EP2681499A1

EP2681499A1 - Heat exchanger for heating boilers

Info

Publication number: EP2681499A1
Application number: EP12714070.5A
Authority: EP
Inventors: Daniele Bresti
Original assignee: CUBO D Srl
Current assignee: CUBO D Srl
Priority date: 2011-03-03
Filing date: 2012-03-02
Publication date: 2014-01-08
Also published as: CA2828912A1; US20140014306A1; WO2012117432A1; EA201300983A1

Abstract

The invention relates to a heat exchanger of the fumes-water type configured to couple with a burner for the manufacture of boilers for domestic or industrial use. The heat exchanger is essentially constituted of an exchanging body (2) made of die-cast aluminium with two half-shells (2a and 2b), to be mounted in a mutually opposing fashion, and enclosed within a casing (3), made of a plastic or aluminium material, formed of two half-parts (3 a and 3b) to couple in order to contain therewithin the exchanging body (2), thus constituting two seats, one internal one for the flow of fumes and the other, external, one for the flow of water, which runs upwards from the bottom, passing all around the exchanging body (2) with a mixed route (partly parallel and partly spiral). The exchanger in question is of the "cross flow" type, i.e. the input on the water side corresponds with the heat exchanger fumes output and allows high heat exchange performance.

Description

HEAT EXCHANGER FOR HEATING BOILERS.

TECHNICAL FIELD

The present invention relates to a heat exchanger to couple to a burner, for the manufacture of boilers for domestic use, to form an innovative heating system.

At present, boilers have quite considerable overall dimensions due to the presence, between the various components, of heat exchangers which, due to their conformation, occupy considerable space, as well as being not particularly efficient. As is known, a heat exchanger is any device intended to transfer heat between fluids separated by a conductive wall, wherein the heat is transmitted, through the wall, from the warmer fluid to the colder one.

Nowadays, the exchangers available on the market which are present in condensing boilers for heating and hot water production come in two types: stainless steel extruded tubular exchangers and cast aluminium exchangers. The first of these is, at present, the most widespread, despite being more recent. In this case, rather than exchanger the term "module" is more appropriate because, in addition to the exchanging system, the said "module" also comprises the premixed burner-blower system and all the part linked to the discharge of fumes. The diffusion of this system has led to a standardisation of the technology for condensing boilers, which seem to come from the same production source.

In more detail, in a boiler, at present, the exchanger consists of a tube that runs in a serpentine fashion or different tubes placed above a burner, used to heat the air that will come into contact with the metal surface intended to remove the heat from the air and transfer it to the water present inside the tubes. The tubes are connected to a cold water supply pipe and an output pipe for the hot water which, during the passage inside the tubes of the exchanger, heats up. The second type of exchanger available on the market is that obtained by casting, which features much thicker component parts due to construction needs, since the moulds which produce them, during casting, are filled by gravity casting.

Consequently, current heat exchangers weigh considerable amounts due to the very system by which they are manufactured. Furthermore, exchangers must undergo further processing for cleaning and finishing, which affects production costs.

In addition, it has been noticed that the material which makes up the heat exchanger and which is obtained by casting may have bubbles, cracks, porosity, imperfections and/or micro-fissures which, over time, lead to wear of the material with breakage of the heat exchanger, cracks in the walls and reduced operating capacity due to losses caused by less efficient heat exchange between the parts.

Furthermore, during the production process, the casting involves the use of acids which emit fumes that are harmful both to workers' health and the environment, with a consequent increase in pollution.

The aforesaid heaters available on the market, as mentioned earlier, while performing their task, nevertheless, present various drawbacks.

In addition to the above, present-day condensing boilers reduce the emission of very hot fumes but, in comparison with conventional boilers, are very elaborate, complicated, and delicate devices which are costly both to produce and to maintain and have rather high consumption levels, as they also have areas of heat dispersion.

Furthermore, nowadays, houses are increasingly small and offer ever less space, therefore there is a great need felt for boilers with smaller overall dimensions and more accessible costs.

Another need is for boilers with an optimum output and contained consumption so that heating costs do not affect family budgets greatly. Finally, the majority of boilers available on the market have, within their structure, an insulating material which is very fragile and scarcely resistant to humidity, with the result that, over time, it wears and loses effectiveness, making the boiler more dispersive and therefore more onerous in terms of consumption and even less efficient. Furthermore, the management of the thermal insulating material by the boiler manufacturers involves various complications which are inconvenient because of the delicacy of the material and triggers problems linked to storage of the material and the finished boilers, apart from the fact that, at the end of the boiler's life, the production residues and the resulting material must be disposed of and are highly polluting materials.

