EP1876391A1 - Heat Exchanger and Method for its Fabrication - Google Patents

Abstract

The heat exchanger (1) has a channel (3) and heat exchanger tubes (4) in a longitudinal direction, where a medium to be heated and a heating medium are flowable, respectively. The tubes are arranged between a distribution chamber (6) and a collection chamber (7), and are connected with the distribution and collection chambers over tube bottoms. The tubes are arranged as a circular tube bundle (5) with an unobstructed central region (10), and an outer redirecting unit is provided in the channel to produce cross-flow, which is directed to the central region, in the medium to be heated. An independent claim is also included for a method for manufacturing a heat exchanger.

Description

The present invention relates to a heat exchanger and a method for its production. In particular, the heat exchanger is a steam-heated reheater having a channel extending in a longitudinal direction through which a medium to be heated can flow. The medium to be heated is usually water vapor, but it can be generally suitable media such as gases, liquids or mixtures thereof.

In the channel a plurality of heat exchanger tubes is arranged, which also extend in the channel longitudinal direction and which can be traversed by a heating medium. The heating medium is usually also water vapor, which, however, has a higher temperature than the medium to be heated. But here, too, it can generally be appropriately suitable media such as gases, liquids or mixtures thereof.

In the known reheaters the steam to be heated flows in the channel in the channel longitudinal direction, along the outside of the heat exchanger tubes and is heated by the hotter heat exchanger tubes. The heat exchanger tubes are arranged as a tube bundle between at least one distribution chamber and at least one collecting chamber and connected via tube sheets with the respective chambers. In the tube bundles, which usually cover a circular base area, the heat exchanger tubes are so closely spaced from one another that the medium to be heated can enter between them and, in the further course, can flow along the tubes in the longitudinal direction. In contrast, the heating medium flows from the distribution chamber into the heat exchanger tubes and leaves them in the collection chamber. The tubesheets are solid components, in which the heat exchanger tubes are held in corresponding recesses.

These known longitudinally flowed tube bundle heat exchangers were used in particular in the first generation of German nuclear power plants as Wasserabscheider reheater. Such a known Wasserabscheider reheater is for example in the patent DE 3544517 C1 described. However, these known Wasserabscheider reheaters have relatively high pressure losses due to design.

The invention is therefore based on the object to provide a heat exchanger with significantly reduced pressure losses and a manufacturing method for such a heat exchanger.

The solution of this object is achieved with a heat exchanger having the features of claim 1 and with a manufacturing method having the features of claim 31.

According to the invention, therefore, it is a heat exchanger, in particular steam-heated reheater of the type described above, but which differs from the conventional types in that the heat exchanger tubes are arranged as a ring-shaped tube bundle with a non-central area. Under annular is understood in this context not only an annular tube bundle. It can also be elliptical or angular rings. It is crucial that this annular tube bundle has in its center a central region which is not drilled. Thus, the bundle-shaped, although dense, but still spaced next to each other arranged heat exchanger tubes with the unthreaded central region form a channel longitudinally extending, located in the interior, flow channel-like area. In addition, according to the invention, at least one outer deflecting means is provided according to the invention for achieving a transverse flow in the medium to be heated, directed at the non-centered central area. As a result, the medium to be heated sweeps transversely through the deflecting means from the outside to the inside over the heat exchanger tubes and not along the heat exchanger tube in the longitudinal direction as in the case of the generic heat exchangers. Due to the design of the tube bundle as a transversely flowed, annular tube bundle with a non-centered center, the pressure loss compared to longitudinally flow-through tube bundles with a centered hole can be reduced to approximately 25% of the previous values. The resulting power gain can be up to 8 MWe for a 1300 MWe nuclear power plant.

Conveniently, the unthreaded central region of the tube bundle has a minimum width which is greater than the maximum ring thickness of the tube bundle. Under the maximum ring thickness of the tube bundle ring is in a symmetrical circular ring half the difference between outside and Inner diameter of the annulus to understand. This ratio value ensures that there is a sufficiently large, central, untouched area in which the medium to be heated, which enters the central area across the heat exchanger tubes, can change its flow direction without major friction losses. It is therefore not hindered in his direction change by running in the channel longitudinal direction heat exchanger tubes.

