EP0120681A1 - Kontrollschaltung für ein Kraftstoffkontrollventil - Google Patents

Kontrollschaltung für ein Kraftstoffkontrollventil Download PDF

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Publication number
EP0120681A1
EP0120681A1 EP84301943A EP84301943A EP0120681A1 EP 0120681 A1 EP0120681 A1 EP 0120681A1 EP 84301943 A EP84301943 A EP 84301943A EP 84301943 A EP84301943 A EP 84301943A EP 0120681 A1 EP0120681 A1 EP 0120681A1
Authority
EP
European Patent Office
Prior art keywords
control circuit
signal
valve
fuel
valve means
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Withdrawn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
EP84301943A
Other languages
English (en)
French (fr)
Inventor
Gordon William Lewis
John Walklate
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.)
PEERLESS STAMPINGS Ltd
Original Assignee
PEERLESS STAMPINGS 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
Priority claimed from GB838307852A external-priority patent/GB8307852D0/en
Priority claimed from GB838325907A external-priority patent/GB8325907D0/en
Application filed by PEERLESS STAMPINGS Ltd filed Critical PEERLESS STAMPINGS Ltd
Publication of EP0120681A1 publication Critical patent/EP0120681A1/de
Withdrawn legal-status Critical Current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
    • F23N5/00—Systems for controlling combustion
    • F23N5/20—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays
    • F23N5/203—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays 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
    • F23N5/10—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples
    • F23N5/102—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermocouples using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2229/00—Flame sensors
    • F23N2229/16—Flame sensors using two or more of the same types of flame sensor
    • 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
    • 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
    • F23N2235/18—Groups of two or more valves

