Working Models for Engineering Students Engine Slide-Valves

Abstract

To obtain a thorough insight into the movements of slide-valves, and to completely understand the distribution of steam, is generally a difficult matter to first-year students and engineering apprentices. These models, however, should greatly assist all who study the subject; they are neatly printed on cardboard, the important parts are sectioned and tinted, and the valves are movable so-as to show their positions when the piston is at any part of the stroke. The relative positions of crank-pins and eccentrics are clearly shown, as well as the valves and steam-ports. The models are of a convenient size, being six inches long by four inches wide, and they represent eight different kinds of slide-valves. As such models must be absolutely accurate from a mechanical point of view to be of use to technical students, we must point out that No. 1 is said to represent a slide-valve common in locomotive practice; but the valve spindle is shown passing through the valve, whereas valve buckles are always used. No. 2 is a single-acting piston valve for a steam hammer. If it is considered necessary in this case to show the piston and rod, why not do it accurately? The parts shown do not represent a steam-hammer piston and part of the rod.