Heat exchanger

Abstract

A heat exchanger having tubes and fins arranged to have air directed across the fins in a direction transverse to a length of the fins. A first row of tubes are aligned along the length of the fins and include a first distance between centers of adjacent tubes of the first row. A second row of tubes are aligned along the length of the fins and include a second distance between centers of adjacent tubes of the second row. The first and second rows of tubes have a third distance between centers of adjacent tubes of the first and second rows. The third distance is larger than the first and second distances. The heat exchanger further includes a widthwise spacing between the adjacent tubes of the first and second rows that is larger than lengthwise spacings between the adjacent tubes of the first row and the second row.

What is claimed is: 
     
         1 . A heat exchanger comprising:
 fins each having openings;   tubes extending in the openings of the fins for receiving a process fluid;   the fins extending from the tubes for transferring heat between the process fluid and air contacting the fins;   the fins each having a length, a width perpendicular to the length, and a thickness perpendicular to the length and the width, wherein the length of the fin is larger than the width of the fin and the width of the fin is larger than the thickness of the fin;   the tubes and fins arranged to have air directed across the fins in a direction transverse to the length of the fins;   a first row of the tubes aligned along the length of the fins and having a first distance between centers of adjacent tubes of the first row, the first distance extending along the length of the fins;   a second row of the tubes adjacent the first row and aligned along the length of the fins, the second row of the tubes having a second distance between centers of adjacent tubes of the second row, the second distance extending along the length of the fins;   the first row and the second row of tubes having a third distance between centers of adjacent tubes of the first and second rows, the third distance extending along the width of the fins and being larger than the first distance and larger than the second distance; and   a widthwise spacing between the adjacent tubes of the first and second rows that is larger than a first lengthwise spacing between the adjacent tubes of the first row and is larger than a second lengthwise spacing between the adjacent tubes of the second row to reduce airflow pressure drop and increase airflow velocity through the heat exchanger.   
     
     
         2 . The heat exchanger of  claim 1  wherein a ratio of the third distance to at least one of the first distance and the second distance is in a range of approximately 1.04 to approximately 1.5. 
     
     
         3 . The heat exchanger of  claim 1  wherein the tubes have an outer diameter of 0.5 inches;
 wherein the third distance is in a range of approximately 1.3 inches to approximately 1.9 inches; and 
 the first and second distances are each in a range of approximately 1.0 to approximately 1.5 inches. 
 
     
     
         4 . The heat exchanger of  claim 1  wherein the fins each include a first edge and a second edge on opposite sides of the tubes and extending along the length of the fin; and
 wherein the first row of tubes is adjacent one of the first and second edges of the fins, the tubes of the first row of tubes have centers spaced along the width of the fins from the one of the first and second edges by an edge distance that is less than the third distance. 
 
     
     
         5 . The heat exchanger of  claim 4  wherein the tubes have a tube diameter; and
 wherein the edge distance plus half of the tube diameter is approximately half of the third distance. 
 
     
     
         6 . The heat exchanger of  claim 1  wherein the tubes include a third row of tubes adjacent to the first row, the first row of tubes intermediate the third and second rows of tubes along the width of the fins; and
 wherein the tubes of the third row of tubes have centers that are spaced along the width of the fins from centers of adjacent tubes of the first row by a fourth distance that is less than the third distance. 
 
     
     
         7 . The heat exchanger of  claim 6  wherein the tubes of the third row of tubes are offset along the length of the fins from the tubes of the first row. 
     
     
         8 . The heat exchanger of  claim 7  wherein the tubes of the second row are aligned with the tubes of the first row along the width of the fins. 
     
     
         9 . The heat exchanger of  claim 6  wherein the fins each include a first edge and a second edge on opposite sides of the tubes and extending along the length of the fin;
 wherein the tubes have a tube diameter; and 
 wherein the third row of tubes is adjacent one of the first and second edges of the fins, the tubes of the third row of tubes have centers spaced along the width of the fins from the one of the first and second edges by an edge distance; and 
 wherein the edge distance plus half of the tube diameter is approximately half of the fourth distance. 
 
     
     
         10 . The heat exchanger of  claim 1  wherein the tubes of the first row are aligned with the tubes of the second row along the width of the fins. 
     
     
         11 . The heat exchanger of  claim 1  wherein the fins include a row of openings aligned along the length of the fins and intermediate the first and second rows of tubes along the width of the fins. 
     
     
         12 . The heat exchanger of  claim 1  wherein the rows of tubes include six rows of tubes. 
     
     
         13 . The heat exchanger of  claim 1  wherein the tubes and fins are configured to have air directed across the fins in a direction perpendicular to the length. 
     
     
         14 . The heat exchanger of  claim 1  wherein the fins comprise elongated, rectangular plates. 
     
     
         15 . The heat exchanger of  claim 1  wherein the fins have collars fixed to the tubes. 
     
     
         16 . The heat exchanger of  claim 1  wherein the fins each have a wavy surface pattern. 
     
     
         17 . The heat exchanger of  claim 1  wherein the length of each of the fins is at least three times the width of the fin. 
     
     
         18 . The heat exchanger of  claim 1  wherein the first and second rows of tubes each include at least twelve tubes. 
     
     
         19 . The heat exchanger of  claim 1  wherein the tubes are elliptical.