Filter media and manufacturing method thereof

Abstract

The present disclosure relates to filter media containing antimicrobial compounds, methods for making the filter media, filter elements, filter systems, and methods for filtering water in the combustion chamber of an internal combustion engine using the filter media.

Description

[Technical Field]

[0001] The present disclosure relates to filter media containing antimicrobial compounds, methods for making such filter media, filter elements, filter systems, and methods for filtering water in the combustion chamber of an internal combustion engine using such filter media. [Background technology]

[0002] In the development of new engine generations, there is currently an increasing focus on reducing the emission of polluting exhaust gases such as nitrogen oxides (NOx). One possible technical solution to reduce NOx in exhaust gases is to inject water into the gas / air mixture in the combustion chamber of the engine. Injecting water into the combustion chamber actually reduces the temperature of the exhaust gases as well as pre-ignition. However, the use of water also presents several problems related to the presence of impurities in the water. These impurities can cause damage to components located inside the cylinder and, in addition, can promote the growth of microbial species, such as bacteria, algae, fungi, or other microorganisms.

[0003] Patent application DE102017006462A1 (hereinafter DE'462) proposes a filter medium comprising a grid as a support layer and a meltblown layer as a filtration layer, with both the grid and the meltblown layer being impregnated or coated with an antibacterial material. However, this medium exhibits several drawbacks. First, the presence of the grid increases the cost of the medium. Furthermore, the meltblown layer must have a high mass and thickness, which not only increases the cost but also reduces the number of pleats in the filter. As is well known, the number of pleats affects the filtration surface, which in turn affects the service life, dust retention capacity, and differential pressure.

[0004] Therefore, there remains a need for a filter media that exhibits superior performance in terms of efficiency, dust holding capacity, strength, service life, and antimicrobial activity, which can be used to filter water injected into the combustion chamber. Additionally, there remains a need for a filter media that is less expensive than previously available filter media for filtering the water in the combustion chamber of an internal combustion engine.

[0005] Description of the Disclosure It is an object of the present disclosure to provide a filter medium that exhibits superior performance in terms of efficiency, dust holding capacity, strength, differential pressure, and service life, as well as antimicrobial activity. It is a further object of the present disclosure to provide a filter medium for filtering water in the combustion chamber of an internal combustion engine that is less expensive than previously available filter media.

[0006] The filter media of the present disclosure is particularly suitable for filtering water in the combustion chamber of an internal combustion engine. The filter media according to the present disclosure comprises: (i) a first meltblown layer; and (ii) a second spunbond layer; wherein at least one of the first and second layers comprises at least one antimicrobial compound.

[0007] The first meltblown layer can be manufactured according to known production methods. Suitable polymers for the first meltblown layer include, for example, polyolefins (e.g., polypropylene), polyesters (e.g., polyethylene terephthalate and polybutylene terephthalate), and polyamides. Preferably, the meltblown layer comprises polybutylene terephthalate (PBT). Additives such as crystallization promoters and dyes can also be mixed into the polymer.

[0008] The average fiber diameter of the first meltblown layer is 0.5 to 10 μm, preferably 0.5 to 5 μm, and more preferably 0.5 to 2 μm, and particularly preferably 0.8 to 1.4 μm. The basis weight of the first meltblown layer is 30-95g / m 2 and preferably 40 to 90 g / m 2 , and more preferably 45 to 80 g / m 2 is. The thickness of the first meltblown layer is 0.05 to 0.80 mm, preferably 0.1 to 0.6 mm, and more preferably 0.2 to 0.5 mm (measured at a pressure of 10,000 Pa (0.1 bar) in accordance with DIN EN ISO534:2012).

[0009] Additional meltblown layers may also be present in the filter media. These may be the same as the first meltblown layer or may have different characteristics in terms of polymer composition, thickness, fiber diameter, and basis weight.

[0010] The second spunbond layer can be manufactured according to known manufacturing methods. Suitable polymers include, for example, polyolefins (e.g., polypropylene), polyesters (e.g., polyethylene terephthalate and polybutylene terephthalate), polyamides, or mixtures thereof. Preferred polymers are polyesters, such as polybutylene terephthalate (PBT) and polyethylene terephthalate (PET).

[0011] Preferably, the second spunbond layer comprises bicomponent fibers. An example of a preferred multicomponent fiber is a PET / CoPET bicomponent fiber, which has a core-sheath structure.