Definitions

  • the present invention relates to a control circuit for use with valve means for controlling the supply of fuel along a pipe to a fuel using appliance such as a domestic or industrial oven, or a space or water heating appliance.
  • the invention is further primarily but not exclusively concerned with flame failure devices, that is devices capable of terminating a supply of fuel to a burner should the combustion of the fuel cease.
  • Fuel control means used in domestic ovens may comprise a first sensing means to sense the temperature of the oven, which sensing means is capable of altering the amount of fuel supplied to a burner so as to maintain the temperature of the oven at a desired level.
  • a thermostatic control Such a device will hereafter be referred to as a thermostatic control.
  • a known type of flame failure device used in conjunction with such a thermostatic control comprises an on/off valve and combustion indicative means. When a flame is absent the valve will shut and the presence of a flame will cause the valve to be held open.
  • the thermostatic control means allows control of temperature and the flame failure device is intended as a safety device to shut off the supply of fuel if for any reason combustion of fuel ceases.
  • Flame failure devices are essential from a safety aspect since if the fuel-using appliance is switched on and combustion ceases, unburnt fuel will continue to be supplied unless the lack of combustion is noticed and the fuel supply terminated. Obviously in the case of some fuels, for example gas, a very dangerous situation could develope and thus it is essential to terminate the supply of fuel as soon as combustion ceases.
  • valves In the case of appliances provided with a thermostatic control valve and a flame failure valve, the valves must be in series with each other.
  • the flame failure valve is provided with by-pass means to the burner since the flame failure valve itself will be shut and hence prevent supply of fuel to the burner.
  • Such devices which may be automatically controlled by clock operated valves opening at a predetermined desired time to enable the fuel to pass through the thermostatic valve and through the by-pass of the flame failure valve which fuel is then ignited by automatic igniting means.
  • the flame failure device operates to open the main flame failure valve and allow full flow of fuel to pass to the burner.
  • control circuit in or for a fuel using appliance of the type in which a valve means is opened to enable combustion of fuel to take place characterised in that said control circuit includes switching means operative to permit of or prevent said valve means being provided with a signal for opening said valve means, and in that said control circuit includes a checking circuit capable of ascertaining that, prior to the sending of said signal, said switch means is in a state to prevent said signal being sent, and, if said switching means is not in a signal sending preventing condition said control circuit prevents the sending of said signal.
  • valve means comprises a flame failure valve.
  • control circuit of the present invention overcomes the problems with devices heretofore proposed in that unless the control circuit is in a "fail-safe" condition then the signal, will not be sent to change the normally closed position of the flame failure valve.
  • the checking circuit is operative to check other parts of the control circuit as to their normal operation and condition and if any abnormality is sensed the checking circuit is operative to prevent the sending of a signal to open the flame failure valve.
  • said switching means comprises a switching circuit incorporated in said control circuit.
  • valve means comprises a flame failure valve
  • the signal opens the valve for a predetermined short period of time.
  • the short period enables ignition to take place, and, on ignition of the fuel the combustion sensing means enables said valve to be maintained in an open state.
  • said short period of time is controlled by the length of time during which the signal from said control circuit is supplied to said valve, said short period of time may cease when combustion is sensed or it may continue for a predetermined short period of time irrespective of the sensing of combustion.
  • said combustion sensing means comprises means for generating or changing an electrical signal which electrical signal is supplied to said control circuit in order to enable generation of a second control signal to said flame failure valve to maintain said valve open during combustion.
  • valve means may comprise two or more valves but preferably said valve means comprises a single valve operable between an open and closed position its operational state being dependent on whether or not:-
  • control circuit of the present invention thereby avoid the necessity of a by-pass and hence ensures that fuel cannot be continually supplied indefinitely without combustion taking place.
  • control circuit of the present invention in particular with fuel using appliances adapted to operate on an automatic mode.
  • automatic control generally comprises three valves, a thermostatic valve, a flame failure valve, and a clock controlled valve.
  • the control circuit of the present invention enables the flame failure valve and the clock valve to be incorporated as a single valve, the clock causing a signal to be sent to the control circuit at a desired time which causes opening of the flame failure valve allowing fuel to pass therethrough and so to be ignited.
  • the control circuit may be provided with a signal from the clock to close said valve.
