Heat exchange tube and evaporator

Abstract

An evaporator includes a plurality of flat heat exchange tubes extending in a vertical direction and arranged at intervals along a left-right direction with a width direction thereof coinciding with a front-rear direction. The heat exchange tube has a plurality of refrigerant channels arranged along the width direction. The evaporator satisfies a relation 0.558≦A≦1.235, where A is a value in pieces/mm obtained by dividing the number N of the refrigerant channels of the heat exchange tube by a width W of the heat exchange tube as measured in the front-rear direction. Also, the evaporator satisfies a relation 0.35≦Dh≦1.0, where Dh is an equivalent diameter in mm of the heat exchange tube. This evaporator can reduce the temperature difference between air discharged into a compartment when a compressor is turned ON and that when the compressor is turned OFF.

1 . A heat exchange tube assuming a flat form and having a plurality of channels arranged along a width direction of the heat exchange tube,
 the heat exchange tube satisfying a relation 0.558≦A≦1.235, where A is a value in pieces/mm obtained by dividing the number N of the channels by a tube width W and is expressed by A=N/W.   
   
   
       2 . A heat exchange tube assuming a flat form and having a plurality of channels arranged along a width direction of the heat exchange tube,
 the heat exchange tube satisfying a relation 0.35≦Dh≦1.0, where Dh is an equivalent diameter in mm.   
   
   
       3 . A heat exchange tube according to  claim 1  or  2 , wherein each of all the channels excluding two channels located at widthwise opposite ends has an elongated protrusion formed on an inner peripheral surface of the channel and extending in a longitudinal direction of the channel. 
   
   
       4 . A heat exchange tube according to  claim 1  or  2 , wherein each of all the channels excluding two channels located at widthwise opposite ends has a rectangular cross section, and a corner portion of the rectangular cross section has a radius R of 0.1 mm or less. 
   
   
       5 . A heat exchange tube according to  claim 1  or  2 , comprising two flat walls in parallel with each other; first and second side walls extending between and over corresponding side ends of the two flat walls; and partition walls provided between the first and second side walls and extending between the two flat walls and in a longitudinal direction of the two flat walls for separating the adjacent channels from each other;
 wherein the heat exchange tube is formed from a single metal sheet including two flat-wall-forming portions; a connection portion connecting the two flat-wall-forming portions and adapted to form the first side wall; two side-wall-forming elongated projections provided integrally with and in such a manner as to project from corresponding side ends of the flat-wall-forming portions on sides opposite the connection portion, and adapted to form the second side wall; and a plurality of partition-wall-forming elongated projections provided integrally with the flat-wall-forming portions in such a manner as to project in the same direction as the side-wall-forming elongated projections;   the heat exchange tube is formed by folding the metal sheet at the connection portion into a hairpin form such that the side-wall-forming elongated projections butt against each other, and brazing the butting side-wall-forming elongated projections together; and   the partition-wall-forming elongated projections of at least either flat-wall-forming portion form the partition walls.   
   
   
       6 . An evaporator comprising a plurality of heat exchange tubes each assuming a flat form, the heat exchange tubes being arranged at intervals along a left-right direction with a width direction of the heat exchange tubes coinciding with a front-rear direction, the heat exchange tubes extending in a vertical direction, and each of the heat exchange tubes having a plurality of refrigerant channels arranged along the width direction,
 the evaporator satisfying a relation 0.558≦A≦1.235, where A is a value in pieces/mm obtained by dividing the number N of the refrigerant channels of the heat exchange tube by a width W of the heat exchange tube as measured in the front-rear direction and is expressed by A=N/W.   
   
   
       7 . An evaporator comprising a plurality of heat exchange tubes each assuming a flat form, the heat exchange tubes being arranged at intervals along a left-right direction with a width direction of the heat exchange tubes coinciding with a front-rear direction, the heat exchange tubes extending in a vertical direction, and each of the heat exchange tubes having a plurality of refrigerant channels arranged along the width direction,
 the evaporator satisfying a relation 0.35≦Dh≦1.0, where Dh is an equivalent diameter in mm of the heat exchange tube.   
   
   
       8 . An evaporator according to  claim 6  or  7 , wherein each of all the refrigerant channels of the heat exchange tube excluding two refrigerant channels located at widthwise opposite ends has an elongated protrusion formed on an inner peripheral surface of the refrigerant channel and extending in a longitudinal direction of the refrigerant channel. 
   
   
       9 . An evaporator according to  claim 6  or  7 , wherein each of all the refrigerant channels of the heat exchange tube excluding two refrigerant channels located at widthwise opposite ends has a rectangular cross section, and a corner portion of the rectangular cross section has a radius R of 0.1 mm or less. 
   
   
       10 . An evaporator according to  claim 6  or  7 , wherein each of the heat exchange tubes comprises two flat walls in parallel with each other; first and second side walls extending between and over corresponding side ends of the two flat walls; and partition walls provided between the first and second side walls and extending between the two flat walls and in a longitudinal direction of the two flat walls for separating the adjacent refrigerant channels from each other;
 the heat exchange tube is formed from a single metal sheet including two flat-wall-forming portions; a connection portion connecting the two flat-wall-forming portions and adapted to form the first side wall; two side-wall-forming elongated projections provided integrally with and in such a manner as to project from corresponding side ends of the flat-wall-forming portions on sides opposite the connection portion, and adapted to form the second side wall; and a plurality of partition-wall-forming elongated projections provided integrally with the flat-wall-forming portions in such a manner as to project in the same direction as the side-wall-forming elongated projections;   the heat exchange tube is formed by folding the metal sheet at the connection portion into a hairpin form such that the side-wall-forming elongated projections butt against each other, and brazing the butting side-wall-forming elongated projections together; and   the partition-wall-forming elongated projections of at least either flat-wall-forming portion form the partition walls.   
   
   
       11 . An evaporator according to  claim 6  or  7 , further comprising:
 a refrigerant inlet/outlet header tank having a refrigerant inlet header section and a refrigerant outlet header section arranged in juxtaposition in the front-rear direction;   a refrigerant turn header tank disposed below and apart from the refrigerant inlet/outlet header tank and having a first intermediate header section opposed to the refrigerant inlet header section, and a second intermediate header section opposed to the refrigerant outlet header section and communicating with the first intermediate header section; and   a heat exchange core section formed between the refrigerant inlet/outlet header tank and the refrigerant turn header tank;   wherein the heat exchange core section comprises a heat exchange tube group consisting of a plurality of heat exchange tubes arranged at intervals in a longitudinal direction of the refrigerant inlet/outlet and turn header tanks and connected, at opposite end portions, to the refrigerant inlet/outlet and turn header tanks, and fins each disposed between adjacent heat exchange tubes;   two or more heat exchange tube groups are arranged between the refrigerant inlet/outlet and turn header tanks and in juxtaposition in an air flow direction; and   the heat exchange tubes of at least one heat exchange tube group are connected between the refrigerant inlet header section and the first intermediate header section, and the heat exchange tubes of at least one heat exchange tube group are connected between the refrigerant outlet header section and the second intermediate header section.