A.temperature and pressure B.humidity and temperature C.pressure and vacuum D.pressure and humidity
单项选择题A centrifugal pump attempting to develop flow against a closed discharge valve has a an ().
A.capacity of 0% B.efficiency of 100% C.internal slippage of 0% D.shut off horsepower rating of 100%
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