Babcock & wilcox water tube boiler

               

A water tube boiler consisting in its simplest form of a horizontal drum from which is suspended a pair of headers carrying between them an inclined bank of straight tubes.

In marine boilers of this type are the water-tubes lying, but slightly inclining towards the boiler front. The tube ends are connected to a number of vertically collecting boxes with almost quadratic cross section. These are made of sheet metal and are laterally wave shaped. The tubes can be cleaned or replaced through hand-holes that are place ahead of each tube. The collecting boxes, on the boilers front side, are in the down-end connected to a mud disposal box with a blow down valve. The upper end of the collecting boxes by means of elbowed pipes connected to the lying steam drum. The collecting boxes at the water tubes rear side are closed at both ends. From the upper ends are tubes connected to the steam drum above the water level. At normal conditions the water level will be little below the mid-point of the steam drum.