New scroll profiles based on an algebraic spiral and their application to small-capacity refrigeration compressors

The scroll-wrap profile is an important factor for improving performance and reliability of scroll fluid machines. Circular involutes are generally used in current scroll compressors. In this paper, the authors have adopted an algebraic spiral (r = a{phi}{sup {kappa}}) as the basic curve for their scroll-wrap profiles. The advantages of using this spiral are as follows: (1) The scroll-wrap thickness can be changed according to strength requirements. (2) Scroll-wrap dimensions can be reduced to some extent from those used with an involute curve under the same design conditions. (3) The top clearance volume can be reduced or even eliminated. The authors applied this new profile in a small-capacity refrigeration compressor and its excellent features were confirmed.