PAPERS ON PHYSICS 



309 



EFFICIENCY TESTS OF THE NEW CENCO-HYVAC 

 OIL VACUUM PUMPS 



Prof. Chas. T. Knipp and C. S. Palmer 

 University of Illinois 



The Department of Physics at the University of IlHnois 

 has been interested in high vacuum work for a number of 

 years. The new types of mercury vapor condensation 

 pumps that are now generally used in the production of 

 exceedingly high vacua require supporting pumps that will 

 drav/ a fairly high vacuum of, say, .01 to .001 mm. of mer- 

 cury, and maintain it after weeks and months of continued 

 use. Such pumps, if moderately priced, are much in demand 

 at the present time. 



Last December, at our request, the Central Scientific 

 Company of Chicago sent one of their new design Cenco- 



Copillary 

 Valve 



Cenco H^VQC 

 Pump 



FIG. 1. 

 Hyvac oil pumps to our laboratory 

 for speed and endurance 



We wished to test it 

 It was inconvenient at the time 



