US3818984A - Heat exchanger - Google Patents

Abstract

A heat exchanger for heat exchange between low-temperature and high-pressure air and high-temperature and low-pressure gas comprising a housing, a plurality of partition members disposed substantially radially in the housing for defining therebetween alternate air and gas passages for passing the air and gas in directions opposite to each other, a first corrugated fin disposed in each air passage, and a second corrugated fin disposed in each gas passage. The first fins are suitably cut out at one end thereof to communicate with an air inlet of the heat exchanger, and the second fins are suitably cut out at the end remote from the cut-out end of the first fins to communicate with a gas inlet of the heat exchanger so as to attain satisfactory heat exchange between the two fluids.

Description

United States Patent [191 Nakamura et al.

[ HEAT EXCHANGER [75] Inventors: Kenya Nakamura, Okazaki; Makoto Kuroyanagi, Hekinan, both of Japan [73] Assignee: Nippondenso Co., Ltd., Kariya-shi,

Japan Filed: Jan. 17, 1973 App]. No.: 324,300

[30] Foreign Application Priority Data Jan. 31, 1972 Japan 47-12891 Apr. l8, 1972 Japan 47-46233 [52] US. Cl. 165/166, 165/157 7 [51] Int. Cl.F28b 3/08 [58] Field of Search 165/166, 167, 60, 39.51, l65/141,l55, 157,164,165

[56] References Cited UNITED STATES PATENTS 2,368,732 2/1945 Wallgren 165/167 2,792,200 5/1957 Huggins et al. 165/148X 3,198248 8/1965 Stack 165/166 June 25, 1974 3,228,464 l/1966 Stein et al 165/166 Primary Examiner-Charles J. Myhre Assistant ExaminerTheophil W. Streule, Jr.

Attorney, Agent, or Firm-Cushman, Darby & Cushman [57] ABSTRACT A heat exchanger for heat exchange between lowtemperature and high-pressure air and hightemperature and low-pressure gas comprising a housing, a plurality of partition members disposed substantially radially in the housing for defining therebetween alternate air and gas passages for passing the air and gas in directions opposite to each other, a first corrugated fin disposed in each air passage, and a second corrugated fin disposed in each gas passage. The first fins-are suitably cut out at one end thereof to communicate with an air inlet of the heat exchanger, and the second fins are suitably cut out at the end remote from the cut-out end of the first fins to communicate with a gas inlet of the heat exchanger so as to attain satisfactory heat exchangebetween the two fluids.

5 Claims, 9 Drawing Figures PATENTEUJUNZSIQH SHEU 1 (IF 8 PATENTEDJUNZSW v 3;a1a.9a4

' ISHEUEUFS I I FIG. 2

PATENTEDJUNZSIBH SHEET 6 [IF 8 FIG 4 FIG. 9

PATENTED JUNE 5 I974 SHEET 5BF 8 FIG. 5

PATENTED JUNZS I974SHEET 8 OF 8 PATENTEI] JUNZ 51974 shit? 7 [1F 8 FIG. 7

PATENTEDJUNZSISHSHEEI 8 OF 8 0 0 I o o 5 W O OIIIIIHIO 4 o o m o m IO 0 m 0O 0 mm o I H I. O o k 8m ,o m mw m 0mm mm I @m l I nom nwm I mm 1 HEAT EXCHANGER This invention relates to heat exchangers, and more particularly to a heat exchanger of the kind preferably used with an engine such as a gas turbine engine for vehicles.

It is generally most important for a heat exchanger to accommodate the largest possible heat transfer area within a limited space, since the largeness of this heat transfer area is one of the greatest factors governing the performance of the heat exchanger. Recuperative heat exchangers known in the art include tube bundle tubefin heat exchangers employing solely tubes arranged in parallel and tube-fine type heat exchangers comprising the combination of tubes and fins. Plate-fin type heat exchangers comprising the combination of fluid conduits and corrugated fins manufactured by forming flat plates in the shape are especially widely employed for the reasons that such a heat exchanger is quite small in size and has a large heat transfer area. Further, these heat exchangers are classified into the parallel flow type, cross flow type and counter flow type depending on the directions of fluids placed in heat exchange relation. However, the conventional heat exchangers of the tube bundle type and tube-fin type have been defective in that there is a great restriction in the inner and outer effective heat transfer areas and the selection of working fluids is also subject to a limitation. Further, these heat exchangers have been defective in that a high heat exchange efficiency cannot be expected due to the fact that the working fluids must be inevitably passed in parallel flow or cross flow relation. The counterflow type heat exchanger in which working fluids are passed through adjoining conduits in counterflow relation has also been defective in that a complex arrangement is required for separating the different fluids from each other so that the fluids flowing into and out of the'adjoining conduits may not be mixed with each other. This type of heat exchanger has further been defective in that it is quite bulky due to the inclusion of many unnecessary dead spaces in the heat transfer zones and a very complex process and a long period of time are required for the manufacture.

