Fuel ignition control arrangement employing dual flame sensors
AssigneeJohnson Controls GmbH
InventorRussell B. Matthews
Life of this patent
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Abstract
A control arrangement for a pilot ignition type fuel ignition system includes a first switch device which effects energization of a pilot valve at the start of an operating cycle to supply fuel to a pilot outlet for ignition to provide a pilot flame. The first switch device is enabled by a control circuit which in turn is enabled over a path provided by a second switch device. The second switch device is enabled by a flame sensing circuit when a pilot flame is established and operates to effect energization of a main valve and to interrupt the enabling path for the control circuit, and a further flame sensing circuit maintains the first switch device, and thus the pilot valve, operated following operation of the second switch device.
Claims17
In a fuel ignition system including valve means having at least one fuel supply valve operable when energized to supply fuel to a burner apparatus for ignition to provide a flame, a control arrangement comprising activate means, control means responsive to said activate means to provide a control signal, first switching means enabled by said control signal to prepare an energizing path for the fuel supply valve, second switching means operable to complete the energizing path for the valve to effect energization of the valve and to prevent said control means from providing its control signal, first flame sensing means for maintaining said second switching means operated when a flame is provided at said burner apparatus, and second flame sensing means operable when a flame is provided at said burner apparatus to provide a further control signal for maintaining said first switching means enabled after said control means is prevented from providing its control signal.
In a fuel ignition system including a pilot valve operable when energized to supply fuel to a pilot outlet of a burner apparatus for ignition by sparks provided by a spark generator to provide a pilot flame, and a main valve operable when energized to supply fuel to a main burner of the burner apparatus for ignition by the pilot flame, a control arrangement comprising first switching means for controlling the operation of the pilot valve, second switching means for controlling the operation of said main valve, activate means, control means enabled by said activate means over a path provided by said second switching means to provide a control signal, said first switching means being enabled by said control signal to effect energization of said pilot valve, first flame sensing means operable when a flame is provided at said burner apparatus to enable said second switching means to effect energization of said main valve and to interrupt said enabling path for said control means to prevent said control means from providing its control signal, and second flame sensing means operable when a flame is provided at said burner apparatus to provide a further control signal for maintaining said first switching means enabled after said control means is prevented from providing its control signal.
In a fuel ignition system including a pilot valve operable when energized to supply fuel to a burner for ignition to provide a pilot flame, and a main valve operable when energized to supply fuel to said burner for ignition by the pilot flame, a control arrangement comprising first switching means for controlling the operation of the pilot valve, second switching means for controlling the operation of said main valve, control means operable at the start of an ignition cycle to enable said first switching means to energize said pilot valve, timing means enabled by said control means to permit said pilot valve to remain energized for a predetermined interval of time and to cause said pilot valve to be deenergized at the end of said time interval, first flame sensing means operable when a flame is provided at said burner during said time interval to enable said second switching means to energize said main valve and to disable said control means, said timing means being prevented from deenergizing said pilot valve when said second switching means is enabled, and second flame sensing means operable when a flame is provided at said burner during said time interval to maintain said first switching means enabled after said control means is disabled.
Dependencies are inferred from the claim text.