Patent Application
20130025835
The present disclosure relates to heat exchangers, and more particularly to heat exchangers which are suitable for use as oil coolers in heavy vehicles.
The disclosure relates particularly to heat exchangers which are of a so-called single-flow integrated type, i.e. heat exchangers which provide for an integrated flow of one medium (heat emitting medium), whereas the heat exchanger is substantially immersed in another medium (e.g. cooling medium).
A heat exchanger for use as an oil cooler in e.g. heavy vehicles may be formed from a plurality of parallel plates, which are stacked, such that parallel channels are formed between the plates. Typically, every second one is arranged to carry a flow of cooling medium, and the other channels are arranged to carry a flow of heat-emitting medium. The plates may be brazed together to form a single heat-exchanger unit.
The basic principle for forming such a heat exchanger is disclosed in e.g. WO90/13394A1 and W02004027334A1.
When in use, the heat exchanger is typically arranged in a cavity, through which the cooling medium is caused to flow, while heat-emitting medium is fed through an inlet opening of the heat exchanger, through the channels for the heat-emitting medium, after which the cooled heat-emitting medium is extracted through an outlet opening of the heat exchanger. Hence, the channels for the cooling medium are open to the cavity.
Due to vibrations and manufacturing tolerances, there is always a space between the walls confining the cavity and the heat exchanger. This space will cause some of the cooling medium to bypass the heat exchanger, thus negatively affecting its efficiency.
GB2130354A discloses how a sealing strip comprising a rubber-elastic material may be used to prevent the cooling medium from bypassing the heat exchanger.
Similarly, DE4020454A1 discloses how a plurality of sealing lips may be arranged to prevent the cooling medium from bypassing the heat exchanger.
U.S. Pat. No. 6,516,874 B2 discloses how a plurality of shims and baffle clips may be arranged to close the longitudinal sides of the heat exchanger, thus effectively preventing the cooling medium from bypassing the heat exchanger.
There is a need for an improved heat exchanger, which is suitable for use as an oil cooler in e.g. heavy vehicles.
It is an object of the present disclosure to provide a heat exchanger, which is suitable for use as an oil cooler in a heavy vehicle. It is a particular object to provide a more efficient heat exchanger. Yet another object is to provide a heat exchanger which is robust and easy to install.
The invention is defined by the appended independent claims. Embodiments are set forth in the dependent claims, in the following description and in the drawings.
According to a first aspect, there is provided a heat exchanger for an oil cooler, comprising: at least two heat exchanger members, enclosing a first channel; wherein a second channel is formed between the two heat exchanger members. An edge portion of a first one of the heat exchanger members presents a bypass restrictor extending towards an edge portion of a second one of the heat exchanger members, and the bypass restrictor forms an outer wall of the heat exchanger.
The bypass restrictor will at least partially close the second channel, thus preventing or reducing bypass flows to or from said second channel. The bypass restrictor may also form an outer, or outwardly facing, wall of the heat exchanger.
The bypass restrictors will steer or eliminate flow at the perimeter of the heat exchanger members. By preventing or reducing bypass flows, the heat rejection of the heat exchanger is improved.
The bypass restrictor may extend continuously along said at least a part of said edge portion of said first one of the heat exchanger members.
By “extending continuously” is meant that the bypass restrictor presents a substantially constant cross section over a portion of its extension.
The bypass restrictor may extend substantially in parallel with a main flow direction in the second channel.
In particular, the bypass restrictor may extend along at least ¼, ⅓, ½, ⅔ or ¾ of a length of the second channel.
The bypass restrictor may, along its extension, provide a substantially continuous seal against the second one of the heat exchanger members. By “substantially continuous” it is understood that the seal may be continuous but for some minor leaks, which may be caused by tolerances or brazing defects.
The edge portion may be an edge portion which extends substantially in parallel with a main flow direction in the second channel, such as e.g. a longitudinal edge portion.
The heat exchanger plates may be joined together along the entire periphery thereof, thereby effectively closing the first channel.
The bypass restrictor may be in contact with the edge portion of the second one of the heat exchanger members.
The bypass restrictor may thus completely prevent bypass flow.
The bypass restrictor may be joined with the edge portion of the second one of the heat exchanger members.
Such joining may be achieved by welding or brazing, thus effectively also forming the connection between the heat exchanger members. The need for a separate bolt to hold the units together is thus eliminated.
The bypass restrictor may be provided by the edge portion of the heat exchanger member being folded to form a flange.
For example, the flange may be formed by folding one or both of the heat exchanger plates forming the heat exchanger member.
As an alternative, the bypass restrictor may be formed by a ridge in the immediate vicinity of the edge of one or both of the heat exchanger plates forming the heat exchanger member.
The ridge may be formed on the edge of the plate, or it may be slightly spaced from the edge. Typically, the ridge extends in parallel with the edge of the heat exchanger member. The spacing from the edge may be in the order of 1-5 mm, preferably 1-2 mm.
