US20120055421A1

US20120055421A1 - Sectional Boiler

Info

Publication number: US20120055421A1
Application number: US13/318,942
Authority: US
Inventors: Rainer Rausch
Original assignee: Individual
Current assignee: Robert Bosch GmbH
Priority date: 2009-06-10
Filing date: 2010-05-31
Publication date: 2012-03-08
Also published as: DE102009024442A1; WO2010142552A2; WO2010142552A3; EP2440855A2; EP2440855B1

Abstract

A sectional boiler is described as made of cast iron or aluminum, in particular a condensing boiler, having essential annular sections, a front section, at least one rear section and at least one center section being provided, which form a combustion chamber having an essentially surrounding heat exchanger made of a sectional block, whose annular water chambers are connected to one another and which has gap-like heating gas flues, which extend between two adjacent sections with a mutually adapted geometry approximately radially and empty into an exhaust gas collection chamber, and having a return port and a feed port. The present system is based on the objective of optimizing a sectional boiler made of cast iron or aluminum as a condensing boiler particularly with respect to compactness and robustness. The present system provides that the return port and the feed port are located on opposite sides of the sectional block, the flow passes through the water chambers of the sections in series starting from the return port, and the individual sections are respectively provided hydraulically with overflow openings in only one place on the periphery and are connected by these on at least one side with an adjacent section.

Description

FIELD OF THE INVENTION

The present invention relates to a sectional boiler, in particular a condensing boiler made of cast iron or aluminum materials.

BACKGROUND INFORMATION

Sectional boilers of this kind are made up of multiple boiler sections cast in one piece, which are arranged one behind the other and are normally connected to one another on the water side by hubs. A flow is thus created through the water channels and water pockets formed by the boiler sections between the return port and the feed port. Normally, generic sectional boilers have a lower return port and a feed port situated on top, which may be in the respective hub. The heating gases flow from the combustion chamber via downstream heating gas flues to an exhaust gas connection and on their way give off heat to the boiler water.
In all existing boilers of this kind, the sections are arranged in series one behind the other. There is an annular front section, on which a combustion chamber door or a burner plate may be fastened, one or multiple similarly designed center sections depending on the performance capacity, as well as one rear section. The combustion chamber extends through the front and center sections to the rear section, which forms the bottom of the combustion chamber with its cover-shaped design. In these specific embodiments, all boiler sections have similar outer dimensions because they form parts of the combustion chamber, heating gas flues and water chamber over the entire cross section of the boiler. Furthermore, boilers for low performance ranges are also known, which are made up of only two or even merely one boiler section.
With respect to the exhaust gas guidance and the efficiency of the heaters, one distinguishes between conventional heating technology and condensing heating technology. For reasons of saving energy, condensing heaters are increasingly used. The construction of their heat exchanger allows for the possibility of cooling the humid exhaust gases, which are produced when burning fuel and air in operation, to below the exhaust gas dew point. The humidity of the exhaust gases condenses out in the process, and, in addition to the sensible heat, the condensation heat is transmitted to the heating water.
In a use as a condensing boiler, particular value must be set on the selection of the material, for based on the composition of the utilized fuel and the combustion control, the exhaust gases are contaminated with pollutants, and the produced condensed water contains various acids in low concentration. The components touched by the condensed water such as heating surfaces, exhaust gas collector and exhaust gas line must therefore be resistant to the acids, which is why it is customary to manufacture these components from stainless steel, aluminum or plastic. Welded stainless steel heat exchangers are generally used especially in oil condensing heating technology, as also discussed for example in DE 10 2004 023 711 B3 as a spiral pipe winding. They offer the advantage of bearing the acid contamination without corrosion. Disadvantages are the high costs associated with the material as well as the less favorable scaling conditions especially in welded constructions of sheet metal, and the greater sizes, which are difficult to assemble in tight spatial conditions.
The heat exchangers of conventional heaters are often made of cast iron. They are characterized by high robustness and a long lifespan. Their construction from mostly identical cast segments allows for a cost-effective manufacture and easy scalability with respect to varying performance capacities and offers good assembly options even under tight set-up conditions. The material withstands very well the brief exhaust gas condensation phases at the start of operation and when the heat exchanger is cold. In today's form and design, cast iron is not suitable for condensing heating operation, however, where condensed water is produced for a longer period.
Furthermore, a condensing boiler having an integrated compact heat exchanger made of a corrosion-resistant material, which is hydraulically connected downstream, is discussed in DE 296 21 817 U1. As a separate component, this compact heat exchanger is enclosed by two shell-shaped boiler sections and is connected separately on the water side. All boilers having a heat exchanger connected downstream have the disadvantages of increasing the assembly costs because of the required pipe pieces and of raising the resistance on the water side. The arrangement as a separate exterior component also results in cooling losses, which must be reduced by a suitable thermal barrier.
German patent document DE 44 25 302 C2 discusses positioning the feed port and return port in a common upper boiler hub. For this purpose, a mixing zone is formed in the upper region of a common water chamber such that the incoming cold return water is preheated by the rising hot feed water. This deliberately prevents condensation in the area of the heating surfaces.

