US 4,359,315 AGranted

Apparatus for fuel ignition system including complete cycling of flame relay prior to trial for ignition

AssigneeJohnson Controls GmbH

InventorRussell B. Matthews

Life of this patent

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Abstract

When a call for heat is established, a flame relay is actuated for a predetermined time by means of a cycling timer. Upon this initial actuation, the flame relay inhibits a checking relay and initializes a trial-for-ignition (or simply "ignition") timer. After the cycling timer times out and the flame relay has been completely cycled, which establishes operativeness of the flame relay and flame sensing circuitry, the checking relay is enabled and actuated for the ignition period. The checking relay then actuates the pilot valve and a spark generator to start a pilot flame. If a flame is sensed, before the ignition timer times out, the flame relay actuates the main valve and establishes a holding current for the ignition timer so that the checking relay continues to be energized. If a flame is not sensed during the trial period, the ignition timer disables the checking relay, thereby de-energizing the pilot valve before the main valve is opened. If there is a fault in the flame relay or flame sensing circuitry, the checking relay is inhibited from operating. Both timers are preferably electronic timing circuits using capacitors in such a manner that circuit faults do not cause system malfunction. In an alternative embodiment, separate flame sensing circuits control the operation of the flame relay and the ignition timer.

Claims8

Dependent claims

In a fuel ignition system including a pilot valve operable when energized to supply fuel to a pilot outlet for ignition by sparks provided by a spark generating means to provide a pilot flame, and a main valve operable when energized to supply fuel to a main burner for ignition by the pilot flame, a control arrangement comprising:

activate means for generating a start signal to initiate an ignition cycle;
timing circuit means including a capacitor and circuit means for permitting said capacitor to be charged by said start signal to generate a timing signal during a trial for ignition interval defined by the charging time of the capacitor;
first switching means for controlling the operation of said pilot valve;
actuating means responsive to said timing signal to enable said first switching means to energize said pilot valve for said trail for ignition interval;
said timing circuit means terminating said timing signal at the end of said trial for ignition interval to permit said actuating means to be disabled whereby said first switching means is disabled;
first flame sensing means operable when a flame is provided at said pilot outlet during said time interval to generate a control signal for application to said actuating means to cause said actuating means to maintain said first switching means operated after the end of said trial for ignition interval;
second flame sensing means;
and second switching means controlled by said second flame sensing means to be enabled when a flame is sensed during said trial for ignition interval to energize said main valve.

5 more elements

In a fuel ignition system including a pilot valve for supplying fuel to a pilot outlet for ignition by sparks provided by a spark generating means to establish a pilot flame, and a main valve for supplying fuel to a main burner for ignition by the pilot flame, a control arrangement comprising:

activate means operable to generate a start signal to initiate an ignition cycle;
switching means for controlling the operation of said pilot valve;
timing circuit means responsive to said start signal for defining a trial for ignition interval, said timing circuit means enabling said switching means to energize said pilot valve during said trail for ignition interval and disabling said switching means to deenergize said pilot valve at the end of said trial for ignition interval;
first flame sensing means operable when a flame is sensed during said trial for ignition interval to cause said timing circuit means to maintain said switching means enabled after said trial for ignition interval;
and second flame sensing means operable when a flame is sensed during said trial for ignition interval to effect the energization of said main valve.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/176,655Filed 11 Aug 1980 · division
Priority: 17 Apr 1978
Granted: 16 Nov 1982
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

F23N 5/203
With a time program acting through electrical means, e.g. using time-delay relays: using electronic means
F23N 5/123
Using ionisation-sensitive elements, i.e. flame rods: using electronic means
F23Q 3/004
Igniters using electrically-produced sparks: using semiconductor elements
F23N 2227/36
Ignition or checking: spark ignition, e.g. by means of a high voltage