The aim of the present invention is essentially to resolve the problems of the commonly known technique, overcoming the aforesaid drawbacks by means of a heat exchanger able to fully exploit all the heat produced by a burner to heat up a fluid, in one passage only and without the recovery of fumes and to allow the passage of heat through a notably increased exchange surface area.

A second aim of the present invention is to have a heat exchanger able to prevent heat losses and dispersion and offer notable wear resistance.

A third aim of the present invention is to have a heat exchanger obtainable by die- casting, in a simple way, which offers considerable resistance, a material whose structure offers better wear-resistance characteristics and better compactness, without porosity, inclusions, gas bubbles, cracks or micro-fissures, so as to obtain very high heat transfer coefficients.

Another aim of the present invention is to have a heat exchanger which has a structure wherein the constituent material is obtained with a low melting alloy (which requires less energy to melt), so as to allow containment of production costs. A further aim of the present invention is to have a heat exchanger which allows savings in economic and energy terms in the management of the heating system, with savings in terms of burner energy consumption and the same flow of heated liquid and the same temperature obtained.

A further aim of the present invention is to have a heat exchanger which has a simple, modular structure and smaller overall dimensions, so as to have more compact boilers. A further but not final aim of the present invention is to produce a heat exchanger which is easy to manufacture and works well.

These aims and others besides, which will better emerge over the course of the present description, are essentially achieved by means of a heat exchanger, as outlined in the claims below.

Further characteristics and advantages will better emerge in the detailed description of a heat exchanger according to the present invention, provided in the form of a non- limiting example, with reference to the accompanying drawings, in which:

- Figure 1 shows, schematically and from a perspective view, a heat exchanger according to the present invention;

Figure 2 shows, schematically, an exploded view of the heat exchanger in Figure l ;

Figure 3 shows, schematically and from a different perspective, the exchanger in Figure 2;

Figure 4 shows a schematic view of the route followed by the water in the exchanger according to the present invention.

Figure 5 shows a variant of the exchanger in Figure 1 ;

- Figure 6 shows a perspective view of a component of the exchanger in Figure 1 ; - Figure 6A shows a detail of the component in Figure 6; Figure 7 shows a perspective view of the other part of the component in Figure 6;

Figure 7 A shows a detail of the component in Figure 7;

Figure 8 shows a perspective view of a part of a second component of the exchanger in Figure 1 ;

Figure 8 A shows a detail of the component in Figure 8;

Figure 9 shows a perspective view of the other part of the second component in Figure 8;

Figure 9 A shows a detail of the component in Figure 9;

Figure 10 shows a perspective view of a variant of the second component of the exchanger in Figure 1 ;

- Figure 11 shows a perspective view of the other part of the variant of the second component in Figure 10;

Figure 12 shows, schematically and from a perspective view, a second embodiment of the heat exchanger according to the present invention;

- Figure 13 shows, schematically, an exploded view of the heat exchanger in Figure 12;

- Figure 14 shows a schematic view of the route followed by the water in the exchanger in Figure 12.

Figure 15 shows a variant of the exchanger in Figure 12;

- Figure 16 shows a perspective view of a part of the component of the exchanger in Figure 12;

Figure 16A shows a detail of the component in Figure 16;

- Figure 17 shows a perspective view of the other part of the component in Figure Figure 17A shows a detail of the component in Figure 17;

Figure 18 shows, schematically and from a perspective view, a third embodiment of the heat exchanger according to the present invention;

Figure 19 shows, schematically, an exploded view of the heat exchanger in Figure 18;

Figure 20 shows, schematically and from a different perspective, the heat exchanger in Figure 18;

Figure 21 shows a schematic view of the route followed by the water in the exchanger in Figure 18.

- Figure 22 shows a variant of the exchanger in Figure 18;

Figure 23 shows a perspective view of a part of the component of the exchanger in Figure 18;

Figure 23 A shows a detail of the component in Figure 18;

Figure 24 shows a perspective view of the other part of the component in Figure 1 8;

Figure 24A shows a detail of the component in Figure 18;

With reference to the figures, 1 denotes, as a whole, a heat exchanger according to the present invention.

