Patent Description:
The invention therefore falls within the field of high yield heat generators (with yields, referred to the Inferior Calorific Power, in the range of <NUM>-<NUM>%), in particular in that of condensing boilers for room heating and/or production of domestic hot water.

Generally, a boiler is a device wherein water to be heated (both for sanitary uses and rooms heating), runs through a heat exchanger cooperating with a gas burner. Said gas burner may comprise a pipe bundle, preferably spiral wound, being said turns crossed by combustion gases, or fumes, generated by the gas burner, so as to transfer heat to the water running through it.

Said combustion gases, after having transferred their heat to water, including the latent condensation heat, are discharged outside of the exchanger and of the gas boiler.

Said boilers have been perfected and improved over time, so as to provide the user with increasingly safe and performing devices.

Currently, one of the major problems regarding the boilers, is given by the temperature control both of the water delivered and of the same heat exchanger. As for the water delivered, it is important to know its temperature so as to verify whether the boiler is working according to the parameters required and set by the user.

For example, if the boiler delivered water colder than the set temperature, it should work longer in order to reach the desired thermal comfort or, in case it was used for sanitaryware, it would create discomfort to the user.

Moreover, a punctual and accurate control of the temperature of the exchanger allows preventing breakages or damages to the system.

In fact, in the event that the burner was activated without water in the heat exchanger, said exchanger would overheat causing structural damages that may compromise the operation and/or integrity thereof.

For example, the pipe bundle may deform or pierce due to the flames and the strong heat, affecting its functionality irreversibly.

Another problem of particular concern for the condensing boilers is due to the impossibility or difficulty of regulating and/or modifying the dimensions of the combustion chamber.

The solutions proposed so far from the prior art are insufficient.

For example heat exchangers have been developed provided with temperature probes or sensors, so as to monitor the temperature thereof.

patent No. <CIT> describes a water heater with the features of the preamble of claim <NUM>, in particular a heater for the production of hot water capable of recovering the heat coming from the combustion gas generated by a burner.

Said heater comprises a burner, a fan for the supply of air for the combustion, a heat exchanger wherein the fuel gas together with air is delivered, a water pipe that recovers the sensitive heat and the latent heat from the combustion gas, a control unit, provided with a data table, adapted to regulate said fan based on the data of said table.

At the inlet and outlet of the exchanger, the heater is further provided with temperature sensors (not described); the combustion level is determined based on the water inlet and outlet temperature values.

The heater comprises a fixed partition dividing the combustion chamber into two different and not modifiable zones.

However, according to the prior art, said temperature sensors or probes, are positioned on the connecting unions or sleeves joining the end of the exchanger with the pipes of the heating or sanitaryware hydraulic system; this limits the sensitivity of said sensors.

Normally, said connecting unions or sleeves facilitate the connection between the end of the exchanger, not always easily accessible or reachable, and said pipes. Said connecting unions or sleeves are usually made of plastics or the like, and have relatively low heat transmission coefficients.

This leads the thermal probe to operate with delay and inaccuracy, generating measuring errors and low readiness of the boiler, or in general of its control means, to react in order to bring the measured parameters in line with the set parameters. In other cases, because of the reduced spaces available and in order to guarantee easy access, said temperature sensors or probes are not installed in the immediate vicinity of the ends of the exchanger, and the data they measure may be affected by the distance of the sensor from the water inlet and outlet point.

Another example of exchanger is illustrated in the U. patent No. <CIT> that shows a heat exchanger for a gas boiler for the production of hot water, comprising an enclosure, a pipe forming a plurality of coils wherealong water runs, deflector means to guide the combustion fumes and spacer means in order to space the turns from each other.

Said exchanger comprises a disc, not better described but of solid shape, dividing into two the combustion chamber.

Said disc, presumably made of refractory material, is difficult to produce, due to the envisaged coupling with the coils of the pipe bundle, and the document does not illustrate any ways for producing or installing it.

As is known, in fact, the refractory materials require more complex production steps, particularly if particular geometric shapes are provided.

The object of the present invention is to solve the problems described above, by providing a heat exchanger capable of readily and correctly detecting the temperature of the heat transfer fluid crossing it.

A further object of the present invention, at least for one or more executive variants, is to provide an exchanger allowing a direct connection between its ends and the hydraulic pipes.

