Filter for intercepting circulating solid mixture in heating system

Abstract

A mesh filter (2) capable of intercepting and retaining a solid mixture carried along a heat transfer fluid of a heating system, the system being provided with at least one heat generator comprising at least one burner, at least one primary circuit provided with at least one primary exchanger, at least one secondary circuit provided with at least one secondary exchanger, the heat generator is operable according to at least two operating modes: a CH mode in which the heat transfer fluid heated in the main exchanger is used for room heating; dHW mode in which the heat transfer fluid heated in the primary exchanger is sent to the secondary exchanger to heat and produce domestic hot water; a mesh filter (2) is mounted in the vicinity of a bifurcation or connection present or obtained / defined in the heat generator so as to be hit by a heat transfer fluid in CH and DHW modes, positioned and shaped such that: in the DHW mode, solid mixture is prevented from passing to the secondary exchanger; in the CH mode, accumulation of any intercepted and retained solid mixture is cleared by flow of the heat transfer fluid.

Description

Technical Field

[0001] The object of the present invention is a filter for intercepting and retaining solid mixtures circulating in a heating system or similar systems.

[0002] More specifically, the present invention relates to a mesh filter for intercepting and retaining solid mixtures circulating in a closed-loop heating system or similar systems.

[0003] More specifically, the present invention relates to a mesh filter adapted to protect and safeguard components of a general heat generator equipped with a reduced channel cross-section. Background Art

[0004] It is well known that in heating systems, especially in closed-loop heating systems, solid mixtures may form due to corrosion and precipitation phenomena of substances dissolved in the heat transfer fluid, usually water or aqueous solutions.

[0005] Once separated and dragged by the heat transfer fluid flow, such solid mixtures may cause problems to certain components inside the heat generator or in the same heating system.

[0006] Generally, the components most affected and suffering the most difficulties due to the presence of these solid mixtures are those equipped with a reduced / small channel cross-section, such as circulators, flow meters, and / or heat exchangers, especially exchangers using the hard brazed plate technology.

[0007] In fact, once separated from the heat transfer fluid, the said solid mixtures circulate in the heating system and tend to deposit near or block cross-sections with a smaller diameter, thus reducing their channel cross-section.

[0008] Currently, among the most widely used solutions for safeguarding such components are filters, especially mesh filters.

[0009] Such mesh filters, even if they can effectively intercept solid mixtures to prevent them from reaching and blocking the channel cross-section of the aforementioned components, still have some drawbacks.

[0010] In fact, over time, the amount of solid mixtures blocked by the filter increases, thus forming accumulations that ultimately lead to the clogging / blocking of the same filter.

[0011] To restore the function of the filter and ensure the correct circulation of the heat transfer fluid, it is necessary to remove such accumulations by cleaning or replacing the filter.

[0012] This requires the filter to be accessible and inspectable by the operator, and the cleaning or replacement operation of the filter normally requires emptying the closed loop of the heating system, cleaning / replacing the filter, refilling the closed loop, and subsequent degassing.

[0013] Degassing is required to eliminate the air that may enter the closed circuit during the evacuation / filling step, to ensure the normal operation of the system and maintain the reliability of the components, thus avoiding possible phenomena of micro-boiling and / or local overheating.

[0014] Therefore, it is clear that the maintenance for cleaning or replacing the filter is very laborious, requiring the emptying / filling of the system circuit, thus increasing the cost and the intervention time. Summary of the Invention

[0015] The object of the present invention is to avoid such drawbacks by providing an improved mesh filter for intercepting and retaining the solid mixture circulating in the heating system, which is capable of protecting and safeguarding the components of the heating system, in particular those equipped with a reduced channel cross-section, from the accumulation of the solid mixture.

[0016] For at least one or more implementation variants, another object of the present invention is to provide a mesh filter for intercepting and retaining the solid mixture circulating in the heating system, which is capable of reducing the number and complexity of the cleaning operations of the same mesh filter.

