Condenser

Abstract

The invention relates to a condenser for condensing a vaporous fluid, preferably a condenser designed on the church window principle. The condenser comprises at least one bundle (10) with a multiplicity of tubes (12) arranged parallel to one another, the bundle being subdivided into an upper sector (16) and a lower sector (14). The tubes have a first fluid flowing through them and the vaporous fluid flowing around them. A condensate discharge element is arranged in the bundle between the upper sector (16) and the lower sector (14). The condensate discharge element may be designed as a condensate discharge plane (60) or else as a condensate discharge duct (80).

Description

[0001] The invention relates to a condenser, in particular a steam condenser for use in a steam turbine plant.

[0002] Condensers for condensing a vaporous fluid are employed in many ways in industry. Thus, for example in the chemical industry, condensers for condensing a wide variety of fluids are often used in conjunction with reaction columns.

[0003] However, a very important area of use for condensers is also in steam turbine plants, particularly of power stations. In the last-mentioned application, as a rule, one or more condensers are arranged in the flow path of the working fluid of the steam turbine process at the outlet of the steam turbine or, if a plurality of steam turbines connected in series are used, downstream of the steam turbines. The steam normally comes from an evaporator (boiler of the steam turbine plant) and subsequently at the same time discharging energy, flows through the steam turbine and ultimately into the condenser. In the condenser, heat is extracted from the steam by heat exchange with a cooling fluid, in order to condense the steam again. The condensate is subsequently supplied to the evaporator once again. The cyclic process of the steam turbine plant is thus closed on itself. In addition to the components mentioned, other components (such as, for example, a heat exchanger and, particularly in the case of combined gas and steam turbine plants, additional further heat exchangers) are often arranged in the flow path of the working fluid.

[0004] Water or water vapor is mostly used as the working fluid in steam turbine plants. As a rule, water is also used for cooling. The invention is described below in connection with steam turbine plants in which water or water vapor is used as the working fluid and water is likewise also used as the cooling fluid. However, this reference is not intended to restrict either the general idea of the invention or the use of other fluids within the meaning of the invention.

[0005] The condenser arranged in a steam turbine plant constitutes a very important component of the steam turbine process and determines the cyclic processing parameters and therefore also the efficiency. Thus, the outlet pressure at the outlet from the steam turbine is set as a direct function of the pressure loss of the fluid (here, for example, steam) when it passes through the condenser. The fluid can therefore also expand only up to this output pressure in the steam turbine, with the result that the discharge of energy from the fluid to the turbine and therefore also the efficiency of the turbine are limited. For this reason, attempts have long been made to provide condensers which bring about as low a steam-side pressure loss as possible, so that a higher mean heat transition coefficient is achieved. However, other parameters must be taken into account at the same time in the design of a condenser. In particular, the construction volume of a condenser is often limited. Moreover, in view of the production costs of a condenser, it is also uneconomical, as a rule, to design a condenser with an excessively large volume, that is to say with long tubes and/or a large number of tubes, even though the lower steam flow velocity established at the same time would lead to a lower pressure loss. On the other hand, however, in the latter case the pumps feeding the cooling fluid would also have to provide a higher delivery.

[0006] A very important criterion within the framework of a basic design of a condenser is, in particular, also the possibility of using the condenser for different operating and power output states of a plant (full load, part load) and also use in different plants with different power output requirements.

[0007] For these reasons, the concept of the modular makeup of a condenser was developed, which is known in the specialized literature by the term “Church Window Bundle”. A condenser designed according to this concept consists, as a rule, of a plurality of (tube) bundles, each bundle consisting of a multiplicity of individual tubes. In this context, the exact number and arrangement of the tube bundles were developed with a view to a minimal pressure loss of the inflowing and condensing steam. The tube bundles can be developed in advance in standardized dimensions. Only the number of necessary bundles of a condenser and the length of the tubes vary, depending on the respective application and the necessary power output or throughput. The diameter of the tubes may also be varied within particular limits. The individual design of a condenser can therefore be carried out extremely cost-effectively and quickly. The basic development and execution of such condensers were described, for example, in Oplatka G., Lang H., “Theory and Design of Church Window condensers for large steam turbines” Brown Boveri Rev. 60, 1973, but also in patent specification DE 1 948 073. One characteristic of such church window bundles is the closed slender tube arrangement and the arrangement of a two-stage air cooler, the latter usually being arranged level with the “waistline” of the condenser, hence slightly below its geometric center, in so far as the tube bundle is arranged with its greatest extent in the vertical direction, that is to say so as to stand upright.

