the principal drawing field hf since contamination and foreign particulate is eliminated by the cooling medium k feeding into the suction collection line 30 fig4 shows a further embodiment of a housing 15 the openings 16 17 for the inlet and outlet of the cooling medium k are so ordered in this case that the housing 15 experiences a through flow from upstream i e the same as the drawing direction in order that an especially uniform through flow and cooling of the draft system 4 can be reached the housing 15 is provided with two openings namely 16 17 for the inlet and the outlet of the cooling medium k the cooling medium k passes through a least one temperature controller 20 by means of the openings 16 into the said housing 15 by means of this design two parallel flows are formed so that the upper rolls 5 a 6 a 7 a and the under rolls 5 b 6 b 7 b are evenly cooled the air flow that is the flow of cooling means reliably removes the accumulated heat in the draw fields vf hf moreover fibers and contamination from the draw fields vf hf are removed by the flow of cooling medium so that no additional suction or blower apparatuses need be used the flowing cooling medium k as well as the.