Page:Popular Science Monthly Volume 91.djvu/698

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What's Wrong with the Submarine?

A submarine boat is not perfect. Two sets of motors are needed — one to drive it on the surface and *he other under water. Why not use one set only?

By Frank Shuman

(A submarine boat must be driven under water by storage batteries for reasons given in this article. As a result, even the larger submarines are literally packed with machinery. Some of this could be dispensed with if one set of engines could be used for surface and under-water propulsion. Moreover, the dangers attending the use of storage batteries would be avoided. Mr. Frank Shuman, a distinguished mechanical engineer, famous for his wool-degreasing ma- chinery, his sun-power plant, his corrugated glass, his method of making concrete piles, has in- vented a very ingenious method of obtaining this desired end by utilizing liquid oxygen. — Editor.)

��IT seems very wonderful that, after centuries of effort, men have succeeded in building boats which can dive be- neath the surface of the water and come up again almost as readily as dolphins. Indeed, it is so wonderful that those who have only a general conception of the con- struction and operation of the submarine are apt to believe that the millenium in naval architecture has come. The truth is that for all its deadliness, the submarine is a very crude piece of machinery. The submarine serves the very useful purpose of

��taking the conceit out of mechanical en- gineers; it reveals to them how very much they have to learn about the generation of energy.

Every submarine in the world is driven on the surface by what are known as in- ternal combustion engines — engines which, in a general way, are similar to those by means of which automobiles are propelled. Such an engine is curiously human. It breathes air, just as you and I must breathe if we would live. A certain amount of air must be mixed with the liquid fuel of the

��Conning tower

��Electric steer

��Ventilators

��Hydroplane Officers quarters

Escape hatches Torpedoes

���Ancho

��How Liquefied Oxygen Is Turned into Gas under High Pressure to Generate Power

��Power generated from liquefied oxygen is utilized to operate first an expansion engine and then the regular explosion engine of the submarine. Liquid oxygen is intensely cold — so cold that it boils when exposed to the much hotter atmosphere. On shipboard it is kept in a container which prevents it from boiling away as much as possible. To convert it into a gas under pressure, it is pumped from the container through three successive coils before it reaches the expansion engine. In the first coil the liquefied oxygen is turned

��into gaseous oxygen under high pressure; the necessary heat is supplied by ordinary sea water running around the coil. In other words, heat is absorbed from the sea water, which heat furnishes the main power to drive the expansion engine. The gaseous oxygen is next superheated by passing through the second coil, the superheating being produced by using the cooling water which has been used to jacket the explosion engine of the submarine, around the coil. The now gaseous oxygen is still further superheated as it passes

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