Heat exchanger core and corrugated rib
A heat exchanger core with the front substantially vertical and facing cooling air flow, with at least one row of flat tubes through which a liquid or gas flows, and corrugated ribs arranged in between the flat tubes. The ribs have wave flanks defining channels, each channel being for cooling air flow between an air inlet on the front of the core and an air outlet on the rear of the core. The wave flanks are at an angle β which is oblique to the core front and rear whereby the air inlet of each channel is offset relative to the corresponding air outlet. The wave flanks may also be a single arc. Corrugated ribs with wave flanks having an oblique slope angle relative to the edges of the metal sheet and louvers protruding from the plane of the wave flanks may also be included.
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot applicable.
REFERENCE TO A MICROFICHE APPENDIXNot applicable.
TECHNICAL FIELDThe present invention is directed toward heat exchangers, and particularly toward heat exchanger cores having flat tubes with ribs therebetween.
BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ARTHeat exchangers are well known in the art. In the automotive and other fields, for example, heat exchangers typically include a core consisting of a plurality of tubes carrying a liquid or gas fluid with corrugated ribs disposed between the tubes. Collecting tanks are typically connected to the ends of the tubes to facilitate re-circulation of the fluid through the associated system (e.g., engine block) and then back through the heat exchanger tubes. The fins are heated by their contact with the fluid carrying tubes, and the cooling air takes away heat by cooling the fins.
Due to the advantages of minimized weight and size in many environments, particularly automobile engine compartments, a variety of structures have been proposed to provide efficient heat exchange in compact and lightweight heat exchangers. Among those proposals is the heat exchanger disclosed in U.S. Pat. No. 5,505,257, which is directed to heat exchangers which are tilted at an angle α from vertical 10 rather than normal to the flow of cooling air as is sometime necessitated by space constraints (as illustrated in
The present invention is directed toward overcoming one or more of the problems set forth above.
SUMMARY OF THE INVENTIONAccording to one aspect of the invention, a heat exchanger core is provided with the front substantially vertical and facing cooling air flow. The core includes at least one row of flat tubes through which a liquid or gas flows, and corrugated ribs arranged in between the flat tubes. The ribs have wave flanks defining channels, each channel being for cooling air flow between an air inlet on the front of the core and an air outlet on the rear of the core. The wave flanks are at an angle β which is oblique to the core front and rear whereby the air inlet of each channel is offset relative to the corresponding air outlet.
In one form of this aspect of the present invention, the wave flanks are substantially planar with louvers in a significant section of the wave flanks protruding from the plane of the flank. In a further form of this aspect of the present invention, the louvers have an angle of bending defining protrusions in a common direction from the wave flank plane, with the angle of bending of each louver being substantially the same. In a still further form, the louvers have an angle of bending defining protrusions in opposite directions from the wave flank plane whereby half of the louvers are sloped in the direction of cooling air flow and the other half are sloped against the cooling air direction, the angle of bending of each louver being substantially the same. In yet another further form, a connector has edges bent at an angle corresponding to angle of bending of the louvers, with the connector being substantially in the center of the section of the wave flanks having louvers.
In a further form of this aspect of the present invention, the surface of the wave flanks is substantially flat.
In another form of this aspect of the present invention, the wave flanks have a curved contour between the air inlet and air outlet.
In another aspect of the present invention, a corrugated rib for a heat exchanger core is provided, where the corrugated rib is formed by rolling a longitudinally extending metal sheet and includes wave flanks defining cooling flow channels therebetween. The wave flanks have an oblique slope angle relative to the edges of the metal sheet and further include louvers protruding from the plane of the wave flanks.
In one form of this aspect of the present invention, the surfaces of the wave flanks are substantially flat.
In another form of this aspect of the present invention, the surfaces of the wave flanks are a contour consisting of a single arc.
In still another form of this aspect of the present invention, the louvers are fields of louvers arranged generally parallel and close to each other.
In still another aspect of the present invention, a heat exchanger core oriented with the front substantially vertical and facing cooling air flow is provided, the core including at least one row of flat tubes through which a liquid or gas flows and corrugated ribs arranged in between the flat tubes. The ribs have wave flanks defining channels, each channel being for cooling air flow between an air inlet on the front of the core and an air outlet on the rear of the core. The air inlet of each channel is aligned relative to the corresponding air outlet with the wave flanks between such inlets and outlets having a contour consisting of a single arc.
In one form of this aspect of the present invention, louvers protrude from the surface of the wave flank in a significant section of the wave flanks.
BRIEF DESCRIPTION OF THE DRAWINGS
A heat exchanger 30 according to the present invention is illustrated in
The gas or liquid flowing in the flat tubes 44 is cooled by cooling air flowing through corrugated ribs 46 firmly bonded to the flat tubes 44 (e.g., by soldering) to together form the heat exchanger grate or core such as is generally well known in the art.
