EP0265725B1 - Heat exchanger - Google Patents

Description

The invention relates to a heat exchanger according to the preamble of patent claim 1.

According to the prior art (DE-A 2 907 810), heat exchangers are manufactured with central collecting containers or tubes in such a way that the lancet-shaped matrix profile tubes are inserted into a wall in the opening of the collecting container or tube and then connected cohesively, for example by soldering are so that a fluidic passage from the collecting container to the interior of the profile tubes is created. oie through openings in the collecting container wall can be formed by drilling or eroding before threading the profile tubes, which is a complex perforation procedure. The individual assembly of the profile tubes, in particular the threading, is comparatively cumbersome, and this is because there is a tight play (movable fit) between the profile tube and the through opening in the wall. Tight tolerances of the hole and profile tube must be observed with regard to perfect soldering or another connection.

In the endeavor to achieve a relatively simple, problem-free and quick assembly of the matrix profile tube on the header or distributor tube, a heat exchanger concept known from DE-A 3 242 842 provides that blocks are attached to the matrix profile tubes in the area of at least one profile tube end, which end the profile tube end enclose that the matrix profile tubes are arranged close together in the area of their blocks, so that the blocks form a wall of the collecting container or pipe, and that the connection points of the blocks are sealed fluid-tight.

In particular, in this known case, the blocks are to be applied to the profile tube ends by metal sintering, powdered sintered material being arranged in a shape approximating the desired contour of the block around the respective connection-side profile tube end and sintered gas-tight. In addition, the outer contact surfaces of the blocks can be machined with dimensional accuracy before the matrix profile tubes are arranged. Cold forging, embossing or profile grinding can also be considered as machining processes.

Furthermore, in the present known case, the profile tube base geometries can be essentially rhombic or hexagonal or honeycomb-shaped.

The present known case enforces a comparatively complicated and high-precision profile tube foot production. Furthermore, the entire matrix connection area (heat exchanger base) must also be assembled in a relatively complicated manner from a relatively large number of blocks which are extremely precisely matched to one another. Such a type of heat exchanger base or container structure assembled from very small particles has disadvantages with regard to the required container or base structure strength.

In another heat exchanger concept known from DE-A 3 310 061, the matrix profile tubes, with their ends containing an elongated oval profile cross section, are to be firmly integrated in a fluid-tight manner between, if appropriate, annular container wall elements joined in layers; in other words, the wall elements in the region of their mutual joining surfaces each have semi-elliptically pre-shaped mutual cutouts for the elongated oval ends of the matrix profile tube. This known concept also requires extremely precise machining of the wall elements in question; Despite the most precise machining, there is practically no bridging of differences in shape and manufacturing tolerance, particularly in the areas of the front and rear profile ends on the connection side; locally different profile tube crushes can result, e.g. When joining wall elements and profile tubes in layers, which in turn can affect the material connection, for example by soldering, between profile tube ends and wall elements (local solder displacements, no solid homogeneous soldering). Also, in the known case, impairment of notch effects with regard to the profiled tubes sitting in the wall elements with relatively slim pointed ends cannot be ruled out.

Furthermore, in the known case, matrix profile tube fields and thus correspondingly assigned fields of the oval or elliptical recesses are formed between the wall elements: this in the sense that the matrix profile tubes in question essentially spatially at uniform mutual distances within the framework of an optimal hot gas flow and while ensuring the necessary hot gas blocking interlocking.

If this condition is fulfilled (optimally flowed by the hot gas compact matrix), the elongated oval profile cross-sections and thus the associated openings in the header pipe or heat exchanger bottom, successively in the direction of the layer, lead to a weakening of the strength of the header or distributor pipe in the matrix connection area; this also applies analogously to the heat exchanger concept already mentioned at the beginning, known from DE-A 2 907 810.

