U.S. patent application number 09/847344 was filed with the patent office on 2003-01-16 for plate type heat exchanger.
Invention is credited to Hirabayashi, Yoshinao, Ikezaki, Yasuo, Mori, Kikuichi, Sugiyama, Kazunori.
Application Number | 20030010483 09/847344 |
Document ID | / |
Family ID | 25300386 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030010483 |
Kind Code |
A1 |
Ikezaki, Yasuo ; et
al. |
January 16, 2003 |
Plate type heat exchanger
Abstract
A plate heat exchanger for use as an evaporator in a
refrigerator including a compressor, a condenser, an expansion
valve and the evaporator which cooperate to perform a refrigeration
cycle. The plate heat exchanger comprises a plurality of plates
stacked on each other to define chambers of a refrigerant and
chambers of a medium to be cooled, a refrigerant introduction
passage means extending through the plates and provided with
orifices for delivering the refrigerant from the refrigerant
introduction passage means to the refrigerant chambers, and a
refrigerant stirring member for stirring the refrigerant supplied
into the refrigerant introduction passage means in the form of a
wet steam to make the refrigerant uniform. In both of the case
where the stirring member is provided and the case where it is not
provided, a uniform refrigerant in the heat exchanger will be
attained by providing a refrigerant inlet pipe at a lower part of
one side of the heat exchanger thereof in which an inlet/outlet
port for a medium to be cooled is provided and by providing a
refrigerant outlet pipe at an upper part of the other side of the
heat exchanger opposite to the above-noted one side thereby making
the refrigerant flow in the heat exchanger smooth.
Inventors: |
Ikezaki, Yasuo; (Kanagawa,
JP) ; Hirabayashi, Yoshinao; (Kanagawa, JP) ;
Mori, Kikuichi; (Chiba, JP) ; Sugiyama, Kazunori;
(Shizouka, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
25300386 |
Appl. No.: |
09/847344 |
Filed: |
July 13, 2001 |
Current U.S.
Class: |
165/174 ;
165/167 |
Current CPC
Class: |
F28F 3/083 20130101;
F28D 9/005 20130101; F28F 9/0273 20130101 |
Class at
Publication: |
165/174 ;
165/167 |
International
Class: |
F28F 003/08; F28F
009/02 |
Claims
What is claimed is:
1. A plate heat exchanger for use as an evaporator in a
refrigerator comprising a compressor, a condenser, and the
evaporator for performing the refrigeration cycle, said plate heat
exchanger comprising: a plurality of plates stacked on each other
to define chambers of a refrigerant and chambers of a medium to be
cooled; a refrigerant introduction passage means extending through
said plates and provided with orifices for delivering the
refrigerant from the refrigerant introduction passage means to the
refrigerant chambers; and a refrigerant stirring member for
stirring the refrigerant supplied into the refrigerant introduction
passage means in the form of a wet steam.
2. A plate heat exchanger as set forth in claim 1, in which said
refrigerant stirring member is a cylindrical member provided in
said refrigerant introduction passage and extending in the
longitudinal direction of the refrigerant introduction passage
means, the cylindrical member having a proximal end for receiving
the refrigerant in the form of a wet steam, a distal closed end,
and a plurality of holes formed through the cylindrical wall
thereof between the proximal end and the distal closed end so as to
distribute the refrigerant into the refrigerant introduction
passage means through the holes thereby stirring the refrigerant in
the refrigerant introduction passage means.
3. A plate heat exchanger as set forth in claim 2, in which a
number of the holes formed in the cylindrical wall of the
refrigerant stirring member gradually decreases in a direction from
the proximal end towards the distal closed end of the refrigerant
stirring member.
4. A plate heat exchanger as set forth in claim 2, in which the
opening area of the holes formed in the cylindrical wall of the
refrigerant stirring member gradually decreases in a direction from
the proximal end towards the distal end of the refrigerant stirring
member.
