EP0475817B1 - Heat exchanger for combination boilers - Google Patents

Abstract

The heat exchanger for a combination hot-water boiler comprises rectilinear sections (1, 2) juxtaposed two by two and forming part respectively of two separate pipes, the double sections obtained (T) being mounted parallel to one another with transverse metal plates (3) interposed. The outlets of the two rectilinear sections making up each double section are staggered in relation to one another, thus defining a long end (A) and a short end (B), and there is provided at each end of the bundle of double sections a connection box (4), the interior of which is divided into two stages (41, 42) assigned respectively to the two pipes by exclusive impermeable connection to these two stages respectively of the long ends (A) and of the short ends (B), each stage itself being subdivided into compartments (411, 412 etc.; 421, 422 etc.) each assigned to the individual connection of two rectilinear sections forming part of the same pipe. <IMAGE>

Description

The invention relates to heating bodies equipping mixed hot water boilers, that is to say intended to heat water in two conduits forming respectively part of a closed central heating circuit and a circuit of drawing hot water for cooking, toilet ... the water thus drawn being called "sanitary water" in what follows.

It is more particularly aimed, among these heating bodies, those for which the two hot water pipes respectively comprise rectilinear sections juxtaposed two by two, the double sections obtained being mounted parallel to one another with the interposition of transverse metal plates forming both spacers and heat exchange fins, the consecutive rectilinear sections of each duct being connected two by two to the ends of these sections using appropriate fittings.

In the known embodiments of these heating bodies, the fittings in question are generally tubular bends in a U shape: see for example patent FR-A-1 332 607 or FR-A-2 404 179.

The manufacture of these elbows and their tight assembly to the straight sections to be connected to each other are delicate and costly, especially when the profile of said sections differs from the circle.

The object of the invention is, above all, to improve these mutual connections from the point of view in particular of the simplicity of manufacture, of sealing and of longevity.

To this end, the heating bodies of the kind in question according to the invention are essentially characterized in that the mouths of the two sections straight lines making up each double section are offset longitudinally with respect to each other, thus defining a long end and a short end and in that there is provided at each end of the bundle composed by the parallel double sections a transverse housing of connection, the interior of which is divided into two stages respectively assigned to the two conduits by sealed connection exclusive to these two stages respectively of the long ends and of the short ends defined above, each stage being itself subdivided into compartments each assigned to the individual connection from a straight section to the adjoining straight section forming part of the same duct.

• la portion courante de chaque tronçon double se présente sous le forme d'un cylindre dont la directrice est une courbe fermée continue C symétrique par rapport à un plan vertical longitudinal, chaque tronçon double est aménagé de façon à présenter un contour transversal s'étendant selon la courbe C, non seulement au niveau du bout de chacune de ses extrémités courtes, mais également au niveau du bout de chacune de ses extrémités longues, et le boîtier est évidé dans sa paroi disposée du côté des tronçons et dans sa cloison intermédiaire séparant les deux étages, par des lumières dont le bord s'étend selon la courbe C, lumières propres à recevoir jointivement, respectivement, les bouts d'extrémités courtes et les bouts d'extrémités longues,
• le boîtier est constitué par deux demi-coquilles métalliques dont les bords évasés vers l'extérieur sont rapportés l'un contre l'autre avec interposition d'une plaque perforée constituant la cloison intermédiaire,
• des doubles bossages formés dans la paroi latérale du boîtier définissent à l'intérieur de ce boîtier des gorges servant de logements jointifs à des bords de cloisons planes délimitant les différents compartiments de ce boîtier.

In preferred embodiments, use is also made of one and / or the other of the following arrangements:

• the current portion of each double section is in the form of a cylinder whose directrix is a continuous closed curve C symmetrical with respect to a longitudinal vertical plane, each double section is arranged so as to have a transverse contour extending along curve C, not only at the end of each of its short ends, but also at the end of each of its long ends, and the housing is hollowed out in its wall arranged on the side of the sections and in its intermediate partition separating the two stages, by lights whose edge extends according to curve C, lights suitable for receiving contiguously, respectively, the ends of short ends and the ends of long ends,
• the housing is constituted by two metal half-shells, the edges of which are flared towards the outside are brought together against one another with the interposition of a perforated plate constituting the intermediate partition,
• double bosses formed in the side wall of the housing define inside this housing grooves serving as contiguous housings at the edges of flat partitions delimiting the various compartments of this housing.

