CA1037107A - Spark igniter system for gas appliance pilot ignition - Google Patents
Spark igniter system for gas appliance pilot ignitionInfo
- Publication number
- CA1037107A CA1037107A CA232,031A CA232031A CA1037107A CA 1037107 A CA1037107 A CA 1037107A CA 232031 A CA232031 A CA 232031A CA 1037107 A CA1037107 A CA 1037107A
- Authority
- CA
- Canada
- Prior art keywords
- terminal
- power source
- flame
- solid state
- voltage
- 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
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q3/00—Igniters using electrically-produced sparks
- F23Q3/004—Using semiconductor elements
-
- 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
- F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
- F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2227/00—Ignition or checking
- F23N2227/36—Spark ignition, e.g. by means of a high voltage
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2229/00—Flame sensors
- F23N2229/12—Flame sensors with flame rectification current detecting means
Abstract
SPARK IGNITER SYSTEM FOR GAS APPLIANCE PILOT IGNITION
ABSTRACT OF THE DISCLOSURE
A spark igniter operative from a low voltage DC source for a gas or vaporous fuel pilot including a simplified ringing-choke DC-to-DC converter and a relaxation oscillator/pulser for producing the ignition spark. An inhibit circuit utilizing a flame rod and the flame rectification phenomenon disables the relaxation oscillator/
pulser when the pilot flame is extant.
ABSTRACT OF THE DISCLOSURE
A spark igniter operative from a low voltage DC source for a gas or vaporous fuel pilot including a simplified ringing-choke DC-to-DC converter and a relaxation oscillator/pulser for producing the ignition spark. An inhibit circuit utilizing a flame rod and the flame rectification phenomenon disables the relaxation oscillator/
pulser when the pilot flame is extant.
Description
~ . ~
E. A Carls~n 4 SPARK IGNITER SYSTEM FOR GAS APPLL~NCE PILOT IGNITION
BAC~GROIJND OF THE INVENTION
Field of the Invention The invention relates to ignlters for gas or vaporous fuel heating appliances generally, and more particularly, to spark igniter devices for igniting a gas fueled pilot, whLch in turn, may ignite a main burner.
Descrlptlon of the Prior Art In the prior art, heating appliances, such as furnaces, hot water heaters, cooking devices, etc., operating from gaseous or vaporous fuels, are extremely well known. A variety of fuels are com-monly used by such appliances Includlng natural gas, propane, butane and other slmilar fuels. It has been common practlce for a pilot to be left burning contlnuously at a relatively low gas consumption rate, in order that the appliance can (manually or automatically) be placed into full operation conveniently and without significant delay.
Recently, attention has been focused on measures for the conservation of fuels however, and this has tended to spawn various-new hardware for starting of such gas appliances without the need for a con-tinuous burning pilot.
Among these devices are those which provide for ignition of the appliance main burner by means of an electrlcally heated element, .
or by means of a spark gap. Spark gaps have the advantage of not re-quiring a heat-up time, and they are relatively economical of electrical energy For the sake of reliability however, some recent devices of the type have provlded for electrical ignition, by spark gap for example, of a gas fired pilot, the said gas-fired pilot in tUM operatlng to ignite the main burner or burners of the appliance. The art concerning gas fired pilots is developed to the point where main burner ignition is very - ~
-~ E. A. Carlson 4 ``- 103710'7 reliably effected. Direct spark ignition of a main burner has been undertaken in this art but may introduce some prob-lems such as excessive gas collection before ignition.
At least one prior art device is known which involves the use of spark ignition of a gas fired pilot. Such a device is described in U. S. Patent 3,662,185, entitled "Spark Generator and Components Therefor". That device makes use of the so-called flame rod (known in these arts per se) which mav act as one spark electrode and also as an electrode providing flame rectification or conduction as the pilot flame plays on the flame rod. The fact that such conduction occurs and is unipolar has given rise to the term "flame rectification". The resistance of the flame path is on the order of several megohms, and that resistance is employed as an element in a circuit for disabling the self-recycling spark voltage generator while the pilot is lighted. The indicated prior art device makes use of a voltage trippler as a power source for a relaxation oscillator employing an element such as a neon tube. Such gas discharge devices normally reguire somewhat higher operating voltages than are provided by the low voltage direct current power sources common in recreational vehicles and the like. That reference derives the necessary higher direct current source voltage by a relatively expensive method. The manner in which the present invention builds upon this reference to provide a unique and significantly more efficient and cost effective igniting system- will be evident as this descriptlon proceeds.