[0012] The average fiber diameter of the second spunbond layer is 5 to 40 μm, preferably 10 to 30 μm, and more preferably 15 to 20 μm. The basis weight of the second spunbond layer is 40 to 130 g / m 2 and preferably 50 to 110 g / m 2 , and more preferably 60 to 90 g / m 2 is. The thickness of the second spunbond layer (measured in accordance with DIN EN ISO534:2012 at a pressure of 10,000 Pa (0.1 bar)) is 0.09 to 0.70 mm, preferably 0.10 to 0.50 mm, and more preferably 0.18 to 0.40 mm.

[0013] A third spunbond layer may also be present in the filter media of the present disclosure, the polymer type and average fiber diameter of the third spunbond layer being similar to those described above for the second spunbond layer.

[0014] The basis weight of the third spunbond layer is 5 to 40 g / m 2 and preferably 10 to 30 g / m 2 , and more preferably 15 to 25 g / m 2 is. The thickness of the third spunbond layer (measured according to DIN EN ISO534:2012 at a pressure of 10,000 Pa (0.1 bar)) may be 0.08 to 0.40 mm, preferably 0.09 to 0.30 mm, and more preferably 0.10 to 0.20 mm.

[0015] The third spunbond layer, if present, will be located on the side of the meltblown layer opposite the second spunbond layer and will act as a protective layer for the meltblown layer. When used in a filter element, the filter media is used such that the direction of fluid flow through the filter media is through the first meltblown layer or, if present, the third spunbond layer, with the outflow side being the second spunbond layer.

[0016] At least one layer of the filter media contains an antimicrobial compound. "Antimicrobial compound" refers to any compound that inhibits the development of microbial species, such as bacteria, algae, and / or fungi. The at least one antimicrobial compound may be selected from the group consisting of metals, pyrithione metal salts, quaternary ammonium salts, polyelectrolytes, polymeric biguanide derivatives, or mixtures thereof. The metals and metals of the pyrithione metal salts are selected from the group consisting of copper, zinc, and silver, or mixtures thereof. The metals may be used in the form of nanoparticles, preferably silver nanoparticles. The quaternary ammonium salts are selected from the group consisting of benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dophanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, and domiphen bromide. The antimicrobial compound may also be selected from the group of polymeric compounds, for example, polyelectrolytes such as polycations or polyanions, salts thereof, or the group of polymeric biguanide derivatives, for example, poly(hexamethylene biguanide) hydrochloride. Preferably, at least the antimicrobial compound comprises a biguanide derivative.

[0017] The at least one layer containing the at least one antimicrobial compound may be impregnated or coated with the antimicrobial compound, or the at least one antimicrobial compound may be added to the polymeric material before it is processed into the meltblown and / or spunbond layers.

[0018] The antimicrobial compound may be applied using known techniques, such as spraying, dipping, roller application, foam application, or dusting. A saturated size press or other conventional means may be used, such as a curtain coater, metered press coater, foam bonder, grabber roll, dip and nip, doctor transfer roll, rod coater, and spray coater. When the antimicrobial compound is applied in liquid form (e.g., by dipping), the components are mixed in a solvent. Preferred solvents are water, organic solvents, or mixtures thereof. Among the organic solvents, mention may be made of alcohols such as methanol or ethanol. Preferably, the antimicrobial compound is applied by a foulard dipping technique.

[0019] Preferably, the layer containing the antimicrobial compound is the first meltblown layer. More preferably, only the first meltblown layer contains the at least one antimicrobial compound. In a preferred embodiment, the first meltblown layer is coated with the at least one antimicrobial compound, and more preferably, the coated first meltblown layer is the only layer containing the antimicrobial compound.

[0020] If not just one layer, such as the first meltblown layer, contains the antimicrobial compound, but multiple layers (e.g., two or three layers, depending on the type of filter media, such as the second and third spunbond layers) contain such a compound, the multiple layers may differ with respect to the type of antimicrobial compound used in the layers (i.e., whether the same antimicrobial compound is used in the multiple layers or different types of antimicrobial compounds are used), as well as the amount applied, the method of application of the antimicrobial compound (coating, dispersed within the fibers of the layer, etc.).

