US3501253A - Automatic ignition systems - Google Patents

Automatic ignition systems Download PDF

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Publication number
US3501253A
US3501253A US699546A US3501253DA US3501253A US 3501253 A US3501253 A US 3501253A US 699546 A US699546 A US 699546A US 3501253D A US3501253D A US 3501253DA US 3501253 A US3501253 A US 3501253A
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US
United States
Prior art keywords
switch
flame
pilot
coil
valve
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
US699546A
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English (en)
Inventor
Kenneth R Wade
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United Gas Industries Ltd
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United Gas Industries Ltd
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Filing date
Publication date
Application filed by United Gas Industries Ltd filed Critical United Gas Industries Ltd
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Publication of US3501253A publication Critical patent/US3501253A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
    • 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

Definitions

  • the present invention relates to automatic ignition systems which may be used, for example, in gas fired boilers, space heaters or water heaters.
  • the main burner of the ap pliance is supplied with gas through a main valve, operation of which is controlled by a flame sensitive device (not uncommonly a switch).
  • This flame sensitive device may take a number of different forms, such as a simple thermostat or a mercury capsule bi-metal or thermo couple and is operated by the heat of-the pilot flame.
  • the pilot flame is burning, the device becomes hot and this allows the main valve for supplying gas to the burner to be opened or opens it directly. If, on the other hand the pilot flame goes out, or is operating at too low a level, the flame sensitive device prevents gas being supplied to the main burner.
  • an ignition apparatus for a gas appliance comprising a solenoid operated main valve for controlling the flow of gas to a main burner, a pilot burner, a solenoid operated pilot valve for controlling the flow of gas to said pilot burner, an electrically operated igniter for lighting the pilot "burner flame, a flame switch adjacent the pilot burner sensitive to the presence of a flame from said pilot burner and actuable between a hot position when a flame is present and a cold position when no flame is present, the pilot valve solenoid coil being connected to an electrical input via the flame switch, when the latter is in the cold position, the main valve solenoid coil being connected to the electrical input via a safety switch and the flame switch, when the latter is in the hot position, means being provided to close the safety switch only when there is an electrical potential across the pilot solenoid coil, the latter being connected to the electrical input via the safety switch when the flame switch is in the hot position, so as to maintain the safety switch closed.
  • the safety switch will open, and both the pilot and main valves will close, the pilot valve being incapable of being re-energised until the flame switch has moved to the col position. If the pilot valve were capable of operating before the flame switch had reached the cold position, and if there were an instantaneous breaking and remaking of the power supply circuit, the solenoid valve would open, and gas would be injected into the combustion space, for a short time until the flame switch had reached the cold position. If thiswere to happen, there would be a tendency for explosive conditions to arise in the combustion space, as soon as the igniter coil were energised by the closing of the flame switch.
  • the safety switch may be in the form of a magnetic reed switch positioned within the magnetic field of the coil of the solenoid of the pilot valve or alternatively may be a simple relay or electronic switch in series or parallel with the pilot valve solenoid or may be an contact operated by the movement of the solenoid valve armature.
  • a neon is placed to bridge the main valve solenoid, to give an indication of operation of this solenoid.
  • a thermostat or time switch may also be placed directly in series with the main valve.
  • a second neon may be connected in parallel with the igniter coil to give indication of failure of the coil, since these coils have limited life.
  • the pilot valve is preferably placed between the gas supply and the main valve, the branch leading "to the pilot burner itself being positioned between the pilot and main valves. Thus, gas cannot be supplied to the main valve and burner, unless the pilot valve is itself open.
  • FIGURE 1 is a circuit diagram of one embodiment of control system according to the invention.
  • FIGURE 2 is a schematic view of the gas supply arrangement for use with the circuit of FIGURE 1;
  • FIGURE 3 is a schematic cross-section through one embodiment of pilot valve according to the invention illustrating the safety switch operated by the pilot valve solenoid coil armature;
  • FIGURE 4 is a fragmentary view of a safety switch in the form of a reed switch in the field of the pilot valve solenoid coil;
  • FIGURE 5 is a portion of the circuit diagram of FIG- URE 1, illustrating the safety switch constructed as an electronic switch;
  • FIGURE 6 is a view similar to FIGURE 5 illustrating the safety switch in the form of a simple relay.
  • the system includes a transformer 10 having a primary Winding 11 and two secondary windings 12 and 13.
  • the first secondary winding 12 is connected to a bridge rectifier 14, to one side X of the output of which is connected a solenoid coil 15, controlling opening of a solenoid operated valve 16 illustrated in FIGURE 2.