[0017] For at least one or more implementation variants, another object of the present invention is to provide a mesh filter for intercepting and retaining the solid mixture circulating in the heating system, the cleaning of which does not require the operation of emptying and subsequently filling the system circuit.

[0018] For at least one or more implementation variants, another object of the present invention is to provide a mesh filter for intercepting and retaining the solid mixture circulating in the heating system, which is simple to produce and easy to install.

[0019] Another object of the present invention is to provide a heating system that is capable of facilitating the cleaning of the mesh filter, thus avoiding the operation of emptying and subsequently filling the system circuit.

[0020] Another object of the present invention is to provide a heat generator that is capable of protecting and safeguarding the components, in particular those equipped with a reduced channel cross-section, from the accumulation of the solid mixture by adopting the mesh filter.

[0021] This object and other objects that will become apparent hereinafter are achieved by means of the mesh filter according to the independent claims.

[0022] Other objects can also be achieved by the additional features of the dependent claims. Brief Description of the Drawings

[0023] Other features of the present invention will become more apparent from the following description of the preferred embodiments, which are shown by way of non-limiting example only in the accompanying drawings and in accordance with the patent claims. In the drawings:

[0024] - Figure 1 A schematic view of a possible heat generator of a general heating system provided with a mesh filter according to the present invention is shown;

[0025] - Figure 2 Shows Figure 1 a detailed view of;

[0026] - Figure 3a Shows Figure 2 a detailed view of the mesh filter of during operation in DHW (domestic hot water) mode;

[0027] - Figure 3b Shows Figure 2 a detailed view of the mesh filter of during operation in CH (central heating) mode;

[0028] - Figure 4 Shows Figure 2 a detailed view of the mesh filter of during operation in exhaust / deaeration mode;

[0029] - Figure 5 A perspective view of a possible implementation variant of the mesh filter according to the present invention is shown;

[0030] - Figure 6 Shows Figure 5 a perspective view of the mesh filter of;

[0031] - Figure 7 Shows Figure 5 a side view of the mesh filter of;

[0032] - Figure 8 Shows Figure 5 a top view of the mesh filter of;

[0033] - Figure 9 Shows Figure 5 a rear view of the mesh filter of;

[0034] - Figure 10 Shows Figure 9 a cross-sectional view of the mesh filter of. DETAILED DESCRIPTION

[0035] The features of the deaerator according to the present invention will now be described using the reference numerals included in the drawings.

[0036] It should be noted that any dimensional and spatial terms that may be used hereinafter (such as "lower", "upper", "inner", "outer", "front", "rear", "vertical", "horizontal" and similar terms) refer, unless otherwise specified, to the position based on which the object of the present invention shown in the figures is arranged in the operating state.

[0037] Hereinafter, the term "mesh filter" should be understood as a device capable of intercepting and retaining the solid mixture carried by the heat transfer fluid along the heating system.

[0038] Without any intention of limitation, "solid mixture" should be understood as all those foreign objects that circulate with the heat transfer fluid, such as rust and / or limestone aggregates or the like.

[0039] The mesh filter according to the present invention can be installed on different heating systems, preferably heating systems of the closed-loop type, which include at least one general heat generator, such as a gas boiler and a condensing boiler or the like.

[0040] Without any intention of limitation, hereinafter, a closed-loop heating system provided with at least one heat generator, mainly a gas boiler or the like, will be mentioned. This heating system is equipped with the components necessary for its operation, but does not include all those components and / or accessories that may be installed along the heating system or on the heat generator, and these components and / or accessories do not form the object of this specification.

[0041] The reference numeral 1 as a whole represents a general heat generator 1 that can be installed in a general heating system.

[0042] As Figure 1 shown, the heat generator may include a gas boiler, especially a condensing gas boiler, in which the components required for its operation well-known to those skilled in the art are accommodated; only those components that are exactly relevant to the object of the present invention are mentioned herein.

