BOILER No. 59. 

 Eesults of Tests, Boiler No. 59. 



207 



NOTE. The coal when fired contained 3 per cent, of moisture. 



The tests on Boiler No. 59 had for a principal object the 

 determination of the economy secured by the use of a flue 

 heater in connection with vertical boilers. They are of special 

 interest in view of the large amount of waste heat which 

 ordinarily escapes to the flue in this type of boiler. In test 

 No. 121 the heater was in operation, while in test No. 122 the 

 heater was shut off, and the gases passed directly to the 

 chimney. The employment of the heater reduced the temper- 

 ature of the escaping gases 618 365= 253 degrees, and 

 increased the temperature of the feed water 225 88 = 137 

 degrees, resulting in an increase of the evaporation per pound 

 of coal of 7.10 to 9.16 pounds or 29 per cent. When the 

 heater was not in use, the economy secured was noticeably 



