questions that are asked in the marine refrigeration, cargo ventilation, noise,
and vibrations. It will prove beneficial for the exams and if you are sitting
for an interview in the shipping company.
sketch of simple refrigeration circuit and describe the operation of circuit.
diagram of a Freon – 22 refrigeration circuit showing the relative position of
the main components in the system and the direction of flow in all lines.
label a thermostatic expansion valve as fitted to a vapor compression
refrigeration system and explain its operation.
desirable properties of refrigerant and how these influence the design of
function of following devices fitted on the refrigeration system:
what is meant by short cycling, describe a halide torch and how is it used for
leak detection in refrigeration system?
cooling and super heating, where these take place in a refrigeration plant.
Describe their effect on the efficiency of plant and show them on pressure
typical domestic refrigeration plant with control for automatic operation and
describe it. State specific temperature maintained in different rooms.
conditioning? Sketch and describe a single duct system.
relative humidity? How is it calculated? State the typical comfort condition.
How can it be achieved in summer & winter?
for the following troubles in air conditioning plant:
Questions related to cargo ventilation and axial flow compressors
necessity of shipboard ventilation? Explain low and high velocity system and
their relative merits?
suitable ventilation plant for ship’s engine room and explain the air
note on modern techniques of ship’s engine room ventilation.
purpose of ship’s cargo hold ventilation. What methods are used for it?
with sketches the arrangement of ventilating
general principles of operation of fan. State the fundamental fan laws &
distinguish between various types of fans.
describe the construction of a centrifugal blower used on air handling units of
ships AC plant?
& describe a centrifugal fan used in turbocharger of a marine diesel
describe an axial flow compressor used as exhaust blower in pump room of an oil
Question related to Noise and vibrations
the sources of noise on ship and describe the methods to suppress it?
unit of sound and how can it be measured?
the detrimental effects of noise on human body? How one can protect himself
from ill effects of noise on ship?
be used as a useful parameter? Justify your answer with suitable explanation.
mechanism of noise production and its behavior in enclosed spaces>
vibration and how is it caused on ships? Describe various forms of mechanical
resonance? How are hull vibration caused?
meant by critical speed and barred speed range? What is it’s effect on torsinal
dampers and detunes and how they reduce vibrations?
torsiograph, how it works and what is its use on ship?