126 BOILER TESTS. 



11.04 pounds of water per pound of combustible from and at 

 212 degrees. This is a favorable result considering the tem- 

 perature of the gases, which was 463 degrees. 



Boiler No. 22. 



Kind of boiler, Horizontal return tubular. 



Number used, ....... Two. 



Horse-power (collective, basis 12 square feet), Two hundred and twenty. 



Kind of coal, . . . . . . . Anthracite, Lehigh, egg. 



Age, Twelve years. 



Boiler No. 22 is of the ordinary horizontal tubular type, 

 arranged and set in the general manner shown in the cuts of 

 Boiler No. 3. In this case the flue gases pass directly to the 

 chimney, the top of the boiler being covered with brick work, 

 and the top of the bridge wall i g curved upward to conform to 

 the curve of the shell. This boiler is fitted with a much 

 smaller grate than is usually employed, and for this reason the 

 proportion of heating surface to grate surface, which is 68 to 

 1, is large, and that of the grate to tube area is small. 



Dimensions of Boiler No. 22. 



Diameter of shell, 60 in. 



Length between heads and length of tubes, . . . . 17 ft. 

 Number of tubes ( collective) 3 inches outside diameter, . 192 



Area of heating surface, 2,680 sq. ft. 



Area of grate surface, . . .. 39 sq. ft. 



Area through tubes, 7.9 sq. ft. 



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

 Ratio of heating surface to grate surface, . . . 68 to 1. 



Ratio of grate surface to tube opening, . . . , . 4.9 to 1. 



Results of Test, Boiler No. 22. 



Test No. 57. 



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



Duration, 10 hrs. 



Coal consumed, . . . 4,508 Ibs. 



Percentage of ash, 12.9 per cent. 



Water evaporated, 41,714 Ibs, 



Coal per hour, 450.8 Ibs. 



Coal per hour per square foot of grate, .... 11.5 Ibs. 



Water per hour, 4,171.4 Ibs. 



Water per hour per square foot of heating surface, . 1.6 Ibs. 



Horse-power developed, 124.2 H. P. 



Boiler pressure, 75 Ibs. 



