DE2812056A1 - HEAT EXCHANGER - Google Patents

Description

March 20, 1978

COMMISSARIAT A L'ENERGIE ATOMIQUE 29, rue de la Federation, F-75015 Paris

Warmth from t au s before r

The invention relates to a circular heat exchanger which contains a tube bundle through which fluid flows, the tubes of which are arranged parallel to one another in the vertical direction. The tubes are immersed outside the heat exchanger into a primary fluid, and they are traversed in their interiors by a secondary fluid, the enables a mutual heat exchange. The tubes are in the interior of a cylindrical outer jacket in the circumferential direction arranged distributed, which spatially limits the heat exchanger.

The invention is particularly concerned with a heat exchanger, which serves as an intermediate heat exchanger in a nuclear reactor with fast neutrons. The primary fluid is

TELEPHONE (OBO) 33 3869 ■

TELEX OB-

TELECOPER

formed here by a liquid metal, generally sodium. After the heat absorption of the liquid metal as it passes through the reactor core, it enters the heat exchanger, then becomes as it flows through is cooled while touching the tubes arranged distributed in the outer jacket and is then cooled with the aid of Pumps fed back into the reactor core to turn through to go through this. In such a heat exchanger, the secondary fluid is mostly also a liquid one Metal is formed which usually has the same properties as the primary fluid that is in the interior of the tubes of the heat exchanger between an inlet header and an outlet header, which are each connected to the ends of the pipes. The primary fluid preferably flows and the secondary fluid countercurrently in the heat exchanger. Such a heat exchanger is for example described in DE patent application P 27 13 260.1.

In a heat exchanger designed in this way, the tubes through which a circulating flow flows are vertical arranged and connected at the end with plates, with so-called tube plates, some of the inlet and outlet limit the collector of the secondary fluid. The connection with the inlet collector is made via several lines, which according to the outer contour of the heat exchanger are arranged distributed. In other words, in such an embodiment, the sealing takes place aligned tubes of the tube bundle in place in the heat exchanger compared to the space required, which must be released in order to be able to introduce the closure or shut-off device. Furthermore it forms when one or more tubes of the tube bundle break, a mixture of radioactive primary fluid and non-radioactive fluid Secondary fluid, which has the consequence that you have to shut down the heat exchanger.

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The invention is concerned with a development circular trained heat exchanger of the type mentioned, in which the aforementioned disadvantages and difficulties can overcome, which occur in connection with defects in one or more tubes of the tube bundle.

According to the invention, a heat exchanger is characterized by this from that the tubes of the tube bundle are arranged divided into individual tube groups, each in the interior of a Individual jacket are arranged, the several adjacent modular in the outer jacket of the heat exchanger Forms units, and that each modular structural unit has separate inlet and outlet headers, which are each connected to an inlet and outlet duct for the secondary fluid.

The inlet and outlet lines for the secondary fluid are preferably the separate collectors of the modular ones Structural units themselves connected with two common collectors, which are intended as inlet and outlet collectors and which are arranged at a distance from the heat exchanger. In particular in one embodiment which the heat exchanger is arranged in an interior of the main container of a nuclear reactor with fast neutrons is, and in which the outer jacket is arranged hanging below a thick protective plate, which the main container closed at its upper part, the common inlet and outlet headers are outside the main container Provided above the protective plate, in turn of the inlet and outlet lines of the individual collector is traversed. The collectors can have any shape and are preferably circular or spherical .

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According to an advantageous development of the invention are. the inlet and outlet lines for the secondary fluid in the individual separate collectors coaxially and in one Axial plane of each modular unit arranged. According to Another modified embodiment is the inlet lines arranged distributed in the circumferential direction on one and the same circular plane as the modular structural units, and provide an interconnection between them and those coaxially in the modular assemblies arranged outlet pipes. According to a further embodiment of the invention, the inlet lines are arranged distributed on a circular plane, which lies within that formed by the modular structural units.

According to an essential feature of the invention, the heat exchanger has a main feed line for the primary fluid which is open at its upper end, so that the primary fluid flowing through the main line from bottom to top then flows from top to bottom into contact with the tubes forming a 'circulating flow, after it flows into each modular building unit entered through side windows is provided in the individual shells of each modular assembly. The primary fluid emerges from the Heat exchanger at the end lower than the jackets via further lateral windows. The main includes preferably two tubular elements which are inserted into one another, leaving a gap free, that between a space is limited, which is filled with a part of the standing primary fluid that of a neutral gas curtain is covered, which provides thermal and liquid insulation between the hot primary fluid on the inlet side of the heat exchanger and the cold primary fluid on the outlet side of the heat exchanger enables.

