EP1122498A2 - Appareils à gaz et dispositifs de commande - Google Patents

Appareils à gaz et dispositifs de commande Download PDF

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Publication number
EP1122498A2
EP1122498A2 EP01300583A EP01300583A EP1122498A2 EP 1122498 A2 EP1122498 A2 EP 1122498A2 EP 01300583 A EP01300583 A EP 01300583A EP 01300583 A EP01300583 A EP 01300583A EP 1122498 A2 EP1122498 A2 EP 1122498A2
Authority
EP
European Patent Office
Prior art keywords
blower
gas
thermistor
flow
enclosure
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Withdrawn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
EP01300583A
Other languages
German (de)
English (en)
Other versions
EP1122498A3 (fr
Inventor
Ronald Kenneth Russell
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.)
Smiths Group PLC
Original Assignee
Smiths Group PLC
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 Smiths Group PLC filed Critical Smiths Group PLC
Publication of EP1122498A2 publication Critical patent/EP1122498A2/fr
Publication of EP1122498A3 publication Critical patent/EP1122498A3/fr
Withdrawn legal-status Critical Current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
    • F23N1/06—Regulating fuel supply conjointly with draught
    • F23N1/062—Regulating fuel supply conjointly with draught using electronic means
    • 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
    • F23N5/14—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermo-sensitive resistors
    • F23N5/143—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermo-sensitive resistors using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements
    • F23N5/242—Preventing development of abnormal or undesired conditions, i.e. safety arrangements using electronic means
    • 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
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/08—Microprocessor; Microcomputer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2231/00—Fail safe
    • F23N2231/10—Fail safe for component failures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2231/00—Fail safe
    • F23N2231/26—Fail safe for clogging air inlet
    • 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
    • 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
    • F23N2235/14—Fuel valves electromagnetically operated

Definitions

  • This invention relates to gas appliances of the kind including a gas burner, a blower for causing flow of air and combustion products in the appliance and a detector for detecting inadequate flow through the appliance.
  • Gas appliances such as gas boilers, include various safety features and often have some means for ensuring that gas supply does not continue if air supply to the appliance is inadequate for correct combustion.
  • a pressure sensor detects the pressure at the blower outlet. In this way, any failure of the blower or blockage to flow of air or combustion products can be detected.
  • the problem with this previous arrangement is that the pressure sensors are relatively expensive, especially those needed to detect low air pressures. They can also be unreliable leading to unsatisfactory combustion or unnecessary boiler shut-down.
  • multiple pressure sensors are needed in boilers having an output that can be modulated.
  • a gas appliance of the above-specified kind characterised in that the detector includes a thermal sensor responsive to flow caused by the blower.
  • the thermal sensor preferably includes a temperature-dependent electrical device, such as resistor or thermistor.
  • the appliance includes two temperature-dependent electrical devices, the first of which is exposed to flow caused by the blower and the second of which is protected from such flow such that operation of the blower causes different changes in the first and second devices.
  • the appliance is preferably a boiler having a heat exchanger located in an enclosure between the burner and the inlet of the blower, the thermal sensor being responsive to gas flow along a passage opening into the enclosure.
  • the enclosure is preferably contained within an outer housing, the outlet of the blower opening to an exhaust passage of a balanced flue and an inlet passage of the balanced flue opening into the housing outside the enclosure.
  • a gas boiler including a burner 1 connected to a gas supply pipe 2 via a gas valve 3.
  • a heat exchanger 4 mounted above the burner 1 transfers heat produced by the burner to water or ventilation air.
  • the boiler also includes an induced draught blower 5 having its inlet located above the heat exchanger 4 and its outlet coupled to the central, exhaust passage 6 along a balanced flue 7.
  • the casing 8 of the boiler is sealed and opens into the outer, inlet passage 9 of the flue 7 so that, when the blower 5 operates it extracts combustion products from the boiler to the exhaust passage 6 of the flue and induces a draught of air along the outer, inlet passage of the flue to the burner 1 in order to enable combustion.
  • An inner enclosure 80 extends between the burner 1, heat exchanger 4 and blower 5 to control flow of air and combustion products from the burner to the blower inlet.
  • the boiler is conventional.
  • the boiler also includes a control system 10 having an output on line 11 to the gas valve 3, to control its operation.
  • the control system 10 is shown in greater detail in Figure 2 and comprises a flow-sensing detector unit 20 and a boiler logic unit 30.
  • the flow-sensing unit 20 includes two negative temperature coefficient thermistors 12 and 13, or other temperature-responsive resistors, connected in series across a voltage source 14. A series of two further fixed resistors 15 and 16 is also connected across the voltage source 14, in parallel with the two thermistors 12 and 13.
  • the sensing unit 20 includes a comparator 17 having one input 18 connected to the junction 19 between the two thermistors 12 and 13 and its other input 21 connected to the junction 22 between the two fixed resistors 15 and 16.
  • the output 23 of the comparator 17 is connected to one input of the logic unit 30 and is also connected with the positive terminal of the voltage source 14 via a further resistor 24.
  • the logic unit 30 has several further inputs 25 from other conventional safety sensors, such as a spark sensor 26 and provides the output on line 11 to open the gas valve 3 when all its inputs indicate that it is appropriate to supply gas to the burner 1.
  • the two thermistors 12 and 13 are mounted adjacent to one another in a block 50 of metal or plastics located in an opening of the inner enclosure 80 adjacent the blower 5.
  • One thermistor 12 is located in a channel 51 that opens at opposite ends of the block 50 so that one end is at the blower inlet pressure and the opposite end is at the (higher) ambient pressure within the casing 8, which is the pressure at the air inlet of the burner 1. There is, therefore, a pressure differential along the channel 51 causing air to flow down along the channel, over the thermistor 12.
  • the other thermistor 13 is located in a second channel 52 through the block 50, which is blocked so that it is not exposed to any air flow.
  • the blower 5 does not operate or if there is some restriction to flow through the exhaust 6 or inlet passage 9 of the flue 7, the flow over the exposed thermistor 12 will fall and its temperature will rise closer to that of the concealed thermistor 13.
  • the voltage at the junction 19 between the thermistors will, therefore, rise to approximately half that across the series pair of the two thermistors.
  • the comparator 17 is arranged so that its output causes the logic unit 30 to maintain the gas valve 3 off in such a condition.
  • the present invention provides effective monitoring in a gas appliance of both air flow to a burner and the flow of combustion products from a burner without the need for a pressure sensor. It will be appreciated that the invention is not confined to gas boilers but could be used in other gas appliances. Other thermal means responsive to air flow could be used instead of thermistors.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Combustion (AREA)
  • Regulation And Control Of Combustion (AREA)
EP01300583A 2000-02-02 2001-01-23 Appareils à gaz et dispositifs de commande Withdrawn EP1122498A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0002263 2000-02-02
GBGB0002263.2A GB0002263D0 (en) 2000-02-02 2000-02-02 Gas appliances and control systems

