Scroll-type compressor with reduced housing radius

In a scroll-type fluid compressor unit comprising a cylindrical compressor housing having a front end plate and a rear end plate, a fixed scroll member fixedly disposed within said compressor housing and having first circular end plate means to which first wrap means is affixed, an orbiting scroll member orbitably disposed within said compressor housing and having second circular end plate means to which second wrap means is affixed, said second wrap means being similar to said first wrap means in number of turns, pitch and thickness, driving means for effecting orbital motion of said orbiting member, and said first and second wrap means interfitting with an angular phase difference of 180.degree. to provide a plurality of line contacts to define at least one pair of sealed fluid pockets which move with a reduction of volume thereof by the orbital motion of said orbiting scroll member, to thereby compress the fluid in the pockets, the improvement comprising:

• said second circular end plate means having substantially a radius of (2a-R)/2, where a is a distance from the center of said second wrap means to its outer terminal end and R is the radius of said orbital motion, and the center of said second end plate means being offset from the center of said second wrap means toward the outer terminal end of said second wrap means by R/2, to thereby reduce the radius of said cylindrical compressor housing.