A spur gear pump should be operated with the discharge valves （）.

A.increase speed
B.increase the size of the cardent assembly
C.reduce wearing ring clearances
D.change the pump to a "close coupled" arrangement

A.Chemical energy
B.Mechanical energy
C.Thermal energy
D.Electrical energy

A.air bubbles in the sight glass
B.any leaks in the system
C.over-travel in the rudder angle indicator
D.lost motion in the rams