With a view to obviate such prior art defects, it is an object of the present invention to'provide a novel and improved heat exchanger which comprises a cylindrical housing, a plurality of core units disposed radially within said housing, each said core unit including a plurality of partition members arranged in parallel for defining therebetween alternate passages for passing a first fluid and a second fluid in directions opposite to each other, a first corrugated fin disposed in each of said first fluid passages, and a second corrugated fin disposed in each of said second fluid passages, and a plurality of first fluid admitting space portions defined between the inner wall of said housing and said core units for communication with said-first fluid passages in said core units. The heat exchanger having the features set forth in the above is quite small in size and the effective heat transfer area can be adjusted as desired by suitably selecting the number of the first and second fluid passages and the number of the core units.

Another object of the present invention is to provide a heat exchanger of the above character in which at least one of said first and second fins is provided with a cut-out at one or either end thereof so as to pass the first and second fluids in the directions opposite to each other.

A further object of the present invention is to provide a heat exchanger comprising a cylindrical housing,a heat exchange unit disposed within said housing, a plurality of partition members disposed radially in said heat exchange unit for defining alternate passages for a first fluid and a second fluid, a first corrugated fin disposed in each of said first fluid passages, and a second corrugated fin disposed in each of said second fluid passages, at least one of said first and second fins being provided with a cut-out at one or either end thereof so as to pass these two different fluids through said alternate passages in directions opposite to each other. The heat exchanger having the features set forth in the above possesses a large heat transfer area and is quite small in size due to the fact that unnecessary dead spaces are substantially eliminated.

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a partly sectional side elevation view showing the structure of an embodiment of the present invention;

FIG. 2 is a partly sectional front elevation of the heat exchanger shown in FIG. 1;

FIG. 3 is a partly cut-away, enlarged perspective view showing the structure of one of the core units in the heat exchanger shown in FIG. 1;

FIG. 4 is an enlarged section of parts'of the air and gas passages in the core unit shown in FIG. 3;

FIG. 5 is a partly cut-away perspective view showing a modification of the core unit shown in FIG. 3;

FIG. 6 is a longitudinal section showing the structure of another embodiment of the present invention;

FIG. 7 is a side elevation of the left-hand half of the heat exchanger shown in FIG. 6;

FIG. 8 is a partly sectional perspective view showing the structure of the heat change unit in the heat exchanger shown in FIG. 6; and

FIG. 9' is an enlarged sectional view of parts of the heat exchanger shown in FIG. 6.

An embodiment of the present invention will be described with reference to FIGS. I to 4.