A further object of the present invention, at least for one or more executive variants, is to provide an exchanger that allows varying the dimensions of the combustion chamber of a condensing boiler, in particular that allows varying the dimensions of the "sensitive chamber" and of the "condensing chamber" of said combustion chamber.

These and other objects, which shall appear clear hereinafter, are achieved with a heat exchanger, illustrated in the following description and in the annexed claims, which constitute an integral part of the description itself.

Further features of the present invention shall be better highlighted by the following description of a preferred embodiment, in accordance with the patent claims and illustrated, purely by way of a non-limiting example, in the annexed drawing tables, in which:.

Unless where otherwise specified, in this report any possible spatial reference such as the terms "up/down, front/rear, right/left etc." refers to the position in which the elements are represented in the annexed figures.

With the purpose of highlighting some features instead of others, not necessarily what described in the annexed drawings is perfectly to scale.

The heat exchanger <NUM>, hereinafter for simplicity referred to as exchanger <NUM>, comprises a suitable container body <NUM>, at least one coil <NUM>, and at least one temperature sensor means <NUM>.

The term coil is to be intended as a pipe bundle made by a pipe <NUM>, preferably metallic, spiral wound around a central axis, adapted to form a suitable number of turns, and delimiting a combustion chamber <NUM> wherein the fumes produced by a burner (not shown) are introduced.

Said coil <NUM> is advantageously made as a single component, i.e., it is defined by a seamless single element.

The coil <NUM> is thus devoid of welds and/or junctions; this favours a uniform and homogeneous deformation, due to the temperatures to which it is subject.

The coil <NUM> provides at least a first end <NUM>, which acts as an inlet for the heat transfer fluid to be heated, and at least a second end <NUM>, which acts as an outlet for said heat transfer fluid.

According to a preferred variant, said coil <NUM> has an elliptical section, while said ends <NUM> and <NUM> has a circular section that eases the operations of connection to the pipes of the water system or to any mechanical components (adjusting valves, pumps, etc.).

Advantageously, said ends <NUM> and <NUM> are obtained by shaping the elliptical section by known mechanical processes for plastic deformation, so as to obtain a change of section, from elliptical to circular, without the help and the mounting of additional elements such as unions, manifolds or the like; this allows a metallic continuity between the exchanger and the pipes.

Vice versa, still with known processes, the section of the coil <NUM> is deformed from circular to elliptical except for said ends <NUM> and <NUM>.

The exchanger <NUM> according to the present invention is characterised in that the ends <NUM> and <NUM> project from the container body <NUM>, in such extent as to guarantee an easy access to the same.

In general, the container body <NUM> may be made according to different executive variants, all characterised in that the ends <NUM> and <NUM> of the coil <NUM> project from said container body <NUM>.

Such feature, in accordance with the exchanger according to the present invention, advantageously allows positioning and installing the sensor means <NUM> on said ends <NUM> and <NUM>.

This way the sensor means <NUM> are able to measure the temperature of the water in the immediate vicinity of the inlet and/or outlet of the exchanger <NUM>, avoiding any alteration of the data detected due to the distance between the end of the exchanger and the position of the sensor.

Further, according to said embodiment variant, the sensor means <NUM> are advantageously in direct contact with the metal walls of the coil <NUM>, so as to control its temperature more effectively.

Such arrangement allows measuring the temperature of the coil <NUM> more accurately and faster, solving the problems of the prior art illustrated above.

In fact, the metallic walls of the coil <NUM> have higher heat exchange coefficients than the plastic materials used for the unions or the like currently used and the sensor means <NUM> may detect the temperature value faster and more promptly.

Further, since the ends <NUM> and <NUM> project from the container body <NUM>, said sensor means are easily accessible and reachable from outside; this allows easy and quick maintenance and/or change of the same.

Said sensor means <NUM> maybe constrained and fixed to the end <NUM> and <NUM> of the coil <NUM> through suitable mounting means <NUM>.

According to a first embodiment variant, shown in <FIG>, said mounting means <NUM> comprise the fixing means, such as for example the metal clips, which carry out the locking of the said ends <NUM> and <NUM> with the pipes of the heating hydraulic system or of the sanitaryware (not illustrated).

In fact, thanks to the projection of the ends <NUM> and <NUM> from the container body <NUM>, it is possible to avoid the use of the current unions or sleeves, carrying out a direct connection between said ends <NUM> and <NUM> and the pipes, said connection being guaranteed and carried out by said fixing means.

