Liquid Filter for Separating Water and/or Particle Filtration of a Fuel and/or Aqueous Solution, in Particular a Urea Solution, and/or Water

Abstract

A liquid filter for water separation and/or particle filtration of a fuel and/or aqueous solution, in particular a urea solution, and/or water, in particular in a motor vehicle, is described. The liquid filter has at least one filter and/or coalescer medium that is made of a non-woven fabric that has fibers and/or threads having elementary silver.

Claims

1. A liquid filter (1) for water separation and filtration of an aqueous solution, comprising: at least one filter of a filter medium; and/or a coalescer medium that is made of a nonwoven fabric, the nonwoven fabric comprising fibers and/or threads having elementary silver.

2. The liquid filter according to claim 1, wherein the fibers and/or threads made of elementary silver are embedded into the filter medium and/or coalescer medium.

3. The liquid filter according to claim 1, wherein the liquid filter has a filter element (6) that comprises the filter medium and/or coalescer medium; wherein the liquid filter is exchangeably arranged into a filter housing (2) of the liquid filter (1).

4. The liquid filter according to claim 1, wherein the filter housing (2) incoudes: a water collection chamber (10) for collecting water separated from the fuel, and a filter chamber (3), for cleaning the fuel; wherein the filter and/or coalescer medium is arranged in the filter chamber.

5. The liquid filter according to claim 1, wherein the filter and/or coalescer medium is embodied as a pleated filter medium that has at least one layer of non-woven fabric and that is arranged in the filter housing (2) in a star shape.

6. The liquid filter according to claim 1, wherein the filter element (6) is arranged in the filter housing (2) of the liquid filter (1) such that at least one filter and/or coalescer medium is exposed to a primary flow of a fuel to be filtered when the liquid filter (1).

7. The liquid filter according to claim 1, wherein the fibers and/or threads are made of elementary silver.

8. The liquid filter according to claim 1, wherein the non-woven fabric comprises at least 50 wt. % non-woven fabric fibers that are made of polymer plastic fibers and/or glass fibers.

9. The liquid filter according to claim 1, wherein a mean fiber diameter of the silver fibers is between 300 nm and 20 μm.

10. The liquid filter according to claim 1, wherein the filter and/or coalescer medium has at least one other biofunctional coating and/or a granulate that contain(s) silver.

11. The liquid filter according to claim 1, wherein the coalescer medium and/or the filter medium is made of the non-woven material.

12. The liquid filter according to claim 1, wherein the liquid filter (1) is arranged in a primary flow of a fuel line and/or a line for a urea solution, arranged in a motor vehicle; and wherein the primary flow is conducted onto the filter and/or coalescer medium.

13. The liquid filter according to claim 12, wherein the liquid filter (1) is arranged in a line of a water injection system of an internal combustion engine; wherein the liquid filter (1) is arranged downstream of at least one water reservoir and upstream of at least one injection nozzle and/or injection valve of the water injection system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention shall be explained in greater detail in the following using a specific exemplary embodiment and the figures. The figures are as follows.

[0028] FIG. 1 depicts a filter element having a plurality of filter and/or coalescer media for use in an inventive liquid filter for filtering a fuel in an internal combustion engine; and,

[0029] FIG. 2 depicts an inventive liquid filter having the filter element from FIG. 1.

DETAILED DESCRIPTION

[0030] FIG. 2 is a longitudinal section of a liquid filter 1 for filtering fuel, preferably diesel fuel, and/or a urea solution. The liquid filter may preferably be used in an internal combustion engine. This liquid filter may be employed inter alia as a water separator or as a particle filter for separating particles from a liquid medium. The structure of the liquid filter itself is known in detail from WO2015/018785, referenced in its entire scope hereby with respect to the construction of a liquid filter in the context of the present invention.

[0031] The liquid filter 1 comprises, inter alia, a filter housing 2 and filter element 6 arranged therein and depicted in detail in FIG. 1. The annular filter element 6 comprises a plurality of filter and/or coalescer media. A first filter medium is embodied as filter bellows 12 and the liquid to be filtered flows through it radially from outside to inside. Consequently the cylindrical interior in the filter element 6 forms a dean chamber 7 from which the cleaned liquid is axially removed. Inserted in the clean chamber 7 of the filter element 6 is a center or support tube 8 that preferably comprises plastic and that supports the filter medium or media of the filter element 6, imparting stability thereto. The center tube 8 lines the clean chamber 7.

[0032] On the radially interior side of the filter means of the filter element 6, the filter medium 6 has a coalescer element 9 with a coalescer medium. Finely distributed water droplets in the fuel agglomerate on the coalescer element 9 so that they become larger droplets. These water droplets, which are contained e.g. in the diesel fuel, bond to the coalescer medium of the coalescer element 9, creating larger drops; they coalesce. The volume may be further increased by downstream coalescer elements. The flow is guided such that large drops are separated from the fuel solely by means of gravity.

