Heat exchange – Radiator core type – Deformed sheet forms passages between side-by-side tube means
Reexamination Certificate
2001-09-21
2003-04-08
Flanigan, Allen (Department: 3743)
Heat exchange
Radiator core type
Deformed sheet forms passages between side-by-side tube means
C165S152000, C165S174000
Reexamination Certificate
active
06543528
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat exchanger which is used for an air conditioner.
2. Description of the Related Art
FIGS. 7
to
14
show examples of structures of heat exchangers which are used as evaporators for vehicular air conditioners and the like. The heat exchangers shown in these figures are called drawn-cup type heat exchangers, and each air conditioner is constructed by alternately overlaying plate shaped refrigerant passage portions and corrugated plate shaped cooling fins.
In
FIGS. 7 and 8
, reference numeral
11
denotes the refrigerant flow portions and reference numeral
12
denotes the cooling fins. The refrigerant flow portion
11
is obtained by overlaying substantially rectangular flat plates
13
and
14
which are formed by drawing, and brazing at the outer peripheral portions and the central portions thereof. A refrigerant inlet
15
and a refrigerant outlet
16
are provided side by side at the lower end part of the refrigerant flow portion
11
, and an inverted U-shaped refrigerant flow path R which extends upwardly from the refrigerant inlet
15
and turns downwards at the top of the refrigerant flow portion
11
toward the refrigerant outlet
16
, is formed within the refrigerant flow portion
11
.
A plurality of dimples
17
are formed in the refrigerant flow portion
11
by denting the flat plates
13
and
14
which form the refrigerant flow path R from the outside, and these dimples
17
form a plurality of bulged portions
18
in the refrigerant flow path R. Furthermore, the left end of the laminated refrigerant flow portions
11
and cooling fins
12
are covered by a side plate
19
. Hereinafter, the left end of each figure is referred to as the “proximal end” and the right end of each Figure is referred to “distal end”.
The refrigerant inlet
15
is composed of opening portions
13
a
and
14
a
formed in the flat plates
13
and
14
, and the refrigerant inlets
15
of the respective refrigerant flow portions
11
are directly overlaid with no intervening cooling fin
12
, so that a continuous space Sa is formed. Similarly, the refrigerant outlet
16
is composed of opening portions
13
a
and
14
a
formed in the flat plates
13
and
14
, and the refrigerant outlets
16
of the respective refrigerant flow portions
11
are directly overlaid with no intervening cooling fins
12
, so that a continuous space Sb is formed. The proximal end of the space Sa is connected with a refrigerant inlet pipe
20
which extends from the central part of the height of the heat exchanger, and the proximal end of the space Sb is connected with a refrigerant outlet pipe
21
. Furthermore, the distal end of each space Sa, Sb is closed by a cover which is not shown in Figures.
In this heat exchanger, refrigerant which flows into the space Sa through the refrigerant inlet pipe
20
is distributed to each of the refrigerant flow paths R, undergoes heat exchange while it passes through the refrigerant flow paths R, and then is collected at the space Sb and exits from the refrigerant outlet pipe
21
.
The heat exchanger shown in
FIGS. 9
to
11
provides the refrigerant inlet
15
and the refrigerant outlet
16
at the upper end part of the refrigerant flow portion
11
, and a U-shaped refrigerant flow path R which extends downwards from the refrigerant inlet
15
and turns upwards at the bottom of the refrigerant flow portion
11
towards the refrigerant outlet
16
is formed within the refrigerant flow portion
11
. Furthermore, in this air conditioner, the bulged portions
18
are not provided, and a corrugated inner fin
18
a
is sandwiched between each of the flat plates
13
and
14
. In addition, the proximal end of the space Sa is connected with the refrigerant inlet pipe
20
via a header
22
, and the distal end of the space Sb is connected with the refrigerant outlet pipe
21
via a header
23
.
