U.S. patent application number 11/922477 was filed with the patent office on 2009-09-24 for heat exchanger for small components.
Invention is credited to Karine Brand, Florian Schopper, Oliver Woelflik.
Application Number | 20090236083 11/922477 |
Document ID | / |
Family ID | 36709974 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090236083 |
Kind Code |
A1 |
Brand; Karine ; et
al. |
September 24, 2009 |
Heat Exchanger for Small Components
Abstract
The invention relates to a heat exchanger for small components
through which a fluid may flow, made from several individual
pieces, exclusively produced by forming and joined to each other,
to an inlet channel, a planar heat exchange element and an outlet
channel. The heat exchange element comprises an upper and lower
side which may be connected to at least one heat source,
characterized in that the inlet channel is made from a metal
connector tube which continuously enlarges towards the heat
exchange element on the inlet side up to the total cross-sectional
flow area of the inlet side and face of the heat exchange element
and the outlet channel continuously tapers away from the heat
exchanger on the outlet side from the total cross-sectional flow
area of the output side end face of the heat exchanger element to a
metal connector tube. The heat exchange element comprises a
channel-like inner structure running in the flow direction to
increase the heat transfer, which runs within the element from the
lower side to the upper side.
Inventors: |
Brand; Karine; (Ulm, DE)
; Schopper; Florian; (Westerstetten, DE) ;
Woelflik; Oliver; (Blaubeuren, DE) |
Correspondence
Address: |
FLYNN THIEL BOUTELL & TANIS, P.C.
2026 RAMBLING ROAD
KALAMAZOO
MI
49008-1631
US
|
Family ID: |
36709974 |
Appl. No.: |
11/922477 |
Filed: |
June 16, 2006 |
PCT Filed: |
June 16, 2006 |
PCT NO: |
PCT/EP2006/005776 |
371 Date: |
December 18, 2007 |
Current U.S.
Class: |
165/133 ;
165/181 |
Current CPC
Class: |
F28F 3/048 20130101;
F28F 3/12 20130101; F28F 9/0263 20130101; H01L 23/473 20130101;
F28D 2021/0029 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/133 ;
165/181 |
International
Class: |
F28F 13/18 20060101
F28F013/18; F28F 1/10 20060101 F28F001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2005 |
DE |
10 2005 029 074.4 |
Claims
1. A heat exchanger (1) for small components, through which heat
exchanger (1) a fluid can flow, comprising a plurality of
individual parts which are produced exclusively by forming and are
firmly connected to one another by joints to form an inlet channel
(2), a flat heat-exchanging element (3) and an outlet channel (4)
with the heat-exchanging element (3) having an upper face and lower
face which can be connected to at least one heat source,
characterized, in that the inlet channel (2) comprises a metal
connecting tube (21) which on the input side widens continuously
towards the heat-exchanging element (3) up to the entire
cross-sectional area through which flow can pass of the input-side
end face of the heat-exchanging element (3), in that the outlet
channel (4), starting from the heat-exchanging element (3) tapers
on the output side continuously from the entire cross-sectional
area through which flow can pass of the output-side end face of the
heat-exchanging element (3) to a metal connecting tube (41), and in
that the heat-exchanging element (3) has a channel-like internal
structure (31) in order to increase the heat transfer, which
internal structure (31) runs in the flow direction and extends from
the lower face to the upper face in the interior.
2. The heat exchanger as claimed in claim 1, characterized in that
the internal structure (31) is designed such that the fluid flow is
constant over the cross section.
3. The heat exchanger as claimed in claim 1, characterized in that
the internal structure (31) of the heat-exchanging element (3)
continues in the inlet channel (2) and/or in the outlet channel
(4).
4. The heat exchanger as claimed in claim 1, characterized in that
the internal structure (31) is composed of continuous ribs which
form channels.
5. The heat exchanger as claimed in claim 1, characterized in that
the internal structure (31) is composed of rods or pyramids
projecting from the inner wall.
6. The heat exchanger as claimed in claim 1, characterized in that
the heat-exchanging element (3) is formed integrally.
7. The heat exchanger as claimed in claim 1, characterized in that
the inlet channel (2) the heat-exchanging element (3) and the
outlet channel (4) are arranged aligned.
8. The heat exchanger as claimed in claim 1, characterized in that
the inlet channel (2) and/or the outlet channel (4) run pointed
away from the heat source (5).
9. The heat exchanger as claimed in claim 1, characterized in that
the inner surface is coated.
Description
[0001] The invention relates to a heat exchanger for small
components, through which heat exchanger a fluid can flow,
comprising a plurality of individual parts which are produced
exclusively by forming and are firmly connected to one another by
joints to form an inlet channel, a flat heat-exchanging element and
an outlet channel with the heat-exchanging element having an upper
face and lower face which can be connected to at least one heat
source.
