198 CRBAMEttY BUTTER MAKING 



. 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 2x45. 

 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 crosswise 

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

 hinges by which the cover is fastened are attached to 

 these 2x45, as shown in Fig. 50. 



A safety valve, set at ten pounds pressure, is inserted 

 through the top of the cover at the most convenient place. 

 A bell trap (see Fig. 41) placed in the bottom of the 

 sterilizer serves as an outlet for the condensed steam. 



The steam is admitted either through the sides or 

 through the bottom of the sterilizer, and both inlet and 

 outlet pipes should be laid in the concrete at the time the 

 sterilizer is being built. 



A false, perforated metallic bottom is placed one inch 

 from the bottom of the sterilizer, on which all vessels are 

 placed in an inverted position. 



The following is an itemized statement of the cost of 

 the material used in the construction of this sterilizer, 

 whose inside dimensions are: length, 7 1-3 feet; width, 

 2 1-4 feet; depth, 2 1-3 feet. 



