U.S. patent application number 14/341012 was filed with the patent office on 2015-01-29 for heat exchanger and heat exchange device.
The applicant listed for this patent is YUTAKA GIKEN CO., LTD.. Invention is credited to Toru HISANAGA, Kozue SUZUKI, Takashi WAGATSUMA.
Application Number | 20150027666 14/341012 |
Document ID | / |
Family ID | 52389476 |
Filed Date | 2015-01-29 |
United States Patent
Application |
20150027666 |
Kind Code |
A1 |
HISANAGA; Toru ; et
al. |
January 29, 2015 |
HEAT EXCHANGER AND HEAT EXCHANGE DEVICE
Abstract
A heat exchanger including a tubular core case, a pair of end
plates for closing opposite ends of the core case, and a plurality
of heat exchange tubes supported at opposite ends thereof by the
end plates and allowing flow of a first heating medium inside
thereof. One end plate is disposed on an upstream side of the first
heating medium as an upstream end plate while the other end plates
is disposed on a downstream side of the first heating medium as a
downstream end plate. The downstream end plate comprises a
downstream bottom surface part for supporting downstream end parts
of the heat exchange tubes, and a downstream wall part formed
integrally with and rising from a peripheral edge of the downstream
bottom surface part, and a top end part of the downstream wall part
is oriented toward upstream of the flow of the first heating
medium.
Inventors: |
HISANAGA; Toru;
(Hamamatsu-shi, JP) ; SUZUKI; Kozue;
(Hamamatsu-shi, JP) ; WAGATSUMA; Takashi;
(Hamamatsu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
YUTAKA GIKEN CO., LTD. |
Hamamatsu-shi |
|
JP |
|
|
Family ID: |
52389476 |
Appl. No.: |
14/341012 |
Filed: |
July 25, 2014 |
Current U.S.
Class: |
165/100 ;
165/148 |
Current CPC
Class: |
F28F 9/026 20130101;
F28F 9/001 20130101; Y02T 10/16 20130101; F02M 26/29 20160201; Y02T
10/12 20130101; F28D 21/0003 20130101; F28D 7/1684 20130101; F28F
27/02 20130101; F28F 9/02 20130101; F28D 2021/008 20130101 |
Class at
Publication: |
165/100 ;
165/148 |
International
Class: |
F28F 9/02 20060101
F28F009/02; F28F 27/02 20060101 F28F027/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 25, 2013 |
JP |
2013-154895 |
Claims
1. A heat exchanger comprising: a tubular core case; a pair of end
plates for closing opposite ends of the core case; and a plurality
of heat exchange tubes supported at opposite ends by the end plates
and allowing a first heating medium to flow inside thereof, so as
to effectuate heat exchange between the first heating medium and a
second heating medium flowing along an outer periphery of the heat
exchange tubes, wherein one of the end plates is disposed on an
upstream side of flow of the first heating medium as an upstream
end plate while another one of the end plates is disposed on a
downstream side of the flow of the first heating medium as a
downstream end plate, the downstream end plate comprises a
downstream bottom surface part for supporting downstream end parts
of the heat exchange tubes, and a downstream wall part formed
integrally with and rising from a peripheral edge of the downstream
bottom surface part, and a top end part of the downstream wall part
is oriented toward upstream of the flow of the first heating
medium.
2. The heat exchanger of claim 1, wherein the downstream wall part
is joined with the core case only at a top end side thereof.
3. The heat exchanger of claim 1, wherein the upstream end plate
comprises an upstream bottom surface part for supporting upstream
end parts of the heat exchange tubes, and an upstream wall part
formed integrally with and rising from a peripheral edge of the
upstream bottom surface part, and the top end part is oriented
toward downstream of the flow of the first heating medium.
4. The heat exchanger of claim 3, wherein the upstream wall part is
joined with the core case only at a top end side thereof.
5. The heat exchanger of claim 1, wherein the core case has a
second heating medium inlet for introducing the second heating
medium into the core case, and a guide part is provided in a
vicinity of the second heating medium inlet for guiding the second
heating medium toward the upstream side of the heat exchange
tubes.