The invention includes, apart from these main provisions, certain other provisions which are preferably used at the same time and which will be more explicitly discussed below.

In what follows, a preferred embodiment of the invention will be described with reference to the accompanying drawings in a manner which is of course not limiting.

Figure 1 of these drawings shows schematically for the purpose of explanation, a portion of a heating body for a mixed boiler established according to the invention.

Figure 2 shows in section on II-II Figure 3 a portion of such a heater established according to the invention.

Figures 3 and 4 are sections of Figure 2 along III-III and according to IV-IV

Finally, Figure 5 is a partial section of Figure 3 along V-V.

In a manner known per se, the heating body considered here is intended to equip a mixed boiler, that is to say capable of heating water circulating in two separate circuits, namely a first closed central heating circuit comprising in particular radiators and a circulation pump and a circuit for drawing sanitary water.

Each of these circuits comprises, in the heating body, a conduit intended to receive the calories coming from the combustion of an appropriate fuel, generally gaseous.

The one, of these conduits, which is assigned to the central heating, comprises a plurality of elementary rectilinear sections 1, and the other, assigned to the heating of sanitary water, comprises a plurality of rectilinear sections 2.

In a manner still known per se, the sections 1 and 2 are joined in pairs, each pair forming a double T section.

These double sections T are arranged in parallel with each other with the interposition of transverse plates 3 forming both spacers and heat exchange fins, all of these sections and these fins forming a sort of grid generally disposed horizontally above flames generated by the boiler burner, so as to be traversed by the corresponding hot gases and to collect the calories which they carry.

The invention relates more particularly to the mutual connections of the ends of the sections T.

• on décale longitudinalement l'une par rapport à l'autre les embouchures des deux tronçons 1 et 2 composant un même tronçon double T, ce qui définit à chaque extrémité de tronçon double une extrémité longue A et une extrémité courte B,
• et l'on prévoit à chaque extrémité du faisceau tubulaire composé par les tronçons doubles T parallèles un boîtier transversal de raccordement 4.

These connections are obtained here by implementing the following arrangements:

• the mouths of the two sections 1 and 2 making up the same double T section are displaced longitudinally relative to each other, which defines at each end of the double section a long end A and a short end B,
• and a transverse connection box 4 is provided at each end of the tube bundle made up of the parallel double sections T.

The interior of this box 4 is divided by a transverse intermediate partition 5 into two stages 4₁ and 4₂ juxtaposed in the longitudinal direction of the double sections T.

These two stages 4₁ and 4₂ are assigned respectively to the connection of the sections 1 making up the heating duct and to that of the sections 2 making up the drawing duct.

To this end, the long A and short B ends defined above are connected respectively to these two stages 4₁ and 4₂.

• chaque ensemble composé par une extrémité longue A et une extrémité courte B juxtaposées l'une contre l'autre traverse jointivement une lumière 6 complémentaire évidée dans la paroi transversale 7, du boîtier 4, disposée du côté des tronçons T et est relié de façon étanche au bord de cette lumière, notamment par soudage,
• chaque extrémité longue A traverse en outre de part en part l'étage 4₂ puis, jointivement, une lumière 8 complémentaire évidée dans la cloison 5 et est reliée de façon étanche au bord de cette lumière 8, notamment par soudage.

More precisely :

• each assembly made up of a long end A and a short end B juxtaposed one against the other contiguously crosses a complementary lumen 6 hollowed out in the transverse wall 7, of the housing 4, arranged on the side of the sections T and is tightly connected at the edge of this light, in particular by welding,
• each long end A further passes right through the stage 4₂ then, contiguously, a complementary light 8 hollowed out in the partition 5 and is connected in a sealed manner to the edge of this light 8, in particular by welding.

