A.A gate valve
B.A globe valve
C.Any check valve
D.Any needle valve
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A.a shortage of compressor oil
B.warm food in the refrigerator
C.excessive condenser cooling water
D.a shortage of refrigerant
A.molecular fluid vibration
B.energy losses
C.wide pressure variations
D.mechanical damage to control valves
A.Keeps the refrigerated space cooler
B.Reduces the efficiency of the plant
C.Takes the load off the compressor
D.Has no affect on the system
A.proportional band
B.the error signal
C.the reset signal
D.feedback
A.Dehydrators must be used continuously in a refrigeration system
B.A 25 ton refrigeration system has the same cooling effect as melting 25 tons of ice in 24 hours
C.A thermostatic expansion valve is used to control refrigerated space temperature
D.The liquid receiver functions to collect and remove non- condensable gases
最新試題
If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）
One cause of high head pressure occurring in a refrigeration system can be （）.
Thermostatic expansion valves can be adjusted for （）.
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 （）.
The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.