EP1565690B1 - Heat exchanger and device producing domestic hot water - Google Patents

Abstract

The invention concerns a heat exchanger and a device for producing domestic hot water, comprising a chamber (5) wherein is installed said exchanger. Said device is characterized in that the exchanger comprises a coil (69) with good heat conduction helically wound, wherein the domestic water to be heated is designed to circulate, each turn (62) of the coil (69) having radial surfaces (620) which are spaced apart from the radial surfaces (620) of the turn (62) adjacent to an interstice (L) calibrated by means of a projecting helical element (64) with pitch identical to that of the coil (69), arranged between the radial surfaces (620) opposite the turns (62), said coil (69) being maintained between two coaxial cylindrical ferrules (65, 66) assembled together at their ends through two helical flanges (67, 67'), said primary fluid flowing counter-current to the domestic water, between the turns (62) of said coil (69), on either side of said projecting element (64), between said ferrules (65, 66).

Description

The present invention relates to a heat exchanger and a device for domestic production of hot water, equipped with such an exchanger.

To satisfy the need for domestic hot water inside a home, there are several technical solutions that bring more or less comfort to the user.

A first solution is to produce hot water with a balloon whose volume can vary from a few tens to a few hundred liters. The reservoir of water accumulated in this flask is heated by an electrical resistance or by a coil through which the fluid of the primary circuit of a heat exchanger of a boiler or fuel oil or gas.

The main advantage of such a balloon is that it allows to have a large flow of hot water as it is not empty, so it is possible to open at the same time several taps in the dwelling.

However, it occupies a large space in the room where it is installed. In addition, it requires a significant warm-up time if it has been completely emptied and its cost price is expensive.

A second technical solution is the so-called "instant" production of domestic hot water, that is to say as and when required.

The Figures 1 and 2 attached to this patent application are diagrams which illustrate a domestic installation according to the state of the art, allowing such instantaneous production of hot water.

This comprises a primary central heating circuit I and a secondary sanitary drawing circuit II , which interfere with one another at a device D for producing hot water. The latter comprises a small volume balloon B containing a coil S, of circular section, at which heat exchange occurs.

The primary circuit I comprises a heating source 1 of the water of this circuit; it is for example a boiler provided with a gas burner.

A suitable pump 15 ensures the circulation of water in this circuit I.

The water leaves the boiler 1 via a pipe 10, then passes via a "T" -shaped connection R in a pipe 11, passes through the radiators of the central heating 100, and returns to the boiler 1 after having dissipated part of its calories in the radiators 100.

The return pipework comprises two pipes 12, 13 separated by a three-way valve V ; the pipe 13 is connected to the boiler 1 after passing through the pump 15 via a pipe 14.

In this application, the central heating water constitutes the primary fluid; the hot water production device D is connected in parallel with the radiators 100, the bypass being upstream of these radiators via the " R " connection "T" and, downstream, by the three-way valve V.

The references a and b designate the inlet and outlet orifices for the primary fluid inside the hot water production device D.

The "T" connector R is connected to the inlet port a by a pipe 16; the outlet orifice b is connected to the three-way valve V via a pipe 17.

On the secondary circuit II , reference EF has been designated a source of cold water production; it may be for example a tap connected to the drinking water network provided in the dwelling receiving this installation.

EC has designated a device for using hot water; it is for example a faucet or a shower head for supplying hot water to the user.

The references c and d denote the inlet and, respectively, outlet mouths of the secondary fluid, here the water of the sanitary circuit.

The source EF is connected to the mouth c by a cold water supply pipe 19, while the outlet mouth d is connected to the hot water utilization device EC by a water distribution pipe hot 18.

In the state of the circuits illustrated on the figure 1 only the primary heating circuit I is in use.

The three-way valve V is in a position such that the lines 12 and 13 are placed in communication, the pipe 17 being on the other hand insulated.

In this situation, the water supplied by the boiler 1 travels exclusively to the primary circuit I , as symbolized by the arrows F , by heating the radiators 100.

The figure 2 illustrates the situation in which a draw of domestic water is required, for example by the opening of a valve provided in the EC use device.

This drawing automatically switches, via a suitable control system known per se, the three-way valve V , so as to close the outlet of the pipe 12, while providing the communication of the pipe 17 with the pipe 13.

Under these conditions, the hot water flowing along the arrow G in the primary circuit I is switched at the connection "T" R to the hot water production device D.

It travels the ball B from its entrance to its exit b , following a sinuous path through the coils of the coil S.

The hot water does not pass through the radiators 100 since the outlet of the pipe 12 is closed, but only inside the tank B and returns to the boiler 1, via the lines 13 and 14 and the pump 15.

Simultaneously, because of the call for domestic water, the water of the secondary circuit II travels the coil S of the entry c to the exit d , as symbolized by the arrows H , that is to say against -current of the water of the primary circuit circulating in the balloon B.

The heat exchange takes place between the hot water of the primary circuit present inside the balloon B and the cold water penetrating inside the coil S ; it is therefore hot water that reaches the use device EC .

As an indication, the water leaves the boiler 1 at a temperature of about 80 ° C and returns to a temperature between 40 and 60 ° C depending on the setting of the radiators 100.

In the secondary circuit II , the cold water entering inside the coil S is at a temperature of the order of 15 ° C and the hot water obtained inside the utilization device EC is at a temperature of the order of 45 ° C.

When the drawing is completed, the three-way valve V switches back to its initial position, which makes it possible to supply the radiators 100.

The instantaneous flow rate of hot water that can be obtained continuously with such an installation depends on the thermal exchange performance of the device D. But these are not optimal because the coil S is circular right section. As a result, it is impossible to obtain hot water from several taps at the same time.

In addition, the coil S tends to scale up quickly.

In addition, the axial size of a coil of round section is important, so that the dimensions of the balloon B containing it are also.

In addition, the three-way valve V also has a large footprint.

Finally, the price of such a valve and its connections and connecting tubes to the hot water production device D is important in the total cost of the installation.