[0008] A disadvantage of the previous tube arrangements, however, has proved to be that the number of tubes is restricted to about 5400 tubes per bundle. If this number is exceeded in an arrangement, an excessive blockage of the steam paths occurs due to the condensate raining down. This so-called bundle inundation has serious adverse consequences for the condensation process within the bundles. On the one hand, the steam-side pressure loss rises considerably. Furthermore, because of reduced steam penetration, an increased accumulation of air in the bundle occurs. Moreover, due to the thickening of the condensate film on the outside of the tubes, the heat transmission resistance between the steam and the cooling fluid is increased considerably. This results in a power loss of the condenser in terms of the parameters relating to condenser vacuum, oxygen content and condensate subcooling. In addition, the risk of NH3 corrosion in the case of Cu alloys increases.

[0009] However, bundle sizes of more than 5400 tubes per bundle often occur, for example within the framework of condenser retrofits, in which the jacket geometry and water chamber geometry of the condenser are largely predetermined accordingly.

[0010] The object of the invention is, therefore, to provide a condenser made up from one or more bundles in a modular manner, preferably a condenser designed according to the church window concept, in which the number of tubes in a bundle is to be capable of exceeding the previous limit of about 5400 tubes without a serious loss of power.

[0011] For this purpose, according to the invention, at least one bundle of the condenser has arranged in it a condensate discharge plane which preferably forms approximately a right angle with the isobars of the fluid flow flowing around the tubes. The condenser comprises one or more bundles, each bundle, in turn, comprising a multiplicity of tubes arranged parallel to one another and preferably being designed according to the church window principle. In this case, the tubes may be arranged preferably horizontally, but also vertically or so as to be inclined at an angle. During operation, the tubes have a first fluid flowing through them and a vaporous fluid flowing around them, the first fluid used as cooling fluid having, as a rule, a lower temperature than the vaporous fluid. As a result of heat transmission between the first fluid and the vaporous fluid, the steam condenses when it passes through the bundle. At the same time, the condensate precipitates preferably on the tubes and drips or runs downward as a result of the action of gravity. In the preferred embodiment of the condenser with horizontally arranged tubes, this means that the condensate drips from upper tubes onto tubes located below them. Where a hitherto conventional bundle is concerned, therefore, in so far as the bundles have a large number of tubes arranged one above the other, it may happen that the lower tubes are covered completely or virtually completely by a fluid film of the condensate raining down. The condensate discharge element arranged between the upper sector and the lower sector collects condensate dripping down from the upper sector and discharges this condensate along the condensate discharge element. The tubes arranged in the lower sector below the condensate discharge element thus undergo a markedly reduced condensate load, with the result that the power losses of the condenser are reduced considerably.

[0012] Preferably, the condensate discharge element is arranged in the bundle in such a way that it forms an approximately right angle with the isobaric lines (when condensate discharge elements are not present) of the steam flow flowing around the tubes. This ensures that the pressure profile imparted to the condensate by the steam flow along the condensate discharge element does not have any discontinuities. If, at the same time, the condensate discharge element is arranged in such a way that the condensate flows off in the direction of the pressure gradient, this additionally assists in transporting the condensate away by means of the imparted pressure gradient.

[0013] In a preferred embodiment of the invention, the condensate discharge element is designed as a condensate discharge plane, particularly preferably as a condensate discharge plate. Furthermore, in the case of horizontally or approximately horizontally arranged tubes of the bundle, it is expedient to fasten the condensate discharge plane in each case to support plates of the bundle. At the same time, the condensate discharge plane advantageously extends in each case over the entire region between two support plates in each case. The support plates, usually designed as perforated plates, serve for supporting the tubes of a bundle. As a rule, a plurality of support plates are arranged in a bundle in each case at a particular distance from one another along the tubes. By virtue of the arrangement of a condensate discharge plane which extends over the entire region between two support plates in each case, an upper sector of the tube bundle is delimited completely in this region or in these regions by a lower sector of the tube bundle and the condensate is thus prevented from raining through from the upper sector into the lower sector.

[0014] In the case of a layered arrangement of the tubes of a bundle in rows offset to one another, the rows being offset in each case by one offset step, it is expedient to arrange the condensate discharge plane in the bundle in an arrangement matched to this offset, that is to say at an offset angle corresponding to the offset step. The condensate discharge plane thus runs parallel to an offset line and can consequently be integrated into the bundle, without disturbing the offset arrangement of the tubes. A nonuniform distribution of the tubes as a result of a disturbed offset arrangement can thus be avoided. Such a nonuniform distribution of the tubes would lead adversely to a nonuniform steam flow (bypass problem) through the tubes and ultimately to an increased pressure loss of the steam flow. There is also no need for a comprehensive redesign and regrouping of the tubes if the invention is implemented in accordance with the expedient arrangement for integrating a condensate discharge plane into an already designed tube arrangement or an existing bundle concept. The rows are often arranged in each case so as to be offset to one another by an offset step corresponding to half the distance between the tube center axes of two adjacent tubes of a row.

