Tub′u-lous Boil′er.
（Steam.) A form of boiler in which the water is carried in tubes or water-pipes, as distinguished from the flue-pipes, through which flame passes, as in the flueboil-ers of locomotives and elsewhere. A tubular boiler. Fig. 6757 shows Mast's tubulous boiler, the name being a sort of protest against the confounding of watertubes with flue-pipes. Each section is composed of two front manifolds d e (Fig. 6758) and one rear one, connected together by the upper and lower sets of tubes; these tubes being fitted to their places by right and left hand threads. These sections are united to each other by nipples k at the top and bottom of front manifolds, and the combination is completed by connecting the sets of sections to each side of a central column j p, to the top of which is attached the steam dome o. Extending outside of the masonry from [2650] the upper and lower sections are two pipes l connecting to a vertical stand-pipe f, containing the automatic water-regulator. From the lower end of this stand-pipe extends another pipe to the mud-drum m, while from the top a pipe g connects to the feed-tank. The tubes are lap-welded, of wrought-iron. b is the gage-glass.