From US-A 3 627 039 a heat exchanger operating according to the countercurrent principle is known, in which the outer ends of tubes of a heat exchanger matrix arranged in parallel next to one another are arranged in a uniformly rectangular, flattened form, and immediately following one another, between adjacent profile strips; Such a combination of strips and flattened tube ends of the matrix is intended to form the local floor structure at a correspondingly adapted frame-like opening in the heat exchanger housing. In the known case, the pipe end assembly is pieced together locally and is unstable in strength (soft) without an operationally stable individual to ensure pipe bracket. Instructions for achieving a comparatively large number of profile tubes that can be accommodated per floor volume (large matrix volume) and at the same time operationally stable and fluid-tight individual tube anchoring on collecting or distribution tubes composed of elements cannot be found in the known case.

The invention has for its object to provide a heat exchanger according to the preamble of claim 1, in which a collector or manifold base can be created with relatively little effort, which creates perfect conditions for a fluid-tightly fixed matrix profile connection with optimal strength.

The object is achieved with the features of the characterizing part of claim 1 according to the invention.

The respective profile tubes of the matrix can be shaped into a square or rectangular shape on the foot side before insertion or insertion into the relevant floor structure of a distributor or collector tube; this can e.g. done rationally on rotary hammers, whereby inner mandrels can be used depending on the degree of forming. As a result of the rectangular or square shape of the profile tube foot ends, the components can be "interlocked" with one another during assembly and fixed in a predetermined position; Rectangular or square openings, also referred to as “pockets”, can be provided between the wall elements forming the relevant collecting pipe or distributor pipe or the heat exchanger base in order to integrate the relevant foot ends of the profiled pipes therein positively and firmly. As a result of the straight, smooth side walls of the foot ends - that is, straight, smooth walls following the relevant course of the layer - "pockets" which are open on one side can be covered in a slightly form-fitting, flush manner by strip-shaped connecting elements which also run in a straight line.

In the present heat exchanger, essential design advantages with regard to a so-called "modular" construction concept can also be used, in that it is comparatively simple to create preassembled individual assemblies (elements, connecting elements, foot ends and profile tubes), which are assembled with peer assemblies and preassembled assemblies to form a pipe or floor structure can be.

With regard to advantageous embodiments of the invention, reference is made to claims 2 to 9.

• Fig. 1 die schematische und perspektivische Darstellung eines bekannten und für die Durchführung der Erfindung geeigneten Profilrohrwärmetauschers,
• Fig. 2 einen Teilausschnitt aus einem Matrixprofilrohrfeld,
• Fig. 3 die äußere Ansicht einer Sammel- oder Verteilerrohrbodensektion mit hier zwar schon rechteckigen Fußenden zwischen den schichtweise aneinandergefügten Elementen, hier allerdings noch ohne Vorkehrungen gemäß der Erfindung zwecks erhöhter Bodenfestigkeit bei zugleich vergleichsweise großer Profilrohrabstandsdichte,
• Fig. 4 eine perspektivisch dargestellte obere Matrixprofilrohransicht, in der eine gemäß der Erfindung im wesentlichen konzentrische Fußverdrehung gegenüber dem zugehörigen Profilrohr verdeutlicht ist,
• Fig. 5 die äußere Ansicht einer gemäß der Erfindung ausgebildeten Sammel- oder Verteilerrohrbodensektion in Kombination mit der fußseitig verdrehten Profilrohrkonfiguration nach Fig. 4
• Fig. 6 die äußere Ansicht einer weiteren Sammel-oder Verteilerrohrbodensektion gemäß der Erfindung in Kombination mit der fußseitig verdrehten Profilrohrkonfiguration nach Fig. 4,
• Fig. 7 eine beispielsweise im Hinblick auf Fig. 6 ausgewählte Sammel- oder Verteilerrohrboden-Querschnittssektion gemäß der Erfindung unter Einschluß einer ersten gegenseitigen Elementausbildungsund Befestigungsweise,
• Fig. 8 eine beispielsweise im Hinblick auf Fig. 7 ausgewählte Sammel- oder Verteilerrohrboden-Querschnittssektion gemäß der Erfindung unter Einschluß einer zweiten, die Ausführung nach Fig. 7 weiter ausgestaltenden gegenseitigen Elementausbildungs- und Befestigungsweise,
• Fig. 9 die äußere Ansicht einer weiteren Sammel-oder Verteilerrohrbodensektion gemäß der Erfindung in Kombination mit der fußseitig verdrehten Profilrohrkonfiguration nach Fig. 4 und
• Fig. 10 eine von der Fußinnenseite aus gesehene Ansicht des Profilrohrfußendes in konzentrisch abgewinkelter Verdrehstellung gegenüber dem zugehörigen Profilrohr, hier jedoch - in Abweichung von Fig. 4 - eine schlankere und längere rechteckige Profilrohrfußgeometrie verdeutlichend.