[0015] In many patterns of arrangement of the tubes, it may be that none of the offset lines runs approximately perpendicularly to the isobaric lines of the steam flow flowing around the tubes. In this case, the offset line which best achieves the approximately perpendicular run is preferably employed.

[0016] The condensate discharge plane arranged according to the invention in the bundle has a first surface and a second surface opposite the first surface. In this case, the first surface points upward, that is to say condensate dripping down from the upper sector accumulates on the first surface. Advantageously, the condensate discharge plane is arranged in the bundle in such a way that the distance between the first surface and the tubes facing the first surface is greater than the distance between the second surface and the tubes facing the second surface. The ratio of the distances is, in this case, preferably two to one. This ensures that there is a sufficiently large distance between the first surface and the tubes facing the first surface to ensure an undisturbed outflow of the condensate along the condensate discharge plane.

[0017] It is advantageous, as a rule, to arrange the condensate discharge element in such a way that the condensate is guided out of the interior of the bundle onto the outside of the bundle and from here flows via a so-called main channel of the condenser into a condensate collecting box. The free condenser space next to the tube bundle is designated as the main channel. In some cases, however, it is also expedient, particularly when a void is arranged in the bundle and this void is connected to a main channel or to the condensate collecting box, to supply the condensate to this void by means of the condensate discharge element.

[0018] In a further preferred embodiment of the invention, a condensate discharge element designed as a condensate discharge duct is arranged in the bundle for the purpose of reducing the condensate load on a lower sector of the bundle. The condensate discharge duct has at least one condensate inlet orifice and at least one condensate outlet orifice. Preferably, the condensate discharge duct is arranged in the bundle in such a way that condensate which forms inside the bundle is guided out of the bundle by means of the condensate discharge duct. For this purpose, the condensate enters the condensate discharge duct through the condensate inlet orifice and is guided in the condensate discharge duct to the condensate outlet orifice. Finally, the condensate passes through the condensate outlet orifice preferably into one of the main channels of the condenser. It is also possible, however, first to supply condensate to a void arranged in the bundle and to lead it from there further on into one of the main channels or into a condensate collecting box. It is thus possible, by means of a condensate discharge duct, for condensate which accumulates at the condensate inlet orifice within the bundle to be discharged outward in a controlled way. The condensate raining from above into the sector below the condensate discharge duct is thus reduced by the amount of the discharged fraction. Preferably, the condensate outlet orifice is provided with a tube extension, so that the condensate is discharged outward in the form of a jet and is prevented from dripping into or being injected into the tube bundle located underneath.

[0019] Preferably, an air cooler box which is arranged above an air cooler of the condenser is designed as a condensate discharge duct. The task of an air cooler in a condenser is to cool further the gas/steam mixture which is not yet condensed after passage through the multiplicity of tubes of the bundle, in order thereby to achieve as complete condensation of the steam as possible. The remaining noncondensable gas, which has, for example, entered the steam circuit via seal leakages in the case of a closed steam turbine process, is subsequently vented out of the water circuit of the steam turbine process by means of a venting system. Since it is necessary, in any case, to separate the remaining tubes of the bundle from the air cooler, the installation of an air cooler box on the air cooler can be implemented in a simple way in terms of construction, even in the case of already designed condensers, without the arrangement of the tubes of the bundle being disturbed as a result. Conventionally, in order to separate the remaining tubes from the air cooler, a separating plate is provided on said air cooler, so that the gas/steam mixture can flow into the air cooler solely through special orifices. By means of an air cooler box arranged according to the invention, the raining of condensate down into the sector below the air cooler box is reduced considerably, with the result that the effectiveness of the condenser is increased.

[0020] The invention is explained in more detail below with reference to exemplary embodiments in conjunction with the drawings, in which:

[0021] FIG. 1a shows the inflow of steam to a condenser bundle which is designed according to the church window concept;

[0022] FIG. 1b shows the isobaric profile in a condenser bundle according to the church window concept;

[0023] FIG. 1c shows a diagrammatic illustration of a condenser made up from a plurality of individual bundles;

[0024] FIG. 2 shows a condenser bundle with condensate discharge planes arranged according to the invention;

[0025] FIG. 3 shows an enlarged detail of the condenser bundle from FIG. 2;

[0026] FIG. 4 shows a detail of a condenser bundle with condensate discharge ducts arranged according to the invention;

[0027] FIG. 5 shows an arrangement of two condenser bundles designed according to the invention, in each case with two-sided drainage orifices of the condensate discharge ducts;

[0028] FIG. 6 shows a further arrangement of two condenser bundles designed according to the invention, in each case with one-sided drainage orifices of the condensate discharge ducts.

