DE202009011326U1 - Heat exchanger for the flue gas duct of a furnace - Google Patents

Abstract

Heat exchanger for the flue gas duct of a heater, characterized by an elongated flue gas divider (2, 37, 51) for the flue gas flow (3, 38), which separates during operation parts of a flowing flue gas flow (38) from each other and parallel to each other and to the longitudinal axis (21 , 39) of the heat exchanger and thus leads to that of the flue gas duct with it, wherein the flue gas divider (2, 37, 51) is designed for the flow of a heat exchanging medium, via which heat of the channeled flue gases (7, 8, 9) is dissipated.

Description

The The present invention relates to a heat exchanger according to the preamble of protection claim 1.

Such Heat exchangers are placed in a chimney or duct arranged for the flue gases and should as possible large part of the residual heat of the flue gas of a heat source like a heater or a cheninen or other Make firing reusable. They are in various embodiments known.

So shows DE 201 03 124 a heat exchanger consisting of a double tube. The inner tube serves as a conduit for the flue gases, the outer tube forms the outside of the heat exchanger. The annular space between the inner tube and the outer tube is used for the heat exchange. In one embodiment, a water conduit is provided which is wrapped around the inner tube, adjacent thereto, so that the inner tube heated by the flue gases can deliver the heat to the water conduit where it is removed by the water. Here is advantageous that on the one hand the line for flue gases is still easy to clean, since the inner tube has a smooth inner surface, and on the other hand, the water-carrying coil (which would be expensive to clean) in the annulus is protected from contamination. The disadvantage, however, is that the heat transfer from the inner tube to the helix is problematic because it touches the inner tube substantially along a line.

In Another embodiment is therefore the annulus water flows through between the inner and outer tubes, so that the inner tube is surrounded by a water jacket. On Reason of the operation of the heat exchanger resulting results in irregular flow in the water jacket an irregular cooling of the inner, the flue gases leading tube, with the result that the Heat dissipation is not optimal.

The DE 10 2004 023 026 shows a combination of water jacket and coil, with the advantage that the heat exchanger can be extended as desired over its modular design, so that at least in long chimneys despite irregular or less efficient heat transfer, a larger proportion of residual heat can be made available. Here, however, increases the design effort, especially if the often prescribed thermal discharge assurance must be additionally provided.

In the CA 02499775 is disclosed, internally, to arrange the flue gases leading tube with this connected Wärmeleitbleche that pass through the inner tube, so that now heat from the inner core of the rising flue gases can be removed, which facilitates the rapid heat transfer between flue gases and the inner tube and could lead to shortening of the heat exchanger. However, the heat transfer from the inner tube to the coil wrapped around it remains unsolved.

The problem of the heat transfer from the wall of the flue gases conducting pipe to the cooling water cycle is improved solved by the in DE 40 10 151 shown arrangement, which consists of four coaxial tubes, which together form three annular spaces. The middle annulus serves as a conduit for the flue gases; the inner and the outer annulus ever as a conduit for the cooling medium, also here usually water. In addition, a helical baffle runs in the middle annulus, so that the flue gases no longer need to flow through it parallel to the longitudinal axis of the tubes, but along this baffle. On the one hand, this extends the path of the flue gases and, on the other hand, they flow between two walls receiving their heat, so that the disadvantages of the irregular heat transfer into the surrounding water jacket are reduced. The disadvantage of this design is that it is expensive and then necessarily either has an oversized overall diameter or scarce or too small flow cross-section for the flue gases. Finally, this arrangement is to be cleaned only with great effort.

Corresponding It is the object of the present invention, a heat exchanger for the flue gas to create the heat which dissipates flue gases efficiently, is easy to clean and so also as an insert in pre-existing flue gas ducts, such as B. fireplaces can be used.

These The object is achieved by the characterizing features of claim 1 or of claims 14 and 15 solved.

The fact that the heat exchanger has a flue gas divider, which is itself traversed by the heat-exchanging medium, the heat can be taken from the flue gases in their core area with maximum efficiency, since the temperature difference between the flue gases and the walls along which they swipe along, always remains as big as possible. In addition, the heat radiation of the flue gases is efficiently absorbed by the appropriate division of the flue gas flow. This applies over the entire cross section of the flue gas flow, and not only for its outer periphery. Flow barriers or vortex plates in Flue gas duct are no longer necessary.

