Scroll compressor having bypass valves

A scroll compressor comprising:

• a closed vessel having a discharge chamber defined therein;
• a stationary scroll accommodated in said closed vessel and having a stationary end plate and a stationary scroll wrap protruding axially from said stationary end plate, said stationary scroll also having a discharge port defined therein at a central portion thereof and a suction chamber formed outside said stationary scroll wrap;
• an orbiting scroll accommodated in said closed vessel and having an orbiting end plate and an orbiting scroll wrap protruding axially from said orbiting end plate so as to engage with said stationary scroll wrap to define a plurality of compression chambers therebetween;
• an electric motor for driving said drive shaft;
• a frame rotatably supporting said drive shaft, said stationary scroll being secured to said frame;
• a rotation prevention member for preventing rotation of said orbiting scroll about its own axis;
• a check valve for selectively opening and closing said discharge port and allowing a fluid to flow only from said discharge port towards said discharge chamber;
• said stationary end plate having at least two first bypass holes defined therein at locations symmetrical in terms of pressure, said two first bypass holes being open to ones of said compression chambers closest to said discharge port, and said two first bypass holes being in communication with said discharge chamber;
• a bypass valve for selectively opening and closing said first bypass holes and allowing the fluid to flow only from said compression chambers towards said discharge chamber through said first bypass holes;
• and
• said first bypass holes being positioned so that no portion of any of said first bypass holes is closed by said orbiting scroll wrap immediately after said compression chambers closest to said discharge port have communicated with said discharge port.