In this case, the outer deflection means may be annular, wherein it is particularly preferably at least partially conically shaped. Thus, the outer deflection means generates a uniformly deflected flow in the channel and, in particular in the case of a symmetrical arrangement in relation to the channel longitudinal axis, also a symmetrical deflection. This means that the medium to be heated with respect to the channel longitudinal axis flows from all sides equal to the non-central area. The quasi-annular streams, which are directed in each case towards the center, therefore flow toward one another in the radial direction and meet in the non-centered central region of the tube bundle, where they deflect each other in the direction of the channel longitudinal axis. In the flow direction behind the outer deflecting means, a flow aligned in the channel longitudinal direction then arises in the non-central region of the tube bundle.

Conveniently, the outer deflecting means extends from a channel wall of the channel inwardly to at least the outer peripheral portion of the tube bundle, preferably even to its non-centered central portion and slightly beyond. This has the advantage that the outer deflecting means then ensures that there is a transverse flow over the individual heat exchanger tubes of the tube bundle and the transverse flow only changes in the non-central area into a longitudinal flow.

Preferably, the outer deflection is attached to the channel wall. Thus, it is ensured that the medium to be heated can not flow around the outside of the outer deflection means. This would have the disadvantage that parts of the flow would not be covered by the outer deflection. In addition, the deflection can be well attached to the channel wall, since this is usually sufficiently stable to carry the introduced from the outer deflection forces.

In a particularly preferred development of the heat exchanger, at least one of the chambers, ie either the collection chamber or the distribution chamber, has a tube plate which has an annular, drilled bottom region. The Berohrungsmuster this drilled floor area corresponds to that of the tube bundle ring, since the tubes are passed through the tubesheet and held by the tubesheet in the heat exchanger. The drilled ground area surrounds one mossy ground area, where the mossy ground area is thinner than the drilled ground area. The drilled floor area thus serves to hold the heat exchanger tubes in order to connect them to the respectively adjoining chamber and the non-drilled floor area serves for sealing. At the same time, the pristine floor area has greater elasticity than the drilled floor area. So it can be made of a softer material with a lower modulus of elasticity than the drilled area.

Preferably, the untapped floor area is made thinner than the drilled floor area. This measure can supplement or replace the execution of the non-ground area of softer material. In particular, when both the tube plate of the collection chamber and the tube plate of the distribution chamber are of similar design, the inventive embodiment of the tube plates has the advantage that arrival or Abfahrvorgänge the heat exchanger according to the invention are much faster possible than in generic conventional heat exchangers. The heat exchanger and thus the entire system or the power plant can therefore be operated much more flexible.

This is due to the fact that unfavorable stresses in the tubesheets are avoided or reduced by the non-drilled floor area. Thus, a large, untapped and thick-walled area of the tube bottom is avoided by the thinner running, bottom area. Since the bored area is warmed or cooled very quickly due to the enforcement with the heat exchanger tubes at each startup or shutdown, these temperatures would be very slow in an unidirectional inner midsize area, since this area represents a large mass, which only by heat conduction would be heated within the tube sheet. This leads to temporary temperature differences between the drilled and non-drilled areas and thus to thermal stresses that limit the number and gradient of the startup and shutdown processes. If instead a thinner or less rigid component is used for the non-prone area, either less thermal stress can be set or, as this area becomes more easily deformed, it will degrade better.

This effect is further enhanced when the mossy floor area has a domed area. The curvature can be done with a constant radius or a variable radius. It is only important that the deformability of the non-drilled soil area is increased by this shaping so that as few stresses as possible are introduced from the non-drilled soil area into the drilled soil area. Preferably, the domed Regions of both tubes in the same direction bulged, it is useful if the curved portion of the tube bottom of the collection chamber is bulged in the direction of the Vereilkammer.

