EP0281823A2 - Power regulation device for fuel-fired heat producers - Google Patents

Power regulation device for fuel-fired heat producers Download PDF

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Publication number
EP0281823A2
EP0281823A2 EP88102494A EP88102494A EP0281823A2 EP 0281823 A2 EP0281823 A2 EP 0281823A2 EP 88102494 A EP88102494 A EP 88102494A EP 88102494 A EP88102494 A EP 88102494A EP 0281823 A2 EP0281823 A2 EP 0281823A2
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EP
European Patent Office
Prior art keywords
fuel
air
main line
ratio
heat
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Withdrawn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
EP88102494A
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German (de)
French (fr)
Other versions
EP0281823A3 (en
Inventor
Alfred Sinner
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.)
Karl Dungs GmbH and Co KG
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Karl Dungs GmbH and Co KG
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Publication date
Application filed by Karl Dungs GmbH and Co KG filed Critical Karl Dungs GmbH and Co KG
Publication of EP0281823A2 publication Critical patent/EP0281823A2/en
Publication of EP0281823A3 publication Critical patent/EP0281823A3/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N1/00—Regulating fuel supply
    • F23N1/02—Regulating fuel supply conjointly with air supply
    • F23N1/022—Regulating fuel supply conjointly with air supply using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N1/00—Regulating fuel supply
    • F23N1/06—Regulating fuel supply conjointly with draught
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/18—Systems for controlling combustion using detectors sensitive to rate of flow of air or fuel
    • F23N2005/181—Systems for controlling combustion using detectors sensitive to rate of flow of air or fuel using detectors sensitive to rate of flow of air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/18—Systems for controlling combustion using detectors sensitive to rate of flow of air or fuel
    • F23N2005/185—Systems for controlling combustion using detectors sensitive to rate of flow of air or fuel using detectors sensitive to rate of flow of fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2221/00—Pretreatment or prehandling
    • F23N2221/06—Preheating gaseous fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2225/00—Measuring
    • F23N2225/08—Measuring temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2225/00—Measuring
    • F23N2225/08—Measuring temperature
    • F23N2225/13—Measuring temperature outdoor temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2233/00—Ventilators
    • F23N2233/02—Ventilators in stacks
    • F23N2233/04—Ventilators in stacks with variable speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2235/00—Valves, nozzles or pumps
    • F23N2235/12—Fuel valves
    • F23N2235/16—Fuel valves variable flow or proportional valves