.; f , , E. A. Carlson 4 `- 10371~7 Another reference of interest is United States Patent No. 3,877,864 issued April 15, 1975.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a spark pilot igniter for gaseous and vaporous fuel systems including a fuel operated pilot, said igniter including a spark gap adjacent to said pilot, said igniter being opera-tive from a low voltage first direct current power source, comprising: a ringing choke oscillator connected to said first 10 direct current power source for producing a second direct current voltage source higher than said power source; charg-ing means including a first capacitor and a series resistance, said first capacitor being connected to charge from said second direct current voltage source; a first solid state switch device having main current carrying electrodes includ-ing an anode and a cathode and a control electrode capable of controlling the effective resistance between said anode and cathode from a relatively low to a relatively high value; a high ratio step-up transformer having primary and secondary : 20 windings, said primary winding being connected in series with said main current carrying electrodes of said first solid state switch device and said second direct current voltage source, said secondary winding being operatively con-nected to said spark gap; a relaxation osciilator connected to ~5 said second voltage source for producing periodic output -~ E. A. Carlson 4 103710~
voltage pulses, said voltage pulses being connected to said first solid state switching device control electrode to cause said resistance between said anode and cathode to assume said low effective resistance value momentarily, thereby to produce a pulse of current in said transformer primary and a corre-sponding stepped-up voltage applied to said spark gap contem-poraneously with the occurrence of said relaxation oscillator output pulses, thereby to effect ignition of said pilot:
means including a flame rod extending at least partially into the flame of said pilot, said flame rod ~eing connected to provide a flame current path through said flame from a terminal of said transformer secondary; and a return current path for the other terminal of said transformer secondary con-nected to a point in the circuit of said relaxation oscillator such that said flame current reduces the effective supplyvoltage to said relaxation oscillator below the point of opera-bility of said relaxation oscillator, said ringing choke oscillator comprising a first series current path having in order, a forward poled diode, an inductor, first and second resistors, all in series across said first power source, said diode connecting to a first terminal of said first power source and the second of said resistors con-necting to a second terminal of said first power source;
-3a-~,;
.~. ,s/i A
' _ - E. A. Carlson 4 ~037~7 and including means comprising a tap along the winding of said inductor and.a second solid state device.having an emitter-collector current path and a base electrode, said emitter-collector current path being connected from said S inductor tap to said second terminal of said first power source, and said base electrode being connected to the junc-tion of said resistors, thereby to produce oscillatory pulses of relatively high peak voltage at the:junction of said in-. ductor and the first of said resistors with respect to said first power source second terminal.
... ~~ .
BRIEF DESCRIPTION OF THE DRAWING
In the accompanying.drawing which illustrates an ex-emplary embodiment of the present invention:
The single figure is an electrical schematic diagram.
! 15 DESCRIPTION OP THE PREFERRED EMBODIMENT
- -Referring to the drawing, the structure and operation of the device of the invention will be described.
The invention.is particularly useful, efficient, and economical in connection with electrical power sources as represented by the block Eo~ such as are typically used in recreational vehicles. Although the invention is not so limited, a typical embodiment designed for operation from the 12 volt storage battery system of a recreational vehicle will be described.
'` .
:~
~ 3b-.
E. A. Carlson 4 103710~7 On the drawing, the circuitry to the right of Cl (the filter/
sto~age capacitor) requires a direct current voltage on the order of approximately 90 to 100 volts for satisfactory operation. The circuitry to tha left of Cl (and including Cl itself) is devoted to the development of this higher direct current voltage from the 12 volt source .
The aforementioned U.S. Patent 3,662,185, shows and describes the relaxation oscillator/pulser circuit for operating the spark igniter across the gap between the flame rod FR and the pilot light grounded enclosure PL. Basically, this circuLt operates to charge up a capacitor ~ C2, through a large valùe resistor R4, to the firing voltage of neon lamp Ll, which is typically on the order of 60 to 75 volts. The firing of L1 essentially connects C2 across R6, the latter beLng a relatively low value reslstor, through a current limiting resistor R5 and diode D3 which acts as a current "check-valve". Thus, a pulse is provided to the gate electrode of the silicon controlled rectifier CRl, bringing that device into conduction.
