A centrifugal pump attempting to develop flow against a……

单项选择题Condensate formed within the first-effect tube nest of a double-effect,low pressure evaporator, is removed by a （）.

A.series of baffles
B.crossover pipe
C.condensate separator
D.drain pump

单项选择题The temperature of a refrigerant gas is the highest （）.

A.at the compressor discharge
B.at the compressor suction
C.in the expansion valve
D.in the receiver

单项选择题Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?（）

A.Pressure-reducing valve
B.Unloading valve
C.Counterbalance valve
D.Pressure-relief valve

单项选择题If a centrifugal bilge pump were continually operated with the discharge valve closed the （）.

A.motor overload would open
B.relief valve would open
C.pump would eventually overheat
D.motor would overheat

单项选择题In order to accurately measure very low pressures, which of the instruments listed should be used?（）

A.Compound gage
B.Bonrdon tube
C.Manometer
D.Deadweight gage