DE1551021A1 - Forced circulation heat exchanger - Google Patents

Description

PIVES-EEIIHÖEI

Forced circulation heat exchanger

Priority: France, 8 November 1965

The invention relates to a heat exchanger with ornate circulation, which is preferably a steam generator forms and has bundles of straight vertically arranged Hohrelemente, in which a fluid to be evaporated flows, wherein the pipe elements are arranged in at least one jacket, in which the opposite direction to the to be evaporated Fluid a heat transfer medium flows.

Such an exchanger is intended in particular for use in a nuclear power plant in which the Exchanger is located in a chamber containing the reactor. In such a system, the heat transfer medium to be cooled is in the

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generally formed by carbonic anhydride, which forms the coolant of the reactor, while doü to. warming fluid is water.

As is known, the water flowing in the exchanger is located one after the other in the straight pipe elements in liquid state in a first section called "preheater", in the state of a mixture of water and water vapor in a second section called "evaporator" and closing in the steam state in a third section called "superheater".

The fact that these exchangers must be housed within the chamber containing the reactor, has considerable difficulties due to the limited amount of space available result, including the various pipelines for To accommodate water supply and steam discharge, which do not participate directly in the heat exchange, as one is possible large number of pipe elements for heat exchange, must accommodate in order to achieve the greatest possible efficiency · Similar difficulties arise in accommodating the ipag assembly.

As the exchanger is practically inaccessible are, as soon as the reactor is working, any repair during operation is excluded, so that it is essential to prevent asymmetries in the cooling of the heat exchanger from occurring if certain pipe elements are not connected to water fed v / earth.

The invention relates to a heat exchanger which can meet the various requirements of the equipment of nuclear power plants particularly well adapted and in particular

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which is notable for the fact that it is characterized by identical adjacent Uniform panels are formed, which have a certain Number of identical pipe elements included and separated identical units are combined, each of which forms an Eleraenta exchanger, these units so combined are that they are in one to the axes of the hearing elements. perpendicular plane has the shape of a polygonal. Wreath, so there is on the one hand between the outer outline of the wreath and the Y / and the Kanner in which the units are housed, and on the other hand in the central section of the rim

free spaces for accommodating the support assembly and AEEN passage of Wassersufuhrrohre and Dar.pfabfuhrrohre arise.

This arrangement enables ": in particular, a

completely homogeneous distribution of a very gros.-en number of exchange tube elements in the reactor containing Jen Kanner to erzieleni \ v ^r obei simultaneously su for access to the upper part of the exchanger spaces created required v / ground. Man. thus obtains a high filling coefficient, ie a high degree of efficiency of the exchanger and an expedient utilization ύ of the available plaice.

According to a further characteristic of the invention, the units are combined with one another in such a way that they form one hexagonal crana.

This hexagonal shape is particularly useful when the chamber has a circular outline.

According to a further characteristic of the invention, each sinality table is formed by a group of tubular elements, whose axes ran in the same plane and which ones to

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at each end connected to a single manifold, the axis of which is in the same plane as the axes of the pipe elements lies.

This distribution of the pipe elements on plane

Boards, which can thus easily be placed next to one another, simplify “the. Manufacture of the exchanger as well as its supply assembly considerable.

According to a further characteristic of the invention, the tubular elements of each panel are provided with at least one The collecting pipes are connected by flexible connections, the axes of which are in the same plane as the axes of the pipe elements lie, the division of the connections of these connecting pipes to the corresponding manifold smaller than the division the pipe elements is.

The presence of the flexible pipes makes it possible to compensate for the differential expansions which can occur between the various pipes of the same sheet, and since the flexible pipes which only take part in the heat exchange can be formed by simple pipes, the diameter of which is considerably smaller than that of the Pipe elements can be provided connection points that are closer together than would be possible with a direct connection of the pipe elements. You can therefore use manifolds whose length is less than that of the table, where-

Q is saved by space, which is useful for passage

oo the various supply and discharge lines are used oo

-" can.

^ _Λ>. According to another characteristic of the invention

The exchange units have an average of one

to the axes of the teaching elements perpendicular plane a polygonal shape.

j BAD ORIGINAL COPY

These units Fora a R _e chtecks, a square, einesiRhombus, a parallelogram, a hexagon or a regular or irregular polygon may have in cross-section, said form corresponding to the availability of the exchanger in the reactor chamber containing

a place-is-chosen.

