Scroll-type refrigerant compressor

A scroll-type refrigerant compressor comprising:

• a housing provided with a suction port for introducing a refrigerant to be compressed into said housing and a delivery port for delivering the refrigerant after compression;
• a suction chamber defined in said housing and fluidly communicated with said suction port;
• a discharge chamber defined in said housing and fluidly communicated with said delivery port;
• a stationary scroll fixed to said housing and provided with an end plate and a spiral member formed on said end plate;
• a movable scroll arranged so as to be eccentrically engaged with said stationary scroll and provided with an end plate and a spiral member formed on said end plate;
• a drive shaft rotatably supported by said housing and providing said movable scroll with an orbital motion relative to said stationary scroll;
• a rotation preventing means arranged for preventing said movable scroll from rotating during the orbital motion thereof;
• a plurality of compressing chambers defined between said stationary and movable scrolls so as to move toward a center of said spiral members in response to the orbital motion of said movable scroll to thereby compress refrigerant sucked into said chambers;
• a plurality of bypass ports and a discharge port formed in said end plate of said stationary scroll, said plurality of bypass ports and said discharge port being disposed so as to permit said plurality of compressing chambers to be fluidly communicated with said discharge chamber, all of said plurality of compressing chambers being constantly communicated with said plurality of bypass ports or said discharge port;
• check valve means arranged in said discharge chamber at positions adjacent to said plurality of bypass ports and said discharge port so as to prevent the refrigerant after compression from returning from said discharge chamber toward said plurality of compressing chambers;
• a fluid channel arranged so as to be extended between said suction chamber and said discharge chamber, for providing a fluid communication therebetween;
• and
• a fluid passage control means arranged in said fluid channel and defining open and closed positions of said fluid channel to thereby regulate the passage of the refrigerant through said fluid channel,
• each of said plurality of bypass ports and said discharge port defining a respective predetermined open area and said plurality of bypass ports and said discharge port being constructed and arranged so that as each respective compressing chamber moves toward said center of said spiral members to compress the refrigerant a sum of said respective predetermined open areas of communicating ports of said plurality of bypass ports and said discharge port which are in communication with said respective compressing chamber increases.