A.tightened up
B.sealed up
C.opened up
D.unscrewed
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A.use
B.release
C.protect
D.effect
A.paved
B.cleaned
C.welded
D.dismantled
A.water
B.oil
C.heat
D.steam
A.safety valve
B.blow down valve
C.scum valve
D.feed check valve
A.strainers
B.valves
C.elements
D.separators
最新試題
Which of the listed pumps is NOT a positive displacement pump?（）
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
Which of the following statements is correct concerning heat transfer?（）
The output volume of a positive fixed displacement pump can be changed only by （）.
A salinity indicator is used to determine the （）.
A salinity indicator is used to determine the （）.
The usual symptoms of cavitation in a centrifugal pump is （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.