单项选择题
A.overheated compressor bearings B.excess lube oil viscosity C.carbon deposits on the compressor piston rings D.wax crystals forming in the lubricant
The centrifugal pump component responsible for converti...
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 （）.
A.electric motor B.volute C.impeller D.diffusion nozzle
In a refrigeration system, foaming of the crankcase oil...
单项选择题In a refrigeration system, foaming of the crankcase oil may cause the （）.
A.expansion valve to overfeed B.compressor to knock C.water regulating valve to fail D.crankcase drains to plug
Excessive scale formation in a distilling plant may res...
单项选择题Excessive scale formation in a distilling plant may result from （）.
A.poor distillate quality B.reduced evaporator capacity C.low brine concentration D.improper vacuum regulation
