A.Closing of the solenoid valve
B.Closing of the expansion valve
C.An increase in the suction pressure
D.Decreasing the suction pressure
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A.When the helm is at any angle other than amidships
B.When the six-way valve is opened
C.When the ram relief valves lift
D.When the redder angle is different from the position of the helm
A.suppressant additive
B.dispersant additive
C.extreme pressure additive
D.viscosity improver additive
A.centrifugal pumps
B.jet pumps
C.propeller pumps
D.reciprocating pumps
A.a compressed packing gland
B.lantern tings between the packing rings
C.a liquid seal
D.the stuffing box gland
A.loss of second stage vacuum
B.contamination of the distillate
C.lower feed inlet temperature
D.contamination of the second stage condenser
A.total head
B.discharge head
C.net positive suction head
D.suction head
A.slide block
B.tilting box
C.pintle
D.reaction ring
A.Liquids with different viscosities will always have the same specific gravity
B.Liquids with different viscosities will never have the same specific gravity
C.Viscosity and specific gravity are directly proportional
D.Viscosity and specific gravity are not related in that one does not define or limit the other
A.stored at temperatures below 60 degrees Fahrenheit
B.charged into a system having copper fittings
C.allowed to mix with compressor oil
D.exposed to an open flame or hot surface
A.acid formation
B.sludge formation
C.ice in the expansion valve
D.All of the above
最新试题
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
Which of the listed pumps is NOT a positive displacement pump?（）
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
Thermostatic expansion valves can be adjusted for （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
The output volume of a positive fixed displacement pump can be changed only by （）.
A pressure drop through the refrigerant liquid line may cause （）.
The usual symptoms of cavitation in a centrifugal pump is （）.