The invention is further explained, for example, with the aid of the drawings; show it:

• 1 is a schematic and perspective view of a known profile tube heat exchanger suitable for carrying out the invention,
• 2 shows a partial section from a matrix profile tube field,
• 3 shows the outer view of a header or manifold tube section with here already rectangular foot ends between the elements joined together in layers, but here without precautions according to the invention for the purpose of increased soil strength with a comparatively large profile tube spacing density,
• 4 is a perspective view of an upper matrix profile tube view, in which an essentially concentric rotation of the foot relative to the associated profile tube is illustrated,
• 5 shows the external view of a header or distributor tube section designed according to the invention in combination with the profile tube configuration according to FIG. 4 rotated on the foot side
• 6 shows the external view of a further collecting or distributor tube bottom section according to the invention in combination with the profile tube configuration according to FIG. 4 twisted on the foot side, FIG.
• 7 is a cross-sectional section of a header or manifold base selected according to the invention, for example with regard to FIG. 6, including a first mutual element formation and fastening method;
• 8 is a cross-sectional section of a header or manifold base selected according to the invention, for example with reference to FIG. 7, including a second mutual element formation and fastening method further developing the embodiment according to FIG. 7,
• 9 shows the external view of a further collecting or distributor tube section according to the invention in combination with the profile tube configuration according to FIGS
• Fig. 10 is a view seen from the inside of the foot of the profile tube foot end in a concentrically angled rotational position relative to the associated profile tube, but here - in deviation from Fig. 4 - clarifying a slimmer and longer rectangular profile tube foot geometry.

The invention is based on a heat exchanger according to FIG. 1, which, as two compressed air ducts arranged essentially parallel to one another, here has two, for example, separate header and distributor pipes 1, 2. According to the darkened contour, the collecting and distribution pipes 1, 2 are closed at the respective rear ends. The profile tube matrix 3 projecting laterally from the two compressed air ducts 1, 2 transversely against the hot gas flow H consists of initially straight, parallel profile tube strands 4, 5 which merge into a common arcuate deflection section 6. In operation, compressed air to be heated is fed into the upper collecting pipe 1 (D 0, then flows through the straight section 4 (D @), whereupon it is deflected via the deflection section 6 (D #) and then flows through the straight section 5 in the opposite direction of flow (D $ ), from which it flows through the lower manifold 2 in the heated state (D _% ) in order to be supplied to a suitable consumer, for example the combustion chamber of a gas turbine engine.

Deviating from Fig. 1, the invention would also be practical in a heat exchanger in which the aforementioned compressed air ducts (collecting and distribution pipe) are not arranged separately, but are integrated in a common collecting and distribution pipe, from which the pipe matrix projects on both sides in a U-shape.

