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HP Fuel Supply Pumps 12RT-flex96C

HP Fuel Supply Pumps 12RT-flex96C

There are eight of these pumps, each driven by three peaked cams. They supply fuel to the common rail.

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Brian ,
don't stand too close......! 1600 Bar goes through there.

Great photos though , please keep them coming .

Regards,
Rick
 

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Looks somewhat less complex than the Doxford system!
 

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Normal operational pressure is about 820bar for max power. The auto control valve lifts at 1000bar and the final manual relief valve is about 1290bar.
All eight fuel pumps discharge into the long tube in the centre which is known as the intermediate fuel ac***ulator. This had to be changed due to damaged seats where the non return valves locate.
These pumps are constantly jamming. Due to the design a pump can jam and the other seven are still enough to give you full power. However if two pumps jam then low fuel pressure slow down is activated, at about 550bar.
The pump can jam just proud of the three toed drive cam and the noise is something the hear when this happenns. Then the job has to be stopped to lift the fuel pump. Nice job in traffic lanes in approaches to Hong Kong.

Brian
 

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Hey Brian,

Re: Our previous discussion on Common Rail. Thanks for the post and explanantion! I notice you used "job". Is it still common, when handing over to ask "How's the Job?" and receive the answer,"Going up and down and round and round!"!

Regards,
Dave
 

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Yes it is still common to ask "How is the Job going?"
Particularly the Old Hands, like myself, who remember all watchkeeping ships.

Brian
 

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Maybe Percy J had it right? Don't remember too many problems with the Doxford system.
 

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I seem to remember the Doxford mechanical fuel injector!!!! Sector pins and all!!!! Quite a performance getting out of Birkenhead on a Clan Line boat.

Brian
 

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I remember a Doxford running on H.O. where the push rods attached to the bell crank levers lifting the fuel pump suction valves were bending during manoeuvring. The theory was that this was being caused by the cold breeze coming from the shaft tunnel causing a slug of cold fuel at the fuel pumps while the engine was stopped.

Closed the tunnel W/T door - problem solved.

Derek
 

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