5. A plate heat exchanger as set forth in claim 1, in which said
refrigerant stirring member is of a screw type and provided in the
refrigerant introduction passage means so that the refrigerant
passes through the screw type refrigerant stirring member is
subject to a swirling motion.
6. A plate heat exchanger used as an evaporator in a refrigerator
comprising a compressor, a condenser, and the evaporator for
performing a refrigeration cycle, said plate heat exchanger
comprising: a plurality of plates stacked on each other to define
refrigerant chambers for a refrigerant and medium chambers for a
medium to be cooled, the plates extending in a vertical direction;
a refrigerant introduction passage means horizontally extending
through lower portions of said plates and provided with orifices
for delivering the refrigerant from the refrigerant introduction
passage means into the refrigerant chambers; a refrigerant inlet
pipe provided on one side of the heat exchanger at a lower part
thereof to introduce the refrigerant in the form of a wet steam
into said refrigerant introduction passage means; and, a
refrigerant outlet pipe provided at an upper part of the other side
of the heat exchanger opposite to said one side to discharge the
refrigerant passed through the refrigerant chambers outside the
heat exchanger.
7. A plate heat exchanger as set forth in claim 6, in which an
medium inlet pipe is provided on the side on which said refrigerant
inlet pipe is provided for introducing a medium to be cooled into
said medium chambers and a medium outlet pipe is provided on the
side on which said refrigerant inlet pipe is provided for
discharging the medium from said medium chambers.
8. A plate heat exchanger as set forth in claim 6, in which an
additional refrigerant outlet pipe is provided at an upper part of
said one side of said heat exchanger.
9. A plate heat exchanger as set forth in claim 7, in which an
additional refrigerant outlet pipe is provided at an upper part of
said one side of said heat exchanger.
10. A plate heat exchanger used as an evaporator or a condenser in
a refrigerator comprising a compressor, the condenser, and the
evaporator for performing a refrigeration cycle, said plate heat
exchanger comprising: horizontal inlet and outlet passage means for
refrigerant, the passage means being provided with vertical holes
fluidly communicating the insides of the passage means with
refrigerant chambers; horizontal inlet and outlet passage means for
water or brine, the passage means being provided with vertical
holes fluidly communicating the insides of the passage means with
water or brine chambers; sealing rings for sealing said refrigerant
inlet and outlet passage means from said water or brine chambers,
said sealing ring being provided on its each side with a groove
which is spaced away from the refrigerant in said refrigerant inlet
and outlet passage means and from the water or brine in said water
or brine chambers, said each side being engaged with corresponding
adjacent one of the plates of said plate heat exchanger, said
sealing ring being further provided with a passage fluidly
connecting the grooves formed on the opposite sides of the sealing
ring; and sealing rings for sealing said water or brine inlet and
outlet passage means from said refrigerant chambers, said sealing
ring being provided on its each side with a groove which is spaced
away from the water in said water or brine inlet and outlet passage
means and from the refrigerant in said refrigerant chambers, said
each side being engaged with corresponding adjacent one of the
plates of said plate heat exchanger, said sealing ring being
further provided with a passage fluidly connecting the grooves
formed on the opposite sides of the sealing ring; the plates of
said heat exchanger being provided with through holes each fluidly
connecting said grooves of said sealing rings which are positioned
on and engaged with the opposite sides of the plate having the hole
so that said holes of said plates, said grooves and passages of
said sealing rings cooperate to define horizontal passages
extending and finally leading to the atmosphere.
11. A plate heat exchanger as set forth in claim 10 in which said
horizontal passages leading to the atmosphere are provided with
sealing members for preventing moisture in the atmosphere from
entering into the plate heat exchanger.
