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(12) EUROPEAN PATENT APPLICATION

(43) Date of publication: 27.10.2010 Bulletin 2010/43

(21) Application number: 10158177.5

(22) Date of filing: 29.03.2010

(51) Int Cl.:F28D 9/00 (2006.01) F28F 3/02 (2006.01)

F28F 27/00 (2006.01)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TRDesignated Extension States: AL BA ME RS

(30) Priority: 20.04.2009 JP 2009101964

(71) Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Kobe-shi,Hyogo 651-8585 (JP)

(72) Inventors: • Mitsuhashi, Kenichiro

Takasago-shi Hyogo 676-8670 (JP)• Terada, Susumu

Takasago-shi Hyogo 676-8670 (JP)• Noishiki, Koji

Takasago-shi Hyogo 676-8670 (JP)

(74) Representative: TBK-PatentBavariaring 4-680336 München (DE)

(54) Plate fin heat exchanger

(57) A plate fin heat exchanger of the present inven-tion includes a heat exchange part including a heat ex-change part main body including layers of plural flow pas-sages, and heat transfer members each of which is dis-posed within each flow passage of the heat exchangepart main body to transfer the heat of fluid flowing in eachof the flow passages to each partition walls opposedacross the flow passage, and sensing parts connectedto both the outsides of the heat exchange part respec-tively. Each of the sensing parts includes plural sealedspaces, and a sensor wall disposed to separate the out-ermost sealed space from the sealed space on the innerside thereof. The plate fin heat exchanger further in-cludes a detection means for detecting damage of thesensor wall of the sensing part. According to such a struc-ture, external leak of the fluid performing the heat ex-change can be prevented while suppressing deteriora-tion of performance or increase in size or weight.

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Description

BACKGROUND OF THE INVENTION

Field of the Intention:

[0001] The present invention relates to a so-calledplate fin heat exchanger which is internally provided withfin plates.

Description of the Related Art:

[0002] As the plate fin heat exchanger (hereinafter alsosimply referred to as "heat exchanger"), the one de-scribed in Japanese Patent Application Laid-Open No.7-167580 is conventionally known. This heat exchangerincludes a heat exchange part including plural flow pas-sages for carrying first fluid and flow passages for carry-ing second fluid alternately arranged within a casing.Concretely, as shown in Figs. 4A and 4B, a heat ex-change part 100 includes a plurality of partition plates102 placed in parallel at intervals; corrugated plate-likefin plates 104 each of which is placed between the par-tition plates 102; and sealing members 106 placed onboth sides of the fin plates 104 in their width direction soas to sandwich them, the sealing members 106 sealingthe space between the partition plates 102 along the finplate 104 to form a flow passage r together with the par-tition plates 102 therein. In order to transfer the heat ofa fluid flowing in the flow passage r with the fin plate 104placed therein to a pair of partition plates 102 with the finplate 104 therebetween, the plate fin 104 connects thepair of partition plates 102 at specific positions arrangedat intervals between one sealing member 106 and theother sealing member 106 (refer to Fig. 4B). In the thus-constituted heat exchange part 100, a number of flowpassages r are arranged in layers.[0003] In this heat exchanger, each of two kinds of flu-ids (e.g., high-temperature fluid and low-temperature flu-id) are alternately flowed in each of plural layers of flowpassages r arranged in the heat exchange part 100 inorder to perform heat exchange between the two kindsof fluids flowing in adjacent flow passages through thepartition plate 102. At that time, the fin plate 104 transfersthe heat of the fluid flowing between the pair of partitionplates 102 with the fin plate 104 therebetween to the pairof partition plates 102, whereby the efficiency of the heatexchange is improved The thus-constituted heat ex-changer is used as heat exchangers for various purposessuch as an air separator which requires compactnesssince it has a relatively simple structure and a high overallheat transfer coefficient.[0004] Protection parts 110 each provided with an in-ternal space r1 are generally disposed on both outsidesof the above-mentioned heat exchange part 100 respec-tively in the arrangement direction of the flow passagesr of the heat exchange part 100 (in the vertical directionin Fig. 4B). The protection part 110 is a member provided

