The Engineers' Manual of the Local Marine Board Examinations, for Certificates of Competency, as Second and First-Class Engineers
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1875 edition. Excerpt: ... the gross horse-power, as shown by the indicator, was almost identical in both cases, in the latter case the power exerted was obtained at an expenditure of 1472 cubic feet of atmospheric steam per minute, in place of 1o-87 cubic feet, as formerly; 3-85 cubic feet of steam per indicated horse-power per minute being thus saved by the principle of expansion. It is apparent that this calculation will not give us the cause of any loss of effect by the steam escaping, or being condensed in the pipes, etc., which must be sought for when suspected, either in the form of the indicator diagram, or by testing the engine for leakage of steam or air. Fig. 61. i _ On THE FORM OF THE DIAGRAM WHEN THE STEAM IS THROTTLED BY THE L1nk.--In fig. 61, we have diagrams taken from top and bottom of an engine, when Blowed to strokes per minute, which is effected by partly closing the throttle valve, and partly by shifting the link towards its midposition. It will be observed that in these diagrams nearly the whole areas are below the atmospheric line. Note also that on the left hand corner of one of the figures a loop is formed, which not unfrequently appears in engines employing the link, and the meaning of which we shall now proceed to explain. The extreme point of the diagram, in every instance, answers to the length of the stroke; and if the steam is pent up in the cylinder by the eduction passage being shut before the end of the stroke, or if it be permitted to enter before the end of the stroke, the pencil will be pushed up to its highest point before the stroke terminates, and since the paper still continues to move onward the upper part of the loop is formed. If the pressure within the cylinder, when the piston returns, were to be precisely the same as when the...
- Paperback | 98 pages
- 189 x 246 x 5mm | 191g
- 04 Jul 2012
- Miami Fl, United States
- Illustrations, black and white