U.S. patent application number 10/895208 was filed with the patent office on 2005-02-24 for turbulator for heat exchanger.
Invention is credited to Brost, Viktor.
Application Number | 20050039899 10/895208 |
Document ID | / |
Family ID | 33483000 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050039899 |
Kind Code |
A1 |
Brost, Viktor |
February 24, 2005 |
Turbulator for heat exchanger
Abstract
The efficiency of dimple-type turbulators located on roughly
parallel walls defining a flow channel within a heat exchanger is
increased by providing protuberances on the dimples themselves
which enhance turbulence, and thus, increase the rate of heat
exchange.
Inventors: |
Brost, Viktor; (Aichtal,
DE) |
Correspondence
Address: |
WOOD, PHILLIPS, KATZ, CLARK & MORTIMER
500 W. MADISON STREET
SUITE 3800
CHICAGO
IL
60661
US
|
Family ID: |
33483000 |
Appl. No.: |
10/895208 |
Filed: |
July 20, 2004 |
Current U.S.
Class: |
165/167 |
Current CPC
Class: |
F28F 1/40 20130101; F28F
3/044 20130101; F28F 3/12 20130101 |
Class at
Publication: |
165/167 |
International
Class: |
F28F 003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 22, 2003 |
DE |
DE 103 33 177.8 |
Claims
What is claimed is:
1. In a heat exchanger having at least one flow channel for a heat
exchange fluid defined by spaced, generally parallel walls between
which the heat exchange fluid flows and a plurality of dimples
formed in at least one of the walls to extend therefrom toward the
other wall to be secured thereto or to another dimple extending
from said other wall toward said one wall and wherein the dimples
act as turbulators to induce turbulence in the heat exchange fluid
as it flows between the generally parallel walls, the improvement
comprising protrusions on sides of said dimples extending into said
flow channel(s) to increase the inducement of turbulence in said
heat exchange fluid as it flows between said parallel walls and
around said dimples.
2. The heat exchanger of claim 1 wherein said walls are aluminum
sheets and said dimples and said protrusions are formed by a metal
forming die.
3. The heat exchanger of claim 1 wherein said dimples have bases
integral with at least one of said walls and opposite flat tops
bonded to the other of said walls or to the flat top of another of
said dimples, and said protrusions are ribs extending from the base
to the flat top of the dimples.
4. The heat exchanger of claim 3 wherein each dimple has a
plurality of said ribs spaced from one another about the periphery
of the dimple.
5. The heat exchanger of claim 4 wherein the ribs on each dimple
are generally radially oriented.
6. The heat exchanger of claim 1 wherein said dimples have bases
integral with at least one of said walls and opposite flat tops
bonded to the other of said walls or to the flat top of another of
said dimples, and said protrusions on said dimple are located
between the base and flat top of the corresponding dimple.
7. The heat exchanger of claim 6 wherein there is at least one
protrusion on a dimple which is in the form of a rib extending from
the base of the dimple to the top thereof.
8. The heat exchanger of claim 6 wherein said walls are formed of a
thermally conductive metal and said dimples are die-formed in at
least one of said walls, said protrusion being integral with said
sheet and die-formed in said dimples.
Description
FIELD OF THE INVENTION
[0001] This invention relates to heat exchangers, and more
particularly to improved turbulators for heat exchangers.
BACKGROUND OF THE INVENTION
[0002] For many years, various types of turbulators have been
employed in the flow channels for one or more heat exchange fluids
in a heat exchanger. The turbulators induce turbulence in the flow
of the heat exchange fluid through the channel and as is well
known, the resulting increased turbulence increases the heat
exchange coefficient, which, in turn, increases the rate of heat
transfer.
[0003] Turbulators come in many shapes and forms. In some cases,
the turbulators are manufactured as elements separate from other
constituents of the heat exchanger and are placed in a fluid flow
channel at the time of assembly of the heat exchanger with which
they are to be used. In other cases, turbulators are formed in the
walls that define a flow channel. This type of turbulator is
frequently found in so-called plate heat exchangers, drawn cup heat
exchangers, and in heat exchangers utilizing so-called flattened
tubes. In each of these types of heat exchangers, two or more
generally parallel walls of high thermal conductivity, along with
other constituents, define one or more channels. Dimple-like
turbulator structures are formed in one or both of the walls. In
some cases, where the dimples are formed in only one wall, they
will extend entirely across the channel to contact and typically be
bonded to the opposite wall to improve the strength of the heat
exchanger.
[0004] In some cases, dimples will be formed in both walls and
extend across the flow channel to be bonded to the opposite wall,
again to provide strength. In still other cases, the dimples will
be aligned with each other and formed in both walls in which case
the dimples extend only half-way across the flow channel and then
are bonded to one another, again to provide strength to the heat
exchanger.
