U.S. patent application number 11/203153 was filed with the patent office on 2005-12-08 for heat exchanger.
This patent application is currently assigned to SHOWA DENKO K.K.. Invention is credited to Horiuchi, Hirofumi, Hoshino, Ryoichi, Ogasawara, Noboru, Tamura, Takashi, Terada, Takashi, Watanabe, Futoshi.
Application Number | 20050269066 11/203153 |
Document ID | / |
Family ID | 26609606 |
Filed Date | 2005-12-08 |
United States Patent
Application |
20050269066 |
Kind Code |
A1 |
Horiuchi, Hirofumi ; et
al. |
December 8, 2005 |
Heat exchanger
Abstract
The invention relates to heat exchangers for use in motor
vehicles or for industrial use, for example, to heat exchangers for
use as evaporators, condensers, oil coolers, intercoolers, heater
cores, etc. The invention provides a heat exchanger comprising
pairs of plates with each plate of the pair having formed on one
side thereof a peripheral ridge, central ridge and channel dividing
U-shaped ridges which are formed by forging or cutting. Each pair
of plates are fitted together and joined, with channel recesses
thereof opposed to each other to form a flat tube and a plurality
of U-shaped divided fluid passageways in a U-shaped fluid channel
inside the tube. Each pair of adjacent flat tubes are joined by
spectacle-shaped header members interposed between the upper ends
of the tubes and each comprising a front and a rear fluid passing
tube portion and a connecting portion therebetween to provide a
front and a rear header in communication with the upper ends of the
flat tubes. The flat tubes have a reduced front-to-rear width,
diminished wall thickness (thinner layers) and increased heat
transfer efficiency to provide a heat exchanger which achieves a
higher heat transfer efficiency and greatly improved heat exchange
performance.
Inventors: |
Horiuchi, Hirofumi;
(Oyama-shi, JP) ; Hoshino, Ryoichi; (Oyama-shi,
JP) ; Ogasawara, Noboru; (Oyama-shi, JP) ;
Tamura, Takashi; (Oyama-shi, JP) ; Terada,
Takashi; (Oyama-shi, JP) ; Watanabe, Futoshi;
(Oyama-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SHOWA DENKO K.K.
Minato-ku
JP
|
Family ID: |
26609606 |
Appl. No.: |
11/203153 |
Filed: |
August 15, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11203153 |
Aug 15, 2005 |
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10467066 |
Aug 19, 2003 |
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10467066 |
Aug 19, 2003 |
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PCT/JP02/01343 |
Feb 18, 2002 |
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60302371 |
Jul 3, 2001 |
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Current U.S.
Class: |
165/153 |
Current CPC
Class: |
Y02P 80/10 20151101;
F28D 1/035 20130101; F28D 1/0333 20130101; F28D 1/0375 20130101;
F28F 1/022 20130101 |
Class at
Publication: |
165/153 |
International
Class: |
F28D 001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 19, 2001 |
JP |
2001-41449 |
Claims
1. A heat exchanger comprising ridged plates each having a
peripheral ridge provided on one side of the plate along a
periphery thereof and a central ridge provided on said one side of
the plate at a center of the width thereof and extending downward
from an upper end of the plate to a position where a return channel
can be formed, the ridges being formed by forging, each of the
ridged plates having a U-shaped channel recess formed inwardly of
the peripheral ridge and comprising a front and a rear channel
recess portion formed on opposite sides of the central ridge and a
return channel recess portion positioned under the central ridge,
the channel recess having one of two fluid inlet-outlet through
holes formed at one end thereof and the other through hole formed
at the other end thereof, each of the ridged plates having a flat
surface on the other side thereof and being fitted to each of flat
plates face-to-face, each of said flat plates having the same
contour and the same size as the ridged plate and two fluid
inlet-outlet through holes corresponding to said through holes, the
peripheral ridge of the ridged plate having a top end thereof
joined to a peripheral edge of the flat plate, the central ridge of
the ridged plate having a top end thereof joined to a flat surface
of a corresponding central portion of the flat plate, whereby a
flat tube having a U-shaped fluid channel inside thereof is formed
so that a plurality of flat tubes are arranged in parallel with a
header member interposed between upper ends of each pair of
adjacent flat tubes to provide a front and a rear header in
communication with the upper ends of the said pair of adjacent flat
tubes, the header member comprising a pair of front and rear fluid
passing tube portions in communications with the respective
inlet-outlet through holes of the plates of said pair of adjacent
flat tubes and a connecting portion between the tube portions.
2. A heat exchanger according to claim 1, wherein a plurality of
channel dividing U-shaped ridges are formed in the U-shaped channel
recess of each ridged plate by forging, and each ridged plate and
each flat plate are fitted together face-to-face with the channel
dividing U-shaped ridges of the ridged plate joined to the flat
surface of the corresponding central portion of the flat plate to
form a plurality of U-shaped divided fluid passageways in the
U-shaped fluid channel inside the flat tube.
3. A heat exchanger according to claim 1, wherein the header member
interposed between the ends of each pair of adjacent flat tubes has
its fluid passing tube portions joined at their opposite end faces
to the flat surfaces on the other sides of the opposed plates of
the pair of flat tubes.
4. A heat exchanger according to claim 1, wherein tacks for
temporarily holding the header member are provided respective edges
defining the inlet-outlet through holes in the end of each
plate.
5. A heat exchanger according to claim 2, wherein a plurality of
cutouts are formed in the channel dividing ridges on each plate to
cause the adjacent divided fluid passageways inside the flat tube
to communicate with each other through the cutouts.
6. A heat exchanger according to claim 1, wherein a fin is provided
between each pair of adjacent flat tubes included in the flat tubes
arranged in parallel, and the fin has opposite sides edges thereof
joined to the flat surfaces on the other sides of the plates of the
pair of flat tubes.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is an application filed under 35 U.S.C.
111(a) claiming the benefit pursuant to 35 U.S.C. 119(e)(1) of the
filing data of Provisional Application No. 60/302,371 filed Jul. 3,
2001 pursuant to 35 U.S.C. 111(b).
TECHNICAL FIELD
[0002] The present invention relates to heat exchangers for use in
motor vehicles or for industrial use, for example, to heat
exchangers for use as evaporators, condensers, oil coolers,
intercoolers, heater cores, etc.
[0003] Generally aluminum heat exchangers are conventionally in
wide use as heat exchangers, especially as evaporators for motor
vehicle air conditioners, from the viewpoint of lightweightness and
workabiliy.
[0004] At present, evaporators for motor vehicle air conditioners
are chiefly those of the laminate type (layered type). In
fabricating evaporators of this type, heat exchange fins for air
and a tube portion for evaporating the refrigerant are joined
together by brazing, so that such evaporators are superior to heat
exchangers of the fin tube enlarged type which were previously in
use, for example, with respect to performance and productivity.
These evaporators are exceedingly superior to the fin tube enlarged
type especially in performance characteristics since louver fins of
high heat transfer efficiency are usable as air fins for this type
of evaporators to ensure an increased quantity of heat exchange and
low resistance to the flow of air.
[0005] Accordingly, more lightweight and compact heat exchangers
are made available to meet the market demand for smaller sizes and
reduced weight. Especially recently, many evaporators are provided
with a filter on the front side in view of problems involved in the
vehicle compartment, and it has been strongly required that heat
exchangers be reduced in thickness to provide space for the
installation of the filter.
[0006] For example as shown in FIG. 25, conventional heat
exchangers for use as evaporators comprise generally rectangular
aluminum plates 62 each having formed in one surface thereof front
and rear refrigerant channel forming recessed porions 66 divided by
a vertically elongated partition ridge 64, and header forming
recessed portions (not shown) respectively continuous with the
upper and lower ends of these recessed portions 66 and having a
larger depth than these portions 66. Each pair of adjacent plates
62 are fitted together in superposed layers with their recessed
surfaces opposed to each other to join the opposed partition ridges
64, 64 of the plates 62, 62 to each other and opposed peripheral
edges 63, 63 thereof to each other and to thereby form a flat tube
portion 61 having front and rear flat refrigerant channels 68 and
upper and lower header portions continuous with the respective
channels 68. A multiplicity of such flat tube portions 61 are
arranged in parallel with a fin interposed therebetween for air to
provide the heat exchanger. Each of the plates 62 is prepared from
an aluminum sheet by press forming.
[0007] The conventional heat exchanger for use as an evaporator
encounters the following problems in fulfilling the commercial
demand for a reduced thickness.
[0008] (1) The plates 62 for forming the flat tube portion 61 are
made from an aluminum sheet by drawing with use of a press, so that
the partition ridge 64 and the peripheral edge 63 have an increased
width. Accordingly, the joints between the two plates 62, 62, i.e.,
the joint of the opposed partition ridges of the plates 62, 62 and
the joint of the opposed peripheral edges 63, 63 which are useless
portions not passing the refrigerant have a relatively great area,
which consequently reduces the cross sectional area of the
refrigerant channel when the evaporator has a given volume,
offering increased resistance to the flow of the refrigerant and
resulting in impaired performance.
[0009] To meet this problem, it appears useful to give an increased
height to the refrigerant channel and thereby assure the channel of
a sufficient cross sectional area, whereas the volume to be
occupied by the air-side fin in the given volume will then
decrease. Thus, the fin has a smaller area for heat transfer and is
impaired in performance, while a diminished air passage produces
increased resistance to the flow of air, failing to afford a proper
rate of air flow.
[0010] (2) On the other hand, the joint between the peripheral
edges 63, 63 of the two plates 62, 62 is out of direct contact with
the fin for the air side to exhibit a low heat transfer efficiency,
so that a reduction in the thickness of the heat exchanger
including such useless portions increases the relative ratio in
area of the useless portions not participating in the passage of
the refrigerant.