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According to a first advantageous embodiment of a Heat exchanger according to the invention is the main line at its upper open end in connection with a channel formed in a transverse plate fixed at its periphery to the inner surface of the outer shell of the heat exchanger is connected. This plate is made up of the individual coats of the modular Structural units traversed, which are arranged distributed around the main line within the space formed by the outer jacket are. The primary fluid rises up the main line and is through the transverse plate in the direction of the entry window of each module-shaped structural unit is directed, in which there is a circulating flow with contact the tubes forming the secondary fluid flows from top to bottom.

In the embodiment described immediately above, the main inlet line is preferably provided with a baffle plate connected which extends transversely above the open end of the conduit. The baffle forms a unit with the outer shell of the heat exchanger and serves as a deflector for the primary fluid by adding it directs the primary fluid towards the entry windows in the individual shells of the modular units.

According to the invention, the heat exchanger can also be shut down altogether in an emergency, and for this purpose there are Means provided that a pressurized, neutral gas in the main inlet line above the Initiate level of primary fluid to the flow of primary fluid stop in the various modular units by checking the level of the fluid in the line is lowered to a value below the entry window, which lead to the modular structural units.

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~ * ~ 2812058

According to a further embodiment of the invention, the heat exchanger is designed such that the individual Sheath of each modular structural unit is assigned to a line arrangement that connects to the side Manufactures entrance window of the modular structural unit. The line arrangement is usually so curved designed that it dips at its lower end into the main line open at its upper end to to enable a supply of primary fluid.

Each individual jacket is preferably modular Structural units in connection with a channel-shaped device, which is separately a pressurized introduces neutral gas and opens into the upper area of the jacket to the level of the primary fluid to lower a value below the assigned entry window and to increase the primary fluid flow in this module stop, thereby ensuring that each modular assembly is separately decoupled and taken out of service can be, while the other modular units can continue to work unchanged.

In particular, each has a modular structural unit assigned line arrangement a zone in the form of a section of a circle on, the boundary walls of the individual jacket of the modular structural unit to the main line run in such a way that the circle segment formed in this way includes the entirety of all modular structural units assigned line arrangements can accommodate, which are arranged distributed around this line. Preferably if the main line has a deflection device in the axial direction near the end of the line arrangements assigned to the modular structural units, which is a uniform Distribution of the primary fluid allowed on each of the line arrangements.

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Finally, according to an advantageous further development the invention also other devices can be provided that a feed of a neutral, under Allow pressurized gas into the space between the main line and the outer jacket at the end the individual jacket of the modular structural units forms around the jacket of the cold primary fluid outside to isolate the outer jacket.

Further details, features and advantages of an inventive circular heat exchanger emerge from the following description of preferred exemplary embodiments with reference to the accompanying drawing:

Figure 1 is a schematic cross-sectional view of a first embodiment of a heat exchanger,

Figure 2 is a sectional view along the line II-II in Figure Λ of a heat exchanger on an enlarged scale,

Figure 3 is a schematic view of another embodiment a heat exchanger,

Figure 4 is a partially cutaway view in partially section Representation along the line IV-IY in Figure 3>

Figure 5 is a sectional view of another embodiment of a heat exchanger,

Figures 6 and 7 are sectional views along the lines VI-VI and VII-VII in Figure 5,

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Figures 8 and 9 are sectional views along the lines VIII-VIII and IX-IX in Figure 9 and Figure 8 and show a further modified embodiment, and

Figures 10 and 11 are corresponding to Figures 8 and 9 Views along the section lines XI-XI and X-X of a further embodiment of a heat exchanger.

In Figure 1, 1 denotes the side wall of the main container of a nuclear reactor with fast neutrons. This container contains in particular a corresponding volume of a liquid metal, which is usually from Sodium is formed. This means forms the primary fluid. The container 1 is arranged hanging on its upper part J under a thick protective plate 4- extends horizontally above the level of the liquid metal 2 in the container and closes the container. In the interior of the main container 1, a second cylindrical container 5 is provided, which the reactor core or the Reactor core 6 surrounds and the hot, liquid that has accumulated in the container on the outlet side of the reactor core Metal separates from the cold liquid metal that is on the exit side of the heat exchanger in the area between containers 1 and 5 is replaced.

