Patent ID: 6139299
Filing Date: 2000-10-31
Classification: F01C

Abstract:
A conjugate pair of intermeshing rotors having helical lobes comprising helical crests and intervening grooves and adapted for rotation about parallel axes within a working space of a screw rotor machine, each rotor has a tip circle, a pitch circle, and a root circle, one rotor of each pair being a female rotor such that the major portion of each lobe of said female rotor is located inside said pitch circle of said female rotor, the other rotor being a male rotor is located outside said pitch circle of said male rotor, the lobes of one rotor following the grooves of the other rotor to form a continuous sealing line between said pair of rotors, a first portion of each female lobe located generally between the tip circle and pitch circle of said female rotor containing a first segment having a large radius portion (F.sub.5 ""-F.sub.6) nearer said tip circle and said female rotor and a smaller radius portion (F.sub.6 -F.sub.7) nearer said pitch circle of said female rotor, wherein said large radius potion of said segment intersects the tip circle of said female rotor at an angle other than 0.degree..