  • the second secondary Winding 13 of the transformer 10 is connected to the other side Y of the rectifier and also to an igniter coil 17. Between the igniter coil 17 and the pilot valve solenoid coil 15, is a flame switch 18 which is movable between a cold" and a hot position. In the cold position, the circuit to the pilot valve solenoid coil 15 is completed via the igniter coil 17 and the second secondary of the transformer 13.
  • a main valve solenoid coil 21 is connected between the hot position terminal of flame switch 18 and the one side X of the output of the rectifier 14. Bridging the main valve solenoid coil 21 is a resistance 22 and a neon 23. In series with the main valve solenoid coil 21 is a thermostat or time switch contact 24.
  • FIGURE 2 there is seen a gas supply line 25 having therein a governor 26 and the solenoid operated pilot valve 16. Downstream of the pilot valve, the line 25 divides to be connected first to the main valve 27, which is controlled by main valve solenoid coil 21, and secondly to the pilot burner 28.
  • a flame sensitive device such as a mercury capsule or thermostat is positioned at 29, i.e. immediately in the path of the flame emanating from pilot burner 28. If a flame is playing on the device 29, the fiame switch 18 of FIGURE 1 will move to the hot position.
  • the main burner 30 Connected to the main valve 27 is the main burner 30 which is positioned to be ignited by the pilot flame from burner 28.
  • the switch 24 is closed. If desired, the switch may be omitted and the thermostat and/or time switch arranged in the AC. mains supply to the system.
  • the transformer When the mains supply is connected, the transformer is energised and a DC potential will appear across the output terminals X, Y of the rectifier 14.
  • current With the flame switch 18 in the cold position, current will flow via pilot valve solenoid coil 15, the flame switch 18, the igniter coil 17, and the second secondary 13 of the transformer 10, to the terminal Y of the rectifier.
  • This current flowing through the coil 15 will cause safety switch to close, and an AC. current will be induced by the second secondary 13 to flow through line 19, flame switch 18 and the igniter coil 17.
  • the. pilot valve would have been opened by the coil 15 and gas will flow to the pilot burner 28.
  • the AC. current through igniter coil 17 will cause the latter to glow and will ignite the pilot flame.
  • main valve solenoid When the flame switch has been heated to a suflicient temperature, it will snap over to the hot position and current will be allowed to flow through coil 21 and through resistance 22 and neon 23, which will glow to indicate that the main valve solenoid is opearting. With the main valve solenoid energised, main valve 27 opens, and gas flows to main burner 30 to be lit by the pilot flame. Should the thermostat or time switch 24 indicate that the main burner is no longer required, it -will open and main valve 27 will be closed to cut off supply of gas to the main burner 30.
  • FIGURES 3 to 6 Various forms of safety switch arrangements are illustrated in FIGURES 3 to 6.
  • the pilot valve 16 is illustrated as comprising an inlet union 40 and an outlet union 41, a poppet valve 42 engaging in the inlet union to close the valve.
  • the poppet valve 42 has, as its stem 43, the armature of the solenoid coil 15 of the pilot valve.
  • An extension 43A of the armature 43 is formed of insulating material and carries the movable leaf 48 of the switch 20.
  • the magnetic field created by the coil 15 causes the contacts 22 and 53 carried by the arms 49 and 50 respectively of the' reed switch to close.
  • This reed switch constitutes the safety switch 20 illustrated in FIGURE 1.
  • the safety switch 20 is in the form of an electronic switch, e.g. a thyristor 54, the trigger contact of which is connected across the pilot valve solenoid coil 15.
  • a thyristor 54 the trigger contact of which is connected across the pilot valve solenoid coil 15.
  • the thyristor becomes conductive i.e. in effect it closes the switch 20.
  • FIGURE 6 is illustrated an arrangement in which a simple relay 55 is connected in a series with the coil 15, current flowing through the relay 55 closing the switch 20.
  • a voltage sensitive relay 55A is connected in parallel with the pilot so enoid coil 15.
  • An ignition apparatus for a gas appliance comprising, in combination:
  • a flame switch adjacent said pilot burner sensitive to the presence of a flame from said pilot burner, effective to be actuated between a cold position when no pilot flame is present and a hot position when a pilot flame is present;
  • a safety switch comprising a single relay switch in series with said second solenoid coil
  • (k) means connecting said second solenoid coil to 5 6 said electrical input means via said flame switch, References Cited When thfi latter iS in the Cold position; (1) means connecting said first solenoid coil to said electrical input means via said safety switch and 2100308 5/1940 Beggs said flame switch, when the latter is in the hot 110- 5 2,261,092 10/1941 petefson 431' 46 Sition; 2,269,157 1/1942 Levine 431-46 (m) means closing said safety switch only when there 2,730,169 1/1956 DeubFl 43145 is an electrical potential across said second sole- 2,800,176 7/ 1957 introduced 431-45 noid; and
  • (11) means connecting said second solenoid coil to 1 said electrical input means via said safety switch, when said flame switch is in said hot position, eflfcc-' tive to return said safety switch closed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Combustion (AREA)
  • Feeding And Controlling Fuel (AREA)
US699546A 1967-02-09 1968-01-22 Automatic ignition systems Expired - Lifetime US3501253A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6313/67A GB1171831A (en) 1967-02-09 1967-02-09 Automatic Ignition Systems for Burners.

