EP0194421A2 - Boiler for a low-temperature heating - Google Patents

Boiler for a low-temperature heating Download PDF

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Publication number
EP0194421A2
EP0194421A2 EP86100865A EP86100865A EP0194421A2 EP 0194421 A2 EP0194421 A2 EP 0194421A2 EP 86100865 A EP86100865 A EP 86100865A EP 86100865 A EP86100865 A EP 86100865A EP 0194421 A2 EP0194421 A2 EP 0194421A2
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EP
European Patent Office
Prior art keywords
flue gas
water jacket
flue
boiler
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.)
Withdrawn
Application number
EP86100865A
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German (de)
French (fr)
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EP0194421A3 (en
Inventor
Friedhelm Salzmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Deutsche Babcock AG
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Deutsche Babcock AG
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Filing date
Publication date
Application filed by Deutsche Babcock AG filed Critical Deutsche Babcock AG
Publication of EP0194421A2 publication Critical patent/EP0194421A2/en
Publication of EP0194421A3 publication Critical patent/EP0194421A3/en
Withdrawn legal-status Critical Current

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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
    • F24H1/28—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 including one or more furnace or fire tubes
    • F24H1/282—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 including one or more furnace or fire tubes with flue gas passages built-up by coaxial water mantles

Definitions

  • the invention relates to a boiler for low-temperature heating with the features of the preamble of claim 1.
  • the invention has for its object to provide a boiler of the generic type in such a way that the problems occurring at low flow and return temperatures are easy to master.
  • the invention is based on the consideration that condensation of condensable constituents of the flue gas by cooling on the relatively cold surface the water jacket only occurs in a laminar flow.
  • the flue gas flues are designed so that a laminar flow does not occur and for this reason the heat exchanger surfaces remain dry. This applies in particular to the zone at the end of the boiler in the area of the flue gas outlet. In this way, low surface temperatures can be permitted on the water jackets without the need to use corrosion-resistant coatings or materials.
  • the drawing shows schematically the longitudinal section through a boiler according to the invention.
  • the boiler used for low-temperature heating has an outer water jacket 1.
  • the outer water jacket 1 is provided with a nozzle 2 for the flow and a nozzle 3 for the return, which are connected to the heating system.
  • the connector 3 for the return is provided on the top of the boiler in order to prevent the water content of the water jacket 1 from being stratified with colder water at the desired low flow temperature.
  • the outer jacket 1 is connected by a base plate 4, while a burner (not shown) can be connected to the front.
  • the outer water jacket 1 encloses a combustion chamber 5 and an inner water jacket 6, which are arranged coaxially one behind the other.
  • the water jackets 1, 6 are connected to one another on the water side by connecting pieces 7.
  • a partition 8 is arranged within the inner water jacket 6 and separates its interior from the combustion chamber 5.
  • the partition 8 is removably arranged and thermally insulated.
  • an annular, first flue gas duct 9 is formed, which connects the combustion chamber 5 with the space between the base plate 4 and the rear end wall of the inner water jacket 6.
  • an exhaust pipe 10 is inserted into the inner water jacket 6, which penetrates the base plate 4 and extends into the vicinity of the separating plate 8.
  • An annular, second flue gas flue 11 is formed between the exhaust pipe 10 and the inner jacket 6.
  • the cross section of this second flue gas flue 11 is smaller than the cross section of the first flue gas flue 9 in order to take into account the volume reduction of the exhaust gases due to the cooling.
  • the cross sections of the two flue gas flues 9, 11 are dimensioned so closely that the speed of the flue gases is increased so far that a turbulent flow prevails in the boundary layer region between the flue gases and the surface of the water jackets 1, 6.
  • the absolute size of the cross sections calculated from the well-known laws of Strömun g s teaching for the minimum expected amounts of flue gas per unit of time.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Incineration Of Waste (AREA)
  • Chimneys And Flues (AREA)

Abstract

The boiler is provided with two water jackets (1, 6), between which a first smoke gas flue (9) is formed. Inserted into the inner space of the inner water jacket (6), which is separated from the combustion chamber (5), is a waste gas pipe (10), a second smoke gas flue (11) being formed between the waste gas pipe (10) and the inner water jacket (6). The cross-section of the smoke gas flues (9, 11) is dimensioned in such a manner that smoke gas speeds of such a magnitude are established that a turbulent flow prevails in the region close to the wall.

Description

Die Erfindung betrifft einen Heizkessel für eine Niedertemperaturheizung mit den Merkmalen des Oberbegriffes des Anspruches 1.The invention relates to a boiler for low-temperature heating with the features of the preamble of claim 1.

