单项选择题
A.The liquid receiver functions to collect and remove non-condensable gases
B.A thermostatic expansion valve is used to control refrigerated space temperature
C.Refrigerant temperature in an evaporator is directly related to refrigerant pressure
D.Dehydrators must be used continuously in a refrigeration system
单项选择题 The basic function of the centrifugal pump impeller is to （）.
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 （）.