FUEL FILTER

Abstract

A fuel filter may include a housing and a coalescer arranged in the housing. The coalescer may be configured to separate out water contained in a fuel. The coalescer may include a coalescer material suitable for coalescing water. The fuel may be flowable through the coalescer in a throughflow direction. The coalescer material may include a plurality of fibres, which may have a primary orientation that is essentially parallel to the throughflow direction.

Claims

1. A fuel filter, comprising: a housing; a coalescer arranged in the housing, the coalescer configured to separate out water contained in a fuel; the coalescer including a coalescer material suitable for coalescing water; wherein the fuel is flowable through the coalescer in a throughflow direction; and wherein the coalescer material includes a plurality of fibres having a primary orientation that is essentially parallel to the throughflow direction.

2. The fuel filter according to claim 1, further comprising a particle filter, wherein: the particle filter is configured as a ring filter element; and the coalescer has a ring-shaped cross-section.

3. The fuel filter according to claim 1, wherein the plurality of fibres have a diameter greater than 1 μm and less than 30 μm.

4. The fuel filter according to claim 1, wherein the plurality of fibres are configured as a plurality of glass fibres.

5. The fuel filter according to claim 1, wherein the plurality of fibres include at least one of plastic, polyester, cellulose, and metal.

6. The fuel filter according to claim 1, wherein the fuel filter is configured as a diesel fuel filter.

7. The fuel filter according to claim 2, wherein the coalescer is arranged downstream of the particle filter relative to the throughflow direction.

8. A method for producing a coalescer for a fuel filter, comprising: producing a coalescer material via at least one of weaving, knitting, and a nonwoven method; orienting a plurality of fibres of the coalescer material in an essentially parallel manner to produce a coalescer web; and at least one of: producing a coalescer mat via (i) cutting the coalescer web into a plurality of individual cut-to-length coalescer web sections, the coalescer web cut in a direction extending transversely to a fibre longitudinal direction, (ii) turning the plurality of cut-to-length coalescer web sections 90°, and (iii) sticking the plurality of cut-to-length coalescer web sections to one another laterally; and producing a bellows via folding the coalescer web in a zigzag-shaped manner.

9. The method according to claim 8, wherein the method includes producing the coalescer mat, and the method further comprises sticking ends of the coalescer mat together to form the coalescer mat into a closed ring in which the plurality of fibres are oriented essentially in a radial direction of the closed ring.

10. The method according to claim 8, wherein: the method includes producing the bellows; and producing the bellows includes pressing the bellows on block.

11. The method according to claim 10, wherein: the plurality of fibres includes a plurality of bicomponent fibres; and the method further comprises sticking together individual folds of the bellows via heating the plurality of bicomponent fibres.

12. The method according to claim 11, wherein: each of the plurality of bicomponent fibres includes a temperature-stable core surrounded by a plastic casing; and heating the plurality of bicomponent fibres includes melting the plastic casings of the plurality of bicomponent fibres.

13. The method according to claim 11, further comprising applying a hydrophilic coating onto a raw side of the bellows.

14. The method according to claim 8, wherein orienting the plurality of fibres includes carding the plurality of fibres such that at least 50% of the plurality of fibres are oriented parallel to one another.

15. The method according to claim 8, wherein orienting the plurality of fibres includes combing the plurality of fibres such that at least 80% of the plurality of fibres are oriented parallel to one another.

16. A fuel filter, comprising: a housing; a coalescer arranged in the housing, the coalescer configured to separate out water contained in a fuel flowable through the coalescer in a throughflow direction; the coalescer including a coalescer material for coalescing water; the coalescer material including a plurality of fibres; and wherein at least 50% of the plurality of fibres are oriented at an angle of less than 45° relative to the throughflow direction.

17. The fuel filter according to claim 1, wherein the plurality of fibres includes a plurality of bicomponent fibres each including a temperature-stable core surrounded by a plastic casing.

18. The fuel filter according to claim 1, wherein at least 80% of the plurality of fibres are oriented parallel to one another.

19. The fuel filter according to claim 1, wherein at least 50% of the plurality of fibres are oriented at an angle of less than 45° relative to the throughflow direction.

20. The fuel filter according to claim 2, further comprising a filter element including the coalescer and the particle filter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] There are shown, respectively schematically,

[0023] FIG. 1 shows a sectional illustration through a fuel filter according to the invention,

[0024] FIG. 2 shows a sectional illustration through a coalescer according to the invention,

[0025] FIGS. 3 and 4 show a method for the production of a fuel filter according to the invention.

DETAILED DESCRIPTION

[0026] According to FIG. 1, a fuel filter 1 according to the invention, which can be for example a diesel fuel filter and is used in an internal combustion engine of a motor vehicle, has a housing 2 in which a particle filter 3 is arranged. There is arranged downstream of the particle filter 3 a coalescer 4 for separating out water 6 contained in fuel 5, wherein the coalescer 4 comprises at least one layer of a coalescer material 7 that is suitable for the coalescence of water 6 (cf. also FIG. 2). Purely theoretically, the coalescer 4 could undertake not only the coalescence function, but also a filtration, so that in this case no separate particle filter 3 would be provided. The particle filter 3 and the coalescer 4 are flowed through here in a throughflow direction 8. According to the invention, the coalescer material 7 now has fibres 9 whose primary orientation is oriented essentially parallel to the throughflow direction 8. In other words, this means that a longitudinal direction of the individual fibres 9 is oriented predominantly parallel to the throughflow direction 8. A primary orientation of the fibres 9 is not present here only when all the fibres 9 run in a parallel manner, but also already when the running direction of over 50 percent of the fibres 9 have an angle of preferably less than 45 degrees to a direction which then represents the primary orientation. Preferably, even over 80 percent, in particular even over 90 percent, of the fibres 9 have an angle of less than 45 degrees to the throughflow direction 8. Through the fibre orientation or respectively orientation in throughflow direction 8 selected according to the invention, individual water drops 6′ can adhere to the surface of the fibres 9 for a long time and thereby agglomerate and form larger drops. By the fibres 9, oriented in throughflow direction 8, in addition a pressure loss in the coalescer material 7 falls, which has a positive effect on the operation of the fuel filter 1.

