62 Testing Milk and Its Products. 



also to prevent what may be serious accidents from 

 a general smash up, if the turbine "runs wild" by 

 turning on too much steam. The revolving wheel of the 

 tester should be made of wrought or malleable iron, or of 

 wire, so that it will not be broken by the centrifugal 

 force, thus avoiding serious accidents. The swinging 

 pockets which hold the test bottles in some machines, 

 should be so made that the bottles will not strike the 

 center of the revolving frame when in a horizontal posi- 

 tion. Tests have often been lost by the end of the neck 

 catching at the center, the bottles thus failing to take an 

 upright position when the whirling stops. 



71. The exhaust steam pipe of turbine testers should 

 not have too many turns in it or be much reduced in size 

 from that of the opening in the tester. A free escape of 

 the exhaust steam is necessary to prevent the steam col- 

 lecting in the test bottle chamber and overheating the 

 test bottle when whirled (41). 



The cover of the tester should have an opening in it 

 which is provided with a sliding damper or some arrange- 

 ment by which this opening can be closed when desired. 

 If whole milk or cream is being tested, this hole in the 

 cover should be open so that a draft of air may enter the 

 test bottle chamber during whirling, and force the steam 

 out of the bottle chamber into the exhaust pipe. If skim 

 milk is being tested, all openings in the cover should be 

 closed. This shuts off the draft of air, and the exhaust 

 steam heats the test bottles during whirling to 200 F. in 

 some cases. This high temperature aids in separating 

 the last traces of fat in skim milk and gives a most accu- 

 rate test of samples containing less than one-tenth per 



