29 at the outlet of the mixer 5 above the conveyor belt 29 approximately in the zone below the housing wall 5c there is arranged a roll 34 which presses down on the four layer fiber tuft mass against the conveyor belt 29 the roll 34 is sealed against the lower edge of the wall 5c by an elastic seal 35 made of rubber or similar material the fiber material leaving the mixer 5 is introduced by the driven conveyor belt 29 to the needle machine 7 which has cooperating feed rolls 30a 30b the driven conveyor belt 29 changes direction downstream of the outlet pressure roll 34 and is thus oriented towards the needle machine 7 stated differently the portion 29d of the conveyor belt 29 is situated externally of the outline of the mixer 5 and extends up to the feed rolls 30a 30b of the needle machine 7 which is spaced from the mixer 5 between the mixer 5 and the needle machine 7 above the conveyor belt portion 29d a conveyor belt 33 is arranged for guiding and compressing the four layer fiber material fig4 shows a multimixer 5 39 having feed chutes hoppers 20 39 21 39 22 39 and 23 39 above the feed chutes 20 39 21 39 there is arranged a condenser 25a with a screen drum and above the feed chutes 22 39 23 39 there is arranged a condenser 25b with a screen drum the condenser.