SUMMARY OF THE INVENTION

The exemplary embodiments and/or exemplary methods of the present invention are based on the objective of optimizing a sectional boiler made of cast iron or aluminum as a condensing boiler particularly with respect to compactness and robustness.
According to the exemplary embodiments and/or exemplary methods of the present invention, this objective is attained by the features described herein. Advantageous developments may be derived from the further features described herein.
The sectional boiler is characterized by the fact that the return port and the feed port are attached on opposite sides of the sectional block and that, starting from the return port, the flow passes through the water chambers of all sections one after the other in series. The individual sections are respectively provided with water-side overflow openings only in one place at the periphery and are connected by these on at least one side with an adjacent section. The overflow openings are used as a hydraulic connection to the respective adjacent section.
In the connection area, at least one flow guide arrangement is respectively attached within the overflow openings in the water chamber. This is made up of a wall that essentially divides the water chamber crosswise and is oriented approximately vertically to the axis of the connection area, which wall closes the respective flow channel and directs the incoming flow from the axial direction into the circumferential direction and directs the outgoing flow from the circumferential direction into the axial direction into the adjacent section. This wall may be positioned approximately at an angle of 30 to 50 degrees in the respective flow channel and may also have a curvature.
The return port, the feed port and the overflow openings between two adjacent sections are situated in alignment on one axis, the overflow openings being present only in one place at the periphery of the sections, which may be in the upper area.
The heating gas flues are divided into a primary segment, formed by the front section and at least one center section, and a secondary segment, formed by at least two rear sections. Starting respectively from the combustion chamber, the heating gas flues in the primary segment run approximately radially outward and empty into an exhaust gas collection chamber on the outside of the sections. There the heating gases flow over into the secondary segment, at least one heating gas flue in the secondary segment running from the exhaust gas collection chamber approximately radially inward to an exhaust gas connection.
The exhaust gas connection is situated on the common central axis of the sections and the combustion chamber. For this reason, the at least two rear sections have at least one opening in the extension of the exhaust gas connection, which is closed on the heating gas side within the rear section near the combustion chamber by a sealing plug, which is removable if necessary, for example for checking and cleaning purposes.
In a specific embodiment, the at least two rear sections respectively have in the water chamber a separating wall, running on the axis of symmetry, situated offset by approximately 180 degrees with respect to the connection area, between the wall of the opening and the inner side of the outer bounding wall, which respectively divides the water chamber into two halves. In the water chamber, the at least two rear sections furthermore respectively have a wall running around on a large part of a partial circle and recessed in the area of the separating wall between the wall of the opening and the inner side of the outer bounding wall. In each rear section, starting from the upper return port in the outer rear section, return water is thereby directed downward by the flow guide arrangement first in a half of the section outside of the circumferential wall, it flows near the separating wall into the inner flow channel of a smaller diameter within the circumferential wall, passes around the exhaust gas connection, then flows on the other side of the separating wall upward again outside of the circumferential wall, and thus, following the conclusion of the cycle at the sectional level, passes over into the adjacent subsequent section in the direction of flow in the connection area on the backside of the flow guide arrangement.
