WASHING AND STERILIZING 87 



their high cost, which renders their use by small dairy- 

 men almost prohibitive. 



Sterilizer Designed by the Author. After consid- 

 erable study and experimentation, the author succeeded 

 in constructing a simple and efficient concrete sterilizer 

 whose low cost puts it within reach of all dairymen. A 

 section through this sterilizer is shown in Fig. 39. 



Essentially, it is a rectangular concrete tank with a 

 wooden cover which is lined with zinc. The sides and 

 bottom are five inches thick and are built of concrete, 

 which is made up of one part cement, two parts sand, 

 and two parts coarse gravel. A thin coat, consisting 

 of one part cement and two parts sand, is used as an 

 inside finish. A piece of 2x4-inch studding is placed 

 around the top of the tank and is secured by six one-half- 

 inch iron rods two feet long, embedded in the concrete 

 walls, one being placed at each corner and one on either 

 side midway between the corners. This arrangement not 

 only strengthens the tank, but also makes the cover fit 

 tighter. 



The cover consists of two thicknesses of one and one- 

 eighth-inch tongued and grooved flooring three and one- 

 half inches wide. The upper boards run lengthwise and 

 the lower crosswise of the tank. The lower boards fit 

 into a shoulder projecting from the base of the 2x4-inch 

 studding. The entire inside portion of the cover is cov- 

 ered with zinc. To insure additional tightness of the 

 cover, a layer of asbestos is placed on top of the 2x4s. 

 A heavy weight attached to a one-half inch rope running 

 over a pulley fastened to the ceiling, raises the cover and 

 holds it open when desired. The cover is strengthened 

 by running three pieces of 2x4-inch studding cross-wise 

 of the tank, one at the middle and one at either end. The 



