单项选择题
A.variable stroke pumps B.multistage pumps C.positive displacement pumps D.triple-ported pumps
The （） discharge a nearly constant amount of liquid reg...
单项选择题The （） discharge a nearly constant amount of liquid regardless of pressure.
A.mixed-flow pump B.axial-flow pump C.centrifugal pump D.displacement pump
Sediment collects in a tubular purifier （）.A.on top cov...
单项选择题Sediment collects in a tubular purifier （）.
A.on top cover B.on sides of bowl C.in drain line on the discs D.on the discs
In an oil cooler circulated by sea water, the oil is at...
单项选择题In an oil cooler circulated by sea water, the oil is at a larger pressure the result being that any leak in the cooler will mean a loss of （）.
A.oil B.sea water C.refrigerant D.fresh water
