The Works Of Messrs. Schneider And Co.

no MESSRS. SCHNEIDER AND CO.’S WORKS. positions of the cranks, and for executing accurately ail the manœuvres. The degree of expansion is increased as soon as the engihes are started. In order to secure this, the driver brings the reversing gear lever into an Intermediate position, and he complétés the travel of the lever when the cable has run out or in. Owing to this arrangement, the drivers have no special attention to give to regulating the expansion; they have only to (livide the travel of the reversing gear lever into two periods. The servo-motor is provided with an oil brake, com- munication from one end of the brake to the other being regulated by a small slide valve of special design, governed by the checking mechanism of the servo-motor. By this slide valve all communication between the two ends of the brake can be stopped, and consequently the servo-motor piston and the links of the distribution mechanism can be maintained, when the engine is working, in all intermediate positions. The arrangement does away with all jerks and reactions on the drivers arms, and provides for working with expansion, as mentioned above. The servo-motor is placed vertically below the floor level of the engine, and is supportée! by two cast - iron columns, which carry the re verging, shaft plumber-blocks. The motor shaft is fitted with the brake pulley, and the two winding drums, one fixed and the other that can be made loose to regulate the leneth of cable. The arms of the drums are of cast iron, and they are counterweighted. The inside of the arms is lined with wood, in order to prevent the wearing of the cables. The brake is provided with double Blocks, and is arranged so as to be set under the action of a heavy counterweight. When the engines are working, the bi-ake is taken off by steam power, which, by acting under a piston, lifts the counterweight. The piston and counterweight fitted on the same rod, act direct on the brake lever. This type of brake is found préférable to those for the setting of which steam power is used, and is mueh more reliable, as the accidents that would arise owing to a fracture of the steam pipe, or through prématuré closing of the automatic boiler valves, are entirely done away with. In order to prevent shocks, special means are provided to regulate the escape of the steam. All the pieces forming the brake, the pulley excepted, are of forged steel, of ample dimensions for the strains they have to withstand. The automatic setting of the brake, and the stoppage of the engines when the hauling-eage rises too high, are obtained by means of special devices. Strong hollow frames, secured to the foundations, carry the crankshaft plumber-blocks, the slides, and the steam cylinders. This type of frames was deemed by Messrs. Schneider and Co. préférable for these engines to the closed-in types, as the regulating of the slides and pistons after wear is more easily effeeteel ; the arrangement also gives facility for levelling of the engines when the founda- tions get distorted, which is often the case in the close vicinity of mines. Another great advantage is that the connecting-rods are well in sight of the driver ; more- over, this type of frames enables the two engines to be firmly secured together by means of strong cross-frames, which maintain the crankshaft plumber-blocks in position, and thus prevent all strains on the crankshafts and the heating of the brasses. In the Beaubrun engines there are three such cross-frames. It is claimed that these engines, in eombining simplicity of mechanism with strength and economical working, form the best type of hauling engines. The requirements of the service are fully met, and the facility with which they are kept in order is insured, and these conditions have not been sacrificed to other, and often doubtful advantages. High-Speed Engines.—The improvements ntroduced man y years ago by Mr. G. H. Corliss in. the construction of steam engines, caused considérable progress to be realised as regards réduction in steam expenditure and the regularity of working. The principal engineers all over the world worked under the Corliss patents, or adopted modifications of them, and the use of the Corliss engine type has become general in the most varied industries. These engines, however, notwithstanding their advantages cannot always be used for driving dynamos ; theii mechanical devices do not allow of their working at a sufficiently high speed, and the necessity that exista in many cases of doing away with intermediate transmissions between the engines and dynamos, and the small space available, combined with the considération of first cost of a plant, have led to the designing of high-speed steam engines. Messrs. Schneider and Co., who commenced electrical work on a large scale several years ago, manufacture a type of high-speed engine, the general features of which differ materially from those of other makers. A model of this engine was exhibited at Chicago in 1893 and at Lyons in 1894. Economical working was a considération generally neglected when high-speed engines were first introduced, but this did not long remain the case. Owing to the arrangements they have adopted, Messrs. Schneider and Co. have produced a motor that works economically, without sacrificing anything to simplicity of construction, an important item in engines of this kind. Their aim was to keep as near as possible to the steam consumption of the Corliss engine, and they did not have recourse, to obtain this, to a succession of expansions in several steam cylinders, but provided the single cylinder of their engine with a system of distribution as perfect as possible, thus producing a very simple motor of high mechanical efficiency. Comparative trials, carefully carried out, have shown the consumption of steam in these engines to be below that of most of the high-speed compound engines used in electric lighting installations. The steam inlet and outlet valves are worked independently one of the other ; the dead spaces are very small, owing to the use of separated slide valves acting on both ends of the cylinder ; the cylinder is perfeetly drained, as the outlet valves are ai the bottom ; and the quick opening of ail the steam ports is obtained by the arrangements chosen for working the slide valves.