We already know from the document FR-A-2,337,314 a heat exchanger comprising a tube of thermally good conducting material wound helically to form a coil, in which a so-called "secondary" fluid is intended to circulate, this coil being held between two cylindrical, coaxial, so-called "internal" rings "and" outer ", assembled together at each of their two ends, said coil having a flattened cross section, whose major axis is substantially perpendicular to the axis of the helix, each turn of the coil having radial faces which are spaced from the radial faces of the adjacent turn of a gap of constant width, a so-called "primary" fluid being intended to circulate between each turn of said coil, against the flow of said secondary fluid flow.

Such a device is of a large size and is also poorly adapted to withstand the overpressures likely to appear in the fluid circulation circuit.

The present invention aims to solve the aforementioned drawbacks of the state of the art.

It aims in particular to provide a heat exchanger with a large exchange surface, and a hot water production device instantly ensuring a large flow of hot water.

Another object of the invention is to integrate within the enclosure of the hot water production device a three-way valve system of very simple structure, so as to significantly reduce the overall cost of production. this device, and to significantly reduce the overall size.

Another objective of the invention is to provide a device with a high resistance to the sanitary pressure which can sometimes reach 25 bars (25.10 ⁵ Pa), these pressure peaks may be the result of "water hammer" or pressure valves. defective security, for example.

To this end, the invention relates to a heat exchanger comprising a tube of thermally good conductive material, helically wound to form a coil, wherein a fluid, called "secondary", is intended to circulate, this coil being maintained between two cylindrical, coaxial, so-called "internal" and "external" ferrules, assembled together at each of their two ends, said coil having a flattened and substantially oval cross-section, whose major axis is substantially perpendicular to the axis of the helix each coil coil having radial faces which are spaced apart from the radial faces of the adjacent turn of a gap of constant width, a so-called "primary" fluid being intended to circulate between each turn of said coil, against the current of the circulation said secondary fluid.

This exchanger is remarkable in that the gap between two adjacent coils of the coil is calibrated by means of at least one helical protruding element, as well as the coil and arranged between the radial faces facing each other of the turns, and in that the inner ferrule and the outer ferrule are assembled together at each of their two ends by a helical flange whose space between the ends of the coil allows the passage of said primary fluid and its circulation between the turns of said coil of part and of another of said projecting element, between said ferrules.

• ledit élément saillant est embouti dans l'une des faces radiales des spires du serpentin et vient au contact de la face radiale de la spire voisine située en regard ;
  • au moins un élément saillant est embouti dans l'une des faces radiales des spires et un nombre identique d'éléments saillants est embouti dans l'autre face radiale de la spire, chaque élément saillant de l'une des faces radiales venant au contact d'un autre élément saillant de la face radiale située en regard ;
  • une première paire de saillies semi-cylindriques est emboutie dans l'une des faces radiales des spires et une seconde paire de saillies semi-cylindriques est emboutie dans l'autre face radiale desdites spires, chaque saillie de l'une des faces radiales venant au contact d'une autre saillie de la face radiale située en regard ;
  • ledit élément saillant est un fil rigide, hélicoïdal, monté de façon que chacune de ses spires soit intercalée entre deux spires voisines du serpentin,
  • les petits côtés opposés de chaque spire du serpentin sont brasés avec la virole interne et la virole externe au niveau de leurs points de contact respectifs avec celles-ci.

According to other non-limiting features of the invention:

• said projecting element is stamped into one of the radial faces of the coils of the coil and comes into contact with the radial face of the adjacent turn facing it;
  • at least one projecting element is stamped into one of the radial faces of the turns and an identical number of projecting elements is stamped into the other radial face of the turn, each projecting element of one of the radial faces coming into contact with another element projecting from the radial face situated opposite;
  • a first pair of semi-cylindrical projections is stamped into one of the radial faces of the turns and a second pair of semi-cylindrical projections is stamped into the other radial face of said turns, each projection of one of the radial faces coming to contact with another projection of the radial face situated opposite;
  • said projecting element is a helical rigid wire mounted so that each of its turns is interposed between two adjacent turns of the coil,
  • the opposite small sides of each turn of the coil are brazed with the inner ferrule and the outer ferrule at their respective points of contact therewith.

The invention also relates to a domestic hot water production device which is characterized in that it comprises an enclosure inside which is installed the aforementioned heat exchanger, the sanitary water to be heated constituting the fluid secondary coil circulating inside the coil, each end of this coil passing through the wall of said enclosure at a mouth formed for this purpose, the inlet and the outlet of the primary fluid inside the enclosure is making respectively an inlet port and an outlet port.

• une chambre de répartition du fluide primaire est ménagée à l'intérieur de ladite enceinte, cette chambre étant délimitée par la paroi intérieure de la virole interne cylindrique et par un fond circulaire obturant de façon étanche l'extrémité de ladite virole interne située au voisinage de l'orifice d'entrée du fluide secondaire, dite "extrémité d'entrée" et un tube d'introduction du fluide primaire est disposé à l'intérieur de ladite virole interne, l'une de ses extrémités étant reliée à l'orifice d'entrée du fluide primaire et son extrémité opposée débouchant à faible distance dudit fond, de sorte que ce dernier forme un déflecteur qui renvoie le flux entrant de fluide primaire en direction de l'extrémité opposée de ladite chambre de répartition ;
• le fond est concave, sa concavité étant orientée en direction du tube d'introduction du fluide primaire ;
• le dispositif de production d'eau chaude comprend une tubulure à trois voies intégrée à ladite enceinte, dont l'une des voies est constituée par l'orifice d'entrée du fluide primaire, l'autre par une embouchure amont et la troisième par une embouchure aval, ledit orifice d'entrée étant muni d'un filtre ;
• cette tubulure à trois voies est munie intérieurement, au voisinage de l'orifice d'entrée, d'une lèvre déflectrice permettant de diriger le flux entrant de fluide primaire, en direction dudit orifice d'entrée ;
• le dispositif de production d'eau chaude comprend une vanne à trois voies pour la distribution du fluide primaire, intégrée à ladite enceinte, dont l'une des voies est constituée par un orifice de sortie du fluide primaire, l'autre voie débouche dans une embouchure aval et la troisième débouche dans une embouchure amont, ces deux embouchures étant ménagées dans la paroi de l'enceinte, cette vanne comportant un clapet apte à obturer sélectivement soit ledit orifice de sortie, soit la voie débouchant dans l'embouchure amont ;
• ce clapet est monté sur un arbre entraîné en rotation par un moteur ;
• un canal de décharge est ménagé à l'intérieur de l'enceinte de façon à mettre en communication de fluide l'entrée et la sortie de fluide primaire, ce canal de décharge étant équipé d'un clapet de décharge ;
• le canal de décharge est ménagé entre un renfoncement de l'enceinte et une cloison intermédiaire disposée entre ledit renfoncement et la virole externe, ce canal de décharge s'étendant depuis le voisinage de l'extrémité amont de l'enceinte jusqu'à son extrémité aval où il débouche dans l'embouchure aval de la vanne à trois voies ;
• le clapet de décharge comprend un piston sollicité par un ressort taré, apte à obturer un orifice de passage du fluide primaire ménagé dans ledit canal de décharge lorsque la pression dudit fluide primaire arrivant à l'intérieur de l'enceinte est inférieure à une valeur seuil prédéterminée et qui, au contraire, autorise ce passage lorsque la pression excède cette valeur ;
• le clapet de décharge est monté dans un manchon solidaire du renfoncement de l'enceinte et dont l'axe est perpendiculaire au plan de ce renfoncement, le piston étant mobile en translation selon ledit axe du manchon et étant sollicité par un ressort de compression hélicoïdal qui prend appui contre une pièce en forme de dôme fixée de manière étanche audit manchon ;
• le clapet de décharge comprend une cloison transversale fixe séparant l'espace entre ledit renfoncement de l'enceinte et la cloison intermédiaire et une embase solidaire de cette cloison fixe qui est traversée d'un côté par l'orifice susceptible d'être obturé par ledit piston et de l'autre par une ouverture qui communique en permanence avec l'intérieur de la pièce en forme de dôme ;
• l'enceinte est réalisée en matière plastique ;

