Mech Sys Ops

Question 1

What is the desired temp a calorifier is maintained at?

Answer 1

66 Degrees C

Question 2

How is the adjustment carried out on a Hot Water Calorifier?

Answer 2

Bimetallic strip, using appropriate tools

Question 3

What state the following of a boost pump in a RO plant:
- location
- function
-operating parameters

Answer 3

supply water to HP pump
1 bar
before pre-filters

Question 4

What state the following of a HP pump in a RO plant:
- location
- function
-operating parameters

Answer 4

increases pressure to

Question 5

What are the uses of demon water?

Answer 5

• gas turbine wash
• helicopter engine wash
• medical use
• WE cooling systems
• Chilled water systems
• Diesel coolant systems

Question 6

what are the uses of fresh water?

Answer 6

• drinking water
• upper decks wash down
• laundry
• bathroom/heads
• galley
• gas turbine wash
• fuel sep
• mess decks
• weapon mag space
• technical water RO plant

Question 7

what is the purpose of a conductivity meter?

Answer 7

to give a visual indication of the presence of salt in the sea, potable and technical water of a certain engine room

Question 8

describe how a conductivity meter works

Answer 8

• two electrodes are placed at a predetermined distance apart in feed water system
• current is applied in series with a lamp
• the fresh water being high resistance, allows only a min current to flow
• the presents of salt in water reduces resistance, between the two, increasing the current

Question 9

what three factors determine the current flow between the electrodes?

Answer 9

• distance between the electrodes
• the amount of salt in the water
• the temperature of the water

Question 10

how do you clean the electrode probes?

Answer 10

• isolate
• disconnect probe
• scrub nylon brush, 50;50 solution
• rinse and refit

Question 11

What is the standard of quality of water in the RN?

Answer 11

fresh water - 250-300 ppm
demon water- 2.5-25ppm

Question 12

what is meant by super chlorination?

Answer 12

the process of sterilisation of FW systems using extremely high dose of chlorine

Question 13

when is super chlorination done?

Answer 13

• on commissioning
• after the cleaning or re-coating internal surface of fresh water tank
• • when is it considered necessary

Question 14

what formula is used to determine amount of chlorine used for super chlorintion?

Answer 14

D= c/1000 x 100/A x V

D= chlorine
C= initial require amount of chlorine
A= % of chlorine in compound
V= volume of water

Question 15

list the steps taken to minimise contamination and stagnation in fresh water systems on board

Answer 15

• swapping tanks every 24 hours
• aerator
• chlorine
• non-return valves
• lockable sounding tube caps
• leak off lines
• air escape tubes
• no dead legs

Question 16

what is looked for when inspecting plumbing?

Answer 16

• physical damage
• vibration damage
• noise shorts

Question 17

give a brief description of osmosis

Answer 17

natural process where a solution of low concentrate flows through a semi-permeable membrane to dilute of high concentration. this will continue till equilibrium

Question 18

give a brief description of reverse osmosis

Answer 18

reverse of osmosis, by adding sufficient pressure to the salt solution to over come osmotic pressure head.
level of pure water will increase leaving the salt solution a high concentrate.
process removes, 90-99% of TDS and bacteria.
must be chlorinated before it is fit for human consumption.

Question 19

state hazards and safety precautions of an RO Plant

Answer 19

High Voltage Electrical hazard
- 440v
- ensure supplies to both pump motor and control system are isolated
- tag out carried out

High Pressure Hazard
- do not work on pressurised systems
- security of fixtures and fittings
- check for correct operation

Chemical Hazard
- correct PPE
- avoid spillages and skin contact
- haz data sheets available

Question 20

main courses of damage to PALL DT modules

Answer 20

• incorrect torque setting
• pressure on permeate discharge line
• vaccum

Question 21

the definition of a mount

Answer 21

to minimise radiated and self noise to improve habitlility and reduce damage to equipment.

Question 22

what are the reasons for mounting?

Answer 22

• provide vibration isolation between equipment and the ships structure
• reduces levels of vibrations transmitted through to the ships structure to minimise self noise
  -controlled flexibility

Question 23

what are the different types of mounts?

Answer 23

x mount
j mount
PD mount
L mount
M mount

Question 24

what is the application of a PD Mount?

Answer 24

PD mount is a general purpose resilient mount for heavy equipment. it is not fully captive design and thus be fitted with accelerators and decelerators