In accordance with the present invention, the corrugated ribs 46 include wave flanks 50 which define channels 52 therebetween, with the channels 52 being laid out so that the corresponding air inlet 54 into each of the channels 52 is offset relative to the corresponding air outlet 56 from each of the channels 52. As illustrated in the embodiment of
With an offset 60 between inlets 54 and outlets 56 such as shown in
Louvers 64 may also be advantageously provided in the wave flanks 50 for heat exchange efficiency whereby air turbulence may be improved without undesirably increasing the pressure loss of the cooling air stream. As illustrated in
Where louvers 64 are provided such as illustrated, it should be appreciated that the channels 52 will not be discrete, whereby an air particle entering a channel 52 through its inlet 54 may not emerge through the corresponding outlet 56. As a result, at least one part of the cooling air can be distributed to adjacent channels before it leaves the heat exchanger core again at the outlets.
The louvers may be advantageously configured to protrude from the plane of the wave flanks 50 running with the slope angle, with the heat exchanger core arranged with a slope to the direction of flow of the cooling air.
It should be appreciated that the depicted heat exchanger 10 may be designed with or without a tube bottom.
Since the corrugated ribs 46 in the depicted
The angle β2 between the wave direction 70 and the horizontal 60 is present when a heat exchanger grate or core is arranged vertically with the flat tubes 44 extending horizontally (it being understood that the direction of flow of the cooling air is generally horizontal. In these cases as well, the cooling air stream naturally impinges on one of the narrow sides of flat tube 44 to then flow through the corrugated ribs 46.
It should thus be appreciated that the present invention may offer improved efficiency of heat exchange for the common situation in which the heat exchanger core may be mounted perpendicular to the direction of air flow. According to one aspect of the invention, the channels of the corrugated ribs are formed by the corrugated flanks so that the corresponding air inlet into each of the channels is arranged offset relative to the corresponding air outlet from each of the channels. In vertical flat tubes with corrugated ribs according to the invention the air can no longer flow horizontally through the channels, as in the prior art, since it is diverted by the vertical offset. If, on the other hand, horizontal flat tubes with corrugated ribs in-between are chosen according to the invention, the horizontally-flowing cooling air is diverted according to the offset in the horizontal. In either case, each air particle is forced to intensive contact with the wave flanks. Further, increased heat exchange intensity is achieved as a result of a longer connection path between the corrugated rib and the broad sides of the flat tubes, causing more intense heat exchange because it runs obliquely to the longitudinal axis of the flat tube.
Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.
Claims
1. A heat exchanger core, said heat exchanger core being oriented with the front substantially vertical and facing cooling air flow, said core comprising:
- at least one row of flat tubes through which a liquid or gas flows;
- corrugated ribs arranged in between said flat tubes, said ribs having wave flanks defining channels, each channel being for cooling air flow between an air inlet on the front of said core and an air outlet on the rear of said core;
- wherein said wave flanks are at an angle β which is oblique to said core front and rear whereby said air inlet of each channel is offset relative to the corresponding air outlet.
2. The heat exchanger core of claim 1, wherein said wave flanks are substantially planar, and further comprising louvers in a significant section of the wave flanks protruding from the plane of the flank.
3. The heat exchanger core of claim 2, wherein said louvers have an angle of bending defining protrusions in a common direction from the wave flank plane, said angle of bending of each louver being substantially the same.
4. The heat exchanger core of claim 2, wherein said louvers have an angle of bending defining protrusions in opposite directions from the wave flank plane whereby half of the louvers are sloped in the direction of cooling air flow and the other half are sloped against the cooling air direction, said angle of bending of each louver being substantially the same.
5. The heat exchanger core of claim 2, further comprising a connector having edges bent at an angle corresponding to angle of bending of said louvers, said connector being substantially in the center of the section of the wave flanks having louvers.
6. The heat exchanger core of claim 1, wherein the surface of the wave flanks is substantially flat.
7. The heat exchanger core of claim 1, wherein said wave flanks have a curved contour between said air inlet and air outlet.
8. A corrugated rib for a heat exchanger core, said corrugated rib being formed by rolling a longitudinally extending metal sheet and comprising wave flanks defining cooling flow channels therebetween, whereby said wave flanks have an oblique slope angle relative to the edges of the metal sheet and further comprising louvers protruding from the plane of the wave flanks.
9. The corrugated rib of claim 8, wherein the surfaces of the wave flanks are substantially flat.
10. The corrugated rib of claim 8, wherein the surfaces of the wave flanks are a contour consisting of a single arc.
11. The corrugated rib of claim 8, wherein the louvers comprise fields of louvers arranged generally parallel and close to each other.
12. A heat exchanger core, said heat exchanger core being oriented with the front substantially vertical and facing cooling air flow, said core comprising:
- at least one row of flat tubes through which a liquid or gas flows;
- corrugated ribs arranged in between said flat tubes, said ribs having wave flanks defining channels, each channel being for cooling air flow between an air inlet on the front of said core and an air outlet on the rear of said core;
- wherein said air inlet of each channel is aligned relative to the corresponding air outlet with the wave flanks between such inlets and outlets having a contour consisting of a single arc.
13. The method of claim 12, further comprising louvers protruding from the surface of the wave flank in a significant section of the wave flanks.
Type: Application
Filed: Mar 11, 2005
Publication Date: Sep 15, 2005
Inventors: Bernhard Lamich (Esslingen), Anton Zielbauer (Filderstadt), Viktor Brost (Aichtal), Jens Nies (Holzgerlingen)
Application Number: 11/078,849