106 SWEETENED CONDENSED MrtK—CooLInG 
with jacket and vertically suspended, revolving coil, has been 
adopted in numerous factories with most satisfactory results, 
and this methed of cooling this viscous product promises to 
assist in solving the cooling problem. Reetangular 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 
elands, 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 14 
inches and a length of from 600 to 70O 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 seales. 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 exaet ratio of concentration. If 
