U.S. patent application number 14/354120 was filed with the patent office on 2014-11-20 for plate heat exchanger.
This patent application is currently assigned to HISAKA WORKS, LTD.. The applicant listed for this patent is HISAKA WORKS, LTD., Hitachi-GE Nuclear Energy, Ltd.. Invention is credited to Takahisa Funabiki, Isamu Hiwatashi, Kiyoshi Ishihama, Mana Iwaki, Kenji Kusunoki, Seiichi Matsumura.
Application Number | 20140338870 14/354120 |
Document ID | / |
Family ID | 48167796 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140338870 |
Kind Code |
A1 |
Hiwatashi; Isamu ; et
al. |
November 20, 2014 |
PLATE HEAT EXCHANGER
Abstract
Heat transfer plates are stacked, each being provided with a
plurality of passage holes, a flow-path forming gasket is
interposed between peripheries of each adjacent ones of the heat
transfer plates, thereby alternately forming a first flow path to
pass a high-temperature fluid, a second fluid to pass a
low-temperature fluid, and communicating paths to cause the fluids
to flow in and out of the first flow path and the second flow path
on opposite sides of each heat transfer plate, and
communicating-path forming gaskets surrounding the passage holes
are interposed between adjacent ones of the heat transfer plates,
thereby forming a communicating path to cause a fluid to flow in
and out of the first flow path and a communicating path to cause a
fluid to flow in and out the second flow path. Each
communicating-path forming gasket is made up of inner and outer
gasket members arranged in two lines, the inner gasket member
surrounding the passage holes while the outer gasket member
surrounding the inner gasket member.
Inventors: |
Hiwatashi; Isamu;
(Higashi-Osaka-shi, JP) ; Iwaki; Mana;
(Higashi-Osaka-shi, JP) ; Kusunoki; Kenji;
(Higashi-Osaka-shi, JP) ; Ishihama; Kiyoshi;
(Hitachi-shi, JP) ; Matsumura; Seiichi;
(Hitachi-shi, JP) ; Funabiki; Takahisa;
(Hitachi-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HISAKA WORKS, LTD.
Hitachi-GE Nuclear Energy, Ltd. |
Osaka-shi
Hitachi-shi |
|
JP
JP |
|
|
Assignee: |
HISAKA WORKS, LTD.
Osaka-shi
JP
Hitachi-GE Nuclear Energy, Ltd.
Hitachi-shi
JP
|
Family ID: |
48167796 |
Appl. No.: |
14/354120 |
Filed: |
October 23, 2012 |
PCT Filed: |
October 23, 2012 |
PCT NO: |
PCT/JP2012/077362 |
371 Date: |
April 24, 2014 |
Current U.S.
Class: |
165/166 |
Current CPC
Class: |
F28D 9/005 20130101;
F28F 3/08 20130101; F28F 3/10 20130101; F28D 9/0062 20130101; F28F
3/083 20130101; F28F 3/042 20130101; F28F 2275/205 20130101 |
Class at
Publication: |
165/166 |
International
Class: |
F28D 9/00 20060101
F28D009/00; F28F 3/08 20060101 F28F003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2011 |
JP |
2011-233098 |
Claims
1. A plate heat exchanger wherein: a plurality of heat transfer
plates are stacked, each being provided with a plurality of passage
holes; a flow-path forming gasket is interposed between peripheries
of each adjacent ones of the plurality of heat transfer plates,
thereby alternately forming a first flow path adapted to pass a
high-temperature fluid and a second flow path adapted to pass a
low-temperature fluid on opposite sides of each heat transfer
plate; communicating-path forming gaskets surrounding the passage
holes are each interposed between each adjacent ones of the
plurality of heat transfer plates, thereby forming a communicating
path adapted to cause a fluid to flow in and out of the first flow
path and a communicating path adapted to cause a fluid to flow in
and out the second flow path; and each of the communicating-path
forming gaskets is made up of an inner gasket member and an outer
gasket member arranged in two lines, the inner gasket member
surrounding the passage holes while the outer gasket member
surrounding the inner gasket member.
2. The plate heat exchanger according to claim 1, wherein the
communicating-path forming gasket is arranged in two parallel lines
only between the heat transfer plates which form the communicating
path through which the high-temperature fluid flows.)