[0029] Only the elements essential for understanding the invention are shown. Identically acting or similar components are given the same reference symbols in the various illustrations.

[0030] FIG. 1a illustrates a front view of a condenser bundle 10 which is known from the prior art and has been designed on the church window principle. The characteristic of a bundle designed on the church window principle is a slender tube arrangement with a height of the bundle about four times its maximum width. The bundle 10 illustrated in FIG. 1a comprises a multiplicity of horizontally arranged tubes which in each case run parallel to one another. The tubes are at the same time in each case arranged next to one another and one above the other in rows offset to one another. As a result of the offset arrangement of the tubes, the steam to be condensed, when passing through the bundle, in each case has to avoid the tubes of the next row. This results in a largely uniform distribution of the steam flow in the bundle. FIG. 1a does not illustrate the individual tubes, but merely the arrangement diagram for the sake of clarity. The intersection points of the arrangement lines reproduce the positions of the tubes. The arrangement diagram in the form of a matrix structure is, as a rule, predetermined by support plates which are produced in a simple way as perforated plates with a number of orifices corresponding to the number of tubes and are in each case arranged at particular distances from one another along the longitudinal extent of the bundle. The tubes are in each case inserted through the orifices made in the support plates and are supported by the support plates. The arrangement of the support plates is not illustrated in FIG. 1a.

[0031] The two-stage air cooler 20 illustrated in FIG. 1a represents a further typical characteristic of a church window bundle. The air cooler is arranged approximately level with the waistline of the bundle 10, that is to say slightly below the geometric center of the bundle 10, and subdivides the bundle into a lower part region 14 and an upper part region 16. The air cooler 20 illustrated in FIG. 1a is designed mirror-symmetrically with respect to the center plane of the bundle. It would also be possible, here, to speak of two air coolers arranged mirror-symmetrically to one another. Since the tubes of the bundle illustrated in FIG. 1a have likewise been arranged mirror-symmetrically with respect to the center plane 30 of the bundle, the bundle can thus be subdivided into a left half 32 and a right half 34 mirror-symmetrical to the latter. In the version illustrated here, both halves of the air cooler 20 each have a two-stage makeup, and in each case they comprise a first region 22, in which the gas/steam mixture entering the air cooler is cooled further, and a second region 24, in which the noncondensable gas is collected and finally vented. The venting device is not illustrated in FIG. 1a. The regions of the air cooler are separated from the remaining tubes of the bundle by means of an air cooler casing or by means of separating plates, in order to prevent steam from flowing directly into the air cooler. Steam can flow into the air cooler 20 solely via orifices in the air cooler casing which are made toward the void 40 arranged in the middle of the bundle. The void 40 arranged in the middle of the bundle symmetrically to the center plane of the bundle extends over about half the height of the bundle 10. This free void 40, which is not equipped with tubes and which is also designated as a steam channel, often serves, in a bundle designed on the church window principle, to ensure an approximately equal pressure loss of the steam flow, irrespective of the inflow into the bundle. Thus, along its flow path as far as the air cooler, the steam has to overcome a hydraulic resistance, that is to say flow resistance, which is approximately the same everywhere, irrespective of where it flows into the bundle. This ensures that steam does not flow into the bundle preferentially via a flow path, but in a uniformly distributed manner.

[0032] The bundle 10 illustrated in FIG. 1a is charged from above with steam which comes, for example, from a steam turbine. The steam is distributed to all sides of the bundle 10 according to the flow vectors 50 depicted by way of example in FIG. 1a and also penetrates into the bundle 10 from all sides. An optimum flow through the bundle is thereby achieved, in which the distribution of the steam to the tubes takes place largely uniformly. Regions of the bundle through which the flow passes inadequately or not at all can thus be avoided.

[0033] Regions of the bundle through which the flow passes inadequately would lead locally to intensified and undesirable subcooling of the condensate and also to a likewise undesirable accumulation of noncondensable gases. Consequently, due to the flow passing through the bundle from all sides, optimum efficiency of the condenser is achieved, at the same time with a minimal construction volume of the bundle.