[0021] The filter media according to the present disclosure exhibits an initial efficiency of at least 85%, preferably at least 90%, and more preferably at least 95% for 4 μm particles, as measured at 200 cm using A3 media test dust (ISO 12103-1, PTI Powder Technology Inc.) in accordance with ISO 19438:2003(E). 2 The measurements were performed on a flat sheet of 100 ml of water at a flow rate of 0.71 L / min using a BUGL 100. The filter media according to the present disclosure has a filter resistance of at least 1.3 g / 200 cm at a pressure drop of 70,000 Pa (0.7 bar). 2 , preferably at least 1.5 g / 200 cm 2 , more preferably at least 1.8 g / 200 cm 2 of dust holding capacity (measured in accordance with ISO 19438:2003, but on a flat sheet).

[0022] The initial efficiency of the filter element was also tested in accordance with ISO 19438:2003(E). The initial efficiency levels are at least 85% for 4 μm particles, at least 90% for 5 μm particles, at least 99.9% for 10 μm particles, and at least 99.95% for 20 μm particles. Similar efficiency levels are achieved by using microfiltered water instead of the test liquid specified in the ISO 19438:2003(E) standard when testing the filter element. The specific dust retention capacity is at least 75 g / m at a pressure drop of 30,000 Pa (0.3 bar), as measured in accordance with ISO 19438:2003(E). 2 is.

[0023] Preferably, the diameter of the "many pores" of the filter medium is 5 to 30 μm, preferably 10 to 25 μm, according to the pore size measurement described below. More preferably, the diameter (size) of the "many pores" is 7 to 15 μm. Preferably, the maximum pore size (diameter) is 15 to 40 μm, more preferably 15 to 30 μm.

[0024] Surprisingly, it has been found that the antimicrobial compounds of the filter media not only exhibit excellent antimicrobial activity, but are also very stable over long periods of time, making them particularly suitable for water filtration in the compartments of combustion engines. The antibacterial activity of the filter media was tested according to DIN EN ISO 20743:2013. To adapt this standard for the purposes of these studies, deviations were made from the standard and the microorganisms used were Pseudomonas aeruginosa and Stenotrophomonas maltophilia. The filter media had an antibacterial activity of at least 2 log, preferably at least 4 log, after 24 hours of incubation (i.e., LRF >2 and preferably >4), which corresponds to 99.99% or greater inactivation.

[0025] The effects of pH (i.e., pH 5, 7, and 9) and temperature (5, 30, and 80°C) on the release characteristics of the coatings were also tested. The media were stable at different pHs and temperatures, even after three months, and no significant release of the coatings was detected. For example, the coating containing silver ions showed a silver ion release of less than 60 μg / L at temperatures of 5, 30, and 80°C and pH of 5, 7, and 9. The release of ammonium ions at temperatures of 5°C and 30°C was less than 0.643 mg / L. The bacteria did not affect the release behavior. The test conditions are described in the corresponding sections.

[0026] The filter media may be pleated into filter elements with various pleats depending on the size of the filter element. The amount of the at least one antimicrobial compound in the filter medium is typically 0.0001% to 2.0000% by weight, preferably 0.001% to 1.8000% by weight, and more preferably 0.01 to 1.5% by weight, based on the total weight of the filter medium.

[0027] The hydrophobicity of the filter media is 0. A hydrophobic material is water-repellent. Water remains on the surface of the material in the form of droplets, even after a long period of time. To measure this, the water absorption capacity of the substrate is determined. The hydrophobicity can be determined by applying droplets of different surface tensions. Droplets of test liquid are applied from a dropper bottle to the material being tested. After a dwell time of 1 minute, it is observed whether the test liquid mixture remains as droplets on the material without penetrating. The test liquid is applied in increasing increments. The number of droplets that remain on the material for 1 minute without penetrating is used as the measurement. In this example, the test liquid was water (i.e., the value is 0).

[0028] The filter media can be manufactured by joining the spunbond layer and the meltblown layer. Any known method can be used for joining, such as needling, sputtering, heat treatment (i.e., calendaring, ultrasonic welding), and chemical treatment (i.e., adhesives). Preferably, the meltblown layer and the spunbond layer are joined by a point calendaring method.

