Direct spark ignition system with sampling flame sensor

Claim 2

In a fuel ignition system including valve means operable when energized to supply fuel to a fuel outlet, an ignition circuit for controlling the operation of said valve means and for igniting fuel discharged by said fuel outlet, said ignition circuit comprising ignition means operable when enabled to generate ignition sparks in the proximity of said fuel outlet, energizing means controlled by said ignition means to energize said valve means to supply fuel to said fuel outlet for ignition by said ignition sparks to establish a flame, sensing means enabled whenever a flame is established to disable said ignition means during a first period to inhibit the generation of ignition sparks and for enabling said ignition means to generate ignition sparks during a second period, and indicator means controlled by said energizing means to provide a first indication each time an ignition spark is generated, and to provide a second indication whenever said ignition means fails to produce ignition sparks during said second period.

Claim 3

A fuel ignition system as set forth in claim 1 wherein said energizing means includes first switching means enabled by said ignition means to effect operation of said indicator means, said ignition means being operable when enabled to provide control pulses for said first switching means effecting pulsed operation of said first switching means to permit said indicator means to operate each time an ignition spark is generated.

Claim 4

A fuel ignition system as set forth in claim 2 wherein said ignition means includes means for continuously enabling said first switching means whenever said ignition means fails to produce ignition sparks during said second period to provide continuous operation of said indicator means.

Claim 5

A fuel ignition system as set forth in claim 2 wherein said indicator means comprises a light emitting diode which is normally energized to emit light intermittantly in correspondance with the generation of ignition sparks and which is continuously energized whenever said ignition means fails to produce ignition sparks during said second period.

Claim 6

in a fuel ignition system including valve means for supplying gaseous fuel to a fuel outlet, an ignition circuit for controlling the operation of said valve means and for igniting fuel discharged by said fuel outlet, said ignition circuit comprising ignition means including electrode means, oscillator means, and enabling means for enabling said oscillator means to generate high voltage pulses for application to said electrode means to produce ignition sparks in the proximity of said fuel outlet, energizing means controlled by said ignition means for controlling said valve means to permit fuel to be supplied to said fuel outlet for ignition by said ignition sparks to establish a flame, flame sensing means including said electrode means operable when a flame is estblished to disable said enabling means for a first period whereby said oscillator means is disabled for said first period, said flame sensing means enabling said enabling means for a second period to thereby enable said oscillator means to generate further voltage pulses, and means enabled by said enabling means whenever said oscillator means fails to produce voltage pulses during said second period to enable said energizing means to control said valve means to Interrupt the supply of fuel to said fuel outlet.

Claim 7

in a fuel ignition system including valve means for supplying gaseous fuel to a fuel outlet, an ignition circuit for controlling the operation of said valve means and for igniting fuel discharged by said fuel outlet, said ignition circuit comprising ignition means including electrode means, oscillator means, and enabling means for enabling said oscillator means to generate high voltage pulses for application to said electrode means to produce ignition sparks in the proximity of said fuel outlet, energizing means controlled by said ignition means for controlling said valve means to permit fuel to be supplied to said fuel outlet for ignition by said ignition sparks to establish a flame, flame sensing means including said electrode means operable when a flame is estblished to disable said enabling means for a first period whereby said oscillator means is disabled for said first period, said flame sensing means enabling said enabling means for a second period to thereby enable said oscillator means to generate further voltage pulses, and means enabled by said enabling means whenever said oscillator means fails to produce voltage pulses during said second period to enable said energizing means to control said valve means to Interrupt the supply of fuel to said fuel outlet.

Claim 8

A fuel ignition system as set forth in claim 5 which includes means for supplying a DC energizing potential to said ignition circuit to permit said enabling means to normally extend a DC enabling signal to said oscillator means, said oscillator means being responsive to said DC enabling signal to produce AC voltage pulses in an output circuit thereof, first means for coupling said voltage pulses to said electrode means to effect the generation of ignition sparks and second means for coupling said voltage pulses to said energizing means to permit energization of said valve means.

Claim 9

A fuel ignition system as set forth in claim 6 wherein said oscillator means comprises semiconductor means, said first means comprising a transformer means having a first winding connected to extend siad DC enabling signal to a control input of said semiconductor means, a second winding connected to said electrode means, and third winding connected in an output circuit of said semiconductor means to permit said voltage pulses to be coupled to said second winding.

