Heat exchangers with corrugated heat exchange elements of improved strength

Abstract

A corrugated fin or turbulizer for a heat exchanger comprises a series of corrugations with parallel side walls. The side walls are provided with a series of parallel slits between which one-sided or two-sided louvers are defined. Each of the louvers has first and second edges extending along an adjacent pair of slits, and at least one bend located between the edges, thereby causing at least one of the edges of the louver to project outwardly of the plane of the side wall, and providing the side wall with improved crush resistance. The corrugations may preferably be rectangular or trapezoidal in form, having generally flat top and bottom surfaces defined by two closely-spaced bends. The top and bottom surfaces may preferably be provided with protrusions, at least some of which extend close to the bends. This assists in creating localized areas of weakness along which the bends can be formed cleanly.

Description

FIELD OF THE INVENTION [0001] The invention relates to heat exchangers and corrugated heat exchange elements for use therein, and particularly to corrugated heat exchanger fins and turbulizers of improved strength and manufacturability, and to heat exchangers incorporating such fins and turbulizers. BACKGROUND OF THE INVENTION [0002] Heat exchangers are commonly provided with heat exchange elements such as corrugated fins and / or turbulizers in order to enhance heat transfer between two or more fluids. Corrugated fins and turbulizers are structurally similar, and typically comprise a thin metal sheet in which parallel bends define a series of corrugations of a generally rectangular or triangular form. A turbulizer is generally inserted inside a fluid flow passage defined by the interior of a tube or a plate pair, whereas a fin is generally mounted on an exterior surface of a tube or plate pair. The fluids which come into contact with these heat exchange elements may be on the hot or ...

AI Technical Summary

Benefits of technology

The present invention provides a corrugated heat exchange element for a heat exchanger that has improved heat transfer efficiency. The heat exchange element has a plurality of side walls and top and bottom walls that define spaces for flow of a heat exchange fluid. The side walls have longitudinal bends between them, and each side wall has at least one group of adjacent louvers that create spaces for flow of the heat exchange fluid. The louvers have parallel slits and bends between the slits to improve heat transfer. The heat exchange element can be used in a plate-type heat exchanger with plates secured together to form a fluid flow passage.

Problems solved by technology

One disadvantage of the Joshi turbulizer is that the triangular or V-shaped corrugations make contact with the plates only along the relatively narrow top and bottom surfaces of the turbulizer, thereby limiting heat transfer.

Furthermore, the sloping side walls of the Joshi turbulizer result in the formation of relatively large spaces between adjacent side walls.

Where the corrugations are aligned parallel to the direction of fluid flow, there is significant duct flow between the side walls, which results in poor heat transfer.

The metal foil used in these inserts is very thin and therefore it is difficult to form clean bends along the edges of the top and bottom walls.

Due to the thinness of the foil, the heat exchange elements can be easily crushed by this compression, resulting in irreparable damage to the heat exchanger.

While the strength of the corrugated heat exchange element may be improved by the provision of louvers, this improvement is sometimes insufficient to resist crushing during assembly.

Furthermore, in conventional louvered fins or turbulizers as taught by Joshi, there is an unsupported area between the ends of the louvers and the top and bottom walls.

This unsupported area is particularly vulnerable to crushing during assembly of the heat exchanger.

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