Primary control means for furnaces

Claim 2

In a primary control 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 a flame detector, means providing a substantially lower voltage then 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 flame detector, thermal delay lockout electrical switch means effective to interrupt the flow of current through said solid-state means, and means including a reed switch for interfacing between said low voltage control circuit and said burner control means.

Claim 3

The combination as set forth in claim 1 wherein said burner control means includes a triac.

Claim 4

The combination as set forth in claim 1 wherein said solid-state means includes a silicon controlled rectifier having an anode, a cathode and a gate.

Claim 5

The combination as set forth in claim 1, said low voltage control circuit including a pair of electrically insulated coils having a differential in ampere turns and the magnetic fluxes of which are additive whereby energization of both of said coils effects closing of said reed switch contacts and continued energizations of one of said coils maintains said reed switch contacts in a closed condition.

Claim 6

The combination as set forth in claim 4, wherein said low voltage control circuit includes a DC supply for one of said coils.

Claim 7

The combination as set forth in claim 5, wherein said solid-state means and said safety switch control the flow of current through the other of said coils.

Claim 8

The combination as set forth in claim 3 wherein said flame detector is in the form of a cadmium sulfide flame detector, said detector controlling the flow of current to the gate of said silicon controlled rectifier.

Claim 9

The combination as set forth in claim 2 wherein said interfacing means controls the energization of said triac.

Claim 10

In a primary control 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 a flame detector, a silicon controlled rectifier, a thermostat, and a bimetallic switch, means providing a substantially lower voltage than line voltage in said control circuit, and means for interfacing between said burner control means and said low voltage control circuit, said interfacing means including a normally open reed switch.

Claim 11

In a primary control 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 a flame detector, a silicon controlled rectifier, a thermostat, and a bimetallic switch, means providing a substantially lower voltage than line voltage in said control circuit, and means for interfacing between said burner control means and said low voltage control circuit, said interfacing means including a normally open reed switch.

Claim 12

The combination as set forth in claim 9 wherein said burner control means includes a triac having a gate.

Claim 13

The combination as set forth in claim 9 wherein said silicon controlled rectifier includes an anode, a cathode and a gate.

Claim 14

The combination as set forth in claim 9 wherein said low voltage control circuit includes a pair of electrically insulated coils having a differential in ampere turns and the magnetic fluxes of which are additive whereby energization of both of said coils effects closing of said reed switch and energization of one of said coils maintains said reed switch in a closed condition.

Claim 15

The combination as set forth in claim 12 wherein said low voltage control circuit includes a DC supply for one of said coils.

Claim 16

The combination as set forth in claim 13 wherein said silicon controlled rectifier and said bimetallic switch control the flow of current through the other of said coils.

Claim 17

The combination as set forth in claim 11 wherein said flame detector controls the flow of current to said gate of said rectifier.

Claim 18

The combination as set forth in claim 10 wherein said reed switch controls the flow of current to go to said gate of said triac.

Claim 19

The combination as set forth in claim 9, said bimetallic switch 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 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, means effective to heat said first blade and disengage said stop means from said one contact member, and manually operable means effective to move said one contact member into engagement with said stop means.

Claim 20

The combination as set forth in claim 17 wherein said manually operable means is in the form of a plunger, said plunger sequentially engaging said contact members upon the application of manual force thereto and maintaining separation of said contact members until said one contact member engages said stop means.

Claim 21

The combination as set forth in claim 18, said mounting base including a web portion and a pair of spaced flange portions, said first blade being carried by one of said flange portions in spaced relationship with respect to said web portion.

Claim 22

The combination as set forth in claim 19 wherein said manually operable means includes resilient means biasing said manually operable means away from said one contact member.