[0011] (3) The header forming recessed portions of the plate 62 are
given a greater depth than the front and rear refrigerant channel
forming recessed portions 66, 66 on opposite sides of the partition
ridge 64 by being worked by drawing, and are therefore made smaller
in wall thickness than the recessed portions 66. Although the flat
tube portion 61 having a great proportion is given an allowance for
pressure resistance, the header portions are weakest against
pressure. With the conventional heat exchanger, the flat tube
portion 61 and the header portions are made from an integral plate
material, and that by press work, so that there are limitations in
further reducing the header portions in wall thickness and
weight.
[0012] An object of the present invention is to overcome the
foregoing technical problems of the prior art and to provide a heat
exchanger which is fabricated from plates having ridges and
recessed portions formed in one surface thereof as by forging or
cutting work instead of using plates formed by press work and in
which headers are formed from a member separate from the plate to
make a flat tube having a reduced front-to-rear width, a diminished
wall thickness (layer of diminished thickness) and an increased
heat transfer area, the heat exchanger thus being adapted to
achieve a higher heat transfer efficiency and greatly improved heat
exchange performance.
DISCLOSURE OF THE INVENTION
[0013] First, the present invention provides a heat exchanger which
is characterized in that the heat exchanger comprises pairs of
plates with each plate of the pairs having a peripheral ridge
provided on one side of the plate along a periphery thereof and a
central ridge provided on said one side of the plate at a center of
the width thereof and extending downward from an upper end of the
plate to a position where a return channel can be formed, the
ridges being formed by forging or cutting, each plate of said pairs
having a U-shaped channel recess formed inwardly of the peripheral
ridge and comprising a front and a rear channel recess portion
formed on opposite sides of the central ridge and a return channel
recess portion positioned under the central ridge, the channel
recess having one of two fluid inlet-outlet through holes formed at
one end thereof and the other through hole formed at the other end
thereof, each plate of said pairs having a flat surface on the
other side thereof, each of said pairs of plates being fitted
together with their U-shaped channel recesses opposed to each other
to join the opposed peripheral ridges to each other end-to-end and
the opposed central ridges to each other end-to-end and to thereby
form a flat tube having a U-shaped fluid channel inside thereof so
that a plurality of flat tubes are arranged in parallel with a
header member interposed between upper ends of each pair of
adjacent flat tubes to provide a front and a rear header in
communication with the upper ends of the said pair of adjacent flat
tubes, the header member comprising a pair of front and rear fluid
passing tube portions in communications with the respective
inlet-outlet through holes of the plates of said pair of adjacent
flat tubes and a connecting portion between the tube portions.
[0014] Second, the present invention provides a heat exchanger
which is characterized in that the heat exchanger comprises pairs
of plates with each plate of the pairs having an edge ridge
U-shaped in its entirety and provided on one side of the plate
along opposite side edges and a lower edge thereof and a central
ridge provided on said one side of the plate at a center of the
width thereof and having a bifurcated upper end, the central ridge
extending from the upper end downward to a position where a return
channel can be formed, the ridges being formed by forging or
cutting, each plate of said pairs having a U-shaped channel recess
formed inwardly of the U-shaped edge ridge and comprising a front
and a rear channel recess portion formed on opposite sides of the
central ridge and a return channel recess portion positioned under
the central ridge, each plate of said pairs having a flat surface
on the other side thereof, each of said pairs of plates being
fitted together with their U-shaped channel recesses opposed to
each other to join the opposed U-shaped edge ridges to each other
end-to-end and the opposed central ridges including the bifurcated
upper ends to each other end-to-end and to thereby form a flat tube
having bifurcated open upper ends and a U-shaped fluid channel
inside thereof, a pair of front and rear header members being each
in the form of a pipe having a rectangular cross section, each of
the header members having slits formed in a lower wall thereof and
arranged at a predetermined spacing, a plurality of flat tubes
being arranged in parallel by inserting the bifurcated open upper
ends thereof into the respective slits in the front and rear header
members to join the flat tubes to the header members and to provide
a front and a rear header in communication with the bifurcated open
upper ends of the flat tubes.
[0015] With the heat exchanger having the first or second feature
described, a plurality of channel dividing U-shaped ridges are
formed in the U-shaped channel recess of each plate by forging or
cutting, and a pluralty of U-shaped divided fluid passageways are
formed in the U-shaped fluid channel in the interior of each flat
tube. The invention provides several modes of channel dividing
ridges.
[0016] As a first mode, a plurality of channel dividing U-shaped
ridges are formed in the U-shaped channel recess of each plate by
forging or cutting, and each said pair of plates are fitted
together with the recesses thereof opposed to each other and with
each of opposed pairs of channel dividing U-shaped ridges joined to
each other end-to-end to form a plurality of U-shaped divided fluid
passageways in the U-shaped fluid channel inside the flat tube.
[0017] A second mode of channel dividing ridges is as follows. Each
plate of said pairs has formed in the channel recess thereof front
and rear channel dividing ridges having a height twice the depth of
the channel recess and each comprising a straight portion
positioned in the front or rear straight channel recess portion of
the channel recess and a quarter circular-arc portion extending
from a lower end of the straight portion and positioned in the
return portion of the channel recess, the channel dividing ridges
being formed by forging or cutting and positioned alternately when
each of said pairs of plates are fitted together with their channel
recesses opposed to each other, each of said pairs of plates being
fitted together with their channel recesses opposed to each other
to join top ends of the front and rear channel dividing ridges to a
bottom wall flat surface of the plate providing the channel recess
and opposed thereto and to thereby form U-shaped divided fluid
passageways in the U-shaped fluid channel inside the flat tube.
[0018] A third mode of channel dividing ridges is as follows. Each
plate of said pairs has formed in the channel recess thereof
channel dividing ridges having a height twice the depth of the
channel recess and formed by forging or cutting so as to be
positioned alternately, when each of said pairs fitted together
with the recesses thereof opposed to each other, each of said pairs
of plates being fitted together to join top ends of the channel
dividing ridges on each plate of the pair to a flat surface of
bottom wall of the channel recess of the other plate opposed to
said each plate and to thereby form U-shaped divided fluid
passageways in the U-shaped fluid channel inside the flat tube.
[0019] A fourth mode of channel dividing ridges is as follows. Each
plate of said pairs has formed in a rear half of the channel recess
thereof channel dividing ridges having a height twice the depth of
the channel recess and formed by forging or cutting, the channel
recess of each plate having a front half in the form of a flat
surface provided by a bottom wall thereof and having no channel
dividing ridges, each of said pairs of plates being fitted together
with the recesses thereof opposed to each other to join top ends of
the channel dividing ridges thereof to the bottom wall flat surface
of the channel recess of the plate opposed to the dividing ridges
and to thereby form U-shaped divided fluid passageways in the
U-shaped fluid channel inside the flat tube.
[0020] With the heat exchanger having the first feature of the
invention, one of each pair of plates may be replaced by a flat
plate.
[0021] More specifically, the heat exchanger in this case comprises
ridged plates each having a peripheral ridge provided on one side
of the plate along a periphery thereof and a central ridge provided
on said one side of the plate at a center of the width thereof and
extending downward from an upper end of the plate to a position
where a return channel can be formed, the ridges being formed by
forging or cutting, each of the ridged plates having a U-shaped
channel recess formed inwardly of the peripheral ridge and
comprising a front and a rear channel recess portion formed on
opposite sides of the central ridge and a return channel recess
portion positioned under the central ridge, the channel recess
having one of two fluid inlet-outlet through holes formed at one
end thereof and the other through hole formed at the other end
thereof, each of the ridged plates having a flat surface on the
other side thereof and being fitted to each of flat plates
face-to-face, each of said flat plates having the same contour and
the same size as the ridged plate and two fluid inlet-outlet
through holes corresponding to said through holes, the peripheral
ridge of the ridged plate having a top end thereof joined to a
peripheral edge of the flat plate, the central ridge of the ridged
plate having a top end thereof joined to a flat surface of a
corresponding central portion of the flat plate, whereby a flat
tube having a U-shaped fluid channel inside thereof is formed so
that a plurality of flat tubes are arranged in parallel with a
header member interposed between upper ends of each pair of
adjacent flat tubes to provide a front and a rear header in
communication with the upper ends of the said pair of adjacent flat
tubes, the header member comprising a pair of front and rear fluid
passing tube portions in communications with the respective
inlet-outlet through holes of the plates of said pair of adjacent
flat tubes and a connecting portion between the tube portions.
[0022] With the heat exchanger having the second feature of the
invention, one of each pair of plates may be replaced by a flat
plate.
[0023] Stated more specifically, the heat exchanger in this case
comprises ridged plates each having an edge ridge U-shaped in its
entirety and provided on one side of the plate along opposite side
edges and a lower edge thereof and a central ridge provided on said
one side of the plate at a center of the width thereof and having a
bifurcated upper end, the central ridge extending from the upper
end downward to a position where a return channel can be formed,
the ridges being formed by forging or cutting, each of the ridged
plates having a U-shaped channel recess formed inwardly of the
U-shaped edge ridge and comprising a front and a rear channel
recess portion formed on opposite sides of the central ridge and a
return channel recess portion positioned under the central ridge,
each of the ridged plates having a flat surface on the other side
thereof and being fitted to each of flat plates face-to-face, each
of said flat plates having the same contour and the same size as
the ridged plate, the peripheral ridge of the ridged plate having a
top end thereof joined to a peripheral edge of the flat plate, the
central ridge of the ridged plate including the bifurcated upper
ends having a top end thereof joined to a flat surface of a
corresponding central portion of the flat plate, whereby a flat
tube having bifurcated open upper ends and a U-shaped fluid channel
inside thereof is formed, a pair of front and rear header members
being each in the form of a pipe having a rectangular cross
section, each of the header members having slits formed in a lower
wall thereof and arranged at a predetermined spacing, a plurality
of flat tubes being arranged in parallel by inserting the
bifurcated open upper ends thereof into the respective slits in the
front and rear header members to join the flat tubes to the header
members and to provide a front and a rear header in communication
with the bifurcated open upper ends of the flat tubes.