[0034] A further characteristic of a condenser made up from church window bundles is that, as a result of the flow entering the bundle from all sides and as a result of the air cooler being arranged level with the waistline of the condenser, negative subcooling of the condensate occurs, that is to say the temperature of the condensate is higher than the saturation temperature corresponding to the pressure at condenser level. The physical cause of this is the different flow velocities of the steam on the bottom side of the bundle, as compared with the flow velocities of the steam on the top side of the bundle, along with the pressure difference of the steam caused thereby on the bottom side of the bundle, as compared with the top side of the bundle. Negative subcooling of the condensate is usually desirable.

[0035] The steam flowing into the bundle condenses as a result of heat being extracted by the cooling fluid flowing in the tubes and is precipitated on the tubes. Water is also usually used as cooling fluid. As a result of the action of gravity, the precipitated condensate first runs downward on the respective tubes, accumulates there and subsequently drops onto the tubes in each case arranged underneath. There is therefore a greater occurrence of condensate in the lower regions of a bundle, with the result that the heat transmission between the tube and the steam flow is also impaired.

[0036] In FIG. 1b, isobars of the steam flow are depicted in the bundle designed according to FIG. 1a. The concentric arrangement of the unimodal pressure depression lines about the bundle axis upstream of the air cooler 20 can be seen clearly. As a result of the acceleration of the steam flow, an additional drop in the pressure of the steam flow toward the air cooler occurs in the steam channel 40.

[0037] FIG. 1c shows a diagrammatic illustration of the makeup of a condenser, in which six bundles 10a-10f designed on the church window principle are arranged. The bundles are charged with steam from above. The condensate collects in a condensate collecting box 42 arranged below the condenser. The bundles are arranged in such a way that sufficient space remains in each case between the bundles to ensure an undisturbed flow of the steam around the individual bundles. The space between two bundles in each case is designated as a steam main channel 44. The modular makeup of the condenser can be seen clearly in FIG. 1c, since, without any higher outlay in terms of design, the condenser could be extended by further bundles or else reduced. It is therefore easily possible to match the condenser to special requirements, such as, for example, a necessary power output.

[0038] FIG. 2 illustrates a condenser bundle 10 which is executed according to the invention and has been designed on the church window principle. Condensate discharge elements are arranged according to the invention in the condenser bundle. The bundle illustrated here has a height of about 6 m and a width of about 1.5 m. The condensate discharge elements are designed as condensate discharge planes 60a-60d, in the bundle illustrated here two condensate discharge planes 60a, 60b being arranged in the lower part region 14 of the bundle and two further condensate discharge planes 60c, 60d being arranged in the upper part region 16 of the bundle. The part regions of the bundle are delimited from one another, here, by a horizontally running void 46 and the air cooler 20 arranged below the void. The invention can be implemented both with single-stage and with two-stage air coolers.

[0039] At the same time, the condensate discharge planes 60a-60d, which are designed in a simple way essentially as a planar plate, are arranged in the bundle in such a way that they in each case form an approximately right angle with the isobars of the steam flow. The result of this is that the condensate outflow along the condensate discharge planes is neither accelerated nor slowed down excessively by the pressure profile of the steam flow.

[0040] The condensate discharge planes are expediently fastened in each case to two support plates of the bundle. The support plates are not illustrated in FIG. 2. The bundle 10 illustrated in FIG. 2 comprises, in addition to a multiplicity of tubes (the tubes reproduced by means of filled-up circles in FIG. 2 constituting support tubes of the bundle and the tubes arranged in the edge region of the bundle each being designed with double the wall thickness), a (single-stage or two-stage) air cooler 20 which is designed symmetrically to the center plane of the bundle and is arranged approximately level with the waistline of the bundle. Each of the symmetrically designed wings of the air cooler 20 comprises, on the one hand, a tube-equipped region 22 and, furthermore, a venting device 24. The regions of the air cooler are separated from the remaining tube-equipped sectors of the bundle by means of an air cooler casing or by means of separating plates. The steam or the gas/steam mixture not yet condensed until then during passage through the tube-equipped part of the bundle enters the tube-equipped region 22 of the air cooler solely via the steam channel 40, which is arranged in the middle of the bundle and extends over a substantial part of the height of the bundle, and via orifices made in the air cooler casing toward the steam channel. The gas/steam mixture is cooled once again in the tube-equipped region 22 of the air cooler, the steam being condensed out essentially completely and only noncondensable gases remaining. The noncondensable gases are vented through orifices in the venting box by means of vacuum pumps.

