39 



enough to compensate for the extra labor required in cleaning the sep- 

 arator and utensils. There is also the fact that the separator bowl will 

 need to be retinned often if separating pasteurized milk. 



The plan followed at the Dairy _ Department at the present time is 

 to heat the milk to about 95 degrees before separating. The cream 

 is delivered from the separator into the pasteurizer and heated to 180 

 to 185 degrees. The sklm-milk is elevated by a rotary pump and just 

 before entering the tank it passes through a heater in which ex- 

 haust steam from the engine is used for pasteurizing the skim-milk. The 

 cut will show how this heater may be made. A union should be put in the 

 steam pipe somewhere near the heater, as the heater will need to be taken 

 apart at intervals to be cleaned. This can best be done by burning in the 

 furnace. The amount of milk, and the temperature to which it is heated 

 will determine how often it should be cleaned. Usually it will run from 

 six to eight weeks without requiring to be cleaned. 



A great saving in fuel can be made by utilizing the exhaust steam 

 from the engine. At the Dairy Department the pipes are so arranged that 

 the exhaust steam can be used for heating the whole milk before separate 

 ing, heating water, pasteurizing the skim-milk, and heating the building. 

 Two other labor and trouble saving devices are in use at the dairy 

 which are worthy of special mention. One is a skim-milk weigher which 

 after four year's use we would find it very difficult to get along without. 

 The other is an Ideal hoist for elevating milk at the intake. Having the 

 driveway graded so that no lifting of the can is required is the best plan, 

 but where this cannot be accomplished, the Ideal hoist would seem to be a 

 very satisfactory means of elevating the milk. 



Pulleys and Belting. The following rules for finding the size oi 

 pulleys, and the required length of belting will be found useful, in fitting 

 up a creamery or in placing additional machinery. 



To find the diameter of a driven pulley, multiply the diameter of the 

 driver by its number of revolutions, and divide the product by the number 

 of revolutions the driven pulley should go. The result will be the diameter 

 of the driven pulley. 



Example. Diameter. of pulley on the engine, 40 inches; speed of 

 engine, 160 revolutions ; speed in main shaft, 200 revolutions : 4n v l^u, 

 H-200^.32, which is the diameter in inches reauired for the dr'ven pullev. 

 To find the required size of a driving pulley, multiply the diameter of 

 the driven pulley by the number of revolutions it should make, and divide 

 the product by the revolutions of the driver. 



Example. Diameter of the pulley in intermediate is. four inches, 

 which is required to run 900 revolutions per minute. Revolutions of 

 shaft 200. 4X900h-200=18, which is the diameter in inches o-" the rul- 

 ley required to drive the intermediate at proper speed'. 



To find the length of belt for any two pulleys, add the diameter of the 

 two pulleys together^ divide this sum by 2, and multiply the quotient by 

 3i. Add the product to twice the distance b^t\vron the centres of shaft- 

 ing, and the result will be the required length of belt-.. 