6. The heat exchanger of claim 5, wherein the guide part comprises
a sheet-shaped guide plate joined with an inner peripheral surface
part of the core case and forming a closed cross section between
the guide plate and the inner peripheral surface part of the core
case, and the guide plate has a guide aperture formed at an
upstream-side end part thereof, through which aperture the second
heating medium is guided toward the upstream side of the heat
exchange tubes.
7. The heat exchanger of claim 5, wherein the guide part comprises
a sheet-shaped guide plate joined with an outer peripheral surface
part of the core case and defining a closed cross section between
the guide plate and the outer peripheral surface part of the core
case, and the core case has a guide aperture formed at an upstream
end part thereof, through which aperture the second heating medium
is guided toward the upstream side of the heat exchange tubes.
8. The heat exchanger of claim 6, wherein the guide aperture is
formed at a position corresponding to an inter-layer space of the
heat exchange tubes.
9. The heat exchanger of claim 1, wherein the core case has a
recessed part recessed inwardly along a direction of flow of the
first heating medium.
10. A heat exchange device comprising: a branching part for
allowing passage of an exhaust gas therethrough and branching the
exhaust gas into two streams; a first flow passage extending from
the branching part; a second flow passage extending from the
branching part along the first flow passage; a heat exchanger
disposed on the second flow passage for recovering energy from heat
of the exhaust gas; and a valve disposed openably/closably on one
of the first flow passage and the second flow passage for changing
a direction of flow of the exhaust gas, wherein the heat exchanger
comprises a heat exchanger defined in claim 1.
Description
FILED OF THE INVENTION
[0001] The present invention relates to a heat exchanger and a heat
exchange device employing the heat exchanger.
BACKGROUND OF THE INVENTION
[0002] Generally, a heat exchanger is designed to effect heat
exchange between a first heating medium that flows along an inner
periphery of a heat exchange tube and a second heating medium that
flows along an outer periphery of the heat exchange tube. It is
known to employ a heat exchanger in a heat exchange device (see JP
2012-184681 A, for example).
[0003] Referring to FIG. 13 hereof, explanation will be made as to
the heat exchange device disclosed in JP 2012-184681. As shown in
FIG. 13, an exhaust heat recovery apparatus 200, known also as a
heat exchange device, includes a heat recovery passage 202 in which
a heat exchanger 201 is housed for effecting heat exchange, and a
bypass 203 branched off from the heat recovery passage 202 and
where heat exchange is not performed.
[0004] The heat exchanger 201 is comprised of a core case 211, a
pair of end plates 212, 213 for closing respective ends of the core
case 211, and a plurality of heat exchange tubes 215 disposed
between the two end plates 212, 213 and allowing an exhaust gas to
flow inside thereof. Heat exchange is effected between the exhaust
gas that flows through the heat exchange tubes and a medium that
flows externally.
[0005] The exhaust heat recovery apparatus 200 employing the heat
exchanger 210 is generally mounted to an underside of a floor of a
vehicle body. Since a mounting space on the underside of the
vehicle body floor is small, it is desired that the exhaust heat
recovery apparatus 200 be compact and small. If the heat exchanger
210 is downsized, the exhaust heat recovery apparatus per se
becomes compact and small.
[0006] In addition, in a case in which the heat exchanger 210 is
employed in an apparatus other than the exhaust heat recovery
apparatus 200, if the heat exchanger 210 is downsized, this brings
the advantage that the apparatus in which the heat exchanger 210 is
employed can be positioned with increased freedom. There is
therefore a demand for downsizing of a heat exchanger.
SUMMARY OF THE INVENTION
[0007] According to a first aspect of the present invention, there
is provided a heat exchanger comprising: a tubular core case; a
pair of end plates for closing opposite ends of the core case; and
a plurality of heat exchange tubes supported at opposite ends by
the end plates and allowing a first heating medium to flow inside
thereof, so as to effectuate heat exchange between the first
heating medium and a second heating medium flowing along an outer
periphery of the heat exchange tubes, wherein one of the end plates
is disposed on an upstream side of flow of the first heating medium
as an upstream end plate while another one of the end plates is
disposed on a downstream side of the flow of the first heating
medium as a downstream end plate, the downstream end plate
comprises a downstream bottom surface part for supporting
downstream end parts of the heat exchange tubes, and a downstream
wall part formed integrally with and rising from a peripheral edge
of the downstream bottom surface part, and a top end part of the
downstream wall part is oriented toward upstream of the flow of the
first heating medium.
