Abstract: A fuel supply control system including a major area diaphragm and a minor area diaphragm defining therebetween a reference pressure chamber. A control pressure chamber is located adjacent the major area diaphragm on a side thereof opposite to the reference pressure chamber and a controlled pressure chamber is located adjacent the minor area diaphragm on a side thereof opposite to the reference pressure chamber. A valve is connected to the diaphragms for regulating the opening of an orifice of a fuel passage and the controlled pressure chamber serves as a chamber of the fuel passage. The control pressure chamber is connected to a combustion air supply passage system, and the reference pressure chamber is connected to a portion of an air supply and exhaust passage system, in which the pressure is lower than the pressure in the combustion air supply passage system.

Abstract: A burner system adapted to vaporize liquid fuel, generally kerosene, and burn gaseous fuel in blue flames includes an evaporator heated by a heater to about 250.degree.-300.degree. C. to vaporize the kerosene. The evaporator is thermally insulated from a premix passage and a burner, to reduce the time required for preheating the evaporator. At the time of ignition, the volume of a portion of primary air supplied to the evaporator is reduced below the corresponding volume supplied in maximum combustion condition and the volume of the kerosene supplied to the evaporator is substantially equal to the corresponding volume supplied in maximum combustion condition. This enables a premix of liquid and air within a combustible limit to be supplied to flame ports even if part of the premixture forms dew in the premix passage, and allows an enriched premixture to flow out of the flame ports at low velocity to facilitate ignition.

Abstract: A burner having main air ports for issuing a secondary air at a relatively high flow velocity, and auxiliary air ports for issuing a secondary air at a relatively low flow velocity located upstream of the main air ports with respect to a stream of a gaseous fuel or a preformed mixture of fuel and primary air in which the fuel is enriched over and above a flammability limit. The secondary air issuing from auxiliary air ports may have its flow velocity reduced by utilizing speed reducting compartments formed in a combustion chamber or recesses formed in walls of the combustion chamber. Flame stabilizing plates may be provided near the auxiliary air ports to extend substantially perpendicularly to the stream of the gaseous fuel or the preformed mixture of fuel and primary air.

Abstract: A gaseous fuel-air premix combustion burner is disclosed wherein the production of oxides of nitrogen can be inhibited. By blowing secondary air onto at least a maximum temperature region of a secondary reaction region of a gaseous fuel-air premix combustion flame, it is possible to minimize the production of oxides of nitrogen not only in regions of the flame where the volume of primary air is smaller or larger than the theoretical volume of air but also in the vicinity of a region of the theoretical volume of air, whereby the area of a region where the production of oxides of nitrogen is reduced can be increased.