[0043] The heat generator 1, hereinafter referred to as boiler 1, includes:

[0044] - at least one main circuit 100 and at least one secondary circuit 200, both of which are intended to heat water through at least one corresponding heat exchanger, namely the main heat exchanger 101 for the heat transfer fluid, hereinafter referred to as "main exchanger 101" and the secondary heat exchanger 202 for domestic hot water, hereinafter referred to as "secondary exchanger 202"; and

[0045] - at least one burner 10, which is located in the combustion chamber 110, and the combustion chamber 110 at least further accommodates the main exchanger 101.

[0046] The boiler 1 may further include at least one circulation pump 12 capable of circulating the heat transfer fluid, a possible expansion vessel 15, a forced ventilation device 16 capable of regulating the combustion air leading to the burner 10, and at least one gas valve 153 suitable for regulating the flow rate of the fuel gas supplied to the burner 10.

[0047] The main circuit 100 may include:

[0048] - At least one of the main exchangers 101, which in the example of the preferred variant in the figure consists of a helical coil exchanger;

[0049] - A supply pipe 112 for the heat transfer fluid, from which the heat transfer fluid starts from the main exchanger 101 and is sent via the outlet 140 to the heating element (not shown) of the heating system;

[0050] - A return pipe 111, which guides the heat transfer fluid from / to the heating element of the heating system through the inlet 144 to the main exchanger 101, where the fluid can be heated again by the burner 10;

[0051] - A circulation pump 12, which is preferably located on the return pipe 11; preferably, as shown in the figure, the pump 12 may include a degassing device 120 to remove the air bubbles formed in the heat transfer fluid;

[0052] - At least one diverter valve 40, which is preferably of the motorized three-way type, for switching the operating mode of the boiler 1 described later;

[0053] - Possible filling tap 60, drain tap 61, safety valve 62, all of which are preferably according to the prior art.

[0054] The main circuit 100 further includes an inlet pipe 121, which is led out from the supply pipe 112 and is suitable for making the heat transfer fluid flow towards the secondary exchanger 202, and then leaving the secondary exchanger 202 through at least one outlet pipe 122 and reaching the return pipe 111 of the main circuit 100.

[0055] The secondary circuit 200 may include:

[0056] - At least one of the secondary exchangers 202, which is preferably of the plate type;

[0057] - At least one delivery pipe 224, which delivers domestic hot water to the user through the outlet 241;

[0058] - At least one cold water supply pipe 223, through which cold water enters the secondary exchanger 202 through the inlet 243, and the cold water is heated by the heat transfer fluid passing through the secondary exchanger 202 to produce domestic hot water to be delivered to the user through the delivery pipe 224.

[0059] The boiler 1 can be operated in at least two possible operating modes:

[0060] - CH (central heating) mode, in which the heat transfer fluid heated in the main exchanger 101 is used for room heating via the heating elements of the heating system;

[0061] - DHW (domestic hot water) mode, in which the heat transfer fluid heated in the main exchanger 101 is sent to the secondary exchanger 202 to heat and produce domestic hot water.

[0062] When the heat transfer fluid follows the CH mode path, it passes through the main exchanger 101, the supply pipe 112 and reaches the heating system, and passes through the return pipe 111 when it returns from the system.

[0063] When the heat transfer fluid does not follow the CH mode path but is diverted to pass through the secondary exchanger 202 via the aforementioned inlet pipe 121 and outlet pipe 122, the boiler 1 operates in DHW mode.

[0064] The switching of the diverter valve 40 determines whether the boiler 1 operates in DHW mode or CH mode, where:

[0065] - In DHW mode, the valve 40 diverts the flow of the main circuit 100 via the inlet pipe 121 to the secondary exchanger 202;

[0066] - In CH mode, the valve 40 diverts the flow of the main circuit 100 via the outlet 140 to the heating body of the heating system.

[0067] Obviously, in both cases, the delivered thermal power depends on the required thermal power.

