Operation of the Condenser.
The cold water, which is forced through by a circulating pump, enters at the bottom, and is compelled to pass forward through the lower set of tubes by a horizontal dividing plate; it then returns through the upper rows of tubes and passes out at the overflow; the tubes are thus maintained at a low temperature.
The tubes are made to pass right through the condensing chamber, and so as to have no connection with its internal space. The steam is passed into the condenser and there comes in contact with the cold external surface of the tube, and is condensed, and removed as before, by the air pump, as may be readily seen in the illustration ([p. 65.])
The advantages gained by the use of the surface condenser are: 1. The feed water is hotter and fresh; being hotter, it saves the fuel that would be used to bring it up to this heat; and being fresh it boils at a lower temperature. 2. Not forming so much scale inside the boiler, the heat passes through to the water more readily; and as the scum cock is not used so freely, all the heat that would have been blown off is saved. Its disadvantages are that being fresh water and forming no scale on the boiler, it causes the boiler to rust.
It is often said that one engineer will get more out of a ship than another. In general it will be found that the most successful engineer is the man who manages his stokers best. It is very difficult on paper to define what is meant. It is a thing to be felt or seen, not described. * * * * The engineer who really knows his business will give his fires a fair chance to get away. He will work his engines up by degrees and run a little slowly for the first few moments.