Robertshaw Controls Company

Frederick J Geary

Frederick T Bauer

Jon Harold Bechtel

A heat exchanger system, a fuel control system therefor and methods of making the same are provided, the fuel control system having an electrical circuit means that comprises an ignition trial portion, a flame sensing control portion and a timer portion that comprises a counter having a plurality of outputs and a timer that clocks the output of the counter on each discharge of the timer, the timer portion also comprising a capacitor, a trial time resistor and a wait time resistor that are selectively placed in series with the capacitor by the counter when clocked to certain outputs by the timer to determine an ignition trial time period and a wait time period.

Heat exchanger system, fuel control system therefor, and methods of

A primary gas furnace control including a thermostatically controlled intermittent ignition system, the control being effective to monitor and control main gas valve action through use of flame rectification. The control features a slight delay on main valve dropout with flame failure and an extension of the ignition source into the main burner cycle to prevent nuisance recycling. If desired, the control may also include timed pilot valve, thermostat resettable, lockout as well as prepurge capability for use in applications requiring a furnace combustion chamber purge prior to an ignition cycle.

Primary gas furnace control

Heat exchanger system, fuel control system therefor

A hot surface ignition system for a gas furnace or the like, control device therefor and methods of making the same are provided, the system comprising a burner, a settable thermostat, an electrically operable gas valve, a control unit, and an electrically operable hot surface igniter disposed so as to be in the path of gas issuing from the burner that is adapted to be fed the gas from a source thereof through the gas valve when the control unit has been activated by the thermostat to operate the igniter and the gas valve in a certain sequence, the control unit having a lockout unit for deactivating the system should ignition of the gas issuing from the burner not take place by the end of the certain sequence, the control unit having a resetting unit for causing the control unit to be reactivated to be adapted to repeat the certain sequence of the system when the resetting unit is activated, the control unit being adapted to select the certain sequence to have one or more attempts of the control unit to ignite the gas at the burner before the lockout unit can deactivate the system, the resetting unit comprising a manually operated electrical switch that is remote from the thermostat and which must be manually moved to a certain position thereof to activate the resetting unit.

Hot surface ignition system for a gas furnace, control device therefor

The combination of a heating element and a control unit therefor and methods of making and of operating the same are provided, the heating element normally being adapted to be operated by the continuous full wave pulses of a certain high voltage alternating current source and the control unit being operatively interconnected to the heating element for operatively interconnecting the heating element to a high voltage alternating current source, the control unit having an arrangement for operating the heating element with a certain repeating pattern of skipped full half-wave pulses of the source when the source has a higher voltage than the certain source.

Combination of an igniter for a gas furnace and a control unit therefor

A low cost hot surface ignition system particularly adapted for use in gas furnaces and the like, the system including low voltage control and timing circuitry effective to control a gas valve and high voltage ignition circuitry incorporating a hot surface silicon carbide igniter disposed in the path of incoming gas and in the heat of the flame when ignition is achieved to effect flame rectification resulting in flame sensing. The system also provides fail-safe operation or safety shutdown of the associated furnace if ignition is not achieved or in the event of a failure of a component of the system.

Hot surface direct ignition system for gas furnaces

A control unit for a gas furnace that has an electrically operable pilot gas valve and an electrically operable main gas valve and a method of making the control unit are provided, the control unit comprising an electrical circuit having a gas valve section that comprises a silicon controlled rectifier and a first capacitor and a second capacitor so electrically interconnected together that the capacitors are adapted to be charged on each half wave cycle of a certain polarity of an alternative current source that is imposed on the circuit and that second capacitor is adapted to discharge through a relay coil that controls the gas valve to energize that relay coil only when the silicon controlled rectifier conducts, the silicon controlled rectifier being adapted to conduct only when the first capacitor is discharged, another section of the electrical circuit being adapted to discharge the first capacitor only on each half wave cycle of the other polarity of the alternative current source.

Fuel control unit for a gas furnace and method of making the same

Method of operating gas furnace igniter

A primary gas furnace control including a thermostatically controlled intermittent ignition system, the control being effective to monitor and control main gas valve action through use of flame rectification. The control features a slight delay on main valve dropout with flame failure and an extension of the ignition source into the main burner cycle to prevent nuisance recycling. If desired, the control may also include time pilot valve, thermostat resettable, lockout as well as prepurge capability for use in applications requiring a furnace combustion chamber purge prior to an ignition cycle.

A control unit for a gas furnace that has an electrically operable pilot gas valve and an electrically operable main gas valve and a method of making the control unit are provided, the control unit comprising an electrical circuit having a gas valve section that comprises a silicon controlled rectifier and a first capacitor and a second capacitor so electrically interconnected together that the capacitors are adapted to be charged on each half wave cycle of a certain polarity of an alternative current source that is imposed on the circuit and that the second capacitor is adapted to discharge through a relay coil that controls the gas valve to energize that relay coil only when the silicon controlled rectifier conducts, the silicon controlled rectifier being adapted to conduct only when the first capacitor is discharged, another section of the electrical circuit being adapted to discharge the first capacitor only on each half wave cycle of the other polarity of the alternative current source.

The combination of a heating element and a control unit therefor and methods of making and of operating the same are provided, the heating element normally being adapted to be operated by the continuous full-wave pulses of a certain high voltage alternating current source for a predetermined time period so as to provide a desired function thereof and the control unit being operatively interconnected to the heating element and having a first arrangement for operatively interconnecting the heating element to that certain high voltage alternating current source for the predetermined time period so as to provide a desired function thereof, the control unit having a second arrangement for operating the heating element with a certain repeating pattern of skipped complete half-wave pulses of another source of high voltage alternating current for the predetermined time period when that other source has a higher voltage than the certain source so that the heating element will not be adversely affected by the other source of higher voltage and will still provide the desired function thereof.

Heating element operating unit and method

A hot surface ignition system for a gas furnace and method of making the same are provided, the system comprising a high voltage circuit for being connected to a source of high voltage AC current, the high voltage circuit having a hot surface igniter therein and disposed in the path of gas issuing from a burner that is adapted to be fed gas from a source thereof through an electrically operated gas valve, a low voltage circuit for being connected to a source of low voltage AC current, the low voltage circuit having the gas valve therein and having a thermostatic switch therein controlling the energization of the low voltage circuit with the low voltage AC current, a first relay unit having contacts in the high voltage circuit and controlling the energizaiton of the igniter with the high voltage AC current, and another relay unit having contacts in the low voltage circuit and controlling the energization of the gas valve, the other relay unit comprising two separate relays respectively having contacts that are disposed in series in the low voltage circuit whereby the contacts of the two relays must be in the same condition thereof to energize the gas valve.

Growing community of inventors

Holland, MI, United States of America

Frederick J Geary