[0027] The particle filter 3 or respectively the coalescer 4 can be configured in a ring-shaped manner in cross-section (cf. FIGS. 1, 3 and 4). In addition, the coalescer 4 and the particle filter 3 can be combined in a filter element 17.

[0028] The fibres 9 preferably have here a diameter D between 1 μm and 30 μm and hereby influence the agglomeration effect in a particularly favourable manner. The fibres 9 of the coalescer material 7 can be configured for example as glass fibres, but also as plastic fibres, in particular polyester fibres, cellulose fibres or metal fibres. The fibre orientation can be realized here via specific production methods, thus for example the fibres 9 are deposited in machine direction onto a screen carrier and are subsequently further oriented in a targeted manner via a so-called comb method (carding) in machine direction (y-direction). Subsequently, the thus produced coalescer material 7 can be folded and laid on block, so that a bellows 13 results, in which the fibres 9 are oriented with regard to their longitudinal direction, i.e. their primary orientation, essentially parallel to the throughflow direction 8.

[0029] Particularly preferred methods for the production of the coalescer 4 are described below, in which the coalescer material 7 is produced by means an aerodynamic nonwoven method, for example meltblown or spunbond methods, or of a hydrodynamic nonwoven method (wetlaid nonwovens). The fibres 9 of the coalescer material 7 which are produced here are deposited here in a parallel manner or, with a multidirectional deposition, are additionally carded, in particular combed, and thus oriented essentially parallel to one another. The coalescer material 7 can also be produced by means of knitting, warp-knitting or weaving, wherein a fibre orientation in Z-direction is provided, for example in an analogous manner to other applications, such as for example cleaning cloths, hand towels, etc. In principle, all nonwovens can be used. By the carding it is achieved that the fibres 9 are arranged essentially parallel to one another. Essentially parallel is intended to mean here that at least 50 percent of the fibres 9, preferably 80 percent or even 90 percent of the fibres 9 are oriented parallel to one another or respectively parallel to a primary orientation. Thereby, a coalescer web 10 is produced with fibres 9 running in machine direction (y-direction).

[0030] These thus produced coalescer webs 10 can then be further processed as follows:

[0031] Variant 1 (cf. FIG. 3): Cutting to length the coalescer web 10 transversely to the fibre longitudinal direction (y-direction) into individual coalescer web sections 11, wherein the cut-to-length coalescer web sections are turned through 90° and stuck laterally to one another, so that a coalescer mat 12 results, or

[0032] Variant 2 (cf. FIG. 4): Orienting of the fibres 9 in y-direction, i.e. optimizing of the combing with subsequent folding (for orienting in z-direction).

[0033] In Variant 2, the produced coalescer web 10 is folded in an alternating manner about an x-axis and thereby a zigzag-shaped folded web is produced, in which the fibre longitudinal direction follows the zigzag shape. Subsequently, this folded web is cut to a bellows 13 and for example stuck into a coalescer frame, wherein an additional on-block pressing of individual folds 14 can take place, in order to be able to bring about an almost parallel orientation of the fibres 9.

[0034] The bellows 13 can be heated here, wherein bicomponent fibres are used as fibres 9 which, on heating, bring about a sticking together of individual folds 14 of the bellows 13.

[0035] It is essential that the fibres 9 are flowed against in longitudinal direction. In the previously mentioned Variant 2, it is crucial that the folds 14 stand closely to one another, so that the fluid can not flow into the fold 14, but rather is forced to flow through the fold 14 longitudinally and thus also the fibres 9 are flowed against in longitudinal direction.

[0036] In Variant 1 the produced coalescer web 10 is cut to length, i.e. cut off, and the cut-to-length coalescer web sections 11 are turned through 90° and are stuck to one another laterally at sites 15, so that a coalescer mat 12 results (cf. FIG. 3). Here, several parallel fibres 9 in z-direction are from an individual fibre 9 in y-direction in the original coalescer web 10. Subsequently the coalescer mat 12 is rolled to a cylindrical ring filter and is stuck together at the ends. The fibres 9 lie here in radial direction (cf. FIG. 1, 3). Purely theoretically, it is of course also conceivable that the coalescer material 7 in the later coalescer 4 is configured as a polygon.

[0037] The coalescer webs 10 can also have a respectively outer layer of a hydrophobic spunbond or bico-lattice (bicomponent lattice) and an inner layer of a coalescer nonwoven. On heating, the bico-lattices melt and bring about a sticking together of the individual folds 14 in a coalescer 4 produced according to Variant 2. Such bico-fibres have a more temperature-stable core and a casing of a plastic with a lower melting point, so that with a heating the casing melts and the individual fibres 9 or respectively folds 14 stick together with one another and thereby a stabilizing is brought about, the core, however, remains stable.

[0038] Furthermore, the applying of a hydrophilic coating onto a raw side of the bellows 13 is also possible. If the coalescer material 7—as described above—is to be coated with a (hydrophobic) spunbond, it is advantageous to arrange a hydrophilic coating on the onflow side, so that the water drops 9 can penetrate more easily into the fold 14. The hydrophobic spunbond is then between the folds 14, which is intended to prevent the exiting of the drops 9 out of the folds 14.