Definitions

  • the invention relates to a device for regulating the output of fuel-fired, in particular gas-fired, heat generators, comprising a burner, a main line connecting the burner with an air inlet opening, a flow sensor arranged in the main line, and a fuel line opening in the main line in the region between the flow sensor and the burner which is supplied to the main line with a predetermined, constant amount of fuel, a fan which is operatively connected to the main line and which determines the air flow rate in the main line and a the delivery rate of the fan in Dependency on the output signal of the flow sensor and possibly further control device controlling the variables influencing the optimal fuel / air ratio.
  • a heat generator using gas as a fuel with such a device is described in a brochure no. 1.23.202320 from Karl Dungs GmbH & Co., Schorndorf.
  • Such a heat generator can be optimally set for a given heating output by firmly specifying the amount of fuel required to achieve this heating output and supplying the air required for optimal combustion in a controlled manner.
  • the air supply is regulated with the aid of the blower, the output of which is controlled in such a way that the air speed determined by the flow sensor is kept at a predetermined value, which is determined by the control device as a function of variables influencing the amount of air supplied, in particular as a function of the air temperature. can be changed.
  • the known device has the advantage that it does not require complicated control loops in order to change the amount of fuel supplied when the heating power changes and to provide the optimum amount of air for the respective amount of fuel. Rather, if a reduced heating capacity is required, it is sufficient to periodically switch the burner control on and off, as is generally the case in central heating systems. With such burner controls, the nominal output is normally set to the maximum heating requirement of the central heating system. With central heating systems for single-family houses, flats and the like, the heat requirement is not very high, especially Thermal insulation measures are increasingly being used which greatly reduce the heat requirement.
  • the burner controls of such central heating systems are not only used for heating the living rooms, but also for hot water preparation.
  • the heat requirement for hot water preparation is much greater than for the actual heating, if not very large hot water storage facilities are provided and no sensitive shortage of hot water is to be accepted.
  • the burning time of the heat generator is as long as possible, so that the instantaneous heat output does not significantly exceed the respective heat requirement.
  • a change in the heat output by increasing the amount of fuel supplied to the main line while increasing the amount of air supplied would, however, require difficult control processes, because even with slight deviations from the respectively optimal mixing ratio of fuel and air, pollutants develop and ultimately suffocate or tear off Flames and thus the burner may go out, which would have the consequence that the burner would malfunction and would only have to be restarted by hand.
  • the user of a power-controlled heat generator wants to be able to rely on the fact that his device works trouble-free and does not interfere with changes in the operating conditions, such as with strong changes in the outside temperature, but especially when hot water is drawn.
  • the invention has for its object to develop a device of the type mentioned so that it can be adjusted to different heating capacities depending on the respective heat requirements, without losing the optimal setting of the combustion conditions and without complicated control devices required to maintain these optimal conditions are.
  • a heat exchanger is arranged in the main line in front of the flow sensor, which is switched on in the fuel line, that a throttle valve for adjusting the fuel throughput and a flow sensor are arranged behind this throttle valve and the heat exchanger and that the control device is designed to adjust the air throughput to a constant ratio of the flow velocity of gas and air.
  • the quantity of fuel that can be adjusted to the respective heating requirement with the help of the throttle valve is used as a reference variable, which the air quantity is always tracked in the correct ratio by keeping the flow rates of fuel and air in the corresponding lines in a constant ratio. It is then easily possible to change this ratio depending on environmental conditions, in particular on air temperature and humidity, in order to always maintain optimal conditions.
  • the throttle valve for adjusting the fuel throughput in the fuel line upstream of the heat exchanger, in which the fuel can be exposed to strong temperature changes due to the adaptation to the air temperature.
  • the throttle valve can be controlled by variables influencing the heating power, in particular by the room temperature, the flow temperature of a hot water central heating system, the temperature in the reservoir of a system for hot water preparation and the like.
  • the invention is described and explained in more detail below with reference to the embodiment shown in the drawing.
  • the features that can be gathered from the description and the drawing can be used individually or in any combination in other embodiments of the invention.
  • the drawing shows a schematic representation of a heat generator with a device for power control designed according to the invention.
  • the heat generator shown in the drawing has a burner 1, to which a gas / air mixture is supplied via a main line 2.
  • the burner 1 is located within a boiler housing 3, which also encloses the heat exchanger 4 of a heating system.
  • the boiler housing 3 is provided with a vent 5 for the flue gases, in which there is a fan 7 driven by a motor 6.
  • the main line 2 connects the burner 1 to an air inlet opening 8.
  • a temperature sensor 9 and a flow sensor 10 also protrude into the main line. The output signals of these sensors 9, 10 are fed to a control device 11.
  • a fuel line 13 opens into the main line 2 and supplies gas to the main line as fuel.
  • a gas pressure regulator 14 and a throttle valve 15 are located in the fuel line 13 in the flow direction of the gas, which cause a predetermined amount of gas to be supplied to the main line.
  • a heat exchanger 16 switched into the fuel line 3, which is designed as a coil in the illustrated embodiment. Since the heat exchanger 16 is traversed by the air supplied through the main line 2, heat exchange takes place between the gas and the air, with the result that the gas at the outlet of the heat exchanger 16 has the same temperature as the air supplied to the burner 1. Behind the heat exchanger 16 there is a further flow sensor 17 in the line 13, the output signal of which is also fed to the control device 11.
  • the control device 11 is designed such that it controls the speed of the motor used to drive the blower 7 in such a way that the value supplied by the flow sensor 9 arranged in the main line 2 is always in a predetermined ratio to that of the flow sensor 17 in FIG Fuel line 13 delivered value is.
  • control device 11 makes it possible to change the amount of gas supplied to the burner 1 via the fuel line 13 and thus to change the heating output of the burner as desired, because the control device 11 always ensures that the air is always in the correct manner via the main line 2 Ratio is fed.
  • control device 11 varies this predetermined ratio as a function of various influencing variables, in particular as a function of the temperature, which is determined by the temperature sensor 9.
  • a further influencing variable could, for example, be the relative air humidity determined by a sensor (not shown in more detail).
  • throttle valve 15 serves this purpose, the position of which is controlled by a gas regulator 21, which responds to signals supplied by sensors 22.
  • sensors 22 can in particular be thermal sensors which monitor the outside temperature, the room temperature and / or the flow temperature of the heating water in central heating systems and the water temperature in a storage boiler in systems for hot water preparation.
  • shut-off valve 24 can also be located in the line 13 upstream of the flow sensor 17. Shutting off the fuel line 13 has the result that the output signal of the flow sensor 17 indicates the absence of a gas flow, whereupon the control device 11 can also switch off the delivery of air by the engine 6.
  • the invention is not limited to the exemplary embodiment shown, but deviations from it are possible without the scope of the invention leave.
  • the heat exchanger is to be selected from the point of view that temperature balancing between these two substances occurs essentially at all flow rates of air and fuel occurring during operation of the system, i.e. the fuel temperature essentially adjusts to the air temperature in view of the very small amount of fuel.
  • the heat exchanger 16 for the fuel must fit into the air supply main line 2 and should not increase the flow resistance for gas and air excessively, so that on the one hand the gas pressure is sufficient to supply the main line 2 with the necessary amount of gas and on the other hand no blower 7 of excessive power application must find to promote the required amount of air.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Regulation And Control Of Combustion (AREA)