Moreover, according to a number of other non-limiting features of the invention, taken alone or in combination:

• a primary fluid distribution chamber is provided inside said chamber, this chamber being delimited by the inner wall of the cylindrical inner shell and by a circular bottom sealingly closing the end of said inner shell located in the vicinity of the inlet orifice of the secondary fluid, called "inlet end" and a tube for introducing the primary fluid is disposed inside said inner shell, one of its ends being connected to the inlet of the primary fluid and its opposite end opening at a short distance from said bottom, so that the latter forms a deflector which returns the incoming flow of primary fluid to the opposite end of said distribution chamber;
• the bottom is concave, its concavity being oriented toward the introduction tube of the primary fluid;
• the hot water production device comprises a three-way pipe integrated in said chamber, one of which is constituted by the inlet of the primary fluid, the other by an upstream mouth and the third by a downstream mouth, said inlet port being provided with a filter;
• this three-way manifold is provided internally, in the vicinity of the inlet orifice, with a deflecting lip making it possible to direct the incoming flow of primary fluid towards said inlet orifice;
• the hot water production device comprises a three-way valve for the distribution of the primary fluid, integrated in said chamber, one of which is constituted by an outlet orifice of the primary fluid, the other channel opens into a downstream mouth and the third opens into an upstream mouth, these two mouths being formed in the wall of the enclosure, this valve comprising a valve adapted to selectively close either said outlet orifice or the channel opening into the upstream mouth;
• this valve is mounted on a shaft driven in rotation by a motor;
• a discharge channel is provided inside the enclosure so as to put in fluid communication the inlet and the primary fluid outlet, this discharge channel being equipped with a discharge valve;
• the discharge channel is formed between a recess of the enclosure and an intermediate partition disposed between said recess and the outer shell, this discharge channel extending from the vicinity of the upstream end of the enclosure to its end downstream where it opens into the downstream mouth of the three-way valve;
• the discharge valve comprises a piston biased by a calibrated spring, adapted to close a primary fluid passage opening in said discharge channel when the pressure of said primary fluid arriving inside the enclosure is below a threshold value predetermined and which, on the contrary, allows this passage when the pressure exceeds this value;
• the discharge valve is mounted in a sleeve integral with the recess of the chamber and whose axis is perpendicular to the plane of this recess, the piston being movable in translation along said axis of the sleeve and being urged by a helical compression spring which bears against a dome-shaped piece sealingly attached to said sleeve;
• the discharge valve comprises a fixed transverse partition separating the space between said recess of the enclosure and the intermediate partition and a base integral with this fixed partition which is traversed on one side by the orifice which can be closed by said piston and the other through an opening that communicates permanently with the interior of the dome-shaped piece;
• the enclosure is made of plastic;

Finally, the invention also concerns a mixed domestic hot water distribution installation comprising a primary central heating circuit and a secondary sanitary drawing circuit, this installation being equipped with a hot water production device such as the one mentioned above. above, connected in parallel to the radiators of the central heating circuit, the central heating water, supplied by a boiler, constituting said primary fluid and the sanitary draw water constituting said secondary fluid.

