U.S. patent application number 15/154941 was filed with the patent office on 2017-11-16 for heat exchanger with dummy tubes.
The applicant listed for this patent is DENSO THERMAL SYSTEMS S.p.A.. Invention is credited to Andrea PAROLA.
Application Number | 20170328637 15/154941 |
Document ID | / |
Family ID | 60294538 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170328637 |
Kind Code |
A1 |
PAROLA; Andrea |
November 16, 2017 |
Heat exchanger with dummy tubes
Abstract
Heat exchanger comprising a pair of headers and a plurality of
parallel and coplanar tubes interconnecting the headers, wherein
each header comprises a header plate provided with a plurality of
slots, in each of which an end of a respective tube is fitted, and
wherein the heat exchanger is configured to prevent fluid from
flowing into at least one tube, hereinafter dummy tube, arranged at
a boundary between functionally different sections of the heat
exchanger. The slot of the header plate which receives the end of
the respective dummy tube is formed as a blind recess in the header
plate.
Inventors: |
PAROLA; Andrea; (Poirino,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO THERMAL SYSTEMS S.p.A. |
POIRINO |
|
IT |
|
|
Family ID: |
60294538 |
Appl. No.: |
15/154941 |
Filed: |
May 13, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 2021/0094 20130101;
F28D 1/0443 20130101; F28F 9/0202 20130101; F28F 1/126 20130101;
F28F 9/0209 20130101; F28F 2270/02 20130101; F28D 1/05325
20130101 |
International
Class: |
F28D 1/053 20060101
F28D001/053; F28F 9/02 20060101 F28F009/02; F28F 1/12 20060101
F28F001/12; F28F 9/02 20060101 F28F009/02; F28F 13/00 20060101
F28F013/00 |
Claims
1. A heat exchanger comprising a pair of headers and a plurality of
parallel and coplanar tubes interconnecting the headers, wherein
each header comprises a header plate provided with a plurality of
slots, in each of which an end of a respective tube is fitted, and
wherein the heat exchanger is configured to prevent fluid from
flowing into at least one tube, hereinafter dummy tube, arranged at
a boundary between functionally different sections of the heat
exchanger, wherein the slot of the header plate which receives the
end of the respective dummy tube is formed as a blind recess on the
header plate, the end of the respective dummy tube being closed by
an integral portion of the header plate.
2. A method for manufacturing a header plate for a heat exchanger
as claimed in claim 1, comprising the following steps: subjecting a
plate to a forming operation so as to produce a plurality of
deformed areas on the plate, each of which defines a blind recess,
and subjecting the plate to a material removal operation so as to
produce through-apertures in the deformed areas of the plate, the
deformed areas which have the through-apertures constituting the
slots intended to receive the ends of respective tubes of the heat
exchanger, wherein the material removal operation in one or more of
the deformed areas which constitute the slots intended to receive
the ends of respective dummy tubes is omitted.
3. The method as claimed in claim 2, wherein said forming operation
comprises a deep-drawing operation.
4. The method as claimed in claim 2, wherein said material removal
operation comprises a punching operation.
Description
[0001] The present invention relates to a heat exchanger comprising
a pair of headers and a plurality of parallel and coplanar tubes
interconnecting the headers, wherein each header comprises a header
plate provided with a plurality of slots, in each of which an end
of a respective tube is fitted, and wherein the heat exchanger is
configured to prevent fluid from flowing into at least one tube,
hereinafter dummy tube, arranged at a boundary between functionally
different sections of the heat exchanger.
[0002] The invention relates in particular to the sector of heat
exchangers for automobile engine cooling systems.
[0003] It is known to use radiators for the thermal treatment of
the engine cooling fluid, in order to keep the engine at the
optimum working temperature.
[0004] In particular, radiators which are divided into two or more
functionally different sections in order to improve the cooling
performance are known. For example, in this connection radiators
characterized by a U flow of the cooling liquid are known, a first
section of the radiator (which covers some of the tubes) being
intended for the outward flow, and a second section (which covers
the remainder of the tubes) being intended for the return flow of
the cooling liquid. By way of a second example, so-called composite
radiators are known, these being formed by single radiator bodies
connected to separate high-temperature and low-temperature
circuits, wherein a first section of the radiator (which covers
some of the tubes) is connected to the high-temperature circuit,
and a second section of the radiator (which covers the remainder of
the tubes) is connected to the low-temperature circuit.