Wenn derartige Heizkessel mit einer niedrigen Vorlauf-und Rücklauftemperatur betrieben werden, besteht die Gefahr, daß Bestandteile aus dem Rauchgas an den Wärmetauscherflächen kondensieren. Die Kondensate führen zu Korrosionsschäden an den Wärmetauscherflächen. Wird weiterhin ein solcher Heizkessel nach einer Periode niedriger Wärmebeaufschlagung stärker beheizt, so stört das zeitweilig angefallene Kondensat den einsetzenden stärkeren Verbrennungsvorgang durch Verdampfung.If such boilers are operated with a low flow and return temperature, there is a risk that constituents from the flue gas will condense on the heat exchanger surfaces. The condensates cause corrosion damage to the heat exchanger surfaces. If such a boiler is heated more strongly after a period of low heat, the condensate temporarily interferes with the onset of stronger combustion by evaporation.

Es ist bekannt, die Oberfläche der Wassermäntel auf der Rauchgasseite mit einem korrosionsfesten Überzug zu versehen. Die unterschiedliche Wärmedehnung der Wand der Wassermäntel und des Überzuges führt jedoch zu Haarrissen in dem Überzug, so daß ein wirksamer Schutz der Wärmetauscherflächen nicht mehr vorhanden ist. Die Verwendung von korrosionsbeständigen Werkstoffen für die Wärmetauscherflächen würde den Heizkessel erheblich verteuern.It is known to provide the surface of the water jacket on the flue gas side with a corrosion-resistant coating. The different thermal expansion of the wall of the water jacket and the coating, however, leads to hairline cracks in the coating, so that effective protection of the heat exchanger surfaces is no longer available. The use of corrosion-resistant materials for the heat exchanger surfaces would make the boiler considerably more expensive.

Der Erfindung liegt die Aufgabe zugrunde, einen Heizkessel der gattungsgemäßen Art derart auszubilden, daß die bei niedrigen Vorlauf- und Rücklauf temperaturen auftretenden Probleme in einfacher Weise zu beherrschen sind.The invention has for its object to provide a boiler of the generic type in such a way that the problems occurring at low flow and return temperatures are easy to master.

Diese Aufgabe wird bei einem gattungsgemäßen Heizkessel erfindungsgemäß durch die kennzeichnenden Merkmale des Anspruches 1 gelöst. Vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen angegeben.This object is achieved in a generic boiler according to the invention by the characterizing features of claim 1. Advantageous embodiments of the invention are specified in the subclaims.

Die Erfindung geht von der Überlegung aus, daß eine Kondensation von kondensierbaren Bestandteilen des Rauchgases durch Abkühlung an der verhältnismäßig kalten Oberfläche der Wassermäntel nur bei einer laminaren Strömung auftritt. Gemäß der Erfindung sind die Rauchgaszüge so ausgebildet, daß eine laminare Strömung nicht auftritt und daß aus diesem Grund die Wärmetauscherflächen trocken bleiben. Das gilt insbesondere für die Zone am Kesselende im Bereich des Rauchgasaustrittes. Auf diese Weise können niedrige Oberflächentemperaturen an den Wassermänteln zugelassen werden, ohne daß korrosionsbeständige überzüge oder Werkstoffe verwendet werden müssen.The invention is based on the consideration that condensation of condensable constituents of the flue gas by cooling on the relatively cold surface the water jacket only occurs in a laminar flow. According to the invention, the flue gas flues are designed so that a laminar flow does not occur and for this reason the heat exchanger surfaces remain dry. This applies in particular to the zone at the end of the boiler in the area of the flue gas outlet. In this way, low surface temperatures can be permitted on the water jackets without the need to use corrosion-resistant coatings or materials.

Es ist an sich bekannt, die Wärmetauscherflächen außen mit Rippen zu versehen, um auf der dem Rauchgas zugewandten Seite hohe Oberflächentemperaturen zu erreichen. Durch diese Maßnahmen kann jedoch das Kesselende nicht beeinflußt werden, so daß dort weiterhin die Gefahr einer Kondensation bestehen bleibt.It is known per se to provide the outside of the heat exchanger surfaces with ribs in order to achieve high surface temperatures on the side facing the flue gas. However, the boiler end cannot be influenced by these measures, so that there is still the risk of condensation.

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und wird im folgenden näher erläutert. Die Zeichnung gibt schematisch den Längsschnitt durch einen Heizkessel gemäß der Erfindung wieder.An embodiment of the invention is shown in the drawing and is explained in more detail below. The drawing shows schematically the longitudinal section through a boiler according to the invention.

