Primary control system for furnaces

Claim 2

In an electrical primary control system for furnaces, the combination including burner control means adapted to be connected to a main line source of AC current, a low voltage control circuit including burner ignition detection means, means providing a substantially lower voltage than line voltage in said control circuit, means in said low voltage control circuit including solid state means effective to actuate said burner control means in response to a signal from said ignition detection means, and means interfacing between saaid low voltage control circuit and said burner means, said interfacing means comprising a pair of resilient magnetic contact members disposed in normally spaced overlapping relationship and adapted to make electrical contact therebetween under the influence of magnetic flux, a pair of electrically insulated concentric coils encompassing said contact members, the magnetic flux generated by said coils being additive whereby energization of both of said coils concurrently is effective to move said members into electrically contacting relationship and energization of one of said coils is sufficient to maintain said members in electrically contacting relationship, and a calibrated resistance wire electrically connected in parallel circuit across at least one of said coils.

Claim 3

The combination as set forth in claim 1, wherein said low voltage control circuit includes a DC supply for one of said coils.

Claim 4

The combination as set forth in claim 2, wherein said solid state means controls the flow of current through the other of said coils.

Claim 5

The combination as set forth in claim 3 wherein said ignition detector means controls the flow of current through said solid state means.

Claim 6

The combination as set forth in claim 4 wherein said interfacing means controls the energization of said burner control means.

Claim 7

In an electrical primary control system for furnaces, the combination including burner control means adapted to be connected to a furnace burner connected to a main line source of AC current, a low voltage control circuit including burner ignition detection means and energy conversion means, means providing a substantially lower voltage than line voltage in said control circuit, means in said low voltage control circuit including solid state means effective to actuate said burner control means in response to a signal from said ignition detection means, electrical switch means controlled by said energy conversion means and effective to interrupt the flow of current through said main line source of AC current, and means interfacing between said low voltage control circuit and said burner control means, said interfacing means including a pair of resilient magnetic contact members disposed in normally spaced overlapping relationship and adapted to close and make electrical contact under the influence of magnetic flux, a pair of electrically insulated concentric coils having a differential in ampere turns and encompassing said contact members, the magnetic flux generated by said coils being additive whereby energization of both of said coils concurrently is effective to close said members and energization of one of said coils is sufficient to maintain said members closed, and a resistance wire of predetermined calibrated length electrically connected in parallel circuit between the ends of at least one of said coils.

Claim 8

In an electrical primary control system for furnaces, the combination including burner control means adapted to be connected to a furnace burner connected to a main line source of AC current, a low voltage control circuit including burner ignition detection means and energy conversion means, means providing a substantially lower voltage than line voltage in said control circuit, means in said low voltage control circuit including solid state means effective to actuate said burner control means in response to a signal from said ignition detection means, electrical switch means controlled by said energy conversion means and effective to interrupt the flow of current through said main line source of AC current, and means interfacing between said low voltage control circuit and said burner control means, said interfacing means including a pair of resilient magnetic contact members disposed in normally spaced overlapping relationship and adapted to close and make electrical contact under the influence of magnetic flux, a pair of electrically insulated concentric coils having a differential in ampere turns and encompassing said contact members, the magnetic flux generated by said coils being additive whereby energization of both of said coils concurrently is effective to close said members and energization of one of said coils is sufficient to maintain said members closed, and a resistance wire of predetermined calibrated length electrically connected in parallel circuit between the ends of at least one of said coils.

Claim 9

The combination as set forth in claim 6 wherein said resistance wire is comprised of nichrome.