FROM THE PRACTICAL VIEWPOINT 



hose against the outer surface of the pipes, after 

 the washing has been completed. It is well known 

 that steam when relieved of its pressure rapidly 

 cools, and a person can hold his hand a short 

 distance from an open steam pipe with no incon- 

 venience. It often happens that not all the parts 

 of the cooler receive the benefit of even this re- 

 duced temperature. The tubes, of course, must 

 be empty of the water usually contained in them 

 before they are steamed. 



It might be feasible to provide covers for these 

 coolers which would be sufficiently tight to allow 

 the pressure of the steam to be retained to some 

 extent before it escaped into the outer air. Some 

 covers are now made which are fairly tight. 



The best way to sterilize this form of cooler is 

 to have the tubes of sufficient strength so that 

 steam may be admitted on the inside under pres- 

 sure. In such case the sterilization is from the 

 inside. If, while the pipes are hot from the en- 

 closed steam, water is allowed to trickle over the 

 outside, this is heated, and is itself converted into 

 steam, which helps to cleanse the pipes. 



Care should be taken to be assured that the 

 steam which rises from the milk while being cooled 



159 



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