In the present description, a “granular material” is understood to mean any type of particulate material. The granules (or particles of the particulate material) can be of any shape and size, e.g. round or angular, and in turn consist of any material, e.g. made of porous or impermeable, rigid or elastic material. The granular material can have a homogeneous structure from one type of granule, but it can also consist of a mixture of different types of granule, which differ in size, shape and / or material.

In this way a mutual movement of the granules is possible in the event of frost, so that these can withstand the pressure e.g. avoid freezing water and can distribute or shift accordingly within the boundaries of the casing and the prefilter layer without destroying the casing or the prefilter layer. The optional use of a weak binder for the granules preferably serves for transport purposes, for example if the elasticity of the casing is insufficient to keep the granules wedged or supported against one another during transport. The binding force of the binding agent is preferably chosen to be sufficiently strong that it is sufficient to prevent the granules from falling out of the casing when the filter element is lifted, transported and laid at its place of use.

The free movement of the granules enables the return to their original would be. In addition, the vibrations that occur when there is frost, when walking on or driving onto the filter element improve the self-cleaning effect of the filter layer.

A preferred embodiment of the invention is characterized in that the clear width of the casing decreases in the flow direction, preferably tapers conically. As a result, the compressive force exerted on the granulate body when the force is exerted (e.g. driving on) can be dissipated onto the casing. Of course, the invention also takes into account the alternative that the clear width of the casing in the flow direction remains the same or increases.

A particularly advantageous measure to allow the displacement of the granules consists in producing the pre-filter layer and the sheathing from flexible, preferably elastic material. In this case it is particularly favorable if the pre-filter layer is formed in one piece with the casing. This variant leads to a particularly simple construction of the filter element.

Alternatively, the casing could also be made of rigid and only the pre-filter layer made of flexible, preferably elastic material, which has the advantage that the filter element has exactly predefined circumferential dimensions.

Furthermore, it is possible to manufacture both the casing and the pre-filter layer from rigid material and to connect them relatively movably in the flow direction by means of an overlapping butt joint. Instead of an overlapping butt joint, a connection via a flexible, preferably elastic seal can also be provided. In any case, a chamber for the granules inside the filter layer that can be expanded in the direction of flow results in the event of frost, whereby it is ensured that the surface of the filter element on the liquid inlet side has its predefined configuration, e.g. even, maintains.

In all of the embodiments described, a particularly advantageous development is characterized in that a rigid support body is provided, which is arranged downstream of the filter layer (s) in a supporting manner and is provided with liquid passage openings, the free passages Flow cross sections of the support body are equal to or larger than the free flow cross sections of the adjacent filter layer.

The support body thus closes the sheathing on the side facing away from the pre-filter layer, so that there is an all-round sheathing for the granules, which considerably facilitates the handling of the filter element. The load-bearing capacity, the ability to walk on and pass through the filter element does not depend on the quality of the surface of the filter element, but rather is defined by the load-bearing capacity of the casing and the support body.

The outer circumference of the support body preferably decreases in the flow direction, which means that the support body is positively anchored in the flow direction in a corresponding receptacle in a floor covering, a manhole cover or the like. enables.

According to a preferred embodiment of the invention, the support body can be connected to the casing by means of an overlapping butt joint so as to be relatively movable in the flow direction in order to enable a relative movement of the granules.

Alternatively, the support body can be made in one piece with the sheathing, so that it forms a pot-like receptacle for the granulate body, which is closed off by the pre-filter layer. In this variant, the free movement of the granules must be ensured by a corresponding flexible or elastic design of the pre-filter layer or a flexible connection of the pre-filter layer to the casing or elastic design of the granules.