Referring to FIGS. 1 and 2, a cylindrical housing 1 forms an outer shell of a heat exchanger. A plurality ofcore units 2 are disposed radially within the housing 1 for the heat exchange between air at a low temperature and high pressure and gas at a high temperature and low pressure. A plurality of radially spacedmembers 3 connect the radially arrangedcore units 2 with one another in such a manner that a space 4 is defined between anytwoadjacent core units 2. Anarcuate space portion 5 is defined between the inner wall of the housing I and each of the radially outer connectingmembers 3 for admitting low-temperature and high-pressure air into eachcore unit 2. Each of these spaces 4 is closed gas-tight by thecore units 2 disposed on opposite sides thereof and by the associated coreunit connecting members 3. The heat exchanger is provided with a plurality offlange portions 5a for mounting on an apparatus such as a gas turbine engine. The lowtemperature and high-pressure air is supplied from a compressor (not shown) to be fed through an air inlet 6 of the heat exchanger into each arcuate air admittingspace portion 5, thence intoair inlet portions 2a of eachcore unit 2. The low-temperature and highpressure air is turned into high-temperature and highpressure air through the heat exchange with the hightemperature and low-pressure gas while passing through each core unit .2 and such air is discharged throughair outlet portions 2b of eachcore unit 2, thence through an air outlet 7 of the heat exchanger to be supplied to a combustor (not shown). The hightemperature and low-pressure gas is supplied through agas inlet 8 of the heat exchanger intogas inlet portions 20 of eachcore unit 2 to be subjected to heat exchange with the low-temperature and high-pressure air while passing through thecore unit 2, and the lowtemperature and low-pressure gas produced by the heat exchange is discharged throughgas outlet portions 2d of eachcore unit 2, thence through agas outlet 9 of the heat exchanger to the exterior. The direction of flow of the air in eachcore unit 2 is opposite to the direction of flow of the gas. Freely expansible sealing means 10 and 11 are disposed between the radially outer connectingmember 3 and a passage forming member 12 and between anotherpassage forming member 13 and aseal supporting member 14 respectively for eachcore unit 2.

Referring to FIGS. 3 and 4 showing in detail the structure of eachcore unit 2, a plurality ofrectangular partition members 15 of, for example, stainless steel are arranged in parallel to define therebetween alter- 'nate air andgas passages 17 and 18. Afirst fin 16a in corrugated form consisting of a series of rectangular portions is disposed in eachair passage 17 and asecond fin 16b in corrugated form consisting of a series of rectangular portions is disposed in eachgas passage 18 as shown. The first fins 16a. disposed in theair passages 17 defined between the associatedpartition members 15 are cut out in the form of a triangle at one end thereof to provide theair inlet portions 2a and are not cut to remain in the original rectangular shape at the other end thereof to provide theair outlet portions 2b. Similarly, thesecond fins 16b disposed in thegas passages 18 defined between the associatedpartition members 15 are cut out in the form ofa triangle at the end remote from the cut-out end of thefirst fins 16a to provide the gas inlet portions and are not cut out to remain in the original rectangular shape at the other end thereof to provide thegas outlet portions 2d. An L-shaped gas sealing member 19 is interposed gas-tight at its upstanding and horizontal portions between the corresponding opposite surface portions of each pair of thepartition members 15 defining thegas passage 18 therebetween. Similarly, an L-shapedair sealing member 20 is interposed air-tight at its upstanding and horizontal portions between the corresponding opposite surface portions of each pair of thepartition members 15 defining theair passage 17 therebetween. These sealingmembers 19 and 20 are alternately disposed in a confronting relationship as shown. Theseal supporting member 14 of, for example, L-like cross section is fixed gas-tight at a position at which the horizontally extending portions of theair sealing members 20 inter-.

sect the upstanding portions of the gas sealing members 19. Another supporting member 14' is fixedly disposed gas-tight at a position at which the upstanding portions of the air sealing members'20 intersect the horizontally In operation, referring to FIG. 2, air at a low temperature and high pressure supplied from the compressor (not shown) passes through the air inlet 6 of the heat exchanger into eacharcuate space portion 5, and after changing the direction of flow by 180, the air flows into theair inlet portions 2a of eachcore unit 2 to pass through theair passages 17 in thecore unit 2. Thus, the air flows in a direction X X shown by the solid line. On the other hand, gas at high temperature and low pressure flows through thegas inlet 8 of the heat exchanger into thegas inlet portions 20 of eachcore unit 2 to passthrough thegas passages 18 in thecore unit 2 in a direction Y Y shown by the dotted line Thus, the low-temperature and high-pressure air 'passing through theair passages 17 having thefirst fins 16a therein is brought into a satisfactory heat exchange relation with the high-temperature and low-pressure gas 7 which passes through thegas passages 18 having the pressure gas turns into low-temperature and lowextending portions of the gas sealing members 19. The

15 insuch a manner asto provide theairand gas inlet 2 portions Zaand 2cof the core.unit 2. f

' changer is small in size, has a large effective heat transpressure gas. Then, the high-temperature and highpressure air passes through theair outlet portions 2b of eachcore unit 2 to be supplied to the combustor (not shown) from the air outlet 7 of theheat exchanger while the low-temperature and low-pressure gas passes through thegas outlet portions 2d of eachcore unit 2 to be discharged to the exterior from thegas outlet 9 of the heat exchanger.