The heat exchanger 1 shown in Figures 1 to 7 has a mixed route for the water, which is partly parallel and partly spiral in form, while the exchanger shown in Figures 12 to 17 has a parallel water route, and the one shown in Figures 18 to 24 has a spiral water route.

The heat exchanger 1 is of the aluminium finned fumes-water type obtained by die- casting and configured to couple with a burner for the manufacture of boilers for domestic or industrial use. The heat exchanger 1 according to the present invention is essentially constituted of an exchanging body 2 composed of two half-shells 2a and 2b, to be mounted in a mutually opposing fashion, and enclosed within a casing 3 formed of two half-parts to couple in order to contain therewithin the exchanging body 2, thus constituting two seats, one internal one for the flow of fumes and the other, external, one for the flow of water, as shown in Figures 1, 3, or 12 or 18 and 20.

In more detail, and as shown in Figures 10 and 1 1, each half-shell 2a and 2b has a structure 20 composed of an essentially U-shaped element containing, therewithin, a plurality of fins 21, arranged in a reciprocally parallel fashion and parallel to the sides of the U.

Furthermore, each fin 21 has a configuration with a trapezoidal profile in which the larger base is in contact with the base of the U and the smaller base is free, the side corresponding to the height of the trapezoid is perpendicular to the base of the U and is positioned at the bottom, while the remaining side is positioned on the top, towards the centre of the half-shell.

In particular, the profile of each fin 21 is smooth and has a slightly triangular section, as shown in Figure 11. Furthermore, each fin 21 may have cuts 21a which subdivide it into different areas for a better heat transmission to the U-shaped element.

The height of each fin 21 is almost double the height of the sides of the U, as can be seen in Figure 1 1.

In particular, each free end of the sides of the U-shaped element has a chamfer 26, which creates a space envisaged to be occupied by welding filler when the two half- shells are brought together and mutually joined to form the exchanging body 2 of the exchanger.

With the configuration as described hereabove, when the two half-shells are coupled together, the fins on the first half-shell fit into the space present between the fins on the second half-shell, creating a small V-shaped chamber, as shown in Figures 1, 2 or 12, 13 or 18, 19.

In particular, the first and the last fin are appropriately positioned so as to have a space for the insertion of the corresponding fin on the other half-shell, so as to assemble the entire exchanging body with two facing half-shells, as shown in Figure 3 or 20.

By mounting the two half-shells in a mutually opposing fashion, the fins penetrate the spaces available between the reciprocally opposing fins and by varying the distance between the two half-shells a gap is obtained that allows a constant fume speed to be reached, following a processing and assembly technique that determines an angle between the two half-shells.

This configuration of the two half-shells allows a net area for the passage of the fumes which varies from the input to the output, i.e. higher at the input and lower at the output, allowing a constant fume speed even as the temperature decreases, which is beneficial for the performance of the exchanger.

According to the present embodiment and as shown in Figures 3 and 20, externally to the U-shaped element, there is a plurality of blades 22 which come out in a perpendicular fashion and which are positioned mutually parallel and parallel to the base of the U-shaped element and perpendicular to the fins 21.

One variant envisages that the blades in the upper part are greater in number so as to obtain an increase in the exchange surface in that section and are fewer in the central part and decrease further in the lower part.

Also externally to the U-shaped element, a plurality of small grooves 27 is envisaged, arranged in parallel and alternating with the blades 22, whose function will be explained later. In addition to the above, in one of the two half-shells, at the top, two or more seats 28 are envisaged to accommodate an ignition device, along with one or more control sensors of a commonly known type. Furthermore, each U-shaped element may be slightly larger in the upper part than in the lower part.

Beneath the U-shaped element, as shown in Figures 8 and 9, there is an element 25 which creates a seat and a space for the collection of condensate. It is triangular in shape and comprises a discharge pipe 25a and an opening 25b for the discharge of the fumes which have flowed through the interior of the two half-shells.

The element 25 is envisaged for the collection of the condensate produced in the internal seat where the fumes flow through, conveying the said condensate towards the condensate discharge pipe 25a and conveying the exhausted fumes to an expulsion pipe, which is the opening 25b. In accordance with the present embodiment, the two half- shells 2a and 2b of the exchanging body are enclosed by the casing 3 made of a plastic or aluminium material. The casing 3 is composed of two half-parts 3a and 3b which are mutually coupled so as to enclose the exchanging body, as shown in Figures 1, 2 or 12, 13 or 18, 19.