That conduction and the resultant current pulse occurs around a loop in-cluding Cl, the primary or pulse transformerTl, and the CRl anode/cathode main current path. The impedance or internal reslstance of the ringing-choke converter, Is such that it could not supply or sustain such a current, con-sequently the said current pulse is sustained substantially only until the charge of capacitor Cl is appreciably decreased. At that time, both the effective voltage across the anode cathode circuit of CRl and the CRl gate electrode triggering pulse from the neon lamp relaxation oscillator will have -both greatly decreased. Extinguishment of Ll through the "dumping" of C2 charge, starts a new cycle of recharing of C2 throughR4. The diode D3 prevents the flow of any back current from the CRl gate electrodeduring transient conditions accompanying the spark discharge between FR and PL.
Transformer Tl, which has a relatively large step-up ratio, is capable of producing a secondary voltage on the order of 16 Kilovolts to produce the 3~ spark discharge.
E. A. Carlson 4 It will be noted that, as is known, the flame rod FR, acts as an anode of a high resistance diode in coope~ation with the flame itsel~ and the grounded housing of the pLlot PL. Since the relaxation oscillator/sparking pulser circuitry (i.e., that to the right of Cl) is to be inhibited, or disabled, once the pilot flame is actually established, use is made of the so-called flame rectification characteristic just described. The forward resistance of this "flame diode" is in the megohm range and, in order to serve the purpose of inhibiting the relaxation oscillator/pulser, must be supplied with current poled at a positive potentlal with respect to ground as applLed to FR.
In the circuit of the drawing, the junction of C2, r 1 and R4 also provides a return for the secondary of the pulse transformer Tl.
Between spark cycles, the "flame diode" (assuming the pllot flame is extant) permlts some current through R4 and the sald secondary of Tl lS to pass through the said flame diode. The value of R4 is chosen so that the flame conduction reslstance and the said R4 act as a dlvider, reducing the potential at the said junction of Ll, C2 and R4 to a value below the mlnimum firing potential of Ll.
From the foregolng information, it will be seen that the source constituted by the DC-to~C converter (ringing-choke ascillator) to the left of Cl, must be positive at the upper end of R4. While there are many ways that this can be accomplished with a DC~DC converter, it is essential that it be accomplished in an efficient, low cost manner.
Since, as already indicated, a grounded negative storage battery source (Eo) of 12 volts, for example, is also an initial constraint, the DC-to-DC must handle this situation without resorting to multi-wlnding trans-formers, or other more expensive expedients.
Before describing the ringlng-choke converter of the present invention in detail, it may be useful to point out that prior art ringing-choke .: , .
-E. A. Carlaon 4 10371~7 converter circuits for general application, are commonl~ more complex.
See, for example, the text entitl~ CA Silicon Power Circuits Manual"
(a publication of Radio Corporation sf America as part of their technical series SP-51, dated 1969). Page 168 describes a typical prior art ringing-choke inverter (or converter) circuit.
The ringing-choke oscillator circuit of the present invention includes only a tapped tank coil or auto transformer T2, a single PNP
transistor, a pair of diodes, a filter/storage capacitor and three resistors.
It will be apparent to those skilled in the electronic circuit arts that a PNP translstor Q1 is appropriate for the polarities indicated and aforementloned. In an initial condition, current from the positive pole of the source Eo passes through diode Dl through T2. Most of thls current follows the tap through the emitter of Ql and passes through the emitter/collector current path of the said Ql to the negative Eo terminal (l.e., ground). The resistors R1 and R2 constitute a base biasing arrangement for Ql, -such that, In the qulescent condition, Q1 is biased Into a conducting condition substantially below saturatlon.
- The growth of current through the upper portion of T2, l e., from Dl to the tap, induces a signal into the lower half of T2 which is regenerative in polarity as It reaches the base of Ql. That is, this regenerative condition Is extant until Q1 beglns to saturate, at which timethe rate of current growth in the upper portiosl of T2 falls off. As is well understood in electromagnetic circuit theory, the induced regenerative signal afore-mentioned in the lower portlon of T2 then quickly reverses and becomes degenerative, hastening the cutoff of Ql until that portion of the cycle runs its course. Subsequently the reconduction of Ql starts the cycle ~; over again. Thus, the junction of R2 and R3 provides an alternating signal which is rectified by D2 through current limiting resistor R3 in order to charge capacitor Cl .
E. A. Carlson 4 ' 103qlO7 Although the flame conduction referred to h~reinbefore is effective to inhibit the further functLon o~ the relaxation oscillator/
pulser by reducing thP voltage at the junction of R4 and C2, the ringing-choke oscillator continues ,to operate and maintain the fully charged c~nditi~3n of filter/storage capacitor Cl. .
Typical circuit values for the em~odiment of the flgure are given in Table I below. A typical operating frequency for the said ringing-choke oscillator is 20KHz.
, ' , ' ' .
