单项选择题
A.between the suction and discharge
B.below the liquid supply
C.above the liquid supply
D.any of the above
单项选择题 Which of the following pumps are self-priming, and can deal with liquid from a level below the pump? （） (1) reciprocating (2) vane (3) gear
单项选择题 Which of the following pumps are self-priming, and can deal with liquid from a level below the pump? （） (1) reciprocating (2) rotary (3) centrifugal
单项选择题 A positive displacement pump is that where the volume of the pump chamber is alternately （） to draw the liquid in and then （） to force the liquid out.