Abstract

With a view to optimum fuel utilisation and the reduction of harmful emissions, fuel-fired heat producers must work with a fuel/air ratio to be kept within narrow limits. This optimum ratio can be observed in a heat producer working with constant heating capacity in that a temporally constant quantity of fuel is added to a regulated quantity of air, the flow rate of which is adjusted in the main pipe leading to the burner by means of a blower supplying air. The disadvantage of such a heat producer is that it works with constant heating capacity. There is, however, a requirement for heat producers, the heating capacity of which can be changed, while retaining a very simple regulating device. A change in the heating capacity, while maintaining the optimum fuel/air ratio, can be achieved simply in that, using a heat exchanger (16) arranged in the air pipe (2), the fuel is brought to the same temperature as the air, so that measurement of the flow rates of air and fuel by means of flow sensors (10, 17) in the air pipe (2) and the gas pipe (13) allows an accurate determination of the ratio of gas and air quantities and thus also precise observance of this ratio. Regulation of the heating capacity can then also be achieved simply by changing the quantity of fuel supplied which is matched to the correct air quantity.

Description

Die Erfindung betrifft eine Einrichtung zur Leistungsrege­lung von brennstoffbefeuerten, insbesondere gasbefeuerten Wärmeerzeugern, mit einem Brenner, einer den Brenner mit einer Lufteintrittsöffnung verbindenden Hauptleitung, einem in der Hauptleitung angeordneten Strömungssensor, einer in der Hauptleitung im Bereich zwischen dem Strömungssensor und dem Brenner mündenden Brennstoffleitung, über die der Haupt­leitung eine vorgegebene, zeitlich konstante Brennstoffmenge zugeführt wird, einem mit der Hauptleitung in Wirkverbindung stehenden, den Luftdurchsatz in der Hauptleitung bestimmen­den Gebläse und einer die Förderleistung des Gebläses in Abhängigkeit von dem Ausgangssignal des Strömungssensors und gegebenenfalls weiteren, das optimale Brennstoff/Luft-Ver­hältnis beeinflussenden Größen steuerenden Regeleinrich­tung.The invention relates to a device for regulating the output of fuel-fired, in particular gas-fired, heat generators, comprising a burner, a main line connecting the burner with an air inlet opening, a flow sensor arranged in the main line, and a fuel line opening in the main line in the region between the flow sensor and the burner which is supplied to the main line with a predetermined, constant amount of fuel, a fan which is operatively connected to the main line and which determines the air flow rate in the main line and a the delivery rate of the fan in Dependency on the output signal of the flow sensor and possibly further control device controlling the variables influencing the optimal fuel / air ratio.

Ein mit Gas als Brennstoff arbeitender Wärmeerzeuger mit einer solchen Einrichtung ist in einem Prospekt Nr. 1.23.202320 der Firma Karl Dungs GmbH & Co., Schorndorf, beschrieben. Ein solcher Wärmeerzeuger läßt sich für eine vorgegebene Heizleistung optimal einstellen, indem die zum Erreichen dieser Heizleistung benötigte Brennstoffmenge fest vorgegeben und die zur optimalen Verbrennung benötigte Luft geregelt zugeführt wird. Die Regelung der Luftzufuhr erfolgt mit Hilfe des Gebläses, dessen Leistung so gesteuert wird, daß die von dem Strömungssensor ermittelte Luftgeschwindig­keit auf einem vorgegebenen Wert gehalten wird, der von der Regeleinrichtung in Abhängigkeit von die zugeführte Luftmen­ge beeinflussenden Größen, insbesondere in Abhängigkeit von der Lufttemperatur, verändert werden kann.A heat generator using gas as a fuel with such a device is described in a brochure no. 1.23.202320 from Karl Dungs GmbH & Co., Schorndorf. Such a heat generator can be optimally set for a given heating output by firmly specifying the amount of fuel required to achieve this heating output and supplying the air required for optimal combustion in a controlled manner. The air supply is regulated with the aid of the blower, the output of which is controlled in such a way that the air speed determined by the flow sensor is kept at a predetermined value, which is determined by the control device as a function of variables influencing the amount of air supplied, in particular as a function of the air temperature. can be changed.

Die bekannte Einrichtung hat den Vorteil, daß sie keine komplizierten Regelkreise benötigt, um bei sich ändernder Heizleistung die zugeführte Brennstoffmenge zu ändern und für die jeweilige Brennstoffmenge die optimale Luftmenge zur Verfügung zu stellen. Vielmehr genügt es, wenn eine vermin­derte Heizleistung gefordert wird, den Feuerungsautomaten periodisch an- und auszuschalten, wie es bei Zentralhei­zungsanlagen allgemein üblich ist. Bei solchen Feuerungs­automaten ist die Nennleistung normalerweise auf den maxima­len Wärmebedarf der Zentralheizungsanlage eingestellt. Bei Zentralheizungen von Einfamilienhäusern, Etagenwohnungen und dergleichen ist der Wärmebedarf nicht sehr hoch, zumal zunehmend wärmedämmende Maßnahmen Anwendung finden, die den Wärmebedarf stark vermindern.The known device has the advantage that it does not require complicated control loops in order to change the amount of fuel supplied when the heating power changes and to provide the optimum amount of air for the respective amount of fuel. Rather, if a reduced heating capacity is required, it is sufficient to periodically switch the burner control on and off, as is generally the case in central heating systems. With such burner controls, the nominal output is normally set to the maximum heating requirement of the central heating system. With central heating systems for single-family houses, flats and the like, the heat requirement is not very high, especially Thermal insulation measures are increasingly being used which greatly reduce the heat requirement.

