EP0326880B1 - Automatic device for modulating the flow of combustion air and gas in gas heating apparatus - Google Patents

Automatic device for modulating the flow of combustion air and gas in gas heating apparatus Download PDF

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Publication number
EP0326880B1
EP0326880B1 EP89101018A EP89101018A EP0326880B1 EP 0326880 B1 EP0326880 B1 EP 0326880B1 EP 89101018 A EP89101018 A EP 89101018A EP 89101018 A EP89101018 A EP 89101018A EP 0326880 B1 EP0326880 B1 EP 0326880B1
Authority
EP
European Patent Office
Prior art keywords
gas
suction fan
combustion air
heating apparatus
pneumatic circuit
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.)
Expired - Lifetime
Application number
EP89101018A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0326880A3 (en
EP0326880A2 (en
Inventor
Giorgio Pastorino
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.)
ING A BERETTA SpA
Original Assignee
ING A BERETTA SpA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ING A BERETTA SpA filed Critical ING A BERETTA SpA
Priority to AT89101018T priority Critical patent/ATE88261T1/de
Publication of EP0326880A2 publication Critical patent/EP0326880A2/en
Publication of EP0326880A3 publication Critical patent/EP0326880A3/en
Application granted granted Critical
Publication of EP0326880B1 publication Critical patent/EP0326880B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F23N1/027—Regulating fuel supply conjointly with air supply using mechanical means
    • 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

Definitions

  • This invention generally relates to gas heating apparatus and more particularly an automatic device for modulating the flow of combustion air and gas in said apparatus so as to optimize the efficiency thereof in any operating conditions.
  • gas heating apparatus are preferably, but not exclusively, intended the gas boilers, in the course of the following description reference will be made to the latter for convenience
  • gas boilers are known and employed in the most cases for heating the water which supplies both a heating apparatus with thermal radiators and the various sanitary fittings of which the houses served by these boilers are provided with.
  • These gas boilers can operate with natural or mechanical draught. In the latter case, they are provided with a suction fan adapted to convey the burnt gas in a stack.
  • this suction fan In the case of gas boilers provided with a suction fan for exhausting the burnt gas, this suction fan is usually of the type having a fixed revolving speed and this feature does not allow the boiler to be used at the maximum of efficiency in any operating conditions, because the draught generated by this suction fan rotating at a fixed speed is constant and therefore does not change with the change of the thermal demand of the user.
  • DE-A-3 401 665 describes an automatic device for modulating the flow of combustion air and gas in a gas heating apparatus provided with a suction fan for the burnt gas and comprising a control means for controlling the number of revolutions of the suction fan depending on the desired water temperature, a pneumatic circuit, an orifice arranged in said pneumatic circuit and a transducer for metering the combustible gas arranged in this pneumatic circuit and controlling the combustible gas metering valve.
  • the throttling member is a bore formed in a thin wall arranged in the flue outlet and this can cause possible vortex and dirt formation which can negatively affect the regulating operation.
  • the pneumatic circuit therein provided does not give an elastic response of the transducer.
  • the automatic device for modulating the flow rate of combustion air and gas in a gas heating apparatus having an air inlet and a flue outlet and provided with a suction fan for the flue and comprising a control means for controlling the number of the revolutions of the suction fan depending on the desired water temperature, a pneumatic circuit, a throttling member arranged in said pneumatic circuit and a transducer for metering the combustible gas, arranged in this pneumatic circuit and controlling a combustible gas metering valve
  • said throttling member is a venturi
  • said venturi is arranged in the combustion air inlet
  • the pneumatic circuit is extending from the venturi throat to the bottom of the combustion chamber through the transducer.
  • a probe is provided for measuring the preset temperature of the water in the boiler and supplying a control signal to the means for controlling the number of revolutions of the suction fan in order to change the revolving speed of the latter with the change of the water temperature.
  • a gas heating apparatus in this case a gas boiler, comprising a firebox 1, in the lower portion of which the burner 2 is arranged, which is fed with combustible gas through the metering valve 3.
  • a heat exchanger 4 is provided which is intended to exchange the heat between the burnt gas and the heat carrier fluid.
  • the top wall of the firebox 1 has an outlet 9 in which a centrifugal suction fan 5 is arranged, which sucks the exhausted gas in the firebox 1 following the path indicated by the arrows 11 and conveys them to the outlet 12.
  • the centrifugal suction fan 5 is provided with an electronic control device 6, for example a TRIAC, the function of which is to control the revolving speed of the motor actuating the centrifugal suction fan 5.
  • a conventional potentiometer for controlling the thermal power and usually employed in the boilers generating warm water of this type has the function to preset the revolving speed of the suction fan 5 and therefore the feeding pressure of the combustible gas to the nozzles of the burner 2 depending on the heating apparatus demand, so as to provide the heating capacity required by the boiler.
  • the number of revolutions of the suction fan 5, when the boiler is heating the sanitary water, is independent from this position.
  • a pneumatic circuit is derived, which is formed of the conduct 8 connected to the firebox 1.
  • a metering transducer 14 is inserted upstream the inlet in the firebox 1, which acts directly on the metering valve 3 of the combustible gas by opening or closing it depending on the pressure differential acting on both sides of the metering transducer 14.
  • the metering transducer has a diaphragm 16 separating the housing 15 of transducer 14 in a pair of variable volume chambers 17,18, but it could be also a pneumatic transducer of different type, for example a piston transducer or a transducer of any other type.
  • the chamber 18 is subjected to the pressure p1 in the firebox 1 and the chamber 17 is subjected to the pressure p2 generated in the venturi 7 and prevailing in the conduct 8.
  • the gas valve 3 is closed and viceversa
  • the pressure p2 in the conduct 8 is higher than the pressure p1 in the firebox, the gas valve 3 is opened.
  • an electronic control center unit which usually comprises a temperature selector for the sanitary water and a temperature selector for the heating water which are of a conventional type and therefore not shown in more detail. Also a flame control center unit is provided, which is also of conventional type and therefore not shown in more detail.
  • a probe is provided, the function of which is to detect the water temperature on the delivery side of the heating apparatus and to supply its signal to the regulator 6 of the number of revolutions of the suction fan 5 through the electronic control center unit.
  • the operation of the gas boiler provided with the centrifugal suction fan for sucking the burnt gas and the automatic modulator device according to the invention is as follows.
  • the suction fan 5 causes a suction in the firebox 1 and therefore a vacuum, while at the same time ejecting through the outlet conduct 12 the burnt gas passing through the heat exhanger 4 which heats the water to be conveyed to the thermal radiators of the heating apparatus.
  • the suction caused by the suction fan 5 in the firebox sucks the combustion air from the outside through the air inlet 10 and conveys it through the venturi 7.
  • the sucked air in the venturi generates a vacuum which, through the conduct 8, acts on the metering transducer 14, the diaphragm 16 of which, depending on the pressure differential between the chambers 17 and 18 of transducer 14, controls the opening degree of the gas valve 3. Therefore, the higher the speed of the suction fan 5 the higher the combustible gas demand and viceversa , in the case of low rotation condition of the fan.
  • the probe in the warm water circuit is intended to measure the water temperature in the boiler and to convey the information about this temperature to the control center unit. As the water is heating, the probe supplies its signal, as already said, to the control center unit which supplies a control signal to the regulator 6 of the revolving speed of suction fan, which reduces its revolving speed so as to conform it to the changed temperature conditions. This procedure is repeated until the water temperature reaches the preset value, i.e. the suction fan decreases its revolving speed with the increase of the water temperature.
  • the sanitary and heating water temperature can be selected and controlled independently from each other.
  • there is only a probe which compares the water temperature of the primary circuit or heating circuit with the preset temperature of the water of the sanitary fittings or with the preset temperature for the heating apparatus, depending on the required user.
  • the modulation carried out by the device according to the invention controls the suction fan so as to cause a change of the number of revolutions thereof and therefore a change of the combustible gas flow rate to the burner 2 in order to allow the water temperature to be maintained to the value preset by the users and therefore, when the temperature decreases, the number of revolutions of fan increases and when the temperature increases, the number of revolutions of fan decreases.