3. A plate heat exchanger wherein: a plurality of cassette plates
are stacked, each being made up of two heat transfer plates which
are provided with a plurality of passage holes and are permanently
joined on peripheries; a flow-path forming gasket is interposed
between peripheries of each adjacent ones of the plurality of
cassette plates; communicating-path forming gaskets surrounding the
passage holes are each interposed between each adjacent ones of the
plurality of heat transfer cassette plates, thereby alternately
forming a first flow path adapted to pass a high-temperature fluid
and a second flow path adapted to pass a low-temperature fluid
inside each cassette plate and between the cassette plates; wherein
each of the communicating-path forming gaskets is made up of an
inner gasket member and an outer gasket member arranged in two
lines, the inner gasket member surrounding the passage holes while
the outer gasket member surrounding the inner gasket member.
4. The plate heat exchanger according to claim 1, wherein a drain
hole is formed in the heat transfer plates between the inner gasket
member and the outer gasket member of each of the
communicating-path forming gaskets.
5. The plate heat exchanger according to claim 1, wherein a gas
supply hole is formed in the heat transfer plates between the inner
gasket member and the outer gasket member of each of the
communicating-path forming gaskets; and an enclosed space
surrounded by the inner gasket member, the outer gasket member, and
the heat transfer plates is filled with an inert gas.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority to Japanese Patent
Application No. 2011-233098, the disclosure of which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a plate heat exchanger for
exchanging heat between a high-temperature fluid and a
low-temperature fluid. More particularly, the present invention
relates to a plate heat exchanger in which by stacking plural heat
transfer plates and interposing a gasket between peripheries or the
like of each adjacent ones of the heat transfer plates, a flow path
adapted to pass a high-temperature fluid and a flow path adapted to
pass a low-temperature fluid are formed alternately between each
adjacent heat transfer plates.
RELATED ART
[0003] In a plate heat exchanger, plural heat transfer plates 20
are stacked in an upright posture between a plate-shaped
rectangular fixed frame 11 in an upright posture and a plate-shaped
rectangular movable frame 12 in an upright posture as shown in FIG.
8, a first flow path 1 and a second flow path 2 are formed
alternately between the heat transfer plates 20 as shown in FIG. 9,
and a high-temperature fluid H is passed through the first flow
path 1 while a low-temperature fluid C is passed through the second
flow path 2, thereby exchanging heat between the high-temperature
fluid H and low-temperature fluid C.
[0004] Passage holes 11a to 11d serving as inlet ports and outlet
ports for the fluids H and C are provided in four corners of the
fixed frame 11, whereas no passage hole is provided in the movable
frame 12. Also, respective dedicated plates (hereinafter referred
to as a "D plate" and "E plate") 31 and 32 are overlaid on the
fixed frame 11 and the movable frame 12. Passage holes (not
numbered) are provided in four corners of the D plate 31, and a
gasket (hereinafter referred to as a "D gasket") 140 is interposed
between the D plate 31 and the fixed frame 11, surrounding the
passage holes. Note that no passage hole is provided in the E plate
32.
[0005] Also, passage holes 21 to 24 serving as inlet ports and
outlet ports for the fluids H and C are provided in four corners of
each of the heat transfer plates 20, a heat transfer portion (not
numbered) is provided in an intermediate portion of the heat
transfer plate 20, and a gasket 130 is interposed between each
adjacent ones of the heat transfer plates 20, for example, such
that the upper and lower left passage holes 21 and 22 are
communicated with the heat transfer portion while the upper and
lower right passage holes 23 and 24 are closed to the heat transfer
portion, or vice versa.
[0006] The gasket 130 is made up of a flow-path forming gasket 131
configured to surround a periphery (inner side of an outer
peripheral edge) of each heat transfer plate 20 and
communicating-path forming gaskets 132 configured to surround
circumferences of the passage holes 21 to 24, where the flow-path
forming gasket 131 and communicating-path forming gaskets 132 may
be formed either separately or integrally (not shown).
[0007] In the plate heat exchanger, the upper and lower right
communicating-path forming gaskets 132 surround the upper and lower
right passage holes 23 and 24, thereby forming communicating paths
3 isolated from the upper and lower left passage holes 21 and 22 as
well as from the first flow path 1, and the flow-path forming
gasket 131 surrounds the upper and lower left passage holes 21 and
22 as well as the heat transfer portion, thereby forming the first
flow path 1 adapted to pass the high-temperature fluid H.
[0008] Also, in the plate heat exchanger, the upper and lower left
communicating-path forming gaskets 132 surround the upper and lower
left passage holes 21 and 22, thereby forming communicating paths 3
isolated from the upper and lower right passage holes 23 and 24 as
well as from the second flow path 2, and the flow-path forming
gasket 131 surrounds the upper and lower right communicating-path
forming gaskets 132 as well as the heat transfer portion, thereby
forming the second flow path 2 adapted to pass the low-temperature
fluid C therethrough.
