Folded tube for a heat exchanger and method of making same

Abstract

The present invention relates to a multi-port folded tube for a heat exchanger, and, in particular, a multi-port condenser tube and a method of making thereof. The present invention further comprises a folded tube and method of making a multi-port folded tube for a heat exchanger wherein at least one tube locking feature is included.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to heat exchangers for motor vehicles and, more specifically, to a folded tube and method of making same for a heat exchanger, such as an condenser, in a motor vehicle. DESCRIPTION OF THE RELATED ART [0002] It is known to provide a tube for a heat exchanger such as a condenser in an air conditioning system of a motor vehicle. The tube typically carries a first fluid medium in contact with its interior while a second fluid medium contacts its exterior. Typically, the first fluid medium is a liquid or a two-phase liquid and gas mixture and the second fluid medium is a gas. Where a temperature difference exists between the first and second fluid mediums, heat will be transferred between the two via heat conductive walls of the tube. [0003] In addition, it is known to provide multi-port tubes for condensers in an air conditioning system in a vehicle. Such tubes often have small hydraulic diameter ports for heat transf...

AI Technical Summary

Benefits of technology

[0020] One advantage of the present invention is that a multi-port folded tube for a heat exchanger with such a locking feature can be used on with a variety of heat exchangers. In the case such as a condenser is provided for an air conditioning system of a motor vehicle for condensing liquid refrigerant. Another advantage of the present invention is that the folded tube is stamped and folded and is more economical to manufacture than an extruded tube. Yet another advantage of the present invention is that the folded tube has half webs that do not extend the entire height of the ports to be formed, and, therefore, do not require compression to make a folded top or folded bottom tube portion alone that has to extend to the opposing top or bottom tube portion respectively. Still another advantage of the present invention is that a method of making the folded tube is provided whereby various tube-end locking features may be utilized. Yet a further advantage of the present invention, particularly in preferred embodiments, is that it provides a preformed end and support versus a ‘traditional’ closed end form that allows seams to be formed and held more closely together, thus eliminating the potential of multiple pin-hole sized ‘gaps’ at the end seams of the folded tube. Since the gap is relatively closed, brazing to a header slot, for example, becomes more efficient and the folded tube more desirable for these applications.

Problems solved by technology

However, these sort of extruded tubes have the disadvantages of requiring internal dimensions that must have wide tolerances, in order to keep the extrusion dies life span at a reasonable level to be practical, i.e. tighter tolerances generally reduce die life, whereas the requirement of wider tolerances of most extruded tubes of this nature means that there is increased material usage, and, the extruded tubes, therefore, are relatively expensive to produce.

However, in those ‘solutions’ several other problems have been discovered: tube gauge might be not optimized since this rigid relationship provides that once tube height is determined, tube gauge is determined also, but not fully due to the structural requirement; this relationship does not allow the use of potential future stronger materials, since reducing the gauge to meet the same structural requirement would not be possible due to the rigid height gauge relationship; and the reduced flexibility in tube design for different applications is less advantageous due to the fact that heat exchanger tube design must consider both heat transfer and airside pressure drop.

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