52 



AIR COMPRESSORS 



Approximate data on the 10|-in., cross-compound, air com- 

 pressor showing capacity, steam consumption, volumetric 

 efficiency, displacement, steam pressures for operating at 

 constant speed with various air pressures, and steam pressures 



'acemenf- Cu.f/. wrM/nl- 



4O 60 80 100 120 140 16O 



PIG. 1 



for operating against constant air pressure at various speeds 

 are shown in the charts given in Figs. 1 and 2. The first 

 chart shows that at a constant speed of 130 single strokes 

 per min. and 80 Ib. air pressure, the steam pressure required 