[0008] In the above-described inventive arrangement, the downstream
end plate is comprised of the downstream bottom surface part for
supporting the heat exchange tubes, and the downstream wall part
formed integrally with and rising from the peripheral edge of the
downstream bottom surface part, and the top end part of the
downstream wall part is disposed in orientation toward an upstream
side. Since the top end part of the downstream wall part is
oriented toward upstream, the top end part of the downstream wall
part is positioned further upstream than the downstream end parts
of the heat exchange tubes, whereby the heat exchanger is
downsized.
[0009] Preferably, the downstream wall part is joined with the core
case only at a top end side thereof.
[0010] It is preferred that the upstream end plate comprise an
upstream bottom surface part for supporting upstream end parts of
the heat exchange tubes, and an upstream wall part formed
integrally with and rising from a peripheral edge of the upstream
bottom surface part, and the top end part be oriented toward
downstream of the flow of the first heating medium.
[0011] Desirably, the upstream wall part is joined with the core
case only at a top end side thereof.
[0012] It is preferred that the core case have a second heating
medium inlet for introducing the second heating medium into the
core case, and a guide part be provided in the vicinity of the
second heating medium inlet for guiding the second heating medium
toward the upstream side of the heat exchange tubes.
[0013] In a preferred form, the guide part comprises a sheet-shaped
guide plate joined with an inner peripheral surface part of the
core case and forming a closed cross section between the guide
plate and the inner peripheral surface part of the core case, while
the guide plate has a guide aperture formed at an upstream-side end
part thereof, through which aperture the second heating medium is
guided toward the upstream side of the heat exchange tubes.
[0014] It is preferred that the guide part comprise a sheet-shaped
guide plate joined with an outer peripheral surface part of the
core case and defining a closed cross section between the guide
plate and the outer peripheral surface part of the core case, and
the core case have a guide aperture formed at an upstream end part
thereof, through which aperture the second heating medium is guided
toward the upstream side of the heat exchange tubes.
[0015] Desirably, the guide aperture is formed at a position
corresponding to an inter-layer space of the heat exchange
tubes.
[0016] In a desired form, the core case has a recessed part
recessed inwardly along a direction of flow of the first heating
medium.
[0017] According to a second aspect of the present invention, there
is provided a heat exchange device which comprises: a branching
part for allowing passage of an exhaust gas therethrough and
branching the exhaust gas into two streams; a first flow passage
extending from the branching part; a second flow passage extending
from the branching part along the first flow passage; a heat
exchanger disposed on the second flow passage for recovering energy
from heat of the exhaust gas; and a valve disposed
openably/closably on one of the first flow passage and the second
flow passage for changing a direction of flow of the exhaust gas,
wherein the heat exchanger comprises a heat exchanger according to
the first aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Certain preferred embodiments of the present invention will
be described in detail below, by way of example only, with
reference to the accompanying drawings, in which:
[0019] FIG. 1 is a top plan view illustrating an exhaust heat
recovery apparatus employing a heat exchanger according to a first
embodiment of the present invention:
[0020] FIG. 2 is a cross-sectional view taken along line 2-2 of
FIG. 1;
[0021] FIG. 3 is a perspective view illustrating the heat exchanger
of FIG. 2;
[0022] FIG. 4 is an exploded perspective view illustrating a lower
case half and a guide plate;
[0023] FIG. 5 is a perspective view illustrating the lower case
half and the guide plate joined together;
[0024] FIG. 6 is a schematic view illustrating an operation of the
heat exchanger of FIG. 2;
[0025] FIG. 7 is a cross-sectional view illustrating a heat
exchanger according to a second embodiment of the present
invention;
[0026] FIG. 8 is a perspective view illustrating the heat exchanger
of FIG. 7;
[0027] FIG. 9 is a cross-sectional view taken along line 9-9 of
FIG. 7;
[0028] FIG. 10 is an exploded perspective view illustrating a lower
case half and a guide plate according to the second embodiment of
the present invention;
[0029] FIG. 11 is a perspective view illustrating the lower case
half and the guide plate, joined together, of FIG. 10;
[0030] FIG. 12 is a cross-sectional view illustrating a heat
exchanger according to a third embodiment of the present invention;
and
[0031] FIG. 13 is a cross-sectional view illustrating a
conventional, basic arrangement.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1
[0032] Reference is made initially to FIG. 1. As shown in FIG. 1,
an exhaust heat recovery apparatus 10 (heat exchange device)
includes an exhaust gas inlet 11 for introducing exhaust gas (first
heating medium) generated in an internal combustion engine (not
shown), a branching part 12 connected to the inlet 11, a first flow
passage 13 connected to the branching part 12 and extending
downstream of the inlet 11, a second flow passage 14 extending from
the branching part 12 along the first flow passage 13, a heat
exchanger 30 forming part of the second flow passage 14 for
transmitting heat of the exhaust gas to a medium (second heating
medium), a thermoactuator 16 connected to the heat exchanger 30, a
valve chamber 17 to which the first and second flow passages 13, 14
are connected at downstream ends thereof, a discharge outlet 18
connected to the valve chamber 17 for discharging the exhaust gas,
and a valve housed in the valve chamber 17 and adapted to close the
first flow passage 13 or the second flow passages 14. The valve
chamber 17 serves also as a merging part where streams of the
exhaust gas passed through the first and second flow passages merge
or meet.
