to prevent penetration of spinning liquid into this gap it exercises in this case in an essentially simpler and reliable manner the same function as did previously the expensive and fault susceptible membrane seal of the prior art side 14 of seal 13 is considered alone of tubular design side 15 has considered alone the shape of a flat seal flat gasket side 14 seals in a radial direction under pressure radial pressure component as shown in fig1 side 14 of seal 13 is disposed partially inside a bottom portion of potlike space 6 and partially inside spinneret holder 1 also as illustrated in fig1 angle seal 13 is preferably l shaped instead of perforated plate 11 as depicted in fig1 spinneret 2 can alternatively be disposed at this point at the inner surface of spinneret holder 1 a corresponding projecting support surface for supporting spinneret 2 is to be provided in an alternate embodiment a mixing element 12 39 shown in phantom in fig1 is disposed in the channel 12 of the thrust piece 4 the mixing element 12 39 is preferably a static mixer fig2 depicts an embodiment of thrust piece 4 the parts 5 7 12 and 20 which have already been described above for fig1 will not be enumerated and described again here reference numeral 21 depicts one of for example three holes which facilitate fixing thrust piece 4 during the.