Fin and tube heat exchanger

1. A heat exchanger, comprising:

a plurality of rows of tubes intersecting a plurality of substantially planar fins, each of the fins comprising:

a first side;

a second side opposite the first side;

an upstream bank of louvers configured to direct fluid only from the first side of the fin to the second side of the fin as the fluid passes along the fin past at least a first row of the plurality of rows of tubes;

a first plurality of stiffening breaks disposed in the upstream bank of louvers, wherein the first plurality of stiffening breaks comprises a first plurality of converging stiffening breaks followed by a first plurality of diverging stiffening breaks, where the first plurality of stiffening breaks defines a first plurality of X-shaped stiffening breaks spaced between adjacent tubes in the at least a first row of the plurality of rows of tubes;

a downstream bank of louvers adjacent the upstream bank of louvers, wherein the downstream bank of louvers is configured to direct fluid only from the second side of the fin to the first side of the fin as the fluid passes along the fin past at least a second row of the plurality of rows of tubes, wherein all of the downstream bank of louvers are angled in a second sloping direction and protrude from both the first and second sides, wherein the first and second sloping directions are opposite from one another; and

a second plurality of stiffening breaks disposed in the downstream bank of louvers, wherein the second plurality of stiffening breaks comprises a second plurality of converging stiffening breaks followed by a second plurality of diverging stiffening breaks;

wherein the upstream bank of louvers and/or the downstream bank of louvers further includes a region defined between the first and second plurality of stiffening breaks having at least one louver extending uninterrupted between an adjacent pair of tube holes, and wherein the at least one louver extends above and below the planar surface of the fin;

wherein the first plurality of converging stiffening breaks align with the first plurality of diverging stiffening breaks directly along first and second angled lines to define the first plurality of X-shaped stiffening breaks.

2. The heat exchanger of claim 1 , wherein all the louvers in the upstream bank define a first slope in a first sloping direction with respect to the fin and all the louvers in the downstream bank define a second slope in the second sloping direction, wherein the second slope is the negative of the first slope.

3. The heat exchanger of claim 1 , wherein all the louvers in at least one of the upstream or the downstream bank extend an equal distance from the first side or the second side of the fin.

4. The heat exchanger of claim 1 , wherein the louvers are formed integrally with the fin to form a one-piece structure.

5. The heat exchanger of claim 1 , wherein at least one end of the substantially planar fin is bent out of the plane of the fin to provide strength to the end, wherein the end is corrugated.

6. The heat exchanger of claim 1 , comprising spacers configured to space adjacent fins at a predetermined distance from each other, wherein the spacers are disposed between adjacent banks.

7. The heat exchanger of claim 1 , wherein the first plurality of louvers extends adjacent to the first row of the plurality of rows of tubes to define first curved perimeters tracking first contours of the first row of the plurality of rows of tubes, the second plurality of louvers extends adjacent to the second row of the plurality of rows of tubes to define second curved perimeters tracking second contours of the second row of the plurality of rows of tubes.

8. A heat exchanger, comprising:

a first row of cylindrical tubes;

a second row of cylindrical tubes;

a plurality of substantially planar fins arranged generally parallel to one another, wherein the plurality of substantially planar fins are separate from one another, wherein each fin of the plurality of substantially planar fins comprises:

a first row of cylindrical openings supporting the first row of cylindrical tubes;

a second row of cylindrical openings supporting the second row of cylindrical tubes;

a first plurality of louvers disposed along the first row of cylindrical openings supporting the first row of cylindrical tubes, wherein all of the first plurality of louvers are angled in a first sloping direction from the first row of cylindrical tubes toward the second row of cylindrical tubes, all of the first plurality of louvers protrude from a first common side of the fin, and the first plurality of louvers extends adjacent to the first plurality of cylindrical openings to define first curved perimeters tracking first contours of the first plurality of cylindrical openings;

a first plurality of stiffening breaks disposed in the first plurality of louvers, wherein the first plurality of stiffening breaks comprises a first plurality of converging stiffening breaks followed by a first plurality of diverging stiffening breaks;

a second plurality of louvers disposed along the second row of cylindrical openings supporting the second row of cylindrical tubes, wherein all of the second plurality of louvers are angled in a second sloping direction with a generally opposite slope relative to first plurality of louvers, all of the second plurality of louvers protrude from a second common side of the fin, and the second plurality of louvers extends adjacent to the second plurality of cylindrical openings to define second curved perimeters tracking second contours of the second plurality of cylindrical openings;

a second plurality of stiffening breaks disposed in the second plurality of louvers, wherein the second plurality of stiffening breaks comprises a second plurality of converging stiffening breaks followed by a second plurality of diverging stiffening breaks;

wherein the first plurality of louvers and/or the second plurality of louvers further includes a leading louver and a trailing louver, each of the leading and trailing louvers having a shorter width than an intermediate louver positioned between the converging stiffening breaks and the diverging stiffening breaks;

wherein the first plurality of stiffening breaks defines a first plurality of X-shaped stiffening breaks, and the second plurality of stiffening breaks defines a second plurality of X-shaped stiffening breaks; and

wherein the first plurality of stiffening breaks and the second plurality of stiffening breaks are staggered relative to one another, wherein a first set of stiffening breaks in the first and second plurality of X-shaped stiffening breaks are directly aligned with one another along a first angled line, wherein a second set of stiffening breaks in the first and second plurality of X-shaped stiffening breaks are directly aligned with one another along a second angled line.