Said fixing means, therefore, carry out and ensure the attachment of the exchanger to the pipes and do not carry out any connecting function between the parts, i.e. the water flows directly from the pipe to the first end <NUM> and from the second end <NUM> to the pipe.

In order to ease the connection of the parts and obtain a stable and secure connection, said ends <NUM> and <NUM> may be provided with suitable collars <NUM>.

Said collars <NUM> are obtained and defined at the inlet of said ends <NUM> and <NUM> and cooperate with said fixing means.

Nothing prevents said fixing means <NUM> from comprising, for example, couplable half-shells, straps, clamps, or the like.

Said ends <NUM> and <NUM> may be arranged according to different executive variants, provided by way of a non-limiting example.

For example, said ends <NUM> and <NUM> may be arranged with the reciprocal longitudinal axes parallel to each other (variant not illustrated) or may be arranged with the reciprocal longitudinal axes orthogonal to each other (<FIG>).

Said last variant, shown in the accompanying figures, allows having the end <NUM> substantially horizontal relative to the exchanger <NUM> (<FIG>); this allows easily installing a deaerator <NUM>, substantially a device used to eliminate air or gas contained in hydraulic systems or the like, and improving the release and venting of the air.

Moreover, being said end <NUM> projecting from the container body <NUM>, the installation of the deaerator <NUM> is of easy access for the operator, so as to ease him in the maintenance or change steps of the same.

Said exchanger <NUM> is advantageously provided with a partition <NUM>, particularly useful in the case of condensing boilers, provided with a suitable layer of insulating material <NUM>.

Said partition <NUM>, substantially a disc-shaped element, divides said combustion chamber <NUM> into two parts; a first exchanging chamber <NUM> called "sensitive exchanger" and a second exchanging chamber <NUM> called "cold exchanger" or "condensing".

As it is known, the first exchanging chamber <NUM> is exposed to the flames of the burner, and the fume flow occurs in a radial direction (i.e. orthogonal to the central axis of the exchanger <NUM>); therefore, each fume thread exchanges heat individually with a single turn of those present.

The partially cooled fumes are guided towards the second exchanging chamber <NUM>, where they are further cooled to such a temperature as to have the condensation of part of the water vapour contained therein and then sent to a stack (not shown) for being discharged to the atmosphere.

Said partition <NUM> prevents the direct communication between the respective first chamber <NUM> and second chamber <NUM>, guaranteeing the above described flow of the combustion fumes.

Moreover, said partition <NUM> is "screwed" along the turns of the coil <NUM>.

In substance, the partition <NUM> may be moved along said coil <NUM> with a rotary movement similar to screwing; this allows modifying the position of said partition <NUM> and thus regulating and varying the dimensions of the said chambers <NUM> and <NUM>.

For this purpose the partition <NUM> is shaped so as to provide a guiding slot to ease said screwing, in particular said partition <NUM> comprises a disc, preferably of sheet, having an outer profile <NUM> with helical pattern (<FIG>).

Such shape of the partition <NUM> simplifies the manufacture step, since it is possible to make a disc and shape the outer profile <NUM> thereof according to known techniques, and subsequently to suitably position and arrange the layer of insulating material <NUM>.

This allows obtaining the disc <NUM> according to the most advantageous and efficient manufacturing techniques, allowing to simplify the production process, and not to bind the manufacturer to make said partition <NUM> entirely of refractory material. Said shape of the partition <NUM> also eases the mounting and insertion of the same on the coil <NUM>.

According to a possible executive variant, provided by way of a non-limiting example, the container body <NUM> may comprise a suitably shaped bottom <NUM>, a shell <NUM> and a cover <NUM>.

Said bottom <NUM> and said cover <NUM> are couplable to each other through suitable fixing means, described below, so as to be able to house, in cooperation with said shell <NUM>, the coil <NUM>.

For this purpose a plurality of seats may be advantageously provided, suitably shaped and moulded, adapted to replicate and reproduce the outer profile of said coil <NUM>, so as to facilitate the insertion of the same in said bottom <NUM>.

For example the bottom <NUM> is provided with a seat <NUM> adapted to receive the end <NUM> of the coil <NUM>.