to protect the flow passage r for carrying the fluid fromdamage attributed to a contact of the heat exchange part100 with other members, etc. at the time of the installationor transfer, etc. of the heat exchanger. Namely, even ifthe heat exchange part 100 is contacted with other mem-bers and the outer surface of the heat exchange part 100dents, the dent occurs only within the range of the pro-tection part 110, and therefore the deformation resultingfrom the dent is not generated on the partition plates 102constituting the flow passages r, etc. which are inside theprotection part 110. The protection part 110 has the samestructure as each flow passage r of the heat exchangepart 100.[0005] In the above-mentioned heat exchange part100, since the sealing member 106 generally has higherrigidity than the fin plate 104, and the fin plate 104 gen-erally has more excellent heat transfer performance thanthe sealing member 106, the following property to thermalchange is higher in the fin plate 104 than in the sealingmember 106. Therefore, if the temperature of the fluidflowing in each flow passage r in the heat exchange part100 suddenly changes, the fin plate 104 deforms morelargely than the sealing member 106 in each flow pas-sage r based on this temperature change. Such a differ-ence in the temperature change-based deformationamount between the sealing member 106 and the finplate 104 causes a stress (thermal stress) based on thisdifference in deformation amount in a specific site of theheat exchange part 100. Concretely, although the sealingmember 106 does not expand so much by a sudden tem-perature change of the fluid (e.g., 50 °C /min, etc.), thefin plate 104 is apt to expand more largely than the sealingmember 106. At that time, as shown in Fig. 5, althoughthe space between a pair of partition plates 102 with theflow passage r therebetween is not changed largely inthe vicinity of a site where the highly rigid sealing member106 is disposed, the space is expanded by the expansionof the fin plate 104 in a site distant from the sealing mem-ber 106 or in the width-directional center site of the flowpassage r. Such deformation of the partition plates 102causes the deformation-attributed stress (thermal stress)in a specific site of the partition plates 102. This thermalstress generally generates, upon a sudden change inflow rate or temperature in the heat exchange part 100,due to the difference in the deformation amount basedon the change in temperature or the like of each member,and such thermal stress attributed to the difference indeformation amount of each member is similarly causedin the specific site not only by the change in temperatureor the like of the high-temperature fluid but also by thechange in temperature or the like of the low-temperaturefluid.[0006] In general, since a number of (e.g., several hun-dreds) flow passages r are arranged in layers in the heatexchange part 100, the deformation amount from the in-itial position of the partition plate 102 separating the flowpassages r from each other is increased from the centertoward the outer side (the upper side and lower side in

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Fig. 5) in the arrangement direction of the flow passagesr. This is attributed to that the deformation amount in eachlayer (each flow passage) is added from the center to-ward the outer side as shown in Fig. 5.[0007] Therefore, as in the case where the heat ex-changer is used in a chemical plant, for example, thedeformation is repeated at each time of sudden changein temperature of the fluid performing the heat exchangeor start-stop during the entire period of use, and as aresult, the fatigue based on the thermal stress is accu-mulated most in a specific position of the partition plate102 which receives the largest deformation amount andseparates the protection part 110 from the flow passager on the inside of the protection part 110, whereby theprobability of damage such as hole or cracking in thepartition plate 102 becomes high.[0008] If damage such as hole occurs in the partitionplate 102 at this position, the fluid flowing in the flow pas-sage r flows into the internal space r1 of the protectionpart 110. Since the fluid in high-pressure state flows inthe flow passage r of the heat exchange part 100 in op-eration, continuous outflow of the fluid from the flow pas-sage r into the internal space r1 of the protection part 110can lead to leak of the fluid from the internal space r1 ofthe protection part 110 to the outside of the heat exchang-er due to the gradual increase of pressure within the pro-tection part 110.[0009] Thus, for preventing such leak of the fluid outof the heat exchanger, it has been considered to enhancethe rigidity of the fin plate 104 or to suppress the defor-mation amount of the partition plate 102 between the flowpassages r by inserting a reinforcing member into eachof the flow passages r to suppress the deformationamount of the partition plate 102 and thereby the accu-mulation of fatigue.[0010] However, when the rigidity of the fin plate 104is enhanced in this way, the heat conductivity of the finplate 104 is reduced, whereby the heat exchange effi-ciency of the heat exchange part 100 is deteriorated, re-sulting in deterioration of performance of the heat ex-changer. The use of the reinforcing member involves aproblem such as increase in size or weight of the device.

SUMMARY OF THE INVENTION

[0011] In view of the above-mentioned problems, thepresent invention thus has an object to provide a platefin heat exchanger, capable of preventing the externalleak of fluids performing heat exchange while suppress-ing the deterioration of performance or the increase insize or weight.[0012] The present invention provides a plate fin heatexchanger configured to perform heat exchange be-tween plural fluids, comprising: a heat exchange partmain body including layers of flow passages for carryingeach of the plural fluids arranged with partition walls eachof which is arranged between each of two adjacent saidflow passages respectively; heat transfer members each

of which is disposed within each of said flow passagesof said heat exchange part main body respectively, eachof said heat transfer member connecting said partitionwalls opposed across each of said flow passages totransfer the heat of the fluid flowing in each of said flowpassages to said opposed partition walls; sensing partsconnected to both outer sides of said heat exchange partmain body in the arrangement direction of said flow pas-sages respectively, each of said sensing parts includinga plurality of sealed spaces arranged in the arrangementdirection of said flow passages, and a sensor wall dis-posed to separate an outermost sealed space of saidplural sealed spaces from a sealed space on the innerside of said outermost sealed space; and a detectionmeans for detecting damage of said sensor wall.[0013] According to this configuration, by placing thesensor wall which is free from external leak of fluid evenin the event of damage such as hole or crackling in aposition where the fatigue by the thermal stress basedon the heat of the fluid is accumulated more than in eachpartition wall of the heat exchange part, accumulation ofthe thermal stress-based fatigue in each partition wallcan be detected by causing the sensor wall to be dam-aged by the thermal stress prior to each partition wall anddetecting this, and repair or the like can be performedbefore each partition wall is actually damaged by the ac-cumulation of fatigue to cause the external leak of thefluid. Further, by providing the detection means for de-tecting damage of the sensor wall, the fatigue by the ther-mal stress based on the heat of the fluid, which is accu-mulated in each partition wall, can be detected withoutexternal leak of the fluid.[0014] Concretely, when a sudden change in temper-ature or flow rate of fluid occurs, the space between thepartition walls opposed across each flow passage is ex-panded by the thermal expansion of the heat transfermembers to deform each partition wall. The deformationamount from the initial position in the outer partition wallin the arrangement direction of the flow passages is largerthan that in the central partition wall. This is attributed tothat the deformation is repeated in such a manner that apartition wall closer to the center deforms, and a partitionwall on the outer side of this deformed partition wall fur-ther deforms by the thermal expansion of the heat trans-fer member disposed between the partition wall and thepartition wall closer to the center. Accordingly, the sens-ing part is provided on the further outer side of the out-ermost flow passage in the arrangement direction of theflow passages, a plurality of sealed spaces arranged inthe same direction as the flow passages is provided inthe sensing part, and the sensor wall is provided in aposition to separate the sealed spaces from each other,whereby the sensor wall is deformed most seriouslybased on the thermal stress. Therefore, the suddenchange in temperature or the like of the fluid or the start-stop of the heat exchanger is repeated, and the defor-mation and return to initial position based on the heat ofthe fluid are consequently repeated, and as a result, the

