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单选题
As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into （）.
A
liquid
B
oily mixture
C
emulsion
D
vapor
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all refrigerant must be pumped into the receiver before adjustments are madeC
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单选题In a compression refrigeration plant the refrigerant flows from the expansion valve and through the （） where it absorbs heat from the space being cooled and becomes a gas or vapor.A
compressorB
condenserC
throttle valveD
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单选题A ruptured diaphragm in a thermostatic expansion valve will cause the valve to （）.A
openB
closeC
remain in its positionD
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solenoid valve to seizeB
compressor to huntC
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单选题The only means of removing the latent heat of condensation from a refrigerant in the normal refrigeration cycle is by （）.A
passing it through the expansion valveB
condensing refrigerant in the system condenserC
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maintaining a high pressure on the systems receiver
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单选题The compressed air is admitted to each cylinder through a cam operated by starting air valve when the piston has just passed its （）.A
BDCB
TDCC
BBDCD
ATDC
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单选题After passing through the expansion valve the refrigerant should be in the state of （）.A
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单选题The principal purpose of sub-cooling liquid refrigerant prior to its entering the expansion valve is to （）.A
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The solenoid valves directs high pressure gas to the underside of the unloading piston, causing it to rise and allowing the recirculating ports to be openedC
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adjusting a nutB
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The diesel oil must never be allowed to mix with the heavy fuelB
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The heating steam to the pre-heater should be secured as soon as the diesel fuel passes through the three-way valveD
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