• les figures 1 et 2 sont des schémas illustrant le principe de fonctionnement d'une installation de chauffage mixte, équipé d'un dispositif de production d'eau chaude sanitaire instantanée, conforme à l'état de la technique ;
• la figure 3 est une vue en perspective éclatée des différentes pièces constitutives du dispositif de production d'eau chaude ;
• la figure 4 est une vue en coupe verticale longitudinale du dispositif de production d'eau chaude conforme à l'invention ;
• la figure 5 est une vue en coupe longitudinale de ce même dispositif, prise selon le plan de coupe représenté par la ligne V-V sur la figure 4 ;
• la figure 6 est une vue schématique représentant les deux viroles de l'échangeur de chaleur en coupe transversale ;
• les figures 7, 8 et 9 sont des vues en coupe verticale transversale du dispositif de la figure 4, selon les plans de coupe représentées respectivement par les lignes VII-VII, VIII-VIII et IX-IX de la figure 4, la figure 7 représentant en outre les embouchures d'entrée et de sortie de serpentin vues en coupe axiale ;
• la figure 10 est une vue en perspective de l'une des pièces de la vanne à 3 voies ;
• la figure 11 est une vue en perspective de l'extrémité aval du dispositif de production d'eau chaude ;
• la figure 12 est une vue en coupe agrandie du clapet de décharge du dispositif de la figure 4, prise selon le plan de coupe représenté par la ligne XII-XII sur cette figure ;
• les figures 13 et 14 sont des vues en coupe du même clapet de décharge dans le plan de la figure 4, respectivement en positions fermée et ouverte ;
• la figure 15 est une vue de dessus partiellement en coupe du dispositif de la figure 4 ;
• la figure 16 est une vue en coupe verticale longitudinale d'une variante de réalisation du dispositif de production d'eau chaude ;
• la figure 17 est un schéma d'une installation domestique équipée du dispositif de production d'eau chaude sanitaire selon l'invention, celui-ci étant représenté en coupe ;
• la figure 18 est une vue en coupe verticale longitudinale d'une variante de réalisation du dispositif de production d'eau chaude ;
• la figure 19 est une vue en coupe longitudinale de ce même dispositif, prise selon le plan de coupe représenté par la ligne XIX-XIX sur la figure 18;
• la figure 20 est une vue en bout de l'échangeur de chaleur des figures 18 et 19 ;
• la figure 21 est une vue en coupe longitudinale, partielle, représentant une variante de réalisation du serpentin ;
• la figure 22 est une vue en perspective de l'extrémité aval du dispositif de production d'eau chaude représenté sur les figures 18 et 19 ;
• la figure 23 est une vue en coupe longitudinale, partielle, d'une variante de réalisation du dispositif de l'échangeur de chaleur représenté sur la figure 18, ce dernier étant hors de l'enceinte du dispositif de production d'eau chaude ; et
• la figure 24 est une vue en coupe verticale longitudinale d'une variante de réalisation du dispositif de production d'eau chaude représenté sur la figure 16 ;
• la figure 25 est une vue en coupe longitudinale, partielle, représentant une autre variante de réalisation du serpentin.

Other features and advantages of the invention will appear on reading the description which will now be made with reference to the accompanying drawings:

• the Figures 1 and 2 are diagrams illustrating the principle of operation of a mixed heating installation, equipped with a device for instantaneous domestic hot water production, according to the state of the art;
• the figure 3 is an exploded perspective view of the various constituent parts of the hot water production device;
• the figure 4 is a vertical longitudinal sectional view of the hot water production device according to the invention;
• the figure 5 is a longitudinal sectional view of this same device, taken along the section plane represented by the line VV on the figure 4 ;
• the figure 6 is a schematic view showing the two rings of the heat exchanger in cross section;
• the figures 7 , 8 and 9 are cross-sectional vertical views of the device of the figure 4 , according to the sectional planes represented respectively by the lines VII-VII , VIII-VIII and IX-IX of the figure 4 , the figure 7 further illustrating the serpentine inlet and outlet mouths as seen in axial section;
• the figure 10 is a perspective view of one of the parts of the 3-way valve;
• the figure 11 is a perspective view of the downstream end of the hot water production device;
• the figure 12 is an enlarged sectional view of the discharge valve of the device of the figure 4 , taken along the plane of section represented by line XII-XII in this figure;
• the Figures 13 and 14 are sectional views of the same relief valve in the plane of the figure 4 respectively in closed and open positions;
• the figure 15 is a top view partially in section of the device of the figure 4 ;
• the figure 16 is a vertical longitudinal sectional view of an alternative embodiment of the hot water production device;
• the figure 17 is a diagram of a domestic installation equipped with the device for producing domestic hot water according to the invention, the latter being shown in section;
• the figure 18 is a vertical longitudinal sectional view of an alternative embodiment of the hot water production device;
• the figure 19 is a longitudinal sectional view of this same device, taken along the section plane represented by the line XIX-XIX on the figure 18 ;
• the figure 20 is an end view of the heat exchanger of the figures 18 and 19 ;
• the figure 21 is a partial longitudinal sectional view showing an alternative embodiment of the coil;
• the figure 22 is a perspective view of the downstream end of the hot water production device shown in FIGS. figures 18 and 19 ;
• the figure 23 is a longitudinal sectional view, partial, of an alternative embodiment of the device of the heat exchanger shown in FIG. figure 18 the latter being outside the enclosure of the hot water production device; and
• the figure 24 is a vertical longitudinal sectional view of an alternative embodiment of the hot water production device shown in FIG. figure 16 ;
• the figure 25 is a partial longitudinal sectional view showing another embodiment of the coil.

The heat exchanger 6 will now be described with reference more specifically to the figures 3 , 4 and 5 .

It consists of a tube 69 of flattened cross section and substantially oval, helically wound so as to form a coil, so that the major axis of its cross section is substantially perpendicular to the axis X-X ' of the helix.

The secondary fluid circulates inside this tube 69 and the primary fluid around it and against the current.

This tube 69 is made of a thermally good conductive material, preferably metal, for example stainless steel. It consists of a number of turns 62, whose large faces called "radial faces" referenced 620, 621 are spaced from the faces 621, 620 of the adjacent turn 62, a gap of constant width L.

The short sides of each spiral turn 62 are respectively referenced 624 for the inner side and 625 for the outer side of the coil 69.

The rectilinear end portions 63, 63 'of this tube extend tangentially outwardly of the helix and terminate in cylindrical ends forming respectively the inlet mouths 60 and the outlet mouth 61 of the secondary fluid circulating therein. . The transition between the flattened portions 63, 63 'and the cylindrical ends 61, 60 is progressively.

The gap L between two adjacent turns 62 of the coil 69 is calibrated by means of a projecting element.

According to a first variant embodiment, this projecting element is a round, rigid helical wire 64, likewise not the coil 69 and mounted so that each of its turns 640 is interposed between two adjacent turns 62 of the coil 69.

The wire 64 is made of any type of rigid material, for example plastic or metal such as steel.

The helical wire 64 is interposed between the turns of the coil 69 by screwing.

Its role is to prevent deformations of the wall of the flattened tube 69 that may result from variations in the internal pressure. In addition, it makes it possible to maintain constant the gap L between two adjacent turns 62, so that the thickness of the primary fluid blade passing between these two turns is also constant, which is essential to obtain a good performance of heat exchange between primary and secondary fluids.

Making a coil 69 of flattened section and channeling the flow of primary water between the turns and against the flow of the secondary flow ensures better heat transfer between the two fluids. The size of the coil with flattened turns 69 is thus significantly reduced for better thermal performance.