The embodiment of a heat exchanger denoted overall by 8 in FIG. 1 has a cylindrical outer jacket 9, the upper part of which runs through the plate 4- in such a way that that the heat exchanger is arranged hanging on this plate. The interior of this cylindrical outer jacket 9 is closed by a thick plug 10 which forms an extension of the plate.

809841/069

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According to the invention, the heat exchanger comprises several identical ones modular units which are adjacent to one another and in the interior of the jacket 9 in the circumferential direction are arranged distributed. Each modular unit has a cylindrical jacket 12 (Figure 2) on, in the interior of which a flow circuit forming tubes 13 arranged distributed in the form of separate Eohrbündeln that are vertical. In each modular structural unit, the tubes 13 are at their ends with two parallel Connected tube plates, which are designated accordingly with 14 and 15, which two housing parts 16 and 17 are assigned are, which in connection with the plates form collectors 18 and 19, which are for the entry and exit of a Secondary fluids are determined in or out of each modular structural unit, which along the inside of the tubes 13 flows. The primary fluid coming from the interior of the container 5 in the manner explained in more detail below enters the interior of each modular structural unit of the heat exchanger 8 via entry window 20, which in the cylinder jackets 12 of the various modular structural units 11 are provided. The primary fluid circulates in contact with the tubes 13 outside the same. Preferably, the supply of the primary fluid takes place in the case of the one shown Embodiment via a main line 21 which comprises two line sections. The first line section 22 extends over a pipe elbow 23 from the Heat exchanger to the outside, which is connected to a device 24, which is provided in the container 5 and contains the reactor core 6. The second line section of the line 21 is open at its upper end and carries a branch 26. The heat exchanger also has a transverse deflector plate 27 above the branch 26 of the axially extending feed line 21, which at its periphery on the outer jacket 9 of the heat exchanger is appropriate. The baffle 27 is even by the men

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means 12 of the modular structural units 11 traversed. Below the baffle 27 on the opposite side of the entrance windows 20 is a transverse, circular one Plate 28 arranged, which closes the space formed between the jacket 9 and the jackets 12 in order to avoid that the primary fluid does not flow to the outside of this jacket. The end of branch 26 is fixed at 29 connected to the circular plate 28 at the level of each entrance window 20.

In this embodiment described above, the hot primary fluid leaving the reactor core 6 collects in the interior of the container 3, is distributed in this interior and then exits in the direction of the double arrows 30 in the zone 31, and from there passes into the pipe bend 23 of the Main feed line 21. At the upper end of this main feed line 21, the primary fluid enters the module-shaped structural units 11 of the heat exchanger via the entry window 20 and flows into contact with the pipes from top to bottom, in order then to finally leave the jacket 12 via further windows 32, which are provided on the subsection thereof. Conversely, the secondary fluid flows in the interior of the tubes 13 in a countercurrent to the primary fluid, ie from bottom to top. The lower collectors 18 of each modular structural unit are supplied via a plurality of vertically extending lines 23 which are arranged in the interior of the jacket 9 distributed around the modular structural units. The secondary fluid then collects at the outlet of the tubes 13 in the collectors 19 and from there finally exits via the lines 34-. The respective inlet and outlet lines 33 and 3 ^ - each modular unit of the heat exchanger pull through the upper thick protective plate 4- in the area of the plug 10, which closes the space formed by the jacket 9, leaving passages 35 and 36 which are opposite to the

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Outside atmosphere are tightly sealed, which is ensured by FaI-tenbalge 37 or 38 or other equivalent means. The lines 33 and JA- are on the other hand in connection with two collectors, correspondingly designated 39 and 4-0, which are above the thick protective plate 4- outside the container 1. These collectors 39 and 4-0 form common components for the entirety of the modular structural units 11. The flow course of the secondary fluid is shown schematically in the drawing with arrows 4-1. In the space 4-2 between the two line sections 22 and 26 of the main feed line 21, a cushion made of an appropriately suitable neutral gas is preferably enclosed, which on the one hand isolates the hot primary fluid flowing in the line 21 and on the other hand isolates the modular units of the heat exchanger via the window 32 leaving cold primary fluid is insulated by keeping the level of the primary fluid constant in the space 9 outside the jackets 12 on the underside of the heat exchanger during operation. The neutral gas can also be pressurized in the interior of the line 21 at the same time in order to bring the level of the primary fluid below the inlet window 20 in order to stop the primary fluid flow in the heat exchanger in the entirety of the modular structural units in an emergency.

