EP2038586A2

EP2038586A2 - Heat exchanger of modular structure and method for the formation thereof

Info

Publication number: EP2038586A2
Application number: EP06783828A
Authority: EP
Inventors: Jan Hubertus Deckers
Original assignee: Bekaert Combustion Technology BV
Current assignee: Bekaert Combustion Technology BV
Priority date: 2006-07-07
Filing date: 2006-07-07
Publication date: 2009-03-25
Also published as: WO2008004855A2; WO2008004855A3

Abstract

A heat exchanger, comprising a series of members, which members are intercoupled, wherein: the members each comprise a burner chamber with a burner position, a heat exchange area, a flue gas feed-through, a flue gas exhaust and a water-carrying channel with an inlet and an outlet; the members are each arranged for comprising a burner which at least partly extends in the respective burner chamber; the burner chambers of the juxtaposed members are in open connection to one another; and a first, second and third channel are provided, which interconnect the inlets, the outlets and the gas/air inlets of the different members, respectively.

Description

Title: Heat exchanger of modular structure and method for the formation thereof

The invention relates to a heat exchanger. The invention particularly relates to a gas-fired heating apparatus for space heating and/or tap water heating, provided with such a heat exchanger.

Heating apparatuses are known from practice and are used to provide, for instance, a space heating, such as central heating, or for heating tap water, for instance in a boiler. These functions may also be combined in one heating apparatus. With existing heating apparatuses, a heat exchanger is preferably cast in one piece, for instance from light metal. Such a heat exchanger comprises a burner chamber with a heating exchange area contiguous thereto. From the heat exchange area, further, a flue gas exhaust channel extends.

Such a heating apparatus has the advantage that is can be built relatively compactly, at least in proportion to the desired capacity. However, a drawback of such a heating apparatus is that the heat exchanger will always be geared to a certain prefixed capacity. For a supplier of such heating apparatuses, this means that a series of different heat exchangers will need to be cast in order to be able to supply heating apparatuses with different capacities. This is expensive and logistically inconvenient. In addition, the molds to be used for this are relatively large and consequently expensive.

The invention contemplates providing a heat exchanger which has a simple structure and can simply be adjusted to a desired or required capacity.

The invention particularly contemplates providing a heat exchanger which can be built up with relatively simple means. It is a further object of the invention to provide a heat exchanger which has a high efficiency during use.

The invention further contemplates providing a heat exchanger which can be designed so as to condense. It is a still further object of the invention to provide a heat exchanger which can have a relatively compact and light design, can simply be connected and operated and which has a good ratio of weight to capacity.

At least a number of these and other objects are achieved with a heat exchanger according to the invention. In an advantageous embodiment, a heat exchanger according to the invention is characterized by the measures according to claim 1.

With a heat exchanger according to claim 1, a heat exchanger is built up from a series of members, each shaped such that it can be used as a heat exchanger by itself. Each member comprises inter alia a burner chamber with a burner position in which a burner can be placed, a water-carrying channel and a flue. A series of such members can also be intercoupled as desired, while also one such member can be used as a heat exchanger. Since each member has an inlet and outlet for the water channel, as well as a burner position, and the members are preferably identical, a first, second and third channel can simply be provided for connecting the inlets, the burner positions and the outlets, respectively. These channels can extend against the outside along the members. Thus, a particularly advantageous, simple construction is obtained.

The first, second and third channel can simply be adjusted for length to the number of members provided in the heat exchanger. The water- carrying channels of the different members preferably form parallel heating paths whereby individual heating is obtained in the members.

With a heat exchanger according to the invention, preferably the burner chambers of the different members are interconnected in that they are open on both sides. Thus, one continuous burner chamber is created with a burner therein in each member. Both ends of such a heat exchanger are preferably closed off by a closing plate, while, in one of the closing plates, an igniter may be provided for the different burners. If the heat exchanger is only built up from one element or member, it is closed off by a closing plate on both sides.

In an advantageous embodiment, the first, second and third channel are provided in a profile, in particular an extruded profile. Such a profile has the advantage that it is simple to manufacture and can, in addition, simply be geared to the length of the series of members. Here, it is preferred that a fourth channel is provided as well, for connection of the flue gas exhausts, which fourth channel can also be included in above-mentioned profile.