12. A refrigerator comprising a compressor, a condenser, and an
evaporator for performing a refrigeration cycle, said refrigerator
employing a plate heat exchanger as the condenser or the
evaporator, said plate heat exchanger comprising: horizontal inlet
and outlet passage means for refrigerant, the passage means being
provided with vertical holes fluidly communicating the insides of
the passage means with refrigerant chambers; horizontal inlet and
outlet passage means for water or brine, the passage means being
provided with vertical holes fluidly communicating the insides of
the passage means with water or brine chambers; sealing rings for
sealing said refrigerant inlet and outlet passage means from said
water or brine chambers, said sealing ring being provided on its
each side with a groove which is spaced away from the refrigerant
in said refrigerant inlet and outlet passage means and from the
water or brine in said water or brine chambers, said each side
being engaged with corresponding adjacent one of the plates of said
plate heat exchanger, said sealing ring being further provided with
a passage fluidly connecting the grooves formed on the opposite
sides of the sealing ring; and sealing rings for sealing said water
or brine inlet and outlet passage means from said refrigerant
chambers, said sealing ring being provided on its each side with a
groove which is spaced away from the water in said water or brine
inlet and outlet passage means and from the refrigerant in said
refrigerant chambers, said each side being engaged with
corresponding adjacent one of the plates of said plate heat
exchanger, said sealing ring being further provided with a passage
fluidly connecting the grooves formed on the opposite sides of the
sealing ring; the plates of said heat exchanger being provided with
through holes each fluidly connecting said grooves of said sealing
rings which are positioned on and engaged with the opposite sides
of the plate having the hole so that said holes of said plates,
said grooves and passages of said sealing rings cooperate to define
horizontal passages extending and finally leading to the
atmosphere.
13. A plate heat exchanger as set forth in claim 12 in which said
horizontal passages leading to the atmosphere are provided with
sealing members for preventing moisture in the atmosphere from
entering into the plate heat exchanger.
14. A plate heat exchanger comprising; a plurality plates stacked
on each other so that the plates constitute a series of sets of two
pairs of adjacent plates including a first pair of adjacent plates
defining a first fluid chamber and a second pair of adjacent plates
defines a second fluid chamber; first openings provided in said
plates which are aligned with each other; second openings provided
in said plates which are aligned with each other; first sealing
rings each provided in said first fluid chamber in such a manner
that the first sealing ring is aligned with said first openings and
sealingly engages with the surfaces of the adjacent plates defining
the first fluid chamber to allow a fluid in one of said second
fluid chambers which are positioned on the opposite sides of the
first fluid chamber to flow into the other of said second fluid
chambers while preventing the fluid from entering into the first
fluid chamber; second sealing rings each provided in said second
fluid chamber in such a manner that the second sealing ring is
aligned with said second openings and sealingly engages with the
surfaces of the adjacent plates defining the second chamber to
allow a fluid in one of said first fluid chambers which are
positioned on the opposite sides of the second fluid chamber to
flow into the other of said first fluid chambers while preventing
the fluid from entering into the second fluid chamber; said first
and second sealing rings being provided with annular grooves on
their opposite sides which are sealingly engaged with said surfaces
of said plates and encircle said first and second openings,
respectively, in such a manner that said annular grooves are spaced
radially outwardly away from said openings, each of said first and
second sealing rings being further provided with a passage for
connecting said annular grooves provided on the opposite sides
thereof; a first conduit extending across each of said first fluid
chambers to fluidly connect said annular grooves formed in the
surfaces of said second sealing rings provided in said second fluid
chambers positioned on the opposite sides of the first fluid
chamber provided with the first conduit; and a second conduit
extending across each of said second fluid chamber to fluidly
connect said annular grooves formed in the surfaces of said first
sealing rings provided in said first fluid chambers positioned on
the opposite sides of the second fluid chamber provided with said
second conduit; in which in the case that the fluid passing through
said first sealing ring leaks through the interface between said
first sealing ring and the surface of said plate engaged with said
first sealing ring, the leaking liquid flows into said annular
groove formed in the surface of the first sealing ring engaging
with the surface of the plate and exits the heat exchanger through
a passage defined by said annular grooves and passages connecting
the annular grooves formed in said first sealing rings and said
second conduits; and in the case that the fluid passing through
said second sealing ring leaks through the interface between said
second sealing ring and the surface of said plate engaged with said
second sealing ring, the leaking liquid flows into said annular
groove formed in the surface of the second sealing ring engaging
with the surface of the plate and exits the heat exchanger through
a passage defined by said annular grooves and passages connecting
the annular grooves formed in said second sealing rings and said
first conduits.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a plate heat exchanger and,
in particular, to a plate heat exchanger for use as an evaporator
in a refrigerator which includes a compressor, a condenser, an
expansion valve and the evaporator which cooperate to perform a
refrigeration cycle.
