A.gate valve
B.globe valve
C.check valve
D.plug cock
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A.At the designed operating temperature, the liquid refrigerant charge has changed to a vapor
B.The liquid refrigerant tends to collect at the bellows or diaphragm and reduces the valve sensitivity
C.The sensing bulb is empty of liquid refrigerant charge at the designed operating temperature
D.The sensing bulb is never emptied of liquid refrigerant under normal operating conditions
A.diaphragm type gage
B.pressure transducer
C.manometer
D.All of the above
A.reduce radial thrust to the impeller
B.double the liquid velocity through the pump when compared to a single volute
C.reduce hydraulic end thrust
D.provide the effect of multi-staging
A.dirt will cause corrosion of bearing
B.bearings will leak oil excessively
C.dirt is very abrasive when mixed with grease
D.grease will become inflammable
A.promote refrigerant dehydration
B.be absorbed in the receiver
C.cause low condensing pressure
D.carry moisture and lead to corrosion
最新試題
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
The major source of chemical contaminants in hydraulic fluid is （）.
Thermostatic expansion valves can be adjusted for （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
A pressure drop through the refrigerant liquid line may cause （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）