| 摘要 |
<p>A drive system for an extruder powered by a low speed hydraulic motor (3) comprises a combination of a conventional (quiet) electric motor (5), pref. running at constant speed, driving a variable output pump pref. running immersed in the hydraulic medium. The proportion of the pump power applied to the screw drive (3) can be varied stepwise or, pref. continuously.S System is esp. for extrusion units producing blow moulding parisons to precisely defined variable output rates to control wall thickness profiles etc. System is simpler and quieter than use of variable speed mechanical gearboxes or direct drive variable speed electric motors with adequate torque at various speeds.</p> |