[0068] The diverter valve 40 is preferably arranged along the outlet pipe 122.

[0069] The boiler 1 further includes at least one control unit that can manage at least the burner 10 and the diverter valve 40 to implement the CH mode or the DHW mode.

[0070] The boiler 1 may also be equipped with at least one vent valve 151.

[0071] In addition, the boiler 1 may be equipped with a plurality of different sensors, such as:

[0072] - At least one temperature sensor 130 for the delivery of the heat transfer fluid; and / or

[0073] - At least one temperature sensor 131 for the return of the heat transfer fluid; and / or

[0074] - At least one pressure gauge 132; and / or

[0075] - at least one sensor 133, which is adapted to detect the pressure of the heat transfer fluid; and / or

[0076] - a flow meter 134, which is adapted to detect the flow rate / quantity of domestic water requested by the user.

[0077] If some components and operations of the heating system or heat generator 1 are concepts known to those skilled in the art, then, as has been partly anticipated, they will not be further described and detailed herein.

[0078] According to the present invention, the heat generator 1 is characterized in that it is equipped with a mesh filter 2 according to the present invention.

[0079] The mesh filter 2 according to the present invention can be installed / located in a general heat generator, such as a boiler 1, and is characterized in that it can be hit by the heat transfer fluid in both the CH mode and the DHW mode.

[0080] Generally speaking, the mesh filter 2 according to the present invention is advantageously positioned and shaped such that:

[0081] - in the DHW mode, it prevents the solid mixture from passing through the inlet pipe 121 and towards the secondary exchanger 202, Figure 3a ;

[0082] - in the CH mode, the possible accumulation of the solid mixture intercepted and retained by it is removed by the flow of the heat transfer fluid, and then the mixture is removed by the heat transfer fluid and carried towards the heating system, where they may be deposited without causing problems to the components of the boiler 1, Figure 3b 。

[0083] Substantially, in the DHW mode, the mesh filter 2 prevents the solid mixture from passing through the inlet pipe 121 and reaching the secondary exchanger 202, thus ensuring its functionality and service life, while in the CH mode, the heat transfer fluid hitting the surface of the mesh filter 2 acts on / aligns with the solid mixture accumulated on the same filter 2, thereby moving it and carrying it to other places, and releasing / cleaning the mesh filter 2.

[0084] Therefore, it can be seen that according to the present invention, it is sufficient to switch the boiler 1 to the CH mode and start the pump 12 to clean the mesh filter 2.

[0085] Therefore, each time the boiler 1 is switched from the DHW mode to the CH mode, the filter 2 is cleaned, and the switching:

[0086] - depends on the normal operation of the boiler 1, which should be operated to meet, for example, the room heating and domestic hot water requests during winter; or

[0087] - is requested via possible control modes described later.

[0088] The heating system according to the invention is characterized in that it comprises a heat generator equipped with said mesh filter 2, which is positioned in the heat generator 1 so that it can be hit by the heat transfer fluid both in CH mode and in DHW mode and its cleaning requires switching the boiler 1 to CH mode.

[0089] For this purpose, the mesh filter 2 can be installed near a fork or connection, preferably of “T” type or similar type, which is present in the heat generator 1 or is appropriately obtained / defined in the heat generator 1, preferably positioned along a section of the supply pipe 112 located upstream of the inlet pipe 121.

[0090] Preferably, referring to the boiler 1 exemplarily shown in the drawings, the mesh filter 2 may be installed along the supply pipe 112 at a point where the pipe 112 is inserted / connected to the inlet pipe 121 .

[0091] For this purpose, the supply conduit 112 may be formed to have an elbow / bend on which a T-fitting or the like may be inserted or defined.

[0092] According to possible implementation variations, the supply pipeline 112 comprises at least:

[0093] a first section 112a extending from the main exchanger 101 to which it is suitably connected to a second section 112b; and

[0094] - The second section 112b is basically arranged as follows:

[0095] - orthogonal to the first section 112a and the third section 112c, and

[0096] - coplanar with the inlet duct 121 to which it is suitably connected, said second section 112b being able to at least partially house said mesh filter 2; and

[0097] The third section 112 c , which extends from the second section 112 b to the outlet 140 .