Also, a vent may be arranged with a suction in the collection chamber, which serves for the extraction of, for example, inert gases from the heating medium. In this case, the suction opening should preferably be in the region of the curved floor area. As a result, the space of the collecting chamber is increased, which lies below the intake opening. This space can be used in certain embodiments of the heat exchanger for the collection of condensate liquid, which accumulate on the condensate, the inert gases. Now, if this space is increased, results in a larger buffer for itself accumulating condensate, without thereby reducing the space for the extraction of inert gases.

Particularly preferably, the suction opening of the vent between maximum bulge of the curved bottom portion and the drilled bottom portion of the tube bottom of the collection chamber is arranged. Then the suction is above the tube sheet, ie higher than usual. This has the advantage that the space for collecting condensate in the collection chamber again increases compared to conventional collection chambers.

Conveniently, the untapped floor area consists of a press plate. It is also advantageous if the drilled floor area consists of a forged part. The press plate can be easily formed and is inexpensive, while the forged part has a high strength, which is particularly advantageous for the secure holding of the tubes. This is expediently a forged steel.

The outer deflection means preferably has a expansion compensator for compensating for different strains. Such differences in expansion may arise, for example, from the different changes in length of the deflection means or the heat exchanger tubes with respect to the channel walls. In other words, the expansion compensator is a correspondingly suitable compensation spring which prevents excessive loading of the deflection means. The expansion compensator therefore preferably has a ring plate with shafts running coaxially to its longitudinal axis. It is therefore an annularly curved corrugated sheet, the waves either parallel to the longitudinal axis or transverse to the longitudinal axis, that is radial, run. In any case, it is ensured by such an arrangement that by stretching or compressing the waves sufficient deformation is available to ensure differences in expansion between the deflection and the channel wall and the heat exchanger tubes.

While most components of the heat exchanger, in particular the deflection means and the heat exchanger tubes, are made of carbon steel, the expansion compensator is preferably made of stainless steel. This takes account of the increased stresses, in particular of many deformation changes under permanent steam stress.

In a further development of the heat exchanger according to the invention at least one inner deflection means for achieving a cross-flow in the medium to be heated is arranged in the non-central area of the tube bundle. This can ensure that a flow of the medium to be heated, directed from the outer deflecting means into the inner, non-centered central area, is again directed back out of the non-drilled central area towards the channel wall. Therefore, inner and outer deflection means are preferably arranged alternately along the channel longitudinal axis. This results in a serpentine, meandering flow through the heat exchanger, which preferably has at least one to four transversely to the channel longitudinal axis extending flow paths.

Conveniently, the inner deflection means extends at least over the entire non-central area of the tube bundle. It may be a disc in the simplest embodiment. This can be made very good and easy.

In a further preferred development, the heat exchanger tubes are supported in their course by at least one annular support means transversely to their longitudinal axes. This prevents excessive deformation or vibration of the heat exchanger tubes due to the cross flow of the medium to be heated. In addition, a buckling of individual heat exchanger tubes is prevented due to larger normal stresses. In this case, the width of the support means approximately correspond to the ring width of the tube bundle, since it then also contributes to a deflection of the flow across the heat exchanger tubes. In addition, the support means can also protrude slightly beyond the ring width of the tube bundle both inwardly and outwardly to be more stable and redirect even more parts of the flow of the medium to be heated.

Conveniently, a deflection is attached to at least one support means. This has the advantage that one already uses existing support means for fixing the deflection.

Preferably, at least one support means and / or a deflection means is attached to at least one heat exchanger tube. Thus, the support means or deflection always remains fixed in its position relative to the heat exchanger tube. However, in the case of an outer deflecting means fixed to the channel wall, this means that it has an expansion compensator which determines the differences in expansion the heat exchanger tubes with respect to the channel wall compensates to prevent damage to the outer deflection.

Preferably, at least one support means and / or a deflection means has at least one recess for the passage of a heat exchanger tube. That is, the heat exchanger tube is passed through the support means or the deflection means, it being expedient if all the heat exchanger tubes are performed by the support means or deflection means. If all the heat exchanger tubes are performed by their own recesses, then the support means or the deflecting means supports the heat exchanger tubes against each other. Also, the support means or the deflection can be connected in the region of the recesses with the heat exchanger tubes.