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accumulation of the thermal stress-based fatigue is larg-est in the sensor wall. Thus, by placing the sensor wallin the position with the largest accumulation of the ther-mal stress-based fatigue in a manner such that no exter-nal leak of fluid is generated even if the sensor wall isdamaged, and detecting damage such as hole generatedin’ this sensor wall, the accumulation of the thermalstress-based fatigue in each partition wall can be detect-ed before the partition wall is actually damaged.[0015] In the plate fin heat exchanger according to thepresent invention, the detection means preferably in-cludes a pressurizing means for pressurizing the insideof one of the two sealed spaces with the sensor walltherebetween, and a pressure measuring means formeasuring pressure in the other sealed space.[0016] According to this structure, it is possible to ac-curately detect the presence of even initial damage, orminute hole or cracking generated in the sensor wall bymaintaining the pressure in the one sealed space by thepressurizing means and measuring the pressure in theother sealed space by the pressure measuring meanswhile.[0017] Concretely, by maintaining the pressure in theone sealed space at constant level by the pressurizingmeans, in case of the generation of damage such as holein the sensor wall, the fluid (e.g., nitrogen gas, etc.) inone sealed space leaks from the one sealed space tothe other sealed space through the hole or the like, andthe pressure in the other sealed space rises. Therefore,this pressure is measured by the pressure measuringmeans, whereby the presence of damage of the sensorwall can be detected.[0018] Preferably, the heat exchange part main bodyincludes an outside partition wall which separates an out-ermost flow passage of the flow passages in the arrange-ment direction of the flow passages from the outside, andeach of the sensing parts is connected to the heat ex-change part main body so that an innermost sealed spaceof the sealed spaces in the arrangement direction of theflow passages is adjacent to the outermost flow passageof the heat exchange part main body with the outsidepartition wall therebetween, and has strength enough toendure a situation such that the pressure within each ofthe sealed spaces is equal to the pressure within eachof the flow passages with the fluid flowing therein of theheat exchange part main body.[0019] According to this structure, even if the outsidepartition wall between the heat exchange part main bodyand the sensing part is damaged during operation of theheat exchanger, and the fluid flows into the sealed spaceof the sensing part through the damaged part, breakageof the sensing part by the pressure of this fluid can beprevented. Further, since the fluid leaked into the sealedspace is confined within the sealed space, the fluid canbe prevented from further leaking to the outside.[0020] The heat exchanger preferably includes a fluiddetection means for detecting the presence of the fluidin the innermost sealed space of the sealed spaces in

the arrangement direction of the flow passages.[0021] According to this structure, even if the fluid flowsfrom the outermost flow passage in the arrangement di-rection of the flow passages of the heat exchange partinto the innermost sealed space of the sensing part duringthe operation of the heat exchanger, the fluid detectionmeans detects this outflow, whereby the outflow of thefluid from the flow passage can be easily and surely de-tected. Further, since the fluid leaked to the innermostsealed space is confined within the sealed space, thefluid can be prevented from further leaking to the outside.[0022] Each of the sensing parts preferably has two ofthe sealed spaces. By providing two sealed spaces ineach sensing part, the fatigue by the thermal stress basedon the heat of the fluid, which is accumulated in eachpartition wall, can be detected without external leak ofthe fluid while suppressing the increase in size and weightof the heat exchanger.[0023] According to the present invention, it is possibleto provide a plate fin heat exchanger capable of prevent-ing external leak of fluid performing the heat exchangewhile suppressing deterioration of performance or in-crease in size and weight.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]

Fig. 1 is a schematic structural view of a plate finheat exchanger according to one preferred embod-iment of the present invention;Fig. 2 is a partially enlarged perspective view withpartial cutaway of a heat exchange part in the platefin heat exchanger;Fig. 3 is a cross-sectional schematic view of the heatexchange part and sensing parts;Figs. 4 illustrate a heat exchange part in a conven-tional heat exchanger, wherein Fig. 4A is an explod-ed perspective view thereof and Fig. 4B is a frontview thereof; andFig. 5 is a typical view showing a thermally expandedstate of the conventional heat exchange part.

