EP0598691A1 - A heating boiler with flue-gas recirculation and a combustion chamber unit for such boilers - Google Patents
A heating boiler with flue-gas recirculation and a combustion chamber unit for such boilers Download PDFInfo
- Publication number
- EP0598691A1 EP0598691A1 EP93850219A EP93850219A EP0598691A1 EP 0598691 A1 EP0598691 A1 EP 0598691A1 EP 93850219 A EP93850219 A EP 93850219A EP 93850219 A EP93850219 A EP 93850219A EP 0598691 A1 EP0598691 A1 EP 0598691A1
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- EP
- European Patent Office
- Prior art keywords
- flue
- pipe
- wall
- gas
- combustion chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C3/00—Combustion apparatus characterised by the shape of the combustion chamber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
- F23C9/08—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for reducing temperature in combustion chamber, e.g. for protecting walls of combustion chamber
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- 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
- F24H1/24—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers
- F24H1/26—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body
- F24H1/263—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body with a dry-wall combustion chamber
Definitions
- the present invention relates to a heating boiler with flue-gas recirculation according to the preamble of Claim 1, and also to a combustion chamber unit for one such boiler.
- a heating boiler which includes a water storage facility or magazine that is surrounded by a cylindrical combustion chamber is described in our European Patent Specification EP 0166703.
- This boiler is a so-called low temperature boiler with which the thermal energy of the flue gases is used effectively by dividing the flue-gas channels, which are located between the water magazine and the combustion chamber, into four groups so that flue gases arriving from the combustion chamber on the burner side are led to the lower group of channels and from there to side channels by means of a flue-gas turning chamber on the opposite side of the burner side, and are then led from the side channels to the upper group of channels by means of a second flue-gas turning chamber on the burner side, this upper group of channels leading the flue gases to a flue-gas exhaust pipe.
- NO X nitrogen oxide content
- One known solution in this regard involves recirculating part of the flue gases to the combustion chamber to a location in the vicinity of the burner, so that the gases generated in the combustion chamber are dilute with the flue gases and therewith dampen the process of combustion and also contribute towards maintaining the fuel combustion temperature at a level which can be kept sufficiently low to counteract the formation of NO x .
- Heating boilers in which flue gases are recirculated to dilute added reactants are described in DE-A1-3601000, DE-A1-3628293, DE-C1-3738623 and EP-A-0288031, for instance.
- the dilution of added reactants by recycling the flue gases of such boilers is not sufficient to lower the nitrogen oxide content of the gases.
- DE-A-4 035 262 describes a boiler of this kind which has a through-penetrating gap for removing flue gases from the combustion chamber. These gases are passed towards the burner side, from where part of the flue gas is recycled back to the combustion chamber and part of the flue gas is taken out through four separate connecting conduits to a smoke stack. This results in a relatively complicated construction.
- the Heimax boiler Another such boiler, called the Heimax boiler, is described in DE-A-3905762 in which the volume of flue gases cooled and recycled can be adapted to the type of fuel concerned and also to other factors which influence the combustion process, by varying the size of the gap through which the cooled flue gases are recycled.
- This type of heating boiler fulfils all current requirements concerning low NO X emissions and thus represents an effective solution to this problem.
- one drawback with this type of heating boiler is that, similarto the boiler described in DE-A-4 035 262, it is of relatively complicated construction and is therewith more expensive than other commercially available boilers which are less attractive from the aspect of NO X emissions.
- the construction of the Heimax boiler is also made complicated by the requirement of additional channels for rearward outlet of the flue gases.
- the object of the present invention is to provide a heating boilerwhich will satisfy the aforesaid needs and demands, and also to provide a boiler combustion chamber unit by means of which a heating boiler comprising a water magazine that surrounds the combustion chamber can be modified in the manner indicated above.
- the invention thus relates to a heating boiler which operates with flue-gas recirculation, said boiler comprising a water magazine which is surrounded by an outer and an inner circular shell.
- the outer mantle normally has an oval shape, but may also be circular or even rectangular in shape.
- the boi ler has two outer walls and a cylindrical combustion chamber which is located inwardly of the inner shell and the outerwalls.
