| 摘要 |
The planetary roller extruder, for the extrusion of thermoplastics, has a full wall thickness (1) for the bush of <= 10 mm with a pitch circle diameter of 250 mm at the bush teeth, and <= 11 mm with larger pitch circle diameters. The full wall thickness (1) is preferably 3-8 mm. The full wall thickness (1), according to the pitch circle diameter is set as: pitch circle diameter: 70mm, 100mm, 150mm, 180mm, 200mm, 250mm and 300mm and corresponding full wall thickness: 3.0-6.5mm, 3.5-7.0mm, 4.4-7.9mm, 4.9-8.4mm, 5.4-8.8mm, 6.2-9.7mm and 7.1-10.6mm respectively. The full wall thickness (1) represents the gap between the deepest tooth and the deepest groove, measured on the projection of the bush edges out of the longitudinal line. The bushes are spark eroded, for high accuracy. The teeth are spark eroded, so that they can be worked after hardening. The planetary roller extruder has a heating/cooling circuit, with controlled pressure valves and a pressure pump and/or reservoir. The pump and/or reservoir is switched off on achieving minimum pressure difference between the pressure of the molten material in the extruder and the pressure in the heating/cooling circuit. The pressure difference is 10 bar. The pressure is reduced in the heating/cooling circuit by a pressure limit valve, when the pressure difference threatens to go into a negative value. The extruder has a pressure of 1 bar. |
