106 SWEETENED CONDENSED MILK COOUNG 



with jacket and vertically suspended, revolving coil, has been 

 adopted in numerous factories with most satisfactory results, 

 and this method of cooling this viscous product promises to 

 assist in solving the cooling problem. Rectangular vats with 

 horizontal coils, which also have been tried for this purpose, 

 however, are less desirable, as they tend to cause the condensed 

 milk to foam excessively. This foaming is caused by the fact 

 that the horizontal coil revolves into the milk, beating air into 

 it. In the case of the circular tank, the vertical suspended coil 

 when revolving moves upward, out of the milk, thus avoiding 

 incorporation of air and excessive foaming. The circular vat 

 with the suspended vertical coil has the further advantage that 

 the condensed milk does not come in contact with bearings and 

 glands, these parts being entirely detached from the vat. 



A still more recent method of cooling sweetened condensed 

 milk consists of a combination of the use of the submerged coil 

 and subsequent slow agitation. The equipment for this method 

 consists of a vertical or horizontal tank, equipped with a sub- 

 merged coil. This coil should have a diameter of about H 

 inches and a length of from 600 to 700- feet, the length needed 

 depending on the temperature to which it is desired to cool the 

 condensed milk and the temperature of the cooling water. The 

 coil is usually of regular, so-called sanitary pipe (copper pipe 

 tinned on inside) or it may be black iron pipe preferably sand- 

 blasted on inside. 



The submerged coil connects at its intake with a high pres- 

 sure pump and at its outlet with one or more large enameled 

 steel holding tanks (capacity usually 5,000 gallons). Each of 

 these holding tanks is equipped with a powerful motor-driven, 

 vertically slanting agitator, also enameled. The agitator re- 

 volves at a speed of about 12 R. P. M. 



In the operation of this method of cooling, the hot sweet- 

 ened condensed milk is drawn from the vacuum pan, preferably 

 by gravity, into a standardizing vat mounted on scales. When 

 all the condensed milk of one and the same batch has been trans- 

 ferred to this tank it is accurately weighed. The weight of the 

 original fluid milk is then divided by the weight of the con- 

 densed milk. This yields the exact ratio of concentration. If 



