Auxiliary Machinery. Test 74 – Online Maritime Tests

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

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

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

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

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

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

High latent heat is desirable in a refrigerant so that _____

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

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

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

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

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

What is 'simmer' in a safety valve ?

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

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