If, in the case of an outer deflection means, the recesses are designed such that the heat exchanger tubes do not or hardly touch the deflection means, the deflection means can be fastened directly to the channel wall without a expansion compensator. Then thermal expansion of the heat exchanger tubes can not be transferred to the deflection. It can therefore not come to harmful voltages between the deflection and the channel wall.

Preferably, the heat exchanger tubes finned tubes. Thus, the surface of the heat exchanger tubes flushed around by the medium to be heated is increased. Preferably, however, it is low-finned finned tubes, since the weight of the heat exchanger can be reduced as a whole by their use. This is especially advantageous during transport and during assembly. It is also expedient if the ribs of the heat exchanger tubes do not run parallel to the longitudinal axis of the tubes. This reduces the flow resistance of the heat exchanger tubes and the deflection of the flow transversely to the tube longitudinal axis is supported by the surface of the tubes.

According to the invention, the above-mentioned object is also achieved by a method for producing a heat exchanger, in which an existing heat exchanger of conventional design is rebuilt. In this case, an existing tube bundle is removed in a first step, in a second step, the original tubesheets are rebuilt to the previously described tube sheets according to the invention with annularly bored bottom portion, and in a third step, an annular tube bundle with new heat exchanger tubes and at least one deflection means to achieve Cross-flow installed in the heat exchanger. The production method according to the invention is therefore based on the astonishing knowledge that it is possible to use a heat exchanger through which a heat exchanger flows longitudinally and substantially parallel to the channel axis To be able to use output product for the production of a completely different flowed through heat exchanger. Accordingly, the conversion succeeds without setting a larger footprint. Therefore, it is possible to produce water separators and reheaters of the first generation to water separators and reheaters according to the invention design on the spot, ie in the power plant. In such a case, therefore, the water separator and reheater of the first generation is the starting product for the production of the heat exchanger according to the invention, wherein its outer shell, ie channel wall, essentially remains and only the interior is replaced.

In this case, the original tubesheets are rebuilt against tube plates, as described above, with an annularly drilled bottom area. This is particularly successful when it is found during the upgrade of a heat exchanger that the original tube sheet or the original tube plates have little signs of wear, so a focus mainly on the heat exchanger tubes. In that case, only the area of the tubesheet that has subsequently been milled out must be cut out and replaced by a more elastic or thinner floor area. This can be done on the spot in the power plant and also has the advantage that you do not have to completely rebuild the very expensive tube sheets.

In an expedient development of the method according to the invention, the new heat exchanger tubes are installed as a preassembled package together with at least one support means and / or deflection means and / or at least one tubesheet. This has the advantage that the internals of a heat exchanger according to the invention can be produced under optimal production conditions in a workshop.

Fig. 1:

einen Querschnitt durch ein erstes Ausführungsbeispiel eines erfindungsgemäßen Wärmetauschers;

Fig. 2:

die Draufsicht auf den im Fig. 1 gezeigten Schnitt A-A;

Fig. 3:

einen Querschnitt eines Kreuzungspunktes von Umlenkmittel und Wärmetauscherrohr bei dem das Umlenkmittel nicht am Wärmetauscherrohr befestigt ist;

Fig. 4:

einen Querschnitt eines Kreuzungspunktes von Umlenkmittel und Wärmetauscherrohr bei dem das Umlenkmittel am Wärmetauscherrohr befestigt ist;

Fig. 5:

eine Draufsicht auf den in Fig. 4 gezeigten Kreuzungspunkt;

Fig. 6:

eine vergrößerte Darstellung des in Fig. 4 gezeigten Details B;

Fig. 7:

einen Querschnitt durch ein zweites Ausführungsbeispiel eines erfindungsgemäßen Wärmetauschers;

Fig. 8:

einen Querschnitt durch ein drittes Ausführungsbeispiel eines erfindungsgemäßen Wärmetauschers;

The invention will be explained in more detail with reference to embodiments shown in the drawings. In it show schematically:

Fig. 1:

a cross section through a first embodiment of a heat exchanger according to the invention;

Fig. 2:

the top view of the section shown in Figure 1 AA.

