Heat transfer pipe for refrigerant mixture

Abstract

To provided a high heat transfer performance with a heat transfer pipe used to a condenser and an evaporator in a refrigerating cycle using a refrigerant mixture, the heat transfer pipe includes main grooves and auxiliary grooves each formed on the inner surface of the heat transfer pipe with the main grooves intersecting the auxiliary grooves, wherein a length of ribs, which are divided into sections by the auxiliary grooves, of ridges formed along the direction of the main grooves is made longer than the length of the ridges, a width of the auxiliary grooves is made smaller than the length of the ribs and further the auxiliary grooves are formed in a direction where a pressure gradient in the heat transfer pipe is reduced.

1 . A heat transfer pipe used for a condenser and an evaporator in a refrigerating cycle using a refrigerant mixture, comprising main grooves and auxiliary grooves each formed on the inner surface of said heat transfer pipe with said main grooves intersecting said auxiliary grooves, 
 wherein said main grooves are separated by ridges, and said ridges are divided into ribs by said auxiliary grooves,    wherein a length of said ribs formed along the direction of said main grooves is made longer than a width of said ridges, a width of said auxiliary grooves is made smaller than the length of said ribs and further said auxiliary grooves are formed in a direction where a pressure gradient in said heat transfer pipe is reduced,    wherein said main grooves are formed by being inclined at an angle in a range from 7° to 25° with respect to said pipe axis, and    wherein said auxiliary grooves are formed at a spiral angle in a range of ±5° with respect to a pipe axis.    
     
     
         2 . A heat transfer pipe according to  claim 1 , wherein said auxiliary grooves are formed in parallel with said pipe axis.  
     
     
         3 . In a refrigerating apparatus comprising a refrigerating cycle using a refrigerant mixture flowing through a condenser and an evaporator, the improvement comprising at least one of said condenser and evaporator including a heat transfer pipe formed on an inner surface with main grooves and auxiliary grooves intersecting with said main grooves, 
 wherein said main grooves are separated by ridges, and said ridges are divided into ribs by said auxiliary grooves,    wherein a length of said ribs formed along the direction of said main grooves is made longer than a width of said ridges, a width of said auxiliary grooves is made smaller than the length of said ribs and further said auxiliary grooves are formed in a direction where a pressure gradient in said heat transfer pipe is reduced,    wherein said main grooves are formed by being inclined at an angle in a range from 7° to 25° with respect to said pipe axis, and    wherein said auxiliary grooves are formed at a spiral angle in a range of ±5° with respect to a pipe axis.    
     
     
         4 . A refrigerating apparatus according to  claim 3 , wherein said auxiliary grooves are formed in parallel with said pipe axis.