In another alternative and/or complementary specific embodiment, the individual sections respectively have on the heating water side an circumferential separating wall and are divided into at least one inner flow channel near the combustion chamber and at least one outer flow channel of a larger diameter. The inner flow channel near the combustion chamber has a smaller cross section than the outer flow channel far from the combustion chamber. In each section, the flow first passes through the outer and afterwards through the inner flow channel.
In the above alternative and/or complementary specific embodiment, the flow guide arrangement is essentially made of a wall standing vertically on the separating wall running in the circumferential direction, which closes the respective flow channel. Here too, this crosswise barrier may be disposed at an angle within a flow channel and may have a curvature. In this case, an overflow opening is situated in the front section in the area of the flow guide arrangement in the channels in the separating wall that runs in the circumferential direction between the channels.
Advantageously, the respective flow guide arrangement are situated in the inner and outer flow channel in such a way that they cross each other.
The exemplary embodiments and/or exemplary methods of the present invention provide for a sectional boiler with the best suitability for condensing heating operation, in which the positive material properties of cast iron or aluminum are specifically applied and utilized in order to ensure good heat transfer properties, compactness and robustness. Loads that trigger corrosion are intercepted. According to the exemplary embodiments and/or exemplary methods of the present invention, it is not only easy to apply and check a corrosion protection coating, but the latter is also protected in the gaps against possible mechanical stresses.
The division of the water and heating gas side into a primary and a secondary segment achieves an intensive heat exchange that is optimally adapted to the temperatures prevailing in the respective areas. In the secondary segment, the heating gases are even cooled on the outside of the outer rear section, that is, in the gap to the cover of the exhaust gas collector. This additionally increases the heat transfer surface. The overall system results in a very high efficiency, without increasing the complexity of the components and without producing limitations in the ability to clean.
In addition to the simple manufacture, the sectional construction also offers the advantage of allowing for different lengths for different heating and heat exchanger performances in a variable manner by inserting additional center sections. Nevertheless, all the attachment parts may be situated on the front side as well as the water-side connections remain the same. Only the surrounding jacket around the exhaust gas collection chamber varies. Due to the low exhaust gas temperatures, the latter may even be manufactured from plastic.
The division into two flow channels, described as the second specific embodiment, that is, the cooler heating water on the outside and the hotter heating water on the inside, optimizes the temperature distribution in the heat exchanger and increases the effectiveness compared to known principles. Moreover, the flow guidance is effected exclusively by the design of the sections, because no additional components such as feed-in and/or withdrawal pipes for example are required. In the construction according to the exemplary embodiments and/or exemplary methods of the present invention, the flow passes through the individual segments in series. The segments are connected only in one place and a second hub is not required. This increases the effective heat exchanger surface of the heater.
The drawings represent exemplary embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sectional boiler made of cast iron or aluminum in a perspective overall view with a section in the upper area.