According to one embodiment of the invention these units have a cross section in the form of a rhombus.

The rhombus-shaped cross-section allows for

the pipe network to obtain a division in the form of an equilateral triangle, which gives the best uniformity of distribution of the heat transfer gas guaranteed. Furthermore, if the chamber in which the exchanger is housed, it is circular is, the use of units in the shape of a rhombus is the best way of utilizing the available space.

Furthermore, according to the invention, several of each other independent flow circuits for the fluid to be heated provided, e.g. four flow circles, with animals

every fourth table of the same unit is connected.

You actually get four separate ones

Exchangers that are completely separate from each other but with each other are nested, what is permitted, in the event of failure of the supply of one or more of these exchangers, impermissible To avoid asymmetries in the cooling of the coolant of the reactor.

ο ■

The invention is hereinafter referred to

co on the. Drawing explained by way of example.

> Fig. 1 shows schematically a plan view of a

^ ₃ Auatauüchers according to the invention, which is partially cut according to four sectors A, B, C and D, so that the on

^. BAD OBIGiNAt GOPY

Different parts of the exchanger are located at different heights become visible.

Pig 2 shows in a side view breaking away of ropes a part of the exchanger formed by a unit table.

Pig. 3 is a section 1 "n ^ c of the line III-III of Pig.

Pig. 4 is a partial view seen from the side of the exchanger, v / which two through adjacent Unit tables shows units formed, of which one is shown in view and the other in Sc.mitt.

Pig. Fig. 5 is a fragmentary view of the upper portion of a in Pig. 4 unit shown in larger ci Ii ate st.

Pig. 6 is a side view of the superimposed Flocks of pipes for feeding the water collecting pipes a standard table.

Pig. 7 is a section along the line VII-VII the pig. 6th

Pig. S is a section along line VIII-VIII of Pig. 6th

Pig. Figure 9 is a schematic plan view of a unit comprising the vapor collection tube and those attached thereto Shows steam exhaust pipes.

Pig. 10 is a large-scale pictorial view showing the attachment of the steam headers shows on the splashing of the support assembly.

Pig 11 is a top plan view of the support assembly of the exchanger.

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Fi;:. 12 is a section along the line XII-XII of Fig. 11.

The illustrated embodiment of the invention is a '' Heat exchanger for steam generation with forced circulation, which housed in a chamber containing a nuclear reactor and is intended for cooling the gaseous coolant of the reactor, the circulation of the coolant in descending order Direction successful; t, during the circulation of the fluid to be heated, Water or water vapor, in an ascending direction going on. ^

This exchanger is scliemati. cn in ^ ¹ Ig. 1 shown in such a way that the training is visible in its various components.

For this purpose Fig.i is in four sectors A, 3, G and D. divided, which correspond to three sections in three different planes (A, B, O) and a plan view (D). Sector A corresponds to the lowest section of the aur exchanger. Sector B inclines the flocks of the esophagus;> the water sanine roll .-- The Sector C shows those in the lower part of the unit tables Yf ater plumbing pipes. Finally, sector D shows the steam ™ discharge pipes.

The exchanger is essentially flat Uniform tables 1 (Fi ^ .2) are formed, each of which has a certain Number of perpendicular straight pipe elements 2, which one layer von Rolireii pictures, whose axes lie in a 3-plane, and two

has headers, one of which, 3, on / in the lower part

of the table and is used to feed with liquid water, while the other, 4, is in the upper part of the table and serves for the evacuation of steam. The axes of these Saumelrohre lie in the same plane as the outer Rohreleniente. The panels ■ '-909881 / 0671 bad ORlSWL

are placed side by side in such a way that they separate rhombus-shaped form units designated as a whole with 5. Each a complete The unit forming the elementary exchanger is mixed with liquid water dtrch a bundle of curved lines marked 6, Pipes fed, which are arranged under the water collection tubes 3 is. Each unit is also located above the steam headers 4 whole with 7 designated bundle of steam discharge pipes.

