Timer circuit for valve activation in oil burner system
AssigneeR. W. Beckett Corporation
InventorsJohn P. Graham, Victor J. Turk
Life of this patent
Estimating the term…
Abstract
The present invention is directed to an oil burner system having an electric cord set coupled between a controller and a valve associated with a pump. The electric cord set is operable to activate a solenoid valve associated with the pump for delivery of fuel oil to a nozzle of the burner. The electric cord set comprises a voltage or temperature independent timer circuit operable to activate the solenoid valve a predetermined period of time after a call for ignition signal is generated by the controller, wherein the predetermined time period is substantially constant with respect to variations in line voltage or in an ambient temperature in which the oil burner system resides.
Claims9
A timer circuit powered by a line voltage, comprising:
- a charging circuit having a voltage coupled thereto which is a function of the line voltage, and an output node which charges at a first rate when the line voltage is less than a predetermined threshold, and charges at a second rate when the line voltage is greater than the predetermined threshold, wherein the second charging rate comprises a modulation of the first charging rate;
- a reference voltage circuit operable to generate a reference voltage;
- a comparison circuit operable to generate a signal indicative of a comparison between the output node of the charging circuit and the reference voltage, wherein a time period between when the line voltage is applied to the charging circuit and the signal indication that the output node has exceeded the reference voltage represents a delay time.
A timer circuit powered by a line voltage, comprising:
- a first charging circuit having an output node which charges at a first charging rate, wherein the first charging rate is a function of the line voltage;
- a second charging circuit having an output node which charges at a second charging rate, wherein the second charging rate is a function of the line voltage, and wherein the second charging rate is different than the first charging rate;
- and
- a comparison circuit operable to generate a control signal which is indicative of when the output nodes of the first and second charging circuits are equal, and wherein a time period between when the line voltage is applied to the first and second charging circuits and the control signal indication comprises a delay time which is substantially independent of a magnitude of the line voltage.
Dependencies are inferred from the claim text.