Auxiliary Machinery. Test 74 – Online Maritime Tests

Suppose the delivery air pressure of this compressor is 30.0 bar. What class of compressor could this be ?

An instrument air compressor.
A service air compressor.
A starting air compressor.
A working air compressor.

When ordering an expansion valve for a refrigeration system which of the following information is necessary ?

Pressure and temperature.
Size, tonnage, temperature and pressure.
Size and pressure.
Size and tonnage.

High latent heat is desirable in a refrigerant so that _____

smaller pipes can be used.
it will boil at low temperature.
a small amount of refrigerant will absorb a large amount of heat.
smaller compressors can be used.

This drawing indicates the timing of the unloader and drains of a compressor. After how many seconds will the compressor pump at full capacity ?

Between 7 and 12 seconds.
7 seconds.
12 seconds.
14 seconds.

If we shift the nozzle/flapper assembly to the left so that the length of 'a' is half of length 'b', to what level will L' rise before it stabilizes ?

Half the height from Level L.
Twice the height from level L.
Four times the height from level L.
1/4th the height from level L.

When is manual by-pass valve of this compressor cooler 'CW' operated?

When the compressor is new/overhauled with new rings.
During normal running to keep the temperature constant.
In cold climates to avoid moisture.
In the case of a cooler tube leaking.

What is 'simmer' in a safety valve ?

A metallic hammering noise.
A hissing sound indicating that a safety valve is leaking.
First leakage before the valve opens.
A failure of a safety valve to re-seat.

If the compressor discharge in a refrigeration system becomes frosted, the probable cause is _____

the refrigerant flooding back.
the compressor cuts out too frequently.
the expansion valve being improperly set.
a faulty king valve.

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