I ¹ Ig. 1 shows the vessels 8 for water supply and steam discharge, which incidentally do not form part of the invention, as well as the water supply lines (connected to the bundles 6)

^ and the (connected to the pipes 7) leading the steam downwards lines 10.

The rhonbus-shaped units 5 are so with each other united that they form a hexagonal ring 11, which on the one hand a central space 12 and on the other hand between the Outer sides of the hexagonal ring 11 and the wall 13 of the circle fb "r; _igen Kar.uaer rooms 14 free. These rooms 12 and 14 allow Access to the upper part of the exchanger and be used for Down the associated with the steam discharge pipes 7, the Since:.: Vf down lines 10 as well as for various with

"It pipes connected to the reactor aur finding one Hull fracture, used to filter the GOg, etc. In these Murmurs are also the rush of the arrangement that supports the sinuses arranged, in particular the pillars supporting the upper beam 15, such as the pillar 15 arranged in the lute of the chamber.

The number of provided in each Binheitstafel Rolire 1 is relatively high and accordingly the division of the ITetses, velclie a Greiiz betting for the diameter of Samnelrohre determines the abglichen Lan ^ e of these collecting pipes, and

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the largest permissible dimensions for this table, determined, these dimensions being primarily different from that in the sur inclusion 'Space available for the exchanger in the specific chamber so / ie depend on the 'possibilities of handling and transport. In the illustrated case, the panel 1 has thirty-two tubular elements 2.

The connection of these drilling elements 2 to the water collecting pipe 3 is made by flexible connections 17 j which the Make it possible to compensate for the differential expansions that occur between the various tubular elements of one and the same panel can. These! Lines 17 are attached so that their axes are in the same plane as the axes of the pipe elements 2 and the Header pipes 3 and 4 are (see Fig. 3),

Each line 17 contains two consecutive opposing ICniee 18a, 18b, so that they are three approximately straight lines Sections 19a, 19] 2> 19c. The lines 17 are symmetrical with respect to ajtf one perpendicular to the lad el and through the Middle of the Sanmel pipes 3 and 4 level P arranged. In the left half of the table in Fig. 2 is the first section 19a of the line at the end inclined from right to left, their second section 19b, from left to right and finally its third section 19c, again from ashhts to litoks. the Sections 19a, 19]> »19 £ der at the end of the right half panel lying lines naturally have opposite inclinations.

The lines 17, in which the water in liquid State flows, require a smaller cross-section than the pipe elements 2. This small cross-section is used, around the division of the connections of the lines 17 aA the Wasseraammelleituag 3 to give a considerably smaller value than the division of the pipe elements themselves »This difference in division

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Y / is compensated by gradually increasing the inclination of the Section 1S '£ of the connecting lines 17 is changed. While • the opening angle between the first section 1 $ a and the second section 19b, for all lines 17 of both the left and the right half of the table remains the same, the angle between the section 19b and the section 19c from which from the plane of symmetry P the most distant line to the line closest to this plane of symmetry, where this third section in the two middle lines is practically in the "extension of the pipe elements on which they are connected.

This symmetrical arrangement of the lines 17 with respect to the plane P allows them to be accommodated in the space limited by the two ear elements at the ends of the panel.

The tubular elements 2 can be provided with ribs Elements or are formed by smooth tubes and be provided inside with devices, which the heat exchange coefficient raise. These tube elements are tapered at their ends 20 (see Pig. 3 to 5), thereby avoiding welds can be. The tapers 20 are made as long as possible, so that, if necessary, each pipe element directly can be connected to the corresponding manifold. These tapers are obtained by the fact that if necessary .. the outer

Ribs of the tubular element at the ends of the same abco accordingly

° be cut.
co

J £. The unified tables formed in this way are all

• ^ identical to each other, ie they are replaced by the same Zal

er) formed by tubular elements of the same length * where n'ar - * "the constrictions of the upper section of this RafcreHenieate '·

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in two adjacent panels, of different lengths, which allows the Danpfeanuaelrohre 4 of the opposite offsetting the others in height and making best use of the space available in the upper section of each unit.

gene

use, e.g. the one between the two / of two odd numbers Rohrelenenten vacated space to accommodate the SaBmebohre the even-numbered tables is exploited. From this it follows that the steam collection tube 4 in two on two different High lying rows are arranged, with the Sanmelrohre a row the spaces between the header pipes correspond to the other row (see Pig. 3 to 5).

