216 BOILER TESTS. 



and the arrangement of the setting are the same as shown in 

 the cut of Boiler No. 61. The whole exterior of the various 

 sections is exposed to the heat, and the surface above the 

 water line is thus made steam heating surface. The boilers 

 had been in use several years, and their interior surfaces had 

 become coated to some extent with scale, which had never 

 been removed. 



Dimensions of Boiler No. 63. 



Area of water-heating surface, 1,687 sq. ft. 



Area of steam-heating surface. ...... 562 sq. ft. 



Area of grate surface 69.7 sq. ft. 



Width of air spaces and metal bars in grates, . . .1-2 in. 

 Ratio of water-heating surface to grate surface, . . . 24.2 to 1 

 Ratio of steam-heating surface to grate surface, . . . 8 to 1 



Results of Test, Boiler No. 63. 



Test No. 128. 

 Manner of start and stop and kind of run, .... Ordinary. 



Duration, 104 hrs. 



Coal consumed, dry (including wood equivalent), . 6,580 Ibs. 

 Percentage of ash, ........ 12.4 per cent. 



Water evaporated, 48,059 Ibs. 



Coal per hour, 660.2 Ibs- 



Coal per hour per square foot of grate, .... 9.47 Ibs. 



Water per hour, . . 4,641.9 Ibs. 



Water per hour per square foot of water-heating surface, 2.8 Ibs. 



Horse-power developed 155.2 H. P. 



Boiler pressure, 54.7 Ibs. 



Temperature of feed- water, . . . . . . 92.6 deg. 



Temperature of escaping gases, 462 deg. 



Number of degrees of superheating, .... 29 deg. 



Draught suction, 0.09 in. 



Water per pound of coal, ...... 7.30 Ibs. 



Water per pound of coal from and at 212 degrees, . 8.41 Ibs. 



Water par pound of combustible from and at 212 degrees, 9.61 Ibs. 

 NOTE. The coal when fired contained 3.7 per cent, of moisture. 



The test on Boiler No. 63 shows the performance of a cast- 

 iron sectional boiler, using Cambria bituminous coal. This 

 boiler worked under many unfavorable conditions, and the 

 economic result of the test is inferior to the best practice. 

 The ratio of water heating surface to grate surface is small, 

 and the efficiency of this surface had become reduced by age, 

 so that the escaping gases passed to the chimney at a high 