Publications (2)

Publication Number Publication Date
EP1122498A2 true EP1122498A2 (fr) 2001-08-08
EP1122498A3 EP1122498A3 (fr) 2004-01-21

Family

ID=9884730

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01300583A Withdrawn EP1122498A3 (fr) 2000-02-02 2001-01-23 Appareils à gaz et dispositifs de commande

Country Status (2)

Country Link
EP (1) EP1122498A3 (fr)
GB (2) GB0002263D0 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6766771B1 (en) 2003-09-11 2004-07-27 The Water Heater Industry Joint Research And Development Consortium Fuel-fired water heater with dual function combustion cutoff switch in its draft structure

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106524219A (zh) * 2016-12-19 2017-03-22 大连圣鼎工业装备有限公司 一种环保型自动控制低指标排放燃气锅炉机组

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0087539A1 (fr) * 1982-03-03 1983-09-07 E.L.M. Leblanc, Société dite: Perfectionnements apportés aux chaudières à extraction mécanique
JPS6284224A (ja) * 1985-10-09 1987-04-17 Youei Seisakusho:Kk 給湯器
US4951651A (en) * 1989-09-28 1990-08-28 Rheem Manufacturing Company Vent overpressurization detection system for a fuel-fired, induced draft furnace
DE9210862U1 (fr) * 1991-08-16 1992-10-15 Joh. Vaillant Gmbh U. Co, 5630 Remscheid, De

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4629113A (en) * 1984-10-05 1986-12-16 Rhr, Inc. Furnace controller
US4792089A (en) * 1985-11-26 1988-12-20 Carrier Corporation Self-correcting microprocessor control system and method for a furnace
KR900006243B1 (ko) * 1986-10-16 1990-08-27 린나이 가부시기가이샤 연소장치
AT401569B (de) * 1991-12-12 1996-10-25 Vaillant Gmbh Heizeinrichtung
US5865611A (en) * 1996-10-09 1999-02-02 Rheem Manufacturing Company Fuel-fired modulating furnace calibration apparatus and methods

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0087539A1 (fr) * 1982-03-03 1983-09-07 E.L.M. Leblanc, Société dite: Perfectionnements apportés aux chaudières à extraction mécanique
JPS6284224A (ja) * 1985-10-09 1987-04-17 Youei Seisakusho:Kk 給湯器
US4951651A (en) * 1989-09-28 1990-08-28 Rheem Manufacturing Company Vent overpressurization detection system for a fuel-fired, induced draft furnace
DE9210862U1 (fr) * 1991-08-16 1992-10-15 Joh. Vaillant Gmbh U. Co, 5630 Remscheid, De

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 0112, no. 89 (M-625), 18 September 1987 (1987-09-18) -& JP 62 084224 A (YOUEI SEISAKUSHO:KK), 17 April 1987 (1987-04-17) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6766771B1 (en) 2003-09-11 2004-07-27 The Water Heater Industry Joint Research And Development Consortium Fuel-fired water heater with dual function combustion cutoff switch in its draft structure

Also Published As

Publication number Publication date
EP1122498A3 (fr) 2004-01-21
GB2358915A (en) 2001-08-08
GB0002263D0 (en) 2000-03-22
GB0102221D0 (en) 2001-03-14

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