2 initially embodies the conventional arrangement of a profile tube field recorded here in a greatly enlarged manner, for example as a section of the straight-leg profile tube strands 4 according to FIG. 1. For example in FIG. 2, the respective matrix profile tubes of three rows of profile tubes extending in the longitudinal direction of the tube guide - in sequence, from top to bottom - labeled 4 ₁ , 4 ₂ and 4 ₃ . The matrix profile tubes 4 ₁ , 4 ₂ , 4s are arranged at equal distances from one another in the longitudinal and transverse pipe guide directions; out

Fig. 2 can also be seen that the profile tubes, for example 4 ₂ , engage with their hot gas upstream and downstream ends in the end-side spaces left between adjacent other profile tubes, for example 4 ₁ , 4 ₃ . In this way, the highly compact field of matrix tube profiles that is characteristic of heat exchangers in the sense of FIG. 1 is created. The arrangement of the profiled tube array according to FIG. 2 could, for example, also be defined by division planes M inclined at the same inclination angles with respect to the relevant large ellipse axes A of the profiled tubes, which are passed through profile centers designated M1, M2 and M3. With regard to their respective major axes A, the profiled tubes 4 ₁ , 4 ₂ and 4 ₃ in FIG. 2 are set at a right angle R with respect to a central collecting or distribution tube cross plane E, the angle of incidence β of the parting planes M to plane E being determined from the angle difference Ra calculated.

As can also be seen from FIG. 2, the matrix profile tubes 4 ₁ , 4 ₂ and 4 _{3 have} an elliptical or elongated oval, aerodynamically optimized profile cross section, wherein each profile tube has two compressed air, for example D2 (FIG 1) has leading inner channels 8, 9.

3, each profile tube, e.g. 41, be equipped with a right-angled profile symmetrically assigned foot end 10; the profile tube foot end 10 in question, however, still lies with its longitudinal center plane in the plane of the large ellipse axis A (FIG. 2).

With regard to the profile formation and geometry indicated in FIG. 2, FIG. 3 already embodies an advantageous partial aspect of the invention, according to which two elements 11, 12 of the header or distributor pipe 1 or 2 (FIG. 1) forming the matrix connection area (FIG. 1) between the in each case include mutual connecting and joining surfaces 13, 14, which here extend in the center of the profiled tube foot, and which have a rectangular shape adapted to accommodate and enclose the relevant foot end 10.

From FIGS. 3 and 4 it can also be seen that the section of the profile tube, for example 4 ₁ , around which hot gas flows (H - FIG. 1) projects over the associated foot end 10 with the profile end edge on the upstream and downstream sides; Foot end 10 and associated profile tube, for example 4 ₁ , each form a fluidically communicating, self-contained structural unit, the excess length of the profile being illustrated in FIG. 3 by dashed contours. According to FIG. 3, relatively large foot or recess distances along the common joining surfaces 13, 14 must also be maintained, in the case of a profile formation and arrangement in the sense of FIG. 2, and the number of elements used being relatively large.

4 and 5 embody a complete variant of the invention, in which the respective foot end 10 is deformed concentrically twisted at the same inclination angle a with respect to the large ellipse axis A of the elliptical cross section of the associated profile tube, for example 4 ₁ . 4, this torsional deformation can be such that the respective large ellipse axis A or the positionally identical central tube plane intersects the associated foot end 10 diagonally. In FIG. 5, the respective foot ends 10 thus extend longitudinally in the inclined parting planes M, which are already defined in more detail in FIG. 2, while the associated profiled tubes, e.g. relative to the torsional deformation of the foot ends 10 (angle of inclination a, see also FIG. 4) 4 ₁ , with their large axis A at a right angle R (FIG. 2) to the central collector or distributor pipe central plane E. According to FIG. 5, the mutual joining surfaces, for example 17, 18 of the elements 19, 20 also run in the oblique direction Partition planes M. When comparing with FIG. 3, it follows that in FIG. 5 the number of required, possibly annular elements 19, 20 is half as large, so each element 19 or 20 is comparatively firm and stable, which in turn is favorable affects the entire strength structure of the header or manifold bottom, and the number of required joints or mutual joining surfaces decreases to the same extent.

It enables the embodiment according to Fig. 4, a collecting or distribution pipe in different ways in a number in parallel to the division plane M cuts in e.g. to divide annular elements. A further variant of the invention results from this in FIG. 6.