[0009] Thus, in FIG. 9, the high-temperature fluid H flows downward
through the first flow path 1 from the upper left passage hole 21
and is discharged through the lower left passage hole 22 while the
low-temperature fluid C flows upward through the second flow path 2
from the lower right passage hole 24 and is discharged through the
upper right passage hole 23, thereby exchanging heat between the
two fluids H and C.
[0010] Also, although not illustrated, Patent Literature 1 and the
like describe a joined plate heat exchanger in which plural
cassette plates constructed by permanently joining peripheries or
other portions of two heat transfer plates by laser welding,
brazing, or the like are stacked in an upright posture and gaskets
are interposed on peripheries of the cassette plates, thereby
forming a first flow path or second flow path in the cassette
plates and forming the second flow path or first flow path between
the cassette plates.
[0011] On the other hand, Patent Literature 2 describes a plate
heat exchanger comprising a flow-path forming gasket and a
communicating-path forming gasket which are integrated into a
single gasket and interposed between heat transfer plates, in which
part of the flow-path forming gasket and part of the
communicating-path forming gasket are arranged side-by-side to
provide double (two) gaskets in a border between a heat transfer
portion and passage holes. In the plate heat exchanger, the double
gaskets are firmly fixed to the heat transfer plates without using
an adhesive and in other part, the gasket is bonded to the heat
transfer plates using an adhesive.
[0012] The double gaskets are interposed between every other pair
of the stacked heat transfer plates (alternately), thereby forming
a flow path configured to communicate the heat transfer portion and
passage holes without double gaskets. Those heat transfer plates
which lack double gaskets are subject to deformation due to
internal pressure, but since the double gaskets are not bonded to
the heat transfer plates with an adhesive, pressure tightness of
the plate heat exchanger is improved.
CITATION LIST
Patent Literature
[0013] Patent Literature 1: JP 2005-106412 A
[0014] Patent Literature 2: JP 9-72686 A
[0015] However, the conventional plate heat exchanger shown above
in FIGS. 8 and 9 have problems such as described below.
[0016] In the plate heat exchanger, as shown in FIG. 9, the
high-temperature fluid H flowing into the first flow path 1 flows
through the communicating path 3 formed by the communicating-path
forming gasket 132 which surrounds the passage hole 21. Since the
communicating-path forming gasket 132 which forms the communicating
path 3 through which the high-temperature fluid H flows has its
inner side (wetted side) placed in contact with the
high-temperature fluid H in a hot, humid environment as shown in
FIG. 10, thermal degradation such as hardening or softening
proceeds with long-term use.
[0017] Also, main component of the communicating-path forming
gasket 132 is polymer (RH). Consequently, when the
communicating-path forming gasket 132 is heated by the
high-temperature fluid H, the polymer reacts with oxygen (O.sub.2)
to generate alkyl radicals (R.). Since an outer side (non-wetted
side) of the flow-path forming gasket 131 contacts the atmosphere,
alkyl radicals (R.) react with oxygen to generate peroxy radicals
(ROO.). The peroxy radicals (ROO.) react with polymer (RH) to
generate peroxide (ROOH). The peroxide (ROOH) is unstable and
readily decomposes itself into alkoxy radicals (RO.) and hydroxyl
radicals (OH.).
[0018] In short, the communicating-path forming gasket 132 which
forms the communicating path 3 through which the high-temperature
fluid H flows has its wetted side placed in contact with the
high-temperature fluid H, and its non-wetted side placed in contact
with the atmosphere. Consequently, high molecules which make up a
main component break down due to oxidative degradation reactions,
increasing the number of radicals and causing breakage of molecular
chains and cross-linking reactions to proceed. This results in a
loss of elasticity intrinsic to rubber. At the same time, since the
communicating-path forming gasket 132 is structurally in a
compressive environment, compression set increases, resulting in
insufficient surface pressure, and cracks develop, resulting in a
rupture. Then, as a result of the rupture, the high-temperature
fluid H may leak from the communicating path 3 into the second flow
path, mixing with the low-temperature fluid C.
[0019] Also, double gaskets are interposed inside the plate heat
exchanger described in Patent Literature 2. However, the
communicating-path forming gasket 132 which forms the communicating
path 3 through which the high-temperature fluid H flows does not
have two lines, and thus oxidative degradation can occur, resulting
in external leakage of the high-temperature fluid H.
