Heat transfer pipe for heat exchanger

Abstract

The invention provides a heat transfer pipe for heat exchanger, an inner surface of the heat transfer pipe being provided alternately with a plurality of helical primary teeth ( 21, 22, 23, 24, 25, 26, 27 ) and a plurality of grooves ( 31, 32, 33, 34, 35, 36 ), each groove being disposed between adjacent primary teeth, wherein a protrusion set is provided in at least one groove ( 31, 36 ), the protrusion set comprises a plurality of protrusions ( 41 ) sequentially and intermittently disposed in an extending direction of the primary teeth, and each protrusion ( 41 ) has a radial height lower than those of the primary teeth, and wherein at least one groove having no protrusion set ( 32, 33, 34, 35 ) is provided between the adjacent ones ( 31, 36 ) of the grooves each having a protrusion set. In this way, the above heat transfer pipe suppresses significantly increasing flow resistance of a fluid, and is easy to manufacture with low manufacturing cost, at the same time of improving the efficiency of heat exchange.

1 . A heat transfer pipe ( 1 ) for heat exchanger, an inner surface of the heat transfer pipe being provided alternately with a plurality of helical primary teeth ( 2 ;  21 ,  22 ,  23 ,  24 ,  25 ,  26 ,  27 ) and a plurality of grooves ( 3 ;  31 ,  32 ,  33 ,  34 ,  35 ,  36 ), each groove being disposed between adjacent primary teeth,
 wherein a protrusion set is provided in at least one groove ( 31 ,  36 ), the protrusion set comprises a plurality of protrusions ( 41 ) sequentially and intermittently disposed in an extending direction of the primary teeth, and each protrusion ( 41 ) has a radial height lower than those of the primary teeth,   and wherein at least one groove having no protrusion set ( 32 ,  33 ,  34 ,  35 ) is provided between the adjacent ones ( 31 ,  36 ) of the grooves each having a protrusion set.   
     
     
         2 . The heat transfer pipe ( 1 ) according to  claim 1 , wherein the width of each protrusion ( 41 ) in a circumferential direction of the heat transfer pipe ( 1 ) is smaller than the width of the groove ( 31 ,  36 ) where the each protrusion is located in the circumferential direction of the heat transfer pipe ( 1 ). 
     
     
         3 . The heat transfer pipe ( 1 ) according to  claim 2 , wherein the side ( 411 ) of each protrusion ( 41 ) in the circumferential direction of the heat transfer pipe ( 1 ) is formed on a side surface ( 211 ) of one of the two primary teeth ( 21 ,  22 ,  26 ,  27 ) adjacent to the groove ( 31 ,  36 ) where the each protrusion is located. 
     
     
         4 . The heat transfer pipe ( 1 ) according to  claim 3 , wherein the side of each protrusion ( 41 ) of a same protrusion set in the circumferential direction of the heat transfer pipe ( 1 ) is formed on a side surface ( 211 ) of the same primary tooth ( 21 ,  26 ). 
     
     
         5 . The heat transfer pipe ( 1 ) according to  claim 3 , wherein the sides of adjacent protrusions ( 41 ) in a same protrusion set in the circumferential direction of the heat transfer pipe ( 1 ) are formed on side surfaces of different primary teeth. 
     
     
         6 . The heat transfer pipe ( 1 ) according to  claim 1 , wherein 4 or 5 grooves each having no protrusion set are disposed between adjacent ones of grooves each having a protrusion set. 
     
     
         7 . The heat transfer pipe ( 1 ) according to  claim 1 , wherein the section of each protrusion ( 41 ) that is perpendicular to the circumferential direction of the heat transfer pipe ( 1 ) is a trapezoidal. 
     
     
         8 . The heat transfer pipe ( 1 ) according to  claim 7 , wherein the ratios of the radial height of each protrusion ( 41 ) to the radial heights of the primary teeth are between 0.05-0.5. 
     
     
         9 . The heat transfer pipe ( 1 ) according to  claim 1 , wherein the protrusions ( 41 ) in a same protrusion set are disposed at equal intervals. 
     
     
         10 . The heat transfer pipe ( 1 ) according to  claim 3 , wherein the radial height of each protrusion ( 41 ) is gradually decreased from the side of the protrusion ( 41 ) that is formed on said side surface of the primary tooth and in the extending direction of the primary tooth. 
     
     
         11 . A heat transfer pipe ( 1 ′) for heat exchanger, an inner surface of the heat transfer pipe being provided alternately with a plurality of helical primary teeth ( 21 ′,  22 ′,  23 ′,  24 ′,  25 ′,  26 ′,  27 ′) and a plurality of grooves, each groove being disposed between adjacent primary teeth,
 wherein protrusion sets are provided in the grooves on both sides of at least one primary tooth ( 21 ′,  26 ′) in a circumferential direction of the heat transfer pipe ( 1 ′), each protrusion set comprises a plurality of protrusions ( 41 ′) sequentially and intermittently disposed in an extending direction of the at least one primary tooth ( 21 ′,  26 ′), and each protrusion ( 41 ′) has a radial height lower than that of the at least one primary tooth ( 21 ′,  26 ′), 
 and wherein at least one primary tooth ( 22 ′,  23 ′,  24 ′,  25 ′) having no protrusion set disposed on either side is disposed between adjacent ones of the primary teeth ( 21 ′,  26 ′) with protrusion sets disposed on both sides. 
 
     
     
         12 . The heat transfer pipe according to  claim 11 , wherein the width of each protrusion ( 41 ′) in the circumferential direction of the heat transfer pipe ( 1 ′) is smaller than the width of the groove where the each protrusion is located in the circumferential direction of the heat transfer pipe ( 1 ′). 
     
     
         13 . The heat transfer pipe according to  claim 12 , wherein for each primary tooth ( 21 ′,  26 ′) having protrusion sets disposed on both sides, the side of each protrusion ( 41 ′) of the protrusion sets in the circumferential direction of the heat transfer pipe is formed on one side of the each primary tooth ( 21 ′,  26 ′). 
     
     
         14 . The heat transfer pipe according to  claim 11 , wherein 4 or 5 primary teeth each having no protrusion set disposed on either side are disposed between adjacent ones of primary teeth each having protrusion sets on both sides. 
     
     
         15 . The heat transfer pipe according to  claim 11 , wherein the section of each protrusion ( 41 ′) that is perpendicular to the circumferential direction of the heat transfer pipe is a trapezoidal. 
     
     
         16 . The heat transfer pipe according to  claim 15 , wherein the ratios of the radial height of each protrusion ( 41 ′) to those of the primary teeth are between 0.05-0.5. 
     
     
         17 . The heat transfer pipe according to  claim 11 , wherein the protrusions ( 41 ′) in a same protrusion set are disposed at equal intervals. 
     
     
         18 . The heat transfer pipe according to  claim 13 , wherein the radial height of said each protrusion ( 41 ′) of the protrusion sets is gradually decreased from the side of the protrusion ( 41 ′) that is formed on said side surface ( 211 ′) of the primary tooth ( 21 ′) and in the extending direction of the primary tooth.