82 



BOILER TESTS. 



Boiler No. 6 is a horizontal 

 tubular boiler, set in brick-work 

 in the manner shown in the fol- 

 lowing cuts. It is located at the 



o 



end of a battery of boilers of the 

 same kind, and during the pro- 

 gress of the tests all the boilers 

 were in operation. The arrange- 

 ment of the setting is such that 

 air is admitted over the fire in a 

 finely divided state. For this 

 purpose perforated plates are in- 

 troduced in the side walls of the furnace and in the top of the 

 bridge wall, and the air is supplied through these plates from 

 ducts extending back and forth through the walls. 



BOILER No. 6, CROSS SECTION 

 THROUGH FURNACE. 



BOILER No. 6, LONGITUDINAL SECTION. 



Dimensions of Boiler No. 6. 

 Diameter of 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, 



Width of air spaces and metal bars in grates, 

 Distance of grate to shell, ...... 



Distance of bridge wall to shell, . . . . 



Ratio of heating surface to grate surface, . . 

 Ratio of grate surface to tube area, .... 