  • control circuit is provided with means for limiting the time for which said first valve opening signal is present and conveniently said means may comprise a resistor capacitor network the rate of charge to the capacitor being determined by its value and that of an associated resitive component network.
  • control circuit includes further timing means to prevent said first valve opening signal being subsequently regenerated until a predetermined time has elapsed.
  • control circuit includes further means which, in the event of generation of said first valve opening signal and failure of receipt of any combustion indicative signal prevents regeneration of said first valve opening signal until a third signal is received by said control circuit.
  • third signal may comprise disconnecting the control circuit from its power supply.
  • valve means is provided in series with a thermostatically operated valve and conveniently may comprise a valve body incorporating said thermostatically operated valve.
  • thermostatically operated valve is, when set to an in- use position, always at least partially open.
  • thermostatically operated valve may comprise a solenoid valve or other electrically controlled valve operated in accordance with a signal from the control circuit, said signal being varied in accordance with temperature from a temperature sensing device.
  • said temperature sensing device may comprise a thermocouple.
  • a fuel control system operated by the control circuit of the present invention is illustrated, the control system being incorporated in a fluid fuel supply, which fuel will hereinafter be referred to for convenience as gas, to a domestic oven.
  • a gas inlet 10 is connected to a thermostatically controlled valve 11, which includes an on/off valve and which may be set by the manually operable control 12.
  • a temperature sensing device 13 will automatically operate the valve 11 depending on the temperature sensed thereby.
  • the manual contact 12 also operates an on off switch 23 connected by cable 15 to control circuit 31
  • the valve I is connected by a pipe 14 to a flame failure valve 30 which is operated electrically from a signal received from a control circuit 31.
  • the control circuit 31 has connected thereto a combustion sensing device 32 and it is also connected to clock timing unit 33.
  • the output of the flame failure valve 30 is connected by a pipe 34 to the burner 21.
  • control 12 In operation of the device if it is required to work on a non-timed period, i.e. manual operation, the control 12 is turned on to the required temperature, simultaneously turning on the on/off "tap" valve, such operation opening valve I operating switch 23 and, since the switch in clock timing unit 33 will be closed causing operation of ignition unit 22 and switching on control circuit 31.
  • Control circuit 31 is connected via wires 35 to the flame failure valve 30. In the absence of any signal the flame failure valve 30 is maintained closed however, on receipt of a first valve opening signal on line 35 the flame failure valve 30 is opened, by a solenoid for example, and gas can flow through the valve 30 through pipe 34 to the burner 21 the gas being ignited by automatic igniter 22.
  • sensing unit 32 When ignition has taken place combustion is sensed by sensing unit 32 (thermocouple) which sends a signal to the electronic control circuit 31. This has the effect of replacing the first valve opening signal on line 35 with a second, combustion sensing signal, to maintain the flame failure device 30 in an open state.
  • sensing unit 32 thermocouple
  • the first and combustion sensing signals on line 35 are the same but are initiated and maintained by different "instructions" to the control circuit 31.
  • the signal on line 35 will, after a predetermined period of time, for example ten seconds, cease, hence closing the flame failure valve 30 to prevent further gas being.supplied to the burner 21.
  • Safety provisions are built into the circuit 31 to prevent the flame failure valve being operated once again until the power supply to the electronic control circuit 31 has been switched off.
  • Such safety provisions ensure that if for example there is a gas failure the combustion sensing device 32 will sense the lack of combustion, the electronic control circuit 31 will change the signal on line 35 to flame failure valve 30 which will then close. If the gas supply is subsequently restored no gas can pass to the burner 21.
  • a mains supply of voltage is supplied to the primary of transformer Tl and transformed to a low voltage which is subsequently rectified by diodies DR I and DR2.
  • Safety checking circuit CH1 comprises resisters R5 R9, transistors TR3 and TR4 diodes D6 and D7 and relay RL2 having contacts RLC2. The checking circuit will later be described in more detail.
  • Integrated circuit ICI is supplied with a stablised voltage and produces an output signal on an output terminal 40 which causes transistors TR and TR2 to turn on, relay RL I to be energised thus switching contacts RC and causing a voltage to be applied to terminals TSl and TS2 which are connected in circuit with a solenoid for operating the flame failure valve 30.
  • the flame failure valve is thus opened and it permits gas to flow to the burner 21 so as to be ignited by ignitor 22.
  • transistors TR and TR2 are maintained in an "on" state by the signal provided from the combustion sensing device 32 via intergrated circuits IC2 and IC3.
  • relay RLI will be continually energised hence maintaining flame failure valve 30 open.
  • combustion sensing device 32 If combustion ceases the signal from combustion sensing device 32 will cease and the signals from I C2 and I C3 will cease switching off transistors TRI and TR2 and de-energising relay RLI. The flame failure valve 30 will then close.
