In which of the listed refrigeration system components does superheating of the refrigerant take place?（）

单项选择题Excessive lube oil consumption by a reciprocating air compressor can be caused by （）.

A.using a slightly dirty air filter
B.using oil having an excessive viscosity
C.intercooler or after-cooler leaks
D.carrying the oil level higher than normal

单项选择题The effect of high vapor superheat in a refrigeration system, is a an （）.

A.increased capacity of the compressor
B.more efficient operation of the thermal expansion valve
C.decreased capacity of the compressor
D.loss of receiver capacity

单项选择题A dirty intercooler on an air compressor will cause （）.

A.damage to the un-loader operating diaphragm
B.an increase in current flow to the motor
C.high pressure in the receiver and filter
D.an excessive consumption of crankcase oil

单项选择题Under normal operating conditions, the highest temperature and pressure conditions existing in a flash-type evaporator will occur in the （）.

A.first stage
B.second stage
C.distillate cooler
D.salt water feed heater

单项选择题Which of the listed conditions will cause the feed water that has not flashed to vapor in the first-stage of a flash evaporator, to flow into the second-stage?（）

A.Gravity siphon effect
B.Higher vacuum in the second-stage
C.Difference in brine density between first and second stages
D.lower pressure in first-stage