There all walls parallel to the longitudinal axis of the heat exchanger run, there is no significant flow resistance for the flue gases. This is beneficial because of the natural Chimney draft at the now also in the core zone taking place strong cooling the flue gases considerably loses its effect. Further Simple cleaning is still possible as the individual formed by the partitions chambers of the cleaning tools can be easily passed through the length.

Surprised has been shown that in cooling even in the core zone (i.e., over the entire cross-section of the flue gas stream) the ejection of solids such as soot particles decreases considerably. this will on the now also in the core zone reduced flow velocity attributed at least for now larger particulate matter is no longer sufficient, to carry them out through a vertical flue. These particles fall back into the chimney, storing themselves at the lower end, which leads to an increased need for cleaning, which in turn proves the reduced solids ejection. For wood heating it further shows, the dyeings, z. B. the Braunfärbund of the smoke occur, which also reduces the amount of solids ejected and the resulting increased environmental friendliness.

at a method for operating the inventive heat exchanger this can be before the firing of the upstream firing z. B. with hot storage water to be flooded. The gases in the flue gas duct become so over its entire cross section on a minimum Temperature kept and only then cooled when the operating temperature of the system is reached. This already prevails in the phase of firing a train that comes close to that of normal operation, what The encouragement itself greatly facilitates and at the same time the education of pollutants in the combustion process during the Anfeuerprozess can diminish.

It it turns out that in addition to the heat recovery as such, the fine dust ejection is improved.

preferred Embodiments are in the dependent claims described.

The The invention will be explained in more detail below with reference to FIGS.

It shows:

1 a first embodiment of a heat exchanger according to the present invention

2 a second embodiment of a heat exchanger according to the present invention, and

3 A third embodiment of a heat exchanger according to the present invention.

1 shows a heat exchanger 1 with a flue gas divider 2 for one in the flue gas divider 2 entering flue gas stream 3 ,

Three partitions 4 . 5 . 6 separate the incoming flue gas stream 3 in three parts 7 . 8th . 9 from flue gas flow, which is behind the flue gas divider 2 again to a cooled flue gas stream 10 unite.

The partitions 4 . 5 . 6 are preferably thin but hollow; they can consist of V4A welded together at an acute angle welded together sheets. This can be done in the partitions 4 . 5 . 6 a heat exchanging medium, e.g. As water, flow through, which via the connecting piece 12 . 13 . 14 enter and over the spending port 15 . 16 . 17 can escape again. spigot 12 . 13 . 14 and dispensing nozzle 15 . 16 . 17 are shown only schematically in the figure and can easily be designed by the skilled person for the specific application and in the flue gas divider 2 to be built in. The flue gas divider 2 In other words, it is designed for the flow of the heat exchanging medium.

In the present case are the partitions 4 . 5 . 6 over a central tube 20 connected to each other, with the central tube 20 from the heat exchange medium is not flowed through. On the other hand, alternatively to the representation in 1 at the ends of the central tube 20 each a central connection or outlet connection are arranged, each with a branch line immediately thereafter, which leads into the ends of the partitions inside (or out of these), so that the heat-transporting medium from the central inlet into the partitions into distributed and then can be removed centrally. As a result, the heat exchanging medium continues to flow essentially through the partitions 4 . 5 . 6 ,

The flue gas divider 2 is elongated and has a longitudinal axis 21 ; he can be used in its length in any flue gas channel, z. As a chimney of a fireplace, a fireplace or a flue pipe of a heater or in any hot flue gases leading channel. In the case of heating, as in the other cases, the leadership of the supply and return lines for the the heat-transporting medium, preferably water, to be determined by a person skilled in the art; the guidance of these lines is dictated by the local conditions prevailing in a building. It is not mandatory, but advantageous that the flue gas divider 2 is dimensioned such that the outer longitudinal edges 25 . 26 . 27 abut the walls of the given flue gas channel.