[0003] 2. Prior Art
[0004] A prior art plate heat exchanger will be explained with
reference to FIGS. 5a and 5b.
[0005] FIG. 5a is a schematic front view of a prior art plate heat
exchanger which, as shown, includes a refrigerant inlet pipe 1, a
refrigerant outlet pipe 6, a water (or brine) inlet pipe 10 and a
water (or brine) outlet pine 16.
[0006] FIG. 5b is a cross-sectional view taken along a line A-A in
FIG. 5a. As shown, wet steam of a refrigerant (i.e., a combination
of a gaseous refrigerant and a liquid refrigerant) which is
introduced into the heat exchanger through the refrigerant inlet
pipe 1, flows through a refrigerant introduction passage 2 and
orifices 3 into refrigerant chambers 4 whereby the refrigerant is
subject to heat exchange with water (or brine) in water (or brine)
chambers 7 via plates 7' which form a partition between adjacent
refrigerant chamber 4 and water chamber 7, and the refrigerant then
flows into a refrigerant outlet passage 5 and finally exits the
system through the refrigerant outlet pipe 6.
[0007] However, the prior plate heat exchanger suffers from the
following problems.
[0008] The orifices 3 are arranged at predetermined intervals in a
direction of the refrigerant introduction passage 2 in such a
manner that each orifice 3 fluidly communicates the distribution
passage 2 with one of corresponding refrigerant chambers 4. Thus,
if the number of refrigerant chambers 4 is increased thereby
causing the refrigerant introduction passage to become long, less
gaseous refrigerant reaches the distal end of the refrigerant
introduction passage since the gaseous refrigerant has a low
specific gravity as compared with that of the liquid refrigerant.
Consequently, the closer to the proximal end of the refrigerant
introduction passage 2 the refrigerant chambers are, the lower is
the ratio of a supplied fluid refrigerant to the gaseous
refrigerant. Since the gaseous refrigerant emits heat as a function
of its sensible heat, when a ratio of supplied fluid to gaseous
refrigerant becomes low, a ratio of heat exchange effected on the
basis of a latent heat of the fluid refrigerant in the refrigerant
chambers near the proximal end of the refrigerant introduction
passage 2 decreases, and the cooling capacity of the refrigerant
chambers becomes insufficient. This leads to a decrease in heat
transfer efficiency, cooling capacity, and COP of the heat
exchanger decreases.
[0009] FIG. 6a is a front view of another type of a prior art plate
heat exchanger and FIG. 6b is a side elevation view of the heat
exchanger. As shown, the heat exchanger includes water (or brine)
inlet/outlet ports 21, 22, a liquid refrigerant inlet/outlet port
23, and a gaseous refrigerant inlet/outlet port 24. The heat
exchanger comprises a plurality of stacked plates and the spaces
between them define either water (or brine) or refrigerant
chambers. FIG. 7a shows a side of a plate constituting the heat
exchanger which defines a water (or brine) chamber 29, and FIG. 7b
shows a side of the plate which defines a refrigerant chamber 33.
