Abstract: A combustion technique and control is provided by the use of an optical pyrometer by means of which combustion control is afforded in accordance with the inspection of the combustion flame. The preferred optical pyrometer takes the form of an optical pyrometer having a single measurement cell which is alternately exposed to the flame through different filters arranged on a rotating disc driven by a motor. The circuit associated with the optical pyrometer, for purposes of generating control signals, features the use of a synchronous D. C. restorer which establishes a reference level for minimum signal distortion. Also employed is an AGC circuit by means of which one of the signals derived from one of the aforementioned filters is utilized to minimize undesired variations in the results. Gating logic is used to separate the two channels derived from the different filters and actually demultiplexes the two separate channels.

Abstract: A combustion control system is operated based on the detection of smoke density. A photoelectric device measures the intensity of light directed through the smoke by a lamp in order to measure the smoke density. This measurement is employed to control fuel and/or air supply or the like. To provide a standard reference, light is directed from the lamp through an alternate path not affected by the smoke to the photoelectric device. A shutter mechanism alternately exposes the photoelectric device to light passing through or circumventing the smoke. The photoelectric measurement is compared with a standard and the comparison is used to adjust circuitry connected to the photoelectric device to stabilize the effects of the latter. A continuous monitoring of the adjustment is carried out to determine when an acceptable range of adjustment has been exceeded. A smoke density amplifier is employed to increase effectiveness.

Abstract: Combustion control is effected by the use of a smoke detector and by solid state devices for the detection and amplification of electrical signals produced by a photoelectric cell for the purpose of controlling a motor which in turn adjusts fuel and air supplies. The electrical circuits include triac switches effective for running a servo-mechanism or motor in one direction or the other according to the density of the smoke in a flue venting combustion products from a combustion chamber. Light emitting diodes may be connected to op-amps for purposes of indicating the type of control being effected. A smoke accumulating means is employed for amplifying the products of combustion to facilitate the detecting and measuring of the same.