[0020] When the high-temperature fluid H is a dangerous chemical
solution, leaking out of the high-temperature fluid H from the
plate heat exchanger may cause secondary accidents. If the gaskets
are replaced a little earlier to prevent secondary accidents, this
will increase running costs. Also, a method is conceivable which
inhibits oxidative degradation and prevents the high-temperature
fluid H from flowing out, by covering the entire plate heat
exchanger with an airtight sheet or the like or inserting rubber or
the like into gaps among outer peripheral portions of the stacked
heat transfer plates, but such a method is not adopted because of
problems in terms of costs and quality.
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0021] Thus, an object of the present invention is to provide a
plate heat exchanger that is less likely to cause degradation of
communicating-path forming gaskets which form a communicating path
through which a high-temperature fluid flows.
Means for Solving Problems
[0022] In a plate heat exchanger according to the present
invention, a plurality of heat transfer plates are stacked, each
being provided with a plurality of passage holes; a flow-path
forming gasket is interposed between peripheries of each adjacent
ones of the plurality of heat transfer plates, thereby alternately
forming a first flow path adapted to pass a high-temperature fluid
and a second fluid adapted to pass a low-temperature fluid on
opposite sides of each heat transfer plate; communicating-path
forming gaskets surrounding the passage holes are each interposed
between each adjacent ones of the plurality of heat transfer
plates, thereby forming a communicating path adapted to cause a
fluid to flow in and out of the first flow path and a communicating
path adapted to cause a fluid to flow in and out the second flow
path; and each of the communicating-path forming gaskets is made up
of an inner gasket member and an outer gasket member arranged in
two lines, the inner gasket member surrounding the passage holes
while the outer gasket member surrounding the inner gasket
member.
[0023] Here, as one aspect of the plate heat exchanger according to
the present invention, the communicating-path forming gasket may be
arranged in two parallel lines only between the heat transfer
plates which form the communicating path through which the
high-temperature fluid flows.
[0024] In a plate heat exchanger according to the present invention
different from the one described above, a plurality of cassette
plates are stacked, each being made up of two heat transfer plates
which are provided with a plurality of passage holes and are
permanently joined on peripheries; a flow-path forming gasket is
interposed between peripheries of each adjacent ones of the
plurality of cassette plates; communicating-path forming gaskets
surrounding the passage holes are each interposed between each
adjacent ones of the plurality of heat transfer plates, thereby
alternately forming a first flow path adapted to pass a
high-temperature fluid and a second flow path adapted to pass a
low-temperature fluid inside each cassette plate and between the
cassette plates, wherein each of the communicating-path forming
gaskets is made up of an inner gasket member and an outer gasket
member arranged in two lines, the inner gasket member surrounding
the passage holes while the outer gasket member surrounding the
inner gasket member.
[0025] Also, as one aspect of the plate heat exchanger according to
the present invention, a configuration can be adopted in which a
drain hole is formed in the heat transfer plates between the inner
gasket member and the outer gasket member of each of the
communicating-path forming gaskets.
[0026] Also, as another aspect of the plate heat exchanger
according to the present invention, a configuration can be adopted
in which a gas supply hole is formed in the heat transfer plates
between the inner gasket member and the outer gasket member of each
of the communicating-path forming gaskets; and an enclosed space
surrounded by the inner gasket member, the outer gasket member, and
the heat transfer plates is filled with an inert gas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic exploded perspective view showing a
plate heat exchanger according to first and second embodiments of
the present invention.
[0028] FIG. 2 is a schematic exploded perspective view showing
principal part of the plate heat exchanger according to the first
and second embodiments of the present invention.
[0029] FIG. 3 is a schematic exploded perspective view showing
principal part of the plate heat exchanger according to a variation
of the first and second embodiments of the present invention.
[0030] FIG. 4 is a perspective view showing the plate heat
exchanger according to the second embodiment of the present
invention.
[0031] FIG. 5 is an enlarged exploded perspective view showing
principal part of the plate heat exchanger according to the second
embodiment of the present invention.
[0032] FIG. 6 is an enlarged sectional view along the line V-V in
FIG. 5, showing principal part of the plate heat exchanger
according to the second embodiment of the present invention.
[0033] FIG. 7 is an enlarged sectional view showing principal part
of the plate heat exchanger according to the third embodiment of
the present invention.
[0034] FIG. 8 is a schematic perspective view showing a
conventional plate heat exchanger.