[0024] In a heat exchanger having such flat plates, a plurality of
channel dividing U-shaped ridges are formed in the U-shaped channel
recess of each ridged plate by forging or cutting, and each ridged
plate and each flat plate are fitted together face-to-face with the
channel dividing U-shaped ridges of the ridged plate joined to the
flat surface of the corresponding central portion of the flat plate
to form a plurality of U-shaped divided fluid passageways in the
U-shaped fluid channel inside the flat tube.
[0025] Third, the present invention provides a heat exchanger which
is characterized in that the heat exchanger comprises pairs of
plates with each plate of the pairs having a peripheral ridge
provided on one side of the plate along a periphery thereof and a
central ridge provided on said one side of the plate at a center of
the width thereof and extending vertically, the ridges being formed
by forging or cutting, each plate of said pairs having a front and
a rear channel recess portion formed inwardly of the peripheral
ridge on opposite sides of the central ridge, each of the front and
rear channel recess portions having a through hole formed in each
of upper and lower ends thereof, each plate of said pairs having a
flat surface on the other side thereof, each of said pairs of
plates being fitted together with their channel recess portions
opposed to each other to join the opposed peripheral ridges to each
other end-to-end and the opposed central ridges to each other
end-to-end and to thereby form a flat tube having a front and a
rear fluid channel inside thereof so that a plurality of flat tubes
are arranged in parallel with an upper and a lower header member
interposed respectively between upper ends of each pair of adjacent
flat tubes and between lower ends thereof to provide an upper and a
lower header in communication with the upper ends and the lower
ends of said pair of adjacent flat tubes, each of the header
members comprising a pair of front and rear fluid passing tube
portions in communications with the corresponding through holes of
the plates of said pair of adjacent flat tubes and a connecting
portion between the tube portions.
[0026] Fourth, the present invention provides a heat exchanger
which is characterized in that the heat exchanger comprises pairs
of plates with each plate of the pairs having a side edge ridge
provided on one side of the plate along each of opposite side edges
thereof and a central ridge provided on said one side of the plate
at a center of the width thereof and having a bifurcated upper and
a bifurcated lower end, the ridges being formed by forging or
cutting, each plate of said pairs having a front and a rear channel
recess portion formed inwardly of the side edge ridges on opposite
sides of the central ridge, each plate of said pairs having a flat
surface on the other side thereof, each of said pairs of plates
being fitted together with their channel recess portions opposed to
each other to join the opposed side edge ridges to each other
end-to-end and the opposed central ridges including the bifurcated
upper and lower ends to each other end-to-end and to thereby form a
flat tube having bifurcated open upper and lower ends and a front
and a rear fluid channel inside thereof, an upper pair of front and
rear header members and a lower pair of front and rear header
members being each in the form of a pipe having a rectangular cross
section, each of the header members having slits formed in an upper
wall or a lower wall thereof and arranged at a predetermined
spacing, a plurality of flat tubes being arranged in parallel by
inserting the bifurcated upper or lower ends thereof into the
respective slits in the header members to join the flat tubes to
the header members and to provide an upper pair of front and rear
headers and a lower pair of front and rear headers in communication
with the bifurcated upper and lower ends of the flat tubes
respectively.
[0027] With the heat exchanger having the third or fourth feature
described, a plurality of channel dividing ridges are formed in the
front and rear channel recesses of each plate by forging or
cutting, and a pluralty of divided fluid passageways are formed in
the front and rear fluid channels in the interior of each flat
tube. The invention provides several modes of channel dividing
ridges.
[0028] As a first mode, a plurality of channel dividing ridges are
formed in the front and rear channel recess portions of each plate
by forging or cutting, and each of said pairs of plates are fitted
together with their recess portions opposed to each other to join
each of opposed pairs of the channel dividing ridges to each other
end-to-end and form divided fluid passageways in the front and rear
fluid channels inside thereof.
[0029] A second mode of channel dividing ridges is as follows. Each
plate has formed in the respective front and rear channel recess
portions thereof front and rear channel dividing ridges having a
height twice the depth of the recess portion, the front and rear
channel dividing ridges being formed by forging or cutting and
positioned alternately when each of said pairs of plates are fitted
together with their recess portions opposed to each other, each of
said pairs of plates being fitted together face-to-face to join top
ends of the front and rear channel dividing ridges to a bottom wall
flat surface of recess portion of the plate opposed thereto and to
thereby form divided fluid passageways in the front and rear fluid
channels inside the flat tube.
[0030] A third mode of channel dividing ridges is as follows. Each
plate of the pairs has formed in each of the front and rear channel
recess portions thereof a channel dividing ridge having a height
twice the depth of the recess portion, the channel dividing ridge
being so formed by forging or cutting that the front and rear
channel dividing ridges of each pair of plates as fitted together
face-to-face are positioned alternately, each pair of plates being
fitted together with their recess portions opposed to each other to
join top ends of the front and rear channel dividing ridges of each
plate of the pair to a bottom wall flat surface of the recess
portion of the other plate of the pair opposed thereto and to
thereby form divided fluid passageways in the front and rear fluid
channels inside the flat tube.
[0031] A fourth mode of channel dividing ridges is as follows. Each
plate has formed in one of the front and rear channel recess
portions thereof a plurality of channel dividing ridges having a
height twice the depth of the recess portion, the channel dividing
ridges being formed by forging or cutting, the other channel recess
portion having a bottom wall flat surface having no channel
dividing ridges, each of said pairs of plates being fitted together
with their recess portions opposed to each other to join top ends
of the channel dividing ridges to the bottom wall flat surface of
the recess portion of the plate opposed thereto and to thereby form
divided fluid passageways in the front and rear fluid channels
inside the flat tube.
[0032] With the heat exchanger having the third feature of the
invention, one of each pair of plates may be replaced by a flat
plate.
[0033] Stated more specifically, the heat exchanger in this case
comprises ridged plates each having a peripheral ridge provided on
one side of the plate along a periphery thereof and a central ridge
provided on said one side of the plate at a center of the width
thereof and extending vertically, the ridges being formed by
forging or cutting, each the ridged plates having a front and a
rear channel recess portion formed inwardly of the peripheral ridge
on opposite sides of the central ridge, each of the front and rear
channel recess portions having a through hole formed in each of
upper and lower ends thereof, each of the ridged plates having a
flat surface on the other side thereof and being fitted to each of
flat plates face-to-face, each of said flat plates having the same
contour and the same size as the ridged plate and fluid
inlet-outlet through holes corresponding to said through holes, the
peripheral ridge of the ridged plate having a top end thereof
joined to a peripheral edge of the flat plate, the central ridge of
the ridged plate having a top end thereof joined to a flat surface
of a corresponding central portion of the flat plate, whereby a
flat tube having a front and a rear fluid channel inside thereof is
formed so that a plurality of flat tubes are arranged in parallel
with an upper and a lower header member interposed respectively
between upper ends of each pair of adjacent flat tubes and between
lower ends thereof to provide an upper and a lower header in
communication with the upper ends and the lower ends of said pair
of adjacent flat tubes, each of the header members comprising a
pair of front and rear fluid passing tube portions in
communications with the corresponding through holes of the plates
of said pair of adjacent flat tubes and a connecting portion
between the tube portions.
[0034] In the above heat exchanger, the connecting portion of one
of the upper and lower header members interposed between the upper
ends and lower ends of each pair of adjacent flat tubes may have a
passage interconnecting the fluid passing tube portions of the
header member.
[0035] With the heat exchanger having the fourth feature of the
invention, one of each pair of plates may be replaced by a flat
plate.
[0036] Stated more specifically, the heat exchanger then comprises
ridged paltes each having a side edge ridge provided on one side of
the plate along each of opposite side edges thereof and a central
ridge provided on said one side of the plate at a center of the
width thereof and having a bifurcated upper and a bifurcated lower
end, the ridges being formed by forging or cutting, each of the
ridged plates having a front and a rear channel recess portion
formed inwardly of the side edge ridges on opposite sides of the
central ridge, each of the ridged plates having a flat surface on
the other side thereof and being fitted to each of flat plates
face-to-face, each of said flat plates having the same contour and
the same size as the ridged plate, the side edge ridges of the
ridged plate having top ends thereof joined to side edges of the
flat plate, the central ridge of the ridged plate including the
bifurcated upper and lower ends having a top end thereof joined to
a flat surface of a corresponding central portion of the flat
plate, whereby a flat tube having bifurcated open upper and lower
ends and a front and a rear fluid channel inside thereof is formed,
an upper pair of front and rear header members and a lower pair of
front and rear header members being each in the form of a pipe
having a rectangular cross section, each of the header members
having slits formed in an upper wall or a lower wall thereof and
arranged at a predetermined spacing, a plurality of flat tubes
being arranged in parallel by inserting the bifurcated upper or
lower ends thereof into the respective slits in the header members
to join the flat tubes to the header members and to provide an
upper pair of front and rear headers and a lower pair of front and
rear headers in communication with the bifurcated upper and lower
ends of the flat tubes respectively.
[0037] In a heat exchanger wherein flat plates are used, each of
the ridged plates has channel dividing ridges formed in the
respective front and rear channel recess portions thereof by
forging or cutting, and each ridged plate is fitted to each flat
plate face-to-face to join top ends of the channel dividing ridges
to a flat surface of a corresponding portion of the flat plate and
to thereby form divided fluid passageways in the front and rear
fluid channels inside the flat tube.
[0038] In a heat exchanger which has the first or third feature,
the header member interposed between the ends of each pair of
adjacent flat tubes has its fluid passing tube portions joined at
their opposite end faces to the flat surfaces on the other sides of
the opposed plates of the pair of flat tubes. Preferably, tacks for
temporarily holding the header member are provided on respective
edges defining the inlet-outlet through holes in the end of each
plate.
[0039] In a heat exchanger according, a plurality of cutouts are
formed in the channel dividing ridges on each plate to cause the
adjacent divided fluid passageways inside the flat tube to
communicate with each other through the cutouts.
