In its simplest form the pressure reducing valve is opened or closed by () which is balanced by the downstream pressure acting on a diaphragm.
A. adjusting a nut
B. a pre-tensioned spring
C. any spring
D. upstream pressure
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机车顶车时,()不连环顶车。
A. 允许
B. 严禁
C. 可以
D. 可慢速
降低修理费用的错误做法是()。
A. 提高船速
B. 加强自修保养工作
C. 延长船舶进坞间隔期
D. 减少厂修工作量
液压系统共有几个过热指示灯()
A. 1个
B. 2个
C. 3个
D. 4个