Each half-part of the casing is substantially constituted of a C-shaped element inside which there are a series of dividers which have different conformations.

In accordance with the present invention, a half-part 3 a of the casing envisages that the dividers 31 are arranged in a mutually parallel fashion and spaced at slightly decreasing intervals in an upwards fashion and as shown in Figure 23, while in the other half-part, 3b they are also mutually parallel and spaced at decreasing intervals in an upwards fashion but have a conformation which envisages a first section 32 arranged in a horizontal L shape, located partly on the side of the C and partly on the wall, a second section 33 arranged diagonally upwards, and a third section 34 which is once again horizontal and located on the other side of the symmetrical C to section 32, as clearly shown in Figure 24.

One variant shown in Figures 16 and 17, envisages that the half-part 3 a of the casing comprises a series of dividers 31 having a C-shaped profile, broken up by dividers 31a which have a central break. In particular, the dividers 31 are envisaged with a small vertical wall 38 positioned centrally and perpendicular to each divider 31, as clearly shown in Figure 16.

Both the dividers 31 and 31a are arranged in a mutually parallel fashion and spaced apart at slightly decreasing intervals in an upwards fashion and also as shown in Figure 16, while in the other half-part 3b, they are also mutually parallel and spaced apart at decreasing intervals in a upwards manner, as shown in Figure 17. There are also dividers 31 and 31a in the half-part 3b similar to those in the half-part 3 a, which are spaced apart but between the two half-parts, the dividers 31 and similarly the dividers 3 la are mutually staggered by one level, as is clearly visible when comparing Figures 16 and 17.

A different embodiment envisages that, as shown in Figure 6, the half-part 3a of the casing is provided with a first divider 31 , positioned at the bottom, having a C-shaped profile and provided with a small vertical wall 38 positioned centrally and perpendicular to a divider 31a which has a central break and a series of dividers 31 having a C-shaped profile. All the dividers present are arranged in a mutually parallel fashion and are spaced apart at slightly decreasing intervals in an upwards fashion and also as shown in Figure 6, while in the other half-part 3b, they are also mutually parallel and spaced apart at decreasing intervals in an upwards fashion but have a conformation which envisages the presence of a first divider 31 with C-profile, a second divider 31c having a C-shaped profile and envisaged with a small vertical wall 38 positioned centrally and in a perpendicular fashion, followed by a divider 31a composed of a horizontal L-shaped section, located partly on the side of C and partly on the wall, and a subsequent series of dividers having a conformation that includes a first horizontal section 32, located on the side of the C, like the divider 31a, a second section 33 arranged diagonally upwards and a third section 34, which is once again horizontal and located on the other side of the symmetrical C and parallel to the divider 31 a, with a last divider 3 Id which envisages a first horizontal section 32 and disposed on the side of the C, like the divider 31a, and a second section 33 arranged diagonally upwards, as clearly shown in Figure 7.

At the free end of each divider in each half-part 3a and 3b there is a projection 35 envisaged to fit into a groove 27 present on the outer wall of the U-shaped element and which is placed between the blades 22 so as to create a route along which the water is forced to flow with a spiral shape that runs from the bottom upwards in the first case, or in the second case, such route has a conformation with parallel levels which make the water run upwards on the side of the C to the top level and then run along a trajectory which is parallel in each half-part of the casing and which meets on each side of the casing as shown in Figure 14, then runs up to the top level, so that it is running from the bottom upwards, while in the third, it has a mixed conformation.

In more detail, in the mixed conformation the route the water takes is initially along parallel levels, which make the water run up the side of the C to the top level and the water runs along a trajectory which is parallel in each half-part of the casing and which meets up on each side of the casing, as shown in Figure 4, and then continues to run up to the upper levels in a spiral, so as to bring water from the bottom upwards.

The distribution of the dividers, which are coupled to the exchanging body through the ribbing 35 and the grooves 27, as previously described, allows a route to be obtained for the water which runs from the bottom upwards during its heating route, passing all the way around the exchanging body 2.