[0033] In the state shown in the Figure, the valve 19 closes the
first flow passage 13. At this time, the second flow passage 14 is
opened to allow the exhaust gas to pass therethrough. On the other
hand, when the valve 19 swings on a certain condition, the valve 19
closes the second flow passage 14, whereupon the first flow passage
13 is opened to allow passage of the exhaust gas therethrough.
[0034] A medium introducing pipe 21 (second heating medium
introducing pipe) is connected to a side of the heat exchanger 30
for introducing heating medium. An actuator support member 22 is
connected to the heat exchanger 30 for supporting the
thermoactuator 16. A medium discharge pipe 23 (second heating
medium discharge pipe) is connected to the actuator support member
22 for discharging the heating medium.
[0035] Namely, the medium is introduced into the heat exchanger 30
through the medium introducing pipe 21. The thus-introduced medium
receives heat from the exhausted gas within the heat exchanger 30
and discharged through the medium discharge pipe 23. That is, the
heat exchanger 30 recovers energy of the exhaust gas. Detailed
discussion as to the heat exchanger 30 will be made with reference
to Figures that follow.
[0036] As shown in FIG. 2, the heat exchanger 30 is comprised of a
generally square-tube-shaped core case 31 adapted to allow flow of
the medium internally, upstream and downstream end plates 32, 33
mounted so as to close openings at opposite ends of the core case
31, a heat exchange tube 34 mounted between the upstream and
downstream end plates 32, 33 and adapted to allow passage of the
exhaust gas internally, and a fin 35 housed in the heat exchange
tube 34.
[0037] Turning now to FIG. 3, the upstream end plate 32 includes a
plurality of heat exchange tubes 34 inserted thereinto. The
downstream end plate 33 is similarly configured.
[0038] The core case 31 is comprised of a lower case half 41 having
a generally U-shape as viewed in front elevation and forming a
lower half of the core case 31, and an upper case half joined with
the lower case half 41 to form an upper part of the core case 31.
The upper case half 42 is also generally U shaped as view in front
elevation.
[0039] The lower case half 41 has a side surface portion 41a which
is provided with a medium inlet 41b (second heating medium inlet)
for introducing medium. The medium introducing pipe 21 (FIG. 1) is
connected to the medium inlet 41b.
[0040] The upper case half 42 is comprised of a connecting part 42a
connected to the upstream end plate 32, the downstream end plate 33
and the lower case half 41, and a recessed part 42b recessed
inwardly from the connecting part 42a. On an upper surface part 42c
of the recessed part 42b, a medium discharge outlet 42d (second
heating medium discharge outlet) is provided for discharging the
medium. The actuator support member 22 is connected to the medium
discharge outlet 42d.
[0041] Turning back to FIG. 2, the upstream end plate 32 includes a
generally rectangular-shaped upstream bottom surface part 32a for
supporting an upstream end part 34a of the heat exchange tube 34,
and an upstream wall part 32b formed integrally with and rising
from a peripheral edge of the upstream bottom surface part 32a. The
upstream wall part 32b extends toward downstream from the upstream
bottom surface part 32a. Top end part 32c of the upstream wall part
32b is located at a downstream-most position.
