单项选择题
A.either all the way open or all the way closed B.normally open C.throttled depending on load D.controlled by suction pressure
When a hydraulic vane pump is working, which of the fol...
When a hydraulic vane pump is working, which of the following is in contact with the vanes?（） (1) the rotor (2) the internal surface of the housing (3) the external surface of the housing
A.(1) only B.(2) only C.(1) and (2) D.(1), (2) and (3)
Which of the following items is necessary for all waste...
单项选择题Which of the following items is necessary for all waste heat boiler installations, regardless of design or manufacturer? （）
A.Control of evaporation B.A separate means to prevent feed-water contamination C.Power circulating pump D.Super-heater
Prior to lighting off a cold automatically fired auxili...
单项选择题Prior to lighting off a cold automatically fired auxiliary boiler, yon should （）.
A.check and regulate the water level B.close the air cock once fires are lit C.blowdown the gage glass D.crack the steam stop to assure protective steam flow
