=221. Care of Dryers.= Dryers should be kept clean. They should not be heated enough to cook the food. Set them in a dry, airy place. CHAPTER XXXI SEPARATORS AND EMULSIFIERS =222. Cream Separators.= A cream separator is a device for separating cream from milk. Separation can be done best while the milk is still warm (Fig. 124). Separators should be set in a bright, dry, airy place free from dust and dirt. Near the separator should be a convenient place for airing and sunning the tin parts which come in contact with the milk. The base for the separator should be solid enough so that it will not shake while the machine is being operated. If set on a wooden floor, see that the boards are nailed in place, and if the floor is thin, put heavy strips to cover several boards across it. Fasten the strips firmly to the floor and set the separator on them. When the machine is set up, be sure that it is set level. =223. Different Types of Separators.= There are two types of separators--one which contains discs of metal (Fig. 125), and the other which depends upon a cylinder in which the milk rotates (Fig. 124) for the separation of the cream from the skim milk. Fig. 126 shows a sectional view of the DeLaval separator. Cream is lighter than milk, and when milk and cream are whirled rapidly, the milk, being heavier, flies to the outside of the container, and the cream stays near the center. Two pails whirled rapidly made the first separator ever used, but that was clumsy and impractical. Modern separators consist of a pan which holds the milk, and which lets it flow in a stream into the portion of the machine which is being whirled rapidly by the turning of the wheel at the side. There is a place in the rotating part which lets the cream flow from the center into one container, and the milk flow from the outside to another. [Illustration: FIG. 124. Cream separator.] The parts of the machine must be fitted together properly; otherwise, it will fail to do good work. Always turn the wheel at the speed indicated for the machine with discs. If there is no speed indicated, turn as fast as needed for good separation of milk and cream. Take care not to drop and dent any of the tin parts. Adjust for the density desired for the cream. [Illustration: FIG. 125. Discs in DeLaval cream separator.] =224. Washing the Machine.= As soon as milk has been skimmed with the separator, pour some water into the bowl and run it thru the separator the same as the milk. Wash the bowl and other parts in hot water in which washing soda has been dissolved. Rinse in clear water, and then scald with boiling water. Once a week give it a more thoro washing, scrubbing all parts with a brush. Sun the parts when not in use. =225. Oiling.= The mechanical parts which whirl the separator should be kept oiled. In oiling, follow the directions which come with the machine. Use a good grade of oil.