[0033] Disposed in the lower region, near the bottom, in the filter housing 2 is a water collection chamber 10 in which water is collected that is separated during the filtration of the liquid. The collected water may be removed via an opening on the bottom and a valve out of the water collection chamber 10 in the filter housing.

[0034] Inserted into the clean chamber 7 is a water separator screen 11 that is embodied as a hollow cylinder and that has an outer diameter that is smaller than the inner diameter of the center tube 8 so that an interposing annular chamber 4 is formed as part of the clean chamber 7. The water separator screen 11 may preferably have a water separating screen fabric as an additional filtration stage and as an additional barrier for any water droplets still present. The water separator screen 11 extends axially, like the center tube 8, across the entire length of the clean chamber 7 or filter element 6. The separated water droplets are removed via the lower axial end face of the clean chamber 7 into the water collection chamber 10.

[0035] The wall of the water separator screen 11 has a plurality of through-holes via which the cleaned fuel can flow radially inward into the interior of the water separator screen 11 out of the annular space between center tube 8 and water separator screen 11. Then the cleaned fuel, from which the water droplets have been removed, is removed axially via the axially upper end face of the clean chamber 7, which is in flow connection with the outlet line 5.

[0036] In FIG. 1 the filter element 6 is depicted in a perspective elevation, with a partial cut-away. The filter bellows 12 is enclosed on each end face by an end disk 13, 14.

[0037] It is functionally preferred that the liquid filter 1 has a three-stage structure. The pleated bellows 12 is primarily a particle filter and forms the first stage of the fuel cleaning. It removes particulate impurities from the fuel. The one or more coalescer elements 9 enlarge the water drops in the fuel in the second filtration stage. The water is separated using a hydrophobic barrier in the third stage. This third stage is formed by the water separator screen 11.

[0038] The water collection chamber 10 may be checked by a sensor and emptied when it is sufficiently full.

[0039] The filter elements with the filter and/or coalescer media, which form the first and second stages, may be subject to microbiological contamination and are preferably part of the aforesaid filter element 6. When too soiled, the latter may be exchanged.

[0040] In one preferred variant, the filter element 6 is provided as an exchangeable part in the liquid filter.

[0041] One or more of the aforesaid filter elements, that is, filter bellows 12 and/or coalescer element 9, are made of a single or multi-layer filter and/or coalescer medium that is made of a non-woven fabric and that has, in addition to the non-woven fabric fibers, silver fibers, that is, fibers that have elementary silver or comprise elementary silver. Continuous filaments may also be provided for the silver fibers. However, silver fibers having a mean fiber length of 5 μm to 3 cm are preferred. The mean fiber length may be determined statistically using microscopy.

[0042] Alternatively or in addition to the silver fibers, the nonwoven fabric may also have silver threads, that is, threads that comprise elementary silver or are coated with elementary silver.

[0043] The non-woven fabric of the filter medium is preferably a non-woven fabric that is chemically resistant to the fuel being used, especially diesel fuel.

[0044] The non-woven fabric may preferably comprise non-woven fabric fibers that are made of cellulose, polybutylene terephthalate, polyimide, and/or polypropylene, and/or glass fibers. The fibers are present in the non-woven fabric at greater than 50 wt. %, particularly preferred at greater than 80 wt. %.

[0045] As described in the foregoing, in addition to conventional non-woven fabric fibers, the non-woven fabric has fibers made of elementary silver or fibers that are coated with elementary silver. These silver fibers are distributed in the non-woven fabric and are present in the non-woven fabric at less than 50 wt. %, preferably at less than 20 wt. %.

[0046] Preferably the mean fiber diameter of the silver fibers may be between 300 nm and 20 μm, particularly preferably between 800 nm and 15 μm. The mean fiber diameter may be determined according to DIN 53811:1970-07.

[0047] The non-woven fabric may preferably be produced in the meltblown, spunbond, or wet-lay process. The silver fibers may preferably be worked into the filter and/or coalescer medium during production. The medium may comprise 100% silver fibers or also just a small portion thereof. A second fiber type may be full synthetic continuous fibers or even individual fibers with a finite length.

[0048] The filter medium may be constructed with a single layer and/or with multiple layers, wherein preferably at least one material layer is formed from the aforesaid silver fiber-containing non-woven fabric.

[0049] The filter element 6 is also preferably arranged in the primary flow of the fuel and/or urea solution.

[0050] The silver fibers worked into the non-woven fabric prevent or reduce at least the microbiological growth in the fuel or urea solution with which the filter medium is wetted following initial proper use. Thus a biofilm or bio-slime that can clog the filter medium is prevented from forming.

[0051] This tendency for microbiological growth is particularly pronounced during lengthy standing times, multiple recirculations of the fuel or urea solution, when there are frequent cold starts, and/or when short distances are driven.

[0052] The silver fibers and/or silver threads are preferably worked into the non-woven fabric. Thus silver threads, for instance, may be output onto a substrate through a second nozzle during a meltblown or spunbond process, while polymer fibers are applied through a first nozzle.