In a further development of the invention, a rigid frame body can also be provided, which surrounds the casing in a form-fitting manner. The frame body increases the strength or load capacity of the filter element. The frame body can preferably be made in one piece with the support body, so that there is a pot-like receptacle for the granules and their casing. In any case, it is particularly advantageous if, according to a further feature of the invention, the outer circumference of the casing or of the frame body which may be present decreases in the flow direction. This measure has the advantage described in connection with the support body that the filter element can be anchored in a positive manner in the direction of flow in a surrounding base plate, filter plate, in compacted soil, etc.

An alternative embodiment of the invention, created for another application, is characterized in that the sheathing or the frame body, if present, has an external shape suitable for form-fitting laying in connection with similar neighboring filter elements. A further application opens up if, according to a further variant of the invention, the casing or the frame body, if present, with a peripheral flange for anchoring in the inlet of a sewage shaft or the like. Is provided. In any case, it is particularly favorable if the pre-filter layer is made of wear-resistant material, etc. preferably made of porous concrete or synthetic resin, asphalt or the like, porous plastic, perforated metal or plastic, fabric, in particular plastic fabric or GRP fabric or similar material.

According to a preferred feature of the invention, it is provided that the surface of the pre-filter layer on the liquid inlet side has a concave shape. When the filter element is installed vertically, this makes it easier for the liquid to flow into the pre-filter layer.

The surface of the prefilter layer on the liquid inlet side is preferably structured, preferably ribbed or nubbed. This allows the filter element to better adapt to the special application, e.g. as a flooring element.

In all embodiments of the invention, the filter layer is preferably formed from single-grain or multigrain granulate mixtures, etc. preferably made of concrete granulate, plastic or Synthetic resin granules or balls, or of gravel. Even an elastic design of the filter grains is possible. With these materials, the free flow cross-sections can be set as desired in a wide range depending on requirements and application. On the other hand, these materials have a corresponding strength in order to enable the forces applied to the pre-filter layer, for example when driving over them, to be transmitted to the substrate or the support body.

Concrete mortar or synthetic resin, plastic or the like is preferably used as an optional binder for the granules. Similar materials can of course also be used. The binders used can simply be mixed into the granules and form connections at the points of contact which can separate when exposed to frost.

Concrete, plastic, metal, fabric, in particular plastic fabric or GRP fabric, are preferably provided as materials for the casing.

According to a further feature of the invention, it can be provided that the outside surface of the casing is structured, preferably ribbed or nubbed, formed and / or provided with an adhesive coating, adhesive elements, pins or the like, for example made of polymers, which is the formation of a Press or press fit of the filter element in a surrounding, in particular conical receptacle in a floor surface fastening, plate or compacted concrete promotes. The adhesiveness of filter elements used in a floor surface due to vibrations, frost or the like. can be further improved. According to the invention, all high-strength materials are taken into account for the support body or the frame body, if any, preferably concrete, metal, plastic, high-strength bonded porous materials such as seepage concrete, asphalt mixtures, synthetic resin-bound single-grain or multi-grain material or the like. It is particularly advantageous if the passage openings are molded into the support body or machined in, for example punched or drilled. A further aspect of the invention consists in the creation of a filtering floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with a rigid plate-shaped base body, which is provided with a plurality of receiving openings which open out into the base body or run into drainage channels running in the base body and which are characterized according to the invention by filter elements of the type presented here inserted into the receiving openings. It is particularly advantageous if the receiving openings are tapered in the flow direction, so that the filter elements are held in the flow direction, etc. with a correspondingly complementary training by positive locking, with which any high loads are possible.

According to a further feature of the invention, the support bodies of the filter elements are preferably formed in one piece with the base body, which eliminates the need for separate support bodies.

Yet another aspect of the present invention consists in a method for producing a liquid-permeable floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with the steps

Manufacture of a rigid plate-shaped base body from in-situ concrete, asphalt, bitumen or the like. with the formation of a plurality of preferably conical receiving openings which open out on the underside of the base body or open into drainage channels running in the base body, and

Inserting filter elements of the type presented here into the receiving openings formed.