[0005] In the aforementioned cases, in the different sections of
the radiator there exist different flows of the coolant at
different temperatures, with the same or opposite flow directions.
The sections of the exchanger are therefore at different
temperatures; however, since they are in contact with each other
within the same exchanger they may thermally influence each
other.
[0006] In view of this drawback solutions have been proposed for
improving the efficiency of a heat exchanger by preventing the
thermal influence between adjacent or consecutive sections. In this
connection, solutions have been proposed where the heat exchanger
is configured to prevent the flow of fluid inside at least one
tube, generally called a dummy tube, arranged at a boundary between
functionally different sections of the heat exchanger.
[0007] For example, JP 2008-175508 A and JP 2002-115991 A are known
solutions of composite heat exchangers in which the dummy tubes are
created by placing partitions inside the headers which prevent the
cooling fluid from being able to reach these tubes.
[0008] JP 2012-241600 discloses a solution where it is also
envisaged placing, inside a composite radiator, a barrier block for
preventing the dummy tubes from being effectively passed over by a
cooling air flow.
[0009] In any case, in the known solutions, the creation of dummy
tubes requires the positioning of partitions inside the headers.
This represents a complication in the production process of the
exchanger. Moreover, the solution which envisages the use of
partitions cannot be used to create dummy tubes in a U-flow
exchanger since the presence of a partition inside the
recirculation header would create an interruption which would
hinder the flow of the fluid.
[0010] In order to solve the problem of using partitions inside
headers, it has been proposed to use dummy tubes which have a
length smaller than that of the other tubes, so as not to perforate
the header plates at the ends of these dummy tubes. This solution
has however proved to be unsatisfactory owing to the difficulty of
processing tubes of different lengths in automatic assembly
machines.
[0011] One object of the invention is therefore to provide a
solution for forming dummy tubes in a heat exchanger which is the
simplest and most economical possible.
[0012] Another object of the invention is to provide a solution
which may be used in exchangers with different flow configurations,
in particular in U-flow exchangers.
[0013] These objects are achieved according to the invention by a
heat exchanger of the type defined initially, in which the slot in
the header plate which receives the end of the respective dummy
tube is formed as a blind recess in the header plate, the end of
the dummy tube being closed by an integral portion of the header
plate.
[0014] Preferred embodiments of the invention are defined in the
dependent claims which are to be understood as forming an integral
part of the present description.
[0015] Further characteristic features and advantages of the
invention will become clearer from the following detailed
description of an embodiment of the invention, provided with
reference to the accompanying drawings which are provided purely by
way of a non-limiting example and in which:
[0016] FIG. 1 is a schematic front elevation view of a heat
exchanger according to the invention;
[0017] FIG. 2 is a cross-sectional view, on a larger scale, of the
exchanger according to FIG. 1; and
[0018] FIG. 3 is a schematic front elevation view of another heat
exchanger according to the invention;
[0019] With reference to FIG. 1, this shows a heat exchanger
indicated overall by 1. In the example shown the heat exchanger 1
is a liquid/air heat exchanger, which in the automobile sector is
generally referred to as a radiator.
[0020] The heat exchanger 1 comprises a pair of headers 10, 20 and
a plurality of parallel and co-planar tubes 30, 30' which
interconnect the headers 10, 20. Fins 40 are arranged between
adjacent tubes 30, 30'.
[0021] With reference to FIG. 1, each header 10, 20 comprises a
header plate 11, 21 made of metallic material and a header tank 12,
22 fixed to the respective header plate 11, 21 in a manner
conventional per se, for example by means of braze-welding or
riveting of the edges of the plate onto the edges of the respective
tank.
[0022] A plurality of slots 50, 50' is formed in each header plate
11, 21, one end of a respective tube 30 30' being inserted in each
of said slots. Each tube end is joined to either plate by means of
a material connection, for example braze-welding, at each slot.
