Abstract: Coal-fired power station with controller for air-fuel ratio in combustion of ground coal, with pneumatic conveying of ground coal to burners of power station. An electrode (10) with average radius rm with 0.1 mm?rm?1.2 mm arranged in channel carrying air in flow direction of air upstream of sensors (11) of correlation measurement device (12) at distance l with 1× unobstructed width of flow cross-section of the channel carrying the air<l<10× unobstructed width of the flow cross-section of the channel carrying the air in the region of the sensors (11). A counter electrode (13, 25) electrically operative relative to electrode (10) is arranged in upstream of sensors (11), and electrode (10) and counter electrode (13, 25) are connected with different poles of a high-voltage source (9) configured for providing a voltage U of 12 kV?U?20 kV.

Abstract: A device and method for controlling fuel-air ratio during combustion of ground in a coal power plant, including pneumatic delivery of ground coal to the burners and feeding combustion air to burners while controlling the combustion air and the amount of carrier air. A high reliability of control combined with low maintenance of the air mass measurement devices is achieved. This is achieved by a measurement device for measuring the amount of combustion air which, according to correlation measurement, evaluates the triboelectric effects on sensors. Between 0.1 mg and 10 mg of fine-grained particles of a diameter between 20 ?m and 200 ?m are introduced per m3 air into suctioned fresh air, which is carried out during the starting of the firing system. This is done by correlation measurement that evaluates triboelectric effects on sensors, arranged in series in carrier air stream in direction of flow of the carrier air.

Abstract: An apparatus and a method for producing samples of a finely granular and dry material for measuring the residual carbon content thereof. The material is fed by a torque monitored conveyor screw to a measuring chamber and is progressively compacted therein. At an abrupt increase in screw torque feeding of the material ceases yielding a sample in the measuring chamber of a reproducible degree of compaction.

Abstract: A method of determining the quantity of particulate matter suspended in a carrier gas in a pipe by measuring the frequency shift over a substantially linear range of an attenuation curve below the cut-off frequency for wave propagation, the curve being derived from measuring the attenuation of an electric field established in a conductive pipe substantially free of wave propagation.