Control apparatus

Claim 2

Control apparatus for a burner including: a flame detector; a flame relay including circuit means adapted to assume, responsive to flame, a state (designated a) when flame is absent and a state (designated b) when flame is present, said flame relay controlling switches adapted to actuate an ignition mode of said burner when said flame relay is in state a and an operate mode of said burner when said flame relay is in state b, a control relay including circuit means effecting admission of fuel to said burner when in an energized state (x) and withholding of fuel when in a passive state (y), an operating control switch for applying power to said control apparatus, a first timer including circuit means connected to assume an active state when either of the following conditions occurs: 1) said flame relay is in state a, said control relay is in state x, or 2) said flame relay is in state b, and said control relay is in state y, said first timer controlling circuits which lock out power to said control apparatus after said first timer a second timer including circuit means adapted to apply power to said first timer after a predetermined interval after power is applied to said apparatus, and clamping circuitry operating when said flame relay is in state b b and said control relay is in state y, to clamp said flame and control relays in states b and y respectively, overriding the influence of said flame detector.

Claim 3

The control apparatus of claim 1 in which said flame detector includes a flame rod.

Claim 4

The control apparatus of claim 1 in which said clamping circuitry includes a clamping switch controlled by said flame relay.

Claim 5

The control apparatus of claim 3 in which said flame relay is actuated by an amplifier, the input of which is operatively connected to said flaMe detector.

Claim 6

The control apparatus of claim 4 wherein said amplifier is connected by said clamping switch to a terminal grounded when said control relay is in state x.

Claim 7

The control apparatus of claim 5 wherein said terminal is so grounded by a switch controlled by said control relay.

Claim 8

The control apparatus of claim 1 in which said control relay includes rectifying elements adapting it to operate on alternating current.

Claim 9

Apparatus for controlling a burner including: a flame detector, a flame relay including circuit means and effecting in its normal state an ignition mode of said burner and in its energized state an operate mode of said burner, electronic circuitry including at least one amplifier and adapted to receive a signal from said flame detector and responsive to said flame detector to put said flame relay in an energized state, a control relay including circuit means for controlling the flow of fuel to said burner, a first time delay element including circuit means adapted to effect a shutdown of said burner whenever an ignition mode is prolonged beyond a predetermined interval, a second time delay element including circuit means adapted to provide a check period between a call for burner operation and the onset of fuel flow to said burner, a circuit loop including in serial order around said loop a normally closed control-relay-controlled switch, a normally open flame-relay-controlled switch, a normally closed flame-relay-controlled switch, and a normally open control-relay-controlled switch, said loop being grounded between said normally open control-relay-controlled switch and said normally closed control-relay-controlled switch and said loop being connected at a point between said normally open control-relay-controlled switch and said normally closed flame-relay-controlled switch to one side of said control relay, a circuit connection including a normally open flame-relay-controlled switch and a rectifier connecting said point between said normally open control-relay-controlled switch and said normally closed flame-relay-controlled switch to a control point of said amplifier whereby said flame relay is clamped in its energized state when a malfunction of said flame detector produces a spurious indication of flame during said check period.

Claim 10

Apparatus for controlling a burner including: a flame detector, a flame relay including circuit means and effecting in its normal state an ignition mode of said burner and in its energized state an operate mode of said burner, electronic circuitry including at least one amplifier and adapted to receive a signal from said flame detector and responsive to said flame detector to put said flame relay in an energized state, a control relay including circuit means for controlling the flow of fuel to said burner, a first time delay element including circuit means adapted to effect a shutdown of said burner whenever an ignition mode is prolonged beyond a predetermined interval, a second time delay element including circuit means adapted to provide a check period between a call for burner operation and the onset of fuel flow to said burner, a circuit loop including in serial order around said loop a normally closed control-relay-controlled switch, a normally open flame-relay-controlled switch, a normally closed flame-relay-controlled switch, and a normally open control-relay-controlled switch, said loop being grounded between said normally open control-relay-controlled switch and said normally closed control-relay-controlled switch and said loop being connected at a point between said normally open control-relay-controlled switch and said normally closed flame-relay-controlled switch to one side of said control relay, a circuit connection including a normally open flame-relay-controlled switch and a rectifier connecting said point between said normally open control-relay-controlled switch and said normally closed flame-relay-controlled switch to a control point of said amplifier whereby said flame relay is clamped in its energized state when a malfunction of said flame detector produces a spurious indication of flame during said check period.