HEAT TRANSFER PIPE FOR HEAT EXCHANGER
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.