Involute Foil Regenerator

Abstract

A regenerator having a plurality of involute foils disposed in an annular gap between an inner cylindrical tube and an outer cylindrical tube. The involute shape of the foils provides uniform spacing throughout the entire regenerator and substantial surface area for fluid contact.

1 . A method of making a regenerator through which fluid can flow for transferring thermal energy into and out of the fluid, the method comprising:
 a) forming an inner wall having a radially outwardly facing cylindrical surface;   b) disposing an outer wall substantially coaxial with the inner wall and spaced radially outwardly therefrom, forming an annular gap between the inner wall and the outer wall, said outer wall having a radially inwardly facing cylindrical surface;   c) mounting a plurality of foils in the annular gap extending along substantial involutes of the radially outwardly facing cylindrical surface, each foil having an inner edge at the radially outwardly facing cylindrical surface of the inner wall at substantially equal circumferentially spaced intervals and an outer edge spaced from the inner edge, the outer edge being circumferentially displaced from the inner edge and extending toward the radially inwardly facing cylindrical surface of the outer wall;   wherein a plurality of longitudinal gaps, each longitudinal gap being formed between one of the foils and its respective next adjacent foil, extends from the inner wall to substantially the outer wall, the longitudinal gaps forming involute flow passages that extend substantially uninterrupted between the inner and outer walls.   
     
     
         2 . The method in accordance with  claim 1 , further comprising:
 a) disposing a plurality of substantially planar foils substantially parallel to one another, each of said foils having an inner edge and an opposing outer edge;   b) inserting a spacer between each foil;   c) heating the inner edge of the foils and the spacers until they are bonded together, thereby forming a wall at the inner edges of the foils, said wall having first and second opposing edges; and   d) bending the wall and mounting the first wall edge to the second wall edge, thereby forming said inner wall.   
     
     
         3 . The method in accordance with  claim 1 , further comprising:
 a) disposing a plurality of substantially planar foils substantially parallel to one another, each of said foils having an inner edge and an opposing outer edge;   b) forming at least one aperture in each foil, and aligning said apertures;   c) inserting a ring through the aligned apertures in the foils;   d) forming a wall at the inner edges of the foils, said wall having first and second opposing edges;   e) bending the wall and mounting the first wall edge to the second wall edge, thereby forming said inner wall.