Abstract: The invention relates to a corrugated or pleated flat material with a plurality of pleats or corrugations that run parallel to one another and successively define a pleat or corrugation peak and a pleat or corrugation valley, the peak and valley being connected to one another by way of a pleat or corrugation flank, wherein a fluid can flow through the flat material and the flat material has at least one deformable functional layer which rests on a supporting layer in the direction of throughflow of the fluid, said supporting layer comprising a supporting fabric, the functional layer allowing foreign substances to be removed from or delivered to the fluid. In order to develop the flat material in such a way that it has greater mechanical load-bearing capacity and lower resistance to throughflow, it is proposed according to the invention that the supporting fabric is deformable and comprises a twill weave.

Abstract: The invention relates to a corrugated or pleated flat material with a plurality of pleats or corrugations that run parallel to one another and successively define a pleat or corrugation peak and a pleat or corrugation valley, the peak and valley being connected to one another by way of a pleat or corrugation flank, wherein a fluid can flow through the flat material and the flat material has at least one deformable functional layer which rests on a supporting layer in the direction of throughflow of the fluid, said supporting layer comprising a supporting fabric, the functional layer allowing foreign substances to be removed from or delivered to the fluid. In order to develop the flat material in such a way that it has greater mechanical load-bearing capacity and lower resistance to throughflow, it is proposed according to the invention that the supporting fabric is deformable and comprises a twill weave.