Der für Niedertemperaturheizungen verwendete Heizkessel weist einen äußeren Wassermantel 1 auf. Der äußere Wassermantel 1 ist mit einem Stutzen 2 für den Vorlauf und einen Stutzen 3 für den Rücklauf versehen, die an das Heizungssystem angeschlossen sind. Der Stutzen 3 für den Rücklauf ist an der Oberseite des Heizkessels vorgesehen, um bei der angestrebten niedrigen Vorlauftemperatur eine Unterschichtung des Wasserinhalts des Wassermantels 1 mit kälteren Wasser zu vermeiden. Auf seiner Rückseite ist der äußere Mantel 1 durch eine Bodenplatte 4 angeschlossen, während an die Vorderseite ein nicht dargestellter Brenner anschließbar ist.The boiler used for low-temperature heating has an outer water jacket 1. The outer water jacket 1 is provided with a nozzle 2 for the flow and a nozzle 3 for the return, which are connected to the heating system. The connector 3 for the return is provided on the top of the boiler in order to prevent the water content of the water jacket 1 from being stratified with colder water at the desired low flow temperature. On its back, the outer jacket 1 is connected by a base plate 4, while a burner (not shown) can be connected to the front.

Der äußere Wassermantel 1 umschließt einen Brennraum 5 und einen inneren Wassermantel 6, die koaxial hintereinander angeordnet sind. Die Wassermäntel 1, 6 sind wasserseitig durch Verbindungsstücke 7 miteinander verbunden. Innerhalb des inneren Wassermantels 6 ist eine Trennwand 8 angeordnet, die dessen Innenraum von dem Brennraum 5 abtrennt. Die Trennwand 8 ist herausnehmbar angeordnet und thermisch isoliert.The outer water jacket 1 encloses a combustion chamber 5 and an inner water jacket 6, which are arranged coaxially one behind the other. The water jackets 1, 6 are connected to one another on the water side by connecting pieces 7. A partition 8 is arranged within the inner water jacket 6 and separates its interior from the combustion chamber 5. The partition 8 is removably arranged and thermally insulated.

Zwischen dem äußeren und dem inneren Wassermantel 1, 6 ist ein ringförmiger, erster Rauchgaszug 9 gebildet, der den Brennraum 5 mit dem Raum zwischen der Bodenplatte 4 und der rückwärtigen Stirnwand des inneren Wassermantels 6 verbindet. Auf der dem Brennraum 5 abgewandten Seite ist in den inneren Wassermantel 6 ein Abgasrohr 10 eingesetzt, das die Bodenplatte 4 durchdringt und bis in die Nähe der Trennplatte 8 reicht. Das Abgasrohr 10, durch das die Abgase mit einer bei Heizkesseln üblichen Temperatur von etwa 1600 C austreten, ist einen Kamin angeschlossen.Between the outer and the inner water jacket 1, 6, an annular, first flue gas duct 9 is formed, which connects the combustion chamber 5 with the space between the base plate 4 and the rear end wall of the inner water jacket 6. On the side facing away from the combustion chamber 5, an exhaust pipe 10 is inserted into the inner water jacket 6, which penetrates the base plate 4 and extends into the vicinity of the separating plate 8. The exhaust pipe 10 through which the exhaust gases exit with a conventional boilers at temperature of about 160 0 C, is connected a fireplace.

Zwischen dem Abgasrohr 10 und dem inneren Mantel 6 ist ein ringförmiger, zweiter Rauchgaszug 11 gebildet. Der Querschnitt dieses zweiten Rauchgaszuges 11 ist geringer als der Querschnitt des ersten Rauchgaszuges 9, um der durch die Abkühlung bedingten Volumenverminderung der Abgase Rechnung zu tragen. Die Querschnitte der beiden Rauchgaszüge 9, 11 sind so eng bemessen, daß die Geschwindigkeit der Rauchgase so weit angehoben wird, daß im Grenzschichtbereich zwischen den Rauchgasen und der Oberfläche der Wassermäntel 1, 6 eine turbulente Strömung vorherrscht. Die absolute Größe der Querschnitte errechnet sich aus den allgemein bekannten Gesetzen der Strömungs-lehre für die minimal zu erwartenden Rauchgasmengen pro Zeiteinheit.An annular, second flue gas flue 11 is formed between the exhaust pipe 10 and the inner jacket 6. The cross section of this second flue gas flue 11 is smaller than the cross section of the first flue gas flue 9 in order to take into account the volume reduction of the exhaust gases due to the cooling. The cross sections of the two flue gas flues 9, 11 are dimensioned so closely that the speed of the flue gases is increased so far that a turbulent flow prevails in the boundary layer region between the flue gases and the surface of the water jackets 1, 6. The absolute size of the cross sections calculated from the well-known laws of Strömun g s teaching for the minimum expected amounts of flue gas per unit of time.

