Auxiliary Machinery. Test 12 – Online Maritime Tests

Which main unit determines the increasing/decreasing of the fuel quantity, i.e. controls 'the effective delivery stroke' (Bosch type pump)?

The fuel injector
The booster pump
The fuel master control valve
The governor

Most boiler design incorporate external 'downcomers'. For what purpose are those 'downcomers' primarely incorporated?

Ensure adequate circulation in all conditions of steaming.
Directional control of steam bubbles.
Provide extra support for furnace tubes.
To increase heating surface area.

You are going to start firing a boiler. Which of the below mentioned alternatives do you consider as most important?

Activating the main safety valves.
Opening the main steam pressure outlet valve.
A thorough ventilation of the combustion chamber before the ignition takes place.
Bottom-blowing the boiler to be absolutely convinced that water is present in the boiler.

Some 4-stroke engines are fitted with a rotorcap on the cylinder head valves. For what reason?

Distribute the exhaust gas or the air inlet better to improve combustion
Improve the scaling surface function, increase the service time of the exhaust valve in the engine
To prevent the valve spindle to stick.
Rotate the inlet valve during operation.

For what purpose is a 'de-aerator' in a boiler feed water system used?

Removal of excess sulphur in the feed water.
Removal of excess hydrogen in the feed water.
Removal of excess nitrogen in the feed water.
Removal of excess oxygen in the feed water.

Quality of the feed water in a steam plant changes during operation. Caused by this, the water is regularly tested. Which of the below statements describes the chemical mechanisms normally occuring?

Water is becoming sligthly less conductive and does not transfer heat.
Generation of carbonic acid causes the water quality to drift towards sour and lower the pH - number.
All of the mentioned alternatives.
Generation of sulphur acid causes the water quality to drift towards sweet and rise the pH - number.

What is the main purpose of bottom-blowing a boiler?

To control that water is present in the water chamber, when the boiler is in active operation.
To adjust steam pressure when the burner capacity is excessive.
To get rid of sludge in the water chamber.
To check that we do not have any leak of smoke and gases in the combustion camber.

An expansion process along a turbine venturi is ofthen recognized as if no heat transfer out of the system is occuring What is the correct term for this?

Isochorie.
Endothermic
Isobar.
Adiabatic.

Reduced capacity accompanied by vibration and noise at the suction of a centrifugal pump results from the action of vapor pockets in the fluid being pumped caused by:

Cavitation
Steam knock
Fluid friction
Water hammer

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