The plate includes a gaseous refrigerant inlet/outlet passage 25, a
gasket 26, a space 27, a gasket 28, a liquid refrigerant
inlet/outlet passage 30, and a water (or brine) inlet/outlet
passage 31, 32. When the heat exchanger is used as a condenser, a
gaseous refrigerant supplied through the gaseous refrigerant
inlet/outlet port 24 is subject to heat exchange with a water (or
brine) to form a liquid refrigerant and, then exits through the
liquid refrigerant inlet/outlet port 23. The water supplied through
the water (or brine) inlet/outlet port 22 is subjected to heat
exchange with the refrigerant and, thereafter, exits the heat
exchanger through the water inlet/outlet port 21 with its
temperature having been raised by heat transferred from the
refrigerant. Further, when used as a cooling device, the
refrigerant supplied through the refrigerant inlet/outlet port 13
in the form of a wet steam is subjected to heat exchange with the
water (or brine) to become a gaseous refrigerant and, then, exits
the heat exchanger through the refrigerant inlet/outlet port 22.
The water (or brine) subjected to the heat exchange with the
refrigerant is deprived of its heat and, thus cooled, exits through
the water inlet/outlet port. In the heat exchanger of this type, if
the refrigerant leaks, it will flow outside the heat exchanger in
the following manner. If the refrigerant leaks from the refrigerant
passage 25 and/or 30 shown in FIG. 7a, the leaking refrigerant will
enter the space 27 which is in communication with the atmosphere
and, thus, there is no danger of the refrigerant contaminating
water (or brine) in the water (or brine) chamber 29. Further, if
the refrigerant leaks from the refrigerant chamber 33 shown in FIG.
7b, the leaking refrigerant will enter the space 27 which is in
communication with the atmosphere and, consequently, the leaking
refrigerant will diffuse without entering the water passage 31 or
32 through the gaskets 26 or 36, and consequently there is no
danger of contamination of the water (or brine) by the leaking
refrigerant.
[0010] In contrast, in a prior art plate heat exchanger as shown in
FIG. 8, there is a danger that water will be contaminated by
refrigerant leaking from the refrigerant passage or chamber. FIG. 8
is a front view of the heat exchanger which, as shown in FIG. 6,
includes water inlet/outlet port 31, 32, a liquid refrigerant
inlet/outlet port 33, and a gaseous refrigerant inlet/outlet port
34. As noted from FIGS. 9a and 9b showing the opposite sides of a
plate constituting the heat exchanger, the heat exchanger includes
a gaseous refrigerant inlet/outlet passage 35, a water (or brine)
chamber 39, a liquid refrigerant inlet/outlet passage 40, and water
(or brine) inlet/outlet passages 41, 42, a refrigerant chamber 43,
a sealing ring 44, and a collar 45. Although the mechanism of heat
exchange of this heat exchanger is the same as that of the prior
art heat exchangers of FIGS. 6a-7b, if refrigerant leakage occurs,
water contamination by the refrigerant will also occur, as
explained below with reference to FIGS. 9a and 9b.
[0011] Upon leakage of the refrigerant from the refrigerant passage
35 or 40 shown in FIG. 9a, it passes through an interface existing
between the seal ring 44 and the heat exchanger plate which are
joined together using brazing. Thus, the leaking refrigerant will
directly enter the water (or brine) chamber 39 and contaminates the
water (or brine). If the refrigerant leaks from the refrigerant
chamber 43, except in the case that the refrigerant leaks through
the collar 45, it will pass through the interface existing between
the sealing rings 44 and the heat exchanger plate joined by
brazing, and then directly enter the water passage 41, or 42.
