Which of the following pumps will build up a bursting pressure or stall their motors if the discharge valves are closed?（） (1) gear (2) centrifugal (3) screw
A.（1）and（2） B.（1），（2）and（3） C.（1）and（3） D.（2）and（3）
A.providing the impeller with balancing holes B.the use of symmetrical impeller C.neither A nor B D.either A or B
A.throttling the pressure line B.changing the speed of the rotor C.either A or B D.None of the above is true
微信掃一掃關(guān)注公眾號后聯(lián)系客服
微信掃碼免費搜題