TABLE OF TYPrCAL COMPO,IJENT TYPES AND VALUES
Dl, D2 and D3 ' IN4002 Ql MPSD 51 (Motorola) Rl 4.7KQ:
R2 470 n ., R3 150 S~ .
R4 ' 22 Megohms R5 IK n R6 . -lK Q
CRI SCR
~;, ' 2 0 . ' C l . 2 . 2 ,u fd C2 0. 001P fd Certain modificatlons and variations will suggest themselves to those sk}lled in these arts, Accordingly, it is not intended that the ~: scope of the invention should be limited by the drawing or this
E. A Carls~n 4 SPARK IGNITER SYSTEM FOR GAS APPLL~NCE PILOT IGNITION
BAC~GROIJND OF THE INVENTION
Field of the Invention The invention relates to ignlters for gas or vaporous fuel heating appliances generally, and more particularly, to spark igniter devices for igniting a gas fueled pilot, whLch in turn, may ignite a main burner.
Descrlptlon of the Prior Art In the prior art, heating appliances, such as furnaces, hot water heaters, cooking devices, etc., operating from gaseous or vaporous fuels, are extremely well known. A variety of fuels are com-monly used by such appliances Includlng natural gas, propane, butane and other slmilar fuels. It has been common practlce for a pilot to be left burning contlnuously at a relatively low gas consumption rate, in order that the appliance can (manually or automatically) be placed into full operation conveniently and without significant delay.
Recently, attention has been focused on measures for the conservation of fuels however, and this has tended to spawn various-new hardware for starting of such gas appliances without the need for a con-tinuous burning pilot.
Among these devices are those which provide for ignition of the appliance main burner by means of an electrlcally heated element, .
or by means of a spark gap. Spark gaps have the advantage of not re-quiring a heat-up time, and they are relatively economical of electrical energy For the sake of reliability however, some recent devices of the type have provlded for electrical ignition, by spark gap for example, of a gas fired pilot, the said gas-fired pilot in tUM operatlng to ignite the main burner or burners of the appliance. The art concerning gas fired pilots is developed to the point where main burner ignition is very - ~
-~ E. A. Carlson 4 ``- 103710'7 reliably effected. Direct spark ignition of a main burner has been undertaken in this art but may introduce some prob-lems such as excessive gas collection before ignition.
At least one prior art device is known which involves the use of spark ignition of a gas fired pilot. Such a device is described in U. S. Patent 3,662,185, entitled "Spark Generator and Components Therefor". That device makes use of the so-called flame rod (known in these arts per se) which mav act as one spark electrode and also as an electrode providing flame rectification or conduction as the pilot flame plays on the flame rod. The fact that such conduction occurs and is unipolar has given rise to the term "flame rectification". The resistance of the flame path is on the order of several megohms, and that resistance is employed as an element in a circuit for disabling the self-recycling spark voltage generator while the pilot is lighted. The indicated prior art device makes use of a voltage trippler as a power source for a relaxation oscillator employing an element such as a neon tube. Such gas discharge devices normally reguire somewhat higher operating voltages than are provided by the low voltage direct current power sources common in recreational vehicles and the like. That reference derives the necessary higher direct current source voltage by a relatively expensive method. The manner in which the present invention builds upon this reference to provide a unique and significantly more efficient and cost effective igniting system- will be evident as this descriptlon proceeds.