[0035] FIG. 9 is a schematic exploded perspective view showing the
conventional plate heat exchanger.
[0036] FIG. 10 is an enlarged sectional view of principal part
showing principal part of the conventional plate heat
exchanger.
DESCRIPTION OF EMBODIMENTS
[0037] A plate heat exchanger according to a first embodiment of
the present invention is described below with reference to FIGS. 1
to 3. The same components as conventional components are described
by the same reference numerals as the corresponding conventional
components. In the following description, terms such as upper,
lower, right, and left are exemplary in each embodiment, and,
needless to say, may represent different positions depending on
actual usage.
[0038] As is conventionally the case, the plate heat exchanger
according to the first embodiment is an apparatus in which a first
flow path 1 and a second flow path 2 are formed alternately between
heat transfer plates 20 as shown in FIGS. 1 to 3, a
high-temperature fluid H is passed through the first flow path 1
while a low-temperature fluid C is passed through the second flow
path 2. The first flow paths 1 and the second flow paths 2 are
formed by respective gaskets 30 interposed between the heat
transfer plates 20.
[0039] The gaskets 30 each are made up of a flow-path forming
gasket 31 configured to surround a periphery of each heat transfer
plate 20 and a communicating-path forming gasket 32 configured to
surround circumferences of the passage holes 21 to 24, so that the
flow-path forming gasket 31 and the communicating-path forming
gasket 32 may be formed either integrally (shown in FIGS. 1 and 2)
or separately (shown in FIG. 3). The gasket 30 in which the
flow-path forming gasket 31 and the communicating-path forming
gasket 32 are formed integrally is based on shared use of a border
between a heat transfer portion and the passage holes 21 to 24, as
shown in FIG. 2.
[0040] In the plate heat exchanger according to the first
embodiment, as shown in FIG. 2, the communicating-path forming
gasket (hereinafter, referred to as "double-line gasket") 32
provided with a communicating path 3 through which a
high-temperature fluid H is passed is made up of an inner gasket
member 32a and an outer gasket member 32b arranged in two lines.
Consequently, each heat transfer plate 20 is double-grooved to
correspond to the inner gasket member 32a and the outer gasket
member 32b of the double-line gasket 32.
[0041] The inner gasket member 32a is formed annularly so as to
surround the passage holes 21 and 22. The outer gasket member 32b
is formed in the shape of a modified trapezoid and its border with
the second flow path 2 is shared with the flow-path forming gasket
31.
[0042] As shown in FIG. 3, when the flow-path forming gasket 31 and
the communicating-path forming gasket 32 are formed separately, the
double-line gasket 32 is configured by arranging the annular inner
gasket member 32a and the annular outer gasket member 32b
concentrically in two parallel lines, the inner gasket member 32a
surrounding the passage holes 21 and 22 while the outer gasket
member 32b surrounding the inner gasket member 32a. Therefore, no
part of the outer gasket member 32b is shared with the flow-path
forming gasket 31.
[0043] Thus, the double-line gasket 32 surrounds the upper and
lower left passage holes 21 and 22, thereby forming the
communicating path 3 through which the high-temperature fluid H
flows. The communicating path 3 through which the low-temperature
fluid C flows is formed by the communicating-path forming gasket
132, which is a conventionally-used typical gasket (hereinafter
referred to as a "single-line gasket") 130, surrounding the upper
and lower right passage holes 23 and 24. However, the communicating
path 3 may be formed by the double-line gasket 32 surrounding the
upper and lower right passage holes 23 and 24.
[0044] Then, the first flow path 1 adapted to pass the
high-temperature fluid H is formed by the communicating-path
forming gasket 132, which is a single-line gasket 130, being
interposed between a pair of heat transfer plates 20 such that the
communicating-path forming gasket 132 isolates the upper and lower
right passage holes 23 and 24 and that the flow-path forming gasket
131 surrounds the upper and lower left passage holes 21 and 22, and
the heat transfer portion.
[0045] Note that although not illustrated, the flow-path forming
gasket 131 which forms the first flow path 1 may also be made up of
an inner gasket member and an outer gasket member arranged in two
parallel lines. This can prevent the gasket which forms the first
flow path from oxidative degradation. Furthermore the flow-path
forming gasket 131 which forms the second flow path 2 may be also
made up of an inner gasket member and an outer gasket member
arranged in two parallel lines. This makes it possible to assemble
the first flow path 1 and the second flow path 2 without
distinguishing therebetween.
