80 UNITED STATES NATIONAL MUSEUM 



STEAM GENEEATING AND HEATING EQUIPMENT 



Boilers and steam m/iins. — For the production of steam there are 

 four Geary high-pressure water tube boilers, each with a nominal 

 rating of 175 horse power and carrying a steam pressure of 100 

 pounds. They are set in two batteries. Each boiler is made up of 

 100 4-inch tubes, 16 feet long, inclined at an angle of approximately 

 15° to the horizontal, and directly expanded into solid steam headers 

 with a steam drum, 24 inches in diameter, resting in a horizontal 

 position. The steam headers, one at the front and one at the back, 

 are riveted to and so connected with the drum that the circulation 

 of water is free and not retarded by contracted vein. 



The boilers are fired by means of automatic Taylor gravity feed 

 stokers, with forced draft obtained by means of a 6-foot Sturtevant 

 blower, driven by an engine of the same make. There are, in fact, 

 two of these engines, one on each side of the fan, one of which is kept 

 in reserve while the other is running. The stokers are operated by 

 means of a main shaft extending through the ash pit and connected 

 to the fan shaft by a silent chain drive. The speed of the fan and 

 stokers is regulated automatically through a Locke draft regulator. 

 When the speed drops below a predetermined point, which is 100 

 pounds pressure, a clamper regulator opens a valve furnishing steam 

 to the engine of the fan, thus increasing its speed and at the same 

 time the draft and the speed of the stokers. As soon as the steam 

 pressure exceeds another fixed point, namely 103 pounds, the regu- 

 lator stops the fan engine, thus closing down the draft and decreasing 

 the speed of the stokers. In this manner the fire in the furnaces is 

 controlled without the close attention of anyone. Williams' auto- 

 matic boiler feed regulators are used for maintaining the water in 

 the boilers at a constant level. 



A 9-inch steam main passes along and above the fronts of the 

 boilers, with which there are 6-inch connections through large radius 

 pipe bends to allow for expansion without undue strain on the main. 

 The main is carried back along the side of the outside boiler of 

 each battery, one branch continuing along the side of the engine 

 room, the other through the middle of the room, with 7-inch bend 

 connections to the three large engines and a 5-inch connection to the 

 smaller one. The two branches are brought together near the west- 

 ern end of the engine room, and contain numerous gate valves which 

 make it possible to cut any section of the main out of service for 

 repair without closing down the plant. 



The main exhaust line for the engines and pumps, 14 inches in 

 diameter, runs through the middle of the engine room in a large 

 trench under the flioor. At the western end of the room it rises and 

 passes along the adjoining corridor to the smoke stack, up which it 

 is carried to within about 10 feet of the top. The exhaust steam 