.; f , , E. A. Carlson 4 `- 10371~7 Another reference of interest is United States Patent No. 3,877,864 issued April 15, 1975.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a spark pilot igniter for gaseous and vaporous fuel systems including a fuel operated pilot, said igniter including a spark gap adjacent to said pilot, said igniter being opera-tive from a low voltage first direct current power source, comprising: a ringing choke oscillator connected to said first 10 direct current power source for producing a second direct current voltage source higher than said power source; charg-ing means including a first capacitor and a series resistance, said first capacitor being connected to charge from said second direct current voltage source; a first solid state switch device having main current carrying electrodes includ-ing an anode and a cathode and a control electrode capable of controlling the effective resistance between said anode and cathode from a relatively low to a relatively high value; a high ratio step-up transformer having primary and secondary : 20 windings, said primary winding being connected in series with said main current carrying electrodes of said first solid state switch device and said second direct current voltage source, said secondary winding being operatively con-nected to said spark gap; a relaxation osciilator connected to ~5 said second voltage source for producing periodic output -~ E. A. Carlson 4 103710~
voltage pulses, said voltage pulses being connected to said first solid state switching device control electrode to cause said resistance between said anode and cathode to assume said low effective resistance value momentarily, thereby to produce a pulse of current in said transformer primary and a corre-sponding stepped-up voltage applied to said spark gap contem-poraneously with the occurrence of said relaxation oscillator output pulses, thereby to effect ignition of said pilot:
means including a flame rod extending at least partially into the flame of said pilot, said flame rod ~eing connected to provide a flame current path through said flame from a terminal of said transformer secondary; and a return current path for the other terminal of said transformer secondary con-nected to a point in the circuit of said relaxation oscillator such that said flame current reduces the effective supplyvoltage to said relaxation oscillator below the point of opera-bility of said relaxation oscillator, said ringing choke oscillator comprising a first series current path having in order, a forward poled diode, an inductor, first and second resistors, all in series across said first power source, said diode connecting to a first terminal of said first power source and the second of said resistors con-necting to a second terminal of said first power source;
-3a-~,;
.~. ,s/i A
' _ - E. A. Carlson 4 ~037~7 and including means comprising a tap along the winding of said inductor and.a second solid state device.having an emitter-collector current path and a base electrode, said emitter-collector current path being connected from said S inductor tap to said second terminal of said first power source, and said base electrode being connected to the junc-tion of said resistors, thereby to produce oscillatory pulses of relatively high peak voltage at the:junction of said in-. ductor and the first of said resistors with respect to said first power source second terminal.
... ~~ .
BRIEF DESCRIPTION OF THE DRAWING
In the accompanying.drawing which illustrates an ex-emplary embodiment of the present invention:
The single figure is an electrical schematic diagram.
! 15 DESCRIPTION OP THE PREFERRED EMBODIMENT
- -Referring to the drawing, the structure and operation of the device of the invention will be described.
The invention.is particularly useful, efficient, and economical in connection with electrical power sources as represented by the block Eo~ such as are typically used in recreational vehicles. Although the invention is not so limited, a typical embodiment designed for operation from the 12 volt storage battery system of a recreational vehicle will be described.
'` .
:~
~ 3b-.
E. A. Carlson 4 103710~7 On the drawing, the circuitry to the right of Cl (the filter/
sto~age capacitor) requires a direct current voltage on the order of approximately 90 to 100 volts for satisfactory operation. The circuitry to tha left of Cl (and including Cl itself) is devoted to the development of this higher direct current voltage from the 12 volt source .
The aforementioned U.S. Patent 3,662,185, shows and describes the relaxation oscillator/pulser circuit for operating the spark igniter across the gap between the flame rod FR and the pilot light grounded enclosure PL. Basically, this circuLt operates to charge up a capacitor ~ C2, through a large valùe resistor R4, to the firing voltage of neon lamp Ll, which is typically on the order of 60 to 75 volts. The firing of L1 essentially connects C2 across R6, the latter beLng a relatively low value reslstor, through a current limiting resistor R5 and diode D3 which acts as a current "check-valve". Thus, a pulse is provided to the gate electrode of the silicon controlled rectifier CRl, bringing that device into conduction.
That conduction and the resultant current pulse occurs around a loop in-cluding Cl, the primary or pulse transformerTl, and the CRl anode/cathode main current path. The impedance or internal reslstance of the ringing-choke converter, Is such that it could not supply or sustain such a current, con-sequently the said current pulse is sustained substantially only until the charge of capacitor Cl is appreciably decreased. At that time, both the effective voltage across the anode cathode circuit of CRl and the CRl gate electrode triggering pulse from the neon lamp relaxation oscillator will have -both greatly decreased. Extinguishment of Ll through the "dumping" of C2 charge, starts a new cycle of recharing of C2 throughR4. The diode D3 prevents the flow of any back current from the CRl gate electrodeduring transient conditions accompanying the spark discharge between FR and PL.
Transformer Tl, which has a relatively large step-up ratio, is capable of producing a secondary voltage on the order of 16 Kilovolts to produce the 3~ spark discharge.
E. A. Carlson 4 It will be noted that, as is known, the flame rod FR, acts as an anode of a high resistance diode in coope~ation with the flame itsel~ and the grounded housing of the pLlot PL. Since the relaxation oscillator/sparking pulser circuitry (i.e., that to the right of Cl) is to be inhibited, or disabled, once the pilot flame is actually established, use is made of the so-called flame rectification characteristic just described. The forward resistance of this "flame diode" is in the megohm range and, in order to serve the purpose of inhibiting the relaxation oscillator/pulser, must be supplied with current poled at a positive potentlal with respect to ground as applLed to FR.