An alternative embodiment consists in a method for producing a liquid-permeable floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with the steps

Providing a rigid plate-shaped base body made of in-situ concrete, asphalt, bitumen or the like, incorporating a plurality of preferably conical receiving openings which open out at the underside of the base body or into drainage channels running in the base body, and Inserting filter elements of the type presented here into the receiving openings formed.

A further variant is a method for producing a liquid-permeable floor surface fastening, with the steps

Providing a base body from a compressed or sealed floor surface, below which there is an uncompressed, porous sub-floor.

Incorporation of a plurality of receiving openings opening into the sub-floor into the compacted or sealed bottom surface, and

Inserting filter elements of the type presented here into the receiving openings formed.

The invention is explained in more detail below with reference to exemplary embodiments shown in the accompanying drawings. 1 to 13 show different embodiments of the filter element according to the invention in longitudinal section, FIGS. 14 to 17 show different application forms of the filter element according to the invention in longitudinal section, FIGS. 18 to 20 schematically show different cross-sectional shapes of the filter element and FIG. 21 to 26 examples of grouping patterns of filter elements in the use cases of FIGS. 15 to 17 in plan view.

1 and 2 is an inventive. Filter element 1 shown in its simplest forms. 1, the filter element 1 is composed of a pre-filter layer 3 and a subsequent filter layer 4, seen in the flow direction 2, which are surrounded by a frame-like casing 5. The term "frame-like" is not tied to any special inner or outer shape of the casing 5, but rather defines that the casing 5 laterally surrounds the filter layer 4 in the sense of the illustration. The thickness of the pre-filter layer 3 is significantly less than the thickness of the filter layer 4 and is, for example, only 1 to 30%, preferably 1 to 10%, of the thickness of the filter layer 4. The prefilter layer 3 is made of a porous or perforated material, the minimum or average free flow cross sections of which are shown schematically as dimension "a". The filter layer 4 is formed from granular material, the averaged free flow cross sections between the schematically represented granules being shown schematically as dimension "b". It is crucial that the free flow cross-sections b of the filter layer 4 are larger than the free flow cross-sections a of the pre-filter layer 3, so that any foreign matter that has passed through the pre-filter layer 3 does not move the filter layer 4 but is discharged. Contaminations such as oils or petrol are absorbed in the filter layer 4 and regenerated in a biological degradation process, the porosity of the filter layer 4 simultaneously ensuring that the filter element is ventilated and vented automatically.

The clear width of the sheathing 5 decreases in the direction of flow 2, as a result of which the loose granules of the filter layer 4 wedge against one another due to their own weight and thus secure against falling out of the sheathing 5 when the filter element is being transported - provided the vibrations are not too great are. This measure can be supported in that the casing 5 made of flexible, in particular elastic material, e.g. in the manner of a clamping ring. Alternatively or additionally, the filter layer 4 can be tied with a weak binder, the binding force of which is just sufficient to hold the granules during transport and laying, but in the event of shocks, frost effects, exposure to road salt or the like. triggers so that a free relative movement of the granules in the filter layer 4 is possible.

The casing 5 does not necessarily have to be tapered on the inside; it could also have an almost constant cross section in the flow direction or expand. This also applies to their outer circumference.

To the expansion of the filter layer 4 in the event of frost or the like. to be able to record - lo ¬

Most cases, the entire filter element 1 in the surrounding base plate, bottom surface mounting, etc. in the flow direction so that it can move so that on the open side of the casing 5 emerging granules can lift the filter element slightly out of its seat. However, an expandable chamber for the filter layer 4 is preferably created. For this purpose, the pre-filter layer 3 is connected to the sheathing 5 via an overlapping butt joint 6, so that the pre-filter layer 3 can move parallel to the flow direction 2 with respect to the sheathing 5. Additionally or alternatively, a flexible, preferably elastic seal 7 can be provided between the prefilter layer 3 and the casing 5 and / or the prefilter layer 3 or the casing 5 can be made flexible or elastic, as will be described later. Fig. 2 shows a similar embodiment as Fig. 1, with the difference that the pre-filter layer 3 and the sheath 5 are made in one piece and a further filter layer 4 'is provided after the filter layer 4. The free flow cross sections of the filter layer 4 'are shown schematically as dimension b' and are larger than the free flow cross sections b of the filter layer 4. More than two filter layers 4, 4 'can also be arranged in succession, the free flow cross sections of all layers 3 , 4, 4 'etc. increase from layer to layer in flow direction 2 (not shown).