[0042] The upstream bottom surface part 32a has a plurality of
support holes 32d for allowing passage of and supporting the heat
exchange tube 34. Of the upstream wall part 32b, only the top end
32c is joined with the core case 31.
[0043] The downstream end plate 33 is configured similarly. Namely,
the downstream end plate 33 is comprised of a downstream bottom
surface part 33a having a generally rectangular shape and
supporting a downstream end part 34b of the heat exchange tube 34,
and a downstream wall part 33b formed integrally with and rising
from a peripheral edge of the downstream bottom surface part 33a.
The downstream wall part 33b extends from the downstream bottom
surface part 33a toward upstream. Top end part 33c of the
downstream wall part 33b is located at an upstream-most
position.
[0044] The downstream bottom surface part 33a has a plurality of
support holes 33d for allowing passage of and supporting the heat
exchange tube 34. Of the downstream wall part 33b, only the top end
part 33c is connected to the core case 31.
[0045] The core case 31 has a recessed part 42b recessed inwardly
along the direction of flow of the exhaust gas. Provision of the
recessed part 42b imparts increased rigidity to the core case 31.
This makes it possible to increase rigidity against the direction
of expansion of the medium and hence to impart a prolonged life to
the heat exchanger 10.
[0046] Of the upstream wall part 32b, only the top end part 32c is
connected to the core case 31. Thus, the peripheral edge of the
upstream wall part 32b is not joined with the core case 31. As a
result, a member for introducing exhaust gas can be connected
directly to the peripheral edge of the upstream wall part 32b.
Since direct connection of the heat exchanger 10 with the
associated flow passage becomes possible, an additional part for
connecting the heat exchange with the associated flow passage will
not be required. This leads to the advantage that the number of
required parts may be decreased. The same can be said of the
downstream end plate 33.
[0047] At a lower part of the core case 31, there is provided a
guide part 37 for guiding the medium toward upstream of the heat
exchange tube 34. The guide part 37 is comprised of a guide plate
50 which is connected to an inner peripheral surface part 31a of
the core case 31 in such a manner as to form a closed cross section
between the guide plate 50 and the inner peripheral surface part
31a.
[0048] The upstream wall part 32b of the upstream end plate 32 and
the downstream wall part 33b of the downstream end plate 33
desirably have a length in the range of 10 mm to 24 mm. The
upstream and downstream wall parts 32b, 33b are overlapped with
respective upstream and downstream parts in an overlap range of 2
mm to 7 mm. Ranges left between the overlap ranges are 6 mm to 10
mm. The portions between the overlap ranges are set to have a
length that will not allow them to overlap with their respective
weld beads.
[0049] As shown in FIG. 4, the guide plate 50 is obtained by
press-forming a steel sheet into a generally L shape. More
specifically, the guide plate 50 is comprised of an introducing
part 51 provided at a position corresponding to the medium inlet
41b so as to cover the medium inlet 41b, a guide-forming part 52
extending from a lower end of the introducing part 51 laterally of
the core case 31, and a flange part 53 integrally provided at a
peripheral edge of the introducing inlet 51 and the guide-forming
part 52 and adapted to be joined with the inner peripheral surface
part 31a of the core case 31.
[0050] The introducing part 51 bulging from the flange part 53
defines, jointly with the guide-forming part 52, a closed
cross-section between the inner peripheral surface part 31a and the
guide-forming part 52. At an upstream end part, the guide-forming
part 52 has a plurality of guide apertures 52a, 52a for guiding the
medium toward upstream of the heat exchange tube 34 (FIG. 2).
[0051] In the state in which the guide plate 50 is attached to the
lower case half 41, as shown in FIG. 5, the medium introduced
through the medium inlet 41b, as shown by arrow (1), is guided into
the inside of the core case 31 by the guide-forming part 52. The
medium thus guided into the core case 31 is caused to flow through
the guide apertures 52a, 52a toward upstream of the core case 31,
as shown by arrows (2), (2).
[0052] Turning back to FIG. 2, the introduced medium flows first
through the core case 31 toward upstream. Flowing through the
upstream is the exhaust gas that is yet to be heat-exchanged.
