The Locomotive Of Today

The Boiler: Bioivers, Capacity of the Boller. 33 through holes drilled in the pipe, or suspending any heavy piece of metal inside by means of hooks, and even by stretch- ing a piece of wire across the top of the pipe. Ihese practices are however to be condemned, as the liability of dropping obstacles down the pipe, and thus causing damage by getting into the moving parts, is very great. The blower is provided to create a draught by means of a steam jet, and assist the lire when raising steam, or when the engine is stationary, standing at stations, etc. It is usually made by* a ring formed rouncl the outlet of the biast pipe,, which has a series of holes in its upper surface, so that when steam is admitted it will escape through these holes, pass up the chimney and cause a draught. This ring may be either cast in one with the nozzle, and have suitable unions by which a pipe can be attached to it from the blower cock, as at A, or the blower may be entirely separate, of copper pipe, which is bent to a circular form as far as possible and laid on a ledge, or in some cases on lugs cast on the pipe for its reception, holes being drilled as in the last case at its upper face. G shows a plan and section of this form of blower. A second arrangement is to have a single pipe laid up alongside the biast pipe, discharging up the chimney, but this is not so good as the first. In some engines the steam used for exhausting the air from the vacuum brakes by the small ejector can be at will discharged through the blower, thus answering two purposes ; but in most cases it is “live” steam that is used, and then it is good practice to take it from the dorne by means of an internal pipe, so as to insure dry steam in all cases. The blower is entirely under the control of the men in charge of the engine. The internal capacity of the boiler may be said to be divided into two parts, the water space or portion below the water line, and the steam space or that above it, in which the steam generated is collected; authorities differ as to the exact proportion that these should bear to each other, but as a general rule the water space is about j of the total capacity of the boiler. A large body of water gives a steady supply of steam, and ampie steam space lessens the liability to “prime,” a trouble referred to later on. A usual method of increasing the steam space without carrying the water too low in the boiler, is by adding a dorne, also by making the firebox wrapper plate of a larger diameter than the barrel. This may be done in two ways, the plan usually adopted in this country, known as the raised firebox, has the throat plate extended over the top of the barrel 3