[0041] In order to avoid a complicated reorganisation or regrouping of the tubes as a result of the insertion of the condensate discharge planes 60a-60d, the condensate discharge planes 60a-60d have in each case been arranged in the bundle 10 so as to match the offset arrangement of the tubes. The tubes of the bundle illustrated in FIG. 2 are in each case arranged in rows layered one above the other, each row being arranged so as to be offset by one offset step to the row lying below it and also to the row arranged above it. The offset corresponds, here, in each case to half the distance between the tube center axes of two tubes arranged next to one another in a row.

[0042] The distances of the top sides of the condensate discharge planes 60a-60d from the tubes facing the top sides are selected larger than the distances of the bottom sides of the condensate discharge planes from the tubes facing the bottom sides. Preferably, the condensate discharge planes are arranged in such a way that the distance between the top sides and the respective tubes is twice as large as the distance between the bottom sides and the respective tubes. The condensate accumulates on the top sides of the condensate discharge planes and subsequently runs off along the condensate discharge planes. The larger distance selected between the top sides and the tubes ensures that sufficient space remains to make sure of an undisturbed outflow of the condensate. By contrast, no condensate accumulates on the bottom sides, so that a smaller distance is sufficient.

[0043] The condensate in each case dripping down from above accumulates on the top sides of the condensate discharge planes 60a-60d and, by virtue of the action of gravity, flows off from here along the condensate discharge planes 60a-60d, as identified in FIG. 2 as the flow vector 54. It is thus possible for the condensate raining down in a part region of the bundle to be discharged in a controlled manner either, for example, into the steam main channels or into the steam channel arranged centrally in the bundle. In this case, the steam channel expediently has a condensate outflow, via which the condensate supplied to the steam channel is led further on either into the steam main channel or directly into the condensate collecting box. The region located in each case below the condensate discharge plane is thus relieved of the condensate discharged by the condensate discharge planes and coming in each case from the upper region of the bundle, so that a reduction in efficiency due to bundle inundation is avoided in the region below the condensate discharge plane.

[0044] Furthermore, the condensate discharge planes 60a-60d illustrated in FIG. 2 have in each case at their lower ends collecting grooves 62a-62d, with the aid of which the condensate running off along the condensate discharge planes is first collected and guided to a longitudinal position of the bundle, in order to be discharged bunched together into the steam main channel of the steam channel here. For this purpose, the collecting grooves preferably have orifices at their ends.

[0045] While, according to the illustration in FIG. 2, the condensate discharge planes 60c, 60d arranged in the upper part region 16 of the bundle symmetrically to the center axis of the bundle, guide the collected condensate in each case into the steam channel 40 provided in the middle of the bundle, the condensate is guided into the steam main channels by the condensate discharge planes 60a, 60b arranged in the lower part region 14 and likewise designed symmetrically to the bundle center axis. Such an arrangement of the condensate discharge planes 60a-60d is expedient in as much as the condensate, after flowing out of the collecting grooves, thus in both cases has to cover a falling distance which is only relatively short in each case. This largely avoids the condensate splashing back as a result of impingement on, for example, the condenser bottom.

[0046] FIG. 3 illustrates, enlarged, a detail A from FIG. 2 in order to make clear the arrangement of the tubes. The tubes 12a-12d are in each case positioned at the corners of a parallelogram. The tubes 12a-12d illustrated in the detail A come from three different arrangement rows, the rows in each case being arranged so as to be offset to one another by an offset step corresponding to half the distance between the tube center axes of two adjacent tubes.

[0047] FIG. 4 shows a further bundle 10 designed according to the invention, only a detail of the bundle being illustrated. The detail reproduces an upper tube-equipped part region 16 of the bundle and a lower tube-equipped part region 14 of the bundle, a (single-stage or two-stage) air cooler 20 designed symmetrically to the center plane of the bundle and a steam channel 40 which is arranged in the middle of the bundle and through which the not yet condensed gas/steam mixture flows into the air cooler 20. The mirror-symmetrically designed air cooler 20 is made up in a similar way to the air cooler illustrated in FIG. 2, each wing of the air cooler comprising a tube-equipped region 22 and a venting device 24 which is arranged on the outsides and which is connected in each case to a venting duct and to one or more vacuum pumps not illustrated in FIG. 4. The tubes of the tube-equipped regions are illustrated in cross section in each case only at the boundaries of the regions. The remaining tubes, which are located within the tube-equipped regions, are reproduced in FIG. 4 merely diagrammatically by the arrangement matrix.