[0040] In any of the heat exchangers of the invention described, a
fin is provided between each pair of adjacent flat tubes included
in the flat tubes arranged in parallel, and the fin has opposite
sides edges thereof joined to the flat surfaces on the other sides
of the plates of the pair of flat tubes.
[0041] For use in any of the heat exchangers of the invention
described, the plates are those having recesses and ridges formed
on one side thereof by forging or cutting, in place of conventional
plates which are formed by press work, and the header members are
members separate from the plate for providing headers. These
features provide flat tubes having a reduced front-to-rear width, a
diminished wall thickness (layer of diminished thickness) and an
increased heat transfer area to result in the advantages of a
higher heat transfer efficiency and greatly improved heat exchange
performance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a perspective view of a heat exchanger according
to a first embodiment of the invention.
[0043] FIG. 2 is an enlarged front view of a plate of the heat
exchanger of FIG. 1.
[0044] FIG. 3 is an enlarged fragmentary perspective view of the
plate.
[0045] FIG. 4 is an enlarged exploded fragmentary perspective view
of the heat exchanger of FIG. 1.
[0046] FIG. 5 is an enlarged cross sectional view of a plate tube
of the heat exchanger.
[0047] FIG. 6 is an enlarged fragmentary perspective view partly
broken away and showing the heat exchanger.
[0048] FIG. 7 is an enlarged fragmentary cross sectional view
showing a modification of dividing ridges of plate of the heat
exchanger of FIG. 1.
[0049] FIG. 8 is an enlarged front view showing a modified plate of
the heat exchanger.
[0050] FIG. 9 is an enlarged fragmentary perspective view showing
another modified plate of the heat exchanger.
[0051] FIG. 10 is an enlarged cross sectional view of a flat tube
for the heat exchanger wherein the plate of FIG. 9 is used.
[0052] FIG. 11 is an enlarged exploded fragmentary perspective view
of a heat exchanger according to a second embodiment of the
invention.
[0053] FIG. 12 is an enlarged fragmentary front view of the plate
of the heat exchanger of FIG. 11, with headers also shown.
[0054] FIG. 13 is a perspective view of a heat exchanger according
to a third embodiment of the invention.
[0055] FIG. 14 is an enlarged front view of the plate of the heat
exchanger plate shown FIG. 13.
[0056] FIG. 15 is an enlarged fragmentary perspective view of the
heat exchanger plate.
[0057] FIG. 16 is an enlarged exploded perspective view of an upper
end portion of the heat exchanger.
[0058] FIG. 17 is an enlarged exploded perspective view of a lower
end portion of the heat exchanger.
[0059] FIG. 18 is an enlarged front view of a plate for use in the
heat exchanger of FIG. 1 to show a second modification of diving
ridges.
[0060] FIG. 19 is an enlarged cross sectional view of a flat tube
for the heat exchanger wherein the plate of FIG. 18 is used.
[0061] FIG. 20 is an enlarged front view of a plate for use in the
heat exchanger of FIG. 1 to show a third modification of diving
ridges, the plate being one of a pair of plates in combination.
[0062] FIG. 21 is an enlarged front view of the other plate of the
pair.
[0063] FIG. 22 is an enlarged front view of a plate for use in the
heat exchanger of FIG. 1 to show a fourth modification of diving
ridges.
[0064] FIG. 23 is an enlarged cross sectional view of a flat tube
for the heat exchanger wherein the plate of FIG. 22 is used.
[0065] FIG. 24 is an enlarged cross sectional view of a flat tube
of heat exchanger of the invention, wherein one of a pair of plates
in combination is replaced by a flat plate as a modification.
[0066] FIG. 25 is an enlarged cross sectional view of a flat tube
of an example of conventional heat exchanger.
BEST MODE OF CARRYING OUT THE INVENTION
[0067] Embodiments of the present invention will be described below
with reference to the drawings.
[0068] The terms "front," "rear," "left," "right," "upper" and
"lower" as used herein are based on FIG. 2; "front" refers to the
left-hand side of FIG. 2, "rear" to the right-hand side thereof,
"left" to the front side of the plane of the drawing, "right" to
the rear side of the plane thereof, "upper" to the upper side of
the drawing, and "lower" to the lower side thereof.
[0069] The drawings show heat exchangers of the invention for use
as evaporators for motor vehicle air conditioners.
[0070] FIGS. 1 to 6 show a first embodiment of the present
invention. A heat exchanger 1 for use as an evaporator is made from
aluminum (including aluminum alloys).
[0071] A generally rectangular plate 2 made of an aluminum plate
has a peripheral ridge 3 provided on one side of the plate 2 along
a periphery thereof and a central ridge 4 provided on the same side
of the plate 2 at the center of the width thereof and extending
downward from the upper end of the plate to a position where a
refrigerant return channel can be formed. Formed in the plate 2
internally of the peripheral ridge 3 is a U-shaped refrigerant
channel recess 6 comprising front and rear straight refrigerant
channel recess portions 6a, 6b positioned on opposite sides of the
central ridge 4 and a refrigerant return channel recess portion 6c
positioned under the central ridge.
[0072] According to this first embodiment, the plate 2 is provided
in the widthwise midportion of its upper end with a notch 14 which
is U-shaped when seen from the front. The central ridge 4 is joined
at its upper end to the peripheral ridge 3 at the lower end of this
notch 14.
[0073] The channel recess 6 has one of refrigerant inlet-outlet
through holes 10, 10 formed at one end thereof and the other
through hole 10 formed at the other end thereof. The plate 2 has a
plurality of channel diving U-shaped ridges 5 formed inside the
channel recess 6 and extending over the approximate entire length
thereof.
[0074] The presence of the notch 14 in the widthwise midportion of
upper end of the plate 2 positions the though holes 10, 10 as
spaced apart from each other by the width of the notch 14. This
serves to prevent unnecessary heat exchange between an incoming
portion of refrigerant having a low temperature and an outgoing
portion of refrigerant having a high temperature, and to prevent
the refrigerant introduced into an inlet header to be described
later from flowing into an outlet header through a short path.
[0075] The corners of return channel recess portion 6c of the
channel recess 6 have short circular-arc ridges 9 for achieving an
improved heat exchange efficiency at the corner portions.
[0076] Each plate 2 is formed, for example, by forging or cutting.
Plates 2 are provided in pairs, and each pair of plates 2 are
fitted together with their U-shaped channel recesses 6, 6 opposed
to each other to join the opposed peripheral ridges 3, 3 of the
plates 2, 2 to each other end-to-end, the opposed central ridges 4,
4 thereof to each other end-to-end and each of the opposed pairs of
channel dividing rides 5, 5 to each other end-to-end and to thereby
form a flat tube 12 having a U-shaped refrigerant channel 8 inside
thereof, with a plurality of U-shaped divided refrigerant
passageways 7 formed in the refrigerant channel 8 inside the flat
tube 12.
[0077] A clad material is used for each plate 2 which has a brazing
sheet affixed to one surface thereof, preferably each of the inner
and outer surfaces thereof. Such components can then be joined
together easily. The evaporator 1 of the present invention has
headers 23, 23 which interconnect flat tubes 12, 12 providing a
refrigerant circuit and which are formed in the following
manner.
[0078] A plurality of flat tubes 12 are arranged in parallel, with
a spectacle-shaped header member 20 interposed between the upper
ends of each pair of adjacent flat tubes 12, 12 to provide front
and rear headers 23, 23 in communication with the upper ends of the
pair of adjacent flat tubes 12. The header member 20 comprises a
pair of front and rear refrigerant passing tube portions 21, 21 in
communications with the respective inlet-outlet through holes 10,
10 of the plates 2 and a connecting portion 22 between the tube
portions. Opposite end faces of front and rear tube portions 21, 21
of the header member 20 are joined to flat surfaces provided by the
other sides of respective opposed plates 2, 2 of the pair of flat
tubes 12.
[0079] Below the headers 23, 23, a corrugated louver fin 24 for
effecting heat exchange with air is provided between the adjacent
flat tubes 12, 12. The fin 24 is joined at left and right sides
thereof to the flat surfaces of the plates 2, 2.
[0080] The corrugated louver fin 24 has louvers formed
simultaneously with bending for improved heat transfer.
[0081] The bottom of the U-shaped notch 14 formed in the widthwise
midportion of the upper end of each plate 2 needs to be positioned
below the connecting portion 22 of the spectacle-shaped header
member 20 so as to drain condensation water collecting in the
notch.
[0082] Tacks 13, 13 for temporarily holding the header member 20
are provided at the midportions of the lower edges defining the
respective inlet-outlet through holes 10, 10 in the upper end of
the plate 2. The header member 20 can be prevented from shifting by
these tacks 13, 13 during brazing.
[0083] With reference to FIGS. 1 and 4, a pair of side plates 25,
25 are arranged respectively at left and right ends of the
evaporator 1. The left side plate 25 of the pair is provided with
an inlet-outlet pipe connecting block 27 joined to the upper end
thereof. The side plate 25 has a pair of front and rear through
holes 26, 26 formed in the upper end thereof and communicating
respectively with a pair of front and rear through holes 28, 28
formed in the block 27. The holes 26, 26 of the side plate 25
communicate respectively with the tube portions 21, 21 of the
header member 20.
[0084] Incidentally, the side plate 25 need not be provided in the
case where the block 27 is attached directly to the plate 2 at the
left or right outer end of the evaporator 1. The block 17 may
alternatively be provided at an intermediate portion of the height
of the side plate 25.
[0085] The block 27 may further be provided at the midportion of
length of the evaporator 1, or may comprise an inlet pipe
connecting block and an outlet pipe connecting block which are
provided respectively at the left and right ends of the evaporator
so as to position an inlet and an outlet individually at the left
and right ends.
[0086] The evaporator components described are assembled and
thereafter joined together by brazing to fabricate the essential
portion of the evaporator 1.
[0087] The assembly is brazed in a vacuum, or in a furnace with use
of a fluorine-containing flux.
