90 



BOILER TESTS. 



diameter of about 1-4 of an inch. The air which is fed to 

 the bridge wall pipe first passes through the air spaces in the 

 side walls of the setting, by which means it is somewhat heated. 



BOILER No. 9, LONGITUDINAL SECTION. 



Dimensions of Boiler No. 9. 



Diameter of each shell, 



Length between heads and length of tubes, 

 Number of tubes 3 inches outside diameter, . 



Area of heating surface, 



Area of grate surface, ...... 



Area through tubes, ....... 



Area through chimney, 



Height of chimney, ....... 



Width of air spaces and metal bars in grate, . 

 Distance of grate to shell, .... 



Distance of flat bridge wall to shell, 

 Ratio of heating surface to grate surface, 

 Ratio of grate surface to tube area, 



Air 3-8 in. 



60 in. 



15 ft. 

 66 



890 sq. ft. 



25.7 sq. ft. 



2.7 sq. ft. 



7 sq. ft. 



90 ft. 



metal 1-2 in. 



26 in. 



9 in. 



34.6 to 1 



9.4 to 1 



