The Walter Kidde Company Limited

Kidde, Inc.

Other

William J Riordan

Richard A Cunha

Carl W Walter

William J Bowles

Charles Collins

A control system including a valve for controlling the flow of fuel to a burner, a resistive heater element connected between first and second terminals and disposed for igniting fuel emanating from the burner, an isolation transformer comprising a heater secondary winding connected to the first and second terminals so as to provide heating current to the heater element, and an electrode spaced from the heater element in a zone occupied by flame emanating from the burner. Also included is a start-up circuit for opening the valve to provide fuel to the burner for ignition by the heater element and a flame sensing circuit comprising an ac source, coupling means connecting the ac source means between the electrode and one of the first and second terminals with the secondary winding connected to the first and second terminals, and a detector circuit for detecting the flow between the electrode and the heater element of current conducted by flame in the zone. Finally, a valve control circuit maintains the valve open in response to an output signal provided by the detector.

Fuel burner control system

A laboratory gas burner and control apparatus including a burner assembly made from electrically conductive material and adapted for positioning on a counter. Defined by the burner is an inlet for connection to a gas source and an outlet for feeding gas to a flame. An electrically operated valve controls the flow of gas to the burner outlet and an igniter is energizable by a power supply to ignite gas emanating from the burner outlet. Associated with the igniter is an activation circuit that produces either ignition periods during which the igniter is energized by the supply or non-ignition periods during which the igniter is deenergized. Initiation of each ignition period requires manipulation of a manual activation mechanism. Once ignited, the presence of flame at the burner outlet is detected by a flame sensing mechanism. A valve control circuit maintains the supply valve open only during either ignition periods or periods during which flame is detected by the sensing mechanism.

Laboratory burner apparatus

A fuel burner control system including a valve for controlling the flow of fuel to a burner, a resistive heater element for igniting fuel, a power supply for supplying current to the heater element, a flame sensing circuit comprising an ac source for supplying ac voltage to the heater element, and a detector for producing an output signal only in response to the flow through the heating element of current rectified by the flame, a valve control circuit for maintaining the valve open in response to the output signal, and a coupling circuit interconnecting the heating element with both the power supply and the sensing circuit and adapted to prevent the flow of current therebetween. By utilizing a coupling circuit that prevents the flow of current between the power supply and the flame sensing circuit, the resistive heater element can be efficiently and alternately used both as a fuel igniting mechanism and as an electrode for deriving current rectified by flame at the burner.

Fuel burner control apparatus

An electrical control system including a source of electrical power and an electrical load coupled together by a power switch having alternate circuit open and circuit closed conditions. A closure means activates the power switch to a circuit closed condition to produce power transmission between the source and the load in response to a closure signal produced by a condition responsive control circuit. Connected in series with the power switch is a protective switch also activated from a circuit open to a circuit closed condition in response to the closure signal. A sensing circuit produces a fault signal in response to a closed condition of the power switch and a simultaneous circuit open condition of the protective switch.

Fuel valve latch out system

The invention is a fuel burner system including an electrical control circuit for initiating fuel flow to a burner in response to a call-for-heat from a condition responsive sensor, and an electrical ignitor for igniting the fuel emanating from the burner. Combustion or purging air is directed to the burner by a fan, the integrity of which is monitored by a sensor circuit that produces a fault signal in response to rotation of the fan at any speed in a given range of speeds. An inhibit circuit inhibits the control circuit to prevent opening of a fuel supply valve in response to the presence of the fault signal. Fan rotation at speeds either above or below a predetermined normal range indicates a malfunction and results in the fault signal that prevents the initiation of fuel flow and a try for ignition.

Proving system for fuel burner blower

A burner control system including a valve for controlling the flow of fuel to a burner, a flame sensor for producing a flame signal in response to the presence of flame at the burner, a start-up circuit for producing a start-up signal, a control circuit for opening the valve to establish fuel flow in response to either the flame or start-up signal, and a timing capacitor first delays the generation of the start-up signal while charging during a predetermined purge period after energization of the start-up circuit and then terminates the start-up signal while discharging during a predetermined ignition period. A monostable electronic switch produces the start-up signal in response to the charge level on the timing capacitor and a valve initiator for opening the valve is powered by energy discharged by the timing capacitor during the ignition period.

Burner control system

Disclosed herein is a fuel burner control system with a purge timer having a current responsive control relay that is energized into an active state only by a given minimum input current level but can be maintained in that active state by a substantially lesser input current level. After connection to an electrical supply an activating circuit supplies the given input current level to the control relay only after a predetermined purge time period established by an electrical timer, after which a hold circuit supplies the lesser input current level maintaining the relay in its active state. A blower dissipates any residual fuel vapor in the vicinity of the burner during the purge period and only after its conclusion is fuel flow initiated and ignition attempted in response to contact closures effected in the relay's active state. In a preferred embodiment of the invention, the purge timer comprises an energy storage capacitor which is charged from the supply during the purge period after which a threshold device dumps the energy stored in the capacitor to produce the current level required to move the control relay into its active state.

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Shrewsbury, MA, United States of America

William J Riordan