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The present invention relates to a plate heat exchanger, and more particularly a plate heat exchanger having at least two types of heat exchanger plates stacked to form flow channels between them with projections protruding from the plane of the plate connected to the adjacent heat exchanger plate.
Plate heat exchangers having projections from the plates are known, for example, from FIG. 8 of EP 742 418 B1 (prescribed there as oil coolers). They are also known from numerous other publications for other types of applications, including DE 100 34 343C2, DE 201 19 565 U1 and U.S. Pat. No. 4,781,248.
Internal inserts, as opposed to projections formed in the plates themselves, are also often used with plate heat exchangers. However, such inserts often can cause difficult to remove residues to remain in the flow channels, including, for example, fine metallic chips that form during production of the internal inserts. If such residues reach the oil loop, for example, they can lead to failure of the system. Despite this, however, better heat exchange efficiency can often be achieved with internal inserts over heat exchangers in which the plate bottoms are shaped. In addition, internal inserts often enjoy advantages over the mentioned shapes with respect to strength of the plate heat exchanger (especially its resistance to high internal pressures) since the inserts may be metallically connected over a relatively large area to the opposite plate bottoms of the heat exchanger plates.
The present invention is directed toward overcoming one or more of the problems set forth above.
According to one aspect of the present invention, a plate heat exchanger is provided including first and second sets of heat exchanger plates. The plates of the second set are alternately stacked with the plates of the first set of plates to form flow channels therebetween. The first set of heat exchanger plates have first projections protruding in one direction from the plane of the plates and second projections protruding in the opposite direction from the plane of the plate. The second set of heat exchanger plates have third projections protruding in the one direction from the plane of the plates of the second set. The first projections are connected to the adjacent heat exchanger plate of the second set and the second projections narrow the flow channel by protruding into the space between at least two of the third projections.
In one form of this aspect of the present invention, the first projections are connected to adjacent heat exchanger plates by solder.
In another form of this aspect of the present invention, the first and second projections have an identical form. In an alternate form of this aspect of the present invention, the first and second projections have different configurations from one another.
In still another form of this aspect of the present invention, the number, configuration and arrangement of the first and second projections are selected to optimize heat exchanger strength and heat exchange efficiency.
In yet another form of this aspect of the present invention, the plates of both sets are trough-like with a protruding edge and inserted one in the other to connect on the edge.
According to another form of this aspect of the present invention, the second projections are spaced from and not connected to the plates of the second set of plates.
According to yet another form of this aspect of the present invention, the second protrusions are connected to the adjacent heat exchanger plate of the first set.
According to still another form of this aspect of the present invention, the first projections lie against the plane of the adjacent plate of the second set of heat exchanger plates.
According to another form of this aspect of the present invention, the first and second projections have the same height (h), in opposite directions, from the plate from which they protrude. According to an alternate form, the first projections have a first height in one direction from the plate, and the second projections have a second height in the opposite direction from the plate, and the first and second heights are different.
According to yet another form of this aspect of the present invention, height (H) of the third projections from the second set plates is greater than the height (h) of the first and second projections from opposite sides of the first set plates.
According to still another form of this aspect of the present invention, all of the plates of the first and second sets have at least four openings forming four channels through the stacked plates, two of the channels serving for feed or discharge of oil and the other two for feed or discharge of a coolant. In further forms, annular deformations are provided around the openings for selectively defining and blocking passages between the plate opening channels and the flow channels formed between the plates, and/or deflecting deformations are provided only partially around the plate openings of at least two of the plate opening channels to deflect the oil and/or coolant.
According to yet another form of this aspect of the present invention, the flow channels in which the first projections protrude are provided for coolant and the other flow channels into which the second projections protrude are provided for oil.
The heat exchanger 20 includes stacked heat exchanger plates 22, 24 having four openings 26-29 that form four channels 30-33 in the plate heat exchanger, which serve to supply or discharge oil and coolant.
The elements of the plate heat exchanger may advantageously be made from aluminum sheet having an expedient solder coating, and the heat exchanger plates 22, 24 may be advantageously produced from aluminum sheet with a sheet thickness of about 0.3 mm by means of suitable sheet deformation methods.
The heat exchanger plates 22, 24 are designed trough-like with a continuous raised edge 36 therearound, with the stacked plates 22, 24 sealed around the raised edges 36 and the plate heat exchanger 20 sealed on the top by a cover plate 38 and on the bottom by a base plate 40. The connections for the two heat exchange media may be provided in the base plate 40, which may also function to fasten the plate heat exchanger to another element (e.g., by holes 41). Knobs 42 may also be provided on the base plate 40 to assist in positioning the stack of heat exchanger plates 22, 24 on base plate 40.
The cover plate 38 is illustrated in
Heat exchanger plate 22 is of special significance here. It has first projections 50 and second projections 62 that protrude in the opposite direction from the plane of the plate 52. Roughly square or rectangular second projections 62 extend upward from the plane of the plate 52 in
The rectangular projections 62 have a gradation 68, which is readily apparent from the enlarged depiction in
In the depicted practical examples, the height h of the projections 60 and 62 is identical, but it should be appreciated that this is not essential to the present invention. The height h of the projections 62 in an undepicted practical example could be identical to the height H of the projections 76, in which case the projections 62 would lie against the heat exchanger plate 24 and could be connected to it.
Positioning of the individual projections 60, 62 in the illustrated embodiment may advantageously be in different alternating rows 80, 82 viewed in the longitudinal direction 84 of the plate 22. For example, as illustrated, rows 80 that are formed only from square projections 62 and alternating rows 82 include alternating circular projections 60 and square projections 62. The rows 80, 82 may advantageously be arranged as mirror images of each other relative to the center 86 of the heat exchanger plate 22. It should be understood, however, that a different sequence and arrangement of projections 60 and 62 could also be chosen within the scope of the present invention, with optimization of the arrangement occurring by achievement of minimal pressure loss with simultaneously high heat exchange efficiency. It should further be understood that the form of the projections 60, 62 and 76 (e.g., round or oval, square or rectangular, elongated arc-like, with or without gradation 68, or with more than one gradation 68) can also be varied from those shown in the Figures within the scope of the present invention.
A number of circular projections 60 may be concentrated in the plate bottom 54 in the region 90 between openings 26, 27 and 28, 29, as illustrated in
The described two types of trough-like heat exchanger plates 22, 24 are stacked one in the other alternately so that the flow channels 72 for oil and flow channels 78 for coolant are produced between the heat exchanger plates 22 and 24 (see
The arrows in
A top view of the second type of heat exchanger plate 24 is shown in
As can be seen from
In accordance with the present invention, a plate heat exchanger 20 may be adapted to provide suitable strength and heat exchange efficiency for a stipulated application without having to provide internal inserts in the flow channels. As a result, good results can be achieved both in terms of internal pressure stability and heat exchange efficiency, without the contamination drawbacks potentially present when internal inserts are used.
By appropriate positioning and configuration of the projections 60, 62, 76, internal pressure stability may be achieved by the connected projections 60, 76 and improved heat exchange efficiency may be achieved by the projections 60, 62, 76 as well (with the projections increasing the heat-exchanging surfaces and increasing the flow rate of the medium by constricting the channel so that the mentioned improvement in heat exchange efficiency is achieved). The increase in surface available for heat exchange is achieved, for example, in the flow channel 72 by the projections 62.
Further, it should be appreciated that the elimination of inserts/turbulence plates according to the present invention allows the heat exchanger 20 to be produced more favorably in an automated process. Only two different types of heat exchanger plates need be stacked, one on the other, to provide for simplification and cost reduction in manufacturing.
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.