With a heat exchanger according to the invention, seen in top plan view, the members are preferably substantially rectangular, such that they can connect to one another and/or a closing plate by two opposite flat sides. The top side of the members is preferably substantially flat, at least such that, of the inlet, burner position, outlet and flue gas exhaust, at least two, more in particular three and preferably four are located in one plane, i.e. level with one another. More generally, it is preferred that the inlets, burner positions, outlets and flue gas exhausts are placed with respect to one another such that straight first, second, third and/or fourth channels can be provided along them for connection thereto. This allows the channels to be made and connected more simply.

It is further preferred that, in each member, heat-transferring surface-increasing elements such as cams and/or ribs are provided. Thus, heat from combustion gases can more adequately be transferred to water in the or each water-carrying channel in a respective member. Preferably, such elements are particularly provided in a heat exchange area and/or in the flue gas feed-through, where the combustion gases are relatively warm compared to the water flowing along them. In a special embodiment, a part of the water-carrying channel, in particular a part extending from or from near the inlet, extends so as to be included between the heat exchange area and/or the burner chamber on the one side and the flue gas feed-through on the other side. As a result, residual heat present in the flue gases can be transferred to the relatively cool water to be supplied. As a result, the efficiency of the heat exchanger is increased still further during use. Heat- transferring surface -increasing elements may be provided against the wall of the flue gas exhaust, on the side thereof proximal to the above-mentioned part of the water-carrying channel. The or each water-carrying channel preferably extends along at least two sides of the burner chamber and at least two sides of the heat exchange area. As a result, the heat transfer from the burner and the flue gases to the water is still further improved. In addition, the burner chamber is efficiently cooled thereby. With a heat exchanger according to the invention, preferably, use is made of relatively small burners, for instance with a surface of less than 2000 mm², more in particular less than 100 mm². Particularly advantageous is a burner with a substantially round burner cover, for instance with a diameter of 25 to 30 mm, the burner preferably having a height which is also relatively small, for instance less than 30 mm, more in particular less than 20 mm, and preferably an average height between about 10 and 15 mm. Such burners are, for instance, known by the name of Furinit. Such relatively small burners have the advantage that they require little space for building in and can develop sufficient heat. The burner chamber preferably widens slightly in the direction of the heat exchange area, so that the diameter of the burner chamber increases in the direction of the contiguous heat exchange area. The flow rate of the flue gases is thus controlled. It has surprisingly been found that thus the sound production of the burners can be limited during use. The increase is preferably gradual and only needs to be small, for instance a few millimeters across the height of the burner chamber.

The invention further relates to a method for forming a heat exchanger, in particular according to the invention, and a heating apparatus provided with such a heat exchanger.

The invention further relates to a member for use in a heat exchanger according to the invention.

For a better understanding of the invention, embodiments of a member, a heat exchanger and heating apparatus and of a method for the manufacture thereof according to the invention will be described in more detail with reference to the drawing, in which:

Figs. IA and B show, in perspective bottom view and top view, respectively, a member according to the invention;

Fig. 1C shows, in cross-sectional side view similar to Fig. 3, an alternative embodiment of a member according to the invention;

Fig. 2 shows, in front view, a member according to Fig. 1;

Fig. 3 shows, in cross-sectional side view according to line A — A in Fig. 2, a member according to the invention;

Fig. 4 shows, in top plan view, a member according to Figs. 1 — 3; Fig. 5 shows, in exploded perspective top view, a heat exchanger according to the invention, with three members, without closing plates;

Fig. 6 shows, in perspective bottom view, the heat exchanger according to claim 5, in assembled condition;

Fig. 7 shows, in cross-sectional side view similar to Fig. 3, a member according to the invention, in an alternative embodiment;

Fig. 8 shows, in top plan view, a heat exchanger according to the invention, built up from members according to Fig. 7, with detached closing plates;

Fig. 9 shows, in top plan view, a heat exchanger according to Fig. 8, with a first, second and third channel provided thereon; and Fig. 10 schematically shows, in front view, a heating apparatus according to the invention, provided with a heat exchanger with a series of members.

