Summary of the extruder
To realize this object, is it proposed according to theextruder, that the axis of the conveying gear be arranged essentially at right angles to the axis of theextruder machine and that the axis of the positive-displacement gear be arranged essentially in the same direction as the axis of the extruder screw.
This gives rise to the process engineering advantage that the filling pressure is substantially lower than is the case with the known epicyclic gear pumps, especially since the flow ducts assigned to each planet wheel thereof are dispensed with, the advantage of this being that the twin screw extruder  requires a lower pressure build-up and therefore the viscous masses are heated to a lesser extent.
According to a further feature of the invention, the housing of the gear pump is integrated into the housing of the single screw extruder , with the result that the feed orifices are likewise dispensed with, so that even less heat and therefore even less dissipated energy occur.
According to a further feature of the pelletizing machine , a uniform volume flow can be achieved in that the conveying gear and the positive-displacement gear are designed as bevel gears meshing with one another.
A screw extruder conveys by virtue of internal friction and generates a drag flow along the extruder screw. If, in addition to conveyance, a pressure gradient has to be built up, a pressure volume flow acting in the opposite direction is superposed on the drag volume flow. This leads to increased dissipative heating and to a lowering of the actually conveyable mass flow. By contrast, a positive-displacement gear pump is a volumetric conveyor, and therefore, here, the conveying rate depends on the counterpressure to a substantially lesser extent. The solution according to the invention therefore makes it possible to convey relatively independently of pressure, while a low mass temperature can be achieved by virtue of the positive-displacement gear pump designed according to the invention.