In this heat exchanger, refrigerant which flows into the space Sa from the refrigerant inlet pipe
20
through the header
22
is distributed to each of the refrigerant flow paths R, undergoes heat exchange while passing through the refrigerant flow path R, and then is collected at the space Sb and exists from the refrigerant outlet pipe
21
.
The heat exchanger shown in
FIGS. 12
to
14
further provides an opening
24
which opens adjacent to each refrigerant inlet
15
and refrigerant outlet
16
, and the openings
24
of the refrigerant flow portions
11
are overlaid with no intervening cooling fins
12
so that a continuous space (forward flow path) Sc is formed. Further, the space Sa is divided into two spaces Sa-
1
and Sa-
2
in the longitudinal direction by a partitioning wall
25
. Furthermore, a cover
26
is fixed on the distal end of the heat exchanger, so that a turning portion
27
which connects the distal ends of spaces Sc and Sa-
1
is formed by the cover
26
. In addition, the proximal end of the space Sc is connected with the refrigerant inlet pipe
20
and the proximal end of the space Sa is connected with the refrigerant outlet pipe
21
, and both ends of the space Sb are closed by covers
28
.
In this heat exchanger, the flow of the refrigerant which flows into the space Sc through the refrigerant inlet pipe
20
is turned at the turning portion
27
and flows into the space Sa-
1
and is distributed to the refrigerant flow portions
11
at the distal end side of the heat exchanger. The refrigerant undergoes heat exchange while it passes through each of the refrigerant flow paths R, and is collected at the space Sb. The refrigerant is further distributed to the refrigerant flow portions
11
at the proximal end side of the heat exchanger and passes through each refrigerant flow path R, and is collected at the space Sa-
2
, and then, the refrigerant exists from the refrigerant outlet pipe
21
.
However, when the refrigerant inlet pipe
20
has a 90 degree curve adjacent to the space Sa as denoted by symbol A in
FIG. 7
for example, the flow of the refrigerant is slowed down due to the curve, and therefore, the refrigerant may not reach the innermost regions (the distal end part) of the space Sa, and the refrigerant may not flow to the distal end part of the space Sa. As a result, the refrigerant may not be uniformly distributed throughout the respective refrigerant flow paths R, and consequently, the problem that heat exchange is not sufficient at the refrigerant flow paths R at the distal end part may occur.
Furthermore, the heat exchangers as described above are manufactured by braze welding. For example, in the heat exchanger shown in
FIGS. 10 and 11
, the refrigerant flow portion
11
is constructed by brazing the flat plates
13
and
14
at flange portions
13
c
and
14
c
which are provided on the outer peripheral portions thereof as shown in FIG.
11
. In addition, adjacent refrigerant inlets
15
(or refrigerant outlets
16
) are fastened by brazing a flange-shaped side wall
13
d
which is formed at each opening portion
13
a
(or
14
b
) and a flange-shaped side wall
14
d
which is formed at adjacent opening portion
14
a
(or
13
b
). However, in the latter case, the fastening positions of the refrigerant inlets
15
or refrigerant outlets
16
protrude into the space Sa or Sb and give rise to resistance to the flow of fluid (refrigerant) in the space Sa or Sb. As a result, the pressure loss of the fluid which passes the space Sa or Sb caused by the resistance increases to a significant level, and the heat exchange capacity of the heat exchanger decreases.
Moreover, in recent years, the cooling fins
12
and flat plates
13
,
14
have become thinner, in compliance with the demand for reducing the weight and size of the heat exchanger. However, in case of the heat exchanger as shown in
FIGS. 12
to
14
, it is difficult to reduce the thickness of the turning portion
27
which receives the pressure of the flow of the refrigerant without reducing its strength.
The present invention was made in consideration of the above-mentioned circumstances, and a first object
Anai Yujiro
Saito Katsuhiro
Suzuki Kazuhiro
Watanabe Yoshinori
Yoshikoshi Akira
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