[0046] As the gasket 30 and the single-line gasket 130 are
interposed between adjacent heat transfer plates 20 alternately,
the high-temperature fluid H flows through the first flow path 1
from the upper left passage hole 21 and is discharged through the
lower left passage hole 22 while the low-temperature fluid C flows
through the second flow path 2 from the lower right passage hole 24
and is discharged through the upper right passage hole 23, thereby
exchanging heat between the high-temperature fluid H and the
low-temperature fluid C.
[0047] In so doing, the high-temperature fluid H flows into the
first flow path 1 by passing through the upper left communicating
path 3. The high-temperature fluid H in the communicating path 3
contacts the inner gasket member 32a of the double-line gasket 32,
but the inner gasket member 32a, whose circumferences are
surrounded by the outer gasket member 32b, does not contact the
atmosphere, and is thus less prone to oxidative degradation
reactions.
[0048] Since the high-temperature fluid H flowing through the lower
left communicating path 3 has been lowered in temperature by
exchanging heat with the low-temperature fluid C, the gasket 32
which forms the lower left communicating path 3 may be configured
to have a single line rather than two lines. Even if the
communicating paths 3 used to communicate the upper and lower right
passage holes 23 and 24 is formed by the communicating-path forming
gasket 132 configured to be a single-line gasket 130, the
communicating paths 3, through which the low-temperature fluid C
flows, do not get so hot as to cause oxidative degradation of the
communicating-path forming gaskets 132.
[0049] Thus, the plate heat exchanger is configured such that the
double-line gaskets 32 will not crack and that the high-temperature
fluid H will not leak from the communicating paths 3.
[0050] Next, a plate heat exchanger according to a second
embodiment of the present invention is described below with
reference to FIGS. 2 to 6. According to the second embodiment, a
drain hole 25 and/or a gas supply hole 26 are provided in the heat
transfer plate 20 sandwiched between the inner gasket member 32a
and the outer gasket member 32b of the double-line gasket 32.
[0051] In order to discharge the high-temperature fluid H leaking
from the inner gasket members 32a of the double-line gaskets 32,
the drain hole 25 is made continuous by the annular gasket 33
interposed between each pair of heat transfer plates 20 where the
first flow path 1 is provided.
[0052] Then, as shown in FIG. 4, a nozzle 13 continuous with each
drain hole 25 is mounted on the fixed frame 11, making it possible
to detect any leakage of the high-temperature fluid H from the
nozzle 13 and hence detect any leakage from the inner gasket
members 32a due to cracks, as shown in FIG. 6.
[0053] FIGS. 5 and 6 also show how the double-line gasket 32 shown
in FIG. 2 is interposed between each pair of the heat transfer
plates 20 and how the communicating hole 21 is surrounded by
double-line D gaskets 41 and 42 interposed between the fixed frame
11 and a D plate 20d, but the plate heat exchanger according to the
second embodiment can use the double-line gasket 32 shown in FIG. 3
as well.
[0054] In either case, the gas supply hole 26 is formed to make the
inner gasket member 32a still less prone to oxidative degradation
reactions. In other words, an inert gas such as nitrogen is
supplied from the gas supply hole 26 to an enclosed space
surrounded by the inner gasket member 32a and the outer gasket
member 32b of the double-line gasket 32 and the two heat transfer
plates 20 so that the inner gasket member 32a does not contact
oxygen at all.
[0055] Regarding the enclosed space, since the first flow paths 1
are placed next to one another via the heat transfer plates 20, by
interposing the annular gasket 33 continuous with the gas supply
hole 26 between each pair of heat transfer plates 20 where the
first flow path 1 is provided, an inert gas is supplied into the
enclosed space through each nozzle 14 mounted on the fixed frame 11
and communicated with the gaskets 33. As shown in FIG. 4, the
nozzles 14 for use to supply the inert gas are mounted on the fixed
frame 11.
[0056] The drain hole 25 and the gas supply hole 26 may be provided
only in the upper left communicating path 3 through which the
high-temperature fluid H flows at a high temperature, but when the
drain hole 25 and the gas supply hole 26 are provided also in the
double-line gasket 32 forming the lower left communicating path 3
through which the high-temperature fluid H flows at a lowered
temperature, the heat transfer plate 20 can be assembled upside
down. Thus, when the drain hole 25 and the gas supply hole 26 are
provided in the upside-down position, the drain hole 25 is formed
to serve as the gas supply hole 26 and the gas supply hole 26 is
formed to serve as the drain hole 25.
[0057] Next, a plate heat exchanger according to a third embodiment
of the present invention is described below with reference to FIG.