Efficient heat exchange is enabled by effectuating heat exchange
between a non-heat-exchanged, high-temperature exhaust gas and a
non-heat-exchanged, low-temperature medium.
[0053] By causing the medium to flow upstream, it becomes possible
to suppress an increase in stress that arises by excessive heating
of the upstream end plate 32. This makes it possible to reduce a
load applied to the heat exchanger 30 and hence to prolong the life
of the heat exchanger 30. The medium may boil by heating it to a
high temperature. By making the medium flow upstream, it becomes
possible to stably supply the medium upstream and hence to avoid
boiling of the medium. As a result, improved heat exchange
efficiency is provided.
[0054] Note also that the guide part is formed of the guide plate
50 of sheet shape that defines a closed cross section between the
plate 50 and the core case 31 and that the upstream end part of the
guide plate 50 is provided with the guide apertures 52a. By this
simple arrangement, it becomes possible to make the medium flow
upstream of the heat exchange tube 34.
[0055] As shown in (a) of FIG. 6, a heat exchanger 230, a known
example for comparison, includes an upstream end plate 232 with an
upstream wall part 232b extending from an upstream bottom surface
part 232a toward upstream. A downstream end plate 233 includes a
downstream wall part 233b extending from a downstream bottom
surface part 233a toward downstream.
[0056] When the upstream wall part 232b is oriented toward upstream
(leftward), a top end part 232c of the upstream wall part 232b
projects forward from the upstream end part 34a of the heat
exchange tube 34 thereby increasing the overall length of the heat
exchanger 230.
[0057] The same discussion is applicable to the downstream end
plate 233.
[0058] Namely, when the downstream wall part 233b is oriented
toward downstream, a top end part 233c of the downstream wall part
233b projects rearward from the downstream end part 34b of the heat
exchange tube 34 thereby increasing the overall length of the heat
exchanger 230.
[0059] Reference is now made to FIG. 6(b) illustrating the heat
exchanger 30 according to the inventive embodiment. As shown in the
Figure, the upstream end plate 32 is comprised of the upstream
bottom surface part 32a supporting the heat exchange tube 34, and
the upstream wall part 34a formed integrally with and rising from
the peripheral edge of the upstream bottom surface part 32a. The
top end part 32c of the upstream wall part 32b is connected to the
core case 31.
[0060] Since the top end part 32c of the upstream wall part 32b is
oriented toward downstream, the top end part 32c of the upstream
wall part 32b is positioned nearer to downstream than the upstream
end part 34a of the heat exchange tube 34. As a result, the overall
length of the heat exchanger 30 becomes smaller (see .alpha.),
whereby the heat exchanger 30 is downsized.
[0061] Note also that the top end part 32c of the upstream wall
part 32b extends rearward from the upstream end part 34a of the
heat exchange tube 34 and is connected to the core case 31. As a
result, the core case 31 is made shorter by the length of the
upstream wall part 32b and hence downsized.
[0062] In the arrangement explained above, it is possible to make
the medium flow through an area enclosed by the upstream wall part
32b and the upstream bottom surface part 32a. The core case 31 is
downsized an amount equivalent to the area and hence the heat
exchanger 30 per se is downsized.
[0063] The same discussion is applied to the downstream end plate
33. Since the top end part 33c of the downstream wall part 33b is
oriented toward upstream, the top end part 33c of the downstream
wall part 33b is positioned nearer to upstream than the downstream
end part 34b of the heat exchange tube 34. As a result, the overall
length of the heat exchanger 30 is decreased (see .beta.) to
thereby downsize the heat exchanger 30.
[0064] Note additionally that the top end part 33c of the
downstream wall part 33b extends forward from the downstream end
part 34b of the heat exchange tube 34 and is joined with the core
case 31. The core case 31 is decreased in length by the length of
the downstream wall part 33b, whereby the core case 31 is
downsized.
[0065] Note further that in the arrangement explained above, it is
possible to make the medium flow through an area enclosed by the
downstream wall part 33b and the downstream bottom surface part
33a. This makes it possible to downsize the core case 31 by the
amount equivalent to the area and hence the heat exchanger 30 as a
whole.
[0066] As compared with the known example heat exchanger 230 (FIG.
