Such a structure is shown in [Fig. 22], in which three bladed wheels A, B, C, are caused to rotate, a set of stationary blades D, E, being placed between the three moving wheels, but the stationary blades are disposed in reverse directions. When the steam from pipes F, F, impinges against the blades of the first wheel A, it is directed by the stationary blade D to the next wheel B, and from the stationary blade E to the blades of the next wheel C, thus, in a manner somewhat similar to the compounding effect of the steam engine, utilizes the pressure which is not used at the first impulse.
FUELS AND COMBUSTION
All fuels must be put into a gaseous state before they will burn. This is true of coal as well as of hydro-carbon oils.
Neither coal nor petroleum will burn in its native state, without the addition of oxygen. This is absolutely necessary to support combustion. Burning is caused by the chemical union of oxygen with such substances as will burn.
This burning process may be slow, and extend over a period of years, or it may be instantaneous, in which latter case the expansion of the heated gases is so great as to cause an explosion. When a sufficient amount of oxygen has been mixed with a fuel to permit it to burn, a high temperature is necessary to cause the immediate burning of the entire mass.
If such a temperature is not present the course of combustion is not arrested, but it will, on its own account, start to oxydize, and eventually be reduced to the same condition that would take place if exploded by means of a flame.