FIG. 2 shows a sectional boiler made of cast iron or aluminum in a vertical longitudinal section through the system as a whole.

FIG. 3 shows a sectional boiler made of cast iron or aluminum in the front view of a rear section.

FIG. 4 shows the sectional boiler made of cast iron or aluminum in a rear section in a perspective view with a half-side section.

FIG. 5 shows the sectional boiler made of cast iron or aluminum in a front view of a center section in a second specific embodiment having two circumferential flow channels.

FIG. 6 shows a sectional boiler made of cast iron or aluminum in a perspective overall view of the overall system in a second specific embodiment having two circumferential flow channels according to FIG. 5 and having a section in the upper area.

FIG. 7 shows a sectional boiler made of cast iron or aluminum in a perspective view of a center section in a second specific embodiment having two circumferential flow channels according to FIGS. 5 and 6 and having a section through the outer flow channel in the connection area.

FIG. 8 shows a sectional boiler made of cast iron or aluminum in a perspective view of a center section in a second specific embodiment having two circumferential flow channels according to FIGS. 5, 6 and 7 and having a section through the inner flow channel in the connection area.

DETAILED DESCRIPTION

The sectional boiler is essentially made up of annular sections, namely, a front section 1, two rear section 2 and at least one center section 3. These form a combustion chamber 4 and their annular water chambers 5 are connected to one another.
The heat exchanger thus formed from a sectional block has gap-like heating gas flues 6, which extend approximately radially outward between two adjacent sections 1, 2, 3 having a mutually adapted geometry. Return port 7 and feed port 8 are located on opposite sides of the sectional block.
According to the exemplary embodiments and/or exemplary methods of the present invention, the heating gas flues are subdivided into a primary segment P and a secondary segment S. Front section 1 and at least one center section 3 thus belong on the water side and heating gas side to primary segment P, whereas the two rear sections 2 form secondary segment S.
Heating gas flues 6 run in primary segment P, respectively from combustion chamber 4, approximately radially outward, empty into an exhaust gas collection chamber 9 in the form of a hollow cylinder on the outside of sections 1, 2, 3, and there flow over into secondary segment S. In secondary segment S, heating gas flues 6 run from exhaust gas collection chamber 9 between the two rear sections 2 and on the outside of outer rear section 2 approximately radially inward to an exhaust gas connection 10 at the center of secondary segment S.
In the extension of exhaust gas connection 10, rear sections 2 have at least one opening 11, which is closed on the heating gas side by a sealing plug 12 within the rear section 2 near the combustion chamber. A condensed water drain 13 is furthermore provided.
Starting from return port 7, the flow passes through the water chambers of all sections 1, 2, 3 in series, and the individual sections 1, 2, 3 are respectively provided hydraulically with overflow openings 14 only in one place on the periphery, in the upper region in the figures. In these connection areas to adjacent sections 1, 2, 3, flat seals are provided as a sealing arrangement.
Within the respective overflow openings 14, respectively one flow guide arrangement 15 is attached, which is made up of a wall that divides water chamber 5 crosswise and is oriented approximately vertically with respect to the axis of the connection area. This closes the respective flow channel and directs the incoming flow from the axial direction into the circumferential direction and the outgoing flow from the circumferential direction into the axial direction respectively into adjacent section 1, 2, 3. Return port 7, feed port 8 and overflow openings 14 between two adjacent sections are disposed in alignment on one axis.
In the two rear sections 2, FIGS. 3 and 4 show respectively a separating wall 16 between the wall of the opening 11 and the inner side of the outer bounding wall that runs on the axis of symmetry in water chamber 5 and is offset by 180 degrees with respect to the connection area. In the illustrations, separating wall 16 points vertically downward and divides water chamber 5 into two halves. Furthermore, a symmetrically positioned wall 17, which runs around on a partial circle and is recessed in the area of separating wall, is situated in the two rear sections 2 respectively in water chamber 5. In each rear section 2, starting from upper return port 7, return water is thereby directed downward by flow guide arrangement 15 first in one half outside of circumferential wall 17, it flows near separating wall 16 into the inner flow channel of smaller diameter within circumferential wall 17, passes around opening 11, then flows on the other side of separating wall 16 upward again outside of circumferential wall 17, and in the connection area on the backside of flow guide arrangement 15 passes over into the adjacent section 2, 3.
According to FIGS. 5 through 8, in a second specific embodiment, water chambers 5 of individual sections 1, 2, 3 are respectively divided in the circumferential direction into two flow channels 5′, 5″ and have for this purpose a circumferential separating wall 18. This creates an inner flow channel 5′ near the combustion chamber and an outer flow channel 5″ of a greater diameter, the inner flow channel 5′near the combustion chamber having a smaller cross section than the outer flow channel 5″ far from the combustion chamber, and the flow passing in each section 1, 2, 3, first through the outer and then through the inner flow channel 5′, 5″. In the second specific embodiment therefore, feed port connection 8 is therefore also located on rear section 2, namely, above return port connection 7.
The transfer within the respective overflow openings 14 occurs as described above by flow guide arrangement 15, which are then however respectively attached in the individual flow channels 5′, 5″. In front section 1, in the area of flow guide arrangement 15, in the transition area between flow channels 5′, 5″, an overflow opening 19 is situated in the separating wall 18 between flow channels 5′, 5″ running in the circumferential direction such that there the direction of flow reverses when the channels are switched.

