STEAM 



97 



Barrel Calorimeter. It is a rather difficult matter to make 

 a very exact determination of the moisture contained in steam. 

 The apparatus or instrument used for this purpose is called a 

 calorimeter. There are many more or less complicated calori- 

 meters, but about the simplest and most available one for 

 general use is the so-called barrel calorimeter, shown in the 

 accompanying illustration. A 

 barrel or tank a holding 400 

 or 500 Ib. of water is placed on 

 a platform scales b, filled with 

 water, and weighed. The tem- 

 perature of the water is regis- 

 tered by a thermometer inserted 

 in the side of the barrel. Steam 

 from the boiler is led through 

 a hose c into the barrel until 

 the temperature of the water 



reaches 130 to 140 F. The steam is then turned off and the 

 barrel and its contents are again weighed. The difference 

 between this weight and the original weight is the weight of 

 the steam led in from the boiler and condensed in the barrel. 

 The average steam pressure throughout the process must be 

 observed. It is well to have the tube bent as shown in the 

 figure. 



The weight of the cold water and the rise in its temperature 

 are known, and so also is the weight of the mixture of steam 

 and water that is led in from the boiler. From the Steam 

 Table, the temperature of the steam can be found, since the 

 average pressure is known. Now, if dry steam comes through 

 the hose c, the condensation of this steam should raise the 

 temperature of the cold water in the barrel a certain amount. 

 If the temperature is not raised that much, it must be because 

 some of the mixture led into the barrel was water. 



Let Q = quality of steam; 



W = weight of cold water in barrel, in pounds; 

 w = weight of mixture run into the barrel, in pounds; 

 t = temperature of steam corresponding to the observed 



pressure ; 

 ti = original temperature of water, in barrel; 



