Ultimate Guide to Farm Mechanics: A Practical How-To Guide for the Farmer by Fred Crawshaw Emil Lehmann Byron Halsted James Stephenson

Author:Fred Crawshaw, Emil Lehmann, Byron Halsted, James Stephenson
Format: epub
Publisher: Perseus Books, LLC
Published: 2014-12-31T16:00:00+00:00

CHAPTER VII

POINTS FOR THE YOUNG ENGINEER

QUESTIONS AND ANSWERS

THE BOILER

Q. How should water be fed to a boiler?

A. In a steady stream, by use of a pump or injector working continuously and supplying just the amount of water required. By this means the water in the boiler is maintained at a uniform level, and produces steam most evenly and perfectly.

Q. Why should pure water be used in a boiler?

A. Because impure water, or hard water, forms scales on the boiler flues and plates, and these scales act as nonconductors of heat. Thus the heat of the furnace is not able to pass easily through the boiler flues and plates to the water, and your boiler becomes what is called “a hard steamer.”

Q. What must be done to prevent the formation of scale?

A. First, use some compound that will either prevent scale from forming, or will precipitate the scale forming substance as a soft powder that can easily be washed off. Sal soda dissolved in the feed water is recommended, but great care should be exercised in the use of sal soda not to use too much at a time, as it may cause a boiler to foam. Besides using a compound, clean your boiler often and regularly with a hand hose and a force pump, and soak it out as often as possible by using rain water for a day or two, especially before cleaning. Rain water will soften and bring down the hard scale far better than any compound.

Q. How often should you clean your boiler?

A. As often as it needs it, which will depend upon the work you do and the condition of the water. Once a week is usually often enough if the boiler is blown down a little every day. If your water is fairly good, once a month will be often enough. A boiler should be blown off about one gauge at a time two or three times a day with the blow-off if the water is muddy.

Q. How long should the surface blow-off be left open?

A. Only for a few seconds, and seldom longer than a minute. The surface blow-off carries off the scum that forms on the water, and other impurities that rise with the scum.

Q. How do you clean a boiler by blowing off?

A. When the pressure has been allowed to run down open the blow-off valve at the bottom of the boiler and let the water blow out less than a minute, till the water drops out of sight in the water gauges, or about two and one-half inches. Blown off more is only a waste of heat and fuel.

Q. What harm will be done by blowing off a boiler under a high pressure of steam?

A. The heat in the boiler while there is such a pressure will be so great that it will bake the scale on the inside of the boiler, and it will be very difficult to remove it afterward. After a boiler has been blown off the scale should be for the most part soft, so that it can be washed out by a hose and force pump.

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