The complementarity of the surfaces of said bottom <NUM> and of said cover <NUM> with said coil <NUM>, avoids possible clearances or any gap that may lead to vibrations or movements of the coil <NUM> inside the container body <NUM>, perhaps during the transport or installation operations.

Said bottom <NUM> is further provided with suitable longitudinal projections <NUM>, substantially supports whereon said cover <NUM> is fixed, by screws or the like, so as to lock and clamp the various elements that make up said heat exchanger.

Said longitudinal projections <NUM> may be provided with threaded holes <NUM> whereon the screws <NUM> are screwed.

For this purpose said cover <NUM> may be advantageously provided with a plurality of appendices <NUM> extending radially outwards.

Said appendices <NUM> may be provided with through holes <NUM> whereon the screws <NUM> are inserted that screwing on said longitudinal projections <NUM>, clamp said cover <NUM> to said bottom <NUM>.

Moreover, said bottom <NUM> may be provided with suitable through holes <NUM> that allow the mounting and fixing of the exchanger <NUM> to the body of the boiler.

The shell <NUM> has a substantially cylindrical shape and may be advantageously made of metal, for example of stainless steel.

Moreover the shell <NUM> may be provided, entirely or partially, with a layer of insulating material capable of retaining the heat within the combustion chamber <NUM>, to the advantage of energy efficiency, and avoiding high temperature surfaces to be exposed, potentially critical and dangerous for the user and/or the mechanical and/or electrical devices arranged in the proximity of them.

Said shell <NUM> is advantageously placed and enclosed between said bottom <NUM> and said cover <NUM>.

According to a possible executive variant, the shell <NUM> is retained into position thanks to the coupling with suitable seats (not illustrated) provided and obtained on said bottom <NUM> and cover <NUM>.

In particular, the edges of the shell <NUM> insert and engage with suitable grooves and/or edges, whereon sealant may be advantageously placed.

Moreover, a channel <NUM> adapted to convey the condensation towards the condensation discharge <NUM> may be provided on the shell <NUM>.

The exchanger <NUM> according to the present invention provides and allows the ends <NUM> and <NUM> to project from the container body <NUM> wherein it is housed.

In particular, observing the figures, it is understood that said ends <NUM> and <NUM> project from the container body <NUM>, allowing the user to easily reach the same.

Such accessibility eases the connections of the pipes that, according to a preferred variant, takes place through fixing means, such as for example a metal clip, cooperating with the collars <NUM> obtained and defined at the inlet of said ends <NUM> and <NUM>.

In general, therefore, the container body <NUM> may be made according to different executive variants, all characterised in that the ends of the coil <NUM> project from said container body <NUM>.

It is clear that in the practical embodiment of the invention numerous modifications and further variants may be provided, all falling within the same inventive concept; all the various components and details previously described may also be replaced by technically equivalent elements.

Claim 1:
Heat exchanger (<NUM>) for gas condensing boilers, provided with a suitable container body (<NUM>), at least one pipe bundle (<NUM>), at least one temperature sensor means (<NUM>), where said pipe bundle (<NUM>) is made by a pipe (<NUM>) spiral wound around a central axis, adapted to form a suitable number of turns delimiting a combustion chamber (<NUM>), and provides a first end (<NUM>) which serves as an inlet for the heat transfer fluid to be heated, and a second end (<NUM>) which serves as an outlet for said heat transfer fluid, wherein said first and second ends (<NUM>; <NUM>) protrude from said container body (<NUM>),
wherein said exchanger (<NUM>) is provided with a partition (<NUM>) adapted to divide the combustion chamber (<NUM>) into a first sensitive chamber (<NUM>) and into a second condensing chamber (<NUM>),
wherein
- said partition (<NUM>) comprises a disc-shaped element having an outer profile (<NUM>) with helical pattern, provided with a layer of insulating material (<NUM>),
- said partition (<NUM>) is screwable along the turns of the pipe bundle (<NUM>), so as to regulate and vary the dimensions of the said chambers (<NUM>; <NUM>), and characterised in that
- said at least one temperature sensor means (<NUM>) is constrained and fixed to said first and second ends (<NUM>; <NUM>) through appropriate mounting means (<NUM>);
- said mounting means (<NUM>) (<NUM>) comprise the fixing means that carry out the locking of the said ends (<NUM>; <NUM>) with the pipes.