[0029] The present disclosure also relates to a filter element and a filter system including the filter media of the present disclosure. The filter element may include first and second end plates with the filter media disposed therebetween. The filter media may be folded, for example, in a zigzag pattern and disposed between the end plates. The filter element may have a radial flow pattern from the outside to the inside or from the inside to the outside. In addition, the filter element may have at least one check valve to prevent previously filtered water from flowing back through the filter element. The present disclosure also provides a filter system including at least one filter element, a filter element housing, and a filter housing cap. The filter element is installed within the filter element housing. When the filter element is properly installed within the housing, the filter element separates the untreated side from the pure side, so that liquid must be filtered through the filter media of the filter element.

[0030] The filter media of the present disclosure may be used to filter water in the combustion chamber of an internal combustion engine.

[0031] With the above in mind, the present disclosure provides, inter alia, the following preferred embodiments. I. A filter medium comprising: (i) a first meltblown layer; and (ii) a second spunbond layer; wherein at least one of the first and second layers comprises at least one antimicrobial compound. II. The filter media of I, wherein the at least one antimicrobial compound is selected from the group consisting of a metal, a pyrithione metal salt, a quaternary ammonium salt, a polyelectrolyte, a polymeric biguanide derivative, or a mixture thereof. III. The filter media of any one of I-II, wherein only the meltblown layer comprises the at least one antimicrobial compound. IV. The filter media of any one of I-III, wherein both the first meltblown layer and the second spunbond layer comprise at least one antimicrobial compound. The antimicrobial compound may be the same or different in the two layers, and if the same antimicrobial compound is used, the layers may differ in this respect with respect to the amount of antimicrobial compound applied, the method of providing the antimicrobial compound to the layers, etc. V. The filter media of any one of I-IV, further comprising a third spunbond layer. VI. The filter media of any one of I-V, wherein the first meltblown layer, the second spunbond layer, and the third spunbond layer each contain at least one antimicrobial compound. The antimicrobial compound may be the same or different in the three layers, and if the same antimicrobial compound is used, the layers may differ in this respect with respect to the amount of antimicrobial compound applied, the method of providing the antimicrobial compound to the layers, etc. VII. The filter media of any of I-VI, wherein the first meltblown layer, the second spunbond layer, and the third spunbond layer are coated with the at least one antimicrobial compound. VIII. The filter medium of any one of I to VII, wherein the meltblown layer comprises polyester fibers. IX. The filter media of any of I-VIII, wherein the at least one antimicrobial compound is selected from the group consisting of quaternary ammonium salts and polymeric biguanide derivatives. X. The filter medium of any one of I to IX, wherein the amount of the at least one antimicrobial compound is 0.0001 to 2.0000 weight percent (wt%), based on the total weight of the filter medium. XI. The filter medium according to any one of I to X, wherein the first meltblown layer has a thickness of 0.05 to 0.8 mm. XII. The filter media of any one of I-XI, wherein the at least one antimicrobial compound is selected from the group consisting of zinc pyrithione, silver nanoparticles, quaternary ammonium salts, and poly(hexamethylene biguanide) hydrochloride. XIII. The filter media of any one of I-XII, wherein the at least one antimicrobial compound comprises or consists of a quaternary ammonium salt and poly(hexamethylene biguanide) hydrochloride. XIV. A filter element comprising the filter medium according to any one of I to XIII. XV. A filter element as described in XIV, comprising a first end plate, a second end plate, and a filter media capable of flowing radially therethrough. XVI. A filter element according to XIV or XV, comprising at least one valve, in particular a check valve. XVII. A filter system comprising a filter element according to any one of XIV to XVI, a filter element housing, and a filter housing cap. XVIII. Use of a filter medium according to any one of I to XIII for filtering water in the compartment of a combustion engine.

[0032] (Test Method) Pore ​​size: The pore size is measured with reference to DIN ISO 4003:1990. The sample is placed between an airtight clamp on the opening with an air supply and a connection to a pressure gauge (a U-tube with mm indicator). Each sample is tested with the top side facing up. A slight excess air pressure on the liquid is achieved by pouring denatured ethanol (100% ethanol with 1% MEK (methyl-ethyl-ketone) as a denaturant) onto the upper edge of the specimen holder (not directly onto the sample / about 4 mm deep). The air pressure is slowly increased (about 5 mm water gauge / second) until the first air bubbles are visible. The required air pressure level is read off the pressure gauge (mm water gauge). The surface tension of the ethanol (23°C) can be used to calculate the diameter of the largest pores ("Maximum Pore", "Maximum Pore Size", "Maximum Pore Diameter").

