118 STEAM BOILERS 



In water-tube boilers of the Heine type, in the front course 

 of the drum, not less than 6 in. from the bottom of the drum, 

 and projecting through the sheet not less than 1 in. 



In Robb-Mumford boilers of standard type, in the bottom 

 of the steam and water drum, 24 in. from the center of the rear 

 neck, and projecting through the sheet not less than 1 in. 



In water-tube boilers of the Almy type, in a tube directly 

 exposed to the products of combustion. 



In vertical boilers of the Climax or Hazelton type, in a 

 tube or center drum, not less than one-half the height of the 

 shell, measuring from the lowest circumferential seam. 



In Cahall vertical water-tube boilers, in the inner sheet of 

 the top drum, not less than 6 in. above the upper tube sheet. 



In Scotch marine-type boilers, in the combustion-chamber 

 top, and projecting through the sheet not less than 1 in. 



In dry-back Scotch-type boilers, in the rear head, not less 

 than 2 in. above the top row of tubes, and projecting through 

 the sheet not less than 1 in. 



In Economic-type boilers, in the rear head, above the upper 

 row of tubes. 



In cast-iron sectional heating boilers, in a section over 

 in direct contact with the products of combustion in 

 primary combustion chamber. 



In other types and new designs, fusible plugs shall be pi 

 at the lowest permissible water level, in the direct path of 

 products of combustion, as near the primary combusti 

 chamber as possible. 



Connection of Steam Gauge. A steam gauge should 

 connected to the boiler in such a manner that it will neither 

 injured by heat nor indicate incorrectly the pressure to which 

 it is subjected. To prevent injury from heat, a so-called 

 siphon is placed between the gauge and the boiler. This' 

 siphon in a short time becomes filled with water of condensa- 

 tion, which protects the spring of the gauge from the injury 

 the hot steam would cause. Care should be taken not to 

 locate the steam-gauge pipe near the main steam outlet of the 

 boiler, as this may cause the gauge to indicate a lower pressure 

 than really exists. In locating the steam gauge, care must 

 also be taken not to run the connecting pipe in such a manner 