PREFERRED EMBODIMENTS OF THE PRESENT IN-VENTION

[0025] One preferred embodiment of the present in-vention will be described in reference to the accompany-ing drawings.[0026] A plate fin heat exchanger (hereinafter also sim-ply referred to as "heat exchanger") according to thepresent invention is adapted to perform heat exchangebetween a first fluid and a second fluid both flowing there-in. More specifically, as shown in Figs. 1 to 3, a heatexchanger 1 includes a vertical box-shaped causing 2;and a heat exchange part 3 provided within the center ofthe casing 2, in which a first flow passage 30a for carryinga first fluid F1 and a second flow passage 30b for carrying

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a second fluid F2 are alternately arranged.[0027] The casing 2 includes a bottom header 21 anda top header 22 for the first fluid provided at the bottomand at the top thereof respectively. The casing 2 furtherincludes an upside header 23 and a downside header 24for the second fluid provided at an upside and a downsideportions thereof respectively. A first fluid inlet pipe 21afor taking in the first fluid F1 into the heat exchanger 1 isconnected to the bottom header 21, and a first fluid outletpipe 22a for discharging the first fluid F1 out of the heatexchanger 1 is connected to the top header 22. A secondfluid inlet pipe 23a for taking in the second fluid F2 intothe heat exchanger 1 is connected to the upside header23, and a second fluid outlet pipe 24a for discharging thesecond fluid F2 out of the heat exchanger 1 is connectedto the downside header 24.[0028] A heat exchange part 3 is disposed at a verti-cally central portion within the casing 2, and an upperdistribution part 25 and a lower distribution part 26 aredisposed over and below the heat exchange part 3 re-spectively. The upper distribution part 25 is an area forguiding the second fluid F2 taken into the upside header23 from the second fluid inlet pipe 23a to each secondflow passage 30b of the heat exchange part 3 and alsoguiding the first fluid F1 passed through each first flowpassage 30a of the heat exchange part 3 to the top head-er 22. On the other hand, the lower distribution part 26is an area for guiding the first fluid F1 taken into the bottomheader 21 from the first fluid inlet pipe 21a to each firstflow passage 30a of the heat exchange part 3 and alsoguiding the second fluid F2 passed through each secondflow passage 30b of the heat exchange part 3 to thedownside header 24.[0029] According to such a structure, the first fluid F1supplied to the heat exchanger 1 is taken from the firstfluid inlet pipe 21a into each first flow passage 30a of theheat exchange part 3 successively through the bottomheader 21 and the lower distribution part 26, passedthrough each first flow passage 30a, and then dischargedfrom the first fluid outlet pipe 22a successively throughthe upper distribution part 25 and the top header 22. Onthe other hand, the second fluid F2 supplied to the heatexchanger 1 is taken from the second fluid inlet pipe 23ainto each second flow passage 30b of the heat exchangepart 3 successively through the upside header 23 andthe upper distribution part 25, passed through each sec-ond flow passage 30b, and then discharged from the sec-ond fluid outlet pipe 24a successively through the lowerdistribution part 26 and the downside header 24.[0030] The heat exchange part 3 includes a heat ex-change part main body 31 in which a number of flowpassages 30 (the first flow passages 30a and the secondflow passages 30b) are arranged in layers by alternatelyplacing the first flow passages 30a and the second flowpassages 30b; and a fin plate (heat transfer member) 32arranged within each of the flow passages 30. The heatexchange part main body 31 includes a plurality of par-tition plates (partition walls) 33, and a side bar 34 con-

necting the partition plates 33 to each other. The partitionplate 33 is a plate-like member capable of transferringheat between one surface and the other surface thereof,and in this embodiment, a rectangular plate-like memberformed of aluminum alloy such as A3003 is adopted. Theplurality of partition plates 33 are disposed at intervalsand parallel to each other. As materials of the partitionplate 33, an aluminum alloy such as A3003 is used inthis embodiment as an example, and titanium, copper,stainless steel or the like may be used.[0031] The side bar 34 is a member which connectsopposed partition plates 33 of the plurality of partitionplates 33 disposed at intervals, and forms the flow pas-sage 30 between the opposed partition plates 33 by seal-ing the space between the partition plates 33. The sidebars 34 are disposed along both sides of the space be-tween each two of the partition plates 33, and extendvertically along the sides of the partition plates 33 whilesealing the space between each of the adjacent two ofthe partition plates 33. As materials of the side bar 34,an aluminum alloy such as A3003 is used in this embod-iment as an example, and titanium, copper, stainlesssteel or the like may be used.[0032] By disposing the partition plates 33 and the sidebars 34 in this manner, the flow passage 30 enclosed bya pair of partition plates 33 and a pair of side bars 34disposed between these partition plates 33 is formed be-tween each two of the partition plates 33. Accordingly, inthe heat exchange part 3, a number of flow passages 30are arranged in layers (refer to Fig. 3). The passages 30include the first flow passages 30a for carrying the firstfluid F1 and the second flow passages 30b for carryingthe second fluid F2. The first flow passage 30a and thesecond flow passage 30b have the same structure. Inthis embodiment, since each of the first fluid F1 and thesecond fluid F2 are alternately flowed through each ofthe number of flow passages 30 arranged in layers, thefirst flow passages 30a and second flow passages 30bare alternately arranged in the heat exchange part 3.[0033] The fin plate 32 is a member disposed withineach flow passage 30 to connect the partition plates 33opposed across the flow passage 30 and to transfer theheat of the fluid F1 or F2 flowing in the flow passage 30to the opposed partition plates 33. Namely the fin plate32 is a member for improving the heat exchange efficien-cy of the heat exchange part 3 by ensuring, within eachflow passage 30, the contact area with the fluid flowingin the flow passage 30. Concretely, the fin plate 32 is asheet member repetitively protruded and recessed in thewidth direction of the flow passage 30 (the direction ofarrow α in Fig. 2) so as to alternately contact with thepartition plates 33 opposed across the fin plate 32, inother words, a corrugated plate-like member. The thus-constituted fin plate 32 is larger in thermal expansioncoefficient than the side bar 34. This difference in thermalexpansion coefficient is resulted from the difference inheat capacity or rigidity of each member based on shape,size or the like. As materials of the fin plate 32, an alu-