In addition to the above, the half-part 3b of the casing has two connectors on the side of the C, one being a lower one 40 and the other an upper one 41, wherein the cold water enters via the lower one, and the hot water leaves via the upper one. The connectors 40 and 41 are preferably positioned on the opposite side to the fumes outlet, but not necessarily.

The two half-parts of the casing are arranged to mutually couple and also to couple with the exchanging body 2; in fact, the casing projections 35 enter the grooves 27 in the exchanging body and, once the two half-parts of the casing are coupled to the exchanging body, these are further mutually constrained by one or more weld spots and, then, on the top, the burner is positioned on the U-shaped element.

When the two half-shells are mutually assembled and likewise for the two half-parts of the casing, a channel is obtained therebetween for the water route. The water entering from the connector 40 at the bottom runs along an ascending spiral route in the first case, a parallel ascending route in the second case and a mixed ascending route (part parallel and part spiral), in the third case.

In more detail, in the parallel route, the cold water entering from the lower connector 40 on the casing splits into two parallel flows which reach the opposite side of the casing, meet up and run up to the level above, then they split up a second time and each one performs the route backwards until reaching a point corresponding with the entrance, but on the level above. The two flows meet again during the ascent to the third level, they mix so as to render uniform the temperature (in the event that one part of the water is warmer than the other), and likewise the speed and pressure.

Running to the level above, the water splits again into two flows and repeats the same route as at the beginning and carries on in this way until it reaches the outlet connector. In the mixed route, meanwhile, the cold water entering from the lower connector 40 on the casing splits into two parallel flows which reach the opposite side of the casing, meet up and run up to the level above, then they split up a second time and each one performs the route backwards until it reaches a point corresponding with the entrance, but on the level above. The two flows meet again during the ascent to the third level and - as in the previous case - they mix so as to render the temperature, speed, and pressure uniform, and continue as a single flow along a spiral route until the outlet connector is reached.

One variant envisages the parallel route running over several levels with the spiral route reduced.

In accordance with the present embodiment, the fins 21 are envisaged to absorb the heat produced by the burner positioned on top of the exchanging body and transmit it to the U-shaped element.

The internal seat of the heat exchanger is envisaged for the passage of hot fumes while the external route is envisaged for the passage of water.

This configuration allows the automatic reduction of heat dispersion towards the outside since the inner seat is dedicated to the passage of the fumes and the external route to the passage of water to be heated.

Furthermore, the water route envisages that the channel obtained is larger at the bottom in order to contain a greater quantity of cold water returning from the system, so as to better cool the fumes.

The U-shaped element, in the upper part thereof, can be varied in shape and size in order to adapt the exchanger to the structure of existing boilers, modifying the couplings and connections for the burners used. According to the present invention, the heat exchange takes place as follows: from the top downwards for the flow of combustion gases and from the bottom upwards for the flow of water.

The exchanger in question is of the "cross flow" type, i.e. the input on the water side corresponds with the heat exchanger fumes output, thus allowing, with this configuration, high heat exchange performance because the low water temperature guarantees a sufficient level of condensation of combustion fumes, which are also at a low temperature. Due to the conformation adopted, the fumes are forced to flow along a route, from top to bottom, and are subsequently conveyed to the boiler's fumes discharge system, while the water flows in the opposite direction, from the bottom up (guaranteed by a special circulation pump outside the burner). The route that the water takes, also on the side of the exchanging body, prevents heat loss as the water surrounds the entire exchanging body.

The water route created outside the exchanging body allows an exchanger to be obtained in which the chamber containing the hot fumes is completely enclosed and surrounded externally by the water to be heated, as shown in Figure 4, 14 or 21.

This allows a significant minimisation of heat loss towards the outside as there are no areas/surfaces where the hot fumes can dissipate the heat directly to the outside of the heat exchanger.

The exchanger is preferably made of aluminium or special aluminium alloys in order to resist corrosion, have high thermal conductivity and be die-castable. More in detail, the alloys used are of the low melting type which require a smaller amount of energy to reach melting point fusion with consequent energy saving which translates into a containment of production costs, as well as a reduction in the pollution caused during the production and an elimination of noxious fumes since acids are not used in the moulds, as happens in the production of cast exchangers.

In fact, when the half-shell is die-cast, it acquires a considerable resistance to wear and corrosion since there are no bubbles, cracks, or other imperfections within the material, as compared to those which are sand-cast, although the thicknesses of both the structure of the exchanging body and the fins are very low.