In the embodiment above described, the first andsecond fins 16a and 16b in eachcore unit 2 are cut out in a triangular form at one end thereof to provide theair inlet portions 2a andgas inlet portions 2c respectively. Referring to FIG. 5 showing a modification of thecore unit 2 shown in FIG. 3, thefirst fins 16a disposed in theair passages 17 are cut out in a triangular form at opposite ends thereof as shown, while thesecond fins 16b disposed in thegas passages 18 are not cut out and have a rectangular shape. The first andsecond fins 16a and 16b are alternately fixed between the partition members l5 defining the air andgas passages 17 and 18 so that the cut-out ends of thefirst fins 16a provide the air inlet andoutlet portions 2a and 2b, while the rectangular ends of thesecond fins 16b provide the gas inlet andoutlet portions 2c and 2d in eachcore unit 2. Further, although the closed space portions 4 are provided between thecore units 2 in the embodiment above described, these space portions 4 may be eliminated andadditional core units 2 may be disposed in these spaces so as to increase the effective heat transfer area;

It will be understood from the above description that, in the first embodimentof the heat exchanger according to the present invention, a plurality of partition members are parallelly disposed to define therebetween a plurality of alternate air and gas passages for passing air and gasin directions opposite to each other and are combined with heat transfer fins to constitute a core unit, a plurality of such core units being disposed radially within a cylindrical housing, and the air passages in eachcore unit communicate with an air admitting space portion defined between the inner wall of the cylindrical housing. and the core .unit. The structure,

above described is advantageous in-that the heat exfer area and can be very simply manufactured due to the fact that the air admitting space portion can be formed by mere disposition of each core unit in the radial portion within the cylindrical housing, thereby eliminating the need for provision of any especial air supply conduit for supplying air into the air passages of the core unit. Further, by virtue of the fact that the core units disposed within the housing are independent of each other, leakage of air and gas can be easily detected and leaking parts can be repaired during the steps of manufacture and assembling. Thus, heat exchanger is from any air or gas leakage and the gas and air passages can be easily cleaned. The present invention is further advantageous in that the effective heat transfer area of the heat exchanger can be easily adjusted by suitably increasing or decreasing the number of the core units and also by increasing or decreasing the heat transfer area of the partition members and fins. Furthermore, by virtue of the fact that air and gas pass through the alternate air and gas passages in directions opposite to each other, satisfactory heat exchange between the air and the gas can be attained. Moreover, any especial means are not required for causing flow of the air and gas in the opposite directions and the heat exchanger has a simplified structure. Further, the heat exchanger has a satisfactory mechanical strength due to the fact that the core units are housed within the cylindrical housing.

Another embodiment of the present invention will be described with reference to FIGS. 6 to 9. Referring to FIG. 6, aheat exchange unit 22 is housed within a cylindrical housing 21. Theheat exchange unit 22 is provided with an annular portion orring 23 which is bolted to the cylindrical housing 21 for fixing theheat exchange unit 22 to the housing 21. Theheat exchange unit 22 is supported within the housing 21 by a plurality ofstays 24 welded to theheat exchange unit 22. Theheat exchange unit 22 and housing 21 are mounted to the body of an apparatus such as a gas turbine engine (not shown) by aflange portion 25 and aring 26. Theheat exchange unit 22 includes aninner casing 27 which is closed at one end thereof. A plurality offirst fins 280,second fins 28b andpartition members 29 are alternately radially disposed around theinner casing 27. The first andsecond fins 28a and 28b are corrugated and have a width which is gradually enlarged from the inner toward the outer end. The assembly consisting of thesefins 28a, 28b andpartition members 29 is in the form of a thick-walled cylinder. As seen in FIGS. 6 and 8, thefirst fins 28a are cut out at one or right-hand end thereof, while thesecond fins 28b are cut out at the left-hand end remote from the cut-out end of thefirst fins 28a, and these first andsecond fins 28a and 28b are alternately arranged with thepartition members 29 interposed therebetween. A first L-shapedsealing member 30a is in sealing engagement with the radially inner end edges and right-hand end edges of thepartition members 29 disposed on opposite sides of each of thefirst fins 280 as seen in FIGS. 6 to 8. Similarly, a second L-shapedsealing member 30b is in sealing engagement with the radially outer end edges and left-hand end edges of thepartition members 29 disposed on opposite sides of each of thesecond fins 28b. Further, these first andsecond sealing members 30a and 30b intersect at the opposite ends thereof and therings 23 and 26 are welded to these intersecting portions to serve as a sealing means for these intersecting portions. Anouter casing 31 is secured as by soldering to the second L-shapedsealing members 30b, and theflange portion 25 is formed at the left-hand end of theouter casing 31 as seen in FIGS. 6 to 8. The right-hand end of theouter casing 31 registers with the starting position of the cut-out at the right-hand end of thefirst fins 28a, and the left-hand end of theinner casing 27 registers with the starting portion of the cut-out at the left-hand end of thesecond fins 28b as best shown in FIG. 6.