FIG. 3 shows an embodiment similar to that of FIG. 2, a rigid support body 8 being provided downstream of the last filter layer 4 ′ and being provided with liquid passage openings 9. The free flow cross-sections of the support body 8 have the dimension c and are equal to or larger than the free flow cross-sections b 'of the adjacent filter layer 4' (not shown true to relation in the drawing). The following generally applies: a << b <b '<c According to FIG. 4a, the support body 8 can be connected to the casing 5 by means of an overlapping butt joint 9' in the flow direction in a relatively movable manner in order to form an expandable chamber for the filter layer (s) 4, 4 ' etc. to form. 4b shows an embodiment in which the clear width of the casing 5 increases in the flow direction and the casing 5 also surrounds the support body 8. Again, the expandable chamber can be formed by flexible or elastic design of the casing and / or the prefilter layer, in which case the support body 8 can be connected to the casing 5, for example pressed or glued, or the expandable chamber is made possible by the relatively movable surface - Lapping interface 9 "formed between casing 5 and support body 8.

5, the support body 8 can also be hollow.

Fig. 6 shows that the casing 5 can also surround and hold the support body 8 laterally. In this example, the casing 8 is equipped with a peripheral flange 10, the purpose of which will be explained later in connection with the embodiment of FIG. 11.

7, the support body 8 can also be formed in one piece with the casing 5, so that there is a pot-like receptacle for the filter layer (s) 4, 4 'etc.

8 shows an embodiment in which, in addition to the casing 5, a rigid frame body 11 is provided, which surrounds the casing 5 and, in the example shown, the support body 8 in contact. The frame body 11 can be used to give the entire filter element 1 a defined circumferential shape if a flexible or elastic sheathing 5 is used. On the other hand, it enables or strengthens the cohesion between the prefilter layer 3, the casing 5 and the support body 8. Finally, the frame body 11, as can be seen from FIGS. 9a-9c and 10, can be provided with such an outer shape or peripheral shape that the entire filter element 1 can be laid in a positive connection with similar filter elements 1 of the same type. Alternatively, the frame body 11, in the same way as the casing 5 in the embodiment of FIG. 6, can be provided with a peripheral flange 12, which anchors the filter element 1 in the inlet 13 of a sewer shaft 14 or the like. enables (Fig. 11). Regarding the embodiments in FIGS. 9b and 9c, it should also be noted that the clear width of the casing 5 increases in the flow direction. In Fig. 9c, the support body 8 is made in two parts, etc. from an inner part 8 'made of, for example, porous material, which is provided with through openings 9 and inserted into a frame-like second part 8 "in such a way that it is held in a form-fitting manner in the flow direction.

12a and 12b show embodiments in which the frame body 11 is made in one piece with the support body 8. In Fig. 12b, the inside width of the casing 5 remains approximately constant in the flow direction.

FIG. 13 shows a combination of the embodiments of FIGS. 11 and 12a, the frame body 11 being formed in one piece with the support body 8 and having a peripheral flange 12 for anchoring in the inlet 13 of a sewage shaft 14.