In addition, each stage 4₁, 4₂ is subdivided into compartments 4₁₁, 4₁₂ ..., 4₂₁, 4₂₂ ... which are each assigned to the individual connection of a straight section 1 or 2 to the contiguous straight section 1 or 2 forming part of the even drove.

This subdivision into compartments is carried out using flat partitions 9, 10 which extend parallel to the longitudinal direction of the double T sections.

As can be clearly seen in FIG. 1, in each of the current compartments there emerge two elementary straight sections 1 or 2, namely a water inlet section and a water outlet section.

The partitions 9 and 10 which respectively line the two stages 4₁ and 4₂ are preferably alternated transversely, as illustrated, but such alternation is not essential.

After establishing the respective connections between the different sections 1 and 2 in the manner explained above, the circulation of the water in these different sections can be made according to the arrows F1 and F2 for each of the two conduits from one end to the other of the heating body, the arrows F1 corresponding here to the heating water and the arrows F2, to the domestic water .

In the example illustrated, the circulations are made against the current, but they could also be provided with currents of the same direction.

We also see in Figure 1 that the compartment 4 le corresponding to one end of the housing 4 exclusively serves a straight section 1: it is assigned to the arrival of the heating water in the heater, which is introduced into this compartment 4₁₁ through a nozzle 11.

In the embodiment which has been illustrated in FIGS. 2 to 5, the current portion of each double T section is in the form of a cylinder whose directrix is a continuous closed curve C (FIGS. 4 and 5) not having no re-entrant angle and symmetrical with respect to a longitudinal vertical plane.

This curve C advantageously has the general shape of a flattened ellipse.

In this case, the profile of each of the two rectilinear sections 1 and 2 corresponds to one half, of the overall profile, lying on one side of the major axis of said curve.

As can be seen in FIG. 4, such a profile, in the form of a D, has angular points and it is difficult to obtain a sealed connection between the periphery of a part thus profiled and a complementary opening hollowed out in a sheet.

This is why, according to an advantageous arrangement of the invention, each sealed assembly is produced between a light (6,8) hollowed out in a wall or partition (7,5) of the housing 4 and an end (A, B) of section introduced into this light according to a curve continuous without angular point presenting exactly the shape and the dimensions of the curve C above.

This result is obtained automatically at the level of the lights 6, since the double T sections are still complete at this level.

To obtain the same result at the lights 8 passing through the intermediate partition 5, the long ends A are deformed so as to restore the desired profile at the right of its mouth, as can be seen in FIGS. 1 to 4.

To this end, preferably, the procedure is as follows.

The double sections T are established in the manner explained in patent application FR-A-2 645 633 published on 12.10.90 by the applicant in the sense that each double section comprises in its median zone a metal strip 12 studded with bosses 13 the vertices of which come into contact with the facing external walls 14 (FIG. 5).

We then fold outwards each portion 12₁ of the central metal blade 12, which extends longitudinally beyond the short end B and the edge of this inclined folded edge is deformed so as to give it the profile of half of the overall contour of section T.

Under these conditions, each of the openings 6 and 8 hollowed out in the partitions 7 and 5 and intended to receive joined a long end A or short B of tubular section, has an elliptical contour or the like which is relatively easy to form and along which can be obtained by welding or the like a very tight connection.

• sur les figures 2, 3 et 4, des bossages 15 formés par paires dans les parois latérales du boîtier 4 et définissant entre eux des gorges propres à recevoir jointivement des bords de cloisons 9 ou 10,
• sur les mêmes figures 2, 3 et 4, la constitution du boîtier 4 en deux demi-coquilles 16 et 17 présentant des bords évasés 18 rapportés les uns contre les autres avec interposition de la cloison intermédiaire 5,
• sur les figures 2, 3 et 5, un mode de réalisation des polaques d'entretoisement 3, qui sont avantageusement constituées par des feuilles minces en acier inoxydable dont la surface est parsemée de portions crevées ou semi-découpées 19 formant des canaux à parois discontinues qui présentent une bonne surface d'échange thermique sans pour autant opposer une forte perte de charge aux gaz chauds dont les calories doivent être transmises à l'eau à chauffer.