Figures 3 and 4- show a further modified embodiment of the heat exchanger, in which the same or similar components are provided with the same reference numerals are. In this embodiment, the main feed line 21 is also present, which is inside the outer jacket 9 is surrounded by modular heat exchange units, each with a special jacket 12 and have a tube bundle, the tubes of which are intended for the circulation of the secondary fluid. The tubes are modular in each one Component connected to individual collectors 18 and 19. These collectors are in turn via lines 33

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and 34- connected to two common collectors 39 and 4-0, which are above the protective plate 4-. These are at this embodiment is not circular as in the first embodiment, but spherical, however, one or the other embodiment can be used for such collectors.

In this modified embodiment in question, the entry windows 20 for the primary fluid, which are provided in each of the jacket 12, connected to conduit assemblies 50, each one curved Part 51 and include an open lower end 52 that connects to the upper open end 53 into the main line 21 below the level of the primary fluid in the space 4-2 is immersed. The primary fluid is displaced from the main line 21 and reaches each line arrangement each modular assembly according to the direction of the Supply arrows 30 separately. Preferably is a baffle 54- provided in the area of the axis of the line 21, in order to enable a homogeneous distribution of the quantity on each line arrangement 50.

In Figure 4- the cross-sectional profile is any of the foregoing Line arrangements shown. You have from the modular unit in the direction of the main line radially extending sides and because of their circular cross-sectional shape they are adjacent to one another arranged distributed in the line 21. Each modular unit works completely independently of the other. Thus, you can switch off each modular unit separately, without having to use the heat exchanger as a whole must shut down. For this purpose, each individual jacket is connected to a channel 55 through which the jacket enters pressurized gas can be introduced, which is suitable for the level of the primary fluid below the

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associated! window 20 to lower, so that one this modular Can take the unit out of operation. In addition, as in the first preferred embodiment, the between the jackets 12 and the jacket 9 area is also filled with a pressurized gas to isolate the heat exchanger from the cold, outside flowing primary fluid.

FIGS. 5, 6 and 7 deal with a further modified embodiment according to which the total space requirement for the heat exchanger can be further reduced, and in which the possibility is still retained of putting one modular unit out of operation while the others continue to work . In this embodiment, the supply lines 33 for the secondary fluid are arranged in each modular structural unit in the axial direction in the middle of the tubes 13 through which the fluid flows and they open at their lower part into collector 18, while the outlet lines 34- "are formed by circular lines which surround the lines 33 with a double wall 63 between them, which prevents excessive heat exchange. In this embodiment, a very compact structure of the heat exchanger is obtained. The secondary fluid coming from the axially extending line 33 in the direction of the arrows 64 rises in the interior of the tubes The heated secondary fluid is then discharged via the ring line 34-. The lines 33 ^{un <3} - 34 · are connected to collectors which are located outside the main container in a manner analogous to the previous embodiments and are arranged.

Figures 8 and 9 deal with another modified one Embodiment of the arrangement for the inlet pipes and the outlet of the secondary fluid. The heat exchanger includes a device that controls the primary fluid flow

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ORIGINAL INSPECTED

stops, and thus, as in the embodiments according to FIGS. 1 to 4, an overall or selective interruption the heat exchange between the primary fluid and the secondary fluid allowed. In this embodiment, the tubes 13 are divided into rectangular shapes Rooms 73 housed, each in a sector 71 » 72, which are separated from one another by radially extending partition walls 70. The inlet pipes for the secondary fluid alternate with the partition walls in one and the same circular plane. Each section 71 »72 ... is at theirs Upper part connected to an inlet line 66 for a neutral gas, in particular for argon. If you assume that certain pipes of a partitioned room in section 71 are defective, it is sufficient if only those of the section pressurizes associated line 65 with a gas, in order to lower the level of the primary fluid in the main line 26 to 67, i.e. below the circular plate, and to interrupt the heat exchange in the corresponding partitioned room. In the case of the illustrated eight separate rooms are planned. Thus, the heat exchanger designed in this way can with one on one Eighth of the reduced heat exchange area is still working. However, if you consider the total heat exchange between the If you want to stop the primary fluid and the secondary fluid, it is sufficient if you put the pressurized neutral gas in feeds all sectors in such a way that the level of the primary fluid formed by sodium falls, so that the sodium can no longer penetrate the partitioned off rooms.