[0002] Heat exchangers such as these are already used in widely
differing technical fields. Heat exchangers with liquid cooling or
vaporization are becoming increasingly important, in particular
because of the very large amount of heat emitted from
microprocessors or from high-power electronic components.
[0003] Already-available heat exchangers in the form of water
coolers for microprocessors are generally manufactured from a
copper or aluminum block, by metal-cutting machining. Since solid
material is used for the individual components, metal-cutting
machining is correspondingly complex, and therefore expensive.
[0004] One further development which uses a manufacturing method
that does not involve metal cutting is described in the document DE
103 15 225 A1. This document discloses a heat exchanger with an
element in the form of a pot and an element in the form of a cover,
the two of which can be connected to one another in order to form a
sealed internal area with two openings, through which a
heat-exchanging medium can be passed into the internal area and out
of it. The heat exchanger has a multiplicity of projections which
protrude into the internal area. The elements which are in the form
of pots or covers are formed by a cold-forming process, and
preferably by an extrusion-molding process. The projections which
protrude into the internal area result in the area along which the
cooling medium flows being appropriately large to achieve as good a
heat-exchanging performance as possible. One major aim in this
case, however, is low-cost production of large quantities.
[0005] The document JP 2005019905 A discloses a cooling device
having a heat exchanger which is used as a heat sink for
semiconductor components. The heat exchanger has an internal area
which is structured towards the heat source, in order to increase
the heat dissipation. These structures, which extend over little
height, have no significant influence on the fluid flowing in the
internal area.
[0006] In addition, the document U.S. Pat. No. 5,473,508 discloses
a heat exchanger for cooling electronic components by means of an
air flow. The heat exchanger comprises a plurality of individual
parts, which are connected firmly to one another by joints to form
an inlet channel, a flat heat-exchanging element and an outlet
channel. The closed heat-exchanging element, which comprises a
covered element and a base element, in this case makes contact with
the heat source.
[0007] The invention is based on the object of developing a heat
exchanger of the type described above and of optimizing its
heat-exchanging capability, subject to the requirement for a
low-cost production method.
[0008] The invention is reflected by the features of claim 1. The
other claims, which refer back to claim 1, relate to advantageous
embodiments and developments of the invention.
[0009] The invention includes a heat exchanger for small components
through which heat exchanger a fluid can flow, comprising a
plurality of individual parts which are produced exclusively by
forming and are firmly connected to one another by joints to form
an inlet channel, a flat heat-exchanging element and an outlet
channel with the heat-exchanging element having an upper face and
lower face which can be connected to at least one heat source, in
which the inlet channel is composed of a metal connecting tube
which widens continuously on the input side towards the
heat-exchanging element, in which the outlet channel, starting from
the heat-exchanging part, tapers on the output side continuously to
a metal connecting tube, and in which the heat-exchanging element
has a channel-like internal structure in order to increase the heat
transfer, which internal structure runs in the flow direction and
extends from the lower face to the upper face in the interior.
[0010] The invention is in this case based on the idea of the heat
exchanger being composed of a plurality of individual parts which
are produced exclusively by forming. The geometries of the
individual parts are designed such that they can be produced by a
cold forming process. In particular, in this case, it is possible,
starting from an essentially round tube cross section, to create a
widened area in the inlet channel into a conical transition, and to
create the taper for the outlet channel. In this case, the end
surface of the conically widened inlet channel is then connected by
joints to the input-side end face of the flat heat-exchanging
element, and the end face of the conically tapering outlet channel
is connected to the output-side end face of the heat exchanger. The
design options of the molding technology accordingly determine, up
to a certain extent, the geometry of the upper face and lower face
of the heat-exchanging element.
[0011] In principle, the metal connecting tube of the inlet channel
or outlet channel may have any cross-sectional shape, although it
is preferably round or oval for reasons relating to the forming
process and the flow characteristics.
[0012] The channel-like internal structure which runs in the
heat-exchanging element has an important function. This structure
extends in the internal area from the lower face to the upper face,
thus resulting in increased heat transfer.
[0013] The channel structure has also been found to be extremely
robust in response to the influence of external forces. These can
occur when a heat source is being connected to and fixed on the
heat-exchanger which, in the case of hollow internal structures,
would result in the pressure forces that are used causing the
common contact surface of the heat exchanger to be deformed by the
heat source, or even to be forced in. This would be the case in
particular if thin walls were to be considered for material saving
reasons, which are no longer designed to withstand such high
mechanical loads. In comparison to the previously used
metal-cutting processes, the forming methods in their own right
already result in a material saving, thus achieving a cost
reduction. The design configuration of the internal area, as
described above, with corresponding channel structures also makes a
further contribution to this.