In this description, same or corresponding parts have same or corresponding reference numerals. The embodiments shown only serve to illustrate the invention and should not be taken as being limiting in any way. In the examples and description, always three members are included in a heat exchanger according to the invention. Of course, this may also be any other number, for instance one or two but also, for instance, six, eight or more. Figs. IA - C show a member 1 according to the invention in perspective bottom view and top view and an alternative embodiment thereof in side view, respectively, for the construction of a heat exchanger 30, for instance as shown in Figs. 5 and 6. This member 1 is preferably cast in light metal, for instance aluminum or an aluminum alloy or another suitable material. Light metal has the advantage of a good ratio of weight to heat capacity. The member 1 is shown in more detail in Figs. 2 - 4 in front view, side view and top view. The member 1 comprises a top surface 31 with an outlet 2, a burner position 4 with a burner 5 therein, an inlet 6 and a flue gas exhaust 7 therein next to one another. Below the burner position 4, a burner chamber 2 extends which connects to a heat exchange area 32 on the side remote from the top surface 31. The burner chamber 2 tapers slightly in the direction of the heat exchange area 32. Fig. 1C shows an alternative, particularly advantageous embodiment in which the burner chamber 2 widens slightly in the direction of the heat exchange area 32, which means that the cross-sectional surface of the burner chamber

2 increases slightly, substantially at right angles to the feed-through direction of the flue gases. It has been found that, when the occasion arises, a reduction of the sound level can thus be achieved during use of the heat exchanger. A burner cover 33 of the burner 5 extends into the burner chamber 2, at least faces it, so that, during use, flue gases heated by the burner can flow to the heat exchange area 32 in the direction of the arrows H.

Each of the embodiments shown in Figs. IA — C can be manufactured and used in the manner described. Between the inlet 6 and the outlet 3, a water-carrying channel 10 is provided, which extends on two sides of the burner chamber 2 and the heat exchange area 32 (in Fig. 2 on the left and right side, further to be referred to as front and back side) and runs below the heat exchange area 32. As a result, the channel has a slightly U-shaped side view and is bounded by the walls 13, 35 and 34. As Fig. 1 clearly shows, the water-carrying channel 10 is closed off by a wall 13 on the two sides of the member 1 (in Fig. 3 on the left and right side, further to be referred to as sides), while the burner chamber 2 and the heat exchange area 32 are open on the two sides.

Between the water-carrying channel 10 and the burner chamber 2 and the heat exchange area 32, on the front and back side, a partition wall 35 is provided. From a first part 35A of the two walls 35 which extends along the heat exchange area 32, heat-transferring surface-increasing elements 9, in the form of pins and/or ribs, preferably cast integrally therewith, extend in the heat exchange area 32. These heat-transferring surface -increasing elements 9 are placed and designed such that, between them, one or more meandering flow paths for flue gases are provided. Thus, during use, an intensive contact is obtained between above-mentioned elements and the walls 35 on the one hand and the flue gases on the other hand. On the side of the burner chamber 2 remote from the heat exchange area 32, a passage 11 is provided where the heat exchange area 32 connects to a flue gas feed-through 36. This flue gas feed-through 36 has a first part 12 extending below the heat exchange area 32 and the water-carrying channel 10 and an upward second part 12A extending in the direction of the top surface 31 between the wall 34 and the wall 8. In the top surface 31, the flue gas exhaust 7 is provided. In the flue gas feed-through 36, heat- transferring surface-increasing elements 9 extend from a part of the wall 35B extending along the water-carrying channel 10, for transferring residual heat in the flue gases to water in the water-carrying channel 10. In Fig. 2, the preferred flow direction of the water through the water-carrying channel 10 is shown by arrows W, which show that inflowing water, which will be relatively cool, flows along the flue gas passage, while water already heated up in the water-carrying channel 10 flows on the opposite side, so that always optimal use is made of heat in the flue gases for further heating the water.

As clearly appears from Figs. 2 and 3, the element or member 1 can have a rectangular front view and a flat top side. In the embodiment shown, the inlet 3, the burner position 4, the inlet 6 and the flue gas exhaust 7 are level. This can have constructive advantages for each member 1 but particularly also for coupling the outlets 3, the burner positions 4 or at least the burners 5, the inlets 6 and the flue gas exhausts 7, respectively. To this end, a first channel 40, a second channel 41, a third channel 42 and a fourth channel 43, respectively, can simply be provided above the juxtaposed top surfaces 31 of the different members 1, as schematically shown in Figs. 5 and 6. In this embodiment, the channels 40, 41, 42 and 43 all have a straight design and are provided in an extrusion profile 44 having four passages between a top and bottom wall 45, 46, separated from one another by cross walls 47 and two side walls 48.