[0012] In the light of the problems involved in the prior art heat
exchanger, the present invention aims to provide a heat exchanger
in which even if refrigerant leaks from a refrigerant passage
and/or chamber, the refrigerant will move to the outside of the
heat exchanger, thereby preventing water in the system being
contaminated by the refrigerant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view showing a system of a
refrigerator equipped with a plate heat exchanger in accordance
with the present invention;
[0014] FIG. 2 is a schematic sectional view of a plate heat
exchanger in accordance with an embodiment of the present
invention;
[0015] FIG. 3a is an enlarged sectional view showing a refrigerant
stirring member of a plate heat exchanger in accordance with
another embodiment of the present invention;
[0016] FIG. 3b is an enlarged side elevation view of another type
of the refrigerant stirring member;
[0017] FIG. 4a is a front view of a refrigerant stirring member in
accordance with a further embodiment;
[0018] FIG. 4b is a side elevation view of the refrigerant stirring
member of FIG. 4a;
[0019] FIG. 5a is a front view of a prior art plate heat
exchanger;
[0020] FIG. 5b is a sectional view taken along a line A-A in FIG.
5a;
[0021] FIG. 6a is a front view of another type of a prior art heat
exchanger;
[0022] FIG. 6b is a side elevation view of the prior art heat
exchanger of FIG. 6a;
[0023] FIG. 7a shows a water (or brine) chamber defining side of a
plate constituting the heat exchanger of FIG. 6a;
[0024] FIG. 7b shows a refrigerant chamber defining side of the
heat exchanger plate of FIG. 7a;
[0025] FIG. 8 is a front view of a different type of a prior art
heat exchanger;
[0026] FIG. 9a shows a water (or brine) chamber defining side of a
plate constituting the heat exchanger of FIG. 8;
[0027] FIG. 9b shows a refrigerant chamber defining side of the
heat exchanger plate of FIG. 9a;
[0028] FIG. 10a is a front view of another type of a heat exchanger
in accordance with the present invention;
[0029] FIG. 10b is a side elevation view taken alone a line A-A in
FIG. 10a;
[0030] FIG. 11a is a front view of a further type of a heat
exchanger in accordance with the present invention;
[0031] FIG. 11b is a side elevation view taken along a line A-A in
FIG. 11a;
[0032] FIG. 12 is a front view of a heat exchanger in accordance
with another embodiment of the present invention;
[0033] FIG. 13 is a front view of a heat exchanger in accordance
with a further embodiment of the present invention;
[0034] FIG. 14 is a diagram showing heat transfer rates of a heat
exchanger of the present invention and the prior art heat
exchangers;
[0035] FIG. 15a is a front view of a heat exchanger in accordance
with an embodiment of the present invention;
[0036] FIG. 15b is a back view of the same heat exchanger
plate;
[0037] FIG. 16a shows a water (or brine) defining side of a heat
exchanger plate of a heat exchanger in accordance with an
embodiment of the present invention;
[0038] FIG. 16b shows a refrigerant chamber defining side of the
heat exchanger plate;
[0039] FIG. 17a is a front view of a sealing ring used in a heat
exchanger of the present invention; and
[0040] FIG. 17b is a sectional view taken along a line A-A in FIG.
17a.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] With reference to the drawings, embodiments of the present
invention will now be explained.
[0042] FIG. 1 shows a system of a refrigerator to be equipped with
a plate heat exchanger in accordance with the present
invention.
[0043] As shown, the refrigerator comprises an evaporator 11, a
compressor 12, a condenser 13 and an expansion valve.
[0044] In the refrigerator, a liquid refrigerant is vaporized in
the evaporator 11, the vaporized refrigerant is then compressed in
the compressor 12 and thereafter cooled by a cooling water 15 in
the condenser 13, to be liquefied, and the liquefied refrigerant is
fed into the evaporator 11 through the expansion valve 14 with the
pressure of the liquefied refrigerant being lowered by means of the
valve, so that the refrigerant deprives the water (or brine)
supplied from an inlet 10 of the evaporator 11 of its heat causing
it to evaporate. The water cooled by heat exchange with the
refrigerant exits the evaporator through an outlet 16.
