174 



BOILER TESTS. 



The test on Boiler No. 46 had for a principal object the 

 determination of the economy of using a flue heater with 

 horizontal tubular boilers, which were already provided with a 

 large area of heating surface, the ratio of which to grate sur- 

 face was 58 to 1. The heater reduced the temperature of the 

 gases 361 254 = 107 degrees, and increased the tempera- 

 ture of the feed-water 145 79 = 66 degrees, and secured 

 thereby an increase in the evaporation per pound of coal 

 amounting to 7 per cent. If the results of Test No. 91 

 are applied to the plant as a whole, the evaporation per pound 

 of combustible from and at 212 degrees becomes 12.68 pounds. 

 Looked at in this way, the performance is exceedingly high 

 for this or any other type of boiler, and it shows what may be 

 attained by employing an ample area of heating surface, 

 arranged in such a manner as to properly absorb the heat. 

 Without the heater, the economy obtained is below the best 

 performance of ordinary horizontal tubular boilers. 



Boiler No. 47. 



Kind of boiler, . 



Number used, . 



Horse-power (collective, basis 



Kind of coal, 



Age, 



Plain cylinder. 

 Four. 



sq. ft. ), Two hundred and twenty. 

 Anthracite, chestnut No. 2. 

 Ten years. 



BOILER No. 47, CROSS SECTION THROUGH FURNACE. 