9. The heat exchanger of claim 8 , wherein the first and second common sides are different from one another.

10. The heat exchanger of claim 8 , wherein all of the first plurality of louvers protrude from both the first common side and the second common side of the fin, all of the second plurality of louvers protrude from both the first common side and the second common side of the fin.

11. The heat exchanger of claim 8 , wherein each of the first plurality of cylindrical openings comprises a first cylindrical flange protruding from the fin, and each of the second plurality of cylindrical openings comprises a second cylindrical flange protruding from the fin.

12. A heat exchanger, comprising:

a first row of cylindrical tubes;

a plurality of substantially planar fins arranged generally parallel to one another, wherein the plurality of substantially planar fins are separate from one another, wherein each fin of the plurality of substantially planar fins comprises: a first row of cylindrical openings supporting the first row of cylindrical tubes;

a first plurality of louvers disposed along the first row of cylindrical openings supporting the first row of cylindrical tubes, wherein all of the first plurality of louvers are angled in a first sloping direction and protrude from a first common side of the fin, and the first plurality of louvers extends adjacent to the first plurality of cylindrical openings to define first curved perimeters tracking first contours of the first plurality of cylindrical openings;

a first plurality of stiffening breaks disposed in the first plurality of louvers, wherein the first plurality of stiffening breaks comprises a first plurality of converging stiffening breaks followed by a first plurality of diverging stiffening breaks,

wherein the first plurality of stiffening breaks defines a first plurality of X-shaped stiffening breaks spaced between pairs of adjacent first curved perimeters in the first plurality of louvers; and

wherein the first plurality of louvers include at least one louver extending uninterrupted between one tube opening and an adjacent tube opening as well as between the first plurality of converging stiffening breaks and the first plurality of diverging stiffening breaks, and wherein the at least one louver extends above and below the planar surface of each of the fins;

wherein the first plurality of converging stiffening breaks align with the first plurality of diverging stiffening breaks directly along first and second angled lines to define the first plurality of X-shaped stiffening breaks.

13. The heat exchanger of claim 12 , comprising:

a second row of cylindrical tubes;

a second row of cylindrical openings supporting the second row of cylindrical tubes;

a second plurality of louvers disposed along the second row of cylindrical openings supporting the second row of cylindrical tubes, wherein all of the second plurality of louvers are angled in a second sloping direction and protrude from a second common side of the fin, the second plurality of louvers extends adjacent to the second plurality of cylindrical openings to define second curved perimeters tracking second contours of the second plurality of cylindrical openings, and the first and second sloping directions are opposite from one another; and

a second plurality of stiffening breaks disposed in the second plurality of louvers, wherein the second plurality of stiffening breaks comprises a second plurality of converging stiffening breaks followed by a second plurality of diverging stiffening breaks.

14. A heat exchanger, comprising:

a first row of cylindrical tubes;

a plurality of substantially planar fins arranged generally parallel to one another, wherein the plurality of substantially planar fins are separate from one another, wherein each fin of the plurality of substantially planar fins comprises:

a first row of cylindrical openings supporting the first row of cylindrical tubes;

a first plurality of louvers disposed along the first row of cylindrical openings supporting the first row of cylindrical tubes, wherein all of the first plurality of louvers are angled in a first sloping direction and protrude from a first common side of the fin, and the first plurality of louvers extends adjacent to the first plurality of cylindrical openings to define first curved perimeters tracking first contours of the first plurality of cylindrical openings; and

a first plurality of stiffening breaks disposed in the first plurality of louvers, wherein the first plurality of stiffening breaks comprises a first plurality of converging stiffening breaks that extend through all of a first sequence of louvers in the first plurality of louvers on the first common side of the fin, wherein the first plurality of stiffening breaks comprises a first plurality of diverging stiffening breaks that extend through all of a second sequence of louvers in the first plurality of louvers on the first common side of the fin, wherein the first plurality of converging stiffening breaks align with the first plurality of diverging stiffening breaks directly along first and second angled lines to define a first plurality of X-shaped stiffening breaks spaced directly between pairs of adjacent first curved perimeters in the first plurality of louvers.

15. The heat exchanger of claim 14 , wherein each fin of the plurality of substantially planar fins comprises:

a second row of cylindrical openings supporting a second row of cylindrical tubes;

a second plurality of louvers disposed along the second row of cylindrical openings supporting the second row of cylindrical tubes, wherein all of the second plurality of louvers are angled in a second sloping direction and protrude from a second common side of the fin, the second plurality of louvers extends adjacent to the second plurality of cylindrical openings to define second curved perimeters tracking second contours of the second plurality of cylindrical openings, wherein the first and second sloping directions are opposite from one another; and

a second plurality of stiffening breaks disposed in the second plurality of louvers, wherein the second plurality of stiffening breaks comprises a second plurality of converging stiffening breaks that extend through all of a third sequence of louvers in the second plurality of louvers, wherein the second plurality of stiffening breaks comprises a second plurality of diverging stiffening breaks that extend through all of a fourth sequence of louvers in the second plurality of louvers, wherein the second plurality of converging stiffening breaks align with the second plurality of diverging stiffening breaks directly along third and fourth angled lines to define a second plurality of X-shaped stiffening breaks spaced directly between pairs of adjacent second curved perimeters in the second plurality of louvers.

16. The heat exchanger of claim 15 , wherein all of the first plurality of louvers protrude from both the first common side and the second common side of the fin, and wherein all of the second plurality of louvers protrude from both the first common side and the second common side of the fin.