- the combustion chamber includes a plurality of surrounding flue-gas channels or passageways which are mutually divided by longitudinally extending flanges, fins or the like, for instance U-shaped profiles, arranged around the periphery of the circular inner shell of the water magazine.
- the combustion chamber is defined by a cylindrical pipe, a wall at one end of the pipe, said wall being provided with a burner-accommodating opening, and an imperforate second wall on the other end of the pipe.
- the cylindrical pipe is provided with a saddle-shaped aperture which is located in the vicinity of the other, distal wall and which extends at most around half the circumference of the pipe. This aperture communicates solely with a first group of flue-gas channels, including those flue gas channels that are located essentially in the vicinity of said half circumference and which in turn communicate solely with a flue-gas turning chamber provided on the burner side.
- the flue-gas turning chamber is defined by the outer wall on this side and by the wall that contains the burner opening.
- the flue-gas turning chamber is connected to the combustion chamber through a gap located in the vicinity of the burner opening, and also to a second group of flue-gas channels which include the remainder of said flue gas channels and which are connected to a flue-gas pipe which extends through the outer wall opposite to the burner side.
- the flue-gas pipe communicates with the surroundings.
- the size of the flue-gas recirculating gap can be adjusted and that the recirculated, cooled flue gases will be returned to the combustion chamber essentially in a circular pattern around the burner flame.
- the inventive heating boiler thus presents two so-called flue-gas paths, a lower path and an upper path, wherein the upper path is preferably connected to the combustion chamber through the outlet provided in the combustion chamber pipe.
- the flue gases will thus exit from the combustion chamber outlet and move upwards to the upper flue-gas path, which is comprised of a plurality of flue-gas channels in the upper half of the boiler.
- the combustion chamber can conveniently be constructed as a readily removable unit which lies sealingly against those flanges that form part of the flue-gas channels.
- the combustion-chamber pipe will then form one of the defining surfaces of the flue-gas channels.
- the inventive combustion chamber unit is intended for a heating boiler which operates with flue-gas recirculation and which comprises a water magazine having a circular inner shell, as defined in the preamble of Claim 1.
- the unit includes a cylindrical pipe having a first wall which is provided with a burner-accommodating opening. The other end of the pipe is fitted with an imperforate, second, distal wall.
- the pipe is provided with a saddle-shaped aperture or opening adjacent the distal wall, this aperture extending around half the periphery of the pipe.
- Also provided on the distal wall is an outwardly projecting edge which seals sealingly against the outer wall, such as to delimit the lower flue-gas path from the upper path.
- This edge may have different shapes and the shape of said edge will depend on whether or not the flue-gas pipe is seated in the lower part of the outer wall. For instance, the edge may be straight when the pipe is located in the lower half of the outer shell. If not, the edge must have a curved or some other non-straight shape, so as to provide room for the flue-gas pipe beneath the edge.
- the combustion chamber unit is conveniently insulated internally on the inner surface opposite to said aperture, this insulation covering said inner surface, either completely or partially, up to the level of the longitudinally extending fins or wings. Two diametrically opposed and radially arranged wings or fins, in the form of welded sheet- metal strips for instance, extend in the combustion chamber pipe throughout the whole of its length.
- the wings are dimensioned so as to sealingly abut the inner shell of the circular water magazine, and function to further delimit the two flue-gas paths one from the other. These rings also function to stabilize mounting of the combustion pipe inwardly of the flue-gas channel flanges.
- Figure 1 is a longitudinal, sectional view of an inventive heating boiler
- Figures 2 and 3 are sectional views of the inventive heating boiler taken on the lines A-A and B-B respectively in Figure 1
- Figures 4 and 5 are respective perspective views of a combustion chamber unit as seen from two different directions.
- FIG. 1 illustrates a heating boiler 10 which includes a water magazine 11 enclosed between an outer shell 12 and an inner shell 13.
- the outer surface of the outer shell 12 is insulated.
- Extending peripherally around the inner surface of the inner shell 13 are flanges 15 or the like which partially define longitudinally extending flue-gas channels.
