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INTRODUCTION

ENGINEERING DIVISION

in the following pages the author proposes to deal mainly with the operation of steam engines, boilers, feed pumps, and all the necessary adjuncts of a steam piant, rather than with the construction and erection of the same, although the designing and construction of steam machinery will receive some attention.

In order to successfully operate a steam plant the engineer in charge should, in addition to his other accomplishments, have at least sufficient technical knowledge to enable him to ascertain, by measurements and calculations, such very important points as the safe working pressure of his boiler, the most economical point of cut off for his engine, whether engine and boiler are properly proportioned for the work to be performed, and many other details which will be treated upon in their proper place.

Without a doubt the most successful operating engineers are those who combine practice with theory, and in order to obtain a practical working knowledge of steam engineering it is absolutely necessary that the young man who desires to become a successful engineer should start in the boiler-room, that he should thoroughly familiarize himself with all of the details of boiler management, and while his hands and eyes are thus gradually being trained to the practical part of the work he should at the same time be training his mind in the theoretical part by reading and studying technical books and journals relative to steam engineering. In order to facilitate this work

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series of practical questions will follow the close of each chapter, the answers to which may be found in the matter contained in the chapter. And now with the hope that a study of the following pages may prove to be a help to all into whose hands this book may come, the author respectfully dedicates it to his fcilow crartsmen, the engineers of America.

C. F. S.

Engineering

CHAPTER 1,

THE BOILER

Description of various types-Construction-Rules for ascertain

ing strength of sheet before and after punching-Strength of rivets—Single and double riveted seams—Triple riveted butt joints, strength of—Force tending to rupture a boiler-Rules for finding the safe working pressure of boilers--BracingRules for bracing-Bracing domes. It is hardly within the scope of this book to describe the many and varied types of metallic vessels known as steam boilers in use to-day for the generation of steam for power and other purposes. The author will deal mainly with those types most commonly used in this country for stationary service.

Description. These may be divided into four different classes. The first and most simple type, and the one from which the others have gradually evolved, is the plain cylinder boiler in which the heated gases merely pass under the boiler, coming in contact only with the lower half of the shell and then pass to the stack. These boilers are generally of small diameter (about 30 in.) and great length (30 ft.). Next comes the Aue cylindrical boiler, which is somewhat larger in diameter than the former, generally 40 in. diameter and 20 to 30 ft. long, with two large flues 12 to 14 in. diameter extending through it. The return tubular boiler, consisting of a shell with tubes of small diam

eter (249-4 in.) extending from head to head through which the hot gases from the furnace pass on their way to the stack. This boiler, which comes in the third class, is probably more extensively used in the United States for stationary service than any other type. The fourth class comprises the water tube boilers, in which the water is carried in tubes 3 to 4 in. in rameter, sometimes vertical and sometimes inclined, and connected at the top to one end of a steam drum,

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STANDARD HORIZONTAL BOILER WITH FULL-ARCH FRONT SETTING.

and having the lower ends of the tubes connected to a mud drum, which is also connected to the opposite end of the steam drum, thus providing for a free circulation of the water. Of the latter type there have been many different kinds evolved during the last one hundred years, the majority of them having had but a brief existence, being compelled to obey the inexorable law of the survival of the fittest, and to-day there are a few excellent types of water tube boilers

which have become standard and are being extensively used. The margin of safety as regards disastrous

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explosions appears to be in favor of the water tube boiler. It is not contended that they are entirely

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