GB2270748A - Burner control systems - Google Patents

Burner control systems Download PDF

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Publication number
GB2270748A
GB2270748A GB9219660A GB9219660A GB2270748A GB 2270748 A GB2270748 A GB 2270748A GB 9219660 A GB9219660 A GB 9219660A GB 9219660 A GB9219660 A GB 9219660A GB 2270748 A GB2270748 A GB 2270748A
Authority
GB
United Kingdom
Prior art keywords
burner
air
gas
temperature
control system
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.)
Granted
Application number
GB9219660A
Other versions
GB2270748B (en
GB9219660D0 (en
Inventor
Roy Bratley
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.)
CARADON HEATING Ltd
Original Assignee
CARADON HEATING Ltd
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 CARADON HEATING Ltd filed Critical CARADON HEATING Ltd
Priority to GB9219660A priority Critical patent/GB2270748B/en
Publication of GB9219660D0 publication Critical patent/GB9219660D0/en
Publication of GB2270748A publication Critical patent/GB2270748A/en
Application granted granted Critical
Publication of GB2270748B publication Critical patent/GB2270748B/en
Anticipated expiration legal-status Critical
Expired - Fee Related 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
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/10—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2225/00—Measuring
    • F23N2225/08—Measuring temperature
    • F23N2225/14—Ambient temperature around burners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2225/00—Measuring
    • F23N2225/08—Measuring temperature
    • F23N2225/16—Measuring temperature burner temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2233/00—Ventilators
    • F23N2233/06—Ventilators at the air intake
    • F23N2233/08—Ventilators at the air intake 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

Landscapes

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

Abstract

A gas burner (1) is provided with a thermocouple (4) for sensing the temperature of the surface of the burner; and the signal from the thermocouple (4) is used to control the air/gas flow by adjusting a variable speed fan (2), to the burner, and/or a valve controlling the gas flow rates in order to maintain a substantially constant temperature. The burner may have a metallic skin or be a ceramic burner. <IMAGE>

