Heat exchange cell and method

Abstract

A heat exchange cell includes a helically-shaped heat exchanger, in which a first heat transfer fluid circulates; a first heat exchange chamber in which a first collection chamber is defined; a second heat exchange chamber in which a second collection chamber is defined; and a fluid outlet passage from the second heat exchange chamber. The first and second heat exchange chambers are separated by a first separating element comprising a substantially plate-shaped body and by at least a second separating element so as to define at least one passage of fluid between the first and the second collection chamber of the second heat transfer fluid. A pair of axial separator baffles extend axially between the second separating element and the rear wall of the containment casing, and are configured to separate a first portion of the second collection chamber from a second portion of the second collection chamber.

Claims

1. A heat exchange cell comprising: a containment casing comprising a rear wall and a peripheral side wall, a helically-shaped heat exchanger comprising a tubular duct for the flow of a first heat transfer fluid, the tubular duct being coiled about a longitudinal axis of a helix including a plurality of coils; said heat exchanger being mounted in said containment casing; a feeding zone of a second heat transfer fluid, intended for a heat exchange with said first heat transfer fluid, the feeding zone being defined in the casing coaxially and internally with respect to said heat exchanger; a first heat exchange chamber, defined in said containment casing and in which a first heat exchange portion of the heat exchanger is housed, said first heat exchange chamber comprising a first collection chamber of the second heat transfer fluid externally defined with respect to the heat exchanger between a radially outer wall of the first heat exchange portion of the heat exchanger and the peripheral side wall of the containment casing; a second heat exchange chamber, defined in said containment casing and in which a second heat exchange portion of the heat exchanger is housed, said second heat exchange chamber comprising a second collection chamber of the second heat transfer fluid externally defined with respect to the heat exchanger between a radially outer wall of the second heat exchange portion of the heat exchanger and the peripheral side wall of the containment casing; a fluid outlet passage from the second heat exchange chamber peripherally defined between an axial end of the peripheral side wall of the containment casing and the rear wall of said casing; wherein said first and second heat exchange chamber are separated inside the heat exchanger by a first partition comprising a plate-shaped body; wherein said first and second heat exchange chambers are further separated outside the heat exchanger by a second partition, radially extending between a radially outer wall of the heat exchanger and the peripheral side wall of the containment casing, said second partition being circumferentially extended about the heat exchanger at least at said fluid outlet passage from the second heat exchange chamber and at said first partition so as to define at least one fluid passage between the first and the second collection chambers of the second heat transfer fluid; and wherein the heat exchange cell further comprises a pair of axial separator baffles, axially extending from said second partition up to the rear wall of the containment casing and extending between said radially outer wall of the second heat exchange portion of the heat exchanger and the peripheral side wall of the containment casing, the axial separator baffles being configured to separate a first portion of the second collection chamber of the second heat transfer fluid defined upstream of said axial separator baffles from a second portion of the second collection chamber of the second heat transfer fluid defined downstream of said baffles.

2. The heat exchange cell according to claim 1, wherein said second partition is configured to close at least 90% of a cross-sectional area of the first collection chamber of the second heat transfer fluid defined at a radially outer position with respect to the heat exchanger in the first heat exchange chamber.

3. The heat exchange cell according to claim 1, wherein said second partition has a circumferential extension about the heat exchanger defined by an angle of 25° to 200°.

4. The heat exchange cell according to claim 1, wherein said second partition is configured to allow a peripheral flow of the second heat transfer fluid inside the containment casing towards the second heat exchange chamber along a direction parallel to the peripheral side wall of the casing and adjacent thereto.

5. The heat exchange cell according to claim 1, wherein said second partition is circumferentially extending astride of a longitudinal centerline plane of the fluid outlet passage from the second heat exchange chamber.

6. The heat exchange cell according to claim 1, wherein the first partition comprises an annular crown at least partially interposed between the coils of the tubular duct of the first heat exchange portion of the heat exchanger and the coils of the tubular duct of the second heat exchange portion of the heat exchanger.

7. The heat exchange cell according to claim 6, wherein said second partition radially extends from said annular crown or from the peripheral side wall of the casing.

8. The heat exchange cell according to claim 1, wherein said axial separator baffles are radially extending from said radially outer wall of the second heat exchange portion of the heat exchanger to the peripheral side wall of the casing.

9. The heat exchange cell according to claim 1, wherein said axial separator baffles are fixed to, or integrally formed with, said second partition.

10. The heat exchange cell according to claim 1, wherein said axial separator baffles radially extend from the peripheral side wall of the casing.

11. The heat exchange cell according to claim 1, wherein said axial separator baffles are configured to close at least 90% of a cross-sectional area of the second collection chamber of the second heat transfer fluid externally defined with respect to the heat exchanger in the second heat exchange chamber.

12. The heat exchange cell according to claim 11, wherein said axial separator baffles are axially extending from said second partition up to the rear wall of the containment casing along the entire axial development of the second collection chamber of the second heat transfer fluid defined in the second heat exchange chamber.

13. The heat exchange cell according to claim 1, wherein the second portion of the second collection chamber of the second heat transfer fluid defined downstream of said axial separator baffles is circumferentially extending about the heat exchanger for a portion having an angular extension equal to or less than the circumferential extension of said second partition.

14. The heat exchange cell according to claim 1, wherein said axial separator baffles are axially extending from opposite end edges of said second partition.

15. The heat exchange cell according to claim 1, wherein said axial separator baffles are symmetrically positioned with respect to a centre line plane of said second partition.