[0048] According to the invention, the air cooler boxes 80a, 80b above the air coolers 20a, 20b are in each case produced as condensate discharge ducts, the top sides 82a, 82b of the air cooler boxes at the same time also functioning as condensate discharge planes. The air cooler boxes 80a, 80b each have a rectangular, internally hollow cross section and extend both in width and in length over the entire region of the air coolers. Condensate dripping down or raining down from above first accumulates on the top side 82a, 82b of the air cooler boxes. In order to prevent the condensate from flowing off from the top side both into the steam main channels and into the steam channel 40, in each case two limiting fins 84a-84d are additionally mounted on the top side of the air cooler boxes and thus delimit the condensate collecting plane relative to the outside. The air cooler boxes are expediently fastened in the longitudinal direction to the support plates of the bundle, so that the condensate collecting planes are delimited in the longitudinal direction by the support plates. A further, small limiting fin 86a, 86b is arranged in each case directly in front of the condensate inlet orifices 88a, 88b of the air cooler boxes 80a, 80b. When the level of the condensate which has accumulated on the top side of an air cooler box exceeds the height of the small limiting fin 86a, 86b, condensate flows through the condensate inlet orifice 88a, 88b into the respective air cooler box 80a, 80b. Furthermore, each of the air cooler boxes 80a, 80b has a condensate outlet orifice 90a, 90b, via which the condensate which has entered the air cooler box can flow out of the air cooler box again. The condensate outlet orifice is preferably designed as a tubular piece. The condensate can thus be discharged outward in the form of a jet. This prevents the condensate or a drop of condensate from splashing back into the tube arrangement lying below it.

[0049] Moreover, the two air cooler boxes 80a, 80b illustrated in FIG. 4 are connected to one another across the steam channel 40 by means of a tubular element 92. Condensate flowing out of the air cooler box 80a located on the right in FIG. 4 thus passes into the left air cooler box 80b via the tubular element 92. Such an arrangement of the tubular element is expedient particularly when the condensate is to flow out of the air cooler box on only one side of the bundle. In the execution of the invention according to FIG. 4, the condensate which has accumulated in the two air cooler boxes flows into the left steam main channel solely via the condensate outlet orifice 90b of the left air cooler box 80b, while no condensate outflow takes place on the other side. The tubular elements preferably have a small diameter, so as not to block the steam coming from above.

[0050] An outflow on only one side may be expedient, for example, when two bundles are arranged at only a short distance from one another. In order to prevent outflowing condensate from re-entering the other bundle in each case, the condensate outflow takes place only on that side of the bundle which in each case faces away from the adjacent bundle, as illustrated by way of example in FIG. 6. By contrast, FIG. 5 illustrates an arrangement of two bundles 10, 10′, each with a two-sided outflow.

[0051] The bundles 10, 10′ illustrated in FIGS. 5 and 6 also have, in addition to the air cooler boxes 80a, 80b, 80a′, 80b′ designed according to the invention, in each case four condensate discharge planes 60a-60d, 60a′-60d′ arranged according to the invention.

[0052] With the aid of the bundles designed according to the invention, the condensate load in the lower regions of a bundle can be reduced considerably. As a result, the bundles can be made larger, that is to say with a much larger number of tubes, as compared with the bundles capable of being produced hitherto, without an appreciable impairment in condenser efficiency occurring as a result of bundle inundation. The bundles designed according to the invention thus allow a considerable expansion of the range of use of condensers having a modular makeup, in particular condensers designed on the church window principle.

LIST OF REFERENCE SYMBOLS

[0053] 2 Condenser

[0054] 10,10′,

[0055] 10a-10f (Condenser) bundle

[0056] 12 Position of a tube

[0057] 14 Lower part region of the bundle

[0058] 16 Upper part region of the bundle

[0059] 20 Air cooler

[0060] 20a,20b Wing of the air cooler

[0061] 22 Tube-equipped region of the air cooler

[0062] 24 Venting device of the air cooler

[0063] 26 Air cooler casing

[0064] 30 Center plane of the bundle

[0065] 32 Left half of the bundle

[0066] 34 Right half of the bundle

[0067] 40 Void/steam channel

[0068] 42 Condensate collecting box

[0069] 44 Steam main channel

[0070] 46 Horizontal void

[0071] 50 Flow vector of the steam flow

[0072] 52 Isobars

[0073] 54 Flow vector of the condensate

[0074] 60,60a-60d,

[0075] 60a′-60d′ Condensate discharge plane

[0076] 62a-62d Collecting grooves

[0077] 70 Support tube

[0078] 80a,80b,

[0079] 80a′,80b′ Air cooler box

[0080] 82a, 82b′ Top side of the air cooler box

[0081] 84a-84d Limiting fin

[0082] 86a, 86b Small limiting fin

[0083] 88a, 88b Inlet orifice

[0084] 90a, 90b Outlet orifice

[0085] 92 Intermediate element

[0086] d Distance between two tube center axes

Claims

1. A condenser (2) for condensing a vaporous fluid, with at least one bundle (10), the bundle comprising a multiplicity of tubes (12) arranged parallel to one another, the tubes (12) having a first fluid flowing through them and the vaporous fluid flowing around them, characterized in that a condensate discharge element (60, 80) is arranged in the bundle (10), the condensate discharge element forming approximately a right angle with the isobars (52) of the fluid flow flowing around the tubes.