  • resistor capacitor network R2a,R2b-C2 has enabled C2 to charge providing a signal on line 44 which inhibits operation of IC and prevents an output signal being provided at output 40.
  • IC2 When C5 has discharged, or at least discharged to a predetermined low value once power is provided to transformer TI, IC2 will produce a signal on output 40 for a predetermined length of time dictated by the rate at which C charges cs afore explained.
  • the control circuit therefore permits opening of the flame failure valve 30 for a predetermined short period of time when requested i.e. by switching on the circuit, which switching on is carried out by manual switch 23 and, possibly timed by time control 33 and similarly may be switched off from time control 33, the flame failure valve 30 also being maintained open for an indefinite period providing combustion continues.
  • the gas supply must be terminated.
  • the time control 33 therefore switches off the control circuit thus removing the potential across terminals TSI and TS2 which closes the flame failure valve 30 even though combustion was still taking place.
  • the purpose of the checking circuit CH is to inhibit operation of the control circuit should a fault in the switching circuit which comprises transistors TRI, TR2 by means of which the signal is provided to the flame failure valve 30, be detected.
  • the checking circuit CHI which will hereinafter be described in detail also checks for the correct operation of other important parts of the circuit.
  • a DC voltage from the transformer rectifier circuit incorporating transformer T and diode DR and DR2 is regulated by zener diode ZD and applied to comparator circuit IC2, amplifier circuit IC3 and also to the checking circuit CHI comprising resistors R5, R9, diode D6, D7 transistors TR3, TR4 and relay RL2 having contacts RLC2.
  • the DC voltage stabilized by zener diode ZDI is not however applied directly to relay RLI which is operative to open the flame failure valve 30 nor is the DC voltage applied to the timer circuit incorporated in integrated circuit ICI.
  • Power is supplied via resistor R5 to the collector junction of transistor TR and via resistors R5 and R6 to the junction between resistor R6, diode D1 and diode D3 and hence through diodes D1 and D2 to terminal 42 of integrated circuit lCl, and capacitor Cl and through diodes D3 and D4 to capacitor C2 to test for "short circuits" of the capacitors described in detail later.
  • the comparator circuit IC2 and amplifier circuit IC3 On activation of the control circuit by switching on switch 23 for example, the comparator circuit IC2 and amplifier circuit IC3 is energised but the timer lCl and main relay RLl remains de-energised, thus the solenoid valve operating flame failure valve 30 is de-energised. If a fault exists in the comparator circuit IC2 or amplifier circuit IC3 which results in a power output from IC3 tending to turn-on transistor TRl and/or TR2 the effect will be to reduce the potential at the collector of TRl from its previous high level to a potential substantially the same as earth (provided by the conduction of transistors TR and TR2, ).
  • the control circuit will be inhibited until the thermocouple cools to a predetermined temperature until relay RLI is de-energised and the flame failure valve closed, after which assuming the power supply is reconnected, the timer circuit can re-cycle to open the flame failure valve and initiate ignition of the burner.
  • Some of the components in the circuit such as transistors TRI and TR2, Rla, Rlb are present in duplicate where it will be appreciated only a single component may be used. However, the duplication of such important components ensures that if one component fails the control circuit will continue to operate safely or "fail safe "thus preventing the occurrence of a potentially hazardous condition.
  • thermostatic control valve incorporating a flame failure valve is illustrated the combined valve comprising a gas inlet 10, thermostatic valve 11, manual operating spindle 12 switch 23, thermostatic heat sensing device 13, flame failure valve 30 the flame failure valve operating solenoid 42 is connected by the line 43 to terminals TSI and TS2 shown in Figure 3.
  • the valve body may also include an on/off "tap" valve.
  • control means of the present invention comprises a gas burner 21 connected from valve means 54 by a supply pipe 34, the fuel being supplied to the valve means 54 through pipe 10.
  • the valve means 54 is provided with two solenoid valve 55 and 56, valve 55 comprising a flame failure valve operable from control circuit 50 in accordance with the method of operation as previously described with reference to Figures I and 2, the flame failure valve 55 being capable of being opened on instructions from the control circuit 50 either when the sensing device 32 senses combustion or for a short period of time to allow fuel to pass to the burner 21 and for ignitition of the fuel by the ignitor 22.
  • the second solenoid valve 56 is a thermostatically operated valve and is controlled in accordance with the signal from control circuit 50, which signal is generated or modified in accordance with a temperature sensed by sensing means 53 which may comprise a thermocouple.
  • a manually operable control 12 is connected to the control circuit 50 to provide an input function of the desired temperature and may .be connected to, for example, a variable resistor 51 which is electrically connected to control circuit 50.
  • the control circuit of the present invention enables not only a safer more reliable system but also provides a considerable saving in the valves and pipework and joints necessary to provide the required control of an automatically timed fluid fuel burning device.

