222 BOILER TESTS. 



Area through flue, 9.8 sq. ft. 



Width of air spaces and metal bars in grates, . Air 3-8 in., metal 1-4 in. 

 Ratio of heating surface to grate surface, .... 40.3 to 1 

 Ratio of grate to flue area, 6.1 to 1 



Results of Test, Boiler No. 66. 



Test No. 131. 

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



Duration, ........... 10.5 hrs. 



Coal consumed, ......... 5,553 Ibs. 



Percentage of ash, . . 9.2 percent. 



Water evaporated, . 45,803 Ibs. 



Coal per hour, 528.8 Ibs. 



Coal per hour per square foot of grate, .... 17.8 Ibs. 



Water per hour 4,362.2 Ibs. 



Water per hour per square foot of heating surface, . . 3.6 Ibs. 



Horse-power developed, . . . . . . . 133.1 H. P. 



Boiler pressure, 73 Ibs. 



Temperature of feed water, 183 cleg 



Temperature of escaping gases, ..... 540 deg. 



Water per pound of coal, ....... 8.24 Ibs. 



Water per pound of coal from and at 212 degrees, . .8.77 Ibs. 

 Water per pound of combustible from and at 212 degrees, . 9.68 Ibs. 



The test on Boiler No. 66 shows the performance of a water 

 tube boiler, which had favorable proportions and used a 

 standard grade of coal, but which was operated under unfavor- 

 able conditions in respect to capacity. The rate of combustion 

 was 17.8 pounds of coal per square foot of grate per hour, 

 which, for the class of fuel used, is too high for economical 

 work. The horse power developed was one-third above the 

 rating. The evaporative result is low compared with the best 

 practice, and the high temperature of the escaping gases, 

 which was 540 degrees, reveals the cause of the inferior per- 

 formance. At the close of the test it was found that some of 

 the partitions were disarranged, thereby allowing at certain 

 points a free passage of the products of combustion along the 

 tubes to the flue. This defect was largely the cause of the 

 high temperature of the gases. 



Boiler No, 67. 



Kind of boiler, Water tube. 



Number used, ..... One. 

 Horse-power ( basis 12 square feet ), Seventy. 



Kind of coal Anthracite Lehigh, chestnut No. 2. 



Age, ....... Six months. 