[0045] FIG. 2 shows schematically a construction of a plate heat
exchanger in accordance with the present invention. As shown, the
heat exchanger includes a refrigerant inlet pipe 1, a refrigerant
introduction passage 2, refrigerant inlet orifices 3, refrigerant
chambers 4, a refrigerant exit passage 5, a refrigerant outlet pipe
6, water chambers 7 and a refrigerant stirring member 8 in the form
of a cylinder. The refrigerant introduction passage 2 is defined by
holes 7" formed in plates 7' defining the refrigerant chambers 4
and the water (or brine) chambers 7 therebetween, which holes are
aligned with each other, and holes of sealing rings 3' provided
between the adjacent plates 7', with the holes being coaxial with
the holes of the plates 7'. The sealing ring 3 is provided with the
orifice 3. The refrigerant exit passage is also defined by holes
formed in the plates 7' which are aligned with each other. The
refrigerant stirring member 8 is connected to the refrigerant inlet
pipe to enable the refrigerant stirring member 8 to receive a
refrigerant and deliver the refrigerant into the refrigerant
introduction passage 2 through a number of small holes 9 formed in
the cylindrical wall of the refrigerant stirring member. Since the
refrigerant is supplied into the refrigerant introduction passage 2
through the small holes, it is subject to turbulence and, as a
result, is stirred.
[0046] FIG. 3a and FIG. 3b show respectively different types of
refrigerant stirring member 8, each of which is provided with the
small holes 9 provided such that the number of the small holes 9
decreases approaching the distal end of the stirring member 8. By
this configuration, an area of opening of the small holes 9
decreases gradually from the proximal end to the distal end of the
stirring member 8. As a result, a relatively large amount of
refrigerant in the form of liquid can be fed into refrigerant
chambers proximate to the refrigerant inlet pipe 1.
[0047] In the heat exchanger described above, a refrigerant in the
form of a wet steam (namely, a mixture of a gaseous refrigerant and
a liquid refrigerant) is supplied through the refrigerant stirring
member 8 into the refrigerant introduction passage 2 to cause
turbulence in the refrigerant in the passage 2, whereby the gaseous
and liquid refrigerants are mixed uniformly. Then, the uniformly
mixed refrigerant is introduced into the refrigerant chambers
evenly and evaporated, thus ensuring that heat exchange effected in
the heat exchanger is uniform across all of the refrigerator
chambers. The vaporized refrigerant is discharged from the
refrigerant outlet pipe 6.
[0048] The refrigerant stirring member 8 may be replaced with
another type of stirring member as shown in FIGS. 4a and 4b, i.e.,
a screw-type refrigerant stirring member 17 which imparts
turbulence to the refrigerant passing through it.
[0049] FIGS. 10a and 10b show a heat exchanger in accordance with
another embodiment of the present invention. As shown, the heat
exchanger includes a refrigerant inlet pipe 1, a refrigerant
introduction passage means 2 provided with orifices (not shown)
corresponding to the orifices 3 in the first embodiment,
refrigerant chambers 4, a refrigerant exit passage 5, a refrigerant
outlet pipe 6, water chambers 7, a water (or brine) inlet pipe 10,
and a water (or brine) outlet pipe 16. This heat exchanger is
characterized in that the refrigerant outlet pipe 6 is provided on
the side of the heat refrigerator opposite to the side provided
with the refrigerant inlet pipe 1.
[0050] In this heat exchanger, the wet steam of refrigerant
introduced therein passes the refrigerant introduction passage 2,
the orifices and the refrigerant chambers 4 and, finally, exits
through the refrigerant outlet pipe 6 provided on the side opposite
to the side provided with the refrigerant inlet pipe 1. In the heat
exchanger as shown in FIG. 5, the refrigerant introduced therein is
turned around to be directed to the refrigerant outlet pipe 6 which
is provided on the same side of the refrigerator as the refrigerant
inlet pipe 1 and, as a result, the gaseous refrigerant and the
liquid refrigerant in the introduced refrigerant are likely to
become separated under the inertia arising as a result of
differences in their specific gravity. In contrast, in the heat
exchanger of FIGS. 10a and 10b, the refrigerant introduced therein
flows smoothly without any turning around of the refrigerant, and
thus separation stated above is unlikely to take place, thereby
improving the rate of heat exchange.