Claims

1-14. (canceled)

15. A sectional boiler made of cast iron or aluminum, which is a condensing boiler, comprising:

essential annular sections, including:

a front section;

at least one rear section; and

at least one center section;

wherein the sections form a combustion chamber having an essentially surrounding heat exchanger made of one sectional block, whose annular water chambers are connected to one another, and which has gap-like heating gas flues, which extend between two adjacent sections with a mutually adapted geometry approximately radially and empty into an exhaust gas collection chamber, and having a return port and a feed port, and

wherein the return port and the feed port are located on opposite sides of the sectional block, the flow passes through water chambers of the sections in series starting from the return port, and the individual sections are respectively provided hydraulically with overflow openings in only one place on the periphery and are connected to these on at least one side by an adjacent section.

16. The sectional boiler of claim 15, wherein the overflow openings are provided as hydraulic connections into the respectively adjacent section, and wherein at least one flow guide arrangement is mounted in the water chamber respectively in the connection area within the overflow openings.

17. The sectional boiler of claim 15, wherein a flow guide arrangement in the connection area of the water chamber is made up of a wall that essentially divides the water chamber crosswise and is oriented approximately vertically to the axis of the connection area, which wall closes the respective flow channel and directs the incoming flow from the axial direction into the circumferential direction and directs the outgoing flow from the circumferential direction into the axial direction into the adjacent section.

18. The sectional boiler of claim 15, wherein a flow guide arrangement in the form of a wall dividing the water chamber crosswise and oriented approximately vertically to the axis of the connection area is situated aslant approximately at an angle of 30 to 50 degrees in the respective flow channel.

19. The sectional boiler of claim 15, wherein the return port, the feed port and the overflow openings are situated between two adjacent sections in alignment on an axis and the overflow openings exist only in one place on the periphery of the sections.

20. The sectional boiler of claim 15, wherein the heating gas flues are subdivided into a primary segment, formed by the front section and at least one center section, and a secondary segment, formed by at least two rear sections, the heating gas flues in the primary segment running approximately radially outward respectively starting from the combustion chamber and emptying into an exhaust gas collection chamber on the outside of the sections, the heating gases there flowing over into the secondary segment, and in the secondary segment at least one heating gas flue running from the exhaust gas collection chamber approximately radially inward to an exhaust gas connection.

21. The sectional boiler of claim 15, wherein the exhaust gas connection is situated on the common center axis of the sections and the combustion chamber.

22. The sectional boiler of claim 15, wherein, in the extension of the exhaust gas connection, the at least two rear sections have at least one opening, and the latter is closed within the rear section near the combustion chamber by a sealing plug on the heating gas side.

23. The sectional boiler of claim 15, wherein the at least two rear sections respectively have in the water chamber a separating wall, running on the axis of symmetry, situated offset by approximately 180 degrees with respect to the connection area, between the wall of the opening and the inner side of the outer bounding wall, which respectively divides the water chamber into two halves.

24. The sectional boiler of claim 15, wherein the at least two rear sections respectively have in the water chamber a symmetrically disposed wall, which runs around on a large part of a partial circle and is recessed in the area of the separating wall between the wall of the opening and the inner side of the outer bounding wall such that return water, starting from the upper return port in each rear section is directed downward by the flow guide arrangement first in one half outside of the partially circumferential wall, flows near the separating wall into the inner flow channel of a smaller diameter within the circumferential wall, passes around the opening, then flows upward on the other side of the separating wall again outside of the circumferential wall and passes over into the adjacent section in the connecting area on the backside of the flow guide arrangement.

25. The sectional boiler of claim 15, wherein the individual sections respectively have on the heating water side at least one separating wall running around in the circumferential direction and are divided into at least one inner flow channel near the combustion chamber and at least one outer flow channel of a greater diameter, the inner flow channel near the combustion chamber having a smaller cross section than the outer flow channel far from the combustion chamber, and the flow in each section passing first through the outer and afterwards through the inner flow channel.

26. The sectional boiler of claim 15, wherein in the front section in the area of the flow guide arrangement in the flow channels an overflow opening is situated in the separating wall running in the circumferential direction between the flow channels.

27. The sectional boiler of claim 25, wherein the flow guide arrangement are made up essentially of a wall standing vertically on the separating wall running in the circumferential direction, which closes the respective flow channel.

28. The sectional boiler of claim 25, wherein the respective flow guide arrangement are situated in the inner flow channel and the outer flow channel so that they cross each other.