As mentioned, during operation, a flowing flue gas flow 3 in parts 7 . 8th . 9 separated, which are parallel to each other and parallel to the longitudinal axis 20 be led; thus the parts flow 7 . 8th . 9 also parallel to the longitudinal axis of the flue gas duct. The hot flue gases heat via heat radiation and contact with the partitions 4 . 5 . 6 these on, which in turn give off the heat to the heat transporting medium (water).

By this arrangement is particularly in the middle of the flue gas duct flowing hot core of the flue gases effectively deprived of heat, without flow obstacles to the turbulence of the flue gases, which in turn complicate the chimney draft and the cleaning or impossible to provide.

Particularly advantageous are the partitions 4 . 5 . 6 made thin, so that the flow cross section for the flue gases is little reduced, with the result that additional blowers for the train in the flue gas duct are not necessary or have to have low power.

In a further embodiment, the central tube 20 connected to another coolant circuit due to excess temperature by a temperature sensor 72 ( 3 ) ak, and thus serves as emergency cooling in the sense of thermal discharge safety. Because the central tube 20 preferably does not flow through the heat exchanging medium (the wall surface of the central tube 20 is small compared to that of the partitions 4 to 6 ), it can nevertheless, despite the comparatively small efficiency, serve as an emergency cooling line.

2 shows a further embodiment of the inventive heat exchanger 30 , Shown are partitions 31 to 36 a flue gas divider 37 , the parts of the flue gas flow 38 channel.

Like the partitions 4 to 7 in 1 here too are the partitions 31 to 36 arranged in a star shape in cross section. Preferably, but not necessarily, these partitions are radially from a central longitudinal axis 21 ( 1 ) respectively. 39 of the flue gas divider 2 ( 1 ) respectively. 37 from. This forms in cross-section a symmetrical, multi-pointed star, through which the flue gas stream 38 is divided into the corresponding number parallel to each other flowing partial streams.

The optimal number of partitions, be it (in the sense of the star) a minimum of two ( 3 ), or three ( 1 ), or more, by the expert on the basis of the temperature of the incoming flue gases and the locally prevailing conditions such. B. determines the given masses of the flue gas channel.

The figure further shows that the partitions 31 to 36 with an inner tube 40 are connected, which in turn coaxial in an outer tube 41 is arranged. The inner tube 41 and the outer tube 42 form a double tube 43 which is an annulus 44 includes. This annulus 44 can also be provided for the flow of heat exchanging medium. Then each partial flow of flue gases is uniformly cooled on all sides.

Especially here, but also in the arrangement of 1 is advantageous if the partitions taper outwards, so that their thickness at the outer longitudinal edge 25 . 26 . 27 ( 1 ) is less than at the root. It is particularly advantageous if the thickness decreases continuously.

Z. B. enters the thickness of the partitions at the root in a flue gas duct with 200 mm diameter 22 mm, preferably only 16 mm. On the one hand, as mentioned above, the cross section the flue gas duct not too limited; then it will become quickly warm the water in the partitions, so that the flue gases are not below a temperature of z. B. 55 ° C fall, so the unwanted cold smoke and the formation essentially avoid condensation.

In 2 not shown is an embodiment in which the flue gas divider 37 not from a double tube 43 but is only enclosed by a simple tube. Such a simple tube serves to stabilize the partitions, so that z. B. central tube 18 can be omitted; Furthermore, this creates a heat exchanger, which can be used as an insert in any, z. B. masonry flue, as it can be found in older buildings, can be used. Alternatively, it is also possible for the heat exchanger tube thus formed to be used as a section to be exchanged in an existing flue gas pipeline. As related to above 1 mentioned, the heat exchanger can also be used without outer tube in the flue gas duct. It is advantageous then that a heat exchanger in a flue gas duct with irregular walls, z. As a coarse brick fireplace, can be easily used, which would no longer be possible with an outer tube.

3 shows a further embodiment of a heat exchanger 50 according to the present invention in a view from the outside. A flue gas divider 51 (which in cross section corresponds to a star with two points) is of a double-walled tube 52 consisting of an inner tube 53 and an outer tube 54 enclosed. Between the inner tube 53 and the outer tube 54 there is an annulus 55 , in which again a conduit 56 for a cooling medium such as water is arranged. The pipe 56 preferably runs around the inner tube 53 around, so that it lies on a helix extending over a length section, or the entire length of the heat exchanger 50 extends.