In operation, air at a low temperature and high pressure is supplied from a compressor (not shown) to pass through the space between the housing 21 and theouter casing 31 in a direction as shown by the arrow A. On the other hand, combustion gas at a high temperature and low pressure is supplied through the opening of thering 26 in a direction as shown by the arrow B. The low-temperature and high-pressure air flows then in a direction as shown by the arrow C to enter the triangular spaces defined by the cut-out ends of thefirst fins 28a,partition members 29 and first L-shapedsealing members 30a, thence into the air passages defined between thepartition members 29 and containing thefirst fins 28a therein to be discharged through the space between thering 26 and theouter casing 31 in a direction as shown by the arrow D. On the other hand, the high-temperature and low-pressure combustion gas flows in a direction as shown by the arrow E to enter the triangular spaces defined by the cut-out ends of thesecond fins 28b,partition members 29 and second L- shapedsealing members 30b, thence into the gas passages defined between thepartition members 29 and containing thesecond fins 28b therein to be discharged through the space between thering 23 and theinner casing 27 in a direction as shown by the arrow F. In the heat exchanger, heat exchange between the lowtemperature and high-pressure air and the hightemperature and low-pressure combustion gas occurs through the medium of the first andsecond fins 28a, 28b andpartition members 29. As a result, the air supplied in the low-temperature and high-pressure state is turned into high-temperature and high-pressure air and such air is fed in the direction of the arrow D to be supplied into the combustor in the gas turbine engine (not shown) for combustion, while the combustion gas supplied in the high-temperature and low-pressure state is turned into low-temperature and low-pressure gas and such gas is discharged to the exterior in the direction of the arrow F.

' In the second embodiment of the present invention, thefirst fins 28a andsecond fins 28b are cut out at their right-hand and left-hand ends in the manner shown in FIG. 6 so as to provide the air and combustion gas inlet portions respectively. However, thefirst fins 28a may be cut out at the left-hand end thereof as shown by the two-dot chain line in FIG. 6 in addition to the cut-out at the right-hand end thereof, while thesecond fins 28b may not be cut out at either end thereof, and the shape of the first and second L-shapedsealing members 30a and 30b may be slightly modified. In such a modification, the air and combustion gas flow in respective directions as shown by the two-dot chain lines and satisfactory heat exchange between the air and the combustion gas can be similarly effectively attained.

What is claimed is:

l. A heat exchanger comprising a cylindrical housing, a plurality of partition members disposed within said housing for defining alternate passages for a first fluid and a second fluid, first corrugated fins are each disposed in each of said first fluid passages, second corrugated fins are each disposed in each of said second fluid passages, at least one of said first and second fins being formed with oblique cut out portions at at least one end thereof so as to provide inlet portions for introducing said two fluids into said alternate passages in directions opposite to each other.

2. A heat exchanger comprising a cylindrical housing, a plurality of core units disposed radially'within said housing, each of said core units having a square cross section and including a plurality of partition members arranged substantially parallel to one another for defining therebetween alternate passages for passing first and second fluids in opposite directions, first corrugated fins one each disposedin each of said first fluid passages, second corrugated fins one each disposed in each of said second fluid passages, one of said first and second corrugated fins being formed with oblique cut out portions at their radially outer ends so as to provide inlet portions to introduce said first or second fluid into said first or second fluid passages, a plurality of fluid admitting space portions defined between the inner wall of said housing and radially outer surfaces of said core units for communication with said first or second fluid passages in said core units through said cut out portions,and a cylindrical space defined by the radially inner surfaces of said core units at a center portion in said housing for communication with the other of said first and second fluid passages.

