CENTRIFUGAL SEPARATION 



87 



when empty and when loaded. The state of repair and kind of 

 oil used and efficiency of oiling are further factors which bear 

 on the ease of running. 



Factory separators of a capacity about 5000 pounds per hour, 

 when loaded require about 2 H. P. at the start and until full speed 

 is attained. After that, from seven-eighths to one H. P. is suffi- 

 cient to maintain full speed. Farm separators of the usual capa- 

 city of about 350 to 500 pounds per hour require approximately 

 from .063 to .16 H. P. when loaded. Lamson 1 determined the 

 relative Horse power required of twelve different farm separa- 

 tors, when empty and when loaded. He used for his determina- 

 tions a Torsion dynamometer, designed, built and perfected at 

 Purdue University, but instead of running milk through the 

 separator in his trials with the loaded machine, he used salt brine, 

 having a specific gravity of 1.032 at 60 F. His results are shown 

 in table 5. 



Table 5. Horse Power Required to Drive Empty and Loaded 



Farm Cream Separators and Ratio of Power Required to 



Drive Empty to that of Loaded Separators. 



1 Lamson. A Study of Farm Separators. M. S. A. Thesis, Purdue Uni- 

 versity, 1918. 