Here, two elements 21, 22 are each formed such that they enclose the rectangular foot ends 10 of the respective profile tubes, for example 4 _1, tightly like pliers along the mutual joining surfaces lying in the inclined parting planes M with the corresponding rectangular recesses; The elements 21, 22 are smooth-walled along the outer joining surfaces, for example 23, 24, which run parallel to the division planes M. Advantageously, two elements 21, 22 can each form independent assembly units which can be equipped with the associated foot ends 10 and the associated profiled tubes, for example 4 ₁ - FIG.

There are additional element divisions in FIG. 6 compared to FIG. 5, but in FIG. 6 there are uninterrupted joining surfaces, for example 23, 24 see what in turn benefits the manufacturing process.

4_@, 4# (Fig. 2) von den Flanken her unter Druck zu setzen und bei gleichzeitiger Wärmezufuhr (z.B. durch eine elektrische Widerstandserhitzung) eine stoffschlüssige Verbindung zu erzeugen.For example with regard to FIG. 6, it would be possible, for example, to have two ring-shaped elements 21, 22 and the foot ends 10 enclosed therein, together with associated profile tubes

To put 4 _@ , 4 # (Fig. 2) from the flanks under pressure and to generate a cohesive connection with the simultaneous supply of heat (eg by electrical resistance heating).

The necessary steps for assigning, merging and joining parts as well as the subsequent quality control can be carried out largely automated; As an intermediate product, an element is created from which the complete heat exchanger base or heat exchanger can be assembled by adding the required number of identical elements, the joints of the completely pre-assembled modules lying on planar surfaces and their edges simple shapes, e.g. Represent circles or ellipses. The integral joining of the elements can be flat, e.g. by soldering or - along the mutual element edges - by laser - or EB welding.

This can include According to FIG. 7, it may be advantageous if lip-like projections 25, 26 of the elements provide the mutual joining surfaces, and preferably in the foot-side region of these elements; Above the lip-like projections 25, 26, upwardly open joints 27 can remain between the elements 21, 22. The welding can then take place along the lip-like projections 25, 26; the projections 25, 26 can be worked off later for possible repair purposes in order to be able to loosen the bandage at this point.

Fig. 8 shows a modification of Fig. 7 in such a way that two adjacent elements 21, 22 are joined together and centered by means of webs 28 which engage under one another on the inside of the manifold or distributor pipe.

A further embodiment of the invention (Fig. 9) is characterized in that an element 29 is formed along both-sided joining surfaces 30, 31 with outwardly open rectangular recesses 32 for the respective foot ends 10 of the profile tubes 41, 42, 43 (Fig. 2) is, each of which an open foot end side is covered by strip-shaped connecting elements 33, 34, along the joining surfaces on both ends, whereby the element 29, the connecting elements 33, 34 and the foot ends 10 together with associated profile tubes can each form an independent assembly unit.

Each assembly unit can then be joined with a relevant assembly unit in a material-homogeneous manner. A suitable soldering, welding or diffusion connection method can be selected for the mutual connection of the respectively pre-assembled assembly units as well as for the individual component connection of each independent assembly unit. The spaces marked Z in Fig. 9 can be replaced by additional material during soldering or e.g. be closed by one-sided sealing welding.

On the basis of an unchanged matrix profile tube shape and size, FIG. 10 differs mainly from FIG. 4 in that the foot end 10 ′ in question is made narrower and longer; otherwise the same geometric aspects and nomenclatures apply as in FIG. 4.

The invention can also be used advantageously in a profile tube matrix through which hot gas flows obliquely; this would e.g. mean that with a substantially concentric angular rotation, a, according to Fig. 10, the foot ends 10 'of the profile tubes, e.g. 4 could in each case be arranged longitudinally in divisional planes (formerly M), which, for example, are positioned at a right angle (formerly β) to the longitudinal or central plane of the collecting pipe or distributor pipe E; the profile tubes, e.g. 4; could then lie with their respective large elliptical axes A in inclined planes, the angle of inclination of which to the central or collecting tube longitudinal center plane E results from the angle of inclination angle a.