Die Feuerungsautomaten solcher Zentralheizungen werden aber nicht nur zur Beheizung der Wohnräume verwendet, sondern auch zur Warmwasserbereitung. Der Wärmebedarf für die Warm­wasserbereitung ist sehr viel größer als für die eigentliche Beheizung, wenn nicht sehr große Warmwasser-Speichereinrich­tungen vorgesehen sind und kein empfindlicher Mangel an Warmwasser in Kauf genommen werden soll. Es wäre aber sehr unwirtschaftlich, den Feuerungsautomaten für eine Wärmelei­stung auszulegen, die unter normalen Heizbedingungen die für die Warmwasserbereitung erforderliche Wärmemenge liefern würde. Für die Wirtschaftlichkeit und für den Komfort einer Zentralheizungsanlage ist es nämlich von Bedeutung, daß die Brennzeit des Wärmeerzeugers möglichst groß ist, die augen­blickliche Wärmeleistung den jeweiligen Wärmebedarf also nicht wesentlich überschreitet. Eine Änderung der Wärme­leistung durch Erhöhen der der Hauptleitung zugeführten Brennstoffmenge bei gleichzeitiger Erhöhung der zugeführten Luftmenge würde jedoch schwierige Regelvorgänge erfordern, weil es schon bei geringen Abweichungen von dem jeweils optimalen Mischungsverhältnis von Brennstoff und Luft zur Entstehung von Schadstoffen und schließlich zu einem Er­sticken oder Abreißen der Flammen und damit zu einem Ausge­hen des Brenners kommen kann, was zur Folge hätte, daß der Brenner auf Störung ginge und erst wieder von Hand in Be­trieb genommen werden müßte. Der Benutzer eines leistungs­geregelten Wärmeerzeugers will sich jedoch darauf verlassen können, daß sein Gerät störungsfrei arbeitet und nicht bei Änderungen der Betriebszustände, wie beispielsweise bei starken Änderungen der Außentemperatur, insbesondere aber auch bei einer Heißwasser-Entnahme, auf Störung geht.The burner controls of such central heating systems are not only used for heating the living rooms, but also for hot water preparation. The heat requirement for hot water preparation is much greater than for the actual heating, if not very large hot water storage facilities are provided and no sensitive shortage of hot water is to be accepted. However, it would be very uneconomical to design the burner control for a heat output that would provide the amount of heat required for hot water preparation under normal heating conditions. For the economy and comfort of a central heating system it is important that the burning time of the heat generator is as long as possible, so that the instantaneous heat output does not significantly exceed the respective heat requirement. A change in the heat output by increasing the amount of fuel supplied to the main line while increasing the amount of air supplied would, however, require difficult control processes, because even with slight deviations from the respectively optimal mixing ratio of fuel and air, pollutants develop and ultimately suffocate or tear off Flames and thus the burner may go out, which would have the consequence that the burner would malfunction and would only have to be restarted by hand. The user of a power-controlled heat generator, however, wants to be able to rely on the fact that his device works trouble-free and does not interfere with changes in the operating conditions, such as with strong changes in the outside temperature, but especially when hot water is drawn.

Demgemäß liegt der Erfindung die Aufgabe zugrunde, eine Einrichtung der eingangs genannten Art so weiterzubilden, daß sie in Abhängigkeit von dem jeweiligen Wärmebedarf auf unterschiedliche Heizleistungen einstellbar ist, ohne daß die optimale Einstellung der Verbrennungsbedingungen ver­lorengeht und ohne daß zum Aufrechterhalten dieser optimalen Bedingungen komplizierte Regeleinrichtungen erforderlich sind.Accordingly, the invention has for its object to develop a device of the type mentioned so that it can be adjusted to different heating capacities depending on the respective heat requirements, without losing the optimal setting of the combustion conditions and without complicated control devices required to maintain these optimal conditions are.

Diese Aufgabe wird nach der Erfindung dadurch gelöst, daß in der Hauptleitung vor dem Strömungssensor ein Wärmeaustau­scher angeordnet ist, der in die Brennstoffleitung einge­schaltet ist, daß in der Brennstoffleitung ein Drosselventil zum Einstellen des Brennstoffdurchsatzes und hinter diesem Drosselventil und dem Wärmeaustauscher ein Strömungssensor angeordnet sind und daß die Regeleinrichtung dazu ausgebil­det ist, den Luftdurchsatz auf ein konstantes Verhältnis der Strömungsgeschwindigkeit von Gas und Luft einzustellen.This object is achieved according to the invention in that a heat exchanger is arranged in the main line in front of the flow sensor, which is switched on in the fuel line, that a throttle valve for adjusting the fuel throughput and a flow sensor are arranged behind this throttle valve and the heat exchanger and that the control device is designed to adjust the air throughput to a constant ratio of the flow velocity of gas and air.