3:

a cross section of a crossing point of deflection and heat exchanger tube in which the deflection means is not attached to the heat exchanger tube;

4:

a cross section of a crossing point of deflecting means and heat exchanger tube in which the deflecting means is fixed to the heat exchanger tube;

Fig. 5:

a plan view of the crossing point shown in Figure 4;

Fig. 6:

an enlarged view of the detail B shown in Figure 4;

Fig. 7:

a cross section through a second embodiment of a heat exchanger according to the invention;

Fig. 8:

a cross section through a third embodiment of a heat exchanger according to the invention;

The inventive heat exchanger 1 shown in Fig. 1 is a water separator reheater for a German nuclear power plant of the first generation, which can be installed in place of a conventional Wasserabscheider reheater because it has its outer dimensions. Therefore, this heat exchanger 1 has a channel 3 extending in a longitudinal direction 2 in which a plurality of heat exchanger tubes 4 are arranged as a tube bundle 5 between an uppermost distribution chamber 6 and a lower collection chamber 7. The heat exchanger tubes 4 of the tube bundle 5 are connected via a first tube plate 8 with the distribution chamber 6 and a second tube plate 9 with the collection chamber 7 and are each held by them in their position in the heat exchanger 1.

The distribution chamber 6 in this case has a Heizdampfeintrittsstutzen 36 through which the heating steam is introduced into the distribution chamber 6 and from there into the heat exchanger tubes 4. In contrast, the collection chamber 7 has a Heizdampfkondensataustritt 37, is discharged through the leaking from the heat exchanger tubes 4 condensate and some of the residual steam. In addition, a manhole 38 is provided both in the distribution chamber 6 as in the collection chamber 7, through which, for example, maintenance personnel can enter into the chambers 6 and 7 for maintenance.

According to the invention, the tube bundle 5 extending between the distribution chamber 6 and the collection chamber 7 is designed in the form of a ring with a non-centered central region 10, as can also be seen in FIG. In the present case, it is an embodiment of the tube bundle 5 with a substantially circular base. The width of the non-centered central region 10 of the tube bundle 5 corresponds to the inner diameter of the annular tube bundle 5. The is about five and a half times wider than the ring thickness, which is chosen consistently strong over the entire ring.

In the channel 3 of the heat exchanger 1, an outer deflection means 11 is also installed. This is a partially cone-shaped steel sheet, which extends from the channel wall 12 inwardly to the inner, non-centered central region 10. Here, the deflection means 11 is constructed so that at the upper edge of the cone-shaped portion 13, an annular, flat plate 14 connects, while at the bottom of the cone-shaped portion 13, a compensator 15 is arranged.

The compensator 15 is here a cylindrically curved ring made of a stainless steel corrugated sheet whose own, central longitudinal axis is arranged coaxially to the channel longitudinal axis 2. Accordingly, the compensator 15 compensates for differences in length between the deflection means 11 and the channel wall 12, especially in this direction. Such differences in length may result due to different temperatures in the heat exchanger tubes 4 and the channel wall 12. Since the outer deflection means 11 is attached to both the heat exchanger tubes 4 as well as to the channel wall 12, these changes in length without the compensator 15 could lead to a rupture of the deflection means 11.

In the embodiments shown in FIGS. 1 and 8, the tube plates 8 and 9 of both the distribution chamber 6 and the collection chamber 7 are each constructed so as to have a drilled bottom region 16 and a non-drilled bottom region 17. In the exemplary embodiment shown in FIG. 7, the tube plate 9 of the collecting chamber 7 is designed as an open ring in the interior, which has only one drilled bottom region 16. Regardless of the design of the inner portion, the drilled bottom portion 16 in all embodiments is a solid and forged carbon steel ring having a plurality of bores in each of which a heat exchanger tube 4, for example, by hydraulic pipe inside expansion with external edge welding, is fixed. The pattern of the bores corresponds in each case to the bore pattern of the tube bundle 5. The non-tapped regions 17 are embodied in the exemplary embodiments of FIGS. 1 and 8 as arched pressing plates. This has the advantage that the press plates 17 are heated quickly and deform so that no appreciable stresses are introduced into the drilled bottom regions 16. Therefore, in the heat exchangers 1 according to the invention faster startup and shutdown than previously possible, so that they allow a more flexible operation of the entire system.