Publications (1)

Publication Number Publication Date
US3501253A true US3501253A (en) 1970-03-17

Family

ID=9812226

Family Applications (1)

Application Number Title Priority Date Filing Date
US699546A Expired - Lifetime US3501253A (en) 1967-02-09 1968-01-22 Automatic ignition systems

Country Status (6)

Country Link
US (1) US3501253A (xx)
BE (1) BE710540A (xx)
DE (1) DE1601324A1 (xx)
FR (1) FR1568107A (xx)
GB (1) GB1171831A (xx)
NL (1) NL6801754A (xx)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3589846A (en) * 1970-03-23 1971-06-29 Therm O Disc Inc Burner control system
US3620659A (en) * 1968-07-09 1971-11-16 Robertshaw Controls Co Fuel control system and parts therefor or the like
US3938936A (en) * 1974-09-05 1976-02-17 Carrier Corporation Fluid control system
US4070143A (en) * 1976-06-21 1978-01-24 Johnson Controls, Inc. Fuel ignition system including an igniter providing a lingering spark
US4077762A (en) * 1976-06-21 1978-03-07 Johnson Controls, Inc. Fuel ignition system having contact interlock protection
US4106889A (en) * 1976-11-19 1978-08-15 Robertshaw Controls Company Burner ignition system
US4255118A (en) * 1978-04-20 1981-03-10 Robertshaw Controls Company Electric ignition system
US4323342A (en) * 1980-01-09 1982-04-06 General Electric Company Burner ignition and control system
US20090181334A1 (en) * 2008-01-10 2009-07-16 Derek Moore Burner ignition control system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2200908A (en) * 1939-08-30 1940-05-14 Surface Combustion Corp Fuel burner control system
US2261092A (en) * 1938-02-25 1941-10-28 Honeywell Regulator Co Burner control system
US2269157A (en) * 1940-07-31 1942-01-06 Gen Electric Automatic fluid fuel burner control
US2730169A (en) * 1950-11-06 1956-01-10 Gen Controls Co Gas burner control system
US2800176A (en) * 1954-09-27 1957-07-23 Whirlpool Seeger Corp Automatic gas ignition and burner control system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2261092A (en) * 1938-02-25 1941-10-28 Honeywell Regulator Co Burner control system
US2200908A (en) * 1939-08-30 1940-05-14 Surface Combustion Corp Fuel burner control system
US2269157A (en) * 1940-07-31 1942-01-06 Gen Electric Automatic fluid fuel burner control
US2730169A (en) * 1950-11-06 1956-01-10 Gen Controls Co Gas burner control system
US2800176A (en) * 1954-09-27 1957-07-23 Whirlpool Seeger Corp Automatic gas ignition and burner control system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3620659A (en) * 1968-07-09 1971-11-16 Robertshaw Controls Co Fuel control system and parts therefor or the like
US3589846A (en) * 1970-03-23 1971-06-29 Therm O Disc Inc Burner control system
US3938936A (en) * 1974-09-05 1976-02-17 Carrier Corporation Fluid control system
US4070143A (en) * 1976-06-21 1978-01-24 Johnson Controls, Inc. Fuel ignition system including an igniter providing a lingering spark
US4077762A (en) * 1976-06-21 1978-03-07 Johnson Controls, Inc. Fuel ignition system having contact interlock protection
US4106889A (en) * 1976-11-19 1978-08-15 Robertshaw Controls Company Burner ignition system
US4255118A (en) * 1978-04-20 1981-03-10 Robertshaw Controls Company Electric ignition system
US4323342A (en) * 1980-01-09 1982-04-06 General Electric Company Burner ignition and control system
US20090181334A1 (en) * 2008-01-10 2009-07-16 Derek Moore Burner ignition control system

Also Published As

Publication number Publication date
NL6801754A (xx) 1968-08-12
DE1601324A1 (de) 1970-11-05
FR1568107A (xx) 1969-05-23
BE710540A (xx) 1968-06-17
GB1171831A (en) 1969-11-26

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