Die oben erwähnten Schwierigkeiten bei der Regelung von Brennstoffmenge und Luftmenge entstehen nicht zuletzt da­durch, daß die Menge eines gasförmigen Stoffes nicht allein durch das Volumen, sondern in hohem Maße auch durch die Temperatur bestimmt wird. Dabei kann insbesondere die von außen zugeführte Verbrennungsluft sehr starken Schwankungen unterliegen. Nach der Erfindung werden diese Schwierigkeiten dadurch behoben, daß der insbesondere gasförmige Brennstoff durch einen Wärmeaustauscher geleitet wird, der in der die Verbrennungsluft führenden Hauptleitung angeordnet ist, mit dem Ergebnis, daß ein Temperaturausgleich stattfindet und der Brennstoff nach dem Verlassen des Wärmeaustauschers die gleiche Temperatur hat wie die die Hauptleitung durchströ­mende Luft, so daß die Luftmenge und die Gasmenge den Strö­mungsgeschwindigkeiten in der Hauptleitung bzw. der Brenn­stoffleitung streng proportional sind. Daher genügt es, den Luftdurchsatz so zu regeln, daß die Strömungsgeschwindigkeit der Luft stets in einem konstanten Verhältnis zur Strömungs­geschwindigkeit des Brennstoffes steht. Dabei wird die mit Hilfe des Drosselventils auf den jeweiligen Heizbedarf einstellbare Brennstoffmenge als Führungsgröße benutzt, der die Luftmenge stets im richtigen Verhältnis nachgeführt wird, indem die Strömungsgeschwindigkeiten von Brennstoff und Luft in den entsprechenden Leitungen in einem konstanten Verhältnis gehalten werden. Dabei besteht dann auch ohne weiteres die Möglichkeit, dieses Verhältnis in Abhängigkeit von Umweltbedingungen, insbesondere von Lufttemperatur und Luftfeuchtigkeit, zu ändern, um stets optimale Verhältnisse aufrechtzuerhalten.The above-mentioned difficulties in controlling the amount of fuel and the amount of air arise not least from the fact that the amount of a gaseous substance is determined not only by the volume, but also to a large extent by the temperature. In particular, the combustion air supplied from the outside can be subject to very strong fluctuations. According to the invention, these difficulties are overcome in that the gaseous fuel in particular is passed through a heat exchanger which is arranged in the main line carrying the combustion air, with the result that temperature compensation takes place and the fuel after leaving the heat exchanger has the same temperature as the air flowing through the main line, so that the amount of air and the amount of gas are strictly proportional to the flow rates in the main line and the fuel line. It is therefore sufficient to regulate the air throughput so that the flow rate of the air is always in constant proportion to the flow rate of the fuel. The quantity of fuel that can be adjusted to the respective heating requirement with the help of the throttle valve is used as a reference variable, which the air quantity is always tracked in the correct ratio by keeping the flow rates of fuel and air in the corresponding lines in a constant ratio. It is then easily possible to change this ratio depending on environmental conditions, in particular on air temperature and humidity, in order to always maintain optimal conditions.

Da die Temperatur des Brennstoffes im Gegensatz zur Lufttem­peratur gewöhnlich keinen großen Schwankungen unterliegt, ist es zweckmäßig, das Drosselventil zum Einstellen des Brennstoffdurchsatzes in der Brennstoffleitung vor dem Wärmeaustauscher anzuordnen, in dem der Brennstoff durch die Anpassung an die Lufttemperatur starken Temperaturänderungen ausgesetzt sein kann. Es liegen daher für das Drosselventil vor dem Wärmeaustauscher im wesentlichen gleichbleibende Artbeitsbedingungen vor, welche einen gleichmäßigeren Einfluß des Drosselventils gewährleisten. Das Drosselventil kann von die Heizleistung beeinflussenden Größen gesteuert sein, insbesondere von der Raumtemperatur, von der Vorlauftempera­tur einer Warmwasser-Zentralheizungsanlage, der Temperatur im Vorratsbehälter einer Anlage zur Warmwasserbereitung und dergleichen.Since the temperature of the fuel, in contrast to the air temperature, is usually not subject to large fluctuations, it is expedient to arrange the throttle valve for adjusting the fuel throughput in the fuel line upstream of the heat exchanger, in which the fuel can be exposed to strong temperature changes due to the adaptation to the air temperature. There are therefore essentially constant operating conditions for the throttle valve upstream of the heat exchanger, which ensure a more uniform influence of the throttle valve. The throttle valve can be controlled by variables influencing the heating power, in particular by the room temperature, the flow temperature of a hot water central heating system, the temperature in the reservoir of a system for hot water preparation and the like.

Die Erfindung wird im Folgenden anhand des in der Zeichnung dargestellten Ausführungsbeispieles näher beschrieben und erläutert. Die der Beschriebung und der Zeichnung zu entneh­menden Merkmale können bei anderen Ausführungsformen der Erfindung einzeln für sich oder in beliebiger Kombination Anwendung finden. Die Zeichnung zeigt eine schematische Darstellung eines Wärmeerzeugers mit einer nach der Erfin­dung ausgebildeten Einrichtung zur Leistungsregelung.The invention is described and explained in more detail below with reference to the embodiment shown in the drawing. The features that can be gathered from the description and the drawing can be used individually or in any combination in other embodiments of the invention. The drawing shows a schematic representation of a heat generator with a device for power control designed according to the invention.