[0098] In essence, the first section 112a and the third section 112c may be arranged substantially vertically, while the second section 112b may be positioned substantially horizontally.

[0099] With this possible configuration of the supply conduit 112, the mesh filter 2 can be positioned near a "T" piece or the like so that it can be hit by the heat transfer fluid both in CH mode and in DHW mode.

[0100] The mesh filter 2 can be fixed to the inner wall of the second section 112b or the connection or bifurcation through, for example, a form connection, a joint, an interference fit or a similar fit, or by using glue or the like.

[0101] Generally, the mesh filter 2 is suitably shaped to be accommodated in the bifurcation or connection or the second section 112b and to enable the heat transfer fluid to:

[0102] - be sent towards the inlet pipe 121 when the boiler 1 operates in DHW mode, and the fluid is filtered by the mesh filter 2 before reaching the secondary exchanger 202, Figure 3a ;

[0103] - be sent towards the third section 112c when the boiler 1 operates in CH mode, and the fluid flushes and cleans the mesh filter 2, Figure 3b 。

[0104] According to a preferred variant, the boiler 1 can provide a control mode, preferably managed and implemented by a control unit, which is capable of performing / commanding a spontaneous switch to the CH mode after the boiler 1 has been operating in DHW mode for a long time, in order to clean the mesh filter 2 at regular intervals, so as to keep its filtering power high and / or avoid its clogging / blocking.

[0105] The control mode provides tracking / storing of the switching of the diverter valve 40 via the control unit, so as to be able to monitor how much time has elapsed since the last switch and thus to determine how long the boiler 1 has been operating in DHW mode or CH mode.

[0106] In this way, during the control mode, it is possible to determine in which mode the boiler 1 is operating and for how long, and if the length of time the boiler has been operating in DHW mode is longer than a preset reference duration, a spontaneous switch to the CH mode is implemented.

[0107] The control mode can be autonomously executed by the boiler 1 at regular intervals set by the manufacturer and / or installer and / or user or upon request, for example, via the control panel.

[0108] The reference duration can be set and possibly modified by the manufacturer and / or installer and / or user and can be equal to, for example, one month or several times or fractions thereof.

[0109] Therefore, if during the DHW mode the control mode detects that the reference duration has been exceeded, it provides a spontaneous switch to the CH mode by switching the diverter valve 40 and starting the pump 12.

[0110] This control mode is particularly useful during the summer months, during which the boiler 1 generally operates only in DHW mode for a long time; generally, long time means at least one month.

[0111] It should be noted that this spontaneous switch from the DHW mode to the CH mode is carried out in such a way as not to interfere with the normal operation of the boiler 1, for example, it is not carried out during the delivery of domestic hot water.

[0112] During the winter period, during which the boiler 1 operates frequently in the CH mode and switches from one mode to the other, the cleaning of the filter 2 is carried out regularly every time there is a switch from DHW to CH.

[0113] However, if the boiler 1 does not operate frequently in the CH mode, there is nothing to prevent the said control mode, which may be suspended during the winter period, from remaining active at all times, so as to ensure the cleaning of the filter 2 even during the winter period.

[0114] According to a possible implementation variant as described in the non - restrictive example in the attached drawings, the heat generator 1 may also be provided with an exhaust / degassing system 7.

[0115] The exhaust system 7 may include a drain valve or tap or the like, preferably of the manual type.

[0116] Generally speaking, the drain valve 7 allows the execution and acceleration of the air - discharging step during the step of filling the circuit of the heating system or during the maintenance operation of the generator 1.

[0117] According to a preferred variant, the drain valve 7 may be positioned along the supply pipe 112, preferably along the third section 112c downstream of the mesh filter 2.

