Marine Refrigeration, Cargo Ventilation, Noise, and Vibrations Questions Bank

In this post you will get an insight of what type of
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.

Questions related to Marine refrigeration and A.C plant

Q1:         Make a
sketch of simple refrigeration circuit and describe the operation of circuit.
Q2:         Make a line
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.
Q3:         Sketch and
label a thermostatic expansion valve as fitted to a vapor compression
refrigeration system and explain its operation.
Q4:         State the
desirable properties of refrigerant and how these influence the design of
Q5:         State the
function of following devices fitted on the refrigeration system:
High pressure cut out switch
Magnetic liquid stop valve
Oil pressure switch
Low pressure cut out switch
Oil separator
Q6:         Explain
what is meant by short cycling, describe a halide torch and how is it used for
leak detection in refrigeration system?
Q7:         State under
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
enthalpy curve.
Q8:         Sketch a
typical domestic refrigeration plant with control for automatic operation and
describe it. State specific temperature maintained in different rooms.
Q9:         What is air
conditioning? Sketch and describe a single duct system.
Q10:       What is
relative humidity? How is it calculated? State the typical comfort condition.
How can it be achieved in summer & winter?
Q11:       Give causes
for the following troubles in air conditioning plant:
Compressor short cycles
Discharge pressure too high
Suction pressure too high
Compressor fails to start
System short of capacity

Questions related to cargo ventilation and axial flow compressors

Q1:         Discuss the
necessity of shipboard ventilation? Explain low and high velocity system and
their relative merits?
Q2:         Describe a
suitable ventilation plant for ship’s engine room and explain the air
distribution arrangement.
Q3:         Write a
note on modern techniques of ship’s engine room ventilation.
Q4:         Explain the
purpose of ship’s cargo hold ventilation. What methods are used for it?
Q5:         Describe
with sketches the arrangement of ventilating
Living spaces
Sanitary spaces
Dining saloon
Working space of ship
Q6:         Explain the
general principles of operation of fan. State the fundamental fan laws &
distinguish between various types of fans.
Q7:         Sketch and
describe the construction of a centrifugal blower used on air handling units of
ships AC plant?
Q8:         Sketch
& describe a centrifugal fan used in turbocharger of a marine diesel
Q9:         Sketch and
describe an axial flow compressor used as exhaust blower in pump room of an oil
Q10:       Write short
notes on:
Mach number
Pre whirl vanes
Characteristic curve of centrifugal blower
Backward swept, radial tipped & forward swept blades/

Question related to Noise and vibrations

Q1:         What are
the sources of noise on ship and describe the methods to suppress it?
Q2:         What is the
unit of sound and how can it be measured?
Q3:         What are
the detrimental effects of noise on human body? How one can protect himself
from ill effects of noise on ship?
Q4:         Can noise
be used as a useful parameter? Justify your answer with suitable explanation.
Q5:         What is the
mechanism of noise production and its behavior in enclosed spaces>
Q6:         What is
vibration and how is it caused on ships? Describe various forms of mechanical
Q7:         What is
resonance? How are hull vibration caused?
Q8:         What is
meant by critical speed and barred speed range? What is it’s effect on torsinal
Q9:         What are
dampers and detunes and how they reduce vibrations?
Q10:       What is a
torsiograph, how it works and what is its use on ship?

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Mark Eriscson

Love to write about topics related to maritime sector. Was born in sailor's family, so love to ride on those high seas. In free time i would like to go for a good sunbath and some soothing guitar music. Want to have my own boat one day.

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