A notable feature of modern boiler construction is the mode of building the apparatus of cast iron in either horizontal or vertical sections.
A boiler with horizontal sections is shown in fig.
Graduates of technical schools are received as special apprentices and are directed in a course of four years through the erecting shops, vice shop, blacksmith shop, boiler shop, roundhouse, test department, machine shop, air-brake shop, iron foundry, car shop, work of firing on the road, office work in the motive power accounting department, and drawing room; the most competent may be admitted through the grades of inspector, in the office of the master mechanic or of the road foreman of engines, assistant master mechanic, assistant engineer of motive power, master mechanic and superintendent of motive power.
In the low pressure two pipe system the flow pipe is carried to a sufficient height directly above the boiler to allow of its gradual fall to a little beyond the most distant point at which connexion is to be made with the return pipe, which thence slopes towards the boiler.
This steam condensing adds to the water in the pipe and naturally causes an overflow, which is led back to the boiler and re-used.
The first group consists of experiments selected from the records of a large number made on the boiler of the locomotive belonging to the Purdue University, Indiana, U.S.A.
There are great iron and steel works, producing every kind of heavy goods used by railway and engineering works, such as boiler plates, rails, axles, tubes, bolts and nuts.
The boiler is heated by a furnace, and the oil is brought gradually to the point of ebullition, at which it is maintained for two hours, during which time moisture is driven off, and the scum and froth which accumulate on the surface are ladled out.
The first one of the group was made on the boiler fixed in the locomotive yard at Stratford, and the two remaining experiments of the group were made while the engine was working a train between London and March.
For large buildings where large quantities of hot water are used an independent boiler of suitable size should be installed.