[0088] It is desirable to use a material of relatively high
strength for the header member 20 and the side plates 25 in view of
pressure resistance. It is especially desirable to use an aluminum
alloy containing magnesium added thereto.
[0089] In the case where the fluorine-containing flux is used, it
is desirable to use an aluminum alloy material having a magnesium
content preferably of up to 0.4% since this results in improvements
in bondability and strength.
[0090] The surfaces of the plate 2 and the corrugated fin 24 are
approximately flat so that the fin 24 can be joined to the flat
tube 12 nearly 100% to achieve highly efficient heat exchange
between the interior of the circuit of flat tubes 12 and the
corrugated fins 24.
[0091] The header member 20 providing the headers 23, 23 has a
generally spectacle-shaped section with two refrigerant channels,
one of which has the function of collecting or distributing an
incoming portion of refrigerant, with the other serving to collect
or distribute an outgoing portion of refrigerant.
[0092] When the heat exchanger of the present invention is used as
an evaporator 1, the refrigerant is introduced into the flat tubes
12 in the form of a mixture of a liquid and a gas. At this time,
the liquid refrigerant has a higher density than the gas and is
more readily subjected to an inertial force. The liquid refrigerant
has higher properties to advance straight than the gas. For this
reason, the liquid refrigerant tends to collect in a greater amount
at a header end remote from the inlet header. An uneven flow of the
liquid refrigerant upsets the balance of latent heat of
vaporization in various portions, contributing greatly to
impairment of performance. This can be precluded effectively by
causing the flat tube 12 to project into the header 23 to serve as
a baffle and diminish the properties of the liquid refrigerant to
advance straight.
[0093] The present invention is adapted to readily provide a baffle
structure, for example, by making the height b1 of the through hole
10 at the inlet side of the flat tube 12 smaller than the inside
diameter b2 of the refrigerant passing tube portion 21 of the
header member 20. The effect of a baffle is available alternatively
by reducing the cross sectional area of the front and rear tube
portions 21 of the header member 20 at one location or at a
plurality of locations and thereby producing flows of varying cross
sectional areas.
[0094] Such a procedure diminishes the property of the liquid
refrigerant of advancing straight through the headers 23, 23,
permitting the refrigerant to flow into the flat tubes 12 in
equally divided quantities.
[0095] When the percentage of projection of the flat tube 12 into
the header 23 in the evaporator 1 of the invention is defined
as:
(b2-b1)/b2
[0096] wherein b1 is the height of the through hole 10 at the inlet
side of the flat tube 12, and b2 is the inside diameter of the tube
portion 21 of the header member 20, the percentage of projection is
in the range of 10 to 60% to be suitable. If the percentage of
projection is less than 10%, no effect of baffle plate is
available, readily permitting occurrence of an uneven flow, whereas
if the percentage of projection is over 60%, the header 23 offers
increased resistance to the flow to entail impaired performance
undesirably.
[0097] As shown in detail in FIG. 5, it is especially desirable
that the U-shaped divided refrigerant passageways 7 formed in the
refrigerant channel 8 in the interior of each flat tube 12 be made
generally hexagonal in cross section by tapering the peripheral
ridges 3, 3 on the pair of the plates 2, 2 of the tube 12 toward
inward, tapering the central ridges 4, 4 thereon inward and
tapering the channel dividing ridges 5, 5 inward. The reason is
that it is advantageous to spread the liquid refrigerant into a
thin layer over the inner surface of the refrigerant channel 8 of
the flat tube 12 for heat transfer.
[0098] Among the U-shaped divided refrigerant passageways 7 formed
in the channel 8 inside the flat tube 12, the passageway 7a between
the peripheral ridge 3 and the channel dividing U-shaped ridge 5
has a hexagonal cross section with a large width, and the
passageways 7b between the ridges 5, 5 have a hexagonal cross
section with a small width.
[0099] On the other hand, when the U-shaped divided refrigerant
passageways 7 formed in the inside refrigerant channel 8 of the
flat tube 12 have a rectangular cross section, for example, as
shown in FIG. 7, the liquid refrigerant is liable to collect in
wall corners of the flat tube 12 if the circuit width is diminished
to give an increased surface area to the refrigerant because the
liquid refrigerant which flows at a lower rate than the gas is
forced toward the passageway ends. With the liquid refrigerant
required for evaporation forced toward end portions, the liquid
refrigerant will not adhere to the inner walls of the peripheral
ridges 3, 3, central ridges 4, 4 and channel dividing ridges 5, 5
in the flat tube 12 and will not be subjected to effective heat
exchange, so that the heat exchanger fails to exhibit the desired
performance.
[0100] When the divided refrigerant passageways 7 are made
generally hexagonal in cross section as seen in FIG. 5, the liquid
refrigerant collects in the recessed parts of intermediate portions
of the passageways 7 with the greatest ease, adhering to the
tapered surfaces of the peripheral ridges 3, 3, those of the
central ridges 4, 4 and those of the dividing ridges 5, 5 on the
pair of plates 2, 2 for effective heat transfer and enabling these
ridges to act effectively as interior fins to exhibit improved heat
transfer performance. As a result, the heat transfer portions in
the interior of the refrigerant passageways 7 are increased in the
area of effective parts to cool air to assure comfort.
[0101] However, the evaporator 1 of the invention may be so shaped
as shown in either one of FIGS. 5 and 7 because the entire width of
the channel for passing cold refrigerant is equal to the width of
contact of the corrugated fin 24 for the heat exchanger of the
invention to achieve a higher heat exchange efficiency than the
conventional one.
[0102] According to the first embodiment of the invention
described, the plate 2 is, for example, 10 to 40 mm in width and
0.25 to 1.0 mm in thickness.
[0103] The peripheral ridge 3 on the plate 2 is, for example, 0.25
to 1.0 mm in thickness and 0.5 to 2.0 mm in width. The central
ridge 4 on the plate 2 is, for example, 0.25 to 1.0 mm in thickness
and 0.5 to 2.0 mm in width. The channel dividing U-shaped ridge 5
on the plate 2 is, for example, 0.25 to 1.0 mm in thickness and
0.25 to 1.0 mm in width.
[0104] With the evaporator 1 described above, the refrigerant
introduced into the front header 23 through one of the through
holes 28, i.e., the inlet hole 28, in the pipe connecting block 27
flows into divided refrigerant passageways 7 from one end of the
U-shaped refrigerant channel 8 of each flat tube 12, flows through
the U-shaped passageways 7 to the other end of the channel 8,
further passes through the rear header 23 and the other through
hole 28, i.e., the outlet hole 28, in the block 27 and flows out of
the evaporator.
[0105] On the other hand, air flows through the evaporator 1 from
the front rearward through the spaces each having the corrugated
louver fin 24 therein and formed between the adjacent flat tubes 12
and between the tube 12 and each end plate 25 to undergo efficient
heat exchange with the refrigerant through the walls of the flat
tube 12, the end plates 25 and the louver fins 24.
[0106] The evaporator 1 according to the first embodiment is
fabricated from plates which have recesses and ridges formed on one
side thereof as by forging or cutting and which are used in place
of conventional plates formed by press work. The front and rear
headers are formed by header members which are separate from the
plates. These features give the flat tubes 12 a reduced
front-to-rear width and a decreased thickness (thinner layers) and
afford a greater area of heat transfer, enabling the evaporator to
achieve a higher heat transfer efficiency and exhibit greatly
improved heat exchange performance.
[0107] To assure the refrigerant of improved heat transfer in the
flat tube 12, it is desired that a plurality of cutouts 15 be
formed in the channel dividing U-shaped ridges 5 on each plate 2 at
a predetermined spacing, for example as shwon in FIG. 8, the
cutouts 15 in the adjacent ridges 5 being in a staggered
arrangement, so as to cause the divided adjacent refrigerant
passageways 7, 7 in the interior of the tube 12 to communicate with
each other through the cutouts 15.
[0108] Alternatively, the flat tube 12 may have turbulence
promoting members (projections) 16 in a staggered arranged for
producing turbulent flows of refrigerant for improved heat
transfer, for example, as shown in FIGS. 9 and 10.
[0109] FIGS. 11 and 12 show a second embodiment of the invention.
This embodiment differs from the first in that a pair of front and
rear header members 41, 42 each in the form of a pipe having a
rectangular cross section are used.
[0110] Stated more specifically, an evaporator 1 is fabricated from
generally rectangular plates 2 which are aluminum plates. Each of
these plates 2 has an edge ridge 33 provided on one side of the
plate along opposite side edges and a lower edge thereof and
U-shaped in its entirety, and a central ridge 34 provided on the
same side of the plate 2 at the center of the width thereof and
having a bifurcated upper end 34a, the central ridge 34 extending
from the upper end 34a downward to a position where a refrigerant
return channel can be formed. The plate 2 has a U-shaped
refrigerant channel recess 36 formed internally of the U-shaped
edge ridge 33 and comprising front and rear straight refrigerant
channel 25 recess portion 36a, 36a formed on opposite sides of the
central ridge 34 and a refrigerant return channel recess portion
36c positioned under the central ridge. The plate 2 has a plurality
of channel diving U-shaped ridges 35 formed inside the channel
recess 36 and extending over the approximate entire length
thereof.
[0111] The corners of return channel recess portion 36c of the
channel recess 36 has short circular-arc ridges 39 for achieving an
improved heat exchange efficiency at the corner portions.
[0112] According to this second embodiment, the plate 2 is provided
in the widthwise midportion of its upper end with a notch 37 which
is U-shaped when seen from the front. The central ridge 34 has the
bifurcated upper end 34a.
[0113] Each plate 2 is formed, for example, by forging or cutting.
Plates 2 are provided in pairs, and each pair of plates 2 are
fitted together with their U-shaped channel recesses 36, 36 opposed
to each other to join the opposed U-shaped edge ridges 33, 33 of
the plates 2, 2 to each other end-to-end, the opposed central
ridges 34, 34 including the bifurcated upper ends 34a to each other
end-to-end and each of the opposed pairs of channel dividing rides
5, 5 each other end-to-end and to thereby form a flat tube 32
having upper ends 32a, 32a which are bifurcated and opened, with a
plurality of U-shaped divided refrigerant passageways formed inside
the flat tube 32.
