198 



BOILER TESTS. 



Boiler No. 55 consists of a 

 plant of five vertical tubular 

 boilers of the type shown in 

 the following cut. This boiler 

 consists of a plain vertical 

 shell, containing tubes placed 

 in two sections, arranged with 

 an open space between them 

 for purposes of inspection and 

 cleaning. It is set with a 

 brick furnace, the walls of 

 which extend about half way 

 up on the sides of the boiler. 

 Above this point the shell is 

 covered with non-conducting 

 cement. The boilers are fitted 

 with tubes having an external 

 diameter of 3 inches, which is 

 somewhat larger than those 

 ordinarily used for vertical 

 boilers. 



Tests No. 113 and No. 

 114 were made on the full 

 plant of five boilers, while 

 tests No. 115 and No. 116 



were made on a single boiler of the plant. The first 

 three tests show the performance of the boilers with anthra- 

 cite coal, working under three different rates of combus- 

 tion, the highest being 14.3 pounds per square foot of grate 

 per hour, and the lowest 9.3 pounds. There is a continuous 

 improvement in the evaporative result as the rate is decreased, 

 though the best result obtained cannot be looked upon as 

 favorable. The highest performance is 8.96 pounds of water 

 from and at 212 degrees per pound of combustible, with 71 

 degrees of superheating. The low degree of economy which 

 was realized may be attributed in part to the high temperature 

 of the escaping gases, and in part to loss produced by radia- 



BOILER No. 55, VERTICAL 

 ELEVATION. 



