STEAM 



STEAM 



PROPERTIES OF STEAM 



Saturated Steam. If water is put in a closed vessel and 

 heat is applied until boiling occurs and steam is given off, the 

 pressure and the temperature of the steam will be the same as 

 those of the water. The steam thus produced is known as 

 saturated steam; that is, saturated steam is steam whose tem- 

 perature is the same as that of boiling water subjected to the 

 same pressure. Its nature is such that any loss of heat will 

 cause some of the steam to condense, provided the pressure is 

 not changed. Saturated steam that carries no water particles 

 with it is called dry saturated steam; if it contains moisture, 

 it is called wet steam. At every different pressure, saturated 

 steam has certain definite values for the temperature, the 

 weight per cubic ft., the heat per lb., and so on. These various 

 values, collected and arranged in order, form the table of the 

 Properties of Saturated Steam, more commonly termed the 

 Steam Table. This table is shown on the following pages. 



The various properties of steam, with their symbols, as given 

 in the Steam Table, are as follows: 



1. The temperature, t, of the steam, which is the boiling 

 point of the water from which the steam is formed. 



2. The heat of the liquid, q, which is the number of B. T. U. 

 required to raise the temperature of 1 lb. of water from 32 F. 

 to the boiling point corresponding to the given pressure. 



3. The latent heat of vaporization, r, often termed the latent 

 heat, which is the number of B. T. U. required to change 

 1 lb. of water at the boiling point into steam at the same 

 temperature. 



4. The total heat of vaporization, H, often termed the total 

 heat, which is the number of B . T. U. required to raise 1 lb. of 

 water from 32 F. to the boiling point for any given pressure 

 and to change it into steam at that pressure. It is the sum of 

 the heat of the liquid and the latent heat. 



