Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
  • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
  • F24H1/34—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water chamber arranged adjacent to the combustion chamber or chambers, e.g. above or at side
  • F24H1/36—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water chamber arranged adjacent to the combustion chamber or chambers, e.g. above or at side the water chamber including one or more fire tubes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D9/00—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D9/0081—Heat-exchange apparatus having stationary plate-like or laminated conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for one heat-exchange medium being formed by a single plate-like element ; the conduits for one heat-exchange medium being integrated in one single plate-like element
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
  • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F7/00—Elements not covered by group F28F1/00, F28F3/00 or F28F5/00
  • F28F7/02—Blocks traversed by passages for heat-exchange media
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
  • F28F9/02—Header boxes; End plates
  • F28F9/026—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits
  • F28F9/0282—Header boxes; End plates with static flow control means, e.g. with means for uniformly distributing heat exchange media into conduits by varying the geometry of conduit ends, e.g. by using inserts or attachments for modifying the pattern of flow at the conduit inlet or outlet
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D7/0041—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for only one medium being tubes having parts touching each other or tubes assembled in panel form
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
  • F28D7/0058—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits for only one medium being tubes having different orientations to each other or crossing the conduit for the other heat exchange medium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
  • F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
  • F28F21/081—Heat exchange elements made from metals or metal alloys
  • F28F21/084—Heat exchange elements made from metals or metal alloys from aluminium or aluminium alloys