Next owns the pipe 56 a diameter that is the distance between the inner tube 53 and the outer tube 54 equivalent. So it's with both pipes 53 . 54 in contact. This will make the annulus 55 flowing medium is brought to a helical flow path through the annulus 55 leads through. In place of the pipeline 56 can also be provided a simple sheet or similar means; when using a line 56 However, there are the benefits described in more detail below.

In other words, in the annulus 55 Means are provided which determine the flow path of the heat exchanging medium, such that this the annulus 55 flows along a helical line. This results in a longer flow path and a longer residence time of the medium through the annulus 55 through, with the advantage of improved heat transfer between flue gas and heat-transporting medium.

Schematically in are further the connections for the annulus 55 shown: A connection 57 serves the inflow of cold water and a connection 58 the drain of the heated water. Likewise serves a connection 59 the inflow of cold water into the flue gas divider 51 and a connection 60 the outflow of heated water out of this. Depending on the design in the specific case, this can already be done in the annulus 55 heated water from the connection 58 directly into the connection 59 , and then in countercurrent through the flue gas divider 51 where it eventually heats up to an operating temperature of around 95 ° C and the connection 60 can be removed. Of course, other circuits of the water streams are possible, which in turn determined by the expert according to the local conditions.

The outer tube 54 is for illustrative purposes along the line 62 cut open, leaving the view of the inner tube 53 and a portion of the conduit 56 free is. It is clear that one is a cross bulkhead 63 trained flow obstacle for the annulus 55 flowing medium. Here, the transverse bulkhead consists of a plate which obstructs the flow path for the medium and which has a slot 64 possesses, through which the medium can flow. The edges of the slot 64 are preferably formed curved, as can be seen in the figure; which promotes the mixing and thus the uniform heating of the medium. Preferably, such a flow obstruction is provided in every fourth turn of the helical flow path. In addition, such a too fast flow through the heat-transporting medium can be avoided if the pump power is set too large.

A flue gas adapter 64 for the incoming flue gases 64 ' pierces the ground 65 of the heat exchanger 50 and releases them into the heat exchanger 50 to be introduced flue gases 64 ' slightly above the lower edge 66 of the inner tube 53 , Through the outer tube 54 , the ground 55 and the upper part of the flue gas adapter 64 becomes a groove 67 formed on the inner sidewall of the inner tube 53 trailing condensation absorbs, which by the also schematically indicated connection 68 can drain.

At the lower end of the flue gas divider 51 laterally from this projecting baffles 70 fulfill an analog function: Anything on the flue gas divider 51 Leaking condensation will pass through these baffles 70 against the wall of the inner tube 53 passed and then runs down, into the gutter 67 ,

Next in the figure is a temperature sensor 72 shown, which determines the temperature of the heated water. The temperature sensor 72 is connected to a not shown to relieve the figure control that at high temperature a cooling water connection 74 activated, leaving the line 56 flows through cooling water and the medium in the heat exchanger 50 cools. This results in a thermal discharge safety device in the event that the flow is disturbed by the heat exchanging medium. Advantageously, thus fulfilling the line 56 two functions: once that of a baffle for the flow path of the heat exchanging medium through the annulus 55 through, then the emergency cooling in the sense of thermal safety valve.

In a further embodiment, the flue gas divider is not provided, but the double tube 52 provided with all elements shown in the figure, and thus with a helical line 56 , Flow obstacles 63 a gutter 67 for condensation and a temperature sensor 72 for one through the line 56 formed equipped thermal discharge safety device.

The heat exchanger 1 for the flue gases of a heater owns a flue gas divider 2 , the incoming flue gases 3 in parallel partial streams 7 . 8th . 9 divides, with each of the partitions 4 . 5 . 6 flows through a heat-carrying medium, wel Ches absorbs the heat of the flue gases and feeds in the heating circuit. The heat exchanger can be used in the flue gas duct of a heater.