The tube or coil 69 and the rigid wire 64 wound helically, are held assembled between two cylindrical coaxial shells, called "internal" and "external" and referenced respectively 65 and 66.

The expansion efforts of the turns of the tube 69 and the wire 64 are taken up by the presence of these two rings 65, 66, made of a resistant material and preferably thermally good conductor, for example metal, especially steel.

The presence of these two thin steel rings makes it possible to reduce considerably the thickness of the wall of the coil 69. Thus, to resist without deformation at a pressure of 25 bar (25 × 10 ⁵ Pa) inside the coil 69, it is sufficient to that the wall of the latter represents a thickness of 0.5 mm instead of 1.8 to 2 mm for the same section of flattened turn if these ferrules were not present.

As it appears better on the figure 6 each inner and outer shroud 65 and 65 is made from a flat, thin plate wound on itself to form a cylinder of axis of revolution X-X ' .

This split structure provides some elasticity to the ferrules 65, 66 which behave like springs, the inner ferrule 65 having a natural tendency to deviate and the outer ferrule 66 to close on itself. When assembling the serpentine subassembly 69 / wire 64 inside the ferrules, the outer ferrule 66 is opened slightly while the inner ferrule 65 is wound tighter on itself. After assembly, the two rings 65 and 66 are released and their own elasticity brings them back to their original position represented on the figure 6 .

The two longitudinal ends 650, 660 respectively of each sheet overlap along a generatrix of the cylinder and have a recess located outside the outer shell 66 (respectively inside the inner shell 65) to maintain a constant spacing e between the two ferrules.

In addition, the inner ferrule 65 and the outer ferrule 66 take up the tensile forces of the wire 64 and the coil 69 with two flanges or crowns. metal (for example steel) 67, 67 ', assembled (preferably by welding) at each of their two ends.

As it appears on the figure 3 each flange 67, 67 'has a helical general shape at a turn, so that the two ends 674, 675, (respectively 674', 675 ') of the turn are not in the same plane and are slightly offset 1 relative to each other of a space 676, respectively 676 '. The shape of the ends of the rings 65, 66 is adapted accordingly, see figure 3 that is to say, it has a small recess 650, respectively 660.

As can be seen on the figure 5 , the flange 67 has in cross section the shape of a "U" at right angles whose straight central portion 670 is pressed against the radial face 621 of the last turn 62 of the winding 69 and whose two wings 672 are welded respectively to the outer surface of the inner ferrule 65 and to the inner surface of the outer ferrule 66.

The flange 67 ', located on the right on the figure 5 , has a similar structure.

The primary fluid enters the heat exchanger 6 tangential to the coil 69, at the space 676, between the first and second turns of the coil 69, flows on either side of the wire 64 and between the ferrules 65. , 66 and spring at the space 676 ', (arrow K , figure 22 ).

Finally, a circular bottom 68 seals the end of the inner shell 65 located in the vicinity of the inlet mouth 60 of the coil 69.

Preferably, this bottom 68 is concave and its concavity is oriented towards the inside of the shell 65 so as to define a chamber 680.

According to a second embodiment variant illustrated on the figures 18 and 19 , the projecting element calibrating the gap L consists of two protrusions 623, 623 'semi-cylindrical, the projection 623 being stamped in the radial face 621 of the turn 62 and the projection 623' being stamped in the opposite radial face 620 . Each projection 623 of the radial face 621 comes into contact with the projection 623 'of the radial face 620.

According to a third variant embodiment illustrated on the figure 25 , the projecting element calibrating the gap L consists of two pairs of semi-cylindrical projections 628, 629 and 628 ', 629', the pair of projections 628, 629 being stamped in the radial face 621 of the turn 62 and the pair of projections 628 ', 629' being embossed in the opposite radial face 620. Each projection 628 of the radial face 621 comes to contact of the projection 628 'of the radial face 620 and likewise for the projections 629 and 629'.

This variant embodiment is particularly suitable in the case where the radial faces 620, 621 of the coil are a large width LA and / or when there is a high fluid pressure in the coil. The two points of contact between two neighboring turns prevent deformation of the coil. In this embodiment, the primary fluid flows on the one hand into the space between the inner ring 65 and the projections 628, 628 'and on the other hand in the space between the outer ring 66 and the projections 629. , 629 'next to each other.

One could also consider making more than two projections on each radial face, provided to achieve the same number of projections on each side.

According to a fourth variant illustrated on the figure 21 , the projecting element is pressed only on one of the radial faces (here the face 621) of the turns 62 and comes into contact with the radial face 620 of the adjacent turn 62 located opposite. This salient element has the reference 622.

The salient elements 622, 623, 623 ', 628, 628', 629 and 629 'which have just been described can be obtained by hydroforming. For this purpose, reference may be made to the document WO-94/16272 describing this technique.

Finally, according to an alternative embodiment of the invention illustrated on the figure 23 the inner and outer short sides 624 and 625 of each turn 62 of the coil 69 are brazed at their point of contact with the inner and outer rings 65 and 66, respectively. The solders bear the respective numerals 626 and 627.

Each solder 626 and 627 has the shape of a helical band extending along the corresponding ferrule.

The brazing can be carried out by introducing copper powder on the two walls facing inner and outer shrouds 65 65 and then placing the coil 69 and placing the assembly in a vacuum oven.

The connection between the coil 69 and the two inner and outer rings 65 and 65 increases the exchange surface which is in contact with the primary fluid and the secondary fluid and thus substantially increases the overall efficiency of the exchanger while also improving its resistance. at high health pressures.

The rings 65 and 66 behave as a finned surface integral with the coil 69.

Note that although this is not represented on the figure 4 it would also be possible to make the solders 626 and 627 in the variant where the projecting element calibrating the gap L between two turns 62 is the wire 64. In this case, however, the latter must be made of metal to support the passage vacuum oven.

The invention also relates to a device 4 for producing domestic hot water water comprising an enclosure 5 inside which is installed the heat exchanger 6 which has just been described, the domestic water to be heated constituting the secondary fluid circulating inside the coil 69 of this exchanger.