2. The condenser as claimed in

claim 1, the condensate discharge element being a condensate discharge plane, preferably a condensate discharge plate.

3. The condenser as claimed in one of the preceding claims, the tubes (12) being arranged in rows, and the rows being arranged in a layered arrangement one above the other in each case so as to be offset to one another by one offset step, the offset step being preferably equal to half the distance (d) between two tube center axes, and the condensate discharge plane (60) being arranged in the bundle approximately at an offset angle corresponding to the offset step.

4. The condenser as claimed in one of the preceding claims, the condensate discharge plane (60) arranged in the bundle having a first surface (66) facing the tubes and a second surface (64) opposite the first surface (66), the condensate accumulating on the first surface (66), and the condensate discharge plane (60) being arranged in the bundle (10) in such a way that the distance between the first surface (66) and the tubes facing the first surface is larger than the distance between the second surface (64) and the tubes facing the second surface, preferably in a ratio of two to one.

5. The condenser as claimed in one of

claims 2 to

4, a collecting groove (62a-62d) being arranged at a lower end of the condensate discharge plane (60).

6. The condenser as claimed in one of

claims 2 to

5, the bundle (10) having arranged in it a void (40) which is connected to a region outside the bundle by means of an outflow for the outflow of condensate, and the condensate discharge plane (60) being arranged in such a way that the condensate is led into this void (40) by means of the condensate discharge plane (60).

7. The condenser as claimed in one of

claims 2 to

6, the condensate discharge plane (60) being arranged in such a way that the condensate is led out of the interior of the bundle onto the outside of the bundle.

8. The condenser as claimed in one of the preceding claims, the void (40) being arranged in the middle of the bundle (10), and two condensate discharge planes (60c, 60d), which extend in each case from an outer side of the bundle to the void (40) and lead the condensate into the void (40), being arranged in an upper region (16) of the bundle in an arrangement symmetrical to the center plane (30) of the bundle, and two further condensate discharge planes (60a, 60b), which extend in each case from the void (40) of the bundle to an outer side of the bundle and lead the condensate onto the respective outer side of the bundle, being arranged in a lower region (14) of the bundle in an arrangement likewise symmetrical to the center plane (30) of the bundle.

9. The condenser as claimed in one of the preceding claims, a condensate discharge duct (80a, 80b) being arranged as a condensate discharge element in the bundle (10), and the condensate discharge duct (80a, 80b) having at least one condensate inlet orifice (88a, 88b) and at least one condensate outlet orifice (90a, 90b).

10. The condenser as claimed in

claim 9, an air cooler (20) being arranged in the bundle (10), preferably level with the waistline of the bundle, and the condensate discharge duct (80a, 80b) being arranged on the air cooler (20).

11. The condenser as claimed in one of claims 9 or 10, the condensate discharge duct (80a, 80b) extending from an outer side of the bundle to a void (40) arranged in the bundle.

12. The condenser as claimed in

claim 11, the void (40) being arranged in the middle of the bundle, and two condensate discharge ducts (88a, 88b) extending in each case from an outer side of the bundle to the void (40) in an arrangement symmetrical to the center plane (30) of the bundle.

13. The condenser as claimed in

claim 12, the condensate discharge ducts (88a, 88b) being connected to one another by means of an intermediate element (92) which extends over the region of the void (40).

14. The condenser as claimed in one of

claims 9 to

13, the top side (82a, 82b) of the condensate discharge duct (80a, 80b) being designed as a condensate discharge plane.

15. The condenser as claimed in one of the preceding claims, the bundle (10) being a bundle designed on the church window principle.

16. The condenser as claimed in one of the preceding claims, the bundle (10) having a height about four times its maximum width, and preferably a two-part air cooler (20) being arranged in the bundle (10), preferably in a symmetrical arrangement, level with the waistline of the bundle.

17. The condenser as claimed in one of the preceding claims, steam flowing into the bundle (10) from all sides, and the steam which flows into the bundle from all sides having to overcome approximately the same flow resistance between the outside of the bundle and the air cooler.