Claims (9)

1. A heat exchanger with a tube matrix (3) consisting of spatially nesting inter-engaging profile tubes (4 4_@) with in each case like-sized elliptical cross- section and having compressed air flowing through them while a flow (H) of heated gases flows around them transversely and in the direction of the profile extension determined by the major axis (A) of the ellipse, the said profile tubes being, for supplying compressed air into the matrix (3) or for carrying it out of the matrix (3), connected to at least one compressed air collecting and one distributor tube (1; 2), and which, for tube connection, consist of sandwich-like fluid-tightly adjacently disposed elements (19, 20; 29, 34) between which the profile tubes (4 4_@) are fluid-tightly and positively bonded at their ends, characterised in that

- the elements (19, 20; 29, 34) in the adjacently disposed state form rectangular or quadratic apertures into which the profile tubes (4t 4_@...) are fluid-tightly and positively bonded by root ends (10, 10') of correspondingly adapted shape;

- the root ends (10, 10') of the profile tubes (4 4@) are disposed longitudinally centrally in respectively oblique planes (M) of division which extend parallel with the joint faces (17, 19; 30, 31) of the elements (18, 20; 29, 34) and being shaped so that they are rotated concentrically by in each case identical angles of inclination (a) in respect of the major axis (A) of the elliptical cross-section of an associated profile tube (4).

2. A heat exchanger according to Claim 1, characterised in that each profile tube (4t 4@, 4#) has on the inflow and outflow sides a profile end edge which essentially projects beyond the relevant root end (10).

3. A heat exchanger according to Claim 1 or 2, in which a plurality of rows of profile tubes (4; 4@, 4#) are disposed at uniform distances from one another - in each case at the same angle (R) of profile inclination and have their respective major axis (A) of the ellipse disposed towards the relevant transverse central plane (E) through the collecting or distributing tube, characterised in that the angle of inclination (a) between the relevant root ends (10) and the major axes (A) of the ellipse shape of the associated profile tubes (

, 4@, 4#) defines at the same time the angle of attack (p) of a plane (M) of division and, identical to this latter, the angle of incidence (p) of the mutual element joint surface planes to the transverse central plane (E) of the collecting or distributor tube.

4. A heat exchanger according to Claim 2 or 3, characterised in that the root ends (10) are shaped to be so rotated about the angle (a) that a central plane through the associated profile tube (

4@, 4#) which coincides with the path of whichever is the major axis (A) of the ellipse intersects the associated root ends (10) in a substantially diagonal fashion.

5. A heat exchanger according to one or more of Claims 1 to 4, characterised in that in each case two elements (21, 22) are pre-profiled along the inner reciprocal joint faces to form rectangular or quadratic apertures for the root ends (10) while they are smooth-walled along the outer ends or joint faces (23, 24).

6. A heat exchanger according to Claim 5, characterised in that there are formed between the outer end faces of two adjacent elements (21, 22) upwardly open joints (27), lip-like projections (25, 26) on the elements providing the joint surfaces.

7. A heat exchanger according to Claim 5 or 6, characterised in that two adjacent elements (21, 22) are adjacently disposed and centred by means of webs (28) which engage under one another on the inside of the collecting or distributing tube.

8. A heat exchanger according to one or more of Claims 1 to 4 as well as Claims 6 and 7, characterised in that in each case one element (29) along joint faces (30, 31) at both ends is constructed with outwardly open rectangular or quadratic recesses (32) for the relevant profile tube root ends (10), and of which in each case one open root end side is masked by strip-like connecting elements (33, 34) along the joint faces (30, 31) at both ends, the element (29), the connecting elements (33, 34) and the root ends (10) together with associated profile tubes (

4@, 4#) in each case forming one independent assembly unit.

9. A heat exchanger according to one or more of Claims 2 to 7, characterised in that in each case two elements (21, 22) together with the root ends (10) of . the profile tubes (

4₂. 4#) anchored in them form an independent assembly unit.

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