7. According to the third embodiment, double-line gaskets 32 are
interposed between plural cassette plates 200 stacked in an upright
posture.
[0058] The cassette plate 200 is constructed by permanently joining
peripheries of two heat transfer plates 20 by laser welding,
brazing, or the like (indicated by black dots in FIG. 7), and the
first flow path 1 adapted to pass the high-temperature fluid H or
the second flow path 2 adapted to pass the low-temperature fluid C
is provided therein.
[0059] Plural cassette plates 200 are stacked, and the second flow
path 2 adapted to pass the low-temperature fluid C or the first
flow path 1 adapted to pass the high-temperature fluid H is
provided between each adjacent ones of the cassette plates 200. The
gaskets 30 are interposed between the peripheries of the stacked
cassette plates 200.
[0060] The gasket 30 is a combination of the flow-path forming
gasket (not shown) interposed in the permanently joined peripheries
of the cassette plate 200 and the double-line gasket 32 forming the
communicating path 3. The double-line gasket 32 is configured by
arranging the annular inner gasket member 32a and the annular outer
gasket member 32b concentrically in two lines, the inner gasket
member 32a surrounding the passage holes 21 and 22 while the outer
gasket member 32b surrounding the inner gasket member 32a. The
outer gasket member 31b is installed inside the permanently joined
portions as illustrated.
[0061] Alternatively, although not illustrated, the outer gasket
member 32b may be installed in a space 201 between the permanently
joined portions and the inner gasket member 32a may be installed
inward from the permanently joined portion (a line on which the
outer gasket member 32b is installed in FIG. 7).
[0062] Since the high-temperature fluid H is passed through the
first flow path 1 in the cassette plate 200, the high-temperature
fluid H also flows through the communicating paths 3. The
communicating paths 3 are formed by the double-line gaskets 32
which surround the passage holes 21 and 22. Although the inner
gasket members 32a of the double-line gaskets 32 are placed in
contact with the high-temperature fluid H, reactions with oxygen in
the atmosphere are inhibited, thereby inhibiting oxidative
degradation.
[0063] Therefore, the plate heat exchanger configured by assembling
the cassette plates 200 is also less prone to early leakage of the
high-temperature fluid H, with settling or subsidence of the
double-line gaskets 32 inhibited, where the settling could be
caused by cracks and aging degradation. The plate heat exchanger
can be configured such that the high-temperature fluid H will not
leak even if the low-temperature fluid C is passed through the
cassette plates 200 and the high-temperature fluid H is passed
between the cassette plates 200.
[0064] Thus, in the plate heat exchanger according to the present
embodiment, the plurality of heat transfer plates 20 are stacked,
each being provided with the plurality of passage holes 21, 22, 23,
and 24; the flow-path forming gasket 31 is interposed between
peripheries of each adjacent ones of the heat transfer plates 20,
thereby alternately forming the first flow path 1 adapted to pass
the high-temperature fluid H and the second fluid 2 adapted to pass
the low-temperature fluid C on opposite sides of each heat transfer
plate 20; the communicating-path forming gaskets 32 surrounding the
passage holes 21, 22, 23, and 24 are interposed between adjacent
ones of the heat transfer plates 20, thereby forming the
communicating path 3 adapted to cause the fluid H to flow in and
out of the first flow path 1 and the communicating path 3 adapted
to cause the fluid C to flow in and out the second flow path 2; and
each of the communicating-path forming gaskets 32 is made up of the
inner gasket member 32a and the outer gasket member 32b arranged in
two lines, the inner gasket member 32a surrounding the passage
holes 21, 22, 23, and 24 while the outer gasket member 32b
surrounding the inner gasket 32a. Therefore, since the
communicating-path forming gaskets 32, each made up of the inner
gasket member 32a and the outer gasket member 32b arranged in two
parallel lines, surround the passage holes 21, 22, 23, and 24,
forming the communicating paths 3, although the inner gasket member
32a is exposed to the high-temperature fluid H, reactions with
oxygen in the atmosphere are inhibited. Therefore, breakage of
molecular chains and cross-linking reactions due to oxidative
degradation reactions do not proceed in the inner gasket member 32a
which maintains sealing and consequently increases in compression
set and cracks are suppressed. Thus, the high-temperature fluid H
flowing through the communicating paths 3 formed by the
communicating-path forming gaskets 32 can be made less prone to
leakage.