According to FIG. 14 a, the frame body 11 can also be formed in two parts from an upper part 11 ′ and a lower part 11 ″, the dividing line running at the level of the support body 8 and forming an inner shoulder 11 ′ ^■ ′ for its support. FIG. 14 b shows a floor surface fastening element 15, for example a floor tile, floor slab, a paving stone or the like, which is equipped with a filter element 1 with support and frame bodies 8, 11. Such a floor surface fastening element can of course also be equipped with a plurality of filter elements 1, and one example of a manhole cover equipped with nine ^'filter elements 1 is shown in Fig. 15 in longitudinal section.

16 shows a floor surface fastening 17, which can be carried out in principle in an endless manner, with a rigid base body 18, which is provided with a plurality of receiving openings 20 opening out on the underside 19 of the base body, into which filter elements 1 are inserted. The receiving openings 20 are tapered in the flow direction 2 and hold the filter elements 1 positively. Alternatively (not shown), the support bodies 8 of the filter elements 1 could be formed in one piece with the base body 18.

FIG. 17 shows a variant of the floor surface fastening from FIG. 16, wherein in the interior of the base body 18 transverse locking fende drainage channels 21 are recessed, into which the receiving openings 20 open.

The production of the floor covering plate or manhole cover plate 15 or of the floor surface fastening takes place either by first manufacturing the base body 18 with the receptacles 20 and then inserting the filter elements 1 into the receiving openings 20, or by starting from an existing base body 18 is then incorporated the receiving openings 20, for example drilled, milled or the like, and then the filter elements 1 are used. Of course, the filter elements 1 could also be cast directly into the material of the base body 18. The base body 18 can also be formed by compacting or sealing the surface layer of a porous floor, with a non-compressed, porous sub-floor 22 remaining below the base body 18.

In order to make the support body 8 of the filter elements 1 in one piece with the base body 18, it is sufficient to provide or incorporate bag-shaped receiving openings 20 and to provide the bottom of the receiving openings with passage openings 9.

The filter elements 1 can have any cross section, e.g. round, oval, angular, square, polygonal, as can be seen from the examples of FIGS. 18 to 20. Several filter elements 1 in a floor mounting, a floor mounting, a manhole cover or the like. can be arranged in any pattern, e.g. as shown in Figs. 21 to 26.

It is understood that the features of the different embodiments shown in the figures can be combined in any way; the representation of all possible combinations would exceed the scope of the present application. It is essential that the granules of the filter layer 4 are freely movable in the installed state of the filter element 1 in order to reduce the pressure e.g. to be able to avoid freezing water without affecting the multilayer structure and the external structural integrity of the filter element.

Any highly abrasion-resistant materials are suitable as materials for the prefilter layer 3, be they rigid or flexible or elastic, for example porous concrete, asphalt, porous plastic, perforated metal sheets or plastic foils, plastic mesh, GRP mesh etc. The surface 3 '(FIG. 3) of the pre-filter layer 3 on the liquid inlet side can be concave, ribbed, nubbed or otherwise structured . Suitable materials for the filter layer 4 are single-grain or multigrain granulate mixtures of concrete granulate, plastic or synthetic resin granulate or spheres or gravel. The granules can be rigid or elastic, porous or impermeable. The modulus of elasticity and / or the degree of porosity can also be selected differently for each component of a multigrain granulate mixture. Concrete mortars of low strength, synthetic resin etc. are suitable as binders for the filter layer 4.

The casing 5 can be made of the same material as the pre-filter layer 3, preferably made of metal (e.g. steel) or plastic, but also porous concrete, concrete with molded channels or also from wear-resistant fabrics, plastic fabrics or GRP fabrics. The outside surface 5 '(FIG. 3) of the casing 5 can be ribbed, nubbed or otherwise structured or provided with an adhesive coating or adhesive elements.

The support body 8 or the frame body 11 consist of high-strength material, preferably concrete, metal, plastic, high-strength bonded materials such as seepage concrete or the like. The through openings 9 are either molded or mechanically incorporated, e.g. punched or drilled.

The free relative mobility of the granules is also an advantage if no frost action is possible, e.g. in countries with a consistently warm climate, because it enables the forces applied to the pre-filter layer to be passed on to the substrate in a non-destructive manner.

