单项选择题
A.centrifugal pump is cheaper than reciprocating pump
B.the size of centrifugal pump with same capacity is smaller than that of reciprocating pump
C.centrifugal pump makes maintenance easier than reciprocating pump does
D.all of the above
单项选择题 When a sudden increase in steam demand occurs from the boiler, the water level in the drum at the higher pressure will（）
单项选择题 Continuous surging of turbocharger can be caused by（） ①crash stop of engine ②increased back pressure after T-Ch ③fouled or damaged turbine nozzle ring
单项选择题 When occurring a fire in the scavenge air box, the following measures should be taken except for（）