Referring now to figures 3 , 4 , 5 and 7 it can be seen that the enclosure 5 has the general shape of a cylinder whose axis of revolution coincides with the axis X-X ' and whose two rounded ends 53, 54 are portions of the sphere.

The end 53 of the enclosure through which the primary fluid is introduced is called "upstream end" and its opposite end 54, "downstream end".

This enclosure 5 is made of composite material, such as a plastic material loaded for example with fibers or glass flakes, so as to give it low mechanical strength and thermal insulation properties.

It consists of two lower half-shells 51 and 52 upper, obtained by injection using molds of appropriate shapes.

The heat exchanger 6 previously described is placed inside the lower half-shell 51 provided with two mouths 510, 511 suitable for receiving respectively the cylindrical ends 60 and 61 of the coil 69, (see FIG. figure 7 ).

These tips 60 and 61 are respectively crimped on these mouthpieces 510 and 511, an O-ring 601, respectively 611, sealing between the stainless steel coil 69 and the plastic material of the enclosure 5.

The upper half-shell 52 is then assembled to form the enclosure 5.

Sealing is ensured by the hot melting of the edges of the two half-shells 51 and 52, and then by pressure or ultrasonic assembly using a suitable equipment known per se.

The plane along which the two half-shells 51 and 52 are welded is represented by the line Y-Y ' . The X-X ' axis is located in this plane.

As can be seen on the figure 4 , the outer shell 66 is positioned inside the enclosure 5 by an annular spacer 500 advantageously made of foam. This spacer 500 makes it possible to prevent a flow of parasitic water between the outer shell 66 and the wall of the enclosure 5

Referring back to figure 7 it can be seen that the wall 520 of the upper half-shell 52 has a recess 521 extending along the upper generatrix of the cylinder constituting the enclosure 5, parallel to the axis X-X ' .

An element 55 of composite material cooperates with this recess 521 to define a channel 50 whose role will be detailed later.

This element has the shape of an elongated slightly curved lamella and extends in the cylindrical portion of the enclosure 5, between the upstream end 53 at the downstream end 54 (see FIG. figures 3 and 4 ).

As it appears better on figures 7 and 12 this element 55 acting as an intermediate partition is curved so as to lie in the extension of the curvature of the hemi-cylindrical half-shell 52.

This partition 55 is welded or glued to the wall 520.

According to the invention, several hydraulic components necessary for the operation and / or connection of the hot water production device 4 to the rest of the installation are integrated into the enclosure 5, namely a three-way pipe 2, a three-way valve 7 and a relief valve 8.

This makes it possible to reduce the number of expensive additional parts and to reduce the total size of the device 4.

As can be seen on the figures 3 , 4 and 5 , the three channels of the pipe 2 are constituted by a mouth 23, called "upstream, formed in the wall of the upper half-shell 52, by a mouth 24, called" downstream ", formed in the wall of the half-shell lower 51 and through an orifice 20 pierced in a vertical intermediate partition 220, each semi-circular half of which is integral with the corresponding half-shell 51 or 52. This three-way pipe 2 is formed in the upstream end 55 of the enclosure 5.

The two mouths 23 and 24 are coaxial axis Z-Z ' perpendicular to the plane YY' and intersecting the axis X-X ' .

The circular inlet 20 is provided with a filter 25 preventing the passage inside the chamber 5 of suspended particles (in particular limestone), present inside the primary water circuit.

The inlet orifice 20 extends inside the enclosure 5 by a tube 26 for introducing the primary fluid, of cylindrical shape and coaxial with the axis X-X ' of the inner shell 65.

This tube 26 extends from the inlet opening 20 to a short distance from the concave bottom 68, so that the flow of primary liquid entering inside this tube is deflected by the bottom 68 and brought back into position. direction of the upstream end 53 of the enclosure (see arrow J ).

The pipe 10 is fitted and then held in the upstream mouth 23 with a not shown clip, the seal being provided by a seal 101, the pipe 11 is fitted and then held likewise in the mouth 24, sealing being provided by a seal 110.

The pipes 10 and 11 could also be made integral with these upstream mouths 23 and downstream 24 by any other appropriate means ensuring the seal, (threaded connection etc ....).

The three-way manifold 2 is further provided with a baffle lip 27 extending inwardly toward the orifice 20 locally reducing the inside diameter of said conduit. Its function is to direct the jet of primary fluid against the surface of the filter 25, so as to eliminate in heating mode radiators any impurities that would accumulate during the sanitary heating mode.

The three-way valve 7 will now be described with reference to figures 4 , 5 , 8 , 9 , 10 and 11 .

A complementary piece 700 made of plastic, the shape of which appears better on the figure 10 is introduced inside the downstream end 54 of the upper half-shell 52. It has an orifice 70 and an orifice 720 defining the seats of a valve 75. The orifice 70 is the orifice through which the fluid primary comes out of the enclosure 5.

This complementary piece 700 is arranged so that the orifice 70 extends in a vertical plane and the orifice 720 is located in the extension of a conduit 72, integrally molded with the lower half-shell 51 and extending therein along a longitudinal axis T-T ' perpendicular to the Y-Y' plane and intersecting the X-X ' axis.

The conduit 72 opens out of the enclosure 5 at an upstream mouth 73 inside which is fitted and then crimped the pipe 12, the seal being provided by a seal 120.

The pipe 13 is fitted and then crimped into a downstream mouth 74 of axis T-T ' , the seal being provided by a seal 130. This mouth 74 is integral with the upper half-shell 52.

It will be noted that the channel 50 opens out in the vicinity of the mouth 74 via an orifice 550.

The three channels of the valve 7 are therefore constituted by the outlet orifice 70, by a channel opening into the downstream mouth 74 and by a channel opening into the upstream mouth 73.

As it appears better on figures 4 , 5 , 8 , 9 and 11 , a disc valve 75 is mounted eccentrically on a rotary shaft 76 whose axis SS 'is tangent to the valve at a point A.

The S-S ' axis is parallel to the Y-Y' plane and perpendicular to the X-X ' axis.

The shaft 76 is rotated about the axis SS 'by a motor 77 placed outside the enclosure 5, a rotary joint 78 being formed in the wall of the enclosure 5 for the passage of this shaft . The opposite end of the shaft 76 rests in a bearing 760 formed in the complementary part 700.

