Patent ID: 6050797
Filing Date: 2000-04-18
Classification: F04C

Abstract:
A screw machine including a rotor housing, an inlet casing secured to said rotor housing, a pair of operatively connected rotors having first and second ends and located in said rotor housing with each rotor having a shaft portion extending into said inlet casing, bearing means supporting said rotors, means for supplying gas at suction pressure to said rotors and means for delivering compressed gas at discharge pressure from said rotors, gas at discharge pressure acting on a first end of each of said rotors and tending to move each of said rotors in a first direction, thrust balancing structure for providing a force on at least one of said rotors tending to move said one rotor in a second direction which is opposite to said first direction, said thrust balancing structure comprising:fluid pressure responsive means located on the respective shaft portion of said one rotor so as to be integral therewith;said fluid pressure responsive means forming a portion of a first sealed chamber having a first surface exposed to said first sealed chamber such that fluid pressure acting on said first surface tends to move said one rotor in said second direction; andmeans for supplying gas at discharge pressure to said first sealed chamber.