By way of illustration, in Figs. 5 and 6, a heat exchanger 30 is shown which is provided with three members 1. These are placed next to one another, with interposition of suitable gaskets (not shown), thereby forming a row with a continuous burner chamber 2 and heat exchange areas 32. The end walls 15, 16 (Fig. 8) are omitted in Figs. 5 and 6 for simplification. The extrusion profile 44 has been sawn down to a length Li which is slightly larger than combined length L2 of the three members 1. In the bottom wall 46, in each channel 40 — 43, openings 49 — 52 are provided, corresponding to the outlets 3, the burner positions 4, the inlets 6 and the flue gas exhausts 7. A gasket with a similar hole pattern (not shown) may be provided between the extrusion profile 44 and the top surfaces 31, with overlapping holes, so that a gastight and liquid-tight sealing is obtained. The extrusion profile can be fixed in any suitable manner, for instance by screws, clamps, glues, form-locking, force-locking or the like. Also, for instance, separate brackets or the like may be used to this end.

In the upper wall 45, for each channel 40 — 43, a second opening 53 — 56 is provided, for connecting of, respectively (see Fig. 10):

- a first connection 70 for a supply of a space heating circuit 71 and/or a tap water supply 72 so that water can be led from the water-carrying channels 10 via the outlets 3 and the first channel 40 to above-mentioned connection 70; - a supply 73 for gas or a gas/air mixture to the second channel 41, so that, for instance via a mixing fan 74, gas or a gas/air mixture can be led to the different burners 5 via the second channel 41;

- a second connection 75, for instance a water supply 76 and/or a return pipe 77 of a space heating circuit 71 and/or a tap water heating circuit 72 so that, therefrom, water can be introduced into the different water-carrying channels 10 via the third channel 42 and the inlets 6; and

- a chimney 78 for exhausting flue gases supplied from the flue gas exhausts 7 via the fourth channel 43.

The two ends 57, 58 of the channels 40 — 43 can be closed off by closing plates 59, 60 (Fig. 10).

On the bottom side, below each channel part 12, a condensation outlet 61 is provided. A second extrusion profile 62 with again a length adjusted to the combined length of the members 1 extends below the members and is provided with a series of openings 63 (three in the example shown) which can connect to the condensation outlets 61 so that condensation can simply be collected and discharged.

It will be clear that a different number of members 1 can also be arranged next to one another, while the length of the profiles 45, 62 can simply be adjusted thereto and they can be provided with the desired numbers of holes 49 - 52 and 63, respectively.

Figs. 7 — 9 show an alternative embodiment of a member 1 according to the invention, for which substantially only the differences with the embodiment according to Figs. 1 — 6 will be described. For the reference numerals not discussed here, reference is made to the above description.

In the embodiment according to Figs. 7 — 9, the top surface 31 is substantially flat but only the outlet 3, the burner position 4 with the burner 5 and the inlet 6 are provided therein. Here, the flue gas exhaust 7 is provided on the front side (in Fig. 7 on the right side), in a plane approximately at right angles to the top surface 31. Around the inlet 6, outlet 3 and the burner position 4, always an upstanding edge 3A, 4A, 6A is provided which can serve as sealing for a first, second and third channel 40, 41 and 42.

In this embodiment, the profile 44 comprises only the first, second and third channel 40, 41 and 42. The flue gas exhausts can be connected to a chimney 78 in a different manner, for instance by individual pipes or by a second profile extending along the members in a similar manner. Incidentally, the fourth channel 43 may of course also be included in the extrusion profile 45, for instance by designing that profile 45 so as to be angular.

