the second wire sieve 5 is positioned downstream of the first guide roll 3 of the first wire sieve 1 so that that an open space is formed on the first wire sieve 1 on the distance between the first guide roll 3 of the first wire sieve 1 and the first guide roll 7 of the second wire sieve 5 the operation zone of the formed between the first and second guide rolls 3 4 of the second wire sieve 1 a nozzle 9 is positioned at the beginning of the operation zone of the apparatus over the open space of the first wire sieve 1 for feeding a pulp fibre suspension 13 on the first wire sieve 1 on the opposite end of the operation zone is winder roll 11 or corresponding winding apparatus for collecting the manufactured yarn the second guide roll 8 of the second wire sieve 5 and the second guide roll 4 of the first wire sieve 1 are spaced apart so that open space is formed on the first wire sieve 1 between these guide rolls 4 8 over this space optional heaters 12 can be placed suitable heaters are infrared heaters hot air dryers or other.