16 STEAM BOILER TESTS — ROBB. 



The equivalent dry fuel is found by multiplying the total 

 quantity of fuel by the percentag'e of moisture and dividing by 

 100, which is deducted from the total quantity of fuel. The 

 equivalent combustible is found by deducting the total amount 

 of ash from the total quantity of fuel. 



The water evaporated per hour is the total quantity of water 

 divided by the number of hours duration of test. 



The water evaporated per pound of dry fuel is the total quan- 

 tity of water divided by the total quantity of dry fuel. 



The water evaporated per pound of fuel from and at 212° is 

 found by multiplying the water evaporated per pound of fuel by 

 the total heat, or heat units, of one pound of steam at the average 

 pressure, less the total heat of one pound of feed-water befoie 

 entering the boiler or injector, if one be used, and dividing the 

 product by 966 which is the total heat, in units, of. one pound of 

 steam at 212°. 



The horse power is determined by deducting the total heat 

 units of one lb. of feed water at the average temperature before 

 entering boiler or injector, if one be used, from the total heat units 

 of one pound of steam at the average pressure, and multiplying the 

 product by the quantity of water evaporated per hour and divid- 

 ing by 1110, (which are the heat units required to raise one pound 

 of water fiora 100° and evaporate it at 70 lbs. pressure), the 

 quotient should be divided by 30, which will give the horse 

 power according to the American standard. The following is an 

 example of this method of finding the horse power. 



Total quantity of water evapoiated = 2000 lbs. 



Steam pressure (b}' guage), 60 lbs. 



Temperature of feed water before entering boiler or injector, 40°. 



Total heat of 1 lb. of steam at 60 lbs. pressure = ll75 B. T. TJ. 

 1 " feed water, at 40° = 8 B. T. U. 

 1175.7_S. X 2000 -^ 1110.3 = 210.33 - 30 = 70 H P. 



Example of finding the equivalent evaporation from and at 212°. 

 Water evaporated per lb. of fuel, 10 lbs. 

 Average pressure by gauge, 60 " 



" temperature of feed water, 40°. 