The above standard tables are placed next to each other in such a way that that in the case shown they have a rhombus-shaped cross-section, which in the case of a circular chamber the best possible filling and by enabling a distribution of the pipe elements according to a division in the form of a equilateral triangles a most favorable distribution of the heat transfer gases enables.

It should be noted that in order to avoid the

Transport of units with excessive weights and dimensions these rhombuses in turn in several each, a subunit corresponding parallelograms can be decomposed.

Each unit 5 forms an elementary part exchanger, which its water supply and steam discharge pipes to and its dumbbell 22, which has a passage for forms the downward flowing heat carrier gases.

The lower manifolds 3 of each

ο Unit with VAbBert feeding pipes are on their own

^ bent like a needle (Pig. 6 and 7), so that flat arrays 6a, 6b_, 6c_, 6d. arise, which are given an outer outline,

which corresponds to that of the unit which these feed pipes are assigned, i.e. a rhombus shape in the embodiment shown.

These sets of feed tubes are vertical to the flow of the heat transfer gases and arranged one above the other. This creates a tube bundle 6 which is active participates in the heat exchange, and its position at the end of the path of the gases, i.e. at the point where the temperature differences are at their highest, allows them to homogenize these temperatures.

These superimposed groups 6a, 6Jb, 6 £, 6i are expediently given a position such that the straight pipe sections are parallel to the different sides of the quadrangle delimiting the exchanger unit, so that in the one shown - all the different groups alternate to the sides of the rhombus are parallel. This gives a bundle divided into squares, which is particularly effective for mixing the gases.

Furthermore, the bend in these feed pipes gives them sufficient flexibility to allow them to expand and can accommodate displacements.

As is well known, it is generally advisable not to use a single Vaesian circuit in an exchanger, but rather to provide several independent water circuits. Every

_m unit of the exchanger according to the invention is at four independent

cd-pending supply circuits connected »with which the unit

cd boards are connected. To complete as possible homogeneity ^ did ensure this exchanger aiteinander comparable ^ ₃ are boxes by the panels are arranged so that two adjacent panels connected to two separate flow circuits

are * In the case shown, everyone feeds Süromungskreia every fourth panel in each unit. Fig. 8 shows the connection between the header pipes 3 and the pipe groups 6. Since this Header pipes in the order 3a, 3b, 3c ,, 3d, 3a, 3b etc. are next to each other, all collecting pipes provided with the same index are connected to a group bearing the same index.

This arrangement ensures a homogeneous Cooling of the gas streams, even if one and the same Flow circuit connected panel arrangement is not fed, while the neighboring panels remain fed.

The steam discharge pipes connected to the header pipes 4 7 are arranged in flat, preferably horizontal groups. Each pipe 7 corresponds to an independent flow circuit and is connected to every fourth vapor collecting pipe by means of connection lines 21 which are branched off from the side facing away from the pipe elements 2, i.e. from the upper part of the headers 4 (fig. 4 and 5).

Pig. 9 shows the connection between the collecting pipes 4 and the pipe sets 7. All the collecting pipes 4a (which correspond to the water collecting pipes 3a) are connected to the same steam pipe 7a via lines 21a. The collecting pipes 4t ·, 4c, and 4d_ are also connected to the pipes 7Jb, 7 £ and 7d via lines 21b_, 21 £ and 23 <1 »

The jacket 22 surrounding each unit extends from the steam collecting tubes 4 to the tube bundles for feeding with water. These dumbbells guide the flow of the heat carrier gas around the pipe elements 1.

The jacket is designed to accommodate a removable 909881/0671

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Cover ο the like. furnished at its, lower and upper ends, so that a tight chamber is created, which is filled with a neutral gas or connected to a conduit of conditioned air can be so that the pipes against during transport or storage up to commissioning of the plant Moisture and dust are protected.

