Variable-capacity scroll-type compressor

Claim 1

A scroll-type compressor comprising: a stationary scroll including a disk-shaped, stationary end plate having surfaces and a discharge port formed at a center of said stationary end plate, and a stationary spiral wrap extending perpendicularly from one surface of said stationary end plate and curving outwardly from the center of said stationary end plate in the shape of a spiral; an orbiting scroll including a disk-shaped moving end plate having surfaces and a central rotating axis, and a moving spiral wrap extending perpendicularly from one surface of said moving end plate and curving outwardly from the central rotating axis of said moving end plate in the shape of a spiral, said stationary scroll and said orbiting scroll being engaged with one another with said stationary and moving end plates parallel and said spiral wraps interfitting with one another so as to define a plurality of compression chambers; means for orbiting said orbiting scroll about the center of said stationary end plate while preventing said orbiting scroll from rotating about the central rotating axis; a valve chamber formed in said stationary end plate and having a valve seat; a first longitudinally extending by-pass passage formed in said stationary end plate and providing a longitudinal path for communicating between said valve chamber and said compression chambers; a second radially extending by-pass passage formed in said stationary end plate and providing a radial path for communicating between said valve chamber and an exterior of said stationary end plate; and a plate-shaped valve disposed entirely inside said valve chamber to move between a seated portion on said valve seat to close the communicating paths provided by said first and second by-pass passages and an unseated position on said valve seat to open the communicating paths to allow fluid to pass from said first by-pass passage to said second by-pass passage.