Description  Claims  Drawing  Cited references 

WO0075258A1   [0003] 
US2005242323A1   [0003] 
US4755316A   [0020] 
US4971712A   [0020] 
US4975212A   [0020] 
US5008028A   [0020] 

Fluorocarbon Refrigerants Handbook   [0020] 
Study of Lubricant Circulation in HVAC Systems   [0028]