48 



Condensed Milk and Milk Powder 



Fig. 11. Steam coils 



Courtesy of Arthur Harris & Co. 



condensation of the steam in the jacket and coils. If the heating 

 surface is inadequate, more steam has to be turned into the jacket 

 and coils, in order to secure the necessary heat for rapid evapora- 

 tion, than will condense ; free steam will blow through and out of the 



coils, resulting in uneconomic 

 and wasteful use of fuel, and 

 jeopardizing the quality of the 

 product. A properly construct- 

 ed six-foot pan usually has not 

 less than one hundred twenty to 

 one hundred thirty square feet 

 of heating surface. 



Jacket and coils are con- 

 nected independently with the 

 direct steam main from the 

 boiler. Each connection at the 

 pan should carry a valve and a 

 steam gauge on the pan-side of 

 the valve. The main steam line 

 and connections leading to pan should be properly insulated by 

 proper pipe coverings, in order to supply the pan with as dry steam 

 as possible. 



The drips or discharge ends of the jacket and coils are con- 

 nected with the boiler feed water tank. If the pan has sufficient 

 heating surface and is operated properly, the drip ends of the jacket 

 and coils should discharge warm water only, and not free steam. 

 The jacket and coils should be free at the drip or discharge ends 

 so that all condensation water may be quickly and continuously re- 

 moved. This is necessary in order to make the most economical 

 use of the steam and to secure high efficiency of evaporation. In 

 order to guard against back pressure the drips may be equipped 

 with suitable check valves. 



Through the walls of the body of the pan also enters the milk 

 draw pipe. This pipe connects with the hot well and through it the 

 milk rushes into the pan. Immediately outside of the pan the milk 

 pipe should be equipped with a valve to regulate the inflow. The 

 size of the milk draw pipe and valve, is governed by the capacity of 

 the pan ; usually two to three inches in diameter. Inside of the pan 

 the milk pipe should be turned down. If this provision is not made, 