In Figures 10 and 11 is a further embodiment of the arrangement of the inlet pipes and the outlet pipes for the secondary fluid shown. In this modified embodiment, the heat exchanger penetrates a projection on the inner container. The inlet pipes 33 are arranged in the central zone of the heat exchanger. The outlet pipes 34- are coaxial in the modular ones

809841/0694

Structural units 12 arranged. The tubes are through radial running partitions 81 divided. The primary fluid is supplied on the outer part of the heat exchanger via openings 62 which open into the chambers 83. The cooled primary fluid is drained off via openings 84 · placed at the bottom of the heat exchanger.

In a substantially similar manner to that described with reference to Figs Embodiment allow the lines, which are designated, for example, with 87, a feed of a pressurized neutral gas at the top of the chambers 83, so that the primary fluid up to the level 88 below the entry threshold around the pipes of a defective modular unit which has been put out of operation is displaced.

The heat exchanger is also used in this embodiment circular, contains the basic idea of a modular design and has a low overall required space, with the modular units in particular in a simple way .und Way in groups or separately from the primary fluid and the secondary fluid can be separated, for example at Repairing a defective pipe is necessary. This mode of operation is possible without having to use the heat exchanger must be shut down altogether and without intervening in the operation of the adjacent modular units got to.

809841 / 069A

Claims (16)

