The Steam Engine Explained and Illustrated (Seventh Edition) / With an Account of Its Invention and Progressive Improvement, and Its Application to Navigation and Railways; Including Also a Memoir of Watt

by Dionysius Lardner

(134.)

Figs. 49., 50.

Fig. 51.

In a slide constructed in this manner, the steam filling the space T H has a tendency to press the slide back, so as to break the contact of the rubbing surfaces, and thereby to cause the steam to leak from the space T H to the back of the slide. This is counteracted by the packing x, at the back of the slide.

In engines of very long stroke, the extent of the rubbing surfaces of slides of this kind renders it difficult to keep [Pg232] them in steam-tight contact and to insure their uniform wear. In such cases, therefore, separate slides, upon the same principle, are provided at the top and bottom of the cylinder, moved, however, by a single rod of communication.