单项选择题
A.directly increase the pressure of the liquid being pumped
B.directly increase the velocity of the liquid being pumped
C.convert the potential energy of the liquid to kinetic energy
D.separate air from the liquid being pumped
单项选择题 Excessive oil foaming in the crankcase of a refrigeration compressor can result in （）.
单项选择题 The centrifugal pump component responsible for converting the mechanical energy of the liquid being pumped, to that of kinetic energy is the （）.
单项选择题 In a refrigeration system, foaming of the crankcase oil may cause the （）.