[0033] The air pressure was then further increased until the air reached the entire surface of the sample (10 cm 2 ) until the foam is evenly distributed but not foaming, and the "many pores" value is determined. The air pressure is read again and the relative pore diameter, i.e., the "many pore" diameter, is calculated. The "maximum pore size" and "number of pores" may be calculated using the following formulas as described above: TIFF2025533856000001.tif17170d=Pore diameter [μm] p = air pressure [mN / m 2 ] σ = surface tension of test liquid (e.g., ethanol) [σ of ethanol at 23°C = 21.330225 mN / m] α = contact angle of the area where the liquid and sample come into contact (Conversion: 1mm water level gauge = 98.07mN / m 2 )

[0034] ThicknessThe thicknesses mentioned in this disclosure are measured according to DIN EN ISO 534:2012-02, but using a test pressure of 10,000 Pa (0.1 bar).

[0035] Basis weight :Complies with DIN EN ISO 536:2012-1.

[0036] Initial efficiency and dust holding capacity of flat sheets conforms to ISO 19438:2003(E) (ISO12103-1, A3 intermediate test dust, PTI Powder Technology Inc.), 200cm 2 The results were determined using a sample size of 0.71 L / min, a BUGL 100, and a flow rate of 0.71 L / min. Initial efficiency and dust holding capacity of the filter element was determined in accordance with ISO 19438:2003(E).

[0037] The pressure drop across the filter element is in accordance with ISO 4020:2001. The pressure drop depends on the filter geometry and is <2500 Pa (25 mbar), 120 l / h, 4 cSt (<25 mbar @ 120 l / h @ 4 cSt) in accordance with ISO 4020:2001. The same results were obtained with distilled water (deviation from ISO 4020:2001).

[0038] Average Fiber Diameter : Determined using a scanning electron microscope (e.g., Phenom Fei) and diameter measurement software (e.g., Fibermetric V2).

[0039] Sampling: For nonwoven fabrics, at least five points across the web width are selected and analyzed.

[0040] record: 1. Sample Sputtering 2. Random image based on the optical image (without magnification), rasterize selected areas at a magnification of at least 500x (magnification depends on the sample and is chosen so that the fibers can be identified). 3. Determining fiber diameter by the "one click" method: each fiber must be detected once, and the measurement points detecting the fiber intersections do not represent the fiber diameter and must be manually removed.

[0041] 7.Calculation The mean value and fiber diameter distribution are evaluated using data obtained from Fibermetric V2 and Excel tables. For each point, at least 100 fiber diameters are recorded and the average value is calculated. The five average values ​​are then combined to form an average value, which is the average fiber diameter of the nonwoven fabric. Therefore, the average fiber diameter of the nonwoven fabric is calculated based on at least 500 fibers.

[0042] Antibacterial Testing The tests were carried out in accordance with DIN EN ISO 20743:2013. In order to adapt said standard for the purposes of this disclosure, deviations were made by using the microorganisms Stenotrophomonas maltophilia and Pseudomonas aeruginosa.

[0043] Preparation of inoculum: Inoculation was performed from a pre-culture, which was prepared before the start of the experiment. For this purpose, one or two growing colonies of the bacterial strain were transferred from an agar plate to 40 ml of medium (contained in a 250 ml baffled Erlenmeyer flask). The Erlenmeyer flask thus inoculated was incubated overnight at 30°C. Based on the optical density of this overnight culture, the cell number was determined using a calibration curve between cell number and optical density. According to the target concentration of the test batch, dilutions were made from this and the test batch was inoculated with the dilutions. For the investigation of antibacterial properties, the microbial concentrations of the test batches were approximately 10 6 ~10 7 CFU / ml was started.

[0044] According to the standard method, the tested samples had a mass of 0.4 g. Before testing, the samples were irradiated with UV light for at least 2 hours. Next, four sterilized media samples were placed in 50 mL Falcon tubes. In the next step, 50 μL of inoculum was applied to each sample, resulting in four Falcon tubes containing four samples and inoculated with 0.2 mL of inoculum. For hydrophobic samples, the microorganism application procedure was not possible because droplets would remain on the filter surface. For this reason, reference filter pieces were immersed in water ("watered") before use in the test. Additionally, the microorganisms were applied dropwise only and allowed to dry for 3-4 hours.