The traga ^ arrangement of the units 5 has

an upper horizontal chord 15 made of bars 25 or the like. Which are braced so that they form rhombuses corresponding to the cross-section of the units, and to which flanges 24 are attached are. This belt rests on the central pillar 16 housed in the space 12 (FIG. 1) and on the supporting shell 29 of the reactor attached brackets 28 or the like .. Each unit is supported at the top by the flanges 24 on which it is attached supported by support elements of the standard panels · In the case of the one shown In this case, it is the steam collecting pipes 4 'which serve as support elements for each panel 1. The flanges 24 are with Notches 26 are provided, in which at the ends of the header pipes 4 (Fig. 10) attached end pieces 27 are used. The notches 26 are designed so that they the distribution of the Samaelrohre 4 to allow two superimposed rows, as stated above, the different depth of two consecutive Rest corresponds to the difference in height between these two rows. The unit tables of one and the same Flanges supporting the unit form the upper part of the hanteis this unit.

Although the exchanger shown is designed for an upward flow of water, it can Of course, also assume the opposite position, u® dasa that

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8AD ORIGINAL

Water flows in an ascending direction while the heat carrier gas flows downwards.

The embodiment shown can be modified without departing from the scope of the invention. So can e.g. the flexible connection lines 17 on the side of the Must be installed, i.e. between the manifolds 4 and the pipes 7 · Likewise, the middle pillar 16 can go through several pillars are replaced, e.g. six pillars arranged at the six corners of the hexagonal interior 12, and the Brackets 28 can through on the perimeter of the hexagonal ring 11 arranged pillars are replaced.

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Claims (1)