Description

BURNER CONTROL SYSTEM This invention is concerned with a control method and system for controlling the operation of a gas burner, especially but not necessarily exclusively a gas burner in a domestic boiler.
It is known that so-called fully premix burners, in which all the combustion air is delivered to the burner with the gas, can be advantageous from the point of view of obtaining low NOx emissions. A drawback of fully premix burners is that they are very sensitive to changes in the gas/air mixture, which in turn can lead to problems of ignition, combustion and/or overheating. In order to ensure a stable air/gas ratio, the rate of air flow to the burner must be closely controlled and it becomes difficult to make allowance for variations which are inevitably experienced, such as air inlet duct length, flue length, fluctuations in air inlet temperature and differences in flue gas temperature between ignition and continuous burner operation, all of which influence the air flow resistance.In order to accommodate the extremes of air flow resistance, if the fan which delivers air to the burner was to operate at constant speed, it would have to have a very steep pressure/flow characteristic, which is not considered a practical solution for domestic appliances. As an alternative the fan speed can be controlled to vary the air flow as required to provide the air/gas mixture required, and it has been suggested to use signals obtained from various gas sensors in order to regulate the fan speed, such as air flow sensors, flue CO2 sensors, flue oxygen sensors, pressure sensors or flue temperature sensors. While such control systems will function satisfactorily they tend to be complex and to suffer from calibration drifts.
The present invention seeks to provide an alternative control system which meets the dual requirements of simplicity and reliability. According to the invention there is provided a control system for a gas burner having a fan for delivering air to the burner, comprising temperature sensing means for sensing the temperature of the burner surface, and means responsive to the sensing means for adjusting the air/gas flow to the burner in accordance with the temperature sensed.
The surface temperature of a premix burner is dependent on the flow of air/gas mixture to the burner, and to the air/gas ratio. Thus, at a high flow rate the flame is lifted away from the burner, and its surface will be cooler. Correspondingly, at low mixture flow rates the burner surface will be hotter. Similarly, a mixture containing less air has a higher flame speed, so the flame is closer to the burner surface. Consequently, for a given gas rate, a reduction in air flow procedures a higher temperature at the burner surface. By detecting changes at the burner surface it is possible to adjust the air/gas mixture, by controlling the supply of air and/or gas, to compensate for the changes in conditions which caused the temperature change and hence maintain optimum operating conditions.
Conveniently, the means responsive to the signal from the burner surface temperature sensing means is arranged to control the speed of the fan for adjusting gas ratio. Alternatively, or additionally, the means responsive to the signal could operate a valve to vary the gas delivery in order to change the air/gas ratio. If the fan speed is to be adjusted, the fan is preferably driven by a DC motor and controlled by a voltage signal.
The invention also resides in a method of controlling a premix burner, comprising sensing the temperature of the burner at the surface thereof, and adjusting the air/gas mixture delivered to the burner to maintain a substantially constant temperature at the burner surface.
Some embodiments of the invention are described in more detail below with reference to the accompanying drawings, in which: Figure 1 illustrates in perspective a burner equipped with a control system according to the invention; Figure 2 is a graph of burner surface temperature plotted against air/gas ratio; Figure 3 is similar to Figure 1, but shows a ceramic burner.
Illustrated in Figure 1 is a gas burner 1 having a metal skin which is perforated to define the gas jets.
A variable speed fan 2 is mounted to deliver air and gas into the burner, the gas being delivered to the fan through the pipe 3. A temperature sensor in the form of a thermocouple 4 is bonded to the underside of the burner skin for sensing the burner surface temperature. The signal from the thermocouple is amplified and used to control the fan speed, e.g. by adjusting the voltage supplied to a DC motor which drives the fan.
Figure 2 shows the relationship between the air/gas ratio and the burner surface temperature. Under normal burner operation the air/gas ratio is about 13:1 and the surface temperature is around 4500C. If the temperature at the burner surface increases, this is detected by the thermocouple and as a consequence the voltage supplied to the fan motor is increased so that the air/gas ratio will be correspondingly increased to maintain the temperature substantially at 450 C.
Correspondingly, if the temperature falls below 45OOC, the fan speed will be lowered to reduce the air flow and hence the air/gas ratio. Thus, it will be understood the temperature/air delivery characteristic of the control system will have an opposite slope to the illustrated graph to ensure that a stable operating point will be achieved with the appropriate air flow rate for the desired operating temperature. Of course, outside influences such as partial blockage of the flue, change in gas quality or change in gas supply rate will be automatically compensated with the fan speed being adjusted to ensure the burner surface temperature is maintained at the appropriate level.
Although the system has been described with the air delivery rate being adjusted by control of the fan speed, a similar result can be obtained by using the signal from the temperature sensor to modulate opening and closing of a variable gas valve. With such an arrangement the valve would close in response to higher temperatures and open in response to lower temperatures.
The embodiment of Fig. 3 differs to that of Fig. 1 only in that the burner surface is formed by ceramic tiles 6. So that the surface temperature may be detected, the thermocouple is inserted through a hole in a tile to lie at the outer surface, or to protrude slightly therefrom, which is necessary due to the heat insulating properties of the ceramic material.

Claims (10)

1. A control system for a gas burner having a fan for delivering air to the burner, comprising temperature sensing means for sensing the temperature of the burner surface, and means responsive to the sensing means for adjusting the air/gas flow to the burner in accordance with the temperature sensed.
2. A control system as claimed in Claim 1 wherein the means responsive to the sensing means is arranged to control the speed of the fan.
3. A control system as claimed in Claim 2 wherein the fan has a DC motor
4. A control system as claimed in Claim 1, 2 or 3 wherein the means responsive to the sensing means controls a valve operable to vary the gas flow rate to the burner.
5. A control system as claimed in any preceding claim wherein the temperature sensing means comprises a thermocouple.
6. A method of controlling a pre-mix burner comprising sensing the temperature of the burner at the surface thereof and adjusting the air/gas mixture delivered to the burner to maintain a substantially constant temperature at the burner surface.
7. A method as claimed in Claim 6 wherein the air/gas mixture is adjusted by varying the speed of a fan delivering air to the burner.
8. A method as claimed in Claim 6 or 7 wherein the air/gas mixture is adjusted by modulating valve means controlling the flow of gas.
9. A control system for a gas burner substantially as herein described with reference to the accompanying drawings.
10. A method of controlling a pre-mix burner substantially as herein described with reference to the accompanying drawings.
GB9219660A 1992-09-17 1992-09-17 Burner control system Expired - Fee Related GB2270748B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9219660A GB2270748B (en) 1992-09-17 1992-09-17 Burner control system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9219660A GB2270748B (en) 1992-09-17 1992-09-17 Burner control system

