Page:Encyclopædia Britannica, Ninth Edition, v. 12.djvu/241

229 HEATING.] HORTICULTURE these, with a terminal water-way, is shown in elevation at fig. 33, and in section, showing the mode of setting, at fig. 34. The fire is made under the principal arch a ; the flame and smoke return through the flue b, and then turn back over the top of the boiler d 229 1 Saddle Boiler. to the outlet c, which can be placed at whatever point is in each case most convenient. The other parts referred to are d flow pipe, e return pipes, t soot-door for cleaning flues, g furnace door, h ash-pit door. FIG. 34. Fined Saddle Boiler (section). The Gold MeAal Boiler (figs. 35-38) is perhaps one of the best of these modified saddles, and like the others has a dome or arch a, and back water-way b ; the heated products of combustion striking against this back are sent up the central flue c, and then diverted ni to the side flues d, d, before passing into the chimney shaft e. Fig. 36 shows a transverse section, and fig. 37 a longitudinal section set in brickwork, which is shown in elevation in fig. 38. Gold Medal Boiler. The ash-pit is shown at/, the furnace door at h, the centre and side flues at c and d, the water-way end at b, the soot-door at i, the sludge-plugs for cleaning out the interior at g, the flow pipe at m, the return at n, while I shows a hollow space around the boiler for utilizing the heat given off by its exterior surface. This boiler is named from its having won the gold medal in a boiler competition at Birmingham in 172. The Witley Court boiler and the Glasgow boiler are both excellent forms of the flued saddle type. Stevens* Trentham Boiler (fig. 39) is a very powerful and Trent- economical one, for large establishments especially. It is a modifi- ham cation of the well-known Cornish boiler, and consists of two boiler, wrouglit-iron cylinders substantially rivetted together, and having FIG. 36. Gold Medal Boiler (transverse section), a water space of about 2 inches between them. The frame for the furnace doors d is attached to the front. It is supported by two cast-iron chairs a, a, the front chair forming the frame for the lower flue doors b, which fasten by a simple catch, and can readily James500 (talk) ~ 3H a I FIG. 37. Gold Medal Boiler (longitudinal section;. be lifted off for cleaning the flues. The plug c, opened by unscrew ing it, is for the purpo.se of clearing out all interior accumulations of dirt, which should be done thoroughly at short intervals. The flow pipe is at e, the return at/. In setting, the chairs are placed J- JG. ;j6. Gold Medal Boiler (brickwork setting). level on a solid foundation, and two 9-inch walls are built up so as just to clear the boiler, and about level with the centre of tho cylinder ; on these a co irse of fire-brick lumps is laid, and brought close up to the side of the cylinder, and resting on tho lumps an