PATENT LAWYERS A. GRUNECKER OiPL-ING. H. KlNKELDEY Da-ΐΝα 2812058 W. STOCKMAlR - OR-INa-AeE (CALTECH) K. SCHUMANN _β DR RER NAT · DtPL-PHYS P. H. JAKOB G. BEZOLD DR RER NAT- CJPL-CHEM. 8 MUNICH MAXIMILIANSTRASSE A3 P 12 521 Claims Circular heat exchanger with a tube bundle, the tubes through which flow is parallel in the vertical direction lie, are immersed outside in a primary fluid and the interior of one for heat exchange Serving secondary fluid is flowed through, the tubes in the interior of a cylindrical outer jacket are arranged distributed in the circumferential direction, which limits the heat exchanger, characterized in that the tubes (15) of the bundle are arranged distributed in groups of individual tubes that each tube group is arranged in the interior of a separate jacket, which is in the outer jacket (9) of the heat exchanger (8) forms a plurality of adjacent 'lying modular structural units (11) that each modular unit (11) a separate inlet collector (18) and a separate outlet collector (19), each with a feed line (33) and a 80 9841/0694 TELEPHONE (OSO) 32 38 03 TELEX OS-SOSeO TELEGRAMS MONAPAT TELECOPER ORiGINAL INSPECTED! -2-2072H-SR Outlet line (34) connected for the secondary fluid are. 2. Heat exchanger according to claim 1, characterized in that the feed line and the outlet line (33, 34) for the secondary fluid at the individual collectors (18, 19) of the modular structural units (11) are in turn connected to two common collectors (39j 40), which are used as inlet and outlet collectors serve and are arranged at a distance from the heat exchanger. 3 · Heat exchanger according to claim 2, which is located in the interior of a main container of a nuclear reactor with fast neutrons is located and on its outer shell below a thick protective plate is arranged hanging, which closes the main container at its upper part, marked by the fact that the common inlet and outlet collectors (39> 40) are arranged outside the main container (1) above the protective plate (4), and that the protective plate (4) of the inlet and outlet lines (33 »34) of the individual collectors (18, 19) are traversed. 4. Heat exchanger according to claim 3, characterized in that the common collector (39 * 40) are circular or spherical for the secondary fluid. 5 · Heat exchanger according to one of claims 1 to 4, characterized characterized in that the inlet and outlet lines (33, 34) for the secondary fluid in the individual collectors (18, 19) are arranged coaxially and in the axial plane of each module (11). 809841/0694 6. Heat exchanger according to one of claims 1 to 5, characterized in that the inlet lines (33) for the secondary fluid of the individual modular Structural units in the circumferential direction on a common circular cross-sectional plane of the modular Units are arranged distributed, and between these and the coaxial outlet lines (3 * 0 in the modular Building units themselves lie. 7. Heat exchanger according to one of claims 1 to 6, thereby gekennz eichnet that the inlet lines for the secondary fluid on one of the modular structural units formed, inner circular plane are arranged distributed, and that the primary fluid enters each separate jacket (12) via a lateral opening (20) which is located on the outside of the Sheath (12) is provided. 8. Heat exchanger according to one of the preceding claims, characterized in that a main inlet line (21) for the primary fluid is provided, which is open at its upper end, so that the primary fluid flows through the axial line from bottom to top, then from top to bottom in Contact with the circulation pipes (13) flows after it through side windows (20) in each modular Unit (11) has occurred, which is in the. individual jackets (12) of each modular structural unit are provided, and that the primary fluid from the heat exchanger at the lower end of the jackets (12) via further side window (32) emerges. 9. Heat exchanger according to claim 8, characterized in that the main line (21) has two tubular Elements (22, 26) which are inserted into one another while maintaining a gap (4-2) in such a way that 809841/0694 that in between a space for a fluid film of the standing primary fluid is limited and remains free, which is covered with a gas curtain that is thermal and fluid Isolation of the hot primary fluid entering the heat exchanger and the one at the outlet end occurring cold primary fluids permitted. 10. Heat exchanger according to claim 8 or 9 »characterized in that the main line (21) to its open upper end is in communication with a channel in a transverse plate (28) is formed, which on its circumference firmly with the inner • surface of the outer jacket (9) of the heat exchanger connected is, and that the plate (28) is traversed by the individual jackets (12) of the modular structural units which are arranged distributed around the main line (21) in the space bounded by the jacket (9). 11. Heat exchanger according to one of claims 8 to 10, characterized in that the main line (21) is assigned a baffle plate (27) which runs transversely above the open end of the line, and that the baffle plate (27) firmly connected to the outer jacket (9) of the heat exchanger (8) is a deflection device forms for the primary fluid, and this in the direction of the entry window (20) in the separate Jackets (12) deflects the modular structural units. 12. Heat exchanger according to one of claims 8 to 11, characterized in that a device there is provided a pressurized gas in the main line (21) above the level of the primary fluid initiates the flow of the primary fluid in the various modular structural units (11, 12) stop by bringing the level of the fluid in the line to a level below the entry window (20) the modular construction units decreases. 809841/0694 13 · Heat exchanger according to one of claims 8 to 12, characterized gekennz eichnet that the individual jacket (12) of each modular unit with a Line arrangement (50) is in connection, which connects to a side entry window (20) of the module-shaped assembly produces, and that the line arrangement (50) is formed so suitably curved that it dips at its lower end into the main line, which is open at the upper end, in order to provide a primary fluid supply enable (Figures 3 and 4). 14. Heat exchanger according to claim 13, characterized in that each individual jacket (12) of the modular Structural units connected to a separate inlet channel for pressurized neutral gas is, which opens into the upper part of the jacket (12) to the level of the primary fluid to a value below the associated To lower the entrance window (20) and the flow of the primary fluid in this modular unit to stop. 15 · Heat exchanger according to claim 13 or 14, characterized in that each of a modular Line arrangement (50) assigned to the structural unit comprises a zone in the form of a segment of a circle (71 »72, ·. ·), its boundary walls radially from the individual jacket (12) of the modular structural unit to the main line (21) runs (Figures 8 and 9) 16. Heat exchanger according to one of claims 13 to 15 »thereby characterized in that the main duct (21) is near the end of the modular Line arrangements (50) associated with structural units have a deflection device (54) in the vicinity of their axis, an even distribution of the primary fluid 809841/0694 amount allowed on each line arrangement (50): ''. 17 · Heat exchanger according to one of claims 8 to 16, characterized in that a device is provided which a pressurized neutral gas in between the main line (21) and
the outer jacket (9) of the heat exchanger outside the individual jacket (12) of the modular structural units introduces space formed in order to isolate these jackets from the cold Erimärfluid outside the jacket (9). 809841/0694