[0014] In this context, the channel-like internal structures
running in the flow direction are not necessarily continuous side
walls. Pins or cuboids arranged at relatively short intervals in
the flow direction, may likewise also form an appropriate channel
structure. Overall, however, this results in an advantageous design
configuration, from the flow point of view.
[0015] Soldering processes, adhesive bonding or welding, which are
already widely used in engineering, are particularly suitable as
joining processes. The mutually abutting surfaces on the end faces
of the heat-exchanging element with the inlet channel or outlet
channel may, however, also be designed so that they can be plugged
into one another by means of grooves formed on the end faces.
[0016] Another two-part embodiment of the individual parts produced
by forming may comprise two half elements which are formed in the
longitudinal direction and need be connected to one another by
joints only in the longitudinal direction.
[0017] The particular advantage is that a heat exchanger with
correspondingly thin walls can be appropriately robust with regard
to deformation. The channels which run in the internal area in this
case carry the single-phase or two-phase fluid in a specific manner
through the heat exchanger, so that the heat-exchanging performance
is optimized for mechanical robustness. In particular, the conical
inlet and outlet channels ensure a smooth transition for uniform
fluid distribution, with very little pressure drop in the flow.
[0018] In one preferred refinement of the invention, the internal
structure can be designed such that the fluid flow is constant over
the cross section. By way of example, this can be achieved by the
channel-like internal structure having a different width, also
referred to in the following text as channels, with smaller channel
cross sections being provided in the center of the heat exchanger,
and becoming larger towards the outside, in both directions. This
results in the main flow from the inlet channel being distributed
more uniformly throughout the heat exchanger.
[0019] The physical design of the internal volume of the
heat-exchanging element is particularly important in terms of
advantageous flow conditions. For example, the internal structure
of the heat-exchanging element can advantageously be continued in
the inlet channel and/or outlet channel. This results in the fluid
being distributed appropriately into the individual channels in
order to achieve advantageous flow conditions, immediately after
passing out of the metal connecting tube into the widening part of
the heat-exchanging element. In this case, structures such as these
are preferably used in the inlet channel. On the outlet side
however, channels in the tapering part of the heat-exchanging
element can also carry the fluid flow in a specific manner and
advantageously from the flow point of view.
[0020] In a further advantageous refinement to the invention, the
internal structure may comprise continuous ribs which form
channels. Continuous ribs can be produced particularly reliably by
forming processes when the intervals between the ribs are short.
The ribs run as partition walls in the internal area from the lower
face to the upper face and form the individual longitudinally
running channels in which the fluid is carried during
operation.
[0021] The internal structure may advantageously be composed of
rods or pyramids projecting from the inner wall. However, these are
always arranged such that channel-like internal structures are
formed in the flow direction. This produces advantageous structures
from the flow point of view, which still allow a certain amount of
fluid to be exchanged with adjacent channels.
[0022] In a further preferred refinement, the heat-exchanging
element may be formed integrally. However, this is possible only
subject to specific preconditions when using the forming process on
which this is based. With an integral configuration, the channel
structure is preferably produced with continuous longitudinally
pointing ribs in the internal area. This reduces the complexity of
the joints for the heat-exchanging element. Integral
heat-exchanging elements are now just connected to the inlet
channel and to the outlet channel.
[0023] The inlet channel, the heat-exchanging element and the
outlet channel can advantageously be arranged aligned. In other
words, the elongated shape has no further bends with tight radii
and therefore assists the fluid to flow uniformly through the
entire heat exchanger.
[0024] Alternatively, however, it is also necessary to consider
designs when only a small amount of physical space is available for
the heat exchanger, for example as a heat sink for microprocessors
or other components that generate heat in a computer. The inlet
channel and/or the outlet channel can then advantageously run
pointed away from heat source. However, in general, this is
feasible only with bending radii that are as large as possible and
assist the fluid to flow with as little disturbance as
possible.
[0025] When using copper and copper alloys, it is not possible to
preclude corrosion with some of the fluids that are used. The inner
surface of the heat exchanger can then advantageously be
coated.
[0026] Further advantages and refinements of the invention will be
explained in more detail with reference to the schematic drawings,
in which:
[0027] FIG. 1 shows a view of a heat exchanger with a heat
source,
[0028] FIG. 2 shows a cross section through a heat-exchanging
element with a cover and base,
[0029] FIG. 3 shows a cross section through a heat-exchanging
element with an identically designed cover and base, and an
internal structure in which items engage in one another,
[0030] FIG. 4 shows a cross section through a heat-exchanging
element with an identically designed cover and base, and an
internal structure in which items are placed on one another,
[0031] FIG. 5 shows a cross section through a heat-exchanging
element which is formed from bases stacked one on top of the other,
with a closing cover,
[0032] FIG. 6 shows a cross section through an integral
heat-exchanging element,
[0033] FIG. 7 shows a plan view of a heat exchanger with
channel-like structures of different width,
[0034] FIG. 8 shows a plan view of a heat exchanger with
channel-like structures which continue into the inlet channel and
outlet channel.
