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BELL SYSTEM TECHNICAL JOURNAL 



between will contain the steam and oil piping, oil handling machinery, 

 etc. This is a three-tank pit with space for two tanks shown. 



In order to provide dry pits for the equipment below the treating 

 tank bottoms and also to facilitate removal of a tank from the ground 

 in case it might need repair, it has been found desirable to build 

 concrete foundations and walls around the treating tanks. 



I'ig. 26 — TriMliiiH Tanks in Plac 



A few inches of space is left between the concrete retaining walls 

 and the sides of the treating tanks. This space serves two purposes: 

 it permits placing or removing the tanks with ease and it also pro- 

 vides air spaces around the sides of the tanks, which tend to insulate 

 them from the ground. As has been mentioned, it is necessary to 

 change the temperature of the oil in the tanks quickly from about 

 220° to about 105° Fahrenheit. There is very little lag in making the 

 tem]>erature change due to heat retained by the tank walls. However, 

 if the ground around the tanks were wet and in contact with them, 

 considerable lag would be e.xperienced in making the temperature 

 change of the oil because of heat which would be retained by the 

 ground. 



The poles in the tanks as shown by Fig. 2G rest in a position 

 inclined slightly back toward the racks so that they remain in this 



