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BELL SYSTEM TECHNICAL JOURNAL 



which are immersed in oil along the inside of the tanks after the poles 

 are in place. In the cold and hot tanks the temperature does not 

 change rapidly, so their temperatures can be read by means of station- 

 ary- indicating thermometers mounted on the sides of the tanks and 

 ha\ing bulbs which project into the insides of the tanks through 

 suitable fittings. The oil temperatures, of course, are controlled by 

 the steam valves to the radiators in the \arious tanks. 



l-'ig. M) — Steam Boiler During [nslallalioii 



Oil. II.WDMNG 



The heart of the oil handling apparatus, of course, is the centrifugal 

 pump which has been mentioned and which is direct connected to the 

 20 H.P. steam turbine. In some of the smalU-r i)lants ilie centrifugal 

 pumps are ofierated by .5 H.P. gasoline engines. 



lioth cold oil and hot oil are fed from the storage tanks to the 

 treating tanks by gravity. The centrifugal pimip is used for returning 

 the oil from the treating tanks to the proper storage lank, for moving 

 it from one storage tank to another or for delixering oil from the tank 

 cars to the storage tanks. 



Since the creosote which is used in pole treating ma\' solidify at 

 any temperature below 100° Fahrenheit, even in comparatively warm 

 weather it is sometimes necessiiry to provide a steam connection to 