- These flanges may have the form of U-shaped profiles and have a radial extension which is generally equal to the distance to a cylindrical combustion-chamber pipe 16 mounted inwardly of the inner shell 13, thereby forming a plurality of longitudinally extending flue-gas channels 17 outside the combustion-chamber pipe 16.
- the wall 18 is provided with an opening in which a burner 21 is mounted, said burner being shown fitted to the boiler.
- the other end of the pipe 16 has an imperforate wall 19, which is shown to be fitted with internal insulation.
- An aperture 22 through which flue gases exit from the combustion chamber20 is provided in the end of the pipe 16 opposite to the burner opening.
- the wall 18 at the burner end of the pipe 16 is configured to form a gap 23 between the wall 18 and an outer wall 25 of the boiler.
- the burner 21 When the boiler is in operation, the burner 21 is inserted into the opening in the wall 18 of the combustion chamber and the outer wall 25 of the boiler.
- the cooled flue gases reach a flue-gas turning chamber 14 located between the combustion chamber and the outer wall, and part of the thus cooled flue gases, or combustion gases, are drawn by suction through the gap 23 located around the burner 21 or the burner pipe 24, where they cool and dilute the combustion reactants and therewith enable a desired low combustion temperature to be achieved.
- the remainder of the flue gases flow back from the flue-gas turning chamber 14 towards the distal end of the boiler, through the lower group 17b offlue-gas channels and are therewith furthercooled from a temperature of about 300°C to a temperature beneath 200°C at the time of reaching the outer wall 27 of the boiler, as indicated in the Figure.
- the inner surface of the bottom half of the combustion chamber pipe 16 is insulated, as shown at 26, to prevent reheating of the cooled flue gases.
- the outer wall 27 which has mounted therein a flue-gas pipe 28 through which the gases are caused to exit to the surroundings, through a smokestack or the like.
- An outwardly projecting edge 29 seals against the outer wall 27 and the combustion-chamber wall 19 and is connected to wings 30 (shown in Fig. 2) disposed along the long side of the burner pipe 16 and therewith forces the flue gases flowing from the burner side to pass solely through the flue-gas pipe 28 in the outer wall 27.
- Figures 2 and 3 are sectional views of the boiler taken on respective lines A-A and B-B in Figure 1 and show the inner shell 13 of the water magazine.
- Connected to the inner shell 13 are longitudinally extending flanges 15. These flanges 15 define longitudinally extending flue-gas channels 17 together with the combustion-chamber pipe 16.
- the channels 17 are divided into two groups or paths by means of a seal located between the inner shell 13 of the water magazine and the combustion-chamber pipe 16.
- the seal has the form of a longitudinally extending wing 30 which is welded along the combustion-chamber pipe 16 and the width and length of which is such as to seal against the inner shell 13 of said magazine along the whole length of the pipe 16.
- Flue gases will thus flow inwardly, as seen in the plane of the drawing, in the upper group of flue-gas channels 17a, thus the group located above the wing 13, whereas the gases in the lower group of flue-gas channels 17b will flow outwards.
- the sealing, outwardly projecting edge 29 on the distal combustion-chamber wall 19 is configured to adapt to the flue-gas pipe 28, the position of which is also shown in the Figures.
- FIGS 4 and 5 illustrate a combustion chamber unit 31 constructed in accordance with a preferred embodiment of the invention, said unit being shown in perspective obliquely from above the burner side and the flue-gas pipe side respectively.
- the combustion chamber unit 31 is comprised of a cylindrical pipe 16 having a wall 18, which is provided with a burner accommodating opening 32, and an imperforate wall 19 at the opposite end of the pipe 16.
- This opposite end of the pipe 16 is provided with the aforesaid saddle-shaped aperture 22 through which the flue gases flow into the combustion chamber.
- the Figures illustrate the wings 30 extending along the sides of the pipe 16, these wings having the form of elongated narrow plates that are welded to the pipe, for instance.
- combustion chamber unit 31 Located at the distal wall 19 is an outwardly projecting edge 29 whose ends are connected to respective wings 30, said edge having the form of a bent plate in the illustrated embodiment.
