单项选择题
An orifice-check valve placed in a hydraulic system is used to（）
A.regulate the fluid flow in either direction
B.restrict movement of hydraulic fluid in one direction, but allow free movement in the other direction
C.allow free movement of hydraulic fluid in both directions
D.allow a restricted fluid flow in one direction only
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相关考题
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单项选择题
Purging air from a hydraulic system is necessary when（）
A.adding small amounts of oil to the system
B.the system has been overheated
C.the system has been drained and then filled with new oil
D.the system has been idle for a long period of time -
单项选择题
Leakage of hydraulic fluid from around the shaft of a hydraulic motor may be caused by（）
A.permanent loss of pump suction
B.worn shaft seals
C.high level in the oil sump
D.low motor RPM -
单项选择题
Air trapped in the hydraulic fluid of a steering system would be indicated by（）
A.an improper rudder response
B.hammering noises in the equipment or transmission lines
C.popping or sputtering noises
D.all the above