[0035] Mutually corresponding parts are provided with the same
reference symbols in all the figures.
[0036] FIG. 1 shows a schematic view of a heat exchanger 1 with a
heat source 5. The heat exchanger 1 comprises an inlet channel 2, a
flat heat-exchanging element 3 and an outlet channel 4, which are
firmly connected to one another by joints. The heat source 5 is
arranged on the lower face of the heat-exchanging element 3. The
inlet channel 2 comprises a metal connecting tube 21 which widens
continuously on the input side towards the heat-exchanging element
3. The shape of the inlet channel illustrated in the figure can be
produced integrally by means of a forming process, for example by
extrusion molding. In this case, the joint is located on the common
touching surface between the inlet channel 2 and the
heat-exchanging element 3. The outlet channel 4, which may also be
integral, likewise comprises a collecting zone 42 and a metal
connecting tube 41. The collecting zone 42 tapers continuously to
the metal connecting tube 41. The joint is in this case located on
the common touching surface between the outlet channel 4 and the
heat-exchanging element 3.
[0037] The heat source 5 is an electronic component, for example a
microprocessor. The heat source 5 is often held by brackets or by
adhesive bonding, with intermediate layers which conduct the heat
well also being used. When intermediate layers are used, the heat
source 5 is connected to the heat exchanger 1 with a contact
pressure. In the illustrated embodiment, the inlet channel 2 and
the outlet channel 4 run pointed away from the heat source 5.
[0038] FIG. 2 shows a cross section through a two-part
heat-exchanging element 3 with a cover 32 and a base 33. The
internal structure is formed together with the base 33, and the
cover 32 is firmly joined to the base. The joints for connecting
the cover 32 and the base 33 may be in the form of welded, soldered
or adhesive joints, or else force fits. Joining processes which do
not lead to thermal or mechanical deformation of the component are
preferred.
[0039] FIG. 3 shows a cross section through a heat-exchanging
element 3 with identically designed cover 32 and base 33, and with
an internal structure 31 with parts which engage in one another.
The internal structure is in this case formed in two halves
together with the cover 32 and the base 33. For forming purposes,
this offers the advantage, for example when there are continuous
ribs of in the cover 32 and the base 33, providing coarser
structures which engage in one another after being joined together
such that correspondingly small channels are produced.
[0040] In a further refinement, FIG. 4 shows a cross section
through a heat-exchanging element 3 with an identically designed
cover 32 and base 33. When fitted to one another, the two form the
channel-like internal structure.
[0041] FIG. 5 shows a cross section through a heat-exchanging
element 3, which is formed from two bases 33 stacked one on top of
the other, with a closing cover 32. Structures such as these are
used, for example, when a heat source is arranged not only on the
upper face but also on the lower face.
[0042] FIG. 6 shows a further refinement of the heat-exchanging
element 3, which can be produced integrally by means of extrusion
molding. The integral components are preferably used for relatively
large channel structures, for manufacturing reasons. These can also
be manufactured continuously and can be cut to the appropriate
length.
[0043] FIG. 7 shows a plan view of a heat exchanger 1, cut open in
the area of the heat-exchanging element 3, with channel-like
structures of different widths. The channels of the internal
structure 31 are in this case designed such that the fluid flow is
constant over the cross section of the heat-exchanging element 3,
resulting in a uniform pressure drop in the flow direction of the
fluid.
[0044] FIG. 8 shows a plan view of a partially cut-open heat
exchanger 1 with channel-like structures which continue into the
inlet channel 2 and outlet channel 4. In this refinement, the fluid
is distributed advantageously from the flow point of view into the
individual channels of the internal structure 31 immediately after
passing out of the metal connecting tube 21 into the widening part
of the distributor zone 22 or from the tapering parts of the
collecting zone 42 of the heat exchanger 1, and is collected again
towards the metal connecting tube 41.
LIST OF REFERENCE SYMBOLS
[0045] 1 Heat exchanger [0046] 2 Inlet channel [0047] 21 Metal
connecting tube [0048] 22 Distributor zone [0049] 3 Heat-exchanging
element [0050] 31 Internal structure [0051] 32 Cover [0052] 33 Base
[0053] 4 Outlet channel [0054] 41 Metal connecting tube [0055] 42
Collecting zone [0056] 5 Heat source
* * * * *