- the entire combustion chamber unit 31 is intended to be fitted to a heating boiler that comprises a water magazine having a circular inner shell and flanges or profiles which define flue-gas channels inwardly of the shell, as described above.
- the unit 31 may be used conveniently to replace other combustion chamber arrangements fitted in such heating boilers.
- the aforedescribed arrangements operate in a manner which is highly satisfactory from an environmental point of view, since the NO X content can be kept very low ( ⁇ 120 mg/kWh).
- the arrangements involved are extremely simple mechanical constructions which can be produced simply and cheaply.
- the arrangements are also easy handle from a servicing aspect. When cleaning the unit, the outer wall 25 is removed and the combustion chamber unit 31 withdrawn from the boiler. When servicing or cleaning is completed, the unit 31 is simply inserted into the boiler and the boiler is then again operative.
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- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
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- General Engineering & Computer Science (AREA)
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- Thermal Sciences (AREA)
- Combustion Of Fluid Fuel (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
Abstract
Description
- The present invention relates to a heating boiler with flue-gas recirculation according to the preamble of Claim 1, and also to a combustion chamber unit for one such boiler.
- A heating boiler which includes a water storage facility or magazine that is surrounded by a cylindrical combustion chamber is described in our European Patent Specification EP 0166703. This boiler is a so-called low temperature boiler with which the thermal energy of the flue gases is used effectively by dividing the flue-gas channels, which are located between the water magazine and the combustion chamber, into four groups so that flue gases arriving from the combustion chamber on the burner side are led to the lower group of channels and from there to side channels by means of a flue-gas turning chamber on the opposite side of the burner side, and are then led from the side channels to the upper group of channels by means of a second flue-gas turning chamber on the burner side, this upper group of channels leading the flue gases to a flue-gas exhaust pipe.
- For environmental reasons, strict requirements are placed on the nitrogen oxide content (NOX) of the flue gases and, accordingly, strenuous efforts have been made in recent times to further reduce the NOX contents of gases generated in low temperature boilers of the kind defined in the introduction. One known solution in this regard involves recirculating part of the flue gases to the combustion chamber to a location in the vicinity of the burner, so that the gases generated in the combustion chamber are dilute with the flue gases and therewith dampen the process of combustion and also contribute towards maintaining the fuel combustion temperature at a level which can be kept sufficiently low to counteract the formation of NOx. Heating boilers in which flue gases are recirculated to dilute added reactants are described in DE-A1-3601000, DE-A1-3628293, DE-C1-3738623 and EP-A-0288031, for instance. When seen against the background of the ever increasing strict demands placed on the emission of harmful substances, the dilution of added reactants by recycling the flue gases of such boilers is not sufficient to lower the nitrogen oxide content of the gases.
- Consequently, it has been proposed to first cool the flue gases and then recirculate the gases to the combustion chamber. In this case, the recirculated gases have both a diluting and a cooling effect on the process of combustion, therewith further reducing the nitrogen oxide content of the gases in comparison with heating boilers in which the flue gases are only recycled and not cooled. DE-A-4 035 262 describes a boiler of this kind which has a through-penetrating gap for removing flue gases from the combustion chamber. These gases are passed towards the burner side, from where part of the flue gas is recycled back to the combustion chamber and part of the flue gas is taken out through four separate connecting conduits to a smoke stack. This results in a relatively complicated construction. Another such boiler, called the Heimax boiler, is described in DE-A-3905762 in which the volume of flue gases cooled and recycled can be adapted to the type of fuel concerned and also to other factors which influence the combustion process, by varying the size of the gap through which the cooled flue gases are recycled. This type of heating boiler fulfils all current requirements concerning low NOX emissions and thus represents an effective solution to this problem. However, one drawback with this type of heating boiler is that, similarto the boiler described in DE-A-4 035 262, it is of relatively complicated construction and is therewith more expensive than other commercially available boilers which are less attractive from the aspect of NOX emissions. The construction of the Heimax boiler is also made complicated by the requirement of additional channels for rearward outlet of the flue gases.