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minum alloy such as A3003 is used in this embodimentas an example, and titanium, copper, stainless steel orthe like may be used.[0034] Sensing parts 35 are connected respectively toboth outer sides in the arrangement direction of the flowpassages 30 (in the vertical direction in Fig. 3) of the thus-constituted heat exchange part 3. In other words, thesensing parts 35 are connected to the heat exchangepart 3 so as to sandwich the heat exchange part 3 fromboth the outer sides in the arrangement direction of theflow passages 30. Each of the sensing parts 35 includesa sensor plate (sensor wall) 36 which is more easily dam-aged by the thermal stress based on the heat of the fluidflowing in the flow passage 30 than each partition plate33 of the heat exchange part 3. Concretely, each sensingpart 35 internally has a plurality of (two in this embodi-ment) sealed spaces 30c arranged in the arrangementdirection of the flow passages 30, and the sensor plate36 is disposed so as to separate the outermost sealedspace 30c in the arrangement direction of the plurality ofsealed spaces 30c from the sealed space 30c on theinner side thereof.[0035] In this embodiment, the sensing part 35 isformed integrally with the heat exchange part 3. Con-cretely, the sensing part 35 is formed by placing a pluralityof (two in this embodiment) partition plates 33 along eachboth of the outer sides of the heat exchange part 3 in thearrangement direction of the flow passages 30 in paralleland at intervals, and sealing the entire circumference ofthe space between each two of the partition plates 33including the same fin plate 32a as in the heat exchangepart 3 therein with side bars 34a. In the sensing part 35,the sealed space 30c is formed between a pair of partitionplates 33 by sealing the entire circumference of the pairof partition plates 33 with the side bars 34a. The secondoutermost partition plate 33 in the arrangement directionof the flow passages 30 constitutes the sensor plate 36.Namely, since the degree of accumulation of the fatigueby the thermal stress based on the heat of the fluid F1or F2 is differed among the plurality of partition plates 33arranged in parallel depending on the arrangement po-sition thereof, and the accumulation of the fatigue is larg-est in the second outermost partition plate 33 in this em-bodiment, the partition plate 33 of this position is takenas the sensor plate 36. This is attributed to that the de-formation amount from the initial position of the partitionplate 33 based on the difference in thermal expansioncoefficient between the fin plate 32 and the side bar 34is increased toward the outer side in the arrangementdirection of the flow passages 30.[0036] In this embodiment, the same plate is used forthe partition plate 33 of the sensing part 35 and the par-tition plate 33 of the heat exchange part 3, and the sameplate is used for the fin plate 32a of the sensing part 35and the fin plate 32 of the heat exchange part 3. The sidebar 34a of the sensing part 35 and the side bar 34 of theheat exchange part 3 are formed of the same material.Therefore, the sensing part 35 has strength enough to

endure a situation such that the pressure in the sealedspace 30c is equal to the pressure in the flow passage30 with the high pressure fluid F1 or F2 in the heat ex-change part 3 flowing therein.[0037] An outside sheet 37 for protecting the heat ex-change part 3 and the sensing part 35 is provided on theoutside of the sensing part 35.[0038] A detection means 50 for detecting damage ofthe sensor plate 36 is provided for each sensing part 35constituted as above. The detection means 50 includesa pressure measuring means 51, a pressurizing means52, and a gas leak check means (fluid detection means)53. As the pressure measuring means 51 for measuringpressure within each sealed space 30c, a pressuregauge is used in this embodiment. The pressurizingmeans 52 for pressurizing the inside of each sealedspace 30c is configured to pressurize the inside of thesealed space 30c by feeding nitrogen gas into the sealedspace 30c in this embodiment. The gas leak check means53 checks the presence of the fluid F1 or F2 in eachsealed space 30c.[0039] Concretely, pipes 55 connecting with the re-spective sealed spaces 30c are connected to each sens-ing part 35, and each of the pipes 55 is branched to threebranch pipes (a first branch pipe 55a, a second branchpipe 55b, and a third branch pipe 55c). The branch pipes55a to 55c are provided with valves 56a to 56c respec-tively, the pressure measuring means 51 is connectedto the first branch pipe 55a, the gas leak check means53 is connected to the second branch pipe 55b, and thepressurizing means 52 is connected to the third branchpipe 55c. The pipe 55 communicating with the outersealed space 30c in the arrangement duration of the flowpassages 30 is communicated with the pipe 55 commu-nicating with the sealed space 80c on the inner side there-of through a connecting pipe 57, and the connecting pipe57 is provided with a valve 58.[0040] In the heat exchanger 1 constituted as above,heat exchange is performed between the first fluid F1(natural gas based on methane of 40°C in this embodi-ment) and the second fluid F2 (natural gas based onmethane of -40°C in this embodiment) by starting theheat exchanger 1, taking the first fluid F1 from the firstfluid inlet pipe 21a into the heat exchanger 1, and alsotaking the second fluid F2 from the second fluid inlet pipe23a into the heat exchanger 1. Specific fluids and tem-perature used in the heat exchange through the heat ex-changer 1 are never limited to the above-mentioned gas-es or temperatures.[0041] Concretely, upon start-up of the heat exchanger1, the first fluid F1 guided from the first fluid inlet pipe 21ainto the heat exchange part 3 through the bottom header21 and the lower distribution part 26, and the second fluidF2 guided from the second fluid inlet pipe 23a into theheat exchange part 3 through the upside header 23 andthe upper distribution part 25 flow in mutually opposeddirections through each partition plate 33 (upwardly forthe first fluid F1 and downwardly for the second fluid F2