16. A heat exchange method between a first heat transfer fluid and a second heat transfer fluid in a heat exchange cell, said heat exchange cell comprising: a containment casing comprising a rear wall and a peripheral side wall, a helically-shaped heat exchanger comprising a tubular duct for the flow of a first heat transfer fluid, the tubular duct being coiled about a longitudinal axis of the helix according to a plurality of coils, said heat exchanger being mounted in said containment casing; a feeding zone of a second heat transfer fluid, intended for the heat exchange with said first heat transfer fluid, defined in the casing coaxially and internally with respect to said heat exchanger; a first heat exchange chamber, defined in said containment casing and in which a first heat exchange portion of the heat exchanger is housed, said first heat exchange chamber comprising a first collection chamber of the second heat transfer fluid externally defined with respect to the heat exchanger between a radially outer wall of the first heat exchange portion of the heat exchanger and the peripheral side wall of the containment casing; a second heat exchange chamber, defined in said containment casing and in which a second heat exchange portion of the heat exchanger is housed, said second heat exchange chamber comprising a second collection chamber of the second heat transfer fluid externally defined with respect to the heat exchanger between a radially outer wall of the second heat exchange portion of the heat exchanger and the peripheral side wall of the containment casing; a fluid outlet passage from the second heat exchange chamber defined in the peripheral side wall of the containment casing near the rear wall of said casing; wherein said first and second heat exchange chamber are separated inside the heat exchanger by a first partition comprising a plate-shaped body; wherein said first and second heat exchange chambers are separated outside the heat exchanger by a second partition, radially extending between the radially outer wall of the heat exchanger and the peripheral side wall of the containment casing, said second partition being circumferentially extending about the heat exchanger at least at said fluid outlet passage from the second heat exchange chamber and at said first partition so as to define a fluid passage between the first and the second collection chambers of the second heat transfer fluid; wherein the method comprises the steps of: feeding the second heat transfer fluid in said feeding zone; carrying out in the first heat exchange chamber a first heat exchange between the second heat transfer fluid and the first heat transfer fluid flowing in the first heat exchange portion of the heat exchanger by flowing through interstices defined between the coils of the tubular duct of the heat exchanger positioned in the first heat exchange chamber; collecting the second heat transfer fluid in said first collection chamber of the second heat transfer fluid defined in the first heat exchange chamber outside the heat exchanger; sending the second heat transfer fluid from said first to said second heat exchange chamber by means of said fluid passage formed between the first collection chamber of the second heat transfer fluid and a first portion of the second collection chamber of the second heat transfer fluid, said first portion of the second collection chamber being externally defined with respect to the heat exchanger in a first portion of the second heat exchange chamber upstream of a pair of axial separator baffles axially extending from said second partition up to the rear wall of the containment casing and extending between said radially outer wall of the second heat exchange portion of the heat exchanger and the peripheral side wall of the containment casing; carrying out in the second heat exchange chamber a second heat exchange between the second heat transfer fluid and the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger by flowing through interstices defined between the coils of the tubular duct of the heat exchanger positioned in said first portion of the second heat exchange chamber; carrying out in the second heat exchange chamber a third heat exchange between the second heat transfer fluid and said first partition by flowing the second heat transfer fluid along a transversal direction through a zone of the second heat exchange chamber defined coaxially and internally with respect to the heat exchanger; carrying out in the second heat exchange chamber a fourth heat exchange between the second heat transfer fluid and the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger by flowing through interstices defined between the coils of the tubular duct of the heat exchanger positioned in a second portion of the second heat exchange chamber defined downstream of said pair of axial separator baffles; and discharging the second heat transfer fluid from the second heat exchange chamber along a direction perpendicular to a longitudinal axis of the heat exchange cell through said fluid outlet passage from the second heat exchange chamber; and wherein said first, second, third and fourth heat exchanges are carried out in series with each other.

17. The heat exchange method according to claim 16, further comprising a step of adjusting the fluid dynamics of the second heat transfer fluid sent towards the second heat exchange chamber by adjusting a circumferential extension of the second partition to adjust an overall cross-sectional area of fluid flow of said passage formed between the radially outer wall of the heat exchanger and the peripheral side wall of the containment casing.

18. The heat exchange method according to claim 16, further comprising a step of adjusting the amount of the second and fourth heat exchange, carried out between the second heat transfer fluid and the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger by flowing through the interstices defined between the coils of the tubular duct of the heat exchanger positioned in said at least one first and, respectively, in said second portion of the second heat exchange chamber, by selecting the circumferential position of said axial separator baffles along the radially outer wall of the heat exchanger.

19. A heating or air-conditioning apparatus comprising a heat exchange cell according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further characteristics and advantages of the present invention will appear more clearly from the following detailed description of a preferred embodiment thereof, made with reference to the appended drawings.

(2) The different characteristics in the individual preferred configurations of the cell may be combined with one another as desired according to the preceding description, should there be advantages specifically resulting from a specific combination.

(3) In such drawings:

(4) FIG. 1 is a perspective view, partially in detached parts and with some details omitted, of a preferred embodiment of a heat exchange cell according to the present invention;

(5) FIGS. 2a and 2b are plan views respectively from above and from below of the heat exchange cell of FIG. 1;

(6) FIG. 3 is a perspective view in detached parts of the heat exchange cell of FIG. 1;

(7) FIG. 4 is a longitudinal sectional view parallel to the axis A-A of the heat exchange cell of FIG. 1 according to the line IV-IV of FIG. 2a;

(8) FIG. 5 is a cross sectional view orthogonal to the axis A-A of the heat exchange cell of FIG. 1 according to the line V-V of FIG. 2b;

(9) FIG. 6 is a perspective view from the rear side of the heat exchange cell of FIG. 1 in partial section and with some details omitted.

DETAILED DESCRIPTION OF CURRENTLY PREFERRED EMBODIMENTS OF THE INVENTION

(10) For the illustration of the drawings, use is made in the following description of identical numerals to indicate construction elements with the same function. Moreover, for clarity of illustration, certain numerical references are not repeated in all the figures.

(11) With reference to the figures, a heat exchange cell is shown, indicated overall with number 10.

(12) In the preferred embodiment illustrated in the figures, the heat exchange cell 10 is a gas-liquid heat exchange cell of the so-called condensation type wherein there is an exchange of heat between a first heat transfer fluid, e.g. comprising water to be heated, and a second heat transfer fluid e.g. comprising hot combustion gases coming from a burner shown by number 20 in the appended figures.

(13) With particular reference to the preferred embodiment illustrated in the figures, the heat exchange cell 10 comprises a containment casing 11 in which a helically-shaped heat exchanger 13 is mounted.

