A heat exchanger includes a plurality of longitudinally-extending first channels and a plurality of second channels fluidly isolated from the plurality of first channels. Each first channels includes a plurality of spiraling internal fins and a plurality of external fins. The internal fins extend from and are integrally formed with the internal walls of the first channel. The external fins connect extend from and are integrally formed with the external walls of the first channels, connecting channels together. The plurality of second channels is defined in part by external walls of the plurality of first channels and the plurality of external fins.

A method for manufacturing a heat exchanger includes preparing heat exchange tubes by using an aluminum extrudate made of an alloy containing Mn (0.1 to 0.3 mass %), and Cu (0.4 to 0.5 mass %), the balance being Al and unavoidable impurities; preparing fins by using an aluminum bare material made of an alloy containing Mn (1.0 to 1.5 mass %) and Zn (1.2 to 1.8 mass %), the balance being Al and unavoidable impurities; causing Zn, Si, and flux powders to adhere to the outer surfaces of the heat exchange tubes such that the Zn powder adhesion amount becomes 2 to 3 g/m.sup.2, the Si powder adhesion amount becomes 3 to 6 g/m.sup.2, and the flux powder adhesion amount becomes 6 to 24 g/m.sup.2; and brazing the heat exchange tubes and the fins together by utilizing the Si powder and the flux powder adhered to the outer surfaces of the heat exchange tubes.

A heat exchanger includes a plurality of longitudinally-extending first channels and a plurality of second channels fluidly isolated from the plurality of first channels. Each first channels includes a plurality of spiraling internal fins and a plurality of external fins. The internal fins extend from and are integrally formed with the internal walls of the first channel. The external fins connect extend from and are integrally formed with the external walls of the first channels, connecting channels together. The plurality of second channels is defined in part by external walls of the plurality of first channels and the plurality of external fins.

A return bend for use in a heater treater, production separator, or furnace is designed to join adjacent tubes. The return bend includes a pipe constructed in a continuous piece. The pipe includes: a first end forming a first opening of the pipe facing a first direction; a second end opposite the first end, the second end forming a second opening facing the first direction; and at least one curving section that bends with a continuously smooth curvature of the pipe wall from the first end to the second end.

An evaporation heat transfer tube has a tube main body and a step-like structure; outer fins are arranged at intervals on the outer surface of the tube main body and an inter-fin groove is formed between two adjacent outer fins; the step-like structure respectively abuts against the bottom plane and one of the side walls of the inter-fin groove. The step-like structure has a first surface, a second surface and at least one flange formed by the intersection of the two surfaces, wherein the first and the second surface intersect respectively with the side wall and the bottom plane.

A double tube and the like includes: a cylindrical outer tube; a cylindrical inner tube including a helical protrusion in an outer circumferential surface, the inner tube being provided inside the outer tube; and a helical flow passage forming member that forms a helical flow passage inside the inner tube, the helical flow passage forming member being provided inside the inner tube.

A heat exchanger includes a plurality of longitudinally-extending first channels and a plurality of second channels fluidly isolated from the plurality of first channels. Each first channels includes a plurality of spiraling internal fins and a plurality of external fins. The internal fins extend from and are integrally formed with the internal walls of the first channel. The external fins connect extend from and are integrally formed with the external walls of the first channels, connecting channels together. The plurality of second channels is defined in part by external walls of the plurality of first channels and the plurality of external fins.

The present invention relates to an evaporation heat transfer tube with a hollow cavity, comprising a tube main body and at least one hollow frustum structure. Outer fins are arranged at intervals on the outer surface of the tube main body and inter-fin grooves are formed between two adjacent outer fins. The hollow frustum structure is arranged at the bottom of the inter-fin grooves and surrounded by side walls. The top of the hollow frustum structure is provided with an opening. The side walls extend inwards and upwards from the bottom of the inter-fin grooves and thus the area of the opening is less than the area of the bottom of the hollow frustum structure. The inner surface and the outer surface of the side walls are intersected at the opening to form a flange. Preferably, the flange is a sharp corner and the radius of the curvature is 0 to 0.01 mm. The side walls are formed by at least two surfaces which are connected to each other. The hollow frustum structure is hollow pyramid frustum shaped, hollow volcano shaped or hollow cone frustum shaped. The height Hr and the height H of the inter-fin grooves meet the following relations: Hr/H is greater than or equal to 0.2. The present invention is ingeniously designed and concisely structured and it remarkably enhances the boiling coefficient between the outer surface of the tube and the liquid outside the tube, reinforcing the heat transfer in boiling and it is suitable for large-scale popularization and application.

The anticorrosion treatment method of the invention is carried out on the outer surface of an aluminum extruded heat exchange tube which is formed of an Al alloy containing Mn 0.2 to 0.3 mass %, Cu 0.05 mass % or less, and Fe 0.2 mass % or less, and which has a wall thickness of 200 m or less. The anticorrosion treatment method includes applying a specific dispersion of a flux powder and a Zn powder onto the outer surface of the heat exchange tube, and vaporizing a liquid component of the dispersion, to thereby deposit the Zn powder and the flux powder on the outer surface of the heat exchange tube, such that the Zn powder deposition amount, the flux powder deposition amount, and the ratio of the flux powder deposition amount to the Zn powder deposition amount are adjusted to specific values.

A heat exchanger 10 which generally includes a heat transfer passage 12 coupled to a plurality of heat transfer fins 14. The heat transfer passage 12 is a generally tubular member having an outer wall 20 having an internal passage 22 configured to receive a first heat transfer fluid (e.g., liquid coolant). As illustrated, the heat transfer passage 12 is generally serpentine, but it will be appreciated the heat transfer passage 12 may have any suitable configuration. The plurality of heat transfer fins 14 are arranged such that spaces 24 are defined between adjacent fins 14 to receive a second heat transfer fluid (e.g., ambient air). In operation, thermal energy from a first heat transfer fluid is passed through the heat transfer passage 12 to the heat transfer fins 14 whereby a second heat transfer fluid receives and dissipates the thermal energy, or vice versa.