APPLICATION OF KEFKIGERATION TO HANDLING OF MILK. 83 
to do the actual churning, and about 20 minutes more to work the 
butter. During this time the cream ripeners are washed. 
The arriving cream from the auxiliary creameries or farms is 
weighed, sampled, and pasteurized. The pasteurizing may be done 
either in the ripening vats or in a separate pasteurizing machine. 
When the cream is pasteurized in the ripening vats it is cooled by 
running cold water through the coils and the jacket surrounding the 
vat. When a separate machine is used, the cream is run over a 
cooler on its way to the ripening vats, where it is held at the proper 
temperature for ripening from 18 to 20 hours. After the churning 
is finished and the butter packed in tubs or boxes and stored in the 
refrigera.tor, the churns and other apparatus are washed as well as 
the floors of the building. The afternoons are usually given up to 
office work, making repairs, etc. The machinery is, therefore, 
operated only about eight hours a day; consequently, the refrigerating 
machine should be of sufficient capacity to do the work in about eight 
hours' time. 
The size of the room necessary to accommodate a creamery making 
2,000 pounds of butter daily is about 10 by 10 by 10 feet, giving 
600 square feet surface. Assuming that the walls, floors, and ceiling 
are insulated for a heat transmission of 2 B. T. U. per square foot 
per 24 hours for each degree of difference between the inside and 
outside temperature, then with an average outside temperature 
of 80° F. the refrigeration necessary is: 
b. t. u. 
Removing heat corning through walls, floors, and ceiling, 600X2(80°-32°). . . 57, 600 
Cooling cream, 5,500 X.90(75°-50°) 123, 750 
Cooling butter, 2,000X.5494(58°-32°) 28, 568 
209, 918 
In view of the fact that the greater part of the refrigeration is 
required for cooling the cream, an increase of 25 per cent to com- 
pensate for losses of various kinds should be ample. Therefore, the 
total amount of refrigeration necessary in 24 hours is 262,398 B. T. U. 
But as the work is to be accomplished in 8 hours, the capacity of the 
9g2 398 X 3 
machine necessary is: ^ QQQ ' =2.73 tons, say, 3-ton machine. 
The cooling of the cream will take about one hour and the amount 
of brine necessary, allowing a 10° rise in brine temperature, is 
123,750 = 238 cubic £ eet ^ ^thout the aid of the machine at the time. 
oZi\J 
With the machine running during the time the cooling takes place, 
', . • 123,750-36,000 1co .,. 
the cubic feet of brine necessary is ^q = io». Alter 
the cream is cooled and run into the vats for ripening, the brine 
is cooled down for holding over the room temperature during the 