(14) Within the scope of this detailed description and for descriptive simplicity, reference will conventionally be made without any limiting intention to an operating position of the heat exchange cell 10 in which the longitudinal axis A-A of the heat exchanger 13 (that coincides and also represents the longitudinal axis of the cell 10) is horizontal.

(15) Preferably, the containment casing 11 is made of a structural material suitable for this type of use, such as a metal material, for example steel or aluminium, or a high performance and heat resistant plastic material, such as polyphenylene sulfide (PPS), possibly filled with fibres of a functional filler, e.g. glass fibres.

(16) The heat exchanger 13 preferably comprises a tubular duct for the flow of a first heat transfer fluid coiled about a longitudinal axis A-A according to a plurality of coils starting and ending respectively at an inlet opening 13c and outlet opening 13d of the first heat transfer fluid (see FIG. 3).

(17) Preferably, the heat exchanger 13 is made of a metal material with high heat conductivity, such as steel or aluminium.

(18) The inlet openings 13c and outlet openings 13d of the first heat transfer fluid are configured so as to allow respectively the inlet and the outlet of the first heat transfer fluid (water to be heated) into/out of the heat exchanger 13. The inlet and outlet directions of the first heat transfer fluid are indicated in the figures by the arrow L.

(19) In the preferred embodiment illustrated, the tubular duct has a flattened cross section, preferably with a partially oval shape (see FIGS. 3 and 4).

(20) Preferably, the coils of the aforementioned plurality of coils of the tubular duct of the heat exchanger 13 have a flattened cross section whose main axis is substantially perpendicular to the longitudinal axis A-A of the heat exchanger 13.

(21) In a further preferred embodiment (not shown) and for the purpose of satisfying specific application requirements, the main axis of the flattened cross section of the coils of the tubular duct of the heat exchanger 13 can form an acute angle, e.g. comprised between 60° and 87°, with respect to the longitudinal axis A-A of the heat exchanger 13.

(22) Between the flat surfaces of two successive coils of the tubular conduit there is an interstice 13b, preferably with a substantially constant thickness, forming a fluid path for the passage of the second heat transfer fluid along a substantially radial direction (or substantially axial-radial in the event of inclined coils), having a predefined and preferably constant thickness.

(23) For that purpose, the cell 10 is preferably provided with suitable spacer elements, not better represented in the figures, such as protrusions extending from the flat faces of the tubular duct or comb-shaped spacer elements interposed between the aforementioned flat faces and configured to define the interstice 13b between the flat faces of the tubular duct.

(24) Within the scope of the present description and the following claims, the term: “thickness” of the interstice defined between the flat faces of the duct of the heat exchanger 13 means the distance between said faces measured along the perpendicular direction thereto.

(25) Preferably, the helically shaped heat exchanger 13 is mounted inside the containment casing 11 so as to define in such casing a feeding zone 21 of the second heat transfer fluid, in this case comprising the hot combustion gases generated by the burner 20.

(26) Preferably, the feeding zone 21 of the second heat transfer fluid is defined in the containment casing 11 coaxially and internally to the heat exchanger 13.

(27) In this way, it is advantageously possible to have a configuration such as to have inside the heat exchange cell 10 a flow of the second heat transfer fluid that goes from the feeding zone 21 radially (or along the substantially axial-radial direction in the case of inclined coils) towards the outside through the interstices 13b defined between the coils of the helically-shaped heat exchanger 13.

(28) The containment casing 11 of this preferred embodiment of the cell 10 is sealingly closed at the front by a substantially annular front wall, conventional in itself of which for simplicity purposes a first annular element 31 fixed to the peripheral side wall 11c is shown.

(29) Preferably, the front wall comprises a second annular element, not shown, removably sealingly fixed to the first annular element 31 at a peripheral inner edge thereof in a way that is known per se, e.g. through an O-ring (also not shown).

(30) A support plate, conventional per se and also not shown, of burner 20 is fixed onto the front, substantially annular wall of the cell 10 in a removable yet still gas-sealed way.

(31) Preferably, the cell 10 also comprises a substantially annular heat insulating element—again not illustrated for simplicity purposes—facing the feeding zone 21 of the second heat transfer fluid and configured to thermally protect the material of which the front wall of the containment casing 11 is made from the feeding zone 21 of the second heat transfer fluid at high temperature.

(32) In the preferred embodiment illustrated, the containment casing 11 has in particular a substantially cylindrical conformation and comprises two half-shells 11a, 11b, respectively upper and lower, appropriately shaped so as to define a peripheral side wall 11c and a rear wall 11d of the containment casing 11.

(33) In the preferably horizontal operating configuration, the heat exchange cell 10 is in fluid communication with external components (not shown), being part of the apparatus or of the system in which the cell is mounted, through a plurality of openings 12a-12d, preferably formed on the side wall 11c of the containment casing 11 or in further elements associated therewith.

(34) Thus, in the preferred embodiment illustrated, a first opening 12a is configured for the outlet of the second heat transfer fluid from the cell 10 and is preferably formed in an discharge cap 11e of such fluid externally associated with the peripheral side wall 11c of the containment casing 11.

(35) Preferably and as will appear more clearly below, the discharge cap 11e is formed as a single piece in the half-shell 11a (the upper one in the exemplifying horizontal mounting configuration of the cell 10) so as to simplify the manufacturing of the cell 10 by appropriately reducing the number of elements of the cell 10 and simplifying the assembly operations thereof.

(36) In the preferred operating configuration (horizontal) of the preferred embodiment of the heat exchange cell 10 shown in FIG. 1, the outlet opening 12a is preferably positioned so as to have a vertical axis and to be facing upwards.

(37) Second and third openings 12b, 12c are preferably formed at a free end of respective sleeves 28, 29 each of which is appropriately shaped to constitute a respective connector of the heat exchange cell 10 with the hydraulic components of a heating apparatus or system—not shown—in which the cell 10 is installed.

(38) Preferably, the sleeves 28, 29 extend from the peripheral wall 11c of the containment casing 11 and preferably formed as a single piece with the half shell 11b (the lower one in the exemplifying horizontal mounting configuration of the cell 10) of the casing 11.