The exchanger in question does not have seals, therefore there is no longer a risk of leakage. Furthermore, the two half-shells of the exchanging body and the two half-parts of the casing, as previously described, are mutually welded and this operation is done in a fully automated way, with consequent savings in processing times and, consequently, in production costs. Finally, it is much lighter than existing exchangers.

In accordance with the present invention, the entire exchanging body is very simple as it is obtained by assembling the two half-shells and, likewise, the casing is also obtained by assembling two half-parts, as shown in Figure 3 or 20.

In particular, the exchanger in question with the configuration as described, allows exploitation of the heat in the first few centimetres, since the discharge of the highest temperature occurs mainly in the first section of the exchanging body and is less in the remainder than in exchangers according to the commonly known technique, which increasingly tend to be widened to enhance performance.

In this way, the heat exchanger can have very contained dimensions, which means ease of production, with savings in materials and therefore in costs.

With the exchanger in question, the distribution of the heat absorbed has improved and, consequently, the ratio of heat absorbed and heat released has changed, unlike in the commonly known technique, wherein - until now - the only consideration had been to improve absorption and not, as in this case, distribution. The exchanger in question allows the problem of inactive flow to be eliminated since the heat distribution system has been improved.

After the predominantly structural description above, the operation of the invention in question will now be outlined.

The operating principle of the exchanger in question is obtained from the fact that the burner produces heat which heats up the fumes present, which flow downwards, emanating a quantity of heat which is yielded, along the route downwards and towards the boiler discharge pipe, to the spiral, or parallel or mixed route (wherein part is parallel and part is spiral) outside the exchanging body where the water runs, which receives the heat from the fins and from the U-shaped element, which have taken it from the fumes. The fumes make their way from the burner to the discharge pipe, yielding all their heat and using up all the heating energy which has been acquired from the fins all the way along the vertical route taken by the fumes, not just for a short distance as occurs in the commonly known technique.

In the case of a boiler, the water which must be heated enters the exchanger structure, reaching the, respectively, spiral, parallel, or mixed route through a delivery pipe present in the casing, at the bottom, and then leaves hot via the outlet pipe located at the top. As shown in Figure 4 or 14 or 21, during its ascent route, the water takes up all the heat produced by the burner, fully exploiting it, and the fumes that leave via the boiler discharge pipe have burnt up all the calories they had and have a low temperature. The heating process can be continued without interruptions or downtime, and without dispersion of heat or the need to recover heat in order to return it to the interior of the exchanger, as occurs in many boilers according to the commonly known technique. In particular, the configuration of the exchanger allows the use, and therefore the full exploitation, of all the heat produced by the burner to heat up a fluid, in one passage only and without the recovery of fumes.

Thus the present invention achieves the aims set.

The heat exchanger according to the present invention allows a cost-effectiveness of the product linked to the dimensions, weight and material of which it is composed, a cost- effectiveness of the production process as the production process envisaged leads to a higher production speed and rationality than occurs in the commonly known technique, and to a cost-effectiveness of the management as a simpler product can be managed by the manufacturer of the boiler quickly, thus saving on assembly time.

An advantage highlighted by the exchanger in question stems from its simple structure, which leads to the advantages listed above, unlike the modules for the condensing boilers available on the market at present, which are very complex and therefore delicate, whether made of aluminium or steel.

A further aim of the present invention stems from the fact that the exchanger in question allows full exploitation of all the heat produced by a burner to heat up a fluid, in one passage only and without the recovery of fumes and allows the passage of heat through a notably increased exchange surface area.

Furthermore, the exchanger prevents heat loss and dispersion, offers notable wear- resistance, has considerable sealing characteristics and a material structure with improved stress-resistance characteristics due to the better compactness of the material, which is without porosity, inclusions, gas bubbles, cracks or micro-fissures, so as to obtain very high heat transfer coefficients.

In addition, the exchanger according to the present invention allows margins for customisation of the boiler by the manufacturer, unlike as currently occurs with the exchangers according to the currently known technique, which are practically modules that are pre-assembled by the supplier and do not leave the boiler manufacturer any margin for variation.

A further advantage that has emerged with the exchanger according to the present invention is the absence of use of insulating material. In fact, the management of the thermal insulating material by boiler manufacturers involves a series of inconvenient complications, as the insulating material is very fragile and scarcely resistant to humidity, and has an impact on the environment when it has to be disposed of.