[0051] FIGS. 11a and 11b show a modification of the plate heat
exchanger of FIGS. 10a and 10b in which an additional refrigerant
outlet pipe 6' is provided on the side of the heat exchanger
opposite the side provided with the refrigerant outlet pipe 6,
whereby the flow of the refrigerant flowing into the refrigerant
chambers can be made more smooth to thereby enable the refrigerant
to be distributed evenly in the refrigerant chambers.
[0052] FIG. 12 shows a heat exchanger similar to that shown in FIG.
10a with an exception that the refrigerant inlet and outlet pipes
10 and 16 are provided on the side of the heat exchanger opposite
the side on which, in the heat exchanger of FIG. 10a, the pipes are
provided. FIG. 13 shows a heat exchanger similar to that shown in
FIG. 11a with an exception that the refrigerant inlet and outlet
pipes 10 and 16 are provided on the side of the heat exchanger
opposite the side on which, in the heat exchanger of FIG. 11a,
those pipes are provided.
[0053] FIG. 14 is a graph showing a rate x of heat exchange
effected in the prior art heat exchanger of FIGS. 5a and 5b and
rates y and z of heat exchange effected in the heat exchanger of
the present invention shown in FIGS. 10a and 10b and in FIGS. 11a
and 11b in which graph the x-axis designates a quantity of heat
(W/m.sup.2) and the y-axis designates a heat transfer rate.
(W/m.sup.2K).
[0054] From this graph, it can be seen that by using the heat
exchangers of the present invention a uniform refrigerant can be
supplied into all of the refrigerant chambers evenly, thereby
attaining higher heat transfer rates than those of the prior art
heat exchanger.
[0055] FIG. 15a is a front view of a plate heat exchanger in
accordance with another embodiment of the present invention and
FIG. 15b is a rear view of the same. FIG. 16a shows a refrigerant
chamber defining side of a plate constituting the heat exchanger,
and FIG. 16b shows an opposite side of the plate for defining a
water (or brine) chamber. Further, FIG. 17a is an enlarged front
view of a sealing ring 46 used in the heat exchanger and FIG. 17b
is a sectional view taken along a line A-A in FIG. 17a.
[0056] As is in the heat exchanger shown in FIGS. 8, 9a and 9b, the
heat exchanger of FIGS. 15a-17b comprises water (or brine)
inlet/outlet ports 31 and 32, a liquid refrigerant inlet/outlet
port 33, a gaseous refrigerant inlet/outlet port 34, a gaseous
inlet/outlet passage 35, water (or brine) chambers 39, a
refrigerant inlet/outlet passage 40, water (or brine) inlet/outlet
passages 41, 42, refrigerant chambers 43, sealing rings 46 and
collars 45. The sealing ring 46 includes annular grooves 48
provided on the opposite sides thereof engaged with the surfaces of
the adjacent plates, a passage 49 communicating the annular grooves
provided on the opposite sides of the sealing ring. The plate
includes passages 47 communicating the annular grooves of the
sealing rings engaged with the opposite sides of the plate, so that
refrigerant leaking into one of the annular grooves 48 can be led
to the atmosphere through a passage formed from the passages 47, 49
and the annular grooves 48.
[0057] In the case that the refrigerant leaks from the refrigerant
passages 35 or 40 shown in FIG. 16a, it will pass through the
interface between the sealing ring 46 and the surface of the plate
engaged with the ring 46. The leaking refrigerant will flow into
the annular groove facing the plate surface, and will then flow
through a passage defined by the passages 49 and the annular
grooves 48 of the sealing rings and the passages 47 of the plates
to reach the atmosphere and finally exits the heat exchanger
without any contamination of the water (or brine) by entering the
water (or brine) chambers passages.
* * * * *