BOILER No. 34, 145 



good results. The use of the heater was attended by a reduc- 

 tion of 115 degrees in the temperature of the gases, these 

 entering the heater at 346 degrees, and leaving it at 231 

 degrees. The temperature of the water was raised from 9 5 to 

 175, or 80 degrees. Comparing the \ two evaporative results, 

 the water per pound of coal was increased from 7.97 to 8.80 

 pounds, or 10.5 per cent. The economic result produced when 

 the heater was not in use, compares favorably with that 

 obtained in good practice, considering the inferior grade of 

 coal that was employed. 



Boiler No. 34. 

 Kind of boiler, ...... Horizontal return tubular. 



Number used, ...... One. 



Horse-power (basis 12 square feet), . . Sixty-five. 



Kind of coal, ... . . Bituminous Walston. 



Age, ........ Four years. 



Boiler No. 34 is an ordinary horizontal tubular boiler, 

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

 Boiler No. 5. 



Dimensions of Boiler No. 34. 



Diameter of shell, . . . . . . . . . 54 in. 



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



Number of tubes three inches outside diameter, . . .71 



Area of heating surface, 783 sq. ft. 



Area of grate surface, 24 sq. ft. 



Area through tubes, ......... 2.9 sq. ft. 



Area through flue 3.1 sq. ft. 



Height of chimney, 50 ft. 



Width of air spaces and metal bars in grates, Air 5-16 in., metal 1 1-8 in. 



Distance of grate to shell, 18 in. 



Distance of flat bridge to shell, . . . . . . . 7 in. 



Ratio of heating surface to grate surface, .... 32.2 to 1 



Ratio of grate surface to tube area, 8.3 to 1 



Eesults of Test, Boiler No. 34. 



Test No. 71. 



Manner of start and stop, . . . . I Ordinary, withprelimi- 



\ nary heating. 



Kind of run, ... Continuous. 



Duration, 8.6 hrs. 



Coal consumed, dry (including wood equivalent), . 2,562 Ibs. 



Percentage of ash, 7.3 per cent. 



