Parallel Flow Type Heat Exchanger

Abstract

A heat exchanger is provided and includes a plurality of tubes with refrigerant passages inside of them and a pair of header tanks to which end parts of the tubes are brazed. Brazing materials, which are used for brazing to the header tanks, are arranged at the outer circumferential surfaces of the tubes. Base materials of the metal sheet members which form the header tanks are exposed at the inner circumferential surfaces and outer circumferential surfaces of the header tanks.

1 . A heat exchanger which has a plurality of tubes which is provided with refrigerant passages inside them and a pair of header tanks to which end parts of the tubes are brazed, wherein
 brazing materials which are used for brazing to the header tanks are arranged at the outer circumferential surfaces of the tubes, and   base materials of the metal sheet members which form the header tanks are exposed at the inner circumferential surfaces and outer circumferential surfaces of the header tanks.   
     
     
         2 . The heat exchanger according to  claim 1  wherein said header tanks have header plates to which said tubes are brazed and tank plates which are assembled to said header plates and wherein the base materials of the metal sheet members which form said header plates are exposed. 
     
     
         3 . The heat exchanger according to  claim 1  wherein said header tanks have an entry side header tank into which refrigerant flows and an exit side header tank from which refrigerant flows and wherein at least one of said entry side header tank or said exit side header tank is provided inside it with separators at the two surfaces of which the base materials of the metal sheet members which form said separators are exposed. 
     
     
         4 . The heat exchanger according to  claim 1  wherein said tubes are provided inside them with inner fins which have wavy shapes,
 in each said tube, a belt-shaped sheet member is folded back to form a curved end part and give different lengths to the two end parts, the folded back sheet member is formed with parallel parts, said two end parts are bent near them to form slanted parts, then are bent so that said two end parts become parallel, and a long end part of said two end parts is folded back to the short end part side and swaged, then is joined to the swaged part, whereby a flat shape is formed, and 
 each said inner fin is brazed to the inside wall surface of said tube at the bent parts of the wavy parts and is formed at one end with a flat plate part which is sandwiched between the end parts of a said belt-shaped sheet member at said swaged part to be joined with said tube. 
 
     
     
         5 . The heat exchanger according to  claim 1  wherein said plurality of tubes are provided at their outsides with outer fins for dissipating heat. 
     
     
         6 . The heat exchanger according to  claim 1  wherein the brazing material which is arranged at the outer circumferential surfaces of said tubes has an amount of Si of 3.5 wt % to 10 wt %. 
     
     
         7 . The heat exchanger according to  claim 1  wherein the brazing material which is arranged at the outer circumferential surfaces of said tubes has an amount of Si of 3.5 wt % to 7.5 wt %. 
     
     
         8 . The heat exchanger according to  claim 1  wherein said header tanks are provided with pipes which are comprised of header plates to which said tubes are brazed and tank plates which are attached to said header plates joined together and wherein the base materials of the metal sheet members which form said pipes are exposed. 
     
     
         9 . The heat exchanger according to  claim 1  wherein said header tanks are provided with pipes which are comprised of header plates to which said tubes are brazed and tank plates which are attached to said header plates joined together and wherein at least one of the inner circumferential surfaces and outer circumferential surfaces of metal sheet members which forms pipes are provided with anticorrosion layers of sacrificial materials with low potentials. 
     
     
         10 . The heat exchanger according to  claim 1  wherein said header tanks have an entry side header tank into which refrigerant flows and an exit side header tank from which refrigerant flows and wherein at least one of said entry side header tank or said exit side header tank is provided inside it with separators at least at one surface of which a brazing material is provided. 
     
     
         11 . The heat exchanger according to  claim 8  wherein said pipes have cross-sectional shapes of any of circular shapes, oval shapes, and irregular shapes. 
     
     
         12 . The heat exchanger according to  claim 2  wherein said header tanks have an entry side header tank into which refrigerant flows and an exit side header tank from which refrigerant flows and wherein at least one of said entry side header tank or said exit side header tank is provided inside it with separators at the two surfaces of which the base materials of the metal sheet members which form said separators are exposed.