单项选择题
A.Impeller B.Electric motor C.Volute D.Eye
Excessive circulation of the lubricating oil with the r...
单项选择题Excessive circulation of the lubricating oil with the refrigerant in a refrigeration system will cause （）.
A.carbon deposits on the compressor suction valves B.the evaporator temperature to increase C.rapid corrosion of the thermal expansion valve D.no operating problems
Scale accumulation on evaporator heat exchange surfaces...
单项选择题Scale accumulation on evaporator heat exchange surfaces （）.
A.increases brine density B.increases distillate salinity C.reduces metal corrosion D.reduces heat transfer
In order to properly remove air from the casing of a ce...
单项选择题In order to properly remove air from the casing of a centrifugal pump when starting, the pump should have a （）.
A.positive head B.negative suction head C.mechanical seal D.vent valve attached to the casing at the top of the volute