At least one of the heat exchanger members may be formed by a pair of joined together heat exchanger plates.
As one alternative, at least one of the heat exchanger members may be formed by a substantially tubular body.
At least one of an inlet and an outlet of the second channel is open to a cavity in which the heat exchanger is to be placed.
Hence, the coolant is introduced into the cavity, and then caused to flow through the heat exchanger package. According to a second aspect, there is provided an oil cooling system, comprising a cavity having a liquid cooling medium inlet and a liquid cooling medium outlet; an oil inlet for oil to be cooled and an oil outlet for cooled oil; a heat exchanger, as described above, said heat exchanger being substantially enclosed in said cavity.
The outer wall of the heat exchanger may be spaced from a corresponding wall of the cavity.
A flow restrictor may be arranged to prevent the cooling medium from flowing outside the outer wall of the heat exchanger.
According to a third aspect, there is provided a method for cooling oil in a vehicle using an oil cooling system as described above, the method comprising causing the oil to be cooled to flow from the oil inlet through the first channel to the oil outlet, and causing liquid cooling medium to flow from the cooling medium inlet through the second channel to the cooling medium outlet.
In the method, some of the liquid cooling medium may be caused to flow outside the outer wall of the heat exchanger.
In the method, some of the liquid cooling medium may be caused to flow between the bypass restrictor and the edge portion of the second one of the heat exchanger members.
In the method, some of the liquid cooling medium may be at least partially, preferably entirely, prevented from flowing between the bypass restrictor and the edge portion of the second one of the heat exchanger members.
As an alternative, the liquid cooling medium may be prevented from flowing outside the outer wall of the heat exchanger.
a and 1b are schematic sectional views of the heat exchanger stack of
c is a schematic perspective view of a heat exchanger plate forming part of the heat exchanger stack of
d is a schematic sectional view of another embodiment of the bypass restrictor.
e is a schematic sectional view of yet another embodiment of the bypass restrictor.
a and 2b are schematic sectional views of the heat exchanger stack of
The heat exchanger 1 presents an outer wall 2, which is formed by flanges 11 of the heat exchanger members 10. The flanges form bypass restrictors.
In the embodiment illustrated in
Referring to
An edge portion of each heat exchanger member is folded to provide the flange 11. In the embodiment illustrated in
c schematically illustrates a heat exchanger plate 18 designed for a coolant flow which is substantially parallel with the long edges of the heat exchanger plate, and which thus is entirely open at its short edges.
Referring to
As illustrated in
As mentioned above, as an alternative, and as illustrated in
a and 2b schematically illustrates the configuration of each heat exchanger member 10′ of this embodiment. As can be seen at the right portion of
It is also possible to join the heat exchanger members 10′ to each other by fastening the ridge 11′ to the ridge 11′ of the adjacent heat exchanger member 10′, e.g. by brazing, soldering or welding. Glue may also be used to achieve such fastening. It is possible to provide a sealant to seal the space between the ridges.
Referring to
Referring to
The plates 17, 18; 17′, 18′; 17″, 18″ forming the heat exchanger member may be joined by brazing or welding, as is conventional.
Furthermore, the heat exchanger members 10, 10′, 10″ may be joined together by brazing or welding about the ports 3, 4 and optionally also peripherally by the flange 11, 11′, 11″ of one heat exchanger member being brazed or welded to the periphery of an adjacent heat exchanger member.
Referring to
The oil to be cooled may enter port 4 and exit at port 3 via channel 12, thus flowing in the direction indicated by Fo. It is noted that the flows Fo and Fc may be arranged in the same direction or as counter flows.
Referring to
shows a heat exchanger formed by a plurality of heat exchanger members 10′″a, 10′″b, each of which is formed as a substantially tubular member have a flange extending along its length direction. Each member may be formed by rolling or folding a piece of sheet metal or by extrusion. In either case, the forming of the tubular member may be followed by a flattening step and/or by insertion of an additional flange structure to increase heat transfer.
The heat exchanger may be formed as illustrated by a plurality of identical heat exchanger members, which are arranged such that their respective flange form all or a part of an outer wall. The heat exchangers members are arranged such that every the flange of every second heat exchanger member form part of the right outer wall and the flanges of the remaining heat exchanger members form a respective part of the left outer wall.
The length of the flange may vary according to various embodiments. In the illustrated embodiment, each flange has a length corresponding to the distance to the second to next heat exchanger member. However, longer flanges are conceivable, for example a length corresponding to the n to next heat exchanger member, where n is an even number.
In yet another alternative, the heat exchanger members forming the outermost heat exchanger members may have a respective flange, each of which forming a respective outer wall, while the remaining heat exchanger members have no flange at all, but are enclosed by the flanges of the two outermost heat exchanger members.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1050342-3 | Apr 2010 | SE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SE2011/050418 | 4/7/2011 | WO | 00 | 10/5/2012 |