We still see:

• in FIGS. 2, 3 and 4, bosses 15 formed in pairs in the side walls of the housing 4 and defining between them grooves suitable for receiving joined edges of partitions 9 or 10,
• in the same FIGS. 2, 3 and 4, the constitution of the housing 4 into two half-shells 16 and 17 having flared edges 18 fitted against each other with the interposition of the intermediate partition 5,
• in FIGS. 2, 3 and 5, an embodiment of the spacer poles 3, which advantageously consist of thin sheets of stainless steel whose surface is dotted with punctured or semi-cut portions 19 forming channels with discontinuous walls which have a good heat exchange surface without opposing a strong pressure drop to the hot gases, the calories of which must be transmitted to the water to be heated.

In general, and as said above, the whole of the heating body extends horizontally and the same is true for each of the two side boxes 4.

In other words, the largest dimension of each housing, parallel to the intermediate partitions 5, extends from the front to the rear of the boiler.

Advantageously takes advantage of this orientation to open horizontally towards the rear of the heating body all of the four connections serving the latter in water.

Thus the compartment 4₁₁ in which the heating water is admitted is connected to such a rear connection 11 by a tube 20 (Figures 2 and 3) horizontally passing through all the partitions 9 and that the compartment 4 _2n (not shown , n denoting the number of compartments of the housing 4 considered assigned to the drawing-off water) is also served by such a rear connection 21.

This measure makes it very easy to connect the heating element, like a drawer, to pipes pending, by simple horizontal movement of this body towards the rear, so as to make the end pieces 11 and 20 cooperate with complementary end pieces provided at the ends of said pipes and fitted with appropriate seals.

As a result of this, and whatever the embodiment adopted, there are finally heating bodies for mixed boilers whose constitution results sufficiently from the above.

These heating bodies have many advantages compared to those previously known, in particular with regard to the simplicity of manufacture, sealing and robustness.

Claims (5)

1. A heat exchanger for a combination hot water boiler for heating water in two separate circuits comprising straight sections (1, 2) juxtaposed in pairs and forming parts of the two circuits respectively, the resulting double sections (T) being mounted parallel to one another with the interposition of transverse metal plates (3), the consecutive straight sections of each circuit being connected two-by-two at their ends by means of suitable connections, characterized in that the openings of the two straight sections (1,2) forming each double section (T) are offset longitudinally relative to one another so as to define a long end (A) and a short end (B) and in that a transverse connecting casing (4) is provided at each end of the bundle formed by the parallel double sections (T) with its interior divided into two stages (4₁, 4₂) assigned to the two circuits respectively by sealed connection to these two stages respectively of the long ends (A) and the short ends (B) defined above, each stage being itself divided into compartments (4₁₁, 4₁₂ ; 4₂₁, 4₂₂...) each assigned to the individual connection of a straight section to the adjacent straight section forming part of the same circuit.
2. A heat exchanger according to claim 1, characterized in that the main part of each double section (T) has the form of a cylinder whose generator is a continuous closed curve C symmetrical with respect to a longitudinal vertical plane, in that each double section (T) is so designed as to have a transverse outline following the curve C, not only in the region of the end part of each of its short ends (B) but also in the region of the end part of each of its long ends (A), and in that the casing (4) is apertured in its wall (7) located adjacent the sections and in its intermediate partition (5) separating the two stages by openings (6, 7) whose edges run in accordance with the curve C and which are adapted to receive in abutment the short end parts and the long end parts respectively.
3. A heat exchanger according to claim 1 or 2, characterized in that the casing (4) is formed by two metal half shells (16, 17) whose flared out edges (18) are located against one another with the interposition of a perforated plate forming the intermediate partition (5).
4. A heat exchanger according to any of the preceding claims, characterized in that double embossments (15) formed in the sidewall of the casing (4) define grooves inside the casing serving for abutting reception of edges of flat partitions (9, 10) separating the different compartments of the casing.
5. A heat exchanger according to any of the preceding claims, characterized in that its various coupling unions (11, 20) for the external water services pipework all open horizontally and parallel to one another, towards the rear of the said exchanger.

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