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in Fig. 1) in the heat exchange part 3. The first fluid F1and the second fluid F2 flow in the respective flow pas-sages 30 of the heat exchange part 3 in this way, wherebythe first fluid F1 and the second fluid F2 perform heatexchange through the partition plate 33 and the fin plate32 disposed within each flow passage 30 and in contactwith the partition plate 33.[0042] After operation of the heat exchanger 1 for apredetermined time, the supply of the first fluid F1 andsecond fluid F2 is stopped, and the heat exchanger 1 isalso stopped. The heat exchanger 1 repeats start andstop in this way.[0043] A sudden change in temperature or flow rateoften occurs in the first fluid F1 or the second fluid F2flowing in each flow passage 30 of the heat exchangepart 3 during operation of the heat exchanger 1. Thissudden change in temperature or flow rate can occur attimes other than the start or stop of the heat exchanger1. In such a case, the partition plate 33, the fin plate 32and the side bar 34 which are in contact with the first fluidF1 or second fluid F2 suddenly changed in temperatureor flow rate are thermally expanded. The deformationamount based on the thermal expansion is differedamong the partition plate 33, the fin plate 32 and the sidebar 34 since each member has a different coefficient ofthermal expansion. Concretely, since the fin plate 32 islarger in the coefficient of thermal expansion than theside bar 34 as described above, the partition plates 33with each flow passage 30 therebetween are deformedby the fin plate 32 arranged therebetween. In more detail,the side bar 34 does not expand so much by the heat ofthe fluid F1 or F2, while the fin plate 32 is apt to expandmore than the side bar 34 by the heat of the fluid F1 orF2. Therefore, the space between a pair of partition plates33 with each flow passage 30 therebetween is not somuch changed by the thermal expansion of the fin plate32 at the sides of the partition plate 33 where the sidebars 34 are disposed, but the space is broadened at anarea distant from the side bars 34, or at the center in thewidth direction of the flow passages 30. Upon such de-formation of the partition plate 33, a stress (thermalstress) resulting from the deformation is caused at a spe-cific site (concretely, in the vicinity of the side bars 34) ofthe partition plate 33.[0044] Since a number of (e.g., several hundreds) flowpassages 30 are arranged in layers in the heat exchangepart 3 in this embodiment, the deformation amount fromthe initial position of the partition plate 33 separating theflow passages 30 from each other increases from thecenter part toward the outer side (the upper side or lowerside in Fig. 3) (e.g., refer to Fig. 5). This is attributed tothat the deformation amount in each flow passage 30 isadded from the center part toward the outer side. Namely,the deformation is repeated in such a manner that a par-tition plate 33 on the center side is deformed, and a par-tition plate 33 on the outer side of this deformed partitionplate 33 is further deformed by the thermal expansion ofthe fin plate 32 disposed between the partition plate 33

and the partition plate 33 on the center side. Accordingly,the outer partition plate 33 in the arrangement directionof the flow passages 30 has the larger deformationamount.[0045] The partition plate 33 returns from the deformedstate to a flat state (initial position) when the distributionof the fluids F1 and F2 within the flow passages 30 isstopped, for example, by stop of the heat exchanger 1,since the thermally-expanded fin plate 32 contracts to itsoriginal state.[0046] In this way, the above-mentioned expansionand contraction are repeated at such sudden changes intemperature or flow rate of the fluid F1 or F2 distributedwithin the heat change part 3 as the repeated start andstop during the entire period of use of the heat exchanger1. And as a result, at the outer partition plate 33 with thelargest deformation amount, more fatigue based on thethermal stress is accumulated in the above specific site,whereby the probability of damage such as hole or crack-ing in the partition plate 33 becomes high.[0047] In the heat exchanger 1 of this embodiment,therefore, the sensing part 35 provided with the sensorplate 36 is provided on each outer side of the heat ex-change part 3, and the detection means 50 for detectingdamage of the sensor plate 36 is provided to detect thedamage, whereby the fatigue by the thermal stress basedon the heat of the fluid, which is accumulated in eachpartition plate 33, can be detected without external leakof the fluid F1 or F2.[0048] Namely, the sensor plate 36 which is free fromexternal leak of the fluid F1 or F2 even at the occurrenceof hole or cracking etc. is disposed in a position wherethe fatigue by the thermal stress based on the heat ofthe first fluid F1 is accumulated more than in each parti-tion plate 33 of the heat exchange part 3 (or an outsideposition in the arrangement direction), whereby the ac-cumulation of the fatigue based on thermal stress in eachpartition plate 33 can be detected by causing the sensorplate 36 to be damaged by the thermal stress prior toeach partition plate 33, and detecting this, and repair orthe like can be performed before each partition plate 33is actually damaged by the accumulation of the fatigueto cause the external leak of the fluid F1 or F2.[0049] The damage detection of the sensor plate 36 isperformed as described below.[0050] The valve 56a of the first branch pipe 55a of thepipe 55 communicating with the sealed space 30c on theouter side in the arrangement direction of the flow pas-sages 30 is opened, and the valve 56c of the third branchpipe 55c of the pipe 55 communicating with the closedspace 30c on the inner side of the sealed space 30c isopened. In this state, the pressure in the outer sealedspace 30c is measured by the pressure measuringmeans 51 connected to this outer sealed space 30c whilepressurizing the inner sealed space 30c by injecting ni-trogen gas thereto by the pressurizing means 52 con-nected to this inner sealed space 30c. Since the pressurein the outer sealed space 30c rises if damage such as