[0114] On the other hand, a pair of front and rear header members
41, 42 are each in the form of a pipe rectangular in cross section
and having a lower wall 43, front wall 45, rear wall 46 and upper
wall 47. The header members 41, 42 have slits 44, 44 formed in the
respective lower walls 43, 43 thereof and arranged at a
predetermined spacing. Flat tubes 32 are arranged in parallel
laterally, with a front and a rear header provided in communication
with the bifurcated open upper ends 32a, 32a of the flat tubes 32,
by inserting the bifurcated open upper ends 32a, 32a thereof into
the respective slits 44, 44 of the juxtaposed header members 41, 42
and thereby joining the flat tubes to the header members. At this
time, the rear wall 46 and the front wall 45 of the respective
juxtaposed front and rear header members 41, 42 are fitted as
joined together into U-shaped notches 37, 37 in the upper ends of
the opposed plates 2, 2 of each flat tube 32.
[0115] Below the headers, a corrugated fin 24 is provided between
the adjacent flat tubes 32, 32. The fin 24 is joined at left and
right sides thereof to the flat surfaces provided by the other
sides of the plates 2, 2.
[0116] The evaporator 1 of the second embodiment is fabricated in
the same manner as the first in that the assembly of components is
brazed in a vacuum, or in a furnace with use of a
fluorine-containing flux, so that throughout the drawings
concerned, like parts are designated by like reference
numerals.
[0117] Although not shown, the pair of front and rear header
members 41, 42 each in the form of rectangular pipe may be replaced
by a single aluminum extrudate having two refrigerant channels
generally rectangular in cross section and partitioned by a central
wall for use in the evaporator 1 according to the second embodiment
described. The extrudate has slits 44, 44 formed in the respective
portions of a lower wall thereof which define the refrigerant
channels and arranged at a predetermined spacing. A front and a
rear header are provided in communication with the bifurcated open
upper ends 32a, 32a of the juxtaposed flat tubes 32 by inserting
the bifurcated open upper ends 32a, 32a the tubes into the
respective slits 44, 44 and thereby joining the tubes to the lower
wall.
[0118] FIGS. 13 to 17 show a third embodiment of the present
invention, which differs from the first in that headers 57 and
headers 58 are provided respectively at the top and bottom of an
evaporator 1.
[0119] With reference to these drawings, a generally rectangular
plate 2 made of an aluminum plate has a peripheral ridge 3 provided
on one side of the plate 2 along a periphery thereof and a central
ridge 4 provided on the same side of the plate 2 at the center of
the width thereof and extending vertically. Formed in the plate 2
internally of the peripheral ridge 3 are front and rear refrigerant
channel recess portions 6a, 6b positioned on opposite sides of the
central ridge 4 and through holes 10, 10 formed in the upper and
lower ends of the recess portions 6a, 6b. The plate 2 has straight
channel diving ridges 5 formed inside the channel recess portions
6a, 6b and extending over the approximate entire length of the
portions 6a, 6b.
[0120] The plate 2 is formed, for example, by forging or cutting.
Such plates 2 are provided in pairs, and each pair of plates 2 are
fitted together with their recess portions 6a, 6b opposed to each
other to join the opposed peripheral ridges 3, 3 of the plates 2, 2
to each other end-to-end, the opposed central ridges 4, 4 thereof
to each other end-to-end and each of the opposed pairs of channel
dividing rides 5, 5 to each other end-to-end and to thereby form a
flat tube 12 having a U-shaped refrigerant channel 8 inside
thereof, with parallel divided refrigerant passageways 7 formed in
the inside the flat tube 12 (see FIG. 7 of the first
embodiment).
[0121] A required number of flat tubes 12 are arranged side by
side. Spectacle-shaped upper and lower header members 51, 52, each
comprising a pair of front and rear refrigerant passing tube
portions 53, 53 or 54, 54 and a connecting portion 55 or 56
therebetween, are interposed respectively between the upper ends of
each pair of adjacent flat tubes and between the lower ends
thereof, the tube portions 53 or 54 being in communication with the
corresponding through holes 10 of the opposed plates 2.
[0122] As shown in detail in FIG. 14, of the pairs of front and
rear through holes 10, 10 formed in the upper and lower ends of the
plate 2, the pair of front and rear through holes 10a, 10a in the
upper end of the plate 2 are each in the form of a circle which is
elongated horizontally. In corresponding relation with these holes,
the front and rear tube portions 53, 53 of the upper header member
51 provided between the upper ends of the flat tubes 12, 12 have a
circular cross section which is similarly elongated horizontally.
On the other hand, the pair of front and rear through holes 10b,
10b in the lower end of the plate 2 are each in the form of a
circle which is elongated as inclined forwardly downward or
rearwardly downward. In corresponding relation with these holes,
the front and rear tube portions 54, 54 of the lower header member
52 provided between the lower ends of the flat tubes 12, 12 have a
circular cross section which is similarly elongated as inclined
forwardly downward or rearwardly downward.
[0123] With reference to FIGS. 16 and 17, opposite end faces of the
tube portions 53, 53 and 54, 54 of the upper and lower header
members 51, 52 are joined to flat surfaces on the other sides of
the plates of the flat tubes 12, 12 which surfaces are opposed to
the end faces, whereby upper and lower headers 57, 58 are formed in
communication respectively with the upper ends and lower ends of
the flat tubes 12, 12.
[0124] Between the upper and lower headers 57, 58, a corrugated
louver fin 24 for effecting heat exchange with air is interposed
between each pair of adjacent flat tubes 12, 12. The fin 24 is
joined at opposite side edges thereof to the other sides, i.e., the
flat surfaces of the plates 2, 2 of the flat tubes 12, 12.
[0125] Of the upper and lower header members 51, 52 between the
adjacent flat tubes 12, 12 in the evaporator 1 of the third
embodiment, the lower header member 52 has passages 59, 59 formed
at opposite sides of the intermediate connecting portion 56 for
interconnecting the front and rear tube portions 54, 54 of the
header member 52.
[0126] With the evaporator 1 of the third embodiment described, the
refrigerant is introduced from an inlet through hole 18 in an
inlet-outlet pipe connecting block 27 into the front tube portion
53 of each upper header member 51 providing the front upper header
57, from which the refrigerant flows into the front upper end of
refrigerant channel 8 of each flat tube 12, further flows down the
straight divided refrigerant passageways 7 to reach the front lower
end of the channel 8, from which the refrigerant temporarily flows
into the front tube portion 54 of the lower header member 52
providing the front lower header 58, then passes through the
interconnecting passages 59, 59 in the lower header member 52 and
flows into the rear tube portion 54 providing the rear lower header
58. Subsequently, the refrigerant flows into the rear lower end of
the refrigerant channel 8 of the flat tube 12, further ascends the
straight divided refrigerant passageways 7 to reach the rear upper
end of the channel 8, passes through the rear tube portion 53 of
the upper header member 51 providing the rear upper header 57 and
flows out of an outlet through hole 28 in the block 27.
[0127] With the evaporator 1 of the third embodiment, the front and
rear tube portions 54, 54 of the lower header member 52 between the
lower ends of the flat tubes 12, 12 have a circular cross section
which is elongated as inclined forwardly downward or rearwardly
downward so as to cause the water produced upon condensation on the
outer surface of the evaporator 1 during due to be drained
smoothly.
[0128] Although not shown, the evaporator 1 of the third embodiment
may also be modified like the modification of FIG. 8, by forming a
plurality of cutouts 15 in the channel dividing ridges 5 on each
plate so that the adjacent divided refrigerant passageways 7, 7
inside the flat tube 12 communicate with each other through the
cutouts 15.
[0129] Of the upper and lower header members 51, 52 provided
between the adjacent flat tubes 12, 12 at their upper ends and
lower ends in the evaporator 1 of the third embodiment, the upper
header member 51 may have passages 59, 59 formed at opposite sides
of the intermediate connecting portion 55 for interconnecting the
front and rear tube portions 53, 53 of the header member 51, in
converse relation with the illustrated case so as to cause the
refrigerant to flow in the opposite direction to the illustrated
case.
[0130] The evaporator 1 of the third embodiment otherwise has the
same construction as the first embodiment described, so that like
parts are designated by like reference numerals throughout the
drawings concerned.
[0131] FIGS. 18 and 19 show a second modification of channel
dividing ridges 5 on the plate 2 for use in the evaporator
according to the first embodiment of the invention, i.e., channel
dividing ridges 5a, 5b formed in the refrigerant channel recess 6
of each plate 2, which differ from the channel dividing U-shaped
ridges 5 shown in FIGS. 2, 3 and 5 showing the first embodiment in
configuration and arrangement. Another difference is that the
ridges 5a, 5b on each plate 2 have top ends joined to the flat
bottom wall of the plate 2 opposed thereto and providing the
refrigerant channel recess 6 thereof.
[0132] With reference to FIGS. 18 and 19, each plate 2 of the
evaporator 1 has on one side thereof a peripheral ridge 3 along the
periphery thereof and a central ridge 4 at the center of the width
of the plate and extending downward from the upper end of the plate
to a position where a return channel can be formed. More
specifically, each pair of plates 2a, 2b have formed in a
refrigerant channel recess 6 thereof a multiplicity of front and
rear channel dividing ridges 5a, 5b having a height twice the depth
of the channel recess 6. These ridges 5a, 5b are so provided as to
form independent parallel U-shaped divided refrigerant passageways
7 in a U-shaped refrigerant channel 8 of a flat tube 12 when the
pair of plates 2a, 2b are fitted together.