(39) In this preferred embodiment, the inlet openings 13c and outlet openings 13d of the first heat transfer fluid of the heat exchanger 13 are housed in the sleeves 28, 29 as illustrated in FIG. 3.

(40) The sleeves 28, 29 are therefore preferably configured so as to house the inlet openings 13c and outlet openings 13d of the heat exchanger 13 so as to allow, as described above, respectively the inlet and outlet of the first heat transfer fluid (water to be heated) to/from of the heat exchanger 13.

(41) In the operating configuration of the heat exchange cell 10, the openings 12b, 12c of the sleeves 28, 29 extending from the containment casing 11 are placed respectively to the rear and to the front with respect to each other, with respect to the axial extension of the cell 10 along the longitudinal axis A-A of the helix of the heat exchanger 13, and are facing downwards, in the event of horizontal mounting of the cell 10, so as to facilitate the connection with external components (not shown) of the heating apparatus or system in which the cell 10 is installed.

(42) In the preferred embodiment illustrated of the heat exchange cell 10 and as such cell is of the condensation type, the containment casing 11 is further preferably provided with a fourth opening 12d formed at a free end of a respective sleeve 30 extending from the peripheral wall 11c of the containment casing 11 and preferably formed as a single piece with the half shell 11b (the lower one in the exemplifying horizontal mounting configuration of the cell 10) of the casing 11 (see FIGS. 2b and 5).

(43) The opening 12d is configured for the discharge of the condensate generated during the heat exchange process between the two heat transfer fluids and that is collected in the lower part of the containment casing 11.

(44) The heat exchange cell 10 according to the present invention comprises a first heat exchange chamber 22 defined in the containment casing 11 and in which a first heat exchange portion of the heat exchanger 13 is housed.

(45) The first heat exchange chamber 22 comprises in turn a first collection chamber 15 of the second heat transfer fluid externally defined with respect to the heat exchanger 13 between a radially outer wall 13a of the first heat exchange portion of the heat exchanger 13 and the peripheral side wall 11c of the containment casing 11.

(46) The heat exchange cell 10 according to the present invention further comprises a second heat exchange chamber 26 defined in the containment casing 11 and in which a second heat exchange portion of the heat exchanger 13 is housed.

(47) The second heat exchange chamber 26 comprises a second collection chamber 16 of the second heat transfer fluid externally defined with respect to the heat exchanger 13 between the radially outer wall 13a of the second heat exchange portion of the heat exchanger 13 and the peripheral side wall 11c of the containment casing 11.

(48) In this case, and as the heat exchanger 13 is formed by the helically-shaped tubular duct, the outer wall 13a of its two heat exchange portions is discontinuous, i.e. axially interrupted by the interstices 13b defined between successive coils of the exchanger, and is formed by the radially outer face of the coils of the tubular duct itself.

(49) In the preferred embodiment illustrated, the heat exchange cell 10 further comprises an annular element 36 positioned at the rear wall 11d of the casing 11 and that cooperates in abutment with the heat exchanger 13 so as to guarantee both an effective gas seal and the correct positioning of the heat exchanger 13 inside the casing 11.

(50) In a preferred embodiment, the annular element 36 is extending as a single piece from the rear wall 11d of the casing 11.

(51) Preferably, the annular element 36 extends at least in part in a spiral with substantially the same winding pitch as the coils of the heat exchanger so as to guarantee an effective abutment for the heat exchanger 13.

(52) The first and the second heat exchange chambers 22, 26 are separated inside the heat exchanger 13 by a first separating element 14 comprising a substantially plate-shaped body, which will be described in more detail below.

(53) In the preferred embodiment illustrated, the first separating element 14 comprises an annular crown 14b interposed between the coils of the first heat exchange portion and the coils of the second heat exchange portion of the heat exchanger 13.

(54) Preferably, the annular crown 14b of the first separating element 14 is formed as a single piece with the body of such element.

(55) Preferably, the annular crown 14b of the first separating element 14 is made of a material, preferably metal, with high heat conductivity, such as aluminium or steel.

(56) Preferably, the body of the first separating element 14 centrally defines a seat 14a in which an element 19 made of heat insulating material is housed, so that it faces towards the combustion chamber 21 (feeding zone of the second heat transfer fluid in the cell 10).

(57) Preferably, the heat-insulating element 19 is substantially disc-shaped.

(58) Preferably, the annular crown 14b of the first separating element 14 extends at least partially in a spiral substantially with the same winding pitch as the coils of the heat exchanger 13.

(59) Preferably, the annular crown 14b of the first separating element 14 has a substantially equal thickness to the thickness of the interstice 13b defined between the flat surfaces of two successive coils of the heat exchanger 13.

(60) In a preferred embodiment, the first separating element 14 can comprise a plurality of heat exchange protrusions 23, e.g. substantially pin shaped, extending from a rear face thereof facing towards the rear wall 11d of the casing 11.

(61) These possible heat exchange protrusions 23 are shown in broken lines in FIG. 4.

(62) In this way, it is advantageously possible to increase the exchange surface area of the first separating element 14, therefore increasing the amount of heat exchange between the second heat transfer fluid and the heat exchange portion of the first separating element 14 inside the second heat exchange chamber 26.

(63) The heat exchange cell 10 further comprises a fluid outlet passage 35 from the second collection chamber 16 of the second heat transfer fluid peripherally defined in the peripheral side wall 11c of the containment casing 11 near the rear wall 11d of the casing 11.

(64) More particularly, the fluid outlet passage 35 is preferably peripherally defined between an axial end 11g of the peripheral side wall 11c and the rear wall 11d of the containment casing 11.

(65) In the preferred embodiment illustrated and as will appear more clearly below, the peripheral side wall 11c is formed in part by the half-shell 11a and in part by a plate-shaped element 34 housed in a concealed way in the thickness of the peripheral side wall 11c.

(66) In this preferred embodiment, therefore, the axial end 11g of the peripheral side wall 11c of the containment casing 11 is defined at the rear axial end of the plate-shaped element 34.

