Complete examination questions and answers for marine and stationary engineers; a complete engine operator's catechism ...

Front matter

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Introduction

The development of the science of steam engineering and the continually increasing demand for more power for manufacturing purposes and for transportation, both on land and sea, have in these modern times resulted in the creation of power plants, which are truly marvelous in their details when compared with the steam machinery of forty years ago. Even the last twenty years have witnessed tremendous developments along these lines, and we may imagine the effect it would have upon an engineer, who twenty years ago was counted as first class in his business, but who, having taken a Rip Van Winkle sleep of twenty years, is suddenly awakened and finds hin> self set down in the engine room of a first-class ocean steamer, or in the midst of one of our modern up-to-date power plants. The facts are, he would have hard work td -redognize his surroundings. Even the steam gauges would indicate a pressure of 150 to 175 pounds more per square inch than did the old-time gauges. Therefore, in view of the remarkable improvements in steam machinery • which., have been made and are continually being made, it certainly behooves engineers to do their utmost to keep step with the march of progress. The author has endeav¬ ored, in the following pages, to place before his readers information in a catechetical form which will be found to cover all of the various details appertaining to the opera¬ tion of modern steam plants, both stationary and marine.

C. F. S.

CHAPTER I Ques. 1.—What is steam?

Ans.—Steam is vapor of water.

Ques. 2.—At what temperature will water evaporate (boil) in the open air at sea level?

Ans.—212 degrees Fahrenheit.

Ques. 3.—If 1 cubic foot of water is evaporated at 212 degrees into steam at atmospheric pressure, how many cubic feet of steam will there be? In other words, what will the volume of the steam be?

Ans.—1,646 cubic feet.

Ques. 4.—Then what is the relative volume of steam at atmospheric pressure, and the water from which it was evaporated at 212 degrees?

Ques. 5.—What is the relative volume of steam at 200 pounds gauge pressure, and the water from which it was generated?

Ques. 6.—What is meant by the terms atmospheric pressure, gauge pressure, and absolute pressure, as applied to steam and other gases?

Ans.—The pressure in pounds exerted by the steam, or gas, on each square inch of the interior surface of the containing vessel, tending to rupture it.

Ques. 7.—What is vacuum?

Ans.—The absence of all pressure in the interior of a vessel.

Table 1, which follows, shows the physical properties of saturated steam from a perfect vacuum up to 1,000 pounds absolute pressure. It will be found convenient for reference.

TABLE I

Properties of Saturated Steam

Vacuum

Inches of Mercury

Absolute

Pressure

Lbs. per Sq. Inch

Temp.

Degrees F.

H-h

1 Lb. Wt. of Steam

Wt. of t Cubic Foot of Steam, Lbs.

In the Steam

H

29-74

.089

O.

1091.7

3333-3

.0003

29.67

.122

1094.1

1086.1

154,330

2472.2

.0004

29.56

.176

1079.2

107,630

1724.1

.0006

29.40

.254

28.01

IIOO. 2

1072.2

76,370

1223.4

.0008

29.19

•359

38.02

1103.3

1065.3

54,660

875.61

.OOII

28.90

.502

48.04

1106.3

1058.3

39,690

635.80

.0016

28.51

.692

go.

58.06

1109.4

1051.3

29,290

469.20

.0021

28.00

•943

68.08

1112.4

21,830

349 70

.0028

27.88