Auxiliary Machinery. Test 3 – Online Maritime Tests

On a two stage compressor you will find pistons with different diameters (one is bigger than the other).Which one of the following statements is correct ?

The biggest diameter piston is the stage two piston.
The smallest diameter piston is the stage two piston.
A big piston will deliver dryer air into stage one.
A big piston will give less oil content in the air.

The safety valve on a steam boiler shall:

Block the spring and the valve so no steam is escaping in the funnel, if the spring on the valve is not working properly.
Open, when pressure in the boiler is in excess of normal working pressure.
Be used to regulate the the steam pressure.
Be adjusted by the crew when necessary.

What do you think would be the most likely cause of high discharge pressure from a freon compressor?

Broken discharge valve plate.
Broken suction valve plate.
Blocked condenser.
Too little gas in the system.

The cargo hold air-circulating system normally permits 2 speeds ( 45 and 90) air-changes on the cargo hold air fans. Which air-speed will You use when You carry banana cargo?

90 air-changes.
The air should not be changed.
45 air-changes.
Not important.

What do you think would be the most likely cause of too low suction pressure in a freon compressor?

Blocked condenser.
Broken suction valve plate.
Too little gas in the system.
Blocked condenser tubes.

The thermoexpansion-valve is a part of the refrigeration system. What is the thermo-expansion-valve doing?

Regulating cooling water temperature.
Regulating the cargo hold temperature.
Regulating freon liquid flow to the evaporator.
Regulating the suction pressure.

Which cleaning agents for machinery space are important to use due to the oily water separators function?

Any kind of chemicals.
An emulsification agent.
A non-emulsifying agent with self splitting emulsifiers.
No kind of chemicals.

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