Patent ID: 8584868

Claim:
A filter medium for removing particles from a fluid flow, in particular particles from a fuel flow of an internal combustion engine, comprising: a fine filter layer; a prefilter layer covering and joined to an upstream surface of said fine filter layer, said upstream surface relative to a flow-through direction of said filter medium; a first support layer arranged at and secured to a unfiltered side of said prefilter layer; a second support layer arranged at and secured to a filtered side of said fine filter layer, wherein said support layers are operable to absorb longitudinal or transverse forces under tensile or pressure loading of said layers, wherein one of said support layers is a transverse force absorbing layer having a greater bending stiffness in a transverse direction relative to the other support layer, and wherein the other one of said support layers is a longitudinal force absorbing layer having a greater bending stiffness in a longitudinal direction relative to the transverse force absorbing support layer, wherein the support layers are comprised of a polymer selected from the set: PBT, PA, PP or PES having a thickness between 0.3 to 1.2 mm and a weight per surface area in the range of 50 to 200 g/m2, wherein the filter layers and support layers are secured to each other by means of thermal calander, ultrasound, powder or spray adhesive, wherein at least one of the support layers is embodied in the form of a grid that has crossing threads, wherein the crossing threads define a thread angle between a first thread and a second thread crossing said first thread, wherein a first one of said support layers absorbing transverse forces is a grid having a thread angle of between 80 to 100 degrees, wherein a first one of said support layers absorbing longitudinal forces is a grid having a thread angle of between 40 to 80 degrees, wherein the longitudinal direction bisects the thread angle of the transverse force absorbing support layer, wherein the longitudinal direction bisects the thread angle of the longitudinal force absorbing support layer.