BOILER No. 17. 



117 



BOILER No. 17, CROSS SECTION THROUGH FURNACE. 



BOILER No. 17, LONGITUDINAL SECTION. 



Dimensions of Boiler No. 17. 



Diameter of shell, 48 in. 



Length between heads and length of tubes, . . . . 12 ft. 



Number of tubes ( collective ) 3 inches outside diameter, 147 



Area of water-heating surface, 1,548 sq. ft. 



Area of steam-heating surface, 185 sq. ft. 



Area of grate surface, . . . . . . . .58.5 sq. ft. 



Area through tubes, 6.1 sq. ft. 



Height of chimney, . . . , . . . . 140 ft. 

 Width of air spaces and metal bars in grates, Air 7-16 in., metal 3-8 in. 



Distance of grate to shell, . . . . . . . 16 in. 



Distance of flat bridge to shell, 5 in. 



Ratio of water-heating surface to grate surface, . . 26.5 to 1 



Ratio of grate to tube area, . . . . , . 9.6 to 1 