Der in der Zeichnung dargestellte Wärmeerzeuger weist einen Brenner 1 auf, dem über eine Hauptleitung 2 ein Gas/Luft-­Gemisch zugeführt wird. Der Brenner 1 befindet sich inner­halb eines Kesselgehäuses 3, das auch den Wärmeaustauscher 4 einer Heizungsanlage umschließt. Das Kesselgehäuse 3 ist mit einem Abzug 5 für die Rauchgase versehen, in dem sich ein von einem Motor 6 angetriebenes Gebläse 7 befindet. Die Hauptleitung 2 verbindet den Brenner 1 mit einer Luftein­trittsöffnung 8. In die Hauptleitung ragen weiterhin ein Temperatursensor 9 und ein Strömungssensor 10 hinein. Die Ausgangssignale dieser Sensoren 9, 10 werden einer Regelein­richtung 11 zugeführt.The heat generator shown in the drawing has a burner 1, to which a gas / air mixture is supplied via a main line 2. The burner 1 is located within a boiler housing 3, which also encloses the heat exchanger 4 of a heating system. The boiler housing 3 is provided with a vent 5 for the flue gases, in which there is a fan 7 driven by a motor 6. The main line 2 connects the burner 1 to an air inlet opening 8. A temperature sensor 9 and a flow sensor 10 also protrude into the main line. The output signals of these sensors 9, 10 are fed to a control device 11.

Im Bereich zwischen den Sensoren 9, 10 und dem Brenner 1 mündet in die Hauptleitung 2 eine Brennstoffleitung 13, die der Hauptleitung als Brennstoff Gas zuführt. In der Brenn­stoffleitung 13 befinden sich in der Strömungsrichtung des Gases hintereinander ein Gasdruckeregler 14 und ein Drossel­ventil 15, die bewirken, daß der Hauptleitung eine vorgege­bene Gasmenge zugeführt wird. Bevor diese Gasmenge in die Hauptleitung 2 eintritt, wird sie durch einen in die Brenn­stoffleitung 3 eingeschalteten Wärmeaustauscher 16 geleitet, der bei dem dargestellten Ausführungsbeispiel als Rohr­schlange ausgebildet ist. Da der Wärmeaustauscher 16 von der durch die Hauptleitung 2 zugeführten Luft durchströmt wird, findet ein Wärmeaustausch zwischen dem Gas und der Luft statt, mit dem Ergebnis, daß am Ausgang des Wärmetauschers 16 das Gas die gleiche Temperatur hat wie die dem Brenner 1 zugeführte Luft. Hinter dem Wärmeaustauscher 16 befindet sich in der Leitung 13 ein weiterer Strömungssensor 17, dessen Ausgangssignal ebenfalls der Regeleinrichtung 11 zugeführt wird.In the area between the sensors 9, 10 and the burner 1, a fuel line 13 opens into the main line 2 and supplies gas to the main line as fuel. A gas pressure regulator 14 and a throttle valve 15 are located in the fuel line 13 in the flow direction of the gas, which cause a predetermined amount of gas to be supplied to the main line. Before this amount of gas enters the main line 2, it is passed through a heat exchanger 16 switched into the fuel line 3, which is designed as a coil in the illustrated embodiment. Since the heat exchanger 16 is traversed by the air supplied through the main line 2, heat exchange takes place between the gas and the air, with the result that the gas at the outlet of the heat exchanger 16 has the same temperature as the air supplied to the burner 1. Behind the heat exchanger 16 there is a further flow sensor 17 in the line 13, the output signal of which is also fed to the control device 11.