Publications (3)

Publication Number Publication Date
GB9219660D0 GB9219660D0 (en) 1992-10-28
GB2270748A true GB2270748A (en) 1994-03-23
GB2270748B GB2270748B (en) 1995-12-06

Family

ID=10722057

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9219660A Expired - Fee Related GB2270748B (en) 1992-09-17 1992-09-17 Burner control system

Country Status (1)

Country Link
GB (1) GB2270748B (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2286038A (en) * 1994-01-08 1995-08-02 Carver & Co Burner control apparatus
EP1039220A1 (en) * 1999-03-19 2000-09-27 Worgas Bruciatori S.R.L. Method and means for a security control of burners
DE102004055716A1 (en) * 2004-06-23 2006-01-12 Ebm-Papst Landshut Gmbh Firing equipment for gas burners has means for determining value dependent on measured temperature and means for regulating generated temperature using characteristic line representing value range corresponding to ideal temperature
EP1811230A2 (en) * 2006-01-19 2007-07-25 Vaillant GmbH Method for controlling the air-fuel ratio of a fuel operated burner
WO2007093312A1 (en) * 2006-02-14 2007-08-23 Ebm-Papst Landshut Gmbh Method for starting a firing device in unknown general conditions
ITMI20081886A1 (en) * 2008-10-24 2010-04-25 Worgas Bruciatori Srl SPECIAL THERMOCOUPLE FOR BURNERS
WO2012152571A1 (en) 2011-05-06 2012-11-15 Bekaert Combustion Technology B.V. Premix gas burner with temperature measurement
ITBO20120568A1 (en) * 2012-10-17 2014-04-18 Gas Point S R L ADJUSTMENT AND CONTROL EQUIPMENT FOR COMBUSTION IN A FUEL GAS BURNER
DE102021121093A1 (en) 2021-08-13 2023-02-16 Vaillant Gmbh Method for operating a heater, computer program, storage medium, regulation and control device, heater and use of a signal
EP4140708A1 (en) 2021-08-25 2023-03-01 Roland Wolf Device and method for producing a film tube from a film strip in a moulding collar welding method
EP4170234A1 (en) * 2021-10-19 2023-04-26 BDR Thermea Group B.V. Method for controlling a burner

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0158842A1 (en) * 1984-03-30 1985-10-23 Joh. Vaillant GmbH u. Co. Fuel/air ratio regulation device for a fuel-fired heat source

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0158842A1 (en) * 1984-03-30 1985-10-23 Joh. Vaillant GmbH u. Co. Fuel/air ratio regulation device for a fuel-fired heat source

