apparatus it is also possible to form webs on an apparatus of this type in such a case it might possibly be advantageous to subject the material to be formed into the web to a preliminary pressure treatment this is the purpose of the pressure arrangement 40 shown on fig2 it includes two endless forming belts 41 and 44 which extend over the width of the web with the forming belt 41 in direct contact of the upper surface of the material to be formed and with the lower forming belt 44 abuting the lower surface of the pressure belt 5 which as noted above is led in a path which will take it through this apparatus support constructions 45 and 46 which are connected to one another beyond the edges of the web are provided and pressure treating arrangements 42 and 43 are positioned between the support constructions 46 and 45 and forming belts 44 and 41 respectively as noted above the belts 5 and chains 9 are passed over guide rollers 30 31 and 32 positioned around the drum 2 one or more of these guide rollers may be constructed as idler rolls in order to provide the necessary tension on pressure belts 5 and 5 39 and the roller chains 9 in order to obtain trouble free running tension of this nature contributes somewhat to the pressure of the surface of the drum 2 but is minor in comparison.