The valve 75 carries a superior disc-shaped elastic lining 750, able to bear against the edge of the outlet orifice 70, so as to close the latter in a completely sealed manner, the position shown in dashed lines in FIG. figure 4 ) and a lower discoidal resilient lining 751 able to sealingly close the orifice 720, when the shaft 76 is in the position shown in FIGS. figures 4 , 8 , 9 and 11 .

The relief valve 8 and its role will now be described in more detail with reference to the figures 4 and 12 at 14 .

It can happen at certain times of operation of the device that all the valves supplying the radiators are partially or completely closed, especially when they are equipped with thermostatic valves.

The flow rate of the water circulating in the heating circuit is then zero or very low.

In this case, the main exchanger of the boiler is poorly irrigated with water, which can cause overheating and boiling starts, harmful to its operation and its life.

To avoid these problems, it is known to mount a discharge valve or "bypass", between the starting line 10 of the boiler and the lines 13 and 14 back to the boiler.

Such a valve equipped with a calibrated spring, allows the passage of a minimum flow of sufficient primary fluid to avoid boiling phenomena, when the flow rate in the installation of the radiators 100 is insufficient or zero.

According to the invention, this discharge valve 8 is integrated directly into the enclosure 5 of the hot water production device 4.

The valve 8 is mounted on a substantially cylindrical sleeve 56, of axis W-W ' perpendicular to the axis X-X' , integral with the wall of the recess 521.

The valve 8 comprises a fixed part 80, having the shape of a substantially hemispherical dome, axis W-W ' , whose opening is directed downwards.

The piece 80 is retained inside the sleeve 56 by a ring 83 of the circlip type, the assembly being mounted in a sealed manner, by an elastic annular seal 84, interposed between the elements 80 and 56.

At its base, the piece 80 rests in a sealed manner on a discoid base 57, integral with the recess 521.

This disc base 57 is pierced with a central circular orifice 58.

As it appears better on the figure 13 in the vicinity of the orifice 58 is provided a vertical partition 59. It is substantially tangential to the opening 58.

On the other side of the vertical partition 59, with respect to the orifice 58, the discoid portion 57 is traversed by a second oblong opening 570 (see FIG. figure 15 ).

The valve 8 is provided with a piston 85 comprising a circular base 86, substantially discoidal, and an axial rod 87 of axis W-W ' .

The latter is guided in translation, along the axis W-W ' in a tubular sleeve 81 formed in the portion 80 in the form of a dome.

A helical compression spring 82 constantly tends to push the piston 85 downwards.

The base 86 of the piston carries an annular elastic seal 860, adapted to bear against the edge of the orifice 58, so as to seal it completely leaktight, when the piston 85 is in the lower position under the solicitation of the spring 13, as shown in the Figures 12 and 13 .

In the absence of domestic water drawing, in the case where the radiators are closed or partially closed, a significant overpressure develops in the channel 50, called "discharge", which will cause the lifting of the piston 85 to against the thrust of the spring 82. This has the effect of releasing the orifice 58.

In this position illustrated on the figure 14 , the water passes through the orifice 58, penetrates inside the dome 80, leaves this space downwards through the opening 570 and is found on the other side of the partition 59, so that it can flow into the discharge channel 50, through the orifice 550 and the mouth 74 to return to the boiler 1.

The value of the stiffness of the spring 82 is chosen according to the overpressure threshold beyond which it is desirable for the piston 85 to rise.

It is also possible to provide directly on the chamber 5, a filling valve connected to the cold water inlet inlet, and also to provide connectors receiving temperature sensors of the various central heating fluids and domestic hot water (not shown).

The figure 16 is a simplified embodiment of an embodiment in which the chamber 5 is significantly longer than the heat exchanger 6, the length of the tube 26 for introducing the primary fluid being adapted accordingly. This makes it possible to increase the volume of primary hot water present in the vicinity of the heat exchanger 6 and to prevent this primary water from cooling too rapidly when sanitary water is taken and the cold water begins to enter the coil 69.

The figure 24 illustrates an alternative embodiment of the device of the figure 16 in which the tube 26 for introducing the primary fluid is not connected to the upstream mouth 23 but is integral with a vertical partition 522, offset towards the heat exchanger 6 and integral with the enclosure 5. This partition 522 defines with the left half of the enclosure 5 (with respect to the figure 24 ), an additional volume of primary water accumulated in reserve.

The hot water production device 4 is mounted in the mixed central heating and domestic hot water distribution system as shown in FIG. figure 17 .

The operation of the installation is identical to that described in conjunction with the Figures 1 and 2 and the three-way valve 7 makes it possible to select the path of the primary fluid inside the installation. When the primary fluid flows in the direction of the radiators 100, the deflector lip 27 locally increases the speed of this fluid, which makes it possible to eliminate the impurities accumulated on the filter 25, especially when this primary fluid is circulating towards the inside of the fluid. enclosure 5.

Claims (20)