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hole or cracking occurs in the sensor plate 36 separatingthe outer sealed space 30c from the inner sealed space30c, the damage can be detected. Namely, if the damagesuch as hole occurs in the sensor plate 36, the pressurewithin the outer sealed space 30c rises since the nitrogengas filled in the inner closed space 30c leaks from theinner sealed space 30c to the outer sealed space 30cthrough the hole or the like. Therefore, this change inpressure is detected by the pressure measuring means51 connected to the outer sealed spaced 30c, wherebythe presence of the damage of the sensor plate 36 canbe detected.[0051] Such damage detection of the sensor plate 36may be regularly or periodically performed. The damagedetection of the sensor plate 36 can be performed oth-erwise by measuring the pressure in the inner sealedspace while maintaining the pressure in the outer sealedspace 30c by pressurization.[0052] The valve 56b of the second branch pipe 55bcommunicating with the inner sealed space 30c in thearrangement direction of the flow passages 30 is openedduring operation of the heat exchanger 1, whereby dam-age of the partition plate 33 separating the inner sealedspace 30c from the flow passage 30 of the heat exchangepart 3 can be detected. Concretely, if damage such ashole occurs in this partition plate 33, the fluid F1 or F2flows from the flow passage 30 into the inner sealedspace 30c through the hole or the like. Therefore, thedamage of the partition plate 33 can be detected basedon leak of the fluid F1 or F2 by analyzing the componentof the gas in the inner sealed space 30c by the gas leakcheck means 53 connected to the inner sealed space30c.[0053] Further, the valve 56b of the second branchpipe 55b communicating with the outer sealed space 30cis opened, whereby damage of the partition plate 33 sep-arating the inner sealed space 30c from the outer sealedspace 30c (the sensor plate 36) can be also detected inaddition to damage of the partition plate 33 separatingthe flow passage 30 from the inner sealed space 30c.Namely, the fluid F1 or F2 reaches from the heat ex-change part 3 to the outer sealed space 30c only whenboth the partition plates 33 are damaged. Therefore, thedamage of both the partition plates 33 can be detectedby analyzing the gas in the outer sealed space 30c tocheck whether the component of the fluid F1 or F2 iscontained therein.[0054] Further, the valve 56a of the first branch pipe55a communicating with the inner sealed space 30c isopened during operation of the heat exchanger 1, where-by the presence of damage of the partition plate 33 sep-arating the flow passage 30 of the heat exchange part 3from the inner sealed space 30c of the sensing part 35can be detected. Concretely, if damage occurs in thispartition plate 33, the fluid F1 or F2 flows into the innersealed space 30c, and the pressure in the inner sealedspace 30c rises. Therefore, this pressure rise is detectedby the pressure measuring means 51 connected to the

inner sealed space 30c, whereby the occurrence of thedamage of the partition plate 33 can be detected.[0055] The plate fin heat exchanger 1 of the presentinvention is never limited to the above-mentioned em-bodiment, and various changes or modifications can beperformed without departing from the gist of the presentinvention.[0056] Although two sealed spaces 30c are providedwithin each sensing part 35 in the above-mentioned em-bodiment, three or more sealed spaces may be providedwithout limitation. However, by providing two sealedspaces 30c in each sensing part 35, the fatigue by thethermal stress based on the heat of the fluid F1, whichis accumulated in each partition plate 33, can be detectedwithout external leak of the fluid F1 or F2 while suppress-ing the increase in size and weight of the heat exchanger1.[0057] In the detection means 50 in this embodiment,the pressure measuring means 51, the pressurizingmeans 52 and the gas leak check means 53 are con-nected to each sealed space 30c of the sensing part 35through the pipe 55. However, the connection is not lim-ited to this embodiment. In the detection means 50, atleast the pressurizing means 52 is connected to one ofthe two sealed spaces 30c with the sensor plate 36 ther-ebetween to pressurize the inside of the one sealedspace 30c, and at least the pressure measuring means51 is connected to the other sealed space 30c to measurethe pressure in the other sealed space 30c.[0058] The detection means 50 may not include thegas leak check means 53. Namely, the gas leak checkmeans 53 may be provided independently from the de-tection means 50. In this case, the gas leak detectionmeans 53 may be connected to the innermost sealedspace 30c in the arrangement direction of the flow pas-sages 30. By connecting the gas leak check means 53in this way, even if damage such as hole occurs in thepartition plate 33 between the heat exchange part 3 andthe detection part 35 at the start (during operation) of theheat exchanger 1 to cause outflow of the fluid F1 or F2into the sealed space 30c of the sensing part 35 throughthe damaged portion, the gas leak check means 53 candetect this. Therefore, the outflow of the fluid F1 or F2from the flow passage 30 can be easily and surely de-tected. Further, since the fluid leaked into the sealedspace 30c is confined within the sealed space 30c, thefluid can be prevented from leaking to the outside. Fur-ther, since the sensing part 35 has the strength equal tothat of the heat exchange part 3, it is possible to preventthe damage or the like of the sensing part 35 by the pres-sure of the fluid F1 or F2 leaked from the flow passage30 of the heat exchange part 3 to the sealed space 30cof the sensing part 35.[0059] The heat exchange part 3 in this embodimentis configured so that two kinds of fluids F1 and F2 performheat exchange while flowing in opposite directions. Theheat exchange part 3 may be configured also so that thetwo kinds of fluids F1 and F2 flow in the same direction,

