SWEETENED CONDENSED MiILK—CONDENSING 83 
little danger of milk being carried over into the condenser in 
quantities sufficient to be of any consequence. Under these 
‘conditions the installation of a special milk trap between the 
pan and the condenser for the purpose of collecting the escaping 
milk spray and carrying it back to the pan is, therefore, an 
unnecessary expense. 
If the pan is small in comparison to the amount of milk to 
be condensed, and if it is forced beyond its intended capacity so 
that the milk boils up high, there usually is considerable loss of 
milk, as indicated by the foaminess and milky color of the ex- 
haust of the vacuum pump. In such cases the mechanical loss 
of an average size batch may amount to several hundred pounds 
of milk. In order to not lose this milk, a milk trap or catch-all 
may be installed between the pan and the condenser. The vapors 
laden with the milk spray enter the trap near the top. The 
spray drops to the bottom of the trap, while the vapors are drawn 
over into the condenser, where they are condensed as usual. 
This trap may be constructed of sufficient size so as to serve 
as a reservoir to collect all the milk that is carried over, and at 
the conclusion of the process the contents of the trap are drawn 
from the bottom and are condensed with the next batch; or the 
bottom of the trap may be connected with the pan so that the 
milk thus carried over flows back into the pan automatically, 
In this case a small trap only is necessary. 
It should be understood that the milk trap is only a remedy 
and not a preventive. Where the capacity of the pan is in pro- 
portion to the amount of milk to be condensed, as it should be, 
and where the pan is operated properly, the trap is unnecessary. 
The trap is an additional piece of apparatus to be kept clean. 
Unless it is so constructed that access can be had to all parts 
of its interior and unless it 
really is kept clean at all times, 
it may become a serious source 
of contamination. 
The Vacuum Pump.—The 
vacuum pump is, strictly speak- 
ing, not a part of the vacuum 
pan, but its intimate connec- 
tion with the pan makes it 
Fig. 30. Wet-vacuum pump 
Courtesy of Arthur Harris & Co. 
