Control of burners

Claim 2

Control means for the reactant flow ratio for at least one burner comprising at least one valve for controlling the general level of flow of a reactant to the burner, a variator for applying to the flow periodic fluctuations of small amplitude and low frequency as compared with the natural frequency of flame flicker, a detector for radiation from the flame from the burner and for emitting a signal corresponding to the radiation, phasesensitive detector means for assessing the polarity of any correlation between the applied fluctuations and the signal from the radiation detector, and an adjuster responsive to the polarity of the correlation assessed by the phase-sensitive detector means for adjusting the reactant flow ratio at the burner.

Claim 3

Burner control means as in claim 1 wherein the valve is provided with an electrical actuator connected to the valve member for setting the general level of flow, and the variator is an electrical oscillator the input frequency of which is compared with the frequency of the detected signal.

Claim 4

Burner control means as in claim 1 wherein the valve is provided with a mechanical actuator connected to the valve member for setting the general level of flow, and the variator is a corresponding vibrator, a transducer being provided to produce from the vibrator an input signal for the phase-sensitive detector means to correlate with the output signal from the radiation detector.

Claim 5

Burner control means as in claim 1 wherein the variator is the valve member controlling the flow to which fluctuations are to be applied, the valve member having a natural frequency under conditions of gas flow, and a transducer is provided to produce from the valve member an input signal for the phase-sensitive detector means comparator to correlate with the output signal from the radiation detector.

Claim 6

Burner control means as in claim 1 wherein the valve is provided with an actuator for setting the position of its valve member.

Claim 7

Burner control means as in claim 5, wherein the actuator of the valve also serves as the adjuster.

Claim 8

Burner control means as in claim 1 for an installation utilizing a number of burners, wherein individual valves are provided for controlling the general level of flow of reactant to the burners, individual variators are provided for applying fluctuations to the valve members of the different valves, and individual adjusters are provided for adjustment of the reactant flow rates at the different burners, sufficient differences being provided between the fluctuations applied to each to enable the phase-sensitive detector means to differentiate between the fluctuations of the radiation from the flames from the different burners, for the adjuster of the appropriate burner to be operative, and individual radiation detectors are provided for the different burners.

Claim 9

Burner control means as in claim 1 for an installation utilizing a number of burners, wherein individual valves are provided for controlling the general level of flow of reactant to the burners, individual variators are provided for applying fluctuations to the valve memberS of the different valves, and individual adjusters are provided for adjustment of the reactant flow rates at the different burners, sufficient differences being provided between the fluctuations applied to each to enable the phase-sensitive detector means to differentiate between the fluctuations of the radiation from the flames from the different burners, for the adjuster of the appropriate burner to be operative, and a single radiation detector serves for all the burners, and means for switching the phase-sensitive detector means to be sequentially responsive to the single radiation detector to examine and adjust the flame from each burner.

Claim 10

Burner control means as in claim 1 for an installation utilizing a number of burners, wherein individual valves are provided for controlling the general level of flow of reactant to the burners, individual variators are provided for applying fluctuations to the valve members of the different vales, and individual adjusters are provided for adjustment of the reactant flow rates at the different burners, and a single radiation detector servies for all the burners by applying the fluctuations to one burner at a time, and means for switching the appropriate adjuster to the phase-sensitive detector means.