Process and apparatus for the fabrication of a flat-shaped hollow body

Process for the continuous manufacture of a flat-shaped body, particularly a ventilation and drainage panel or mat or a heat exchange panel or mat, equipped with fluid transport ducts, which have fluid entry ports and fluid exit ports, through the use of a mold consisting of continuously-moving mold segment halves, moving along a forming line which, upon entering the forming die, are moved through the forming die in close contact with each other in the operating direction and with the forming die closed on pairs of mold segment halves, wherein a warm thermoplastic hose is introduced into the forming die and formed there under vacuum, wherein said hose has a relatively large wall thickness, and wherein the hose stock, in at least a portion of its cross section, is subjected to vacuum action before the two mold segment halves are brought together and is then pressed together thereby forming voids and welds over at least a portion of its cross section.