- Thus, there is a need for a heating boiler with which the flue gases have a sufficiently low NOX content but which can be found more attractive to those who would otherwise choose a less expensive but environmentally inferior heating boiler, for instance of the kind described above. There is also a need to be able to modify existing standard boilers, for instance boilers in which a water magazine surrounds a cylindrical combustion chamber and of which large numbers are to be found in many countries, so as to enable these boilers to be used while conforming to the stricter requirements concerning NOX emissions.
- The object of the present invention is to provide a heating boilerwhich will satisfy the aforesaid needs and demands, and also to provide a boiler combustion chamber unit by means of which a heating boiler comprising a water magazine that surrounds the combustion chamber can be modified in the manner indicated above.
- These objects are achieved with a heating boiler having the features set forth in Claims 1-5, and with a combustion chamber unit which can be fitted to such a boiler and which has the features set forth in Claims 6-10.
- The invention thus relates to a heating boiler which operates with flue-gas recirculation, said boiler comprising a water magazine which is surrounded by an outer and an inner circular shell. The outer mantle normally has an oval shape, but may also be circular or even rectangular in shape. The boi ler has two outer walls and a cylindrical combustion chamber which is located inwardly of the inner shell and the outerwalls. The combustion chamber includes a plurality of surrounding flue-gas channels or passageways which are mutually divided by longitudinally extending flanges, fins or the like, for instance U-shaped profiles, arranged around the periphery of the circular inner shell of the water magazine. The combustion chamber is defined by a cylindrical pipe, a wall at one end of the pipe, said wall being provided with a burner-accommodating opening, and an imperforate second wall on the other end of the pipe. The cylindrical pipe is provided with a saddle-shaped aperture which is located in the vicinity of the other, distal wall and which extends at most around half the circumference of the pipe. This aperture communicates solely with a first group of flue-gas channels, including those flue gas channels that are located essentially in the vicinity of said half circumference and which in turn communicate solely with a flue-gas turning chamber provided on the burner side. The flue-gas turning chamber is defined by the outer wall on this side and by the wall that contains the burner opening. The flue-gas turning chamber is connected to the combustion chamber through a gap located in the vicinity of the burner opening, and also to a second group of flue-gas channels which include the remainder of said flue gas channels and which are connected to a flue-gas pipe which extends through the outer wall opposite to the burner side. The flue-gas pipe communicates with the surroundings.
- It is preferred that the size of the flue-gas recirculating gap can be adjusted and that the recirculated, cooled flue gases will be returned to the combustion chamber essentially in a circular pattern around the burner flame.
- The inventive heating boiler thus presents two so-called flue-gas paths, a lower path and an upper path, wherein the upper path is preferably connected to the combustion chamber through the outlet provided in the combustion chamber pipe. The flue gases will thus exit from the combustion chamber outlet and move upwards to the upper flue-gas path, which is comprised of a plurality of flue-gas channels in the upper half of the boiler.
- Subsequent to being turned in the flue-gas turning chamber on the burner side, those flue gases that are not recirculated to the combustion chamber are forced to flow in the direction of the flue-gas path towards the flue-gas pipe, and then through the pipe and out to atmosphere. As the flue gases pass along the two flue-gas paths, the gases are cooled by the colder water in the circular water magazine that borders on the two flue-gas paths. So as to achieve further cooling of the flue gases, it is convenient to thermally insulate the flue-gas path outgoing from the combustion chamber, either completely or partially, preferably by insulating the lower, inner half of the combustion chamber pipe. It will be evident from the aforegoing that the aperture in the cylindrical combustion-chamber pipe will preferably face upwards, wherein the first group of flue-gas channels border essentially on the upper half of the cylindrical water magazine.
- The combustion chamber can conveniently be constructed as a readily removable unit which lies sealingly against those flanges that form part of the flue-gas channels. The combustion-chamber pipe will then form one of the defining surfaces of the flue-gas channels.
