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
单项选择题 Tube leaks in the distillate cooler of a two stage flash evaporator will result in （）.
单项选择题 The pressure of a liquid leaving the pump can be referred to as the （）.
单项选择题 The delivery rate of a variable stroke axial piston hydraulic pump is controlled by varying the position of the （）.
