File:The steam-engine and other heat-motors (1909) (14750158366).jpg

Identifier: steamengineother00crei (find matches)
Title: The steam-engine and other heat-motors
Year: 1909 (1900s)
Authors: Creighton, William Henry Paul, 1859-
Subjects: Steam-engines Heat-engines
Publisher: New York, J. Wiley & sons (etc., etc.)
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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so that the watermay be heated above 212° F. This heater is best suited towater which is free from scale-forming deposits and volatilegases. For instance, carbonates are precipitated when the C02is driven out of the water. In closed heaters if the C02 is notdriven off these salts will be deposited on the boiler tubes. Thiswill happen if the valve placed for this purpose on the heateris not opened to permit the gases to escape. The closed type of heater is subject to boiler pressure and thecorresponding strains and accidents; it is not as economical asthe open heater, and becomes less so as the tubes become coveredwith scale; it is difficult to remove the scale from its tubes; acoating of oil on its tubes renders them less efficient; the con-densed steam is ordinarily wasted; the precipitate does notsettle owing to the agitation of the water. It is extremely desirable to reduce the amount of gases passing 252 THE STEAM-ENGINE AND OTHER HEAT-MOTORS. FEED\WATER OUTLET EXHAUSTSTEAM INLET
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EXHAUST•STEAM OUTLET FEEDWATEff /NLET WHEELER CONDENSER \ ENGINEERING GOSFEED WATER HEATER Fig. 136. CONDENSERS AND AIR-PUMPS. 253 into the condenser when high vacua are desired. These gasesinterfere with the economy of the condenser and increase mate-rially the load on the air-pump. In the open heaters thesegases are driven out automatically. In the design of a closed heater, in addition to the properlyarranged heating surfaces to abstract all the heat possible fromthe steam, other requirements arise from the necessity of main-taining that efficiency with the least amount of trouble. Beingunder boiler pressure the heads must be stayed if not thickenough to withstand expected pressures. Grease may be re-moved by gentle boiling in a strong alkali and scale by subse-quent boiling in a weak acid solution. Do not mix the acid andalkali. Percentage Gain in Using Feed Heaters.—The theoretical gainin percentage by the use of feed-water heaters is easily shown. Let #=B.T.U. in one pound o

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