6(a)), the upstream side of the inventive heat exchanger 30 became
shorter by .alpha.. The same discussion is applicable to the
downstream end plate 33. Compared to the know example heat
exchanger 230, the inventive core case 30 became shorter in the
downstream side by .beta.. To sum up, the heat exchanger 30 of the
inventive embodiment is made shorter by .alpha.+.beta..
[0067] Referring also to FIG. 1, it will readily be appreciated
that by employing the heat exchanger 30 rendered compact as
explained above, the exhaust heat recovery apparatus 10 per se is
made compact. It is desirable that freedom of positioning of the
exhaust heat recovery apparatus 10 be increased.
Embodiment 2
[0068] Discussion will be made next as to a second embodiment of
the present invention with reference to FIGS. 6-11.
[0069] FIG. 7 illustrates in cross-section a heat exchanger
according to a second embodiment of the present invention in
correspondence with FIG. 2. The heat exchanger according to the
second embodiment differs from the heat exchanger shown in FIG. 2
in that the core case and the guide part are constructed
differently.
[0070] As shown in FIGS. 7 and 8, the heat exchanger 60 has a core
case 61 which is comprised of a lower case half 71 having a
generally U shape as seen in front elevation, an upper case half 72
having a generally U shape as seen in front elevation and coupled
with the lower case half 71 from above, and a guide plate joined
with a side surface and a bottom surface of the lower case half 71
from outside.
[0071] The lower case half 71 is comprised of joining parts 71a,
71a joined with the upstream end plate 32 and the downstream end
plate 33, and a recessed part 71b provided between the joining
parts 71a, 71a and recessed inwardly. The recessed part 71b is
comprised of tapered parts 71c, 71c extending inclinedly from end
parts of the joining parts 71a, 71a, and a planar part 71d
extending between the tapered parts 71a, 71c and parallel to the
heat exchange tube 34.
[0072] The guide plate 80 is comprised of an inlet part 81 joined
at a position corresponding to a side surface of the lower case
half 71, a guide forming part 82 extending from a lower end of the
inlet part 81 in a direction of width of the core case 61, and a
flange part 83 formed integrally with peripheral edges of the inlet
part 81 and the guide forming part 82 and joined with an outer
peripheral surface part 61b of the core case 61.
[0073] The inlet part 81 is provided with a medium inlet (second
heating medium inlet) 81a for introducing the heating medium. The
medium introducing pipe 21 is connected to the medium inlet
81a.
[0074] The inlet part 81 and the guide forming part 82 jointly
define a closed cross section between them and an outer peripheral
surface part 61b of the core case 61 to thereby provide a guide
part 67. The upstream tapered part 71c is formed with a guide
aperture 71e for guiding the medium toward the upstream of the heat
exchange tube 34. In addition, a plurality of small apertures 71f,
smaller than the guide aperture 71e, is formed in the planar part
71d.
[0075] As shown in FIG. 9, the guide aperture 71e and the small
apertures 71f are formed at locations between corresponding layers
of the heat exchange tube 34. It becomes possible to make the
medium flow toward the interlayer space. By thus making the medium
flow directly to locations where flow passage areas are large, the
medium flows smoothly. As a result, heat exchange can be effected
efficiently.
[0076] Referring now to FIG. 10, the recessed part 71b is formed to
run all around the lower case half 71. The guide part 67 is
constructed by covering the thus-formed outer peripheral surface
part 61b of the lower case half 71 with the guide plate 80.
[0077] As can be appreciated from FIG. 11, the guide aperture 71e
has a size larger than those of the small apertures 71f. Thus, the
medium fed in through the medium inlet 81a, as shown by arrow (5),
flows on toward upstream chiefly through the guide aperture 71e, as
shown by arrow (6). On the other hand, a remaining portion of the
medium is introduced into the core case 61 through the small
apertures 71f, as shown by arrow (7). The medium is introduce into
the core case 61 through the guide aperture 71e as a major stream
and through the small apertures 71f. As a result, it becomes
possible for the medium to flow into the core case 61 in larger
quantity, thereby enabling efficient heat exchange.
Embodiment 3
[0078] Explanation will be made next as to a third embodiment of
the present invention with reference to FIG. 12 wherein the
construction of a heat exchanger according to the third embodiment
is shown in cross section in correspondence with the arrangement of
FIG. 2.
