A Practical Manual On Sea Water Distillation
With A Description Of The Necessary Machinery For The Process

STEAM, 45 we propose to compare are 10 lbs., 25 lbs., and 75 lbs. to the square inch. First.—Take a primary steam pressure of 10 lbs. per square inch inside the coil. We find, by the foregoing Table E, that its sensible, heat is 239°, and that this is 27° above 212°, the temperature of the boiling sea water outside the coil, and that the latent heat of this primary steam at this pressure is 946 units. If there is this pressure of steam inside the coil, and the water outside of the coil is at a temperature of 212°, and has to be converted into steam at ordinary atmospheric pressure, the latent heat required for this purpose will be as 946 : 966 :: 1: 1’021, or 946 x 1'02, which equals 964 units. The primary steam will also have been converted into 1 lb. of primary water, which will then escape, with a tem- perature of 239°, the sensible heat of the steam at 10 lbs. pressure. Secondly.—Take a pressure of 25 lbs. per square inch. This, by Table E, is shown to have a sensible heat of 266°, which is 54° above 212°, the boiling point of the water outside of the coil. The latent heat required to convert it into steam is still 966°. As the latent heat of the primary steam at a pressure of 25 lbs. per square inch is 927 units, the latent heat, therefore, required, to convert the 1 lb. of boiling water into steam will be as 927 : 966 :: 1 : 1'042, or 927 x 1'042, which equals 964. Thirdly.—Take primary steam at 75 lbs. pressure, the temperature of which is 320°—that is, 108° above 212°— and the latent heat of such primary steam 889°. To provide the 966 units of heat to convert the 1 lb. of boiling water into steam), the 889 units of latent heat must be multiplied by 1’087, which equals 966 (as 889 : 966 :: 1 : 1’087).