147c CREAMERY BUTTER MAKING 



A is considerably larger than either of the other two. The 

 reason for this is that nearly all of the inorganic matter 

 remains in the bottom of this part of the tank, while the 

 organic matter, as already stated, gradually accumulates 

 at the surface in this section, in spite of constant de- 

 composition. This state of things must make it evident 

 that the first section of the tank must be cleaned at least 

 once in six months to remove the inorganic matter. 



It may be stated that for an ordinary creamery a tank 

 12 feet square by 4 l / 2 feet deep will be large enough, pro- 

 vided the water used for cooling is not run into it. It is 

 well to remember, however, that the larger the tank used 

 the better the results that may be expected from it. 



Flow of Sewage Through Tank. Four-inch tile, care- 

 fully laid, may be used to conduct the sewage from the 

 creamery to the tank. A trap is placed near the creamery 

 to shut off the odors coming from the drain. At the 

 point at which the sewage enters the tank it is desirable 

 to attach an elbow with an arm sufficiently long to keep 

 the lower end always in the sewage. This prevents un- 

 due mixing of the incoming sewage with that already in 

 the tank, a matter of the highest importance in the suc- 

 cessful operation of the tank. 



When the sewage in section A has reached the level X, 

 it begins to discharge into section B through three-inch 

 gas pipe as shown in Fig. i. The liquid is withdrawn 

 from a point near the middle of the tank as indicated by 

 the arrow. The eight-inch space above the discharge per- 

 mits the accumulation of organic matter. The discharge 

 from B into C, and from C into the drain is the same as 

 that from A into B ; but the discharge pipes are of neces- 

 sity lower by an amount indicated by the dotted lines. 