[0079] As shown in FIG. 12, a heat exchanger 90 includes an
upstream end plate 92 which is comprised of an end plate body 101
connected to the core case 31 and having a generally U shape as
viewed in cross section, and a support plate 102 connected to the
end plate body 101 and supporting the heat exchange tube 34.
[0080] The end plate body 101 is comprised of an upstream bottom
surface part 101a and an upstream wall part 101b formed integrally
with and rising from a peripheral edge of the upstream bottom
surface part 101a. A rectangular aperture 101c is formed in the
upstream bottom surface part 101a. The support plate 102 is joined
with the peripheral edge of the rectangular aperture 101c. The
support plate 102 has a thickness smaller than that of the end
plate 101.
[0081] The same discussion is applied to the downstream end plate
93. The downstream end plate 93 is comprised of an end plate body
106 joined with core case 31 and having a generally U shape as
viewed in cross section, and a support plate 107 connected to the
end plate body 106 for supporting the heat exchange tube 34.
[0082] The end plate body 106 is comprised of a downstream bottom
surface part 106a and a downstream wall part 106b formed integrally
with and rising from the peripheral edge of the downstream bottom
surface part 106a. A rectangular aperture 106c is formed in the
downstream bottom surface part 106a. A support plate 107 is
connected to the peripheral edge of the rectangular aperture 106c.
The support plate 107 has a thickness smaller than that of the end
plate body 106.
[0083] The upstream end plate 92 and the downstream end plate 93
are positioned differently in orientation. In the upstream end
plate 92, the upstream wall part 101b is extends from the upstream
wall part 101a toward upstream. As a result, a top end part 101d of
the upstream wall part 101b extends in a direction away from the
core case 31. On the other hand, in the downstream end plate 93,
the downstream wall part 106b extends from the downstream bottom
surface part 106a toward upstream. As a result, a top end part 106d
of the downstream wall part 106b extends toward the core case
31.
[0084] Even when the top end part 106d of the downstream wall part
106b is oriented toward upstream while the top end part 101d of the
upstream wall part 101b is not oriented toward downstream as above,
advantageous effects aimed at by the present invention can be
achieved. In other words, to an extent in which the top end part
106d of the downstream wall part 106b is oriented toward upstream,
the core case 31 can be downsized (see .beta. of FIG. 6). This
further leads to downsizing of the heat exchanger 90.
[0085] Hot exhaust gas flows through the heat exchange tube 34 and
the heat of the gas causes the tube 34 to stretch. Since the
thickness of the support plate 102 is smaller than the thickness of
the end plate body 101, the support plate 102 has smaller flexural
rigidity than the end plate body 101. Thus, compared to the end
plate body 101, the support plate 102 is liable to bend. Since the
heat exchange tube 34 is inserted to a portion liable to bend,
stretch of the heat exchange tube 34 can be absorbed by flexure or
bend. This makes it possible to reduce a load applied to the heat
exchange tube 34 and hence to prolong the life of the heat
exchanger 90. The same goes to the downstream end plate 93.
[0086] It should also be appreciated that even when both the
upstream end plate 92 and the downstream end plate 93 are
oppositely oriented, the advantageous effects of the invention can
be produced (see .alpha. of FIG. 6). Namely, it is possible that
the top end part 101d of the upstream end plate 92 be joined with
the core case 31 while the top end part 106d of the downstream end
plate 93 be disposed to extend away from the core case 31 toward
downstream.
[0087] Although the heat exchanger of the present invention has
thus far been described as being applied to an exhaust heat
recovery apparatus, it may readily be applied to an EGR (Exhaust
Gas Recirculation) air conditioner, a cogeneration system and a
thermoelectric generation system. It may also be applied to other
systems than those as above in which heat exchange is carried out
between an exhaust gas and a medium.
[0088] It can also be appreciated by a person skilled in the art
that part of the heat exchange according to the third embodiment
can be applied to the heat exchanger according to the first
embodiment. Namely, the embodiments can be combined with one
another as necessary.
[0089] Obviously, various minor changes are possible in light of
the above teaching. It is therefore to be understood that within
the scope of the appended claims the invention may be practiced
otherwise than as specifically described above.
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