[0133] With reference to FIG. 18, these ridges 5a, 5b each comprise
a straight portion 5a1 or 5b1 positioned in the front or rear
straight channel recess portion 6a or 6b of the refrigerant channel
recess 6 and a quarter circular-arc portion 5a2 or 5b2 extending
from the straight portion and positioned in the return portion 6c
of the recess 6. The ridges 5a, 5b correspond to exactly half of a
U-shape in configuration.
[0134] When the pair of plates 2a, 2b are fitted together with the
recesses 6, 6 opposed to each other, the straight portions 5a1, 5b1
and quarter circular-arcs 5a2, 5b2 of these ridges 5a, 5b are
alternately arranged at a predetermined spacing.
[0135] With the pair of plates 2a, 2b fitted together, the opposed
central ridges 4, 4 are butted against and joined to each other,
with the peripheral ridges 3, 3 similarly joined to each other, and
the straight portions 5a1, 5b1 and the quarter circular-arcs 5a2,
5b2 of the channel dividing ridges 5a, 5b on each of the plates 2a,
2b are joined at their top ends to the bottom wall flat surface of
the other plate 2a or 2b opposed thereto and providing the channel
recess 6, whereby a flat tube 12 is formed with a U-shaped
refrigerant channel 8 formed therein. In the channel 8 of the flat
tube 12, the front channel dividing ridges 5a on the plate 2a of
the pair 2a, 2b are joined in a U-form to the rear ridges 5b on the
other plate 2b, providing divided parallel U-shaped refrigerant
passageways 7. The divided passageways 7 in the return portion are
in the form of semicircular arcs.
[0136] The return channel recess portion 6c of the U-shaped channel
recess 6 is provided at the corners on front and rear sides with
short circular-arc ridges 9a, 9b to ensure improved heat exchange
performance of this portion. These circular-arc ridges 9a, 9b are
so arranged as to be positioned alternately at a predetermined
spacing when the pair of plates 2a, 2b are fitted together with the
recesses 6, 6 thereof opposed to each other.
[0137] The above modification is the same as the first embodiment
otherwise; for example, each plate 2 is made by forging or cutting.
Throughout the drawings concerned, therefore, like parts are
designated by like reference numerals.
[0138] With the evaporator 1 described above, the front and rear
channel dividing ridges 5a, 5b on the pair of plates 2a, 2b
comprise straight portions 5a1, 5b1 and quarter circular-arc
portions 5a2, 5b2 and are shaped to correspond to exactly half of a
U-shape. These ridges 5a, 5b are so arranged that when the pair of
plates 2a, 2b are fitted together with the recesses 6, 6 opposed to
each other, the ridges 5a, 5b are positioned alternately at a
predetermined spacing. Accordingly, the number of dividing ridges
5a, 5b to be made as by forging or cutting can be diminished, while
the ridges 5a, 5b on the plates 2a, 2b can be spaced apart by an
increased interval and can be shaped to have exactly half of the
U-shape, hence the advantage that the plates 2a, 2b are easy to
produce.
[0139] FIGS. 20 and 21 show a third modification of channel
dividing ridge 5 on the plate 2 for use in the evaporator 1
according to the first embodiment of the invention. The
modification differs from the first embodiment in that two kinds of
plates 2a, 2b have channel dividing U-shaped ridges 5a, 5b which
are different in arrangement in refrigerant channel recesses 6, 6,
and that the ridges 5a, 5b on the plates 2a, 2b have their top ends
joined to the bottom wall flat surface of the recesses 6 of the
plates 2b, 2a opposed thereto.
[0140] With reference to the same drawings, the channel dividing
U-shaped ridges 5a, 5b having a height twice the depth of recesses
6, 6 are provided in the U-shaped recesses 6, 6 of the pair of
plates 2a, 2b so as to be alternately positioned at a predetermined
spacing when these plates 2a, 2b are fitted together
face-to-face.
[0141] With these plates 2a, 2b fitted together face-to-face, the
opposed central ridges 4, 4, as well as the opposed plate
peripheral ridges 3, 3, are butted against and joined to each
other, and the channel dividing U-shaped ridges 5a, 5b on the
plates 2a, 2b have their top ends joined to the bottom wall flat
surfaces of the recesses 6, 6 of the plates 2b, 2a opposed thereto,
whereby a flat tube 12 is formed which has parallel U-shaped
refrigerant passageways 7 divided by the ridges 5a, 5b and provided
in the U-shaped refrigerant channel 8.
[0142] In the front and rear corners of the refrigerant return
channel recess portions 6c of the U-shaped refrigerant channel
recesses 6, 6, short circular-arc ridges 9a, 9b are provided for
these portions to exhibit improved heat exchange performance. These
front and rear short circular-arc ridges 9a, 9b are alternately
positioned at a predetermined spacing when the pair of plates 2a,
2b are fitted together face-to-face.
[0143] The above modification is the same as the first embodiment
otherwise; for example, each plate 2 is made by forging or cutting.
Throughout the drawings concerned, therefore, like parts are
designated by like reference numerals.
[0144] With the evaporator 1 wherein the two kinds of plates 2a, 2b
are used, the channel dividing U-shaped ridges 5a, 5b on the two
plates 2a, 2b are so arranged that when these plates 2a, 2b are
fitted together face-to-face, the ridges 5a, 5b are positioned
alternately at a predetermined spacing. Accordingly, the number of
dividing ridges 5a, 5b to be made as by forging or cutting can be
smaller, while the ridges 5a, 5b on the plates 2a, 2b can be spaced
apart by an increased interval, hence the advantage that the plates
2a, 2b are easy to produce.
[0145] FIGS. 22 and 23 show a fourth modification of channel
dividing ridge 5 on the plate 2 for use in the evaporator 1
according to the first embodiment of the invention. The
modification differs from the first embodiment in that a
multiplicity of channel dividing ridges 5 are provided only in the
rear half of the refrigerant channel recess 6 of each plate 2, with
no ridges 5 whatever provided in the front half of the recess 6 and
with the front half made flat-surfaced, in that the ridges 5 are
shaped to have exactly half of a U-shape, and in that the ridges 5
on each plate 2 have their top ends joined to the bottom wall flat
surface of the recess 6 of the other plate 6 opposed thereto.
[0146] With reference to the same drawings, each plate 2 of the
evaporator 1 has a peripheral ridge 3 provided on one side of the
plate along a periphery thereof and a central ridge 4 provided on
the same side of the plate at the center of the width thereof and
extending downward from an upper end of the plate to a position
where a return channel can be formed. A multiplicity of channel
dividing ridges 5b having a height twice the depth of the recess 6
are provided in the rear half of the refrigerant channel recess 6
of each plate 2, with no ridges 5 whatever provided in the front
half of the recess 6 and with the front half made
flat-surfaced.
[0147] Stated more specifically with reference to FIG. 22, the
channel dividing ridges 5b provided in the rear half of the
refrigerant channel recess 6 of each plate 2 each comprise a
straight portion 5b1 formed in a rear straight channel recess
portion 6b and a quarter circular-arc portion 5b2 extending from
the straight portion and provided in a return portion 6c of the
recess 6, the ridges 5b being shaped to have exactly half of a
U-shape.
[0148] With a pair of plates 2a, 2b fitted together face-to-face,
the opposed central ridges 4, 4, as well as the opposed plate
peripheral ridges 3, 3, are butted against and joined to each
other, and the channel dividing U-shaped ridges 5, 5 on the plates
2a, 2b have their top ends joined to the bottom wall flat surfaces
of the refrigerant channel recesses 6, 6 of the plates 2b, 2a
opposed thereto, whereby a flat tube 12 is formed which has a
U-shaped refrigerant channel 8. The front ridges 5a on one plate 2a
of the two 2a, 2b are made continuous with the rear ridges 5b on
the other plate 2b, whereby parallel U-shaped divided refrigerant
passageways 7 are formed in the U-shaped refrigerant channel 8 of
the flat tube 12. The passageways 7 have semicircular-arc return
portions.
[0149] Short circular-arc ridges 9 are provided on the rear corner
portion of the return channel recess portion 6c of the recess 6 for
this portion to exhibit improved heat exchange performance.
[0150] The above modification is the same as the first embodiment
otherwise; for example, each plate 2 is made by forging or cutting.
Throughout the drawings concerned, therefore, like parts are
designated by like reference numerals.
[0151] With the evaporator 1, the channel dividing ridges 5 on each
plate 2 each comprise a straight portion 5b1 and a quarter
circular-arc portion 5b2 extending therefrom and are shaped to have
exactly half of a U-shape, while the front half of the recess 6 of
each plate 2 has a flat surface provided with no channel dividing
ridges 5. Accordingly, the ridges 5 to be formed on the plate 2 as
by forging or cutting can be half, hence the advantage that the
plates 2a, 2b are easy to make.
[0152] FIG. 24 shows a pair of plates for use in the evaporator 1
of the first embodiment of the invention, with one of the plates
replaced by a flat plate.
[0153] With reference to the drawing, the ridged plate 2 of the
first embodiment, i.e., the plate 2b comprises, as will be apparent
from FIG. 2, a peripheral ridge 3 provided on one side of the plate
along a periphery thereof and a central ridge 4 provided on the
same side of the plate at the center of the width thereof and
extending downward from the upper end of the plate to a position
where a refrigerant return channel can be formed. Formed in the
plate internally of the peripheral ridge 3 is a U-shaped
refrigerant channel recess 6 comprising front and rear straight
refrigerant channel recess portions 6a, 6b positioned on opposite
sides of the central ridge 4 and a refrigerant return channel
recess portion 6c positioned under the central ridge. The plate has
a plurality of channel diving U-shaped ridges 5 formed inside the
channel recess 6 and extending over the approximate entire length
thereof. The plate 2b is provided in the widthwise midportion of
its upper end with a notch 14 which is U-shaped when seen from the
front. The central ridge 4 is joined at its upper end to the
peripheral ridge 3 at the lower end of this notch 14. The channel
recess 6 of the plate 2b has one of refrigerant inlet-outlet
through holes 10, 10 formed at one end thereof and the other
through hole 10 formed at the other end thereof.