In the embodiment shown in Fig. 1, a vent 18 is arranged in the collecting chamber 7, the suction opening 19 is above the drilled bottom portion 16 and below the maximum bulge of the unrooted bottom 17. This intake 19 is thus higher arranged as in conventional heat exchangers, which creates more space for the collection of condensate or for above the condensate accumulating inert gases. Thus, the buffering effect of the heat exchanger according to the invention increases in an advantageous manner.

Furthermore, the heat exchanger 1 shown in Fig. 1 and Fig. 2 eight Stützmitte! 20 on. These are perforated metal rings whose hole pattern correspond to that of the tube bundle 5. In the recesses 21, the heat exchanger tubes 4 penetrate the support means 20.

The heat exchanger tubes 4 are finned tubes which are provided with ribs 22 at their outer peripheral sides. As can be seen, for example, from FIG. 3, these are low-finned finned tubes. The ribs 22 are thus relatively short and closely spaced. In this case, the ribs 22 extend transversely to the tube longitudinal axis 23, which is substantially parallel to the channel longitudinal axis 2, that is, without greater deviation relative to the angular position of the channel longitudinal axis 2 extends. This shape of the rib reduces the flow resistance and makes the tubes 4 lighter.

In the embodiment shown in Fig. 3 of a crossing point between a heat exchanger tube 4 and the outer baffle 11 is a node that allows the omission of a compensator 15 on the baffle 11. This is because the baffle 11 is not attached to the heat exchanger tube 4. Rather, here is the recess 21 wider than the outer diameter of the heat exchanger tube 4. So that the deflecting means 11 can not be wedged or clamped to the ribs 21 of the heat exchanger tube 4, a the deflector 4 associated penetration area 24 of the outer skin of the heat exchanger tube 4 is made untouched and smooth. This penetration region 24 is longer than the deflecting means 11 is thick in order to be able to act even when changing the relative position of the two components.

In Fig. 4, an alternative embodiment of such a crossing region is shown. Here, the deflection 11 is attached to the heat exchanger tube 4 via half-shell-shaped mounting shoes 25. The half-shell-shaped fastening shoes 25 are welded to the deflecting means 11 and there to the upper ring 14 and have on their facing the heat exchanger tube 4 inside a the rib pattern of the heat exchanger tube 4 corresponding rib structure. Therefore, the ribs 26 of the fastening shoes 24 engage in the ribs 21 of the heat exchanger tube 4 and prevent twisting or displacement of the deflection means 11. In such an embodiment, the deflection means 11, when it is to be connected to the channel wall 12, have a compensator 15 because otherwise it is different Thermal expansions of the channel wall 12 and the heat exchanger tubes 4 would cause damage to the deflection means 11.

During operation, the water separator reheater 1 shown in FIG. 1 flows through steam to be heated. In this case, the steam to be heated 27 enters the reheater 1 in the inlet region 28 and initially flows vertically upward toward the outlet opening 31. In the region of the collecting chamber 7, the steam to be heated 27 is directed by a conical taper 29 of the channel 3 to the heat exchanger tubes 4. As a result, the steam 27 to be heated flows transversely across the heat exchanger tubes 4 of the annular tube bundle 5 into the inner, unthreaded central region 10. Due to the symmetrical in this area embodiment of the channel wall 12 of the heat exchanger 1 meet there in opposite directions inwardly flowing cross flows each other and divert against each other so that the steam 27 rises vertically in the sequence. Since this is done according to the invention in the non-central area 10, the friction loss is reduced in this heat exchanger compared to a conventional tube bundle with a central bored area. In addition, the heat exchanger 1 according to the invention in addition to an outer baffle 11, the other steam strands 30 deflects so that the channel 3 is also not substantially in the sequence but longitudinally meandering transversely.

