A centrifugal bilge pump requires priming （）.
A. primarily to lubricate the shaft seals
B. due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller
C. to initially unload the pump by having its head pressure equal to discharge pressure
D. in order to overcome the potential energy of water in the discharge line
微信支付 
支付宝支付