Da Gas und Luft die gleiche Temperatur haben, sind ihre dem Brenner 1 zugeführten Mengen den Strömungsgeschwindigkeiten in der Brennstoffleitung 13 bzw. der Hauptleitung 2 propor­tional, so daß die Strömungssensoren 17 und 9 ein genaues Maß für die dem Brenner 1 zugeführten Mengen liefern. Daher ist es ausreichend, zum Einhalten des für eine einwandfreie Verbrennung notwendigen Brennstoff/Luft-Verhältnisses ein konstantes Verhältnis der von den Strömungssensoren 9 und 17 erfaßten Strömungsgeschwindigkeiten von Gas und Luft in den Leitungen 13 und 2 einzuhalten. Die Regeleinrichtung 11 ist so ausgebildet, daß sie die Drehzahl des zum Antrieb des Gebläses 7 dienenden Motors in solcher Weise steuert, daß die von dem in der Hauptleitung 2 angeordneten Strömungssen­sor 9 gelieferte Wert stets in einem vorgegebenen Verhältnis zu dem von dem Strömungssensor 17 in der Brennstoffleitung 13 gelieferten Wert steht. Dadurch besteht die Möglichkeit, die über die Brennstoffleitung 13 dem Brenner 1 zugeführte Gasmenge und damit die Heizleistung des Brenners beliebig zu verändern, weil die Regeleinrichtung 11 stets dafür sorgt, daß über die Hauptleitung 2 die Luft stets in dem richtigen Verhältnis zugeführt wird. Darüber hinaus besteht die Mög­lichkeit, daß die Regeleinrichtung 11 dieses vorgegebene Verhältnis in Abhängigkeit von verschiedenen Einflußgrößen variiert, insbesondere in Abhängigkeit von der Temperatur, die von dem Temperatursensor 9 festgestellt wird. Eine weitere Einflußgröße könnte beispielsweise die von einem nicht näher dargestellten Sensor festgestellte, relative Luftfeuchtigkeit sein.Since gas and air are at the same temperature, their quantities supplied to the burner 1 are proportional to the flow velocities in the fuel line 13 and the main line 2, respectively, so that the flow sensors 17 and 9 provide an exact measure of the quantities supplied to the burner 1. It is therefore sufficient to maintain a constant ratio of the gas and air flow velocities detected by the flow sensors 9 and 17 in the lines 13 and 2 in order to maintain the fuel / air ratio necessary for perfect combustion. The control device 11 is designed such that it controls the speed of the motor used to drive the blower 7 in such a way that the value supplied by the flow sensor 9 arranged in the main line 2 is always in a predetermined ratio to that of the flow sensor 17 in FIG Fuel line 13 delivered value is. This makes it possible to change the amount of gas supplied to the burner 1 via the fuel line 13 and thus to change the heating output of the burner as desired, because the control device 11 always ensures that the air is always in the correct manner via the main line 2 Ratio is fed. In addition, there is the possibility that the control device 11 varies this predetermined ratio as a function of various influencing variables, in particular as a function of the temperature, which is determined by the temperature sensor 9. A further influencing variable could, for example, be the relative air humidity determined by a sensor (not shown in more detail).

Da die Luftmenge stets auf das richtighe Verhältnis zu der über die Leitung 13 zugeführten Gasmenge eingestellt wird, ist es möglich, diese Gasmenge entsprechend der jeweils gewünschten Heizleistung einzustellen. Diesem Zweck dient das bereits erwähnte Drosselventil 15, dessen Stellung von einem Gasregler 21 gesteuert wird, der auf von Sensoren 22 gelieferte Signale anspricht. Bei diesen Sensoren kann es sich insbesondere um Thermofühler handeln, welche bei Zen­tralheizungsanlagen die Außentemperatur, die Raumtemperatur und/oder die Vorlauftemperatur des Heizungswassers sowie bei Anlagen zur Warmwasserbereitung die Wassertemperatur in einem Vorratskessel überwachen.Since the amount of air is always adjusted to the correct ratio to the amount of gas supplied via line 13, it is possible to adjust this amount of gas in accordance with the heating power desired in each case. The previously mentioned throttle valve 15 serves this purpose, the position of which is controlled by a gas regulator 21, which responds to signals supplied by sensors 22. These sensors can in particular be thermal sensors which monitor the outside temperature, the room temperature and / or the flow temperature of the heating water in central heating systems and the water temperature in a storage boiler in systems for hot water preparation.

Außer dem Drosselventil 15 kann sich in der Leitung 13 vor dem Strömungssensor 17 noch ein Absperrventil 24 befinden. Das Absperren der Brennstoffleitung 13 hat zur Folge, daß das Ausgangssignal des Strömungssensors 17 das Fehlen eines Gasstromes anzeigt, worauf dann die Regeleinrichtung 11 auch die Förderung von Luft durch den Motor 6 abschalten kann.In addition to the throttle valve 15, a shut-off valve 24 can also be located in the line 13 upstream of the flow sensor 17. Shutting off the fuel line 13 has the result that the output signal of the flow sensor 17 indicates the absence of a gas flow, whereupon the control device 11 can also switch off the delivery of air by the engine 6.

Es ist ersichtlich, daß die Erfindung nicht auf das darge­stellte Ausführungsbeispiel beschränkt ist, sondern Abwei­chungen davon möglich sind, ohne den Rahmen der Erfindung zu verlassen. Insbesondere ist es möglich, zur Angleichung der Brennstofftemperatur an die Lufttemperatur Wärmeaustauscher unterschiedlichster Art zu verwenden. Dabei ist der Wärme­austauscher unter dem Gesichtspunkt auszuwählen, daß im wesentlichen bei allen beim Betrieb der Anlage auftretenden Strömungsgeschwindigkeiten von Luft und Brennstoff ein Temperaturausgelich zwischen diesen beiden Stoffen erfolgt, sich also im Hinblick auf die sehr geringere Brennstoffmenge die Brennstofftemperatur im wesentlichen an die Lufttempera­tur angleicht. Dabei muß der Wärmeaustauscher 16 für den Brennstoff in die der Luftzufuhr dienende Hauptleitung 2 hineinpassen und sollte den Strömungswiderstand für Gas und Luft nicht übermäßig erhöhen, damit einerseits der Gasdruck ausreicht, der Hauptleitung 2 die notwendige Gasmenge zuzu­führen, und andererseits kein Gebläse 7 übermäßiger Leistung Anwendung finden muß, um die benötigte Luftmenge zu för­dern.It can be seen that the invention is not limited to the exemplary embodiment shown, but deviations from it are possible without the scope of the invention leave. In particular, it is possible to use a wide variety of heat exchangers to match the fuel temperature to the air temperature. The heat exchanger is to be selected from the point of view that temperature balancing between these two substances occurs essentially at all flow rates of air and fuel occurring during operation of the system, i.e. the fuel temperature essentially adjusts to the air temperature in view of the very small amount of fuel. The heat exchanger 16 for the fuel must fit into the air supply main line 2 and should not increase the flow resistance for gas and air excessively, so that on the one hand the gas pressure is sufficient to supply the main line 2 with the necessary amount of gas and on the other hand no blower 7 of excessive power application must find to promote the required amount of air.