Since the deflecting means 11 is arranged below an outlet opening 31, the steam to be heated 30, after being directed by the deflecting means 11 onto the non-central area 10, flows first inwardly and then laterally outwards towards the outlet opening 31, over which then heated steam leaves the reheater 1. To even out the flow of the heated steam, a vertically extending perforated plate 39 is arranged in front of the outlet opening 31. This perforated plate 39 is attached to support rings 20.

Since the outlet opening 31 is arranged slightly below the upper distribution chamber 6, above the deflection means 11, some steam strands 32 in particular flow vertically upward, if they have a large lateral distance to the outlet opening 31. By the side over the heat exchanger tubes 4 projecting support plates 20, however, this longitudinal flow is redissolved in the region of the annular tube bundle 5, so that also forms a meandering cross flow above the deflection means 11. However, since each steam train must flow through the tube bundle 5 at least twice transversely to the channel longitudinal axis 2, one speaks in the embodiment of the heat exchanger 1 shown in FIG. 1 of a two-way heat exchanger.

FIGS. 7 and 8 show two further exemplary embodiments of heat exchangers 1 according to the invention, in which the steam, as can be seen in FIG. 7, covers at least three transverse paths over the heat exchanger tubes 4 or, as shown in FIG. 8, at least four times the heat exchanger tubes 4 must cross. This is achieved in both embodiments in that outer, partially conically shaped deflection 11 are arranged in alternation with inner deflection means 33 along the channel longitudinal axis 2. In the embodiment shown in FIG. 7, a single inner deflection means 33 and an outer deflection means 11 arranged above it are sufficient to achieve three transverse flow paths, as symbolized by the arrow 34. In this case, the steam to be heated 27 occurs centrally in the middle of the channel 3, since here the collection chamber located below 7 is designed annular.

In the embodiment shown in Fig. 8, the steam to be heated 27 enters as an annular jet between the cylindrical outer side of the collecting chamber 7 and the channel wall 12 a. Since in this embodiment, too, only an inner deflection means 33 is provided, which, however, is located between two outer deflection means 11, the steam to be heated 27 has to pass across the annular tube bundle 5 at least four times before it leaves the heat exchanger 1 via the outlet opening 31 as symbolized by the arrow 35. This is called a four-way heat exchanger.

Claims (32)