(67) In the preferred embodiment illustrated and as can be seen in FIG. 4, the plate shaped element 34 is fixed to the cap 11e through the use of a pin 40 extending from said cap in a corresponding housing seat defined in a projection 41 fixed to, and preferably formed as a single piece with, the plate shaped element 34.

(68) The first and the second heat exchange chamber 22, 26 are further separated outside the heat exchanger 13 by a second separating element 32 extending radially between the radially outer wall 13a of the heat exchanger 13 and the peripheral side wall 11c of the containment casing 11.

(69) Preferably, the second separating element 32 is substantially shaped like a sector of a circular crown.

(70) Preferably, the second separating element 32 is made of a material, preferably metal, with high heat conductivity, such as steel or aluminium.

(71) The second separating element 32 is extending circumferentially about the heat exchanger 13 for a portion having a predefined angular extension at the fluid outlet passage 35 from the second heat exchange chamber 26 so as to prevent the direct passage of most of the second heat transfer fluid towards the passage 35 and define a fluid passage 17 between the first 15 and the second 16 collection chamber of the second heat transfer fluid in a distal zone with respect to such passage 35.

(72) In the horizontal mounting configuration of the cell 10, the fluid passage 17 between the first 15 and the second 16 collection chamber of the second heat transfer fluid is defined in the lower zone of the cell 10.

(73) Preferably, the second separating element 32 is extending circumferentially about the heat exchanger 13 substantially astride of a longitudinal centerline plane of the fluid outlet passage 35 from the second heat exchange chamber 26.

(74) In the preferred embodiment illustrated and for purely exemplifying and non-limiting purposes, the second separating element 32 has a circumferential extension about the heat exchanger 13 defined by an angle, whose vertex is positioned on the longitudinal axis A-A of the heat exchanger 13, equal to about 180°.

(75) Such circumferential extension is shown in FIG. 5 by the angle α which is the angle in fact defined between two half-planes that join the longitudinal axis A-A of the heat exchanger 13 (and of the cell 10) and opposing ends 32a, 32b of the second separating element 32.

(76) Preferably, the second separating element 32 extends between the peripheral side wall 11c of the casing 11 and the heat exchanger 13 at the first separating element 14, more preferably at the annular crown 14b of the first separating element 14.

(77) In the preferred embodiment illustrated, the second separating element 32 is formed as a single piece with the annular crown 14b of the first separating element interposed between the coils of the first heat exchange portion and the coils of the second heat exchange portion of the heat exchanger 13 and extends radially from such annular crown 14b.

(78) In a preferred embodiment and as described above, the second separating element 32 is configured to close at least 90%, more preferably at least 92%, even more preferably at least 95% of the cross-sectional area of the first collection chamber 15 of the second heat transfer fluid defined in a radially outer position to the heat exchanger 13 in the first heat exchange chamber 22.

(79) In a particularly preferred embodiment and as illustrated in the figures, the second separating element 32 is configured to substantially completely close, apart from the inevitable leakages due to the processing tolerances of the various components of the cell 10, the cross section of the first collection chamber 15 of the second heat transfer fluid.

(80) Preferably, the second separating element 32 is configured so as to substantially abut against the peripheral side wall 11c of the containment casing 11, even more preferably with a substantial fluid seal, notwithstanding the inevitable leakages due to the processing tolerances of the containment casing 11, of the second separating element 32 and of the first separating element 14.

(81) The second separating element 32 is therefore configured to prevent a direct passage of the second heat transfer fluid from the first collection chamber 15 towards the fluid outlet passage 35 from the second heat exchange chamber 26 and to conveniently direct such heat transfer fluid towards the passage 17 of fluid between the first 15 and the second 16 collection chamber of the second heat transfer fluid defined in the zone of the cell 10 distal from the fluid outlet passage 35 from the second heat exchange chamber 26 (in the preferred example illustrated in the lower zone of the cell 10).

(82) As described above, the Applicant has experimentally found that by appropriately adjusting the circumferential extension of the second separating element 32 it is possible to achieve the advantageous technical effect of optimizing the fluid dynamics of the second heat transfer fluid—which substantially radially or axially-radially crosses towards the outside of the heat exchanger 13 in the first heat exchange chamber 22—substantially along the whole axial extension of the first heat exchange portion of the heat exchanger 13 and substantially along the whole circumferential extension of this first portion.

(83) In this way, it is advantageously possible to significantly reduce preferential fluid paths, by improving the distribution of the flow of the second heat transfer fluid in crossing the coils of the heat exchanger 13 positioned upstream of the second separating element 32.

(84) In particular, the Applicant has found that the flow rate of the second heat transfer fluid that radially or axially-radially crosses the first heat exchange portion of the heat exchanger 13 passing into the interstice 13b defined between coil and coil can be made substantially constant along the axial section of such first heat exchange portion of the heat exchanger 13 positioned in the first heat exchange chamber 22.

(85) The Applicant also considers that such flow rate is made substantially constant also along the circumferential extension of the first heat exchange portion of the heat exchanger 13 so that the second heat transfer fluid transits uniformly in the first annular collection chamber 15 along the circumferential extension of such first heat exchange portion, significantly reducing the presence of dead zones not travelled by the fluid in the first collection chamber 15 of the second heat transfer fluid.

(86) The Applicant has also experimentally found that by appropriately defining the circumferential extension of the second separating element 32 it is also possible to optimize the fluid dynamics of the second heat transfer fluid by flowing through the first collection chamber 15 in the first heat exchange chamber 22 of the cell 10 defined upstream of the second separating element 32 and by flowing through the passage 17 towards the second collection chamber 16 defined in the second heat exchange chamber 26.

(87) In the preferred embodiment illustrated in the figures, the cross-sectional area of fluid flow 17 defined between the first 15 and the second 16 collection chamber of the second heat transfer fluid by the second separating element 32 is in particular uniformly distributed along the peripheral side wall 11c of the containment casing 11 (see FIG. 5).

