Abstract: Three burners are supplied with pulverized fuel entrained in air from a splitter and are brought to combustion under optimum conditions by adjustment of the secondary air flow to each. The rates of flow of primary and secondary air are determined and signals from these, and a representation of the total fuel supply are supplied to a computer by which the amount of fuel flowing to each burner is deduced from the ratio of the air supplied to the burners.

Abstract: The invention is concerned to control the combustion conditions of a burner 1 supplied with a mixture of pulverized fuel and air. By use of a vortex amplifier 10 in the supply pipe 3, the supply of fuel is interrupted so that the flame is consequently first too lean and then too rich. The temperature of the burner flame is monitored by a photodiode device 6a and an indication is produced of the delay between the operation of the vortex amplifier 10 and the flame temperature passing through that indicating that the flame conditions are optimum. The length of the delay will indicate whether, and to what extent, the flame before the operation of the vortex amplifier was too lean or too rich. Adjacent burners can be controlled by operating the vortex amplifiers associated with each at different regular frequencies.