Fig. 8 shows a heat exchanger 30 built up from three members 1, with two closing plates 15, 16. Here, the or each igniter 17 is clearly visible. The closing plates are, for instance, screwed against the members 1, so that they can be removed for, for instance, inspection and cleaning. Also, a sight glass may be provided in one of the closing plates, preferably near the igniter 17. As Fig. 9 shows, the profile 44 has three channels 40, 41 and 42, separated by walls 47, 48 and enclosed between top and bottom wall 45, 46. Openings 49 — 51 are again provided for connection of a first and second connection 70, 75 and the gas or gas/air connection 73. As appears from the top view, the openings 49 - 51 (and 52 in Figs. 1 - 6) are preferably not located right opposite the underlying openings (inlet 6, outlet 3, burner position 4 or flue gas exhaust 7), in order to obtain a desired flow and a good distribution of water, gas/air and flue gases. In the embodiments shown, the profiles 44 and optionally 62 therefore have a longer design. In the embodiment shown in Figs. 7 — 9, no condensation drain is provided but it may of course be used, just as it may be omitted in the embodiment according to Figs. 1 — 6.

Fig. 10 shows a schematic representation of a heating apparatus 100 with a heat exchanger 30 according to the invention, with five members. The different parts are designated by the reference numerals mentioned above. The heat exchanger 30 is included in a housing 80, together with a control 81. A condensation drain 82 is shown schematically, connected to profile 62. The tap water supply 72 is designed with a heat exchanger but may of course be provided in any desired manner or be omitted. The space heating 71 is shown as central heating but may also be designed in a different manner or be omitted. Modifications thereof are readily apparent to a skilled person.

By way of illustration, some weights and measures as well as materials will be given, which examples should not be taken as being limiting in any way.

A segment or member 1 according to the invention may have a weight of 2 to 2.5 kg and be manufactured from aluminum alloy conventional in heating technology. A member may have outer dimensions, measured over the largest height, depth and width of, for instance, 200 by 230 by 80 mm, while, per member 1, for instance a capacity of about 7 kW can be reached. So, with four members, this means a width of 320 mm and a capacity of 28 kW. By adjustment of the number of members, that capacity can be increased or decreased as desired. Of course, members with different capacities may also be used. Also, for instance, two different members may be combined, which, for instance, differ from each other only in capacity, in different numbers, so that, with only two different members, a still greater variety of powers can be achieved. In each member, a burner 5 may be provided, with a circular shape or a cylindrical shape. Such a burner 5 may have a relatively small burner cover 33, for instance between 20 and 2000 mm², more in particular between 100 and 1000 mm². Thus, the burner may have a diameter of about 25 to 30 mm and a height of 10 to 15 mm. Of course, these dimensions may be adjusted as desired.

The invention is by no means limited to the embodiments shown and described in the description and drawings. Many variations thereof are possible within the framework of the invention set forth in the claims.

Thus, the first, second, third and fourth channel may, for instance, be accommodated in separate profiles or, for instance, in pairs. These may also be cast, drawn or be manufactured in a different manner. They are preferably straight but may also include an angle. The top surface may have a stepped or bent design, provided that the channels of the or each profile are adjusted thereto. The different openings may be provided in other positions. Other materials may be used for the members and the channels. Preferably, however, aluminum or an alloy thereof is used. The water- carrying channels are shown with a closing wall 13 on two sides. However, it will be clear that these may also be omitted on one or two sides, provided that the gaskets included between the members and the closing plates are adjusted thereto. Such modifications will be readily apparent to a skilled person. In the embodiment shown, each member 1 has only one water- carrying channel. Of course, this may also be two or more, for instance for separate water circuits. Also, members may be designed without a burner. The flue gas exhaust may extend in a direction different from the direction shown.

These and similar variations are understood to be within the framework of the invention set forth in the claims.

Claims

1. A heat exchanger (30), comprising a series of members (1), which members (1) are intercoupled, wherein: the members (1) each comprise a burner chamber (2) with a burner position (4), a heat exchange area (32), a flue gas feed-through (36), a flue gas exhaust (7) and a water-carrying channel (10) with an inlet (6) and an outlet (3); the members (1) are each arranged for comprising a burner (5) which at least partly extends in the respective burner chamber (2); the burner chambers (2) of the juxtaposed members are preferably in open connection with one another; and a first (4), second (41) and third channel (42) are provided, which interconnect the outlets (3), the burner positions (4) and the inlets (6) of the different members (1).