Claims 1 ») Heat exchanger with forced circulation, which preferably forms a steam generator, with bundles of straight, vertically arranged tubular elements in which a fluid to be evaporated flows, these tubular elements being accommodated in at least one jacket, in in which a heat carrier flows in the opposite direction to the fluid to be heated, e.g. a gas to be cooled, characterized in that it is characterized by identical adjacent b unit tables (1) are formed, which contain a certain number of identical pipe elements (2) and are combined into separate identical units, each of which forms an elementary exchanger, these units being combined in such a way that that they have the shape of a polygonal ring in a plane perpendicular to the axes of the tubular elements, 80 that on the one hand between the outer contour of the ring and the wall of the Chamber in which the units are housed and, on the other hand, free spaces in the central section of the ring (14 and 12) for accommodating the support arrangement (16) and the * enters the water supply pipes and the steam discharge pipes (10) uew · arise. 2 ·) Heat exchanger according to claim 1, characterized in that the units are combined so that they form a hexagonal ring (11). co ^ ο 3.) Heat exchanger according to claim 1 or 2, j »characterized in that each unit table (1) is marked by a Z ^ flock γοη. Pipe elements (2) is formed, the axes of which in the c on the same level, and which at each end with an ** umpteen manifolds (3 or 4) are connected, the axis of which is in the BAD QRIG'NAL the same plane as the axes of the teaching elements. 4.) Heat exchanger according to one of the claims 1 to 3, characterized in that the pipe elements (2) of each panel with at least one of the collecting pipes (e.g. 3) over flexible connecting lines (17) are connected, the axes of which lie in the same plane as the axes of the pipe elements (2), the pitch of the connections of these connecting lines to the corresponding collecting pipe (3) is smaller than the rope the pipe elements is. '5.) Heat exchanger according to one of the claims - 1 to 4, characterized in that the connecting lines (1?) At least two consecutive opposite knees (18a, 18t)) and symmetrical with respect to one to the Vertical plane (P) going through the cement of the collecting pipes are arranged 6.) Heat exchanger according to one of claims 1 to 5, characterized in that each connecting line (17) in the flow direction of the flow means has a first, second and third rectilinear section (19a, 19]), 19c.), The opening angle between the first and * second portion of the same for all lines of a panel half, while the angle between the second and the third section in each panel half th of the side remote from the ^s ymmetrieebene (F) furthest line to which that _m the plane of symmetry at next lying line increases. to 7 ·) Heat exchanger according to claim 6, characterized a> marked that the third section (19 ©) of each ^ of the two connecting lines connected to the two central tubular elements ^ ₄ connecting lines in the extension of these drilling elements 8.) Heat exchanger according to one of the claims 5 to 7, characterized in that the connecting lines (17) are arranged so that they are in the one of the two at the end of each pipe element (2) lying on the table lie in a limited space. 9 ·) Heat exchanger according to one of claims 5 to 8, characterized in that the connecting lines (17) preferably between the collecting pipe (3) for feeding with the fluid in the liquid phase and the pipe elements (2) are provided. 10.) Heat exchanger according to one of claims 1 to 9, characterized in that the units in section through a plane perpendicular to the axes of the pipe elements Have polygonal shape. 11.) Heat exchanger according to one of the claims 1 to 10, characterized in that the units have the shape of a rhombus (5) in section » _Λ 12 ·) Heat exchanger according to one of claims 1 to 11, characterized in that each unit (5) τοη. a jacket (22) is surrounded, the contour of which corresponds to its own outer contour. 15 ·) Heat exchanger according to claim 11, characterized in that the rhombus-shaped units (5) are formed by sub-units which have the form να »in each ^ rhombus inscribed parallelograms. · SH.) Heat exchanger according to a« der Aam & sweäm - * 1 to 13 »characterized in that the ftmmmlrefeam (4 $ fir ■ the removal of the vaporous fluid * τα » - * e, inaiKlerl leg end consecutively «f * £ * lJi Ct I« ** wsl BAD ORlQfNAL the same unit are vertically offset from one another in such a way that they are in at least two rows at different heights where the headers of one row correspond to the spaces between the headers of another row 15.) Heat exchanger according to one of the claims 1 to 14, characterized in that several independent Flow circuits provided for the fluid to be heated are, for example, four flow circuits, each of which has four adjacent panels of one and the same unit (5) connected in this way are that two adjacent panels are connected to two different circuits 16.) Heat exchanger according to one of claims 1 to 15 »characterized in that the feed pipes of the header pipes (3) for the liquid are in the form of superposed flocks (6a, 6b, 6c, Sd) of pipes which are bent in a hairpin shape on themselves where each family corresponds to a given ossification circle. 17.) Heat exchanger according to claim 16, characterized in that the superimposed groups * are provided are that the tubes of two successive families have different directions. 18 ·) Heat exchanger according to claim 16 and 17, characterized in that the straight pipe elements in each pipe section (6a, 6b_ etc.) parallel to the sides of the den outer outline of the unity forming tielecks are 19 ·) Exchanger according to claim 16 to 18, characterized in that the outline of the pipe is sharp Outline corresponds to the unit. 20.) Heat exchanger according to claim 16 to 19, 909881/0671 characterized in that, in the case of a unit with a rhombus-shaped outline, the drilling elements of the superposed pipe layers (6a, 6b, etc.) to the sides of the rhombus are parallel. 21 ·) Heat exchanger according to one of the claims 1 to 20, characterized in that each unit (5) is connected to steam discharge pipes (7) which are flat, preferably form horizontal groups 22 ·) Heat exchanger according to one of claims 1 to 21, characterized in that each steam discharge pipe (7a, 7b_ etc.) with the corresponding manifold (4a., 4b etc.) is connected by pipes (21a, 21b, etc.) which are connected to the collecting pipe on the side facing away from the pipe elements are connected. 23 ») Heat exchanger according to one of the claims 1 to 21, characterized in that the exchanger forming a generator is preferably arranged so that the Flow of the flow medium to be evaporated takes place in an ascending direction. 24 ·) Heat exchanger according to one of claims 1 to 23, characterized in that the support order of the Units has an upper horizontal belt (15) which is formed by braced beams (25) on which. Flanges (24) are attached, which the upper parts of the jacket (22) form, and on which the support elements (27) of the unit board (1) rest with their upper rope. 25) Heat exchanger according to one of claims 1 to 14, characterized in that the unit panels (1) from the support arrangement by means of its upper header pipes (4) 909881/067 1 8AO ORIGINAL be worn. . . 26 ·) Exchanger according to claim 24 and 25, characterized characterized in that the plansche (24) is provided with notches (26) are, in which the ends (27) of the upper header pipes (4) engage. 27 ·) Heat exchanger according to claim 24, characterized in that the beams of consoles (28), pillars o- «like. are carried, which are arranged on the circumference and / or in the central rope of the support arrangement. 28.) Heat exchanger according to one of claims 1 to 27 »characterized in that the wear ο rdnung in its central section has a single pillar (16) coaxial with the wreath 909881/067 *