单项选择题
A.mechanical energy B.heat energy C.potential energy D.kinetic head
A centrifugal impeller consists of a number of vanes cu...
单项选择题A centrifugal impeller consists of a number of vanes curving （） from the direction of rotation.
A.backwards B.forwards C.upward D.downwards
When installed for bilge pumping or ballast duty, centr...
单项选择题When installed for bilge pumping or ballast duty, centrifugal pumps require a （） to remove air from the suction pipe.
A.air chamber B.head lank C.primer D.prime mover
Water enters the rotating impeller through the entry, k...
单项选择题Water enters the rotating impeller through the entry, known as “（）”, at the centre.
A.eye B.hole C.balance holes D.opening
