Abstract: A fuel burner primary control with a pre-purge and extended ignition function has been disclosed. The system has been disclosed as an oil burner which utilizes a voltage regulator to insure that adequate power is supplied to the device and with a time delay on the application of potential to the ignition and oil source to allow for a pre-purge interval. The ignition source is also time delayed to insure a stable flame before the ignition is deenergized.

Abstract: Burner control apparatus includes a control device for actuating an ignition control means, and a timing circuit for providing an ignition timing interval which extends beyond flame detection for a timed interval. The timing circuit is actuated in response to a request for burner operation and the control device is energized in response to the actuated timing circuit. The control device is maintained energized if a signal from the flame sensor is received before the end of the ignition timing interval, and the control device is deenergized and lockout circuitry is energized in the absence of a signal from the flame sensor. Main fuel supply is delayed for the timed interval to provide pilot flame stabilization.

Abstract: A burner control apparatus for use with a furnace installation that has an operating control to produce a request for burner operation, a flame sensor to produce a signal when flame is present in the monitored combustion chamber, and one or more devices for control of ignition and/or fuel flow. The burner control apparatus comprises lockout apparatus for de-energizing the control apparatus, a control device for actuating the ignition and/or fuel control devices, and a timing circuit that provides four successive and partially overlapping timing intervals of precise relation, including a purge timing interval, a pilot ignition interval, and a main fuel ignition interval. The present invention further includes a burner control system which verifies the proper operation of certain sensors in a burner or furnace including particularly the air flow sensor.

Abstract: Disclosed is a combustion control apparatus of digital type, in which a fault is warned of unless ignition resumes in a predetermined time after the start of igniting operation in the reignition when fuel flaming is extinguished during combustion. The predetermined time is called safety time and the combustion control apparatus can exactly obtain such a required time or period as the safety time. With such a digital type combustion control apparatus, the safety timer for establishing the safety time comprises flip-flops adapted to count reference clock pulses. In this apparatus, the circuit for generating the reference clock pulses is set and reset by the flame extinction signal to synchronize the clock pulses and the flame extinction signal so that the safety time may be free from error. This concept can be applied to determine the prepurge time.

Abstract: This invention relates to a particularly safe electrical control device for a gas or oil-fired heating appliance comprising a plurality of sub-circuits each carrying out part of a start-up sequence for the appliance, and arranged so that should any sub-circuit fail, the start-up sequence ceases.Parts of the control device are similar to those shown in British Patent Specification No. 1,314,185. (U.S.Pat. No. 3,674,410).

Abstract: A fuel burner sequencing means is disclosed which utilizes a bistable or alternate action switching means for safety checking. The bistable switching means is specifically disclosed as a bistable relay that operates at the start of the cycle, and at the end of the cycle to check the operability of the safety checking means. This same bistable relay means is used as a lockout means in the event of the failure of flame when a flame should exist in the burner, or when a flame is indicated and none should be present.

Abstract: A fuel burner sequencing device is disclosed which utulizes cam operated switches in conjunction with relays to program the initiation and safe operation of a fuel burner. The sequencing device or means provides for a normal start up and ignition of a fuel burner, and then provides for a postpurge pilot operation for a normal shutdown of the burner. The postpurge pilot operation activates the pilot burner during the time the main burner is on thereby lighting the pilot burner before the main burner is turned off. The pilot burner is retained in a burning state for a short period after the main burner has been turned off to burn off any residual fuel before the sequencing device or means completes its sequence and is ready for the initiation of a new operating cycle.

Abstract: There has been provided a burner control system including apparatus adapted for controlling fuel burner systems for firing furnace sections of steam generators in accordance with any one of a plurality of predetermined subsystem specifications such as fuel safety, ignition and shutdown sequences. The system includes a plurality of sets of logical function means (LFM) having inputs and outputs, responsive to selected ones of the parameters of the system for producing output control and indication signals respectively. Each LFM comprises one solid state control circuit card for performing each logical function in accordance with the specification such as fuel trip, burner ignition and shutdown etc. Each control circuit card is fabricated to include functional logic circuits of the AND, OR, NAND, NOR, etc.