[0154] The flat plate 2a, on the other hand, has no U-shaped recess
nor any channel dividing U-shaped ridge but has a flat surface and
the same contour as the ridge plate 2b. The plate 2a is provided at
the widthwise midportion of its upper end with a notch which is
U-shaped when seen from the front. The flat plate 2a further has
refrigerant inlet-outlet through holes formed in its upper end at
front and rear sides thereof (not shown).
[0155] Such flat plates 2a and ridged plates 2b are provided in
pairs, with each pair of plates fitted together face-to-face. The
peripheral ridge 3 on the ridged plate 2b has its top end joined to
the flat surface of the peripheral edge portion of the flat plate
2a, with the top end of the central ridge 4 joined to the flat
surface of the central portion of the flat plate 2a, and with the
top ends of the ridges 5 joined to the corresponding flat surface
portions of the flat plate 2a, whereby a flat tube 12 is formed
which has a U-shaped refrigerant channel 8, with a plurality of
divided refrigerant passageways 7 formed in the channel 8.
[0156] The evaporator 1 comprising flat plates 2a described is the
same as the first embodiment otherwise; for example, the ridged
plate 2b is made as by forging or cutting. Throughout the drawings
concerned, therefore, like parts are designated by like reference
numerals.
[0157] The evaporator 1 comprises ridged plates 2b having a
peripheral ridge 3, central ridge 4 and channel dividing ridges 5,
and flat plates 2a having the same contour as the plate 2b. This
serves to halve the number of ridged plates 2b used which are
prepared as by forging or cutting, consequently entailing the
advantage of making the evaporator 1 easy to fabricate.
[0158] The evaporator 1 can be modified as will be described below
which is the second embodiment of the invention shown in FIGS. 11
and 12 and wherein a pair of front and rear header members 41, 42
used are each in the form of a pipe of rectangular cross
section.
[0159] Like the modification shown in FIGS. 18 and 19, the first of
modifications has a multiplicity of channel diving ridges 5a, 5b
formed in the channel recess 6 of each plate 2, comprising straight
portions 5a1, 5b1 and quarter circular-arc portions 5a2, 5b2
extending therefrom, and having exactly half of a U-shape and a
height twice the depth of the recess 6. When a pair of plates 2a,
2b are fitted together face-to-face, a flat tube 12 is formed
wherein the ridges 5a, 5b form independent parallel U-shaped
divided refrigerant passageways 7 in a U-shaped refrigerant channel
8. The ridges 5a, 5b of each plate 2 have their top ends joined to
the bottom wall flat surface of the recess 6 of the other plate 2
opposed to the ridges.
[0160] Like the modification shown in FIGS. 20 and 21, two kinds of
plates 2a, 2b can be used in the second modification to be
described below. The plates 2a, 2b have channel dividing U-shaped
ridges 5a, 5b which are different in arrangement in refrigerant
channel recesses 6, 6, and have a height twice the depth of the
recesses 6, 6. In this case, the ridges 5a, 5b on each of the
plates 2a, 2b have their top ends joined to the bottom wall flat
surface of the recesses 6 the other of these plates 2b, 2a opposed
thereto.
[0161] As is the case with the embodiment shown in FIGS. 22 and 23,
usable in a third modification are plates 2 which have a
multiplicity of channel dividing ridges 5 formed only in the rear
half of the refrigerant channel recess 6. The front half of the
recess 6 has no ridges whatever and is flat-surfaced. In this case,
the ridges 5 on each plate 2 have their top ends joined to the
bottom wall flat surface of the recess 6 of the other plate 2
opposed thereto.
[0162] As is the case with the flat tube shown in FIG. 24, usable
in a fourth modification in combination with a ridged plate 2b
which is the plate 2 of the second embodiment of FIG. 12 is a flat
plate 2a having the same contour as the plate 2b. In this case, the
peripheral ridge 3 on the ridged plate 2b has its top end joined to
the flat surface of the peripheral edge portion of the flat plate
2a, with the top end of the central ridge 4 joined to the flat
surface of the central portion of the flat plate 2a and with the
top ends of the channel dividing ridges 5 joined to the
corresponding flat surface portions of the flat plate 2a, whereby a
flat tube 12 is provided wherein a plurality of U-shaped divided
refrigerant passageways 7 are formed in a refrigerant channel
8.
[0163] Although not shown, the evaporator 1 of the third embodiment
of the invention wherein the upper and lower headers 57, 58 are
provided may comprise the pair of front and rear header members 41,
42 each in the form of a rectangular pipe and shown in FIGS. 11 and
12, in place of the spectacle-shaped upper and lower header members
51, 52 shown in FIGS. 16 and 17.
[0164] The evaporator thus modified will be referred to a fourth
embodiment of the invention. The evaporator 1 according to the
fourth embodiment of the invention will be described using
reference numerals of FIGS. 11 and 12. Each of plates 2 in pairs
has straight side edge ridges 33, 33 provided on one side of the
plate along opposite side edges thereof and a central ridge 34
provided on the same side of the plate at the center of the width
thereof and having bifurcated upper and lower ends 34a, 34a, the
ridges being formed by forging or cutting, each plate 2 having
front and rear straight channel recess portions 36a, 36a formed
inwardly of the side edge ridges on opposite sides of the central
ridge 34, each plate 2 having a flat surface on the other side
thereof, each of the pairs of plates being fitted together with
their front and rear channel recess portions 36a, 36b opposed to
each other to join the opposed straight side edge ridges 33, 33 to
each other end-to-end and the opposed central ridges 34, 34
including the bifurcated upper and lower ends 34a, 34a to each
other end-to-end and to thereby form a flat tube 32 having
bifurcated open upper and lower ends and front and rear straight
fluid channels 38, 38 inside thereof, an upper and a lower pair of
front and rear header members 41, 42 being each in the form of a
pipe having a rectangular cross section, each of the header members
41, 42 having slits 44, 44 formed in an upper wall 47 or a lower
wall thereof 43 and arranged at a predetermined spacing, a
plurality of flat tubes 32 being arranged in parallel by inserting
the bifurcated upper or lower ends thereof into the respective
slits 44, 44 in the header members 41, 42 to join the flat tubes to
the header members and to provide an upper and a lower pair of
front and rear headers in communication with the bifurcated upper
and lower ends of the flat tubes 32 respectively. At this time, the
rear wall 46 and the front wall 45 of the respective juxtaposed
front and rear header members 41, 42 are fitted as joined together
into U-shaped notches 37, 37 in the upper ends of the opposed
plates 2, 2 of each flat tube 32.
[0165] Described below are modifications of the evaporator 1 of the
third embodiment of the invention wherein the upper and lower
headers 57, 58 are provided by the spectacle-shaped upper and lower
header members 51, 52 and the evaporator 1 of the fourth embodiment
of the invention wherein the upper and lower headers are provided
by pairs of front and rear header members 41, 42 in the form of
rectangular pipes.
[0166] Like the embodiment shown in FIGS. 18 and 19, usable for a
first modification are plates 2, 2a, 2b each having formed in
respective front and rear refrigerant channel recess portions 6a,
6b thereof many front and rear channel dividing ridges 5a, 5b
having a height twice the depth of the recess portions 6a, 6b.
These ridges 5a, 5b are so provided as to form parallel divided
independent refrigerant passageways 7 in a refrigerant channel 8 in
a flat tube 12 when each of pairs of plates 2a, 2b are fitted
together face-to-face. In this case, the channel dividing ridges
5a, 5b of each of the plates 2a, 2b have their top ends joined to
the bottom wall flat surface of recess portions 6a, 6b of the other
plate 2a or 2b opposed thereto.
[0167] Like the embodiment shown in FIGS. 20 and 21, two kinds of
plates 2a, 2b are usable for a second modification. These plates
2a, 2b are different in the arrangement of straight channel
dividing ridges 5a, 5b which are provided in refrigerant channel
recesses 6, 6 and which have a height twice the depth of the
recesses 6, 6. In this case, the straight channel dividing ridges
5a, 5b on each of the plates 2a, 2b have their top ends joined to
the bottom wall flat surface of recess portion of the other plate
2a or 2b opposed thereto.
[0168] As is the case with the embodiment shown in FIGS. 22 and 23,
usable in a third modification are plates 2 which have a
multiplicity of channel dividing straight ridges 5 formed only in
the rear half of the refrigerant channel recess 6. The front half
of the recess 6 has no ridges whatever and is flat-surfaced. In
this case, the straight ridges 5 on one plate 2 have their top ends
joined to the bottom wall flat surface of the recess 6 of the other
plate 2 opposed thereto.
[0169] As in the case of the flat tube shown in FIG. 24, usable in
a fourth modification in combination with a ridged plate 2b is a
flat plate 2a having the same contour as the plate 2b. In this
case, the side edge ridges 3, 33 on the ridged plate 2b have their
top ends joined to the flat surface of the side edge portions of
the flat plate 2a, with the top end of the central ridge 4, 34
joined to the flat surface of the central portion of the flat plate
2a and with the top ends of the channel dividing straight ridges 5
joined to the corresponding flat surface portions of the flat plate
2a, whereby a flat tube 12, 32 is provided which has front and rear
straight refrigerant channel 8, 38 formed in the tube and a
plurality of divided refrigerant passageways 7 formed in the
refrigerant channel 8, 38.
[0170] Although the heat exchanger 1 of the present invention has
been described with reference to embodiments for use as evaporators
for motor vehicle air conditioners, the present invention can be
applied also to heat changers for use in motor vehicles or in
industries, such as evaporators, condensers, oil coolers,
intercoolers, heater cores, etc.
[0171] In the case where the heat exchanger 1 of the invention is
to be used, for example, as a heater heat exchanger for heating
systems, efficient heat exchange is available since the entire
width of the channel for the fluid is equal to the contact width of
the radiator fin 24. Furthermore, the internal fluid can be passed
in a counterflow relation with air. This results in an increased
temperature efficiency to achieve higher heat exchanger
effectiveness and realize a compacted device.
* * * * *