Heat exchanger tube and heat exchanger employing the same

Abstract

In a compact heat exchanger, a heat exchanger tube adapted for precision assembly of an outer tube and an inner tube and free from decreasing heat transfer efficiency is provided. For this purpose, the heat exchanger tube includes: a plurality of parallel outer tubes; inner tubes inserted in the outer tubes and having their opposite ends extended outward of the outer tubes; a gap support member formed of a wire material disposed in a gap between an inner periphery of the outer tube and an outer periphery of the inner tube and making spiral contact with the inner periphery and the outer periphery substantially throughout the length of the outer tube; and a supporting member making spiral contact with an inner periphery of the inner tube throughout the length of the inner tube.

1 . A heat exchanger tube comprising:
 an outer tube;   an inner tube inserted in the outer tube;   a gap support member including a wire material which is disposed in a gap between an inner periphery of the outer tube and an outer periphery of the inner tube, and makes spiral contact with the inner periphery and the outer periphery substantially throughout the length of the outer tube; and   a supporting member including a wire material which makes spiral contact with an inner periphery of the inner tube throughout the length of the inner tube.   
     
     
         2 . The heat exchanger tube according to  claim 1 , wherein the gap support member comprises a coil material and has a wire diameter substantially equal to the gap. 
     
     
         3 . The heat exchanger tube according to  claim 1 , wherein the gap support member comprises a coil material having a small diameter portion and a large diameter portion alternately formed, and has a wire diameter smaller than the gap, a coil inside diameter at the small diameter portion defined by an outside diameter of the inner tube, and a coil outside diameter at the large diameter portion defined by an inside diameter of the outer tube, thus supporting the inner tube in the outer tube. 
     
     
         4 . A heat exchanger tube comprising:
 an outer tube;   an inner tube inserted in the outer tube;   a gap support member including a wire material which is disposed in a gap between an outer-tube inner peripheral surface and an inner-tube outer peripheral surface, and makes spiral contact with the outer-tube inner peripheral surface and the inner-tube outer peripheral surface substantially throughout the length of the outer tube;   a supporting member including a wire material which makes spiral contact with the inner-tube inner peripheral surface throughout the length of the inner tube; and   a heat transfer member which is extended centrally through the supporting member throughout the length of the supporting member and at least a part of the outer periphery of the heat transfer member is in contact with the supporting member.   
     
     
         5 . The heat exchanger tube according to  claim 4 , wherein the heat transfer member is a sheet elongated in a longitudinal direction of the supporting member and twisted spirally. 
     
     
         6 . The heat exchanger tube according to  claim 4 , wherein the heat transfer member is an outer-periphery protruding round rod including oval portions made by deforming a round outer periphery thereof at predetermined space intervals in the longitudinal direction of the supporting member. 
     
     
         7 . The heat exchanger tube according to  claim 4 , wherein the heat transfer member is a different-diameter round rod with its round outer periphery alternately formed of a small diameter portion and a large diameter portion at predetermined space intervals in the longitudinal direction of the supporting member. 
     
     
         8 . The heat exchanger tube according to  claim 4 , wherein the heat transfer member is a solid rod having a polygonal cross section. 
     
     
         9 . A heat exchanger employing the heat exchanger tube according to  claim 1 ,
 wherein a plurality of the heat exchanger tubes are arranged in mutually parallel relation,   a primary flow passage is formed by connecting all the inner-tube inlet ends to a primary branch tube and connecting all the inner-tube outlet ends to a primary collecting tube, and   a secondary flow passage is formed by connecting all the outer-tube inlet ends to a secondary branch tube and connecting all the outer-tube outlet ends to a secondary collecting tube.   
     
     
         10 . A heat exchanger employing the heat exchanger tube according to  claim 1 ,
 wherein the plurality of heat exchanger tubes are bundled, the bundle of heat exchanger tubes is housed in a cylindrical shell, a primary flow passage is formed by interconnecting inlet ends of the inner tubes and interconnecting outlet ends of the inner tubes, a secondary flow passage is formed by interconnecting inlet ends of the outer tubes and interconnecting outlet ends of the outer tubes, and an interior of the shell is configured as a tertiary flow passage.   
     
     
         11 . The heat exchanger according to  claim 10 , wherein a plurality of straightening plates having planes perpendicular to a longitudinal direction of the heat exchanger tubes are disposed in the shell so as to support the heat exchanger tubes and to make the tertiary flow passage meander.