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2286038A (en) * 1994-01-08 1995-08-02 Carver & Co Burner control apparatus
CZ302470B6 (en) * 1999-03-19 2011-06-08 Worgas Bruciatori S. R. L. Safety control of burner and apparatus for making the same
EP1039220A1 (en) * 1999-03-19 2000-09-27 Worgas Bruciatori S.R.L. Method and means for a security control of burners
US6776608B2 (en) * 1999-03-19 2004-08-17 Worgas Bruciatori S.R.L. Method and means for a security control of burners
DE102004055716A1 (en) * 2004-06-23 2006-01-12 Ebm-Papst Landshut Gmbh Firing equipment for gas burners has means for determining value dependent on measured temperature and means for regulating generated temperature using characteristic line representing value range corresponding to ideal temperature
US8636501B2 (en) 2004-06-23 2014-01-28 Landshut GmbH Method for regulating and controlling a firing device and firing device
DE102004055716B4 (en) * 2004-06-23 2007-09-13 Ebm-Papst Landshut Gmbh Method for controlling a firing device and firing device (electronic composite I)
DE102004055716C5 (en) * 2004-06-23 2010-02-11 Ebm-Papst Landshut Gmbh Method for controlling a firing device and firing device (electronic composite I)
US8500441B2 (en) 2004-06-23 2013-08-06 Ebm-Papst Landshut Gmbh Method for regulating and controlling a firing device and a firing device
EP2594848A1 (en) 2004-06-23 2013-05-22 ebm-papst Landshut GmbH Method for controlling a firing device and firing device
EP1811230A3 (en) * 2006-01-19 2012-12-05 Vaillant GmbH Method for controlling the air-fuel ratio of a fuel operated burner
EP1811230A2 (en) * 2006-01-19 2007-07-25 Vaillant GmbH Method for controlling the air-fuel ratio of a fuel operated burner
US8721325B2 (en) 2006-02-14 2014-05-13 Ebm-Papst Landshut Gmbh Method for starting a combustion device under unknown basic conditions
WO2007093312A1 (en) * 2006-02-14 2007-08-23 Ebm-Papst Landshut Gmbh Method for starting a firing device in unknown general conditions
EP2330346A3 (en) * 2008-10-24 2017-09-27 Worgas Bruciatori S.R.L. Temperature sensor for burner, and burner
US8353627B2 (en) 2008-10-24 2013-01-15 Worgas Bruciatori S.R.L. Temperature sensor for burner, and burner
EP2180253A1 (en) * 2008-10-24 2010-04-28 Worgas Bruciatori S.R.L. Temperature sensor for burner, and burner
ITMI20081886A1 (en) * 2008-10-24 2010-04-25 Worgas Bruciatori Srl SPECIAL THERMOCOUPLE FOR BURNERS
CN103502732A (en) * 2011-05-06 2014-01-08 贝卡尔特燃烧技术股份有限公司 Premix gas burner with temperature measurement
WO2012152571A1 (en) 2011-05-06 2012-11-15 Bekaert Combustion Technology B.V. Premix gas burner with temperature measurement
KR101967006B1 (en) 2011-05-06 2019-04-08 베카에르트 컴버스천 테크놀러지 비.브이. Premix gas burner with temperature measurement
KR20140016963A (en) * 2011-05-06 2014-02-10 베카에르트 컴버스천 테크놀러지 비.브이. Premix gas burner with temperature measurement
JP2014519001A (en) * 2011-05-06 2014-08-07 ベーカート・コンバスチョン・テクノロジー・ベスローテン・フェンノートシャップ Premixed gas burner with temperature measurement
CN103502732B (en) * 2011-05-06 2016-05-18 贝卡尔特燃烧技术股份有限公司 There is the premix gas burner of temp measuring system
US9528699B2 (en) 2011-05-06 2016-12-27 Bekaert Combustion Technology B.V. Premix gas burner with temperature measurement
ITBO20120568A1 (en) * 2012-10-17 2014-04-18 Gas Point S R L ADJUSTMENT AND CONTROL EQUIPMENT FOR COMBUSTION IN A FUEL GAS BURNER
US9951951B2 (en) 2012-10-17 2018-04-24 Gas Point S.R.L. Apparatus for controlling and adjusting the combustion in a fuel gas burner
WO2014060991A1 (en) * 2012-10-17 2014-04-24 Gas Point S.R.L. Apparatus for controlling and adjusting the combustion in a fuel gas burner
DE102021121093A1 (en) 2021-08-13 2023-02-16 Vaillant Gmbh Method for operating a heater, computer program, storage medium, regulation and control device, heater and use of a signal
EP4137745A1 (en) 2021-08-13 2023-02-22 Vaillant GmbH Method for operating a heater, computer program, storage medium, regulation and control device, heater and use of a signal
EP4140708A1 (en) 2021-08-25 2023-03-01 Roland Wolf Device and method for producing a film tube from a film strip in a moulding collar welding method
EP4170234A1 (en) * 2021-10-19 2023-04-26 BDR Thermea Group B.V. Method for controlling a burner
WO2023066812A1 (en) * 2021-10-19 2023-04-27 Bdr Thermea Group B.V. Method for controlling a burner

Also Published As

Publication number Publication date
GB2270748B (en) 1995-12-06
GB9219660D0 (en) 1992-10-28

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20020917