Transfer of Heat

—In steam engineering, refers specially to the transmi ion of heat from a boiler furnace to the water within. Rapidity of circulation is nece ary to prevent destructive overheating of the plates, which would soon happen if the heat transferred from the furnace were not carried away rapidly by the water. The coating of deposits of the feed water and sooty accumulations interfere with the transmi ion of heat. Thin plates conduct more rapidly than thick ones, _ and the rate of transmi ion area is more efficient than tube area, because of the greater concentration of heat there. The rate of transmi ion signifies the number of heat units transferred per hour, but the amount of heating surface will vary in different types of boilers.