(88) Preferably, the second separating element 32 is removably fixed to the plate-shaped element 34 that forms part of the peripheral side wall 11c of the casing 11 through means that are conventional per se, such as a bolt 42 that connects a fin 43 extending axially from the second separating element 32 to the plate-shaped element 34.

(89) Preferably, the second collection chamber 16 of the second heat transfer fluid is in fluid connection with a third collection chamber 18 of the second heat transfer fluid defined downstream of the fluid outlet passage 35.

(90) More particularly, the third collection chamber 18 is in fluid connection with the fluid outlet passage 35 from the second collection chamber 16 and with the outlet opening 12a of the second heat transfer fluid of the cell 10, defined downstream of the third collection chamber 18, as shown in FIG. 4.

(91) The third collection chamber 18 of the second heat transfer fluid is defined in the cap 11e, which extends from the peripheral side wall 11c of the casing radially towards the outside of the casing 11, and in which the outlet opening 12a is realized.

(92) In this preferred embodiment of the cell 10, therefore, the cap 11e is positioned downstream of the fluid outlet passage 35 from the second collection chamber 16 and from the second heat exchange chamber 26.

(93) More details on the configuration of the heat exchange cell 10 of this preferred embodiment and, in particular, of the peripheral side wall 11c, of the first separating element 14, of the second and third collection chambers 16, 18 and of the fluid outlet passage 35 can be found in FIGS. 3, 4 and 6.

(94) In the preferred embodiment illustrated in the figures, the cap 11e is realized at an inner opening formed in the thickness of the peripheral side wall 11c of the casing 11 and intended to house with a shape coupling the plate-shaped element 34.

(95) In such preferred embodiment, the cap 11e is realized in axis with the centerline plane of the heat exchange cell 10 and, as described above, is preferably formed as a single piece with the peripheral side wall 11c of the casing 11.

(96) In an alternative preferred embodiment, not illustrated, the cap Ile can comprise an independent element, anchored to the peripheral side wall 11c of the casing 11 through appropriate fixing means.

(97) According to the invention, the heat exchange cell 10 further comprises a pair of axial separator baffles 24a, 24b extending axially between the second separating element 32 and the rear wall 11d of the containment casing 11.

(98) The axial separator baffles 24a, 24b are in particular configured to separate a first portion 16a of the second collection chamber 16 of the second heat transfer fluid defined upstream of the axial separator baffles 24a, 24b of a second portion 16b of the second collection chamber 16 of the second heat transfer fluid defined downstream of the partition walls 24a, 24b.

(99) In the preferred embodiment illustrated, the axial separator baffles 24a, 24b are radially extending between the radially outer wall 13a of the second heat exchange portion of the heat exchanger 13 and the peripheral side wall 11c of the casing 11 of the cell 10.

(100) In this way, it is advantageously possible to achieve in a structurally simple way the desired configuration of the partition walls 24a, 24b adapted to suitably subdivide the second heat exchange chamber 26 and to separate from each other the first and the second portion of the second collection chamber 16 of the second heat transfer fluid defined respectively upstream and downstream of the axial separator baffles 24a, 24b.

(101) In the preferred embodiment illustrated, the axial separator baffles 24a, 24b are formed as a single piece with the second separating element 32.

(102) In this preferred embodiment and as can be appreciated from FIG. 3, therefore, the first separating element 14, the second separating element 32 and the axial separator baffles 24a, 24b are formed as a single piece with each other so as to advantageously reduce the number of elements that compose the heat exchange cell 10.

(103) Specifically, the axial separator baffles 24a, 24b extend as a single piece from the opposing ends 32a, 32b of the second separating element 32 (see FIGS. 5 and 6).

(104) In this case, it is advantageously possible to achieve structural continuity between the second separating element 32 and the axial separator baffles 24a, 24b so as to prevent possible leakages at the interface between them along a circumferential direction in a radially outer position to the second heat exchange portion of the heat exchanger 13.

(105) Preferably, the second separating element 32 and the axial separator baffles 24a, 24b are made of a metal that is a good heat conductor, preferably steel or aluminium.

(106) Preferably, the second separating element 32 and the axial separator baffles 24a, 24b are made of sheet metal, e.g. steel, relatively thin, e.g. having a thickness substantially equal to the thickness of the interstice 13b defined between the flat surfaces of two successive coils of the heat exchanger 13.

(107) In a completely exemplifying way, the second separating element 32 and the axial separator baffles 24a, 24b may have a thickness preferably comprised between about 0.6 and about 1.0 mm.

(108) In the preferred embodiment illustrated, and as the second separating element 32 and the axial separator baffles 24a, 24b are made of relatively thin sheet metal, it is possible to envisage, in a completely exemplifying and non-limiting way, the removable fixing to the side wall 11c of the casing 11, realized in a way that is known per se, e.g. through one or more bolts, all indicated with reference number 44.

(109) Preferably, the second separating element 32 is provided for this purpose with one or more further fins 43 extending axially from the second separating element 32 for fixing to the side wall 11c of the casing 11 (see FIGS. 3, 5 and 6).

(110) In the preferred embodiment illustrated, the axial separator baffles 24a, 24b are also symmetrically positioned with respect to a centerline plane of the second separating element 32.

(111) In this way, it is advantageously possible to have a balanced and symmetrical distribution of the flow of the second heat transfer fluid in passing through the first portion 16a of the second collection chamber 16 of the second heat transfer fluid and in the subsequent passing through of the coils of the heat exchanger 13 positioned immediately downstream of such first portion 16a.

(112) In a preferred embodiment and as described above, the axial separator baffles 24a, 24b are configured to close at least 90%, more preferably at least 92%, even more preferably at least 95% of the cross section of the second collection chamber 16 of the second heat transfer fluid defined in a radially outer position to the heat exchanger 13 in the second heat exchange chamber 26.

(113) In a particularly preferred embodiment and as illustrated in the figures, the axial separator baffles 24a, 24b are configured to substantially completely close, apart from the inevitable leakages due to the processing tolerances of the various components of the cell 10, the cross section of the second collection chamber 16 of the second heat transfer fluid.