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or flow while crossing each other. In the heat exchangerpart 3, flow passages of F 1 and flow passages of F2may be arranged not alternatively. Namely, there are nolimitations in arrangement of the flow passages of thetwo kinds of fluid. Further, the heat exchange part 3 maybe configured also so that heat exchange is performedbetween three or more kinds of fluid. Also in this case,there are no limitations in arrangement of the flow pas-sages of the three or more kinds of fluid. In any of theheat exchange part 3 explained above, the fatigue basedon the thermal stress is likely to accumulate in the outerpartition plate 33 in the arrangement direction of the flowpassages 30 due to the thermal expansion, when anumber of flow passages 30 are arranged in layers, andthe fin plate 32 is disposed in each flow passage 30.Therefore, by providing the sensing part 35 and the de-tection means 50 therein, the same effect as in this em-bodiment can be attained, or the fatigue by the thermalstress based on the heat of the fluid, which is accumu-lated in each partition wall, can be detected without ex-ternal leak of the fluid.[0060] A plate fin heat exchanger of the present inven-tion includes a heat exchange part including a heat ex-change part main body including layers of plural flow pas-sages, and heat transfer members each of which is dis-posed within each flow passage of the heat exchangepart main body to transfer the heat of fluid flowing in eachof the flow passages to each partition walls opposedacross the flow passage; and sensing parts connectedto both the outsides of the heat exchange part respec-tively. Each of the sensing parts includes plural sealedspaces, and a sensor wall disposed to separate the out-ermost sealed space from the sealed space on the innerside thereof. The plate fin heat exchanger further in-cludes a detection means for detecting damage of thesensor wall of the sensing part. According to such a struc-ture, external leak of the fluid performing the heat ex-change can be prevented while suppressing deteriora-tion of performance or increase in size or weight.

Claims

1. A plate fin heat exchanger configured to perform heatexchange between plural fluids, comprising:

a heat exchange part main body including layersof flow passages for carrying each of the pluralfluids arranged with partition walls each of whichis arranged between each of two adjacent saidflow passages respectively;heat transfer members each of which is dis-posed within each of said flow passages of saidheat exchange part main body respectively,each of said heat transfer member connectingsaid partition walls opposed across each of saidflow passages to transfer the heat of the fluidflowing in each of said flow passages to said

opposed partition walls;sensing parts connected to both outer sides ofsaid heat exchange part main body in the ar-rangement direction of said flow passages re-spectively, each of said sensing parts includinga plurality of sealed spaces arranged in the ar-rangement direction of said flow passages, anda sensor wall disposed to separate an outermostsealed space of said plural sealed spaces froma sealed space on the inner side of said outer-most sealed space; anda detection means for detecting damage of saidsensor wall.

2. The plate fin heat exchanger according to claim 1,wherein said detection means includes a pressuriz-ing means for pressurizing the inside of one of saidtwo sealed spaces with said sensor wall therebe-tween, and a pressure measuring means for meas-uring pressure in the other sealed space.

3. The plate fin heat exchanger according to claim 1,wherein said heat exchange part main body includesan outside partition wall whichseparates an outermost flow passage of said flowpassages in the arrangement direction of said flowpassages from the outside, andeach of said sensing parts is connected to said heatexchange part main body so that an innermostsealed space of said sealed spaces in the arrange-ment direction of said flow passages is adjacent tosaid outermost flow passage of said heat exchangepart main body with said outside partition wall ther-ebetween, and has strength enough to endure a sit-uation such that the pressure within each of saidsealed spaces is equal to the pressure within eachof said flow passages with the fluid flowing thereinof said heat exchange part main body.

4. The plate fin heat exchanger according to claim 1,further comprises a fluid detection means for detect-ing the presence of the fluid in said innermost sealedspace of said sealed spaces in the arrangement di-rection of said flow passages.

5. The plate fin heat exchanger according to claim 1,wherein each of said sensing parts has two of saidsealed spaces.

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REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the Europeanpatent document. Even though great care has been taken in compiling the references, errors or omissions cannot beexcluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• JP 7167580 A [0002]