HPSW and Cooling Systems

Question 1

What is the HPSW operating pressure?

Answer 1

7 bar (100psi-120psi)

Question 2

What is fitted to prevent system over pressurisation?

Answer 2

Relief valves and 10% leak off valves maintain the pressure at 7 bar.

Question 3

State six uses of HPSW.

Answer 3

Firefighting - hydrants/sprays/centre feed hose reels
Pre Wetting system
Fitted Bilge and Salvage Eductors
Emergency Cooling to main propulsion gas turbines/diesel generators
Auxilliary Machinery cooling water system
Making of fresh water

Question 4

Explain the flow of SW from the Sea to the Ringmain.

Answer 4

salt-water pump pulls through the sea cock then a strainer while discharging 10% through a discharge valve up through the riser then supplying the ringmain at 7 bar

Question 5

Explain the HPSW Ringmain.

Answer 5

The ringmain is a long multi-section of pipework that runs along 2 decks supplies multiple systems with salt-water throughout the ship such as the emergency cooling systems and pre wet

Question 6

How are the HPSW pumps driven and where can they be operated from?

Answer 6

The are driven electrically and are operated both locally and remotely

Question 7

Where will HPSW sprays be located?

Answer 7

Magazines
Paint lockers
Inflam store
Funnels

Question 8

Explain the Pre-Wet system.

Answer 8

The pre wet system when put to use protects the top deck of the ship from biological/chemical weapons and nuclear debris by coating it in water and preventing any substances from sticking to the deck

Question 9

Explain the system configuration in DC State 1.

Answer 9

All the pumps are running
The DC State 1 Valves are shut
The HPSWM is divided (isolated) into zones

Question 10

Explain the system configuration in DC State 3.

Answer 10

One pump is running (one pump can supply the whole ship)
Other pumps are on stand-by and can be started if pressure drops
All the DC State valves are open

Question 11

When may more pumps be introduced?

Answer 11

When the pressure drops below 7bar

Question 12

State the machinery being cooled by the Main Propulsion cooling system.

Answer 12

Gas Turbine Cooling
Plumber block emergency cooling
Main Forced Lub system cooling
Controllable Pitch Propeller (CPP) cooling – if fitted

Question 13

State the machinery being cooled by the Auxiliary cooling system.

Answer 13

Diesel Generators

Air Conditioning Plants

Question 14

When would a cross connection between port and starboard be used?

Answer 14

When one sides intake needs to be isolated to clean out a strainer or provide other maintenance without stopping the system

Question 15

What temperature do white metal bearings melt at?

Answer 15

115 degrees

Question 16

What my happen to machinery if it is not correctly cooled?

Answer 16

could breakdown and seize, it could strip its bearings or it could catch fire from overheating

Question 17

Why is FW (Fresh Water) used in a cooling system?

Answer 17

Materials used in the equipment may be susceptible to Salt Water corrosion and may wear out exceptionally fast, The equipment or system cooled by the fresh water system could be seriously affected by Salt Water contamination.

Question 18

What definition of system is the FW/SW?

Answer 18

the SW system is a open loop system and the FW is a closed loop system

Question 19

When could the FW be Cross connected to the SW?

Answer 19

If the FRESH WATER PUMP fails, but this is only done in an emergency and the MEOs permission is required

Question 20

Whose permission would be needed?

Answer 20

MEO