Patent ID: 8899956

Claim:
A device for producing pipes made of thermoplastic with annular transverse profilings with a cross section in the form of undulation peaks and undulation troughs, with half-moulds, which complete one another pairwise along a straight mould section to form a closed mould, which is moveable in a motion direction, with a central longitudinal axis, which is transportable in the circuit counter to the movement direction of the mould to an upstream end of the mould section and which have an annular internal profiling, which is loadable with a partial vacuum, with a smallest internal diameter D 39 to produce the transverse profiling, and with an extrusion tool, which has a nozzle support body with one of an external diameter D 33 and D 33 ′ with at least one channel for plastic melt, which has a nozzle with a diameter D 19 , which is connected by means of a channel end portion ( 31 ) widening toward the nozzle to the channel, which has an inner nozzle ring and an outer nozzle ring, which between them limit the channel end portion ( 31 ) and which are fastened to the nozzle support body, wherein one of the external diameter D 33 and D 33 ′ of the nozzle support body is smaller than the diameter D 19 of the nozzle, wherein the nozzle support body—in relation to the movement direction ( 8 )—upstream of the outer nozzle ring ( 30 ), is covered with exchangeably attached hollow half-shells, which form a cylindrical external face with a diameter D 37 and wherein a narrow annular gap with a gap width a is formed between the cylindrical external face and the internal profiling with the smallest internal diameter D 39 .