单项选择题
A.suppressant additive B.dispersant additive C.extreme pressure additive D.viscosity improver additive
The suction - force principle of operation is a typical...
单项选择题The suction - force principle of operation is a typical characteristic of （）.
A.centrifugal pumps B.jet pumps C.propeller pumps D.reciprocating pumps
Air leakage between the shaft and stuffing box packing ...
单项选择题Air leakage between the shaft and stuffing box packing in a centrifugal pump is prevented by （）.
A.a compressed packing gland B.lantern tings between the packing rings C.a liquid seal D.the stuffing box gland
Tube leaks in the distillate cooler of a two stage flas...
单项选择题Tube leaks in the distillate cooler of a two stage flash evaporator will result in （）.
A.loss of second stage vacuum B.contamination of the distillate C.lower feed inlet temperature D.contamination of the second stage condenser