Claims

Claims: 1. filter element for building up a liquid-permeable floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with at least one pre-filter layer in the flow direction and at least one subsequent filter layer, the free flow cross-sections of each layer increasing in the flow direction from layer to layer, and with a casing which surrounds and holds at least the filter layer (s) in a frame-like manner, characterized in that each filter layer (4, 4 ') is formed from granular material, the granules either being in loose form or by a weak binder are interconnected. 2. Filter element according to claim 1, characterized in that the clear width of the casing (5) decreases in the flow direction, preferably tapers conically. 3. Filter element according to claim 1 or 2, characterized in that the pre-filter layer (3) and the casing (5) are made of flexible, preferably elastic material. 4. Filter element according to one of claims 1 to 3, characterized in that the pre-filter layer (3) with the casing (5) is integrally formed. 5. Filter element according to claim 1 or 2, characterized in that the casing (5) is made of rigid and the pre-filter layer (3) made of flexible, preferably elastic material. 6. Filter element according to claim 1 or 2, characterized in that the casing (5) and the pre-filter layer (3) made of rigid material and are connected via a overlapping butt joint (6) relatively movable in the flow direction. 7. Filter element according to .Anspruch 1 or 2, characterized in that the casing (5) and the pre-filter layer (3) made of rigid material and are connected to each other via a flexible, preferably elastic seal (7). 8. Filter element according to one of claims 1 to 7, characterized in that a rigid support body (8) is provided. hen, which is arranged downstream of the filter layer (s) (4, 4 ') to support it and is provided with liquid passage openings (9), the free flow cross-sections (c) of the support body (8) being equal to or larger than the free flow cross-sections ( b, b ') of the adjacent filter layer (4, 4'). 9. Filter element according to claim 8, characterized in that the outer circumference of the support body (8) decreases in the flow direction (2). 10. Filter element according to claim 8 or 9, characterized in that the support body (8) with the casing (5) via an overlapping butt joint (9) in the flow direction (2) is relatively movable. 11. Filter element according to claim 8 or 9, characterized in that the support body (8) with the casing (5) is made in one piece. 12. Filter element according to one of claims 1 to 11, characterized in that a rigid frame body (11) is provided which positively surrounds the casing (5). 13. Filter element according to claim 12 in connection with one of claims 8 to 11, characterized in that the frame body (11) with the support body (8) is integrally formed. 14. Filter element according to one of claims 1 to 13, characterized in that the outer circumference of the casing (5) or the frame body (11) which may be present decreases in the flow direction (2). 15. Filter element according to one of claims 1 to 13, characterized in that the casing (5) or the frame body (11), if present, has an external shape suitable for positive installation in connection with similar neighboring filter elements (1). 16. Filter element according to one of claims 1 to 13, characterized in that the casing (5) or the frame body (11), if present, with a peripheral flange (10, 12) for anchoring in the inlet (13) of a sewage shaft (14) or the like. Is provided. 17. Filter element according to one of claims 1 to 16, characterized in that the pre-filter layer (3) is made of wear-resistant material. 18. Filter element according to one of claims 1 to 17, characterized in that the pre-filter layer (3) made of porous Concrete or synthetic resin, asphalt or the like. is made. 19. Filter element according to one of claims 1 to 17, characterized in that the pre-filter layer (3) is made of porous plastic. 20. Filter element according to one of claims 1 to 17, characterized in that the pre-filter layer (3) is made of perforated metal or plastic. 21. Filter element according to one of claims 1 to 17, characterized in that the pre-filter layer (3) is made of fabric, in particular plastic fabric or GRP fabric. 22. Filter element according to one of claims 1 to 21, characterized in that the liquid inlet side surface (3 ') of the pre-filter layer (3) is concave. 23. Filter element according to one of claims 1 to 22, characterized in that the liquid inlet side Surface (3 ') of the prefilter layer (3) is structured, preferably ribbed or nubbed, is formed. 