[0118] In this case, the drain valve 7 can also be advantageously used, preferably when the pump 12 is not operating, to carry out the cleaning of the mesh filter 2 without the boiler 1 having to switch to the CH mode.

[0119] In fact, when the drain valve (cleaning valve) 7 is opened manually or electrically, a heat - transfer fluid flow is generated, which beats against and passes through the mesh filter 2, thus removing the solid mixture that may have been deposited and flowing out of the same drain valve (cleaning valve) 7. Figure 4 .

[0120] This heat - transfer fluid flow is basically generated by the pressure difference between the closed circuit of the heating system and the atmospheric pressure existing at the outlet of the drain valve 7, and tends to remove the accumulated solid mixture and discharge it into the condensate and over - pressure exhaust passages already present / provided in the boiler.

[0121] It should be noted that this use of the valve 7 to clean the filter 2 can be provided in addition to or as an alternative to the cleaning carried out in the CH mode.

[0122] According to Figures 5 to 10Possible implementation variants described by way of non - limiting examples, the mesh filter 2 may include a hollow body provided with:

[0123] - a first part 21, which has a substantially hollow cylindrical shape, and the first part is capable of:

[0124] - being received, preferably by interference fit or interlocking, in the bifurcation or connection of the boiler 1 or in the second section 112b of the supply pipe 112, and

[0125] - serving as a support for the second part 22; and

[0126] - one said second part 22, which projects from the first part 21 and is provided with a plurality of openings 220 for the passage of the heat - transfer fluid, the second part 22 substantially defining the filtering section of the mesh filter 2 and being substantially tangentially slapped by the heat - transfer fluid in the CH mode.

[0127] When the heat - transfer fluid reaches the mesh filter 2, it passes through the first part 21, reaches the second part 22, and depending on the operating mode of the boiler 1, it either flows towards the third section 112c and slaps the second part 22 or flows towards the inlet pipe 121 and passes through the second part 22.

[0128] The dimensions of the different parts 21 and 22 of the mesh filter 2 are such that once the mesh filter 2 is installed in the bifurcation or connection or the second section 112b, then:

[0129] - the first part 21 ensures a stable connection with the bifurcation or connection or the second section 112b, thus ensuring the position / stability of the filter 2;

[0130] - the second part 22 substantially extends up to the junction of the inlet pipe 121 and has a transverse extension similar to the cross - sectional area of the passage of the inlet pipe 121 to filter the entire flow entering it.

[0131] According to possible implementation variants described by way of non - limiting examples in the drawings, the second part 22 provides a skewed / slanted longitudinal extension that gradually decreases ( Figure 10 ) towards its free / projecting end 221 when the longitudinal extension moves away from its end integral with the first part 21.

[0132] This skewed extension of the second part 22 facilitates the removal of the solid mixture in the CH mode by the heat - transfer fluid that substantially tangentially slaps it.

[0133] In fact, the skew extension diverts / guides the flow, thus forcing it to fully strike the second part 22 in order to improve the interaction with the retained solid mixture and thus improve its removal.

[0134] According to a preferred variant, the second part 22 may be substantially in an "L" shape and provides:

[0135] - A first section 222, which is integral with the first part 21 of the filter 2 and is adapted to serve as a support for the second section 221;

[0136] - The second section 221, which projects substantially orthogonally from the first section 222 to define the free end 221;

[0137] Both the first section 222 and the second section 221 are advantageously provided with the opening 220.

[0138] Preferably, the first section 222 defines the skew / tilt portion of the second part 22.

[0139] According to a possible implementation variant described by way of non-limiting example in the drawings, the mesh filter 2, in particular the free end 221 of the second part 22, may have a curved profile.

[0140] Preferably, the free end 221 may have an outward curvature, that is to say, once the filter 2 is installed in the bifurcation or connection or the second section 112b, the free end 221 bends / bulges towards the inlet duct 121.

