Finned cylindrical heat exchanger

A heat exchanger, comprising:

• (a) a cylindrical middle wall open at both ends extending along an axis between a first end and a second end, the middle wall having an outer surface and being free of perforations, the middle wall having a predetermined thickness;
• (b) an inner wall located inwardly of the middle wall and being attached to the inner surface of the middle wall thereby providing one or more axially-extending spaces therebetween, wherein the inner wall is curved so as to follow the curvature of the middle wall, the inner wall defining an open interior space having opposed open ends, the open interior space adapted for receiving additional components of a heat exchanger system;
• (c) a first fluid flow passage for the flow of a first fluid through the heat exchanger, the first fluid flow passage comprising the one or more axially-extending spaces formed between the inner wall and the middle wall, wherein the first fluid flow passage is open at its axially-spaced ends, the open axially-spaced ends of the first fluid flow passage being free of corresponding inlet and outlet manifolds thereby allowing the first fluid to flow axially through the first fluid flow passage;
• (d) an outer wall located outwardly of the middle wall and being curved so as to follow the curvature of the middle wall, wherein one or more axially-extending spaces are provided between the middle wall and the outer wall, the outer wall sealing against the outer surface of the middle wall proximate to a first and a second end of the outer wall;
• (e) a second fluid flow passage comprising the one or more axially-extending spaces formed between the middle wall and the outer wall, wherein the second fluid flow passage is open at its axially spaced ends, and said second fluid flow passage having a first annular open space at one of the axially spaced ends of the second fluid flow passage and a second annular open space at the other one of said axially spaced ends of the second fluid flow passage;
• (f) a first manifold in flow communication with the first annular open end of the second fluid flow passage, the first manifold extending circumferentially around the outer surface of the first end of the middle wall, wherein the first manifold is provided with a first fluid opening;
• (g) a second manifold in flow communication with the second annular open end of the second fluid flow passage, the second manifold extending circumferentially around the outer surface of the second end of the middle wall, wherein the second manifold is provided with a second fluid opening;
• wherein the predetermined thickness of the middle wall is substantially greater than the thickness of the inner wall and of the outer wall, respectively, and wherein one of the first and second fluid openings serves as an inlet opening;
• and
• wherein a circumferentially-extending flow restricting rib is formed on and projects radially outwardly from the outer surface of the middle wall, the circumferentially-extending rib having a length that extends around the circumference of the outer surface of the middle wall, the length of the circumferentially-extending rib being greater than the width of the circumferentially-extending rib, wherein the width is the dimension in the radial direction of the heat exchanger, the circumferentially-extending rib being located proximate to and partially obstructing the annular open end of the second fluid flow passage that is closest to the inlet opening to fluid flowing in the axial direction, wherein the outward radial projection of the circumferentially-extending flow restricting rib varies along the circumference of the outer surface of the middle wall.