Liquid injection type screw compressor with lubricant relief chamber

A liquid injection screw compressor comprising:

• a casing;
• a first end of said casing being an intake end;
• a second end of said casing being a discharge end;
• a male rotor and a female rotor in said casing;
• said male rotor and said female rotor being rotatable in engagement with each other;
• a discharge end on said male rotor;
• a discharge end on said female rotor;
• said male rotor having a number Z of helical teeth having convex profiles;
• said male rotor having an outer radius of R;
• said teeth of said male rotor each having a chamfered portion along a leading edge on said discharge end of the male rotor facing said discharge end of said casing;
• said chamfered portion beginning at a point P located in said leading edge at angle .phi..sub.S from a tip of each of said teeth;
• said angle .phi..sub.S being in a first range defined by a first expression
• -1.degree..ltoreq..phi..sub. S .ltoreq.35.degree.
• and having a rotation axis of said male rotor as a center and in a positive direction of rotation of said male rotor;
• said chamfered portion extending to and ending at a point Q located on said leading edge at an angle .phi..sub.E ;
• said angle .phi..sub.E being in a second range defined by a second expression
• .phi..sub.S .phi..sub.E .ltoreq.160.degree./Z;
• said chamfered portion extending a distance D.sub.r in a radial direction of said male rotor and a distance D.sub.S in an axial direction of said male rotor;
• and
• said distances D.sub.r and D.sub.S being respectively defined by ranges of the following expressions:
• 0.007R.ltoreq.D.sub.r .ltoreq.(1.2/Z)R;
• and
• 0.007R.ltoreq.D.sub.S .ltoreq.(1.2/Z)R

A liquid injection screw compressor comprising:

• a casing having an intake port and a discharge port;
• rotor means in said casing for taking in a gas through said intake port, transporting said gas through spaces, and discharging said gas through said discharge port;
• means defining a three-sided passage between a first space compressing said gas and a second space receiving said compressed gas;
• said three-sided passage including means for relieving pressure exerted upon said liquid by said rotor means while maintaining efficiency of said screw compressor;
• said means defining said three-sided passage further comprising:
• said rotor means including a first rotor having a leading edge at a discharge end thereof;
• a second rotor rotating in engagement with said first rotor;
• and
• said leading edge having a chamfer thereon so as to produce a three sided passage having a chamfer surface, an inside surface of said casing, and said second rotor as sides of the three sided passage;
• said chamfer beginning at a point P located in said leading edge at an angle .phi..sub.S from a tip of said rotor;
• said angle .phi..sub.S being in a first range defined by a first expression
• -1.degree..ltoreq..phi..sub. S .ltoreq.35.degree.
• and having a rotation axis of said rotor as a center and with a rotation direction of the rotor being in a positive direction;
• said chamfer extending to and ending at point Q located on said leading edge at a an angle .phi..sub.E ;
• said angle .phi..sub.E being in a second range defined by a second expression
• .phi..sub.S <.phi..sub.E .ltoreq.160.degree./Z;
• said chamfer extending a distance D.sub.r in a radial direction of said rotor and a distance D.sub.S in an axial direction of said rotor;
• and
• said distances D.sub.r and D.sub.S being respectively defined by ranges of the following expressions:
• 0. 007R.ltoreq.D.sub.r .ltoreq.(1.2/Z)R;
• and
• 0.007R.ltoreq.D.sub.S .ltoreq.(1.2/Z)R.