[0141] More preferably, the free end 221 has a horizontal curvature (a curved portion in the horizontal direction), that is, its radius of curvature is parallel to the longitudinal symmetry axis of the mesh filter 2.

[0142] This curved profile facilitates the removal of the solid mixture during the cleaning operation of the mesh filter 2.

[0143] According to different embodiments, the mesh filter 2 may be made of different materials, preferably made of a material resistant to corrosion / rust or the action of heat transfer fluids, such as a metal or plastic material.

[0144] Similarly, the mesh filter 2 may be an assembly / union of different components, or may be made as a single piece, for example, by molding.

[0145] The mesh filter 2 according to the present invention is capable of intercepting and retaining the solid mixture circulating in a general heating system, such as the above-mentioned heating system, in order to protect and safeguard the components, in particular the components equipped with a reduced channel cross-section, from the accumulation of the same solid mixture.

[0146] The mesh filter 2 according to the invention allows for easier and faster cleaning operations without the need to empty and subsequently fill and degas the system circuit.

[0147] Finally, it should be noted how easily and quickly the mesh filter 2 can be installed on the heat generator and coupled to the fork, connection or second section 112b.

[0148] In fact, the installation of the mesh filter 2 requires insertion and coupling to the fork, connection or second section 112b as described above.

[0149] It is clear that for a person skilled in the art, there can be several variants of the above-described invention without departing from the scope of novelty of the inventive concept; it is also clear that in the actual embodiments of the invention, the various components described above can be replaced by technically equivalent components.

[0150] For example, the mesh filter 2, in particular its parts 21 and 22, can be modified and shaped so as to be able to be installed and better fit different types of forks or connections or different configurations of the supply pipe 112, and thus be able to be installed on different types of heat generators.

[0151] In fact, the pipe 112 can be without the second section 112b and thus be straight; in this case, the filter 2 can be appropriately shaped so as to be able to be preferably installed in the inlet pipe 121 and guarantee the above-described filtering characteristics and cleaning mode.

Claims

1. A heat generator (1) which can be installed in a general heating system, the heat generator (1) comprising: - At least one main circuit (100), the at least one main circuit being provided with at least one main exchanger (101), at least one heat transfer fluid supply pipe (112), at least one return pipe (111) and at least one inlet pipe (121) derived from the supply pipe (112), the inlet pipe being adapted to direct the heat transfer fluid towards a secondary exchanger (202), the heat transfer fluid leaving the secondary exchanger (202) via at least one outlet pipe (122) and reaching the return pipe (111); - At least one secondary circuit (200), the at least one secondary circuit being provided with at least one secondary exchanger (202), at least one delivery pipe (224), at least one supply pipe (223) for cold water entering the secondary exchanger (202), the cold water being heated by the heat transfer fluid passing through the secondary exchanger (202) to produce domestic hot water to be sent to users through the delivery pipe (224); - At least one burner (10); - At least one control unit; - At least one circulation pump (12) which can circulate the heat transfer fluid; - At least one diverter valve (40) for switching the operating mode of the heat generator (1), The heat generator (1) can operate according to at least two possible operating modes: - CH mode, in which the heat transfer fluid heated in the main exchanger (101) is used for room heating; - DHW mode, in which the heat transfer fluid heated in the main exchanger (101) is sent to the secondary exchanger (202) to heat and produce domestic hot water; Characterized in that The heat generator is equipped with a mesh filter (2), the mesh filter being capable of intercepting and retaining solid mixtures carried by the heat transfer fluid along the heating system, the mesh filter (2) being positioned along the heat generator (1) so as to be hit by the heat transfer fluid in both the CH mode and the DHW mode, The mesh filter (2) is positioned and shaped such that: - In the DHW mode, it prevents solid mixtures from reaching the secondary exchanger (202); - In the CH mode, any accumulation of solid mixtures intercepted and retained by the mesh filter is removed by the flow of the heat transfer fluid, And wherein The mesh filter (2) comprises a body, the body being provided with: - A first part (21), the first part having a substantially hollow cylindrical shape, the first part being capable of: - Being received in a bifurcated portion or a connecting portion of the heat generator (1); and - Serving as a support portion for a second part (22); and - One such second part (22), the second part (22) protruding from the first part (21) and being provided with a plurality of openings (220) for the heat transfer fluid to pass through, the second part (22) defining the filtering section of the mesh filter (2), Wherein, the second part (22) provides a skew / tapered longitudinally extending portion that gradually decreases towards its free end (221) when moving away from the end where it is integral with the first part (21).