[0065] Also, in the plate heat exchanger according to the present
embodiment, the communicating-path forming gasket 32 is arranged in
two parallel lines only between the heat transfer plates 20 which
form the communicating path 3 through which the high-temperature
fluid H flows. Thus, in view of the fact that the
communicating-path forming gasket 32 which forms the communicating
path 3 through which the high-temperature fluid H flows is prone to
degradation due to oxidative degradation reactions, only the
communicating-path forming gasket 32 is configured to have two-line
arrangement and the communicating-path forming gasket 32 which
forms a flow path through which the low-temperature fluid C flows
is configured to have a single-line arrangement.
[0066] Also, in the plate heat exchanger according to the present
embodiment, the plurality of cassette plates 200 are stacked, each
of the cassette plates 200 being made up of two heat transfer
plates 20 which are provided with the plurality of passage holes
21, 22, 23, and 24 and are permanently joined along peripheries;
the flow-path forming gasket 31 is interposed between peripheries
of each adjacent ones of the cassette plates 200; the
communicating-path forming gasket 32 surrounding the passage holes
21, 22, 23, and 24 is interposed between the adjacent heat transfer
plates 200, thereby alternately forming the first flow path 1
adapted to pass the high-temperature fluid H and the second flow
path 2 adapted to pass the low-temperature fluid C inside each
cassette plate 200 and between the cassette plates 200, wherein
each of the communicating-path forming gaskets 32 is made up of an
inner gasket member 32a and an outer gasket member 32b arranged in
two lines, the inner gasket member 32a surrounding the passage
holes while the outer gasket member 32b surrounding the inner
gasket 32a. Since the communicating-path forming gasket 32
interposed between the cassette plates 200 is made up of the inner
gasket member 32a and the outer gasket member 32b arranged in two
lines, when the first flow path 1 adapted to pass the
high-temperature fluid H is provided in the cassette plates 200 the
communicating-path forming gasket 32 is less prone to oxidative
degradation reactions, and consequently progress of gasket
degradation can be suppressed, and leakage of the high-temperature
fluid H from the communicating path 3 can be prevented from being
easily caused.
[0067] Also, in the plate heat exchanger according to the present
embodiment, the drain hole 25 is formed in the heat transfer plate
20 between the inner gasket member 32a and the outer gasket member
32b of the communicating-path forming gasket 32. Since the drain
hole 25 is formed in the heat transfer plate between the inner
gasket member 32a and the outer gasket member 32b, even if the
inner gasket undergoes settling or subsidence due to thermal
degradation or aging degradation, the high-temperature fluid H
leaking from the inner gasket member 32a can be discharged through
the drain hole 25 in the outer gasket member 32b.
[0068] Also, in the plate heat exchanger according to the present
embodiment, the gas supply hole 26 is formed in the heat transfer
plate 20 between the inner gasket member 32a and the outer gasket
member 32b of the communicating-path forming gaskets 32 and an
enclosed space surrounded by the inner gasket member and the heat
transfer plates 20 is filled with an inert gas. Since the enclosed
space surrounded by the inner gasket member 32a, the outer gasket
member 32b, and the heat transfer plates 20 is filled with an inert
gas, it is possible to minimize oxidative degradation reactions of
the inner gasket member 32a by eliminating air in the enclosed
space.
[0069] Note that the present invention is not limited to the first
to third embodiments described above and that various changes can
be made to the embodiments. For example, the plate heat exchanger
described in the third embodiment in which the cassette plates 200
are stacked may be provided with the exhaust hole and the gas
supply hole 26 described in the second embodiment. Also, the
communicating-path forming gasket 30 may be arranged in two lines
only on the upstream side of the first flow path 1 as described in
the first embodiment. Also, the nozzle 13 continuous with the drain
hole 25 and the nozzle 14 continuous with the gas supply hole 26
may be installed on the movable frame 12 rather than on the fixed
frame 11.
REFERENCE SIGNS LIST
[0070] 1 . . . First flow path [0071] 2 . . . Second flow path
[0072] 3 . . . Communicating path [0073] 20 . . . Heat transfer
plate [0074] 21, 22, 23, 24 . . . Passage hole [0075] 25 . . .
Drain hole [0076] 26 . . . Gas supply hole [0077] 30 . . . Gasket
[0078] 31 . . . Flow-path forming gasket [0079] 32 . . .
Communicating-path forming gasket (double-line gasket) [0080] 32a .
. . Inner gasket member [0081] 32b . . . Outer gasket member [0082]
200 . . . Cassette plate [0083] C . . . Low-temperature fluid
[0084] H . . . High-temperature fluid
* * * * *