- The inventive combustion chamber unit is intended for a heating boiler which operates with flue-gas recirculation and which comprises a water magazine having a circular inner shell, as defined in the preamble of Claim 1. The unit includes a cylindrical pipe having a first wall which is provided with a burner-accommodating opening. The other end of the pipe is fitted with an imperforate, second, distal wall. The pipe is provided with a saddle-shaped aperture or opening adjacent the distal wall, this aperture extending around half the periphery of the pipe. Also provided on the distal wall is an outwardly projecting edge which seals sealingly against the outer wall, such as to delimit the lower flue-gas path from the upper path. This edge may have different shapes and the shape of said edge will depend on whether or not the flue-gas pipe is seated in the lower part of the outer wall. For instance, the edge may be straight when the pipe is located in the lower half of the outer shell. If not, the edge must have a curved or some other non-straight shape, so as to provide room for the flue-gas pipe beneath the edge. The combustion chamber unit is conveniently insulated internally on the inner surface opposite to said aperture, this insulation covering said inner surface, either completely or partially, up to the level of the longitudinally extending fins or wings. Two diametrically opposed and radially arranged wings or fins, in the form of welded sheet- metal strips for instance, extend in the combustion chamber pipe throughout the whole of its length. The wings are dimensioned so as to sealingly abut the inner shell of the circular water magazine, and function to further delimit the two flue-gas paths one from the other. These rings also function to stabilize mounting of the combustion pipe inwardly of the flue-gas channel flanges.
- The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 is a longitudinal, sectional view of an inventive heating boiler; Figures 2 and 3 are sectional views of the inventive heating boiler taken on the lines A-A and B-B respectively in Figure 1; and Figures 4 and 5 are respective perspective views of a combustion chamber unit as seen from two different directions.
- Figure 1 illustrates a
heating boiler 10 which includes awater magazine 11 enclosed between anouter shell 12 and aninner shell 13. Although not shown, the outer surface of theouter shell 12 is insulated. Extending peripherally around the inner surface of theinner shell 13 areflanges 15 or the like which partially define longitudinally extending flue-gas channels. These flanges may have the form of U-shaped profiles and have a radial extension which is generally equal to the distance to a cylindrical combustion-chamber pipe 16 mounted inwardly of theinner shell 13, thereby forming a plurality of longitudinally extending flue-gas channels 17 outside the combustion-chamber pipe 16. The boilerfurthercompris- es acombustion chamber 20, which is defined by the cylindrical combustion-chamber pipe 16 andcombustion chamber walls wall 18 is provided with an opening in which aburner 21 is mounted, said burner being shown fitted to the boiler. The other end of thepipe 16 has animperforate wall 19, which is shown to be fitted with internal insulation. Anaperture 22 through which flue gases exit from the combustion chamber20 is provided in the end of thepipe 16 opposite to the burner opening. Thewall 18 at the burner end of thepipe 16 is configured to form agap 23 between thewall 18 and anouter wall 25 of the boiler. - When the boiler is in operation, the
burner 21 is inserted into the opening in thewall 18 of the combustion chamber and theouter wall 25 of the boiler. The combustion gases from theburner 21, which reach a temperature of about 1000°C at the distal end of thechamber 20, exit through theoutlet aperture 22, as indicated by the flame symbols, and are therewith forced to flow in a reverse direction through the upper group offlue-gas channels 17, this upper group being referenced 17a, and are there cooled by the water in the upper part of thewater magazine 11, to achieve a temperature of about 300-500°C at the burner end. At the burner end, the cooled flue gases reach a flue-gas turning chamber 14 located between the combustion chamber and the outer wall, and part of the thus cooled flue gases, or