Primary control means 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, energy conversion means effective to interrupt the flow of current through said solid state means, said energy conversion means including a mounting base, first and second bimetallic blades, one end portion of said first blade being fixed to said base, the other end portion of said first blade being fixed directly to one end portion of said second blade, said first and second blades bending in opposite directions upon an increase in temperature, stop means carried by the other end portion of said second blade, a pair of contact members fixed to said base, said contact members being in electrical contact with each other when one of said members is in engagement with said stop means, electrical heating means encompassing said first blade and effective to heat said first blade to cause said stop means to be disengaged from said one contact member responsive to bending of said first blade, the directions of bending of said first and second blades responsive to change in temperature being such that an increase in temperature of said second blade will tend to counteract deflection of said stop means responsive to an equivalent increase in temperature of said first blade, manually operable means supported by said base and effective to move said contact member into engagement with said stop means, and means interfacing between said low voltage control circuit and said burner control means.

Claim 3

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, 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 effective to interrupt the flow of current through said solid state means, said electrical switch means including a hoursing having an end wall, a U-shaped mounting base having a web portion and a pair of spaced flange portions disposed in said housing, first and second bimetallic blades, one end portion of said first blade fixed to one of said flange portions, the other end portion of said first blade being fixed directly to one end portion of said second blade, said first and second blades bending in opposite directions upon an increase in temperature, stop means carried by the other end portion of said second blade, a pair of resilient contact members fixed to said web portion of said base, said contact members being in electrical contact with each other when one of said members is in engagement with said stop means, electrical heating means encompassing said first blade and being effective to heat said first blade to cause said stop means to be disengaged from said one contact member responsive to bending of said first blade, the directions of bending of said first and second blades responsive to a change in temperature being such that an increase in temperature of said second blade will tend to counteract deflection of said stop means responsive to an equivalent increase in temperature of said first blade, a manually operable plunger, said plunger being supported for axial movement by the other of said flange portions and said end wall of said housing, said plunger sequentially engaging said contact members upon the application of manual force thereto and maintaining separation of said members until said one contact member engages said stop means, resilient means biasing said plunger away from said one contact member and toward said end wall, and means interfacing between said low voltage control circuit and said burner control means.

Claim 4

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, 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 effective to interrupt the flow of current through said solid state means, said electrical switch means including a hoursing having an end wall, a U-shaped mounting base having a web portion and a pair of spaced flange portions disposed in said housing, first and second bimetallic blades, one end portion of said first blade fixed to one of said flange portions, the other end portion of said first blade being fixed directly to one end portion of said second blade, said first and second blades bending in opposite directions upon an increase in temperature, stop means carried by the other end portion of said second blade, a pair of resilient contact members fixed to said web portion of said base, said contact members being in electrical contact with each other when one of said members is in engagement with said stop means, electrical heating means encompassing said first blade and being effective to heat said first blade to cause said stop means to be disengaged from said one contact member responsive to bending of said first blade, the directions of bending of said first and second blades responsive to a change in temperature being such that an increase in temperature of said second blade will tend to counteract deflection of said stop means responsive to an equivalent increase in temperature of said first blade, a manually operable plunger, said plunger being supported for axial movement by the other of said flange portions and said end wall of said housing, said plunger sequentially engaging said contact members upon the application of manual force thereto and maintaining separation of said members until said one contact member engages said stop means, resilient means biasing said plunger away from said one contact member and toward said end wall, and means interfacing between said low voltage control circuit and said burner control means.

Claim 5

In an electrical primary control system for furnaces, the combination including a burner control triac 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 triac in response to a signal from said ignition detection means, energy conversion means including a switch means effective to interrupt the flow of current through said solid state means, and means interfacing between said low voltage control circuit and said burner control triac.

Claim 6

In an electrical primary control system for furnaces, the combination including a burner control triac 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 triac in response to a signal from said ignition detection means, energy conversion means including a switch means effective to interrupt the flow of current through said solid state means, and means interfacing between said low voltage control circuit and said burner control triac.

Claim 7

The combination as set forth in claim 3 wherein said switch means includes time delay means.

Claim 8

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

Claim 9

The combination as set forth in claim 3 wherein said interfacing means controls the conduction of said burner control triac.

Claim 10

In an electrical primary control system for furnaces, the combination including a burner control triac, said triac including one main terminal adapted to be connected to a furnace burner, said triac including another main terminal adapted to be connected to a main line source of AC current, said triac also including a gate for rendering said triac conductive across said main terminals when said gate is energized, 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 energize said gate of said burner control triac 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 solid state means, and means interfacing between said low voltage control circuit and said gate of said burner control triac.

Claim 11

In an electrical primary control system for furnaces, the combination including a burner control triac, said triac including one main terminal adapted to be connected to a furnace burner, said triac including another main terminal adapted to be connected to a main line source of AC current, said triac also including a gate for rendering said triac conductive across said main terminals when said gate is energized, 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 energize said gate of said burner control triac 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 solid state means, and means interfacing between said low voltage control circuit and said gate of said burner control triac.