Claims (2)

1. Einrichtung zur Leistungsregelung von brennstoffbe­feuerten, insbdesondere gasbefeuerten Wärmeerzeugern, mit einem Brenner, einer den Brenner mit einer Luft­eintrittsöffnung verbindenden Hauptleitung, einem in der Hauptleitung angeordneten Strömungssensor, einer in die Hauptleitung im Bereich zwischen dem Strö­mungssensor und dem Brenner mündenden Brennstofflei­tung, über die der Hauptleitung eine vorgegebene Brennstoffmenge zugeführt wird, einem mit der Haupt­leitung in Wirkverbindung stehenden, den Luftdurchsatz in der Hauptleitung bestimmenden Gebläse und einer die Förderleistung des Gebläses in Abhängigkeit von dem Ausgangssignal des Strömungssensors und gegebenenfalls weiteren, das optimale Brennstoff/Luft-Verhältnis beeinflussenden Größen steuernden Regeleinrichtung, dadurch gekennzeichnet,
daß in der Hauptleitung (2) vor dem Strömungssen­sor(10) ein Wärmeaustauscher (16) angeordnet ist, der in die Brennstoffleitung (13) eingeschaltet ist, daß in der Brennstoffleitung (13) ein Drosselventil (15) zum Einstellen des Brennstoff-Druchsatzes und hinter diesem Drosselventil (15) und dem Wärmeaustauscher (16) ein Strömungssensor (17) angeordnet sind und daß die Regeleinrichtung (11) dazu ausgebildet ist, den Luftdurchsatz auf ein konstantes Verhältnis der Strö­mungsgeschwindigkeiten von Brennstoff und Luft einzu­stellen.1.Device for controlling the power of fuel-fired, in particular gas-fired, heat generators, with a burner, a main line connecting the burner with an air inlet opening, a flow sensor arranged in the main line, a fuel line opening into the main line in the region between the flow sensor and the burner, via which the A predetermined amount of fuel is fed to the main line, a blower that is operatively connected to the main line and determines the air throughput in the main line, and a control device that controls the delivery capacity of the blower as a function of the output signal of the flow sensor and, if appropriate, other variables influencing the optimal fuel / air ratio , characterized,
that in the main line (2) in front of the flow sensor (10) a heat exchanger (16) is arranged, which is switched on in the fuel line (13), that in the fuel line (13) a throttle valve (15) for setting the fuel flow rate and A flow sensor (17) is arranged behind this throttle valve (15) and the heat exchanger (16) and that the control device (11) is designed to adjust the air throughput to a constant ratio of the flow velocities of fuel and air. 2. Einrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das Drosselventil (15) in der Brennstoffleitung (13) vor dem Wärmeaustauscher (16) angeordnet ist.2. Device according to claim 1, characterized in that the throttle valve (15) in the fuel line (13) is arranged in front of the heat exchanger (16).
EP88102494A 1987-03-12 1988-02-20 Power regulation device for fuel-fired heat producers Withdrawn EP0281823A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3707883 1987-03-12
DE3707883A DE3707883C1 (en) 1987-03-12 1987-03-12 Device for regulating the output of fuel-fired heat generators

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EP0281823A2 true EP0281823A2 (en) 1988-09-14
EP0281823A3 EP0281823A3 (en) 1988-12-07

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WO2013117516A1 (en) 2012-02-09 2013-08-15 Sit La Precisa S.P.A. Con Socio Unico A method for controlling a burner of a boiler and a control system operating according to this method

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DE3818265A1 (en) * 1988-05-28 1989-11-30 Wolfgang Weinmann Controller for a heating system
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JP6458487B2 (en) * 2014-12-22 2019-01-30 三菱ケミカル株式会社 Combustion gas and oxygen-containing gas mixing method

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WO2000070267A1 (en) * 1999-05-14 2000-11-23 Honeywell B.V. Regulating device for gas burners
WO2013117516A1 (en) 2012-02-09 2013-08-15 Sit La Precisa S.P.A. Con Socio Unico A method for controlling a burner of a boiler and a control system operating according to this method

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EP0281823A3 (en) 1988-12-07

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