24. Filter element according to one of claims 1 to 23, characterized in that the filter layer (4, 4 ') is formed from single-grain or multigrain granule mixtures. 25. Filter element according to one of claims 1 to 24, characterized in that the filter layer (4, 4 ') is formed from granulated concrete. 26. Filter element according to one of claims 1 to 24, characterized in that the filter layer (4, 4 ') is formed from preferably elastic (n) plastic or synthetic resin granules or balls. 27. Filter element according to one of claims 1 to 24, characterized in that the filter layer (4, 4 ') is formed from gravel. 28. Filter element according to one of claims 1 to 27, characterized in that the binder which may be used is concrete mortar. 29. Filter element according to one of claims 1 to 27, characterized in that the optionally used binder synthetic resin, plastic or the like. is. 30. Filter element according to one of claims 1 to 29, characterized in that the casing (5) is made of concrete, plastic or metal. 31. Filter element according to one of claims 1 to 29, characterized in that the casing (5) is made of fabric, in particular plastic fabric or GRP fabric. 32. Filter element according to one of claims 1 to 31, characterized in that the outer surface (5 ') of the casing (5) is structured, preferably ribbed or nubbed, is formed. 33. Filter element according to one of claims 1 to 32, characterized in that the outside surface (5 ¹ ) of Casing (5) with an adhesive coating, adhesive elements, pins or the like, e.g. made of polymers. 34. Filter element according to one of claims 8 to 33, characterized in that the support body (8) and / or the possibly present frame body (11) made of high-strength material, preferably concrete, metal, plastic, high-strength bonded porous materials such as seepage concrete, Asphalt mixtures, synthetic resin-bound single or multigrain material or the like. are / is manufactured. 35. Filter element according to one of claims 8 to 34, characterized in that the passage openings (9) in the support body (8) molded or mechanically incorporated, e.g. are punched or drilled. 36. Filtering floor surface fastening, floor covering plate, manhole cover, sewage trough or the like., With a rigid plate-shaped base body (18) with a plurality of on the underside (19) of the base body (18) in or out in the base body (18) Provided drainage channels (21) opening receiving openings (20), characterized by filter elements (1) according to one of claims 1 to 35 inserted into the receiving openings (20). 37. Floor surface fastening according to claim 36, characterized in that the receiving openings (20) are tapered in the flow direction (2). 38. Floor surface fastening according to claim 35 or 36, with filter elements according to one of claims 8 to 35, characterized in that the support body (8) of the filter elements (1) with the base body (18) are integrally formed. 39. Method for producing a liquid-permeable floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with the steps Manufacture of a rigid plate-shaped base body (18) from in-situ concrete, asphalt, bitumen or the like. with the formation of a plurality of preferably conical receiving openings (20) opening on the underside (19) of the base body (18) or opening into drainage channels (21) running in the base body (18), and Inserting filter elements (1) according to one of claims 1 to 35 into the receiving openings (20) formed. 40. A method for producing a liquid-permeable floor surface fastening, floor covering plate, manhole cover, sewage trough or the like, with the steps Providing a rigid plate-shaped base body (18) made of in-situ concrete, asphalt, bitumen or the like, Incorporation of a plurality of preferably conical receiving openings (20) opening on the underside (19) of the base body (18) or opening into drainage channels (21) running in the base body (18), and Inserting filter elements (1) according to one of claims 1 to 35 into the receiving openings (20) formed. 41. A method of making a liquid-permeable bottom surface fastener, comprising the steps Providing a base body (18) from a compressed or sealed bottom surface, below which there is a non-compacted, porous sub-floor (22), Incorporation of a plurality of receiving openings (20) opening into the underbody (22) into the compacted or sealed bottom surface, and Inserting filter elements (1) according to one of claims 1 to 35 into the receiving openings (20) formed.