In the circuit of the drawing, the junction of C2, r 1 and R4 also provides a return for the secondary of the pulse transformer Tl.
Between spark cycles, the "flame diode" (assuming the pllot flame is extant) permlts some current through R4 and the sald secondary of Tl lS to pass through the said flame diode. The value of R4 is chosen so that the flame conduction reslstance and the said R4 act as a dlvider, reducing the potential at the said junction of Ll, C2 and R4 to a value below the mlnimum firing potential of Ll.
From the foregolng information, it will be seen that the source constituted by the DC-to~C converter (ringing-choke ascillator) to the left of Cl, must be positive at the upper end of R4. While there are many ways that this can be accomplished with a DC~DC converter, it is essential that it be accomplished in an efficient, low cost manner.
Since, as already indicated, a grounded negative storage battery source (Eo) of 12 volts, for example, is also an initial constraint, the DC-to-DC must handle this situation without resorting to multi-wlnding trans-formers, or other more expensive expedients.
Before describing the ringlng-choke converter of the present invention in detail, it may be useful to point out that prior art ringing-choke .: , .
-E. A. Carlaon 4 10371~7 converter circuits for general application, are commonl~ more complex.
See, for example, the text entitl~ CA Silicon Power Circuits Manual"
(a publication of Radio Corporation sf America as part of their technical series SP-51, dated 1969). Page 168 describes a typical prior art ringing-choke inverter (or converter) circuit.
The ringing-choke oscillator circuit of the present invention includes only a tapped tank coil or auto transformer T2, a single PNP
transistor, a pair of diodes, a filter/storage capacitor and three resistors.
It will be apparent to those skilled in the electronic circuit arts that a PNP translstor Q1 is appropriate for the polarities indicated and aforementloned. In an initial condition, current from the positive pole of the source Eo passes through diode Dl through T2. Most of thls current follows the tap through the emitter of Ql and passes through the emitter/collector current path of the said Ql to the negative Eo terminal (l.e., ground). The resistors R1 and R2 constitute a base biasing arrangement for Ql, -such that, In the qulescent condition, Q1 is biased Into a conducting condition substantially below saturatlon.
- The growth of current through the upper portion of T2, l e., from Dl to the tap, induces a signal into the lower half of T2 which is regenerative in polarity as It reaches the base of Ql. That is, this regenerative condition Is extant until Q1 beglns to saturate, at which timethe rate of current growth in the upper portiosl of T2 falls off. As is well understood in electromagnetic circuit theory, the induced regenerative signal afore-mentioned in the lower portlon of T2 then quickly reverses and becomes degenerative, hastening the cutoff of Ql until that portion of the cycle runs its course. Subsequently the reconduction of Ql starts the cycle ~; over again. Thus, the junction of R2 and R3 provides an alternating signal which is rectified by D2 through current limiting resistor R3 in order to charge capacitor Cl .
E. A. Carlson 4 ' 103qlO7 Although the flame conduction referred to h~reinbefore is effective to inhibit the further functLon o~ the relaxation oscillator/
pulser by reducing thP voltage at the junction of R4 and C2, the ringing-choke oscillator continues ,to operate and maintain the fully charged c~nditi~3n of filter/storage capacitor Cl. .
Typical circuit values for the em~odiment of the flgure are given in Table I below. A typical operating frequency for the said ringing-choke oscillator is 20KHz.
, ' , ' ' .
TABLE OF TYPrCAL COMPO,IJENT TYPES AND VALUES
Dl, D2 and D3 ' IN4002 Ql MPSD 51 (Motorola) Rl 4.7KQ:
R2 470 n ., R3 150 S~ .
R4 ' 22 Megohms R5 IK n R6 . -lK Q
CRI SCR
~;, ' 2 0 . ' C l . 2 . 2 ,u fd C2 0. 001P fd Certain modificatlons and variations will suggest themselves to those sk}lled in these arts, Accordingly, it is not intended that the ~: scope of the invention should be limited by the drawing or this
2 5 de scFiption .