[0005] A typical plate heat exchanger having dimples which serve as
turbulators formed in only one wall of the flow channel is
illustrated in European patent Publication EP 0 263 798 B1. An
example of dimples formed on both walls and extending partway
across the flow channel to be bonded t one another is illustrated,
for example, in European patent Publication EP 0 418 227 B1.
[0006] As mentioned in the '798 European patent publication, and as
mentioned above, it is common to provide turbulator plates in
various flow channels. The plates can be formed with a significant
variety of structure that can be adapted to the particular heat
exchange requirements. However, from a manufacturing standpoint,
the provision of separate turbulators is not the preferred choice
because separate parts are involved that must be produced and
inserted into the flow channels, thus complicating production and
assembly.
[0007] Another restriction that hampers the use of separate
turbulators is that in many applications, a great degree of
cleanliness of the flow channels is required and residues used to
bond the separate turbulators in place can have deleterious effects
on the entire system.
[0008] Thus, there is a real need for improved turbulator
configurations where the turbulators are integrally formed with a
wall or walls of a heat exchanger flow channel to avoid the
problems associated with the use of separate turbulators and yet
provide enhanced performance and adaptability to different heat
exchange requirements that is more readily achievable with separate
turbulators.
SUMMARY OF THE INVENTION
[0009] The principal object of the invention is to provide a new
and improved turbulator structure for use in the flow channels of
heat exchangers. More particularly, it is an object of the
invention to provide a new and improved turbulator that is
integrally formed with the walls defining a flow channel in a heat
exchanger.
[0010] An exemplary embodiment of the invention achieves the
foregoing objects in a heat exchanger having at least one flow
channel for a heat exchange fluid defined by spaced, generally
parallel walls between which the heat exchange fluid flows. A
plurality of dimples are formed in at least one of the walls to
extend therefrom toward the other wall to be secured thereto or to
another dimple extending from the other wall toward the one wall.
The dimples, as is conventional, act as turbulators to induce
turbulence in the heat exchange fluid as it flows between the
generally parallel walls. The invention specifically contemplates
the provision of protrusions on the sides of the dimples that
extend into the flow channel or channels to increase the inducement
of turbulence in the heat exchange fluid as it flows between the
parallel walls and around the dimples.
[0011] In one embodiment, the walls are aluminum sheets and the
dimples and the protrusions are formed by a metal-forming die.
[0012] The invention contemplates that the dimples have bases
integral with at least one of the walls and opposite flat tops
bonded to the other of the walls or to the flat top of another of
the dimples.
[0013] In one embodiment of the invention, the protrusions on the
dimples are located between the base and flat top of the
corresponding dimple.
[0014] In a preferred embodiment, the protrusions are ribs that
extend from the base to the flat top of the dimples.
[0015] In one embodiment, each dimple has a plurality of the ribs
spaced from one another about the periphery of the dimple.
[0016] A preferred embodiment contemplates that the ribs on each
dimple are generally radially oriented. In a highly preferred
embodiment, as mentioned previously, the dimples are die-formed in
at least one of the walls and the protrusions are integral with the
sheet of which the wall is formed and die-formed in the
dimples.
[0017] Other objects and advantages will become apparent from the
following specification taken in connection with the accompanying
drawings.
DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is comprised of FIG. 1a and FIG. 1b and illustrates
fragmentary cross sections of the turbulence inducing protrusions
of the invention. FIG. 1a and FIG. 1b are representative cross
sections taken approximately along the line 1-1 in FIG. 2;
[0019] FIG. 2 is a fragmentary section taken approximately along
the line 2-2 in FIG. 3 or 4;
[0020] FIG. 3 is a plan view of a turbulator dimple with enhanced
turbulating inducing protrusions made according to the invention
according to one embodiment thereof;
[0021] FIG. 4 is a view similar to FIG. 3 but of a modified
embodiment of a turbulence-inducing structure made according to the
invention;
[0022] FIG. 5 illustrates flow channels employing turbulators
according to the invention in one form of a heat exchanger;
[0023] FIG. 6 is a fragmentary view showing still another example
of turbulators made according to the invention; and
[0024] FIG. 7 is a fragmentary, perspective view of a heat
exchanger plate embodying turbulators made according to the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] In considering the invention, it must be kept in mind that
same is not limited to any one specific type of heat exchanger.
While it will most often be used in plate heat exchangers, drawn
cup heat exchangers, or heat exchangers employing flattened tubes,
those skilled in the art will readily appreciate that the same is
susceptible to use in any sort of heat exchanger wherein flow
channels are defined by two, generally parallel walls in which
turbulating dimples can be formed. Hence, no restriction to any
particular type of heat exchanger is intended except insofar as
expressly stated in the appended claims.
