Abstract: A pulverized coal combustion apparatus comprises a burner through which pulverized coal and carrier air are passed to be burnt in a combustion chamber, and a flame retainer disposed at an end of the burner. The flame retainer includes a flared tube and an annular plate, which plate has a plurality of radially inwardly projecting parts equiangularly spaced from each other. The annular plate comprises a plurality of ceramic pieces and a plurality of fastener elements, both of which are arranged and assembled alternately to form the annular plate. Each ceramic piece is so shaped that it projects radially inwardly to serve as the projecting part when assembled. The ceramic piece has at opposite sides thereof smoothly curved edge surfaces, and the fastener element has at opposite sides thereof smoothly curved edge surfaces which are engaged with the curved edge surfaces of neighboring two ceramic pieces.

Abstract: A combustion apparatus for low concentration NOx for burning gas, oil and coal along the same axis, having overcome the drawbacks of the prior art, without hindering the whirling of the air and also having prevented clogging of the nozzle and combustion vibration is provided, which apparatus is provided with a means for carrying pulverized coal by a primary air, a means for feeding a gas fuel through a gas nozzle, a means for separating combustion air into a secondary air and a tertiary air and feeding these airs, and a means for feeding and spraying an oil, and which apparatus is characterized by providing an annular space part between the flow paths of the secondary air and the tertiary air; and also arranging the gas nozzle penetrating through the annular space part in a movable manner in the axial direction.

Abstract: A method of combusting a coal-water mixture fuel. The mixture is atomized into a conically-shaped primary pre-combustion chamber. Primary air is supplied, at a rate smaller than that required for complete burning of the mixture and in the form of a swirl about the axis of the jet of the atomized mixture, from the peripheral portion of the primary pre-combustion chamber into a secondary pre-combustion chamber connected to said primary pre-combustion chamber, thus forming a region of low pressure around the jet of the mixture. The region of low pressure serves to induce the atmosphere gas from the secondary pre-combustion chamber of higher temperature back into the primary pre-combustion chamber of a lower temperature, so that the water content of the mixture is evaporated and the mixture is ignited by the heat of the hot atmosphere gas.

Abstract: A coal combustion apparatus capable of improving NO.sub.x reduction to a large extent is provided, which apparatus comprises a pulverized coal-feeding pipe (abbreviated to coal pipe) inserted into a burner throat on the lateral wall of a combustion furnace and for feeding the coal and air into the furnace; a means for feeding the coal and air into the coal pipe; a secondary air passageway formed between the coal pipe and a secondary air-feeding pipe provided on the outer peripheral side of the coal pipe; a ternary air passageway formed on the outer peripheral side of the secondary air-feeding pipe; a means for feeding air or an oxygen-containing gas into the secondary air passageway and that into the ternary air passageway; and a bluff body having a cross-section of a L-letter form provided at the tip end of the coal pipe.

Abstract: There are the primary fuel nozzle for jetting the first coal in the fine powder form with an air ratio up to 1, and the secondary fuel nozzle for jetting the second coal in the fine powder form with an air ratio at least 1 from the outer circumferential portion of the primary fuel nozzle. Swirl means are located at the top of the secondary fuel nozzle for swirling the second coal.

Abstract: Disclosed is a method of operating an air conditioner having a plurality of indoor units connected to a common outdoor unit as heat source machine. When operation of a plurality of indoor units is dictated depending upon the temperature differences between the room temperatures and the set temperatures therefor, the indoor unit having the smallest temperature difference is determined among those indoor units which are to operate, and the amount of heat exchange is limited in the indoor unit having the smallest temperature difference to advantageously perform air conditioning in respective rooms in which the indoor units are provided.

Abstract: A fan having forward-curved blades, such as a sirrocco fan or cross-flow fan, wherein the width of the outlet of an air passage between the adjacent two blades is 0.28 to 0.52 of the pitch of the blades at the inlet of the air passage, and the width of the inlet of the air passage is 0.85 to 1.2 of the width of the outlet thereof. The fan having blades of this construction has improved efficiency and reduced aerodynamic noise level in operation.