Definitions

• the present invention relates to a heat exchanger, in particular, to a heat exchanger for use in condensing boilers.
• the heat exchanger which is the main object of the present invention, is of advantageous, but not exclusive application in the realization of condensing boilers, to which the following description will make explicit reference without loss of generality.
• the present invention belongs to the heat exchangers referred to in paragraph ( 4 ) .
• the solution to the present invention is based on the technology of aluminum die casting, the less expensive sand casting technology, to obtain a heat exchanger with a drastic reduction in the number of needed components and therefore with a significant reduction of costs.
• a heat exchanger is provided as claimed in claim 1, and a condensing boiler comprising the aforementioned heat exchanger as defined in claim 10.
• FIG. 1 illustrates a three-dimensional view of a first embodiment of a heat exchanger according to the present invention inserted in a condensing boiler;
• FIG. 2 shows an exploded diagram of condensing boilers in Figure 1;
• FIG. 3 shows an enlarged detail of the heat exchanger illustrated in figures 1, 2 taken from a first point of observation;
• FIG. 5 shows a front view of the detail shown in Figures
• FIG. 7 shows a three dimensional view of a section of certain details comprised in the condensing boiler shown in Figure 1;
• FIG. 8 shows a plurality of elements included within the heat exchanger shown in Figure 1;
• FIG. 9 shows a three dimensional view of a second embodiment of a heat exchanger according to the present invention inserted within a condensing boiler.
• FIG. 10 shows an exploded view of the condensing boiler shown in Figure 9.
• FIG. 1 indicated as a whole with 100, is shown a condensing boiler comprising a heat exchanger 10, made according to the teaching of the present invention, on which is mounted a burner 50 of a traditional type.
• the heat exchanger 10 comprises, in turn, three essential parts:
• main body 11 an element of direct exchange, the so-called main body 11;
• inserts 12 a series of elements of indirect exchange, called inserts 12, and
• a container 13 which, as will be seen, contains within it both the main body 11, and the inserts 12; it should be noted, also, that the container 13 is provided with a cold water inlet fitting 13a and a hot water outlet fitting 13b ( Figures 1, 2) .
• the container 13 has an axially symmetric shape that allows it to withstand the internal pressure of the water with minimal mechanical stress.
• the main body 11 forms the element of heat exchange between exhaust gas and water. Said main body 11 preferably, but not necessarily, is obtained in a single piece by only one aluminum die casting process.
• the exhaust gases are generated during the combustion process, which takes place in a known way in the burner 50 by way of a process of combustion of the air/fuel gas forced within the burner 50 itself by a fan (not shown) .
• the container 13 contains, together with the main body 11, the water in the hydraulic system and collects the exhaust gases from the burner 50.
• the main body 11 comprises a combustion chamber 14 substantially cylindrical and at least partially finned. From the bottom of the combustion chamber 14 a series of channels 15 downwardly branch off for the passage of exhaust gases ending at a terminal flange 16 parallel to the bottom of the combustion chamber 14. The flow of exhaust gases in the channels 15 takes place according to a first direction identified by an arrow (Fl) . In this case, the direction (Fl) is vertical.
• each channel 15 is defined by a pair of vertical baffles 17a, 17b, substantially parallel to each other, which in plan-view drawing and in the case of the embodiment shown in Figures 1-8, are "chords", parallel to each other, of a circumference (CIR) that encloses the main body 11.
• each pair of vertical baffles 17b, 17a also defines a duct 18 closed at the top and at the bottom by parallel walls, respectively, at the bottom of the combustion chamber 14 and the end flange 16.
• the exhaust gas channels 15 alternate with water ducts 18 to be heated. Note also that while the channels 15 of the exhaust gases do not communicate with each other but each with the output 13c of the container 13, the water ducts 18 are in hydraulic communication with each other (see below) .
• the main body 11 there are provided also two vertical baffles 20, which define, together with horizontal baffles 19 and the inner wall (SUPI) of the container 13 (see also Figures 6, 7) , areas 21a, 21b, 21c, 21d within which occurs the passage of water which is forced to flow through said areas 21a, 21b, 21c, 21d in directions perpendicular to the channels 15 crossed through by exhaust gases (see below).
• the water flows through the areas 21a, 21b, 21c, 21d in the directions (F2), substantially horizontal and perpendicular to the abovementioned direction (Fl) of the exhaust gases.
• both the horizontal baffles 19 and the vertical baffles 20 are provided with seals 19a, respectively, 20a, which, when the main body 11 is mounted within the container 13, rest upon the inner surface (SUPI) of the container 13 thereof defining the regions in which there can be no passage of water between an area 21a, 21b, 21c, 21d and the other.
• zones 21a, 21b, 21c, 21d constitute a sort of overlapping "planes" jointed together, two by two, by the recesses 22a, 22b, 22c, which, therefore, represent a sort of "stairs" between one "plane” and the other.
• the ducts 18 as a whole provides an essentially horizontal labyrinth path for the water, except for the vertical passages consisting in transit recesses 22a, 22b, 22c from one area 21a, 21b, 21c, 21d to the other.
• Figure 3 can be seen a solution having the area 21a divided into four ducts 18 flowed by water in parallel in one direction, followed by three ducts 18 flowed in parallel in the opposite direction.
• the area 21b, immediately above the area 21a is divided into ducts 18 initially flowed in parallel and then in series.
• the area 21c, below the combustion chamber 14, comprises a plurality of ducts 18 flowed by water only in series .
• partition elements 30 are provided with an adequate number of calibrated circular holes 31 (or calibrated slots) whose dimensions are determined so as to obtain water flows evenly distributed among the single ducts 18 affected by the flow of water in the same direction.
• the partition element 30 with relative calibrated circular holes 31 can be obtained as a single piece with the main body 11 during the same die casting operation.
• the main body 11 is held in position with respect to the container 13 by an appropriate number of screws (not shown) that fix it to the latter.
• the inner surfaces of channels 15 flowed by the exhaust gases are corrugated for increasing the exchange surface at the side of the exhaust gases for a given size of each single channel 15.
• Each insert 12 presents dimensions and shapes so as to enable a proper coupling with the respective channel 15. Moreover, as shown in Figure 2, a first insert 12 of each pair is inserted in the respective channel 15 from above, while an identical second insert 12, which completes the pair, is inserted in the same channel 15 from below.
• Each insert 12 presents upon its surface an adequate number of protruding fins 41 (Figure 8), compared to the corrugated surface of the adjacent channel 15 in which it is inserted in order to come into contact with the corresponding corrugated area of the channel 15 and transmit by conduction the heat collected from the exhaust gases.
• the amount of heat is increased transmitted by conduction between the inserts 12, which heat up, and the surfaces of the ducts 18 on which the projecting wings 41 are lying;
• heat transfer parameters are also improved by convection between the exhaust gases themselves in transit, that due to the shape of the fins 41 themselves, are pushed towards the walls of the ducts 18.
• the cold water enters the boiler 100 through the inlet fitting 13a housed on the container 13 in the most distant area 21a from the combustion chamber 1, the water then flows in parallel a first part of the ducts 18 of said area 21a, passing onto the next block of ducts 18 in the same area through a space (of the type (SP) ) cleared by the end of the channel 15 of the exhaust gas and the inner surface (SUPI) of the container 13; flows in parallel along these latter ducts 18 of the same area 21a in the opposite direction to the previous; the water then passes through the following area 21b through the recess 22a ( Figure 3) housed in the horizontal baffles 19 that separates the two adjacent areas 21a, 21b; once all paths of this area 21b are flowed through, the water rises to the next area 21c, positioned at the bottom of the combustion chamber 13, by way of the recess 22c ( Figure 4) correspondingly obtained in the first duct 18 of said area 21c affected by the flow of water.
• a space of the type (SP
• a mixture of air/gas fuel enters the combustion chamber 14 exiting from the burner 50, feeds the combustion process previously activated and is transformed into combustion products.
• the exhaust gases give off heat to the finned walls of the combustion chamber 14 and are forwarded into the gaps existing between the corrugated walls of the channels 15 of the heat exchanger 10 and the corresponding inserts 12 further exchanging heat to reach the dew-point temperature equivalent to the atmospheric pressure and then condensing the vapor fraction contained therein; finally the exhaust gases exit from the gaps of the channels 15 collecting in a compartment 42 ( Figure 7) below the main body 11 to be sent, finally, outside the boiler 100 by way of the outlet 13c, while the condensation that has formed in the compartment 42 is evacuated through an appropriate duct (not shown) .
• the present invention can be applied to main bodies having perimeters (PR) of any shape (circular, elliptical, square, rectangular, etc.).
• the inner surface of the container 13* is free of recesses and sealing gaskets, needed to contain the water and to divert the flow of water inside, are assembled on the main body 11* substantially in the same way seen for the first embodiment illustrated in Figures 1-8.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Geometry (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

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• 2010
  • 2010-10-21 IT ITBO2010A000636A patent/IT1402362B1/it active
• 2011
  • 2011-10-21 WO PCT/IB2011/054726 patent/WO2012052977A2/en active Application Filing
  • 2011-10-21 EP EP11804795.0A patent/EP2630412A2/de not_active Withdrawn

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