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  • 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)
EP84301943A 1983-03-22 1984-03-22 Kontrollschaltung für ein Kraftstoffkontrollventil Withdrawn EP0120681A1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB8307852 1983-03-22
GB838307852A GB8307852D0 (en) 1983-03-22 1983-03-22 Fuel control means
GB838325907A GB8325907D0 (en) 1983-09-28 1983-09-28 Controlling supply of fluid fuel
GB8325907 1983-09-28

Publications (1)

Publication Number Publication Date
EP0120681A1 true EP0120681A1 (de) 1984-10-03

Family

ID=26285583

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84301943A Withdrawn EP0120681A1 (de) 1983-03-22 1984-03-22 Kontrollschaltung für ein Kraftstoffkontrollventil

Country Status (2)

Country Link
EP (1) EP0120681A1 (de)
GB (1) GB2138173A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITTO20090385A1 (it) * 2009-05-20 2010-11-21 Eltek Spa Dispositivo per il controllo dell'alimentazione di gas ad un bruciatore

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2962093A (en) * 1957-01-22 1960-11-29 Baso Inc Control apparatus
US3510236A (en) * 1968-01-29 1970-05-05 Liberty Combustion Corp Ignition control
DE2123458A1 (de) * 1971-05-12 1972-11-23 Industrie A. Zanussi S.P.A., Pordenone (Italien) Selbsttätiges Sicherheitszünd- und Kontrollgerät der Flamme von Gasbrennern
US3705783A (en) * 1971-07-21 1972-12-12 Honeywell Inc Burner safeguard control apparatus
US4073611A (en) * 1976-10-15 1978-02-14 Essex Group, Inc. Control system for gas burning apparatus
US4076487A (en) * 1976-12-27 1978-02-28 Essex Group, Inc. Ignition and control system for gas burning apparatus
FR2434342A1 (fr) * 1978-08-25 1980-03-21 Scholtes Ets Eugen Dispositif de commande pour four de cuisson a gaz
US4226581A (en) * 1978-12-22 1980-10-07 Honeywell Inc. Safe start check circuit

Family Cites Families (11)

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Publication number Priority date Publication date Assignee Title
US3023803A (en) * 1959-01-12 1962-03-06 Honeywell Regulator Co Control apparatus
US3504993A (en) * 1968-03-18 1970-04-07 Electronics Corp America Combustion control circuit
US3524717A (en) * 1968-06-17 1970-08-18 Electronics Corp America Combustion supervision system
US3644748A (en) * 1970-08-03 1972-02-22 Electronics Corp America Combustion supervision apparatus
CH569929A5 (de) * 1974-04-11 1975-11-28 Landis & Gyr Ag
US3958126A (en) * 1974-11-25 1976-05-18 Electronics Corporation Of America Logic circuitry
GB1563296A (en) * 1976-04-13 1980-03-26 United Gas Industries Ltd Electrical controls for heating appliances
US4303383A (en) * 1979-11-09 1981-12-01 Honeywell Inc. Condition control system with safety feedback means
JPS56103708A (en) * 1980-01-24 1981-08-19 Yamatake Honeywell Co Ltd Checking circuit for load driving control element
US4444551A (en) * 1981-08-27 1984-04-24 Emerson Electric Co. Direct ignition gas burner control system
GB2109127B (en) * 1981-11-03 1985-09-04 Thorn Heating Limited Self monitoring control and sensing arrangement

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2962093A (en) * 1957-01-22 1960-11-29 Baso Inc Control apparatus
US3510236A (en) * 1968-01-29 1970-05-05 Liberty Combustion Corp Ignition control
DE2123458A1 (de) * 1971-05-12 1972-11-23 Industrie A. Zanussi S.P.A., Pordenone (Italien) Selbsttätiges Sicherheitszünd- und Kontrollgerät der Flamme von Gasbrennern
US3705783A (en) * 1971-07-21 1972-12-12 Honeywell Inc Burner safeguard control apparatus
US4073611A (en) * 1976-10-15 1978-02-14 Essex Group, Inc. Control system for gas burning apparatus
US4076487A (en) * 1976-12-27 1978-02-28 Essex Group, Inc. Ignition and control system for gas burning apparatus
FR2434342A1 (fr) * 1978-08-25 1980-03-21 Scholtes Ets Eugen Dispositif de commande pour four de cuisson a gaz
US4226581A (en) * 1978-12-22 1980-10-07 Honeywell Inc. Safe start check circuit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITTO20090385A1 (it) * 2009-05-20 2010-11-21 Eltek Spa Dispositivo per il controllo dell'alimentazione di gas ad un bruciatore
WO2010134040A1 (en) * 2009-05-20 2010-11-25 Eltek S.P.A. Device for controlling gas supply to a burner
CN102597627A (zh) * 2009-05-20 2012-07-18 埃尔特克有限公司 用于控制对燃烧器的煤气供应的设备
CN102597627B (zh) * 2009-05-20 2015-07-15 埃尔特克有限公司 用于控制对燃烧器的煤气供应的设备
US9347665B2 (en) 2009-05-20 2016-05-24 Eltek S.P.A. Device for controlling gas supply to a burner

Also Published As

Publication number Publication date
GB2138173A (en) 1984-10-17
GB8407505D0 (en) 1984-05-02

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Inventor name: WALKLATE, JOHN