Heat exchanger (1), in particular steam-heated reheater, having a channel (3) extending in a longitudinal direction (2) through which a medium to be heated flows and a multiplicity of heat exchanger tubes (4) arranged therein and extending in the channel longitudinal direction (2). which can be traversed by a heating medium and which are arranged as a tube bundle (5) between at least one distribution chamber (6) and at least one collecting chamber (7) and connected to the respective chambers (6, 7) via tube sheets (8, 9),
characterized,
in that the heat exchanger tubes (4) are arranged as a ring-shaped tube bundle (5) with a non-tapped central region (10) and in that at least one outer deflecting means (11) in the channel (3) for achieving a transverse flow directed towards the non-tapped central region (10) Medium is provided. Heat exchanger according to claim 1,
characterized,
in that the non-tapped central region (10) of the tube bundle (5) has a minimum width which is greater than the maximum annular thickness of the tube bundle (5). Heat exchanger according to claim 1 or 2,
characterized,
that the outer deflection means (11) is annular. Heat exchanger according to one of the preceding claims,
characterized,
that the outer deflection means (11) is partially conically shaped. Heat exchanger according to one of the preceding claims,
characterized,
in that the outer deflection means (11) extends inwardly from a channel wall (12) of the channel (3) to at least the outer peripheral region of the tube bundle (5), preferably to its non-centered central region (10). Heat exchanger according to one of the preceding claims,
characterized,
that the outer deflection means (11) is fixed to the duct wall (12). Heat exchanger according to one of the preceding claims,
characterized,
in that at least one of the chambers (6, 7) has a tube bottom (8, 9) which has an annular, drilled bottom region (16) whose bore pattern corresponds to the tube bundle (5) and which surrounds a non-drilled bottom region (17) the untapped floor area (17) has a greater elasticity than the drilled floor area (16). Heat exchanger according to one of the preceding claims,
characterized,
unberohrte that the bottom portion (17) is thinner than the piped floor area (16). Heat exchanger according to one of the preceding claims,
characterized,
unberohrte that the bottom portion (17) has a curved region. Heat exchanger according to one of the preceding claims,
characterized,
that the tube bottom (8) of the distribution chamber (6) and the tube plate (9) are formed similar to the collection chamber (7). Heat exchanger according to one of the preceding claims,
characterized,
that the curved areas of both tube sheets (8, 9) are curved in the same direction. Heat exchanger according to one of the preceding claims,
characterized,
in that the curved region of the tube bottom (9) of the collecting chamber (7) is bulged in the direction of the distribution chamber (6). Heat exchanger according to one of the preceding claims,
characterized,
in that a vent (18) having a suction opening (19) is arranged in the collecting chamber (7), wherein the suction opening (19) is located in the region of the curved area. Heat exchanger according to one of the preceding claims,
characterized,
in that the suction opening (19) of the vent (18) is arranged between maximum bulging of the curved area and bored bottom area (16) of the tube bottom (9) of the collecting chamber (7). Heat exchanger according to one of the preceding claims,
characterized,
that the untapped floor area (17) consists of a press plate. Heat exchanger according to one of the preceding claims,
characterized,
that the drilled floor area (16) consists of a forged part. Heat exchanger according to one of the preceding claims,
characterized,
in that the outer deflection means (11) has a expansion compensator (15) for compensating for different strains. Heat exchanger according to one of the preceding claims,
characterized,
in that the expansion compensator (15) has a ring plate with corrugations extending coaxially to the longitudinal axis thereof. Heat exchanger according to one of the preceding claims,
characterized,
that the expansion compensator (15) is made of stainless steel. Heat exchanger according to one of the preceding claims,
characterized,
in that at least one inner deflecting means (33) is arranged in the unthreaded central region (10) of the tube bundle (5) for achieving a transverse flow in the medium to be heated. Heat exchanger according to one of the preceding claims,
characterized,
in that the inner deflecting means (33) extends at least over the entire non-central area (10) of the tube bundle (5). Heat exchanger according to one of the preceding claims,
characterized,
that the inner deflection means (33) is a disc. Heat exchanger according to one of the preceding claims,
characterized,
in that the heat exchanger tubes (4) are supported in the course of at least one annular support means (20) transversely to their longitudinal axes (23). Heat exchanger according to one of the preceding claims,
characterized,
that the width of the support means (20) corresponds approximately to the width of the annular tube bundle (5). Heat exchanger according to one of the preceding claims,
characterized,
that at least one support means (20) comprises a deflection means (11, 33) is attached. Heat exchanger according to one of the preceding claims,
characterized,
in that at least one support means (20) and / or deflection means (33) is fastened to at least one heat exchanger tube (4). Heat exchanger according to one of the preceding claims,
characterized,
in that at least one support means (20) and / or a deflection means (33) has at least one recess (21) for passing through a heat exchanger tube (4). Heat exchanger according to one of the preceding claims,
characterized,
in that outer deflection means (11) and inner deflection means (33) are arranged alternately along the channel longitudinal axis (2). Heat exchanger according to one of the preceding claims,
characterized,
that the heat exchanger tubes (4) finned tubes, preferably low-finned tubes are ribs. Heat exchanger according to one of the preceding claims,
characterized,
that the ribs (22) extend transversely to the longitudinal axis (23) of the heat exchanger tube (4). Method for producing a heat exchanger (1) according to one of the preceding claims, in which an existing heat exchanger of conventional design is rebuilt, in which in a first step an existing tube bundle is removed, in a second step the original tube plates to tube plates (8, 9) according to one of claims 7 to 16 are rebuilt with ring-bored bottom portion (16) and in a third step, an annular tube bundle (5) with new heat exchanger tubes (4) and at least one deflection means (11, 33) are installed in the heat exchanger to achieve a cross-flow , Method according to claim 31,
characterized,
in that the new heat exchanger tubes (4) are installed as a preassembled package together with at least one support means (20) and / or deflection means (11, 33) and / or at least one tubesheet (8, 9).

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