(114) In the preferred embodiment illustrated, therefore, the axial separator baffles 24a, 24b are axially extending between the second separating element 32 and the rear wall 11d of the containment casing 11 of the cell 10 substantially along the entire axial extension of the second collection chamber 16 of the second heat transfer fluid defined in the second heat exchange chamber 26.

(115) More preferably, the axial separator baffles 24a, 24b extend in the second collection chamber 16 of the second heat transfer fluid so as to substantially abut against the rear wall 11d of the containment casing 11 of the cell 10.

(116) In this way and as disclosed above, it is advantageously possible to substantially limit and, more preferably, substantially prevent (still notwithstanding the inevitable leakages due to processing tolerances), the fluid communication between the first portion 16a and the second portion 16b of the second collection chamber 16 of the second heat transfer fluid defined respectively upstream and downstream of the axial separator baffles 24a, 24b.

(117) In this way, it is advantageously possible to appropriately close the second portion 16b of the second collection chamber 16 of the second heat transfer fluid defined externally to the second heat exchange portion of the heat exchanger 13 downstream of the axial separator baffles 24a, 24b.

(118) In this way, it is also advantageously possible to substantially divert the whole flow of second heat transfer fluid towards the coils of the heat exchanger 13 positioned in the first portion of the second heat exchange chamber 26 defined upstream of the axial separator baffles 24a, 24b.

(119) In this way, the cell 10 achieves an advantageous increase in the amount of the heat exchange between the second heat transfer fluid and: i) the coils of the heat exchanger 13 positioned in the first portion of the second heat exchange chamber 26 defined upstream of the axial separator baffles 24a, 24b, ii) the first separating element 14 (or better the rear face thereof) positioned inside the heat exchanger 13 in the second heat exchange chamber 26, and iii) the coils of the heat exchanger 13 positioned in the second portion of the second heat exchange chamber 26 defined downstream of the axial separator baffles 24a, 24b.

(120) All this happens with an increase in seasonal space heating energy efficiency is of the cell, in particular the efficiency in active mode ηson and the quantity of latent condensation heat of the combustion gases recovered in the second heat exchange chamber 26.

(121) In the preferred embodiment illustrated, the second portion 16b of the second collection chamber 16 of the second heat transfer fluid defined downstream of the axial separator baffles 24a; 24b is circumferentially extending about the heat exchanger 13 for a portion having an angular extension equal to the circumferential extension of the second separating element 32.

(122) Advantageously, this preferred characteristic is conveniently achieved thanks to the fact that the axial separator baffles 24a, 24b extend axially from the opposing ends 32a, 32b of the second separating element 32.

(123) In the preferred embodiment illustrated and thanks to the configuration of the second separating element 32 and of the axial separator baffles 24a, 24b, cooperating with each other in subdividing, preferably in a substantially gas-tight manner (save for, as mentioned, the inevitable leakages due to processing tolerances), the second heat exchange chamber 26 of the cell 10, it is therefore advantageously possible to vary (and determine during the manufacturing of the heat exchange cell) the circumferential extension of the first and of the second portion 16a, 16b of the second collection chamber 16 of the second heat transfer fluid as a function of the fluid dynamic characteristics and the heat exchange characteristics that are to be obtained in the second heat exchange chamber 26 of the cell 10.

(124) Thus, for example, it is possible to vary the circumferential extension of the first and of the second portion 16a, 16b of the second collection chamber 16 of the second heat transfer fluid by varying the circumferential extension of the second separating element 32 and positioning the axial separator baffles 24a, 24b appropriately along the circumferential extension of the second separating element 32.

(125) A preferred embodiment of a heat exchange method according to the invention that can be actuated with the cell 10 previously described will now be described, with particular reference to FIGS. 1-6.

(126) In an initial step of the method, the second heat transfer fluid is fed in the feeding zone 21, e.g. through the generation of combustion gases by the burner 20 positioned in such area (combustion chamber 21).

(127) In a subsequent step, the method comprises the step of carrying out in the first heat exchange chamber 22 a first heat exchange between the second heat transfer fluid (combustion gas) and the first heat transfer fluid (heating water) flowing in the first heat exchange portion of the heat exchanger 13 by flowing through the coils of the heat exchanger 13 positioned in the first heat exchange chamber 22.

(128) In this step, the second heat exchange fluid (combustion gas) crosses the coils of the heat exchanger 13 along a substantially radial direction (or axial-radial in the case of coils inclined with respect to the longitudinal axis A-A of the heat exchanger 13) passing through the interstices 13b formed between two successive coils of the heat exchanger 13.

(129) During such passage, there is an exchange of heat between the second heat transfer fluid and the first heat transfer fluid circulating in the first heat exchange portion of the heat exchanger 13 preferably in counter current with respect to the flow direction of the combustion gases.

(130) For better understanding of the method according to the invention, the flow of the second heat transfer fluid (combustion gas) inside the cell 10 is shown in the figures by the arrows F.

(131) In a subsequent step, the method comprises collecting the second heat transfer fluid (combustion gas) in the first collection chamber 15 defined in the first heat exchange chamber 22 of the cell 10 externally to the heat exchanger 13.

(132) In a subsequent step, the method comprises sending the second heat transfer fluid collected in the first collection chamber 15 into the second heat collection chamber 16 defined in the second heat exchange chamber 26 of the cell 10, substantially parallel to the peripheral side wall 11c of the casing 11 and in proximity thereto.

(133) According to the method that can be actuated through the preferred embodiment of the cell 10 illustrated in the figures, this step of sending the combustion gases (second heat transfer fluid) is actuated through the passage 17 formed inside the casing 11 of the cell 10 by the second separating partition wall 32 between the first collection chamber 15 of the second heat transfer fluid and the first portion 16a of the second collection chamber 16 of the second heat transfer fluid.

(134) As described above, such first portion 16a of the second collection chamber 16 is defined externally to the heat exchanger 13 in a corresponding first portion of the second heat exchange chamber 26 upstream of the axial separator baffles 24a, 24b.

(135) In a subsequent step, the method according to the invention comprises carrying out in the second heat exchange chamber 26 a second heat exchange between the second heat transfer fluid and the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger 13 by passing through the coils of the heat exchanger 13 positioned in the first portion of the second heat exchange chamber 26.