Claims (4)

1. Heizkessel für eine Niedertemperaturheizung mit einem durch eine rückwärtige Wand (8) geschlossenen Brennraum (5) und mit zwei von Heizwasser durchflossenen Wassermänteln (1, 6) zwischen denen ein ringförmiger Rauchgaszug (9) gebildet ist, dadurch gekennzeichnet , daß von der dem Brennraum (5) abgewandten Seite in den inneren Wassermantel (6) ein Abgasrohr (10) eingesetzt ist, daß zwischen dem inneren Wassermantel (6) und dem Rauchgasrohr (10) ein weiterer Rauchgaszug (11) gebildet ist und daß der Querschnitt der Rauchgaszüge (9, 11) so bemessenist, daß sich Rauchgasgeschwindigkeiten von solcher Höhe einstellen, daß im wandnahen Bereich eine turbulente Strömung vorherrscht.1. Boiler for a low temperature heating with a through a rear wall (8) closed combustion chamber (5) and with two water jackets through which heating water flows (1, 6) between which an annular flue gas flue (9) is formed, characterized in that the An exhaust pipe (10) is inserted into the inner water jacket (6) facing away from the combustion chamber (5), that a further flue gas flue (11) is formed between the inner water jacket (6) and the flue gas pipe (10) and that the cross section of the flue gas flues ( 9, 11) is dimensioned such that flue gas speeds of such a height occur that a turbulent flow prevails in the area near the wall. 2. Heizkessel nach Anspruch 1, dadurch gekennzeichnet, daß der Querschnitt des zweiten Rauchgaszuges (11) geringer ist als der des ersten Rauchgaszuges (9).2. Boiler according to claim 1, characterized in that the cross section of the second flue gas flue (11) is smaller than that of the first flue gas flue (9). 3. Heizkessel nach Anspruch 1 oder 2, dadurch gekennzeichnet , daß der Brennraum (5) und der innere Wassermantel (6) innerhalb des äußeren Wassermantels (1) koaxial hintereinander angeordnet und durch die Trennwand (8) voneinander getrennt sind.3. Boiler according to claim 1 or 2, characterized in that the combustion chamber (5) and the inner water jacket (6) within the outer water jacket (1) are arranged coaxially one behind the other and separated by the partition (8). 4. Heizkessel nach Anspruch 3, dadurch gekennzeichnet, daß die Trennwand (8) herausnehmbar angeordnet und thermisch isoliert ist.4. Boiler according to claim 3, characterized in that the partition (8) is removably arranged and thermally insulated.
EP86100865A 1985-03-07 1986-01-23 Boiler for a low-temperature heating Withdrawn EP0194421A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853508117 DE3508117A1 (en) 1985-03-07 1985-03-07 BOILER FOR A LOW TEMPERATURE HEATING
DE3508117 1985-03-07

Publications (2)

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EP0194421A2 true EP0194421A2 (en) 1986-09-17
EP0194421A3 EP0194421A3 (en) 1988-08-03

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EP86100865A Withdrawn EP0194421A3 (en) 1985-03-07 1986-01-23 Boiler for a low-temperature heating

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DE (1) DE3508117A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3640503C1 (en) * 1986-11-27 1988-03-24 Babcock Werke Ag Boiler for a low temperature heating
DE9013666U1 (en) * 1990-09-29 1992-01-30 August Broetje Gmbh & Co, 2902 Rastede, De

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD154308A1 (en) * 1980-11-11 1982-03-10 Udo Becher WATER HEATER WITH CYLINDRICAL FIREPLACE FOR GASIFIED SOLID FUELS
DE3116992A1 (en) * 1981-04-29 1982-11-18 Buderus Ag, 6330 Wetzlar Central heating boiler

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD154308A1 (en) * 1980-11-11 1982-03-10 Udo Becher WATER HEATER WITH CYLINDRICAL FIREPLACE FOR GASIFIED SOLID FUELS
DE3116992A1 (en) * 1981-04-29 1982-11-18 Buderus Ag, 6330 Wetzlar Central heating boiler

Also Published As

Publication number Publication date
EP0194421A3 (en) 1988-08-03
DE3508117A1 (en) 1986-09-11

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