Claim 10

A fuel ignition system as set forth in claim 5 wherein said flame sensing means includes switching means operable when enabled to inhibit said enabling means and timing means operable whenever a flame is established to enable said switching means for said first duration and to disable said switching means for said second duration.

Claim 11

A fuel ignition system as set forth in claim 8 wherein said timing means includes capacitor means, first circuit means including said electrode means for permitting said capacitor means to charge over a first circuit path whenever a flame is established, and second circuit means including said switching means and said electrode means for permitting said capacitor means to discharge over a second circuit path to thereby operate said switching means, the discharge time of said capacitor means being greater than the charge time of said capacitor means whereby the first duration for which the oscillator means is inhibited is gerater than the second duration for which said oscillator means is enabled.

Claim 12

A fuel ignition system as set forth in claim 6 wherein said energizing means includes control means having first switching means responsive to said voltage pulses to provide further pulses for energizing a control winding of said valve means for operating said valve means to supply fuel to said fuel outlet for ignition by said ignition sparks, and sampling means having second switching means and timing means responsive to said further pulses to energize a further control winding of said valve means to maintain said valve means operated when a flame is established.

Claim 13

In a fuel ignition system including normally unoperated first valve means and normally operated second valve means connected in series between a fuel source and a fuel outlet, an ignition circuit for controlling the operation of said first and second valve means to supply fuel to said fuel outlet and for igniting fuel discharged by said fuel outlet, said ignition circuit comprising ignition means including first means operable when enabled to generate ignition sparks in the proximity of said fuel outlet for igniting fuel discharged by said fuel outlet to establish a flame, and second means for enabling said first means, energizing means controlled by said first means for effecting the operation of said first valve means, and sensing means operable whenever a flame is established to control said second means to disable said first means for a first period to thereby inhibit the generation of ignition sparks and to enable said first means for a second period to permit the generation of further ignition sparks, said ignition means including third means enabled by said second means whenever said first means fails to be enabled during said second period to effect deactivation of said second valve means to interrupt the supply of fuel to said fuel outlet.

Claim 14

In a fuel ignition system including normally unoperated first valve means and normally operated second valve means connected in series between a fuel source and a fuel outlet, an ignition circuit for controlling the operation of said first and second valve means to supply fuel to said fuel outlet and for igniting fuel discharged by said fuel outlet, said ignition circuit comprising ignition means including first means operable when enabled to generate ignition sparks in the proximity of said fuel outlet for igniting fuel discharged by said fuel outlet to establish a flame, and second means for enabling said first means, energizing means controlled by said first means for effecting the operation of said first valve means, and sensing means operable whenever a flame is established to control said second means to disable said first means for a first period to thereby inhibit the generation of ignition sparks and to enable said first means for a second period to permit the generation of further ignition sparks, said ignition means including third means enabled by said second means whenever said first means fails to be enabled during said second period to effect deactivation of said second valve means to interrupt the supply of fuel to said fuel outlet.

Claim 15

A fuel igniTion system as set forth in claim 11 which includes indicator means controlled by said energizing means to provide an indication each time a spark is generated.

Claim 16

A fuel ignition system as set forth in claim 11 wherein said energizing means includes control means having first switching means enabled by said first means to energize a pickup winding of said first valve means to operate said first valve means to supply fuel to said fuel outlet for ignition by said ignition sparks, and sampling means including second switching means enabled by said first switching means to energize a hold winding of said first valve means to maintain said first valve means operated when a flame is established.

Claim 17

A fuel ignition system as set forth in claim 11 wherein said energizing means includes control means having first switching means, said first means including means for generating control pulses to enable said first switching means to provide current pulses for effecting operation of said first valve means, said first switching means being disabled during said first period when the flame is established, and sampling means including second switching means and timing means responsive to said current pulses to provide a potential for enabling said second switching means to maintain said valve means operated during said first period.

Claim 18

A fuel ignition system as set forth in claim 14 which includes third switching means energized by said first switching means to deactivate said second valve means whenever a flame fails to be established after a predetermined number of control pulses have been supplied to said first switching means by said first means.

Claim 19

A fuel ignition system as set forth in claim 15 which includes indicator means energized by each current pulse provided by said first switching means.

Claim 20

A fuel ignition system as set forth in claim 16 wherein said third means is enabled by said second means to continuously energize said second switching means whenever said first means fails to produce said control pulses during said second period to thereby effect continuous energization of said indicator means.