Landscapes

  • 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)
  • Direct Air Heating By Heater Or Combustion Gas (AREA)
  • Sampling And Sample Adjustment (AREA)
EP89101018A 1988-02-01 1989-01-20 Automatic device for modulating the flow of combustion air and gas in gas heating apparatus Expired - Lifetime EP0326880B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89101018T ATE88261T1 (de) 1988-02-01 1989-01-20 Automatische regeleinrichtung des verbrennungsluft- und gasdurchflusses fuer ein gasheizgeraet.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1926788 1988-02-01
IT19267/88A IT1217331B (it) 1988-02-01 1988-02-01 Dispositivo modulatore automatico dell'aria comburente e del gas di combustione per apparecchi di riscalmento a gas

Publications (3)

Publication Number Publication Date
EP0326880A2 EP0326880A2 (en) 1989-08-09
EP0326880A3 EP0326880A3 (en) 1990-11-07
EP0326880B1 true EP0326880B1 (en) 1993-04-14

Family

ID=11156260

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89101018A Expired - Lifetime EP0326880B1 (en) 1988-02-01 1989-01-20 Automatic device for modulating the flow of combustion air and gas in gas heating apparatus

Country Status (5)

Country Link
EP (1) EP0326880B1 (it)
AT (1) ATE88261T1 (it)
DE (1) DE68905932T2 (it)
ES (1) ES2039710T3 (it)
IT (1) IT1217331B (it)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5520533A (en) * 1993-09-16 1996-05-28 Honeywell Inc. Apparatus for modulating the flow of air and fuel to a gas burner

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1297238B1 (it) * 1996-04-10 1999-08-09 Zeltron Spa Unita' riscaldante a gas combustibile per apparecchi domestici e simili
DE10026001B4 (de) * 2000-05-25 2006-08-31 Robert Bosch Gmbh Vorrichtung zum Überwachen eines Gebläses in einem Gasheizgerät
NL1018605C2 (nl) * 2001-07-20 2003-01-21 Nederlandse Gasunie Nv Werkwijze voor het bepalen van het gasverbruik van een gastoestel.

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0108349A3 (de) * 1982-10-30 1985-05-02 Joh. Vaillant GmbH u. Co. Gasbeheizte Wärmequelle
IT1161874B (it) * 1983-02-04 1987-03-18 S I T La Precisa Spa Dispositivo di regolazione per mantenere costante il rapporto aria/gas in un apparecchio di riscaldamento a gas
JPS62190322A (ja) * 1986-02-18 1987-08-20 Rinnai Corp 燃焼制御装置
DE3689309T2 (de) * 1986-07-01 1994-04-28 British Gas Corp Steuerung der Fluidtemperatur bei einer Warmwasserzentralheizungsanlage und für eine Zentralheizungsanlage geeignete Komponenten.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5520533A (en) * 1993-09-16 1996-05-28 Honeywell Inc. Apparatus for modulating the flow of air and fuel to a gas burner

Also Published As

Publication number Publication date
DE68905932T2 (de) 1993-07-22
ES2039710T3 (es) 1993-10-01
IT8819267A0 (it) 1988-02-01
ATE88261T1 (de) 1993-04-15
IT1217331B (it) 1990-03-22
DE68905932D1 (de) 1993-05-19
EP0326880A3 (en) 1990-11-07
EP0326880A2 (en) 1989-08-09

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