~ WTO:dr - July 25, 1974
~ WTO:dr - July 25, 1974
Claims (7)
1. A spark pilot igniter for gaseous and vaporous fuel systems including a fuel operated pilot, said igniter including a spark gap adjacent to said pilot, said igniter being operative from a low voltage first direct current power source, comprising:
a ringing choke oscillator connected to said first direct current power source for producing a second direct cur-rent voltage source higher than said power source;
charging means including a first capacitor and a series resistance, said first capacitor being connected to charge from said second direct current voltage source;
a first solid state switch device having main current carrying electrodes including an anode and a cathode and a con-trol electrode capable of controlling the effective resistance between said anode and cathode from a relatively low to a rela-tively high value;
a high ratio step-up transformer having primary and secondary windings, said primary winding being connected in series with said main current carrying electrodes of said first solid state switch device and said second direct current voltage source, said secondary winding being operatively connected to said spark gap;
a relaxation oscillator connected to said second voltage source for producing periodic output voltage pulses, said voltage pulses being connected to said first solid state switch-ing device control electrode to cause said resistance between said anode and cathode to assume said low effective resistance value momentarily, thereby to produce a pulse of current in said transformer primary and a corresponding stepped-up voltage applied to said spark gap contemporaneously with the occurrence of said relaxation oscillator output pulses thereby to effect ignition of said pilot;
means including a flame rod extending at least partially into the flame of said pilot, said flame rod being connected to provide a flame current path through said flame from a terminal of said transformer secondary;
and a return current path for the other terminal of said transformer secondary connected to a point in the cir-cuit of said relaxation oscillator such that said flame current reduces the effective supply voltage to said relaxation oscilla-tor below the point of operability of said relaxation oscillator, said ringing choke oscillator comprising a first series current path having in order, a forward poled diode, an inductor, first and second resistors, all in series across said first power source, said diode connecting to a first terminal of said first power source and the second of said resistors connecting to a second terminal of said first power source;
and including means comprising a tap along the winding of said inductor and a second solid state device having an emitter-collector current path and a base electrode, said emitter-collector current path being connected from said induc-tor tap to said second terminal of said first power source, and said base electrode being connected to the junction of said resistors, thereby to produce oscillatory pulses of relatively high peak voltage at the junction of said inductor and the first of said resistors with respect to said first power source second terminal.
a ringing choke oscillator connected to said first direct current power source for producing a second direct cur-rent voltage source higher than said power source;
charging means including a first capacitor and a series resistance, said first capacitor being connected to charge from said second direct current voltage source;
a first solid state switch device having main current carrying electrodes including an anode and a cathode and a con-trol electrode capable of controlling the effective resistance between said anode and cathode from a relatively low to a rela-tively high value;
a high ratio step-up transformer having primary and secondary windings, said primary winding being connected in series with said main current carrying electrodes of said first solid state switch device and said second direct current voltage source, said secondary winding being operatively connected to said spark gap;
a relaxation oscillator connected to said second voltage source for producing periodic output voltage pulses, said voltage pulses being connected to said first solid state switch-ing device control electrode to cause said resistance between said anode and cathode to assume said low effective resistance value momentarily, thereby to produce a pulse of current in said transformer primary and a corresponding stepped-up voltage applied to said spark gap contemporaneously with the occurrence of said relaxation oscillator output pulses thereby to effect ignition of said pilot;
means including a flame rod extending at least partially into the flame of said pilot, said flame rod being connected to provide a flame current path through said flame from a terminal of said transformer secondary;
and a return current path for the other terminal of said transformer secondary connected to a point in the cir-cuit of said relaxation oscillator such that said flame current reduces the effective supply voltage to said relaxation oscilla-tor below the point of operability of said relaxation oscillator, said ringing choke oscillator comprising a first series current path having in order, a forward poled diode, an inductor, first and second resistors, all in series across said first power source, said diode connecting to a first terminal of said first power source and the second of said resistors connecting to a second terminal of said first power source;
and including means comprising a tap along the winding of said inductor and a second solid state device having an emitter-collector current path and a base electrode, said emitter-collector current path being connected from said induc-tor tap to said second terminal of said first power source, and said base electrode being connected to the junction of said resistors, thereby to produce oscillatory pulses of relatively high peak voltage at the junction of said inductor and the first of said resistors with respect to said first power source second terminal.
2. Apparatus according to claim 1 further including a third resistor and second forward poled diode in series, con-nected to said oscillatory pulses, and a second capacitor con-nected on one terminal through said series third resistor and second diode to said oscillatory pulses and on the other ter-minal to said first power source second terminal, thereby to produce said second voltage source available across said second capacitor.
3. Apparatus according to claim 2 in which said first and second resistors are selected to provide a base electrode bias for said second solid state device to produce a normally conducting condition of said emitter-collector current path.
4. Apparatus according to claim 1 in which said first and second resistors are selected to provide a base electrode bias for said second solid state device to produce a normally conducting condition of said emitter-collector current path.
