Rabin & Champagne, P.C.
Double screw rotor assembly with electrically controlled clearance adjustment means
 A double screw rotor assembly includes two screw rotors meshed in a bushing inside a casing. The threads of the screw rotors have a constant pitch, and define with the bushing a plurality of air chambers in the pitch. The volumes of the air chambers reduce gradually from the inlet toward the outlet due to reduced tooth height so that the outer diameter defined by the tooth tip of the thread of each screw rotor has the shape of an invertedly disposed cone. An electric driving device is controlled to move the bushing axially in the casing relative to the screw rotors in adjusting the clearance between the inside wall of the bushing and the tooth tip of the thread of each screw rotor, so as to minimize the consumption of starting power and facilitate stable running of the screw rotors, Further, a O-ring is provided at the top wall of the busing and pressed on the casing to keep an airtight status, so as to improve the working efficiency. 
Industrial Technology Research Institute
F F F F
F04C F04C F04C F01C
inventional inventional inventional inventional
Hong-Sheng Ming-Hsin Jiun-Hung
Fang Liu Chen