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.

Abstract: A fuel filter device for an internal combustion engine may include a water separator through which a fuel is flowable. To separate water contained in the fuel, the water separator may include a porous and hydrophilic membrane, which may include or be made of polymeric hollow fibers and which may be formed for cross-flow filtration of the fuel. A material of the hollow fibers may be hydrophilized via polyvinylpyrrolidone (PVP). The fuel filter device or the water separator may have a hydrophobic membrane for filtering residual fuel from the water separated via the hydrophilic membrane.

Abstract: A filter medium for fuels may include a first layer of a filter material and a second layer of a filter material. A contact angle of water on the first layer of filter material may be greater than 90°. A contact angle of water on the second layer of filter material may be greater than 90°. The first layer of filter material may have an average pore diameter that is greater than an average pore diameter of the second layer of filter material.

Abstract: A separator for a separator device, for example a final separator for a final separator device for separating water from a liquid such as oil and/or fuel, may include a filter body including at least one filter material through which the liquid can flow. The filter body may have a first side and a second side. A nanofibre layer may be disposed on the first side in at least one region. The nanofibre layer may be configured hydrophobic. According to an implementation, the nanofibre layer is treated to produce the hydrophobic property. The filter body may have a porosity on the first side that is smaller than on the second side.