2. The heat generator (1) according to claim 1, characterized in that, The mesh filter (2) is mounted along the supply pipe (112) at the point where the inlet pipe (121) is inserted / connected to the supply pipe (112).

3. The heat generator (1) according to claim 2, characterized in that, The supply pipe (112) is shaped to have a bent head / bending portion on which a "T" - shaped connection portion can be engaged or defined.

4. The heat generator (1) according to claim 3, characterized in that, The supply pipe (112) at least includes: - A first section (112a) that extends from the main exchanger (101) to which it is connected to a second section (112b); - The second section (112b) which is arranged to be substantially orthogonal between the first section (112a) and the third section (112c) and substantially coplanar with the inlet pipe (121), and the second section (112b) can at least partially accommodate the mesh filter (2); - The third section (112c) that extends from the second section (112b) until the outlet (140).

5. The heat generator (1) according to claim 4, characterized in that, The mesh filter (2) is fixed to the inner wall of the second section (112b) or the connection portion or the bifurcation portion via a form - fit, a joint, an interference fit, or by using glue.

6. The heat generator (1) according to any one of the preceding claims, characterized in that, The heat generator (1) provides a control mode that can perform / command an automatic switch to the CH mode after the same heat generator (1) has been operating in the DHW mode for a long time to clean the mesh filter (2).

7. The thermal generator (1) according to any one of the preceding claims, characterized in that, The heat generator (1) is also provided with an exhaust / de - gassing system (7) that includes a drain valve positioned along the supply pipe (112), and the drain valve (7) can also be used to clean the mesh filter (2).

8. A mesh filter (2) that can intercept and retain the solid mixture carried by the heat - transfer fluid along a heating system, the heating system having at least one heat generator including at least one burner, at least one main circuit having at least one main exchanger, and at least one secondary circuit having at least one secondary exchanger, characterized in that the mesh filter (2) includes a body that is provided with: - A first part (21) having a substantially hollow cylindrical shape, and the first part can: - Be accommodated in the bifurcation portion or the connection portion of the heat generator; and - Serve as a support portion for the second part (22); and - A second part (22) that protrudes from the first part (21) and is provided with a plurality of openings (220) for the heat - transfer fluid to pass through, and the second part (22) defines the filtering section of the mesh filter (2), and wherein, The second part (22) provides a skew / tapered longitudinally extending portion which tapers towards its free end (221) as it moves away from the end where it is integral with the first part (21).

9. The mesh filter (2) according to claim 8, characterized in that, The free end (221) of the second part (22) has a curved profile.

10. A control mode for a heat generator (1) according to the preceding claims 1 to 7, the heat generator (1) being provided with a mesh filter (2) according to the preceding claims 8 and 9, the control mode being capable of performing / commanding a spontaneous switch of the heat generator (1) to the CH mode, the control mode providing: - Keeping track of / storing the switching of the diverter valve (40); - Determining in which mode the heat generator (1) is operating and for how long; - Implementing a spontaneous transition to the CH mode if the length of time for which the heat generator (1) is operating in the DHW mode is longer than a preset reference duration.

11. The control mode according to claim 10, characterized in that, The control mode is autonomously executed by the heat generator (1) at regular intervals set by the manufacturer and / or installer and / or user or on request.

12. The control mode according to claim 10 or 11, characterized in that, The reference duration can be set by the manufacturer and / or installer and / or user.

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