Of the inventive heat exchanger can also with a preheated medium are charged when z. B. in the flue gas duct the operating temperature has not been reached, such as this can be the case when lighting a heater. Is the flue gas channel too cold, the flue gases cool too hard, it prevails insufficient train, which in turn leads to a prolonged Kindling with the known disadvantages such. B. increased Pollutant production can lead. The under temperature (and also once reached lower operating temperature) in the flue gas duct can be detected via heat sensor or via the general temperature level in connection with the since the kindling be determined time elapsed. Depending on the local Ratios, the person skilled in the art can determine the suitable parameters. Once a lower operating temperature has been reached, through the heat transporting medium the flue gases, according to the normal operation, cooled.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 20103124 [0003]
• - DE 102004023026 [0005]
• - CA 02499775 [0006]
• - DE 4010151 [0007]

Claims (15)

Heat exchanger for the flue gas duct of a heater, characterized by an elongate flue gas divider ( 2 . 37 . 51 ) for the flue gas stream ( 3 . 38 ), which in operation parts of a flowing flue gas stream ( 38 ) separated from each other and parallel to each other and to the longitudinal axis ( 21 . 39 ) of the heat exchanger and thus leads to that of the flue gas duct with the flue gas divider ( 2 . 37 . 51 ) is formed for the flow of a heat exchanging medium, through which heat of the channeled flue gases ( 7 . 8th . 9 ) is discharged. Heat exchanger according to claim 1, wherein the flue gas divider ( 2 . 37 . 51 ) Partitions ( 4 . 5 . 6 ; 31 to 36 ) for the flue gas stream ( 3 ; 38 ), which are arranged in a star shape in cross section. Heat exchanger according to claim 2, wherein the flue gas divider ( 2 . 37 . 51 ) at least three radially from the central longitudinal axis ( 21 . 39 ) of the heat exchanger protruding partitions ( 4 . 5 . 6 ; 31 to 36 ), which form a symmetrical three-pointed star in cross section, such that in operation a flue gas stream ( 38 ) in at least three parallel to each other flowing substreams ( 7 . 8th . 9 ) is divided. Heat exchanger according to one of claims 2 or 3, wherein the thickness of the partitions ( 4 . 5 . 6 ) at its outer longitudinal edge ( 25 . 26 . 27 ) is smaller than in the region of its root, the thickness preferably decreasing continuously. Heat exchanger according to one of the claims 2 to 4, wherein the thickness of the partition walls at the root 22nd mm, preferably not exceeding 16 mm. Heat exchanger according to one of claims 2 to 5, wherein the heat exchanging medium in the heat exchanger substantially only by the partitions ( 4 . 5 . 6 ; 31 to 36 ) flows. Heat exchanger according to one of claims 2 to 6, wherein the flue gas divider ( 2 . 37 . 51 ) is connected to the outer longitudinal edges of its partitions along with a pipe which the flue gas divider ( 2 . 37 . 51 ) encloses. Heat exchanger according to claim 7, wherein the tube is double-walled, designed as a double tube, which has an annular space ( 55 ), which is provided for the flow of heat exchanging medium. Heat exchanger according to claim 8, wherein in the annulus ( 55 ) Means are provided which determine the flow path of the heat exchanging medium, such that this the annular space ( 55 ) flows along a helix, and wherein at least one flow obstruction is preferably provided in the flow path. A heat exchanger according to claim 9, wherein the at least one flow obstruction is a slotted transverse bulkhead (US Pat. 58 ) is formed, which is preferably provided after every fourth turn of the helix. Heat exchanger according to one of the preceding claims, wherein in areas traversed by the heat exchanging medium a line ( 56 ) is provided for a cooling medium. Heat exchanger according to claim 11 and 9, wherein the means for determining the flow path as a conduit, preferably as a pipeline ( 56 ) are formed for the cooling medium, wherein the line ( 56 ) the annulus ( 55 ) penetrated along a helix while the inner tube wall ( 53 ) as well as the outer pipe wall ( 54 ) touched. Heat exchanger according to one of claims 11 or 12, wherein a temperature sensor formed as part of a thermal discharge safety device ( 72 ) on the flue gas divider ( 2 . 37 . 51 ) and wherein a central tube ( 20 ) or the line ( 56 ) can be acted upon by the cooling medium via a controller in response to a temperature signal of the temperature sensor with cooling medium. Heating with a flue, which has a heat exchanger according to one of the preceding claims. Building with a heater according to claim 14.