3. A heat exchanger as defined inclaim 2, wherein oblique cut out portions are formed also at the radially and second fluid passages being opened to said fluid admitting space portions, said cut out portions of the corrugated fins disposed in the other of said passages being opened to said cylindrical space.

4. A heat exchanger comprising a cylindrical housing, a heat exchanger unit disposed within said housing, said heat exchanger unit including a plurality of partition members disposed radially for defining alternate passages for a first fluid and a second fluid, first corru- V gated fins each having a wedge-shaped cross section and being disposed in each of said first fluid passages, second corrugated fins each having a wedge-shaped cross section and being disposed in each of said second inner endsof the corrugated fins disposed in the other i of said first and second fluid passages, said cut out portions of the corrugated fins disposed in one of said first inner periphery of said heat exchanger unit at a center portion in said housing for communication with the other of said first and second fluid passages.

5. A heat exchanger as defined in claim 4, wherein oblique cut out portions are formed also at the radially inner ends of the corrugated fins disposed in the other of said first and second fluidpassages, said cut out portions of the corrugated fins disposed in one of said first and second fluid passages being opened to said fluid admitting portion, saidcut out portionsof the corrugated fins disposed in the other of said passages being opened to said cylindrical space.

Claims (5)

1. A heat exchanger comprising a cylindrical housing, a plurality of partition members disposed within said housing for defining alternate passages for a first fluid and a second fluid, first corrugated fins are each disposed in each of said first fluid passages, second corrugated fins are each disposed in each of said second fluid passages, at least one of said first and second fins being formed with oblique cut out portions at at least one end thereof so as to provide inlet portions for introducing said two fluids into said alternate passages in directions opposite to each other.

2. A heat exchanger comprising a cylindrical housing, a plurality of core units disposed radially within said housing, each of said core units having a square cross section and including a plurality of partition members arranged substantially parallel to one another for defining therebetween alternate passages for passing first and second fluids in opposite directions, first corrugated fins one each disposed in each of said first fluid passages, second corrugated Fins one each disposed in each of said second fluid passages, one of said first and second corrugated fins being formed with oblique cut out portions at their radially outer ends so as to provide inlet portions to introduce said first or second fluid into said first or second fluid passages, a plurality of fluid admitting space portions defined between the inner wall of said housing and radially outer surfaces of said core units for communication with said first or second fluid passages in said core units through said cut out portions, and a cylindrical space defined by the radially inner surfaces of said core units at a center portion in said housing for communication with the other of said first and second fluid passages.

3. A heat exchanger as defined in claim 2, wherein oblique cut out portions are formed also at the radially inner ends of the corrugated fins disposed in the other of said first and second fluid passages, said cut out portions of the corrugated fins disposed in one of said first and second fluid passages being opened to said fluid admitting space portions, said cut out portions of the corrugated fins disposed in the other of said passages being opened to said cylindrical space.

4. A heat exchanger comprising a cylindrical housing, a heat exchanger unit disposed within said housing, said heat exchanger unit including a plurality of partition members disposed radially for defining alternate passages for a first fluid and a second fluid, first corrugated fins each having a wedge-shaped cross section and being disposed in each of said first fluid passages, second corrugated fins each having a wedge-shaped cross section and being disposed in each of said second fluid passage, one of said first and second fins being formed with oblique cut out portions at their radially outer ends so as to provide inlet portions to introduce said first or second fluid into said first or second fluid passages, respectively, a plurality of fluid admitting space portions defined between the inner wall of said housing and the outer periphery of said heat exchanger unit for communication with said first or second fluid passages in said heat exchanger unit through said cut out portions, and a cylindrical space defined by the inner periphery of said heat exchanger unit at a center portion in said housing for communication with the other of said first and second fluid passages.

5. A heat exchanger as defined in claim 4, wherein oblique cut out portions are formed also at the radially inner ends of the corrugated fins disposed in the other of said first and second fluid passages, said cut out portions of the corrugated fins disposed in one of said first and second fluid passages being opened to said fluid admitting portion, said cut out portions of the corrugated fins disposed in the other of said passages being opened to said cylindrical space.

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