(136) Advantageously, this second heat exchange takes place between the substantial totality of the flow of the second heat transfer fluid that is directed towards the coils of the heat exchanger 13 positioned in the first portion of the second heat exchange chamber 26 by the second separating element 32 and by the axial separator baffles 24a, 24b.

(137) In a subsequent step, the method according to the invention comprises carrying out in the second heat exchange chamber 26 a third heat exchange between the second heat transfer fluid and the first separating element 14 by passing through in a substantially transversal direction of the zone of the second heat exchange chamber 26 defined inside the heat exchanger 13.

(138) Advantageously, this third heat exchange allows the heat to be effectively removed from the first separating element 14 transferring it to the second heat transfer fluid previously cooled while crossing the coils of the heat exchanger 13 positioned in the first portion of the second heat exchange chamber 26.

(139) In a subsequent step, the method according to the invention comprises carrying out in the second heat exchange chamber 26 a fourth heat exchange between the second heat transfer fluid and the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger 13 by flowing through the coils of the heat exchanger 13 positioned in the second portion of the second heat exchange chamber 26 defined downstream of the axial separator baffles 24a, 24b.

(140) Advantageously, this fourth heat exchange allows losses to be substantially reduced towards the chimney of the residual heat possessed by the second heat transfer fluid that has passed through in a substantially transversal direction the zone of the second heat exchange chamber 26 defined inside the heat exchanger 13.

(141) Indeed, this residual heat is substantially completely yielded to the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger 13 positioned downstream of the axial separator baffles 24a, 24b.

(142) As described above, the Applicant has experimentally found a significant increase in the performance of the heat exchange cell 10 in the recovery of latent condensation heat of the combustion gases.

(143) In particular and as described above, the Applicant has experimentally found, in the aforementioned prolonged working tests in relation to 10 years of operation, that the recovery of the latent condensation heat of the combustion gases in the second heat exchange chamber 26 reaches a level such as to obtain a flow of condensate able to perform an effective “washing” action on the coils of the heat exchanger 13 located in the lower part of the second heat exchange chamber 26, i.e. the one particularly subject to possible incrustation accumulation.

(144) At the end of the performed experimental tests, indeed, the Applicant was able to verify that the surface of the coils of the heat exchanger 13 located in the second heat exchange chamber 26 were totally free from incrustations or deposits of unburned particles.

(145) In a subsequent step, the method according to the invention comprises discharging the second heat transfer fluid from the second heat exchange chamber 26 along a direction substantially perpendicular to the longitudinal axis A-A of the heat exchange cell 10 through the fluid outlet passage 35 from the second heat exchange chamber 26.

(146) Advantageously, the cell 10 and the heat exchange method that can be actuated through such cell allow an increase—thanks to the formation of a uniform flow directed transversally in the second heat exchange chamber 26—of the heat exchange efficiency of the cell and in particular—when desired—an increase in the condensation effect thanks to improved heat exchange between the second heat transfer fluid and all the elements of the cell 10 present in the second heat exchange chamber 26 and in a heat exchange relation with such fluid (coils of the second heat exchange portion of the heat exchanger 13 and rear wall of the first separating element 14).

(147) As described above, the Applicant has experimentally found, in the aforementioned prolonged working tests, that the configuration of the second heat exchange chamber 26 of the cell 10 according to the invention also allows, very advantageously, its performance characteristics to be kept substantially unaltered over time.

(148) Indeed, the configuration of the second heat exchange chamber 26 of the heat exchange cell 10 according to the invention allows compensation during the operation of the cell 10 for a progressive reduction in heat exchanged in the first heat exchange chamber 22 with a corresponding progressive increase in heat exchanged in the second heat exchange chamber 26 of the cell 10.

(149) This is thanks to the fact that, as described above, the second heat transfer fluid is forced to cross in series and along a substantially transversal direction the coils of the second heat exchange portion of the heat exchanger 13 positioned upstream of the axial separator baffles 24a, 24b, the zone of the second heat exchange chamber 26 defined inside the heat exchanger 13 and the coils of the second heat exchange portion of the heat exchanger located downstream of the axial separator baffles 24a, 24b.

(150) In this way, the heat exchange cell 10 according to the invention is advantageously able to substantially completely recover in the second heat exchange chamber 26 any heat not exchanged in the first heat exchange chamber 22 due to a gradual deposit of incrustations on the internal part of the heat exchanger 13.

(151) In a preferred embodiment, the method comprises adjusting the fluid dynamics of the second heat transfer fluid sent towards the second heat exchange chamber 26 by adjusting the overall cross-sectional area of fluid flow of the passage 17 formed between the radially outer wall 13a of the heat exchanger 13 and the peripheral side wall 11c of the containment casing 11 of the cell 10.

(152) As disclosed above, this adjustment is realized by appropriately defining the circumferential extension of the second separating element 32.

(153) In a preferred embodiment, the method comprises adjusting the amount of the second and of the fourth heat exchange, carried out between the second heat transfer fluid and the first heat transfer fluid flowing in the second heat exchange portion of the heat exchanger 13 by passing through the coils of the heat exchanger 13 positioned in the first and, respectively, in the second portion of the second heat exchange chamber 26.

(154) This adjustment step is preferably advantageously obtained by adjusting the circumferential position of said axial separator baffles 24a; 24b along the radially outer wall 13a of the heat exchanger 13.

(155) In a preferred embodiment, the method comprises increasing the amount of the second heat exchange carried out in the second zone of the second heat exchange chamber 26 through the heat exchange protrusions 23 described above.

(156) The Applicant has experimentally found that thanks to the advantageous characteristics of the cell 10 and of the method described above, the amount of heat exchange that takes place in the second heat exchange chamber 26 of the cell 10 can be optimized so as to increase the seasonal space heating energy efficiency is of the cell 10, and in particular the efficiency in active mode ηson, having a much larger preponderant impact on the determination of the seasonal energy efficiency is of the cell, with respect to cell configurations of the prior art.