the plate 6 each through hole 8 is positioned so close to the edge of the boundary 7 that between the through hole 8 and the boundary 7 only a dome 10 is arranged which is also designated as passage thus this passage 10 completely fills the space between the boundary 7 and the through hole 8 the through hole 8 has a semicircular shape wherein the radius of the semicircle is completely surrounded by the passage 10 fig3 b shows a closer view of a through hole 8 a with the passage 10 surrounding said hole the passage 10 has a plurality of elongated holes 13 which fill the entire surface of the passage 10 and which face away from the base plate 12 of the elongated plate 6 said passage is raised above the plane predetermined by the base plate 12 so that the elongated holes 13 are positioned in a plane above the plane spanned by the base plate 12 the medium to be cooled is fed through the through hole 8 a to the heat exchanger and is discharged again from the heat exchanger through the additional through hole 8 b which is illustrated in fig3 a the elongated holes 13 serve for feeding the cooling medium in this case air to the heat exchanger.