[0045] The t0 sample tube was reopened immediately after closing, and 20 mL of SCDLP medium was added. Each of the tubes was vortexed for 5 x 5 seconds, followed by shaking at a 30 cm arc for 30 seconds. The medium was then poured off and stored on ice. The solution obtained by shaking the microorganisms in this manner was then diluted, plated on LB medium, and evaluated using the plate count method. The tubes of the 24-hour samples were immediately placed in an incubation chamber at 30°C and after 24 hours of incubation at 30°C, the above procedure was again carried out.

[0046] Colonies were counted after 24 hours and 2 days. For the evaluation, it is essential to determine the cell count at time 0 and at the sampling time points. To calculate the logarithmic reduction factor, the Log 1000 is calculated from the applied CFU (colony forming units) and the CFUs spun out immediately after application or 24 hours after application. 10 The difference between the values ​​was calculated and the evaluation was carried out by presenting the logarithmic reduction factor (LRF).

[0047] Test conditions: -Incubation temperature is 30°C. -Sample: 4 strips per batch, mass 0.4g

[0048] Evaluation: The Log Reduction Factor (LRF) for each material, reference material, and test material is calculated using the number of bacteria applied and the number of surviving bacteria CFU (colony forming units) after 24 hours. LRF=log(CFU 適用した / CFU t ) LRF=logCFU 適用した logCFU t CFU t is the CFU after incubation time t.

[0049] Coating Release Test : For each batch, 8 ml of water was mixed with two test strips, each measuring 1 cm x 1.5 cm, in a 15 ml Falcon tube. At the beginning of the experiment, the Falcon tubes were set up and provided for the samples. These sample containers were no longer part of the experiment. The filter strips in water were incubated under different conditions, and after different test periods, samples were taken, treated, and measured. Studies of ion release were performed from the liquid phase at the beginning of the experiment and after approximately 7, 28, 60, and 90 days. The time course of possible washout should be recorded over a 3-month period. Analysis of anions was performed using ion chromatography (e.g., ICP-3000 or ICP-6000). [Example]

[0050] (Examples 1 to 3) The filter media shown in Table 1 were prepared. [Table 1] * It was determined according to the test conditions described in the patent. Exemplary media were coated using a foulard dipping technique. All three layers were coated. Test specimens of the media were coated with the antimicrobial compounds listed in Table 2. The amount of antimicrobial compound in the examples was 0.001 weight percent (wt%) based on the total weight of the filter media.

[0051] [Table 2] As can be seen from Table 2, all filter media according to the present disclosure have very good antimicrobial activity over time.

[0052] (Comparative Example 1) Same as Example 1, but without coating. The log reduction factor (LRF) for both bacteria showed negative values ​​after 24 hours.

Claims

1. 1. A filter media comprising: (i) a first meltblown layer; and (ii) a second spunbond layer; wherein at least one of the first and second layers comprises at least one antimicrobial compound.

2. 10. The filter media of claim 1, wherein the at least one antimicrobial compound is selected from the group consisting of a metal, a pyrithione metal salt, a quaternary ammonium salt, a polyelectrolyte, a polymeric biguanide derivative, or a mixture thereof.

3. The filter media of any of claims 1-2, wherein only the meltblown layer comprises the at least one antimicrobial compound.

4. The filter media of any of claims 1 to 3, further comprising a third spunbond layer.

5. The filter media of any of claims 1 to 4, wherein the meltblown layer comprises polyester fibers.

6. 6. The filter media of any of claims 1-5, wherein the at least one antimicrobial compound is selected from the group consisting of quaternary ammonium salts and polymeric biguanide derivatives.

7. The filter medium of any one of claims 1 to 6, wherein the amount of the at least one antimicrobial compound is 0.0001 to 2.0000 wt %, based on the total weight of the filter medium.

8. A filter element comprising the filter medium of any one of claims 1 to 7.

9. 10. The filter element of claim 8, comprising a first end plate, a second end plate, and a filter media capable of flowing radially therethrough.

10. 10. A filter element according to claim 8 or 9, comprising at least one valve, in particular a check valve.

11. A filter system comprising the filter element according to any one of claims 8 to 10, a filter element housing, and a filter housing cap.

12. Use of a filter medium according to any one of claims 1 to 7 for filtering water in the compartment of a combustion engine.

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