combustion gases, are drawn by suction through thegap 23 located around theburner 21 or theburner pipe 24, where they cool and dilute the combustion reactants and therewith enable a desired low combustion temperature to be achieved. The remainder of the flue gases flow back from the flue-gas turning chamber 14 towards the distal end of the boiler, through thelower group 17b offlue-gas channels and are therewith furthercooled from a temperature of about 300°C to a temperature beneath 200°C at the time of reaching theouter wall 27 of the boiler, as indicated in the Figure. The inner surface of the bottom half of thecombustion chamber pipe 16 is insulated, as shown at 26, to prevent reheating of the cooled flue gases. Located at the distal end is theouter wall 27 which has mounted therein a flue-gas pipe 28 through which the gases are caused to exit to the surroundings, through a smokestack or the like. An outwardly projectingedge 29 seals against theouter wall 27 and the combustion-chamber wall 19 and is connected to wings 30 (shown in Fig. 2) disposed along the long side of theburner pipe 16 and therewith forces the flue gases flowing from the burner side to pass solely through the flue-gas pipe 28 in theouter wall 27. - Figures 2 and 3 are sectional views of the boiler taken on respective lines A-A and B-B in Figure 1 and show the
inner shell 13 of the water magazine. Connected to theinner shell 13 are longitudinally extendingflanges 15. Theseflanges 15 define longitudinally extending flue-gas channels 17 together with the combustion-chamber pipe 16. Thechannels 17 are divided into two groups or paths by means of a seal located between theinner shell 13 of the water magazine and the combustion-chamber pipe 16. In the illustrated case, the seal has the form of alongitudinally extending wing 30 which is welded along the combustion-chamber pipe 16 and the width and length of which is such as to seal against theinner shell 13 of said magazine along the whole length of thepipe 16. Flue gases will thus flow inwardly, as seen in the plane of the drawing, in the upper group of flue-gas channels 17a, thus the group located above thewing 13, whereas the gases in the lower group of flue-gas channels 17b will flow outwards. It will be seen that the sealing, outwardly projectingedge 29 on the distal combustion-chamber wall 19 is configured to adapt to the flue-gas pipe 28, the position of which is also shown in the Figures. - Figures 4 and 5 illustrate a
combustion chamber unit 31 constructed in accordance with a preferred embodiment of the invention, said unit being shown in perspective obliquely from above the burner side and the flue-gas pipe side respectively. Thecombustion chamber unit 31 is comprised of acylindrical pipe 16 having awall 18, which is provided with aburner accommodating opening 32, and animperforate wall 19 at the opposite end of thepipe 16. This opposite end of thepipe 16 is provided with the aforesaid saddle-shapedaperture 22 through which the flue gases flow into the combustion chamber. The Figures illustrate thewings 30 extending along the sides of thepipe 16, these wings having the form of elongated narrow plates that are welded to the pipe, for instance. Located at thedistal wall 19 is an outwardly projectingedge 29 whose ends are connected torespective wings 30, said edge having the form of a bent plate in the illustrated embodiment. The entirecombustion chamber unit 31 is intended to be fitted to a heating boiler that comprises a water magazine having a circular inner shell and flanges or profiles which define flue-gas channels inwardly of the shell, as described above. Theunit 31 may be used conveniently to replace other combustion chamber arrangements fitted in such heating boilers. - Thus, the aforedescribed arrangements operate in a manner which is highly satisfactory from an environmental point of view, since the NOX content can be kept very low (<120 mg/kWh). The arrangements involved are extremely simple mechanical constructions which can be produced simply and cheaply. The arrangements are also easy handle from a servicing aspect. When cleaning the unit, the
outer wall 25 is removed and thecombustion chamber unit 31 withdrawn from the boiler. When servicing or cleaning is completed, theunit 31 is simply inserted into the boiler and the boiler is then again operative.