A further advantage stems from the extremely contained dimensions; in fact, the compactness of the system offers diverse embodiment solutions through the combination of different internal boiler layouts. In particular, the shallow depth of the exchanger facilitates the possibility of building condensing boilers with reduced dimensions and which can be built-in, as well as having reduced power.

A further advantage is found by obtaining the half-shell directly from a die, with consequent savings on all the subsequent costly mechanical or assembly processing which must be carried out on the components of cast exchangers, with a reduction in the weight of the exchanger which means consequent notable savings in production costs. With the heat exchanger according to the present invention and the same effective area of passage on the fumes side, exchangers can be created with high heat exchange surfaces towards the water flow sections. This is due to the fact that the central channel along which the fumes flow is completely surrounded by the water route and therefore this translates into the heat exchanger's ability to transfer the heat from the fumes to the water, a condition which makes it possible to obtain exchangers with high performance and compact dimensions.

In fact, the configuration of the exchanger with the external upwards water route allows all the heat produced by the burner to be used in the route from the top downwards. In this way, the fins are able to absorb all the heat produced and transmit it to the water which runs along the external route.

Advantageously, the heat exchanger allows notable savings in terms of burner energy consumption with the same flow of heated liquid and the same temperature obtained, with consequent savings in the consumption of methane or gas due to the fact that all the heat produced is used and transferred to the water.

Furthermore, the reduced consumption of the burner allows, as a consequence, emissions in the atmosphere to be reduced, with the consequent containment and diminution of pollutants released into the air.

Advantageously, the heat exchanger is simple and modular, features contained overall dimensions and takes advantage of the unused space found in boilers according to the commonly known technique.

In addition to the above, the structure of the exchanger according to the present invention is simple since it is the sum of a few pieces, i.e. two half-shells for the exchanging body and two half-parts for the casing, unlike the components composing the exchangers according to the commonly known technique, which are composed of a number of reciprocally different individual pieces which are then assembled.

A further but not final advantage of the present invention is that it proves remarkably easy to use and to manufacture and works well.

Naturally, further modifications or variants may be applied to the present invention while remaining within the scope of the invention that characterises it.

Claims

A fumes-water type heat exchanger configured to be coupled to a burner for the production of boilers for domestic or industrial use characterised by the fact that the said exchanger is comprised essentially of an exchanging body (2) made of die-cast aluminium with two half-shells (2a and 2b) to be mounted mutually opposite and sealed by a casing (3) made of plastic or aluminium formed of two half-parts (3a and 3b) to be coupled to contain the exchanging body (2) therewithin so as to constitute two seats, one inside for the flow of fumes and the other outside for the flow of water.

A heat exchanger according to claim 1 , characterised by the fact that each half- shell (2a and 2b) has a structure (20) composed of an essentially U-shaped element inside which there is a plurality of fins (21) arranged in a reciprocally parallel fashion and parallel to the sides of the U and outside the U-shaped element, there is a plurality of blades (22) coming out in a perpendicular fashion and which are reciprocally parallel and parallel to the base of the U and perpendicular to the fins (21) and a series of small grooves (27) arranged in a reciprocally parallel fashion and alternating with the blades (22), when the said two half-shells are mutually coupled, the fins of the first half-shell fit into the space between the fins of the second half-shell, creating a small V-shaped chamber and the first and last fins are opportunely positioned so as to have a space for the corresponding fin of the other half-shell to fit in, in order to assemble the entire exchanging body with two facing half-shells.

A heat exchanger according to claim 1 , characterised by the fact that each half- part (3 a and 3b) of the casing is substantially constituted of a C-shaped element inside which there is a series of dividers (31) also with a C-shaped conformation and which are arranged reciprocally parallel and spaced at slightly decreasing intervals in an upwards fashion while in the other half-part (3b) they are always reciprocally parallel and spaced at decreasing intervals in an upwards fashion, but have a conformation which envisages a first horizontal section (32) in an L shape located partly on the side of the C and partly on the wall, a second diagonal section (33) positioned upwards and a third section (34) which is horizontal again and positioned on the other side of the symmetrical C to the section (32) and at the free end of each divider (31) there is a projection (35) envisaged to fit into a groove (27) present on the external wall of the U-shaped element so as to create a route along which the water is forced to flow, with a spiral-shaped conformation, running from the bottom upwards and passing all around the exchanging body (2).