2. A heat exchanger according to claim 1, wherein closing plates (15, 16) are provided on two opposite ends (57, 58), for sealing a first and a last member (1) in said series, wherein, in at least one of the closing plates (15, 16), an igniter element (17) is provided.

3. A heat exchanger according to claim 1 or 2, wherein each of the members (1) has a top surface (31) in which at least two of the inlet (6), the outlet (3), the burner position (4) and the flue gas exhaust (7) are provided.

4. A heat exchanger according to claim 3, wherein at least three of said inlet (6), outlet (3), flue gas exhaust (7) and burner position (4) of each of the members (1) are located in said top surface (31), preferably all four of them, while the top surfaces 31 preferably form a surface facing upwards during use which extends over the combined members (1).

5. A heat exchanger according to any one of the preceding claims, wherein the heat exchange area (32) of each of the members (1) is provided with heat-transferring surface-increasing elements (9) such as cams and/or ribs, at least between the burner chamber (2) and the flue gas exhaust (7).

6. A heat exchanger according to any one of the preceding claims, wherein, in top plan view, each member (1) has a substantially rectangular view with next to one another at least two of the inlet (6), the burner position (4), the outlet (3) and the flue gas exhaust (7).

7. A heat exchanger according to claim 6, wherein, of each member (1), the inlet (6), burner position (4), outlet (3) and flue gas exhaust (7) extend next to one another.

8. A heat exchanger according to any one of the preceding claims, wherein the first (40), second (41) and third channel (42) are provided in one profile (44), in particular are substantially formed in an extrusion profile.

9. A heat exchanger according to any one of the preceding claims, wherein a fourth channel (43) extends along the flue gas exhausts (7).

10. A heat exchanger according to claim 8 and 9, wherein the fourth channel (43) is included in said profile (44).

11. A heat exchanger according to any one of the preceding claims, wherein a first part of the water-carrying channel (10) extends at least partly between the heat exchange area (32) and the flue gas exhaust (7).

12. A heat exchanger according to claim 11, wherein, in the flue gas exhaust (7), heat-transferring surface -increasing elements (9) such as cams and/or ribs are provided on a side proximal to the water-carrying channel (10).

13. A heat exchanger according to any one of the preceding claims, wherein the water-carrying channel (10) extends along at least two sides of the burner chamber (2) and at least two sides of the heat exchange area (32).

14. A heat exchanger according to any one of the preceding claims, wherein the burner chamber (2) increases in diameter in the direction of the heat exchange area (32).

15. A heat exchanger according to any one of the preceding claims, wherein, in the or each burner position (4) of each member (1), a burner (5) is provided, preferably a burner (5) with a total burner surface of between 20 and 2000 mm², more in particular between 100 and 1000 mm².

16. A heat exchanger according to any one of the preceding claims, wherein each member (1) is provided with a burner (5) with a substantially round cross section.

17. A heat exchanger (30), comprising, in a cast element (1), at least: a burner chamber (2) with a burner position (4), a heat exchange area (32), a flue gas feed-through (36), a flue gas exhaust (7) and a water- carrying channel (10) with an inlet (6) and an outlet (3), and a burner (5) extending at least partly in or near the respective burner chamber (2); and the burner chamber (2) is open on two opposite sides, wherein said cast element (1) is covered by a closing plate (15, 16) on said two opposite sides, wherein, in one of the closing plates (15, 26) at least one igniter (17) for the burner (5) is provided, wherein the cast element (1) is designed as one of the members (1) of a heat exchanger (30) according to any one of the preceding claims.

18. A method for forming a heat exchanger (30), in particular according to any one of the preceding claims, comprising the steps of: determining the required capacity of a heat exchanger (30); forming members (1), each with a capacity which is lower than the said required capacity; - coupling a series of members (1) for obtaining the said required capacity; providing a first (40), second (41), third (42) and preferably fourth channel (43) for intercoupling of inlets (6), burner positions (4), outlets (3) and flue gas exhausts (7) of the said series of members (1), respectively.

19. A heating apparatus (100), provided with a heat exchanger (30) according to any one of claims 1 — 17 or manufactured according to claim 18.

20. A member (1) for a heat exchanger (30) according to any one of claims 1 - 17 or a method according to claim 18.