Claims (9)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9203460 | 1992-11-18 | ||
SE9203460A SE500326C2 (en) | 1992-11-18 | 1992-11-18 | Heating boiler with flue gas return and combustion chamber unit for such boiler |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0598691A1 true EP0598691A1 (en) | 1994-05-25 |
EP0598691B1 EP0598691B1 (en) | 1997-07-16 |
Family
ID=20387853
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP93850219A Expired - Lifetime EP0598691B1 (en) | 1992-11-18 | 1993-11-17 | A heating boiler with flue-gas recirculation |
Country Status (4)
Country | Link |
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EP (1) | EP0598691B1 (en) |
AT (1) | ATE155568T1 (en) |
DE (1) | DE69312226T2 (en) |
SE (1) | SE500326C2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0684432A1 (en) * | 1994-05-27 | 1995-11-29 | VIESSMANN WERKE GmbH & CO. | Three pars boiler |
ITMI20112023A1 (en) * | 2011-11-08 | 2013-05-09 | Milano Politecnico | BOILER WITHOUT FLAME FOR THE PRODUCTION OF HOT WATER |
CN107581229A (en) * | 2017-10-27 | 2018-01-16 | 四川科达节能设备有限公司 | Fluid fuel safety normal-pressure energy-saving heat preserving scalds pig stove |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020102847A1 (en) * | 2018-11-22 | 2020-05-28 | Rheem Australia Pty Limited | An improved liquid heater |
DE102020121934B3 (en) * | 2020-08-21 | 2021-05-20 | Viessmann Werke Gmbh & Co Kg | Gas burner device and method for operating a gas burner device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3048044C2 (en) * | 1980-12-19 | 1983-06-09 | Helmut Dipl.-Chem. 8000 München Ulrich | Flame tube made of heat-resistant material for burners, especially oil burners |
EP0166703A2 (en) * | 1984-03-30 | 1986-01-02 | Enertech Värme Aktiebolag | Heater |
DE3738623C1 (en) * | 1987-11-11 | 1989-02-02 | Wolf Klimatechnik Gmbh | Heating furnace with flue gas recirculation |
EP0428117A2 (en) * | 1989-11-16 | 1991-05-22 | VIESSMANN WERKE GmbH & CO. | Boiler with exhaust gas recirculation to the burner |
DE4035262A1 (en) * | 1990-11-03 | 1992-05-07 | Sbs B Schmidt Gmbh & Co | Low temp. heating boiler for liq. or gas fuel - has circular water jacket surrounding combustion chamber with exhaust retaining chamber and exhaust outlet chamber |
-
1992
- 1992-11-18 SE SE9203460A patent/SE500326C2/en unknown
-
1993
- 1993-11-17 EP EP93850219A patent/EP0598691B1/en not_active Expired - Lifetime
- 1993-11-17 DE DE69312226T patent/DE69312226T2/en not_active Expired - Fee Related
- 1993-11-17 AT AT93850219T patent/ATE155568T1/en not_active IP Right Cessation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3048044C2 (en) * | 1980-12-19 | 1983-06-09 | Helmut Dipl.-Chem. 8000 München Ulrich | Flame tube made of heat-resistant material for burners, especially oil burners |
EP0166703A2 (en) * | 1984-03-30 | 1986-01-02 | Enertech Värme Aktiebolag | Heater |
DE3738623C1 (en) * | 1987-11-11 | 1989-02-02 | Wolf Klimatechnik Gmbh | Heating furnace with flue gas recirculation |
EP0428117A2 (en) * | 1989-11-16 | 1991-05-22 | VIESSMANN WERKE GmbH & CO. | Boiler with exhaust gas recirculation to the burner |
DE4035262A1 (en) * | 1990-11-03 | 1992-05-07 | Sbs B Schmidt Gmbh & Co | Low temp. heating boiler for liq. or gas fuel - has circular water jacket surrounding combustion chamber with exhaust retaining chamber and exhaust outlet chamber |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0684432A1 (en) * | 1994-05-27 | 1995-11-29 | VIESSMANN WERKE GmbH & CO. | Three pars boiler |
ITMI20112023A1 (en) * | 2011-11-08 | 2013-05-09 | Milano Politecnico | BOILER WITHOUT FLAME FOR THE PRODUCTION OF HOT WATER |
EP2592362A1 (en) * | 2011-11-08 | 2013-05-15 | Politecnico Di Milano | Flameless boiler for producing hot water |
CN107581229A (en) * | 2017-10-27 | 2018-01-16 | 四川科达节能设备有限公司 | Fluid fuel safety normal-pressure energy-saving heat preserving scalds pig stove |
Also Published As
Publication number | Publication date |
---|---|
SE500326C2 (en) | 1994-06-06 |
SE9203460D0 (en) | 1992-11-18 |
ATE155568T1 (en) | 1997-08-15 |
SE9203460L (en) | 1994-05-19 |
DE69312226T2 (en) | 1997-11-13 |
DE69312226D1 (en) | 1997-08-21 |
EP0598691B1 (en) | 1997-07-16 |
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