1. Heat exchanger (6) comprising a tube (69) of a material that is a good heat conductor wound in a helix to form a coil in which a "secondary" fluid is intended to circulate, this coil (69) being held between an "internal" cylinder (65) and an "external" cylinder (66) that are coaxial and assembled together at each of their two ends, said coil (69) having a flattened substantially oval cross section the major axis of which is substantially perpendicular to the axis (X-X') of the helix, each turn (62) of the coil (69) having radial faces (620, 621) that are spaced from the radial faces (621, 620) of the adjacent turn (62) by a gap (L) of constant width, a "primary" fluid being intended to circulate between each turn (62) of said coil (69) in contraflow with respect to the circulation of said secondary fluid, characterized in that the gap (L) between two adjacent turns (62) of the coil (69) is defined by at least one helicoidal projecting member (622, 623, 623', 628, 628', 629, 629', 64) with the same pitch as the coil (69) disposed between the facing radial faces (620, 621) of the turns (62) and in that the internal cylinder (65) and the external cylinder (66) are assembled together at each of their two ends by a helicoidal flange (67, 67'), the gap (676, 676') between the ends (674, 675; 674', 675') of the turns of which allows said primary fluid to pass and to circulate between the turns (62) of said coil (69) on either side of said projecting member (622, 623, 623', 628, 628', 629, 629', 64') between said cylinders (65, 66).
2. Heat exchanger according to Claim 1, characterized in that said projecting member (622) is pressed into one of the radial faces (621) of the turns (62) of the coil (69) and comes into contact with the radial face (620) of the facing adjacent turn (62).
3. Heat exchanger according to Claim 1, characterized in that at least one projecting member (623, 628, 629) is pressed into one radial face (621) of the turns (62) and in that an identical number of projecting members (623', 628', 629') is pressed into the other radial face (620) of the turn, each projecting member (623, 628, 629) of one radial face (621) coming into contact with a projecting member (623', 628', 629') of the facing radial face (620).
4. Heat exchanger according to Claim 3, characterized in that a first pair of semicylindrical projections (628, 629) is pressed into one of the radial faces (621) of the turns (62) and in that a second pair of semicylindrical projections (628', 629') is pressed into the other radial face (620) of said turns, each projection (628, 629) of one of the radial faces (621) coming into contact with a projection (628', 629') of the facing radial face (620).
5. Heat exchanger according to Claim 1, characterized in that said projecting member is a helicoidal rigid wire (64) mounted so that each of its turns (640) is interleaved between two adjacent turns (62) of the coil (69).
6. Heat exchanger according to any of the preceding claims, characterized in that the opposite shorter sides (624, 625) of each turn (62) of the coil (69) are brazed to the internal cylinder (65) and the external cylinder (66) at their respective points of contact (626, 627) with the latter.
7. Device for the production of domestic hot water (4), characterized in that it comprises an enclosure (5) inside which is installed a heat exchanger (6) according to any of Claims 1 to 6, the water to be heated constituting the secondary fluid that circulates inside the coil (69), each end (60, 61) of this coil (69) passing through the wall of said enclosure (5) at a port (510, 511) provided for this purpose, primary fluid entry into and exit from the interior of the enclosure (5) being respectively effected via an inlet orifice (20) and an outlet orifice (70).
8. Device according to Claim 7, characterized in that a primary fluid distribution chamber (680) is provided inside said enclosure (5), said chamber (680) being delimited by the interior wall of the internal cylinder (65) and by a circular bottom (68) closing and sealing the end of said internal cylinder (65) situated in the vicinity of the secondary fluid inlet orifice (60), referred to as the "inlet end", and in that a primary fluid introduction tube (26) is disposed inside said internal cylinder (65), one of its ends being connected to the primary fluid inlet orifice (20) and its opposite end discharging at a short distance from said bottom (68) so that the latter forms a deflector that redirects the inflow of primary fluid in the direction of the opposite end of said distribution chamber (680).
9. Device according to Claim 8, characterized in that said bottom (68) is concave, its concave side facing toward the primary fluid introduction tube (26).
10. Device according to any of Claims 7 to 9, characterized in that it comprises a three-channel tube (2) integrated with said enclosure (5), one channel of which constitutes the primary fluid inlet orifice (20), another an upstream port (23) and the third a downstream port (24), said inlet orifice (20) being provided with a filter.
11. Device according to Claim 10, characterized in that said three-channel tube (2) is provided internally in the vicinity of the inlet orifice (20) with a deflector lip (27) for directing the inflow of primary fluid in the direction of said inlet orifice (20).
12. Device according to any of Claims 7 to 11, characterized in that it comprises a three-channel primary fluid distribution valve (7) integrated into said enclosure (5), one channel of which consists of a primary fluid outlet orifice (70), another channel of which discharges into a downstream port (74) and the third channel of which discharges into an upstream port (73), these two ports (73, 74) being provided in the wall of the enclosure (5), and this valve (7) including a valve closure member (75) adapted to block selectively either said outlet orifice (70) or the channel discharging into the upstream port (73).
13. Device according to Claim 12, characterized in that said valve closure member (75) is mounted on a shaft (76) driven in rotation by a motor (77).
14. Device according to any of Claims 7 to 13, characterized in that a discharge channel (50) is provided inside the enclosure (5) to establish fluid communication between the primary fluid inlet (20) and the primary fluid outlet (70), this discharge channel (50) being equipped with a discharge valve (8).
15. Device according to Claims 12 and 14, characterized in that the discharge channel (50) is provided between a depressed portion (521) of the enclosure (5) and an intermediate partition (55) disposed between said depressed portion (521) and the external cylinder (66), this discharge channel (50) extending from the vicinity of the upstream end (53) of the enclosure as far as its downstream end (54), where it discharges into the downstream port (74) of the three-channel valve (7).
16. Device according to Claim 14 or 15, characterized in that said discharge valve (8) comprises a piston (85) spring-loaded by a calibrated spring (82) and adapted to close a primary fluid passage orifice (58) provided in said discharge channel (50) if the pressure of said primary fluid reaching the interior of the enclosure (5) is below a predetermined threshold value and to open this passage if the pressure exceeds that value.
17. Device according to Claim 16, characterized in that said discharge valve (8) is mounted in a sleeve (56) fastened to the depressed portion (521) of the enclosure (5) and the axis (W-W') of which is perpendicular to the plane of the depressed portion, the piston (85) being mobile in translation along said axis (W-W') of the sleeve (56) and being spring-loaded by a compression coil spring (82) that bears against a dome-shape part (80) fixed and sealed to said sleeve (56).
18. Device according to Claims 14, 15, 16 and 17, characterized in that said discharge valve (8) comprises a fixed transverse partition (59) dividing the space between said depressed portion (521) of the enclosure (5) and the intermediate partition (55) and a base (57) fastened to this fixed partition (59) through which passes on one side the orifice (58) that may be blocked by said piston (85) and on the other side an opening (570) that communicates at all times with the interior of the dome-shaped part (80).
19. Device according to any of Claims 7 to 18, characterized in that the enclosure (5) is made of plastic material.
20. Mixed domestic hot water distribution installation comprising a central heating primary circuit (I) and a domestic hot water secondary circuit (II), characterized in that it is equipped with a device (4) according to any of Claims 7 to 19 for producing domestic hot water connected in parallel with the radiators (100) of the central heating circuit, the central heating water supplied by a boiler (1) constituting said primary fluid and the domestic hot water constituting said secondary fluid.

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