[0023] In the example shown, the heat exchanger 1 is an exchanger
which has a U flow of the heat exchange fluid. One of the headers,
denoted by 10 in FIG. 1, is therefore a fluid inlet and outlet
header and is divided into an inlet section 12a and an outlet
section 12b which are separated from each other by a partition 15
arranged inside the header 10. 16a and 16b indicate respectively a
fluid inlet and a fluid outlet arranged on the inlet section 12a
and on the outlet section of the first header 10 so as to connect
the heat exchanger to an external system. The other header 20 shown
in FIG. 1 is a recirculation header; the tubes 30 connected to the
inlet section 12a of the first header 10 therefore convey the heat
exchange fluid between the first header 10 and the second header
20, while the tubes 30 connected to the outlet section 12b of the
first header 10 convey the heat exchange fluid back from the second
header 20 to the first header 10.
[0024] Inside the heat exchanger 1, therefore, two functionally
different sections are identified: an outward section and a return
section for the heat exchange fluid. The broken line B in FIGS. 1
and 2 indicates in graphical form the boundary between these two
sections.
[0025] According to another embodiment of the invention (shown in
FIG. 3), the heat exchanger is a so-called composite exchanger. In
this case, each of the headers 10, 20 is divided into sections
(two, in the example shown in FIG. 3) separated from each other by
partitions 15 and 25 arranged respectively inside the first header
10 and the second header 20. In particular, the first header 10
comprises a first inlet section and a second inlet section, each of
which has a respective fluid inlet 16a and 16a', and the second
header comprises a first outlet section and a second outlet
section, each of which has a respective fluid outlet 26b, 26b';
inside the same heat exchanger, therefore, several functionally
different sections are defined, for example one section for
conveying high-temperature fluid and another section for conveying
low-temperature fluid. The broken line B in FIG. 3 indicates in
graphical form the boundary between these two sections.
[0026] The heat exchanger 1 is configured to prevent the flow of
fluid inside at least one tube, indicated by 30' in the figures,
arranged in the region of the boundary B between functionally
different sections of the heat exchanger 1. The tubes in which the
conveying of heat exchange fluid is prevented are known in the
sector as dummy tubes and allow the thermal zones of the heat
exchanger to be kept separate, preventing any mutual thermal
influence and thus improving the performance features of the heat
exchanger.
[0027] In the heat exchanger described above, the dummy tubes 30'
are entirely identical to the other tubes 30 which form the
plurality of parallel and coplanar tubes of the heat exchanger. The
flow of the heat exchange fluid to the dummy tubes 30' is prevented
by the fact that, in the header plates 11, 21, each slot, indicated
by 50', which receives the end of the respective dummy tube 30' is
formed as a blind recess in the header plate 11, 21, differently
from the other slots, indicated by 50, which are formed as
through-apertures. The end of the dummy tube 30' is therefore
closed by an integral portion of the header plate, in other words a
portion, in particular a deformed portion, which forms part of the
same plate part.
[0028] The configuration described above may be produced
industrially in an extremely simple and low-cost manner.
[0029] In fact, in order to manufacture the header plates 11, 21, a
plate conventionally undergoes a forming operation, in particular a
deep-drawing operation, in order to form a plurality of deformed
areas on the plate, each of which defines a blind recess.
[0030] The plate is then subjected to a material removal operation,
in particular a punching operation, in order to form
through-apertures in the deformed areas of the plate, the deformed
areas provided with the through-apertures forming the slots 50
intended to receive the ends of respective tubes 30 of the heat
exchanger.
[0031] In order to realize the configuration of dummy tubes
described above it is merely required to omit the material removal
operation in one or more of the deformed areas which form the slots
50' intended to receive the ends of respective dummy tubes 30'.
[0032] To this end it is sufficient to modify or program the
machine intended for the material removal (punching) operation such
that it does not carry out the material removal operation in the
deformed areas intended to form the blind-recess slots 50'. A same
machine may therefore be adapted in an extremely simple manner to
different header-plate configurations.
[0033] The dedicated moulds for forming the internal partitions in
the header are therefore not needed, these being instead required
in the known solutions and, among other things, being normally
suitable only for a few types of header.
[0034] Moreover, as can be seen in the example shown, dummy tubes
may also be provided in U-flow heat exchangers, something which
would not be possible if separating partitions are arranged inside
the recirculation header.
[0035] Moreover as can be seen, the present invention does not
require the use of tubes of smaller length tubes for manufacture of
the dummy tubes and therefore allows tubes all with the same length
to be used. This aspect is particularly desirable with a view to
automatic assembly of the heat exchanger.
* * * * *