Installation element for a device for the treatment of a fluid, in particular a gas, in particular for the humidification, purification and/or cooling by means of a working fluid, comprising - at least a corrugated grid mat provided with - linearly extending valleys and ridges alternately arranged one beside the other, having flanks connecting the same, - two longitudinal edges substantially parallel to each other, as well as transversal edges extending transversely thereto, - linear first grid bars, substantially parallel to each other, which extend at angles different from 90° with respect to both the longitudinal edges and the transversal edges, and which extend at the bottom along the depressions and at the top along the protrusions, - wave-like second grid bars extending substantially parallel to the longitudinal edges and connected with the first grid bars at junctions arranged along imaginary, substantially linear junction lines, und - wave-like third grid bars, substantially parallel with respect to each other, and wave-like fourth grid-bars, also substantially parallel with respect to each other, said grid bars being connected with the first and second grid bars (18, 24) at the junctions, the third and fourth grid bars (30, 32) being additionally connected with each other at junctions arranged at the flanks lying between the depressions and the protrusions, characterized in - that each first grid bar has at least one interruption zone along its extension between the longitudinal edges or between a longitudinal edge and a transversal edge, and - that the interruption zones of adjacent first grid bars are arranged laterally offset and in particular without overlap. - at least a corrugated grid mat provided with - linearly extending valleys and ridges alternately arranged one beside the other, having flanks connecting the same, - two longitudinal edges substantially parallel to each other, as well as transversal edges extending transversely thereto, - linear first grid bars, substantially parallel to each other, which extend at angles different from 90° with respect to both the longitudinal edges and the transversal edges, and which extend at the bottom along the depressions and at the top along the protrusions, - wave-like second grid bars extending substantially parallel to the longitudinal edges and connected with the first grid bars at junctions arranged along imaginary, substantially linear junction lines, und - wave-like third grid bars, substantially parallel with respect to each other, and wave-like fourth grid-bars, also substantially parallel with respect to each other, said grid bars being connected with the first and second grid bars (18, 24) at the junctions, the third and fourth grid bars (30, 32) being additionally connected with each other at junctions arranged at the flanks lying between the depressions and the protrusions, - linearly extending valleys and ridges alternately arranged one beside the other, having flanks connecting the same, - two longitudinal edges substantially parallel to each other, as well as transversal edges extending transversely thereto, - linear first grid bars, substantially parallel to each other, which extend at angles different from 90° with respect to both the longitudinal edges and the transversal edges, and which extend at the bottom along the depressions and at the top along the protrusions, - wave-like second grid bars extending substantially parallel to the longitudinal edges and connected with the first grid bars at junctions arranged along imaginary, substantially linear junction lines, und - wave-like third grid bars, substantially parallel with respect to each other, and wave-like fourth grid-bars, also substantially parallel with respect to each other, said grid bars being connected with the first and second grid bars (18, 24) at the junctions, the third and fourth grid bars (30, 32) being additionally connected with each other at junctions arranged at the flanks lying between the depressions and the protrusions, - that each first grid bar has at least one interruption zone along its extension between the longitudinal edges or between a longitudinal edge and a transversal edge, and - that the interruption zones of adjacent first grid bars are arranged laterally offset and in particular without overlap.