[0026] With the foregoing in mind, reference is made to FIG. 7,
which shows a fragmentary perspective view of one type of heat
exchanger, specifically, a housingless plate type heat exchanger
with which the invention can be used. Specifically, one plate used
in the formation of such a heat exchanger is illustrated and
includes a base or wall section 10 surrounding by a somewhat
trapezoidally shaped flange 12. At the corners, ports 14, 16, for
two different heat exchange fluids are illustrated and the manner
in which such ports 14, 16 are connected to like ports in other
plates that are generally identical in the overall configuration
that is shown in FIG. 7 is well known and forms no part of the
present invention.
[0027] Projecting upwardly from the wall 10 is a pattern of a
plurality of dimple-like turbulators 18 to be described in greater
detail hereinafter. The pattern can take on any of a plurality of
different forms depending upon the heat exchange requirements of
the heat exchanger, the type of flow, i.e., cross current, counter
current, or concurrent, etc., the overall resistance of the flow
path within the heat exchanger, etc.
[0028] As is well known, the plates shown in FIG. 7 are frequently
stacked as illustrated in FIG. 5 to form adjacent flow channels and
as a consequence, the wall 10 may be provided with downwardly
directed dimples 20 at various locations and in a desired pattern
to provided for turbulation in an adjacent flow channel.
[0029] Referring to FIG. 5, it is seen that a second plate 22 also
provided with a peripheral flange 24 substantially identical with
the flange 12 is nested within the flange 12 and abutted to flat
tops 26 of the turbulators 18. Typically, the plates 10 and 22 are
formed of aluminum, although other highly heat-conductive metals
could be used as well. Braze alloy (not shown) is located at the
interface of the flanges 12, 24 and the point of contact between
the flat tops 26 of the dimples 18 and the plate 22 so that a
brazing operation will bond all of the components together. A
fluid-tight seal is thus provided between the flanges 12 and 24
making for a housingless heat exchanger while the dimples 18 are
brazed to the adjacent plate 22 to provide strength. The net result
is that connected flow channels 28 are formed about the dimples
18.
[0030] FIG. 6 illustrates a different configuration that may be
employed. In this case, both the plate 22 and the plate 10 are
provided with the dimples 18, with dimples extending in opposite
directions towards each other and with the plates 10 and 22 bonded
together at points of abutment.
[0031] As can be seen in both FIGS. 5 and 6, the dimples 18 are
provided with protrusions 30 that are made according to the
invention, and will now be described. Referring to FIG. 3, the flat
top of each dimple 26 is illustrated and it will be seen that the
flat top is connected by a generally frustoconical sidewall 32 to a
base 34 which is, in reality, one or the other or both of the
plates 10, 22. That is to say, the base 32 is integral with the
plates and the frustoconical sidewall and top 26 integral with the
plates 10 and 22 as well. The protuberances 30 are formed in the
sidewall 32 and extend from the base 34 to the flat top 26 at
radially spaced locations. The protuberances, in the embodiment
illustrated in FIG. 3, are in the form of ribs which extend
generally radially from the center of the flat top 26.
[0032] FIG. 4 shows a somewhat similar configuration but rather
than having a frustoconical sidewall, the same is an oblong
sidewall 36 that decreases in dimension as one moves from the base
34 to the flat top 26. Again, a plurality of ribs are on the
protuberances 30, and the same are generally radially extending
from the top 26 to the base 34.
[0033] FIGS. 1a, 1b, and FIG. 2 show the protuberances 30 in cross
section.
[0034] FIGS. 1a and 1b show that the rib-like protuberances 30 may
have relatively sharp apexes as desired. It will also be
appreciated that with the dimples 18 being die-formed from the
plates 10, 22, that the protuberances 30 can be simultaneously
formed using a concave die of the desired configuration operating
against radially outer surface 40 of each dimple 18 as shown in
FIG. 1a and a convex die operating against the radially inner
surface 42 of each dimple 18 as shown in FIG. 1b.
[0035] It should be noted that the protuberances 30 need not be in
the form of ribs as shown in FIGS. 2, 3, and 4. They will, however,
be formed of any kind of an interruption or almost micro fine
structure located on the walls 32 or 36 at a location between the
base 34 and the flat top 26 of each dimple.
[0036] It is also observed that with two heat exchange fluids
flowing in opposite sides of a plate, as, for example, the plate 10
as shown in FIG. 7, that the down turned dimples 20 may have
different configurations and orientations from the upturned dimples
18 and different protrusions 30 as well to achieve desired heat
exchange characteristics. Similarly, it is possible to use the
dimples with the protuberances in only the flow channels handing
one heat exchange fluid and not the other.
[0037] The presence of the protrusions greatly enhances the
turbulating effect provided the dimples like those shown at 18 or
20 but without the protrusions 30 to achieve efficiencies more
comparable to those achieved with the use of separate turbulators
without the attendant disadvantage of the use of separate parts
requiring additional assembly and/or contamination problems as a
result of extensive bonding operations.
[0038] Typically, the protuberances 30 can be in the millimeter
range, and with such a height, will enhance the bonding of the flat
tops 26 to the plates 20, 22.
* * * * *