4. A heat exchanger according to claim 1, characterised by the fact that each half- part (3 a and 3b) of the casing is substantially constituted of a C-shaped element in which there is a series of dividers (31) alternating with the dividers (31a) where the dividers (31) have a C-shaped conformation and are endowed with a small vertical wall (38) positioned centrally and in a perpendicular fashion to each of the said dividers, while the said dividers (31 a) have a break at the centre and in the half-part (3 a) the dividers (31 and 31a) are arranged reciprocally parallel and spaced at slightly decreasing intervals in an upwards fashion while in the other half-part (3b) they are also reciprocally parallel and spaced at decreasing intervals in an upwards fashion, but between the two half-parts, the dividers (31) and, similarly, the dividers (31a) are reciprocally staggered by one level.

5. A heat exchanger according to claim 4, characterised by the fact that, at the free end of each divider (31 and 31a) of each half-part (3 a and 3b) of the casing, there is a projection (35) envisaged to fit into a groove (27) present on the outer wall of the U-shaped element of the exchanging body (2) so as to create a route along which the water is forced to flow, the conformation of which features parallel levels which make the water flow up on the side of the C to the top level and thus make the water run along a trajectory that is parallel in each half-part of the casing and which meets on each side of the casing, and then flows up to the top level, thereby flowing from the bottom upwards and passing around the exchanging body (2).

6. A heat exchanger according to claim 1, characterised by the fact that each half- part (3 a and 3b) of the casing is substantially constituted of a C-shaped element inside which there is a series of dividers which have different conformations in which the half-part (3a) of the casing is endowed with a first divider (31), located at the bottom, with a C-shaped profile and endowed with a small vertical wall (38) positioned centrally and in a perpendicular fashion, followed by a divider (31a) with a break at the centre, and by a series of dividers (31) with a C-shaped profile and the half-part (3b) envisages the presence of a first divider (31) with a C-shaped profile, a second divider (31c) with a C-shaped profile and endowed with a small vertical wall (38) positioned centrally and in a perpendicular fashion, followed by a divider (31a) composed of a horizontal section in an L shape positioned partly on the side of C and partly on the wall, and a series of consecutive dividers with a conformation that envisages a first horizontal section (32) which is positioned on the side of the C, like the divider (31a), a second diagonal section (33) positioned upwards and a third section (34) which is horizontal again and positioned on the other side of the symmetrical C and parallel to the divider (31a), with a last divider (3 Id) which envisages a first horizontal section (32) positioned on the side of the C, like the divider (31a) and a second diagonal section (33) positioned upwards.

7. A heat exchanger according to claim 6, characterised by the fact that in each half-part (3 a and 3b) all the dividers are arranged in a reciprocally parallel fashion and are spaced apart at slightly decreasing intervals in an upwards fashion.

8. A heat exchanger according to claim 6, characterised by the fact that, at the free end of each divider of each half-part (3 a and 3b) of the casing, there is a projection (35) envisaged to fit into a groove (27) present on the outer wall of the U-shaped element of the exchanging body (2) so as to create a route along which the water is forced to flow, the conformation of which initially features parallel levels which make the water flow up on the side of the C to the top level and the water runs along a trajectory that is parallel in each half-part of the casing and which meets on each side of the casing, and then continues flowing up to the upper levels so as to bring water from the bottom upwards.

9. A heat exchanger according to claim 2, characterised by the fact that the half- part (3b) of the casing has two connectors on the side of the C, one being a lower one (40) via which the cold water enters, and the other an upper one (41) via which the hot water flows out.

10. A heat exchanger according to claim 2, characterised by the fact that, at the bottom of the U-shaped element, there is an element (25) that creates a seat and a space to collect the condensation produced in the inner seat where the fumes pass, the said element being triangular-shaped and comprising a condensation discharge pipe (25a) and an opening (25b) for the discharge of the exhausted fumes that have passed within the two half-shells.

1. A heat exchanger according to claim 1 , characterised by the fact that the said exchanger is preferably made of aluminium or special aluminium alloys so as to resist corrosion, to have high thermal conductivity and be die-castable, the said alloys being of the low-melting type and requiring less energy to melt.