5. Apparatus according to claim 2 in which said inductor tap is located such that, so long as said second solid state device emitter-collector current is increasing a regen-erative signal is induced in the portion of said inductor not in series with said emitter-collector current path, and so that, upon saturation of said second solid state device, a degenera-tive signal is induced in said portion of said inductor not in series with said emitter-collector current path.
6. Apparatus according to claim 5 in which said first direct current power source first terminal is the positive ter-minal and said second terminal thereof is the negative terminal.
7. Apparatus according to claim 6 in which said second solid state device is a PNP transistor the collector electrode of which is the grounded terminal of said first and second power sources.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US492459A US3877864A (en) | 1974-07-29 | 1974-07-29 | Spark igniter system for gas appliance pilot ignition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1037107A true CA1037107A (en) | 1978-08-22 |
Family
ID=23956342
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA232,031A Expired CA1037107A (en) | 1974-07-29 | 1975-07-22 | Spark igniter system for gas appliance pilot ignition |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3877864A (en) |
| CA (1) | CA1037107A (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4015928A (en) * | 1976-01-23 | 1977-04-05 | International Telephone And Telegraph Corporation | Heating system |
| US4418375A (en) * | 1981-08-07 | 1983-11-29 | Hunter Investment Company | Solid state ignition system |
| HU197130B (en) * | 1985-04-11 | 1989-02-28 | Adam Kovacs | Circuit arrangement for generating pulses |
| DE4309454C2 (en) * | 1993-03-24 | 1997-03-06 | Dungs Karl Gmbh & Co | Ionization flame monitor |
| US5995352A (en) * | 1994-11-29 | 1999-11-30 | Erico Lightning Technologies Pty. Ltd. | Ignition apparatus and method |
| FR2751729B1 (en) * | 1996-07-25 | 1998-10-09 | Sdecc | BURNER SECURITY DEVICE FOR FLAME IGNITION, FLAME DETECTION AND GAS INTAKE CONTROL |
| ITTO980398A1 (en) * | 1998-05-12 | 1999-11-12 | Miller Europe Spa | ELECTRIC GAS LIGHTER. |
| JP3811681B2 (en) * | 2002-06-12 | 2006-08-23 | 日本碍子株式会社 | High voltage pulse generator |
| JP4418212B2 (en) * | 2003-11-21 | 2010-02-17 | 日本碍子株式会社 | High voltage pulse generator |
| US7372005B2 (en) * | 2004-09-27 | 2008-05-13 | Aos Holding Company | Water storage device having a powered anode |
| JP4538305B2 (en) * | 2004-12-07 | 2010-09-08 | 日本碍子株式会社 | Discharge device |
| US20070242492A1 (en) * | 2006-04-18 | 2007-10-18 | Ngk Insulators, Ltd. | Pulse generator circuit |
| US20090061367A1 (en) * | 2007-08-28 | 2009-03-05 | Andrew Robert Caves | Appliance having a safety string |
| US8388339B2 (en) * | 2008-12-18 | 2013-03-05 | Robertshaw Controls Company | Single micro-pin flame sense circuit and method |
| US9494320B2 (en) | 2013-01-11 | 2016-11-15 | Honeywell International Inc. | Method and system for starting an intermittent flame-powered pilot combustion system |
| US10208954B2 (en) | 2013-01-11 | 2019-02-19 | Ademco Inc. | Method and system for controlling an ignition sequence for an intermittent flame-powered pilot combustion system |
| US11236930B2 (en) | 2018-05-01 | 2022-02-01 | Ademco Inc. | Method and system for controlling an intermittent pilot water heater system |
| US11739982B2 (en) | 2019-08-14 | 2023-08-29 | Ademco Inc. | Control system for an intermittent pilot water heater |
| US11656000B2 (en) | 2019-08-14 | 2023-05-23 | Ademco Inc. | Burner control system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3377125A (en) * | 1966-06-16 | 1968-04-09 | American Gas Ass | Electrical ignition system for gaseous fuel burners and the like |
| US3441356A (en) * | 1967-09-12 | 1969-04-29 | Fenwal Inc | Pulsed spark gas ignition and fuel control system |
| US3632285A (en) * | 1969-12-31 | 1972-01-04 | Fenwal Inc | Gas igniter system |
| US3662185A (en) * | 1970-10-01 | 1972-05-09 | Itt | Spark generator and components therefor |
-
1974
- 1974-07-29 US US492459A patent/US3877864A/en not_active Expired - Lifetime
-
1975
- 1975-07-22 CA CA232,031A patent/CA1037107A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US3877864A (en) | 1975-04-15 |
| AU8341075A (en) | 1977-01-27 |
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