fuel system arrangement

[Waltthesalt]

Any comments on a fuel system arrangement that allows one of the filters to be used for fuel polishing as well as regular operations?

[s/v Jedi]

http://www.sv-jedi.org/sv_jedi/2006/...fuel_syst.html

[model 10]

Nice but why 2 pumps? I guess if it's a boat part one will probably fail? Do you use O ring fittings or pipe thread because you sure have a bunch.

[s/v Jedi]

Originally Posted by Guy

Nice but why 2 pumps? I guess if it's a boat part one will probably fail? Do you use O ring fittings or pipe thread because you sure have a bunch.

When you follow the link I posted above the picture, then you get the full blog entry with pictures etc.

There are two pumps for different applications: one is mainly for bleeding everything that comes behind it and also a boost pump to help push fuel through a mostly clogged filter in tight situations. The output of this pumps connects to the feed-manifold.

The second pump connects to the return manifold and it's main purpose is polishing and also transferring fuel between tanks.

Both pumps draw from the transfer manifold and share the same filter turbine on their vacuum side.

The manifolds are very easy to make: just 1/4" bras/bronze T's and nipples and I used Permatex Hi-temp thread sealant (rated for hydraulics). Everything is bone-dry, no sweating. The mini valves are very nice and can be seen on the pictures. I think Port Supply (West Marine wholesale) has everything that I used.

I designed this system many years ago but took the core of it from how this is done aboard Nordhavn trawlers. It's proven design and never required any maintenance other than cleaning the filter over the years.

The system becomes much simpler with one tank only, without genset etc.

[model 10]

I see no need for a second pump unless you go with 2 pumps are better than one. Unfortunatly you are 2x as likley to have a pump failure. Looks like a valve would work instead. Still it's nice. Gives me ideas.

[heintje23]

Nice layout.

Has anyone experience with Velcon filters? Water is chemically binded by forming a gel with the filter material.

[model 10]

The one we used shut down fuel flow if they got any water. I never understood that in an aircraft but in a boat it would be great.

[s/v Jedi]

Originally Posted by Guy

I see no need for a second pump unless you go with 2 pumps are better than one. Unfortunatly you are 2x as likley to have a pump failure. Looks like a valve would work instead. Still it's nice. Gives me ideas.

Everything can break; it never did though so has proven reliable. The reason for two pumps comes up when you want to take on fuel from a rusty drum and filter it while you do. I used Walbro 6800 pumps for this IIRC and two pumps in parallel pump to the maximum capacity of a Racor 500 series filter. It still takes a while for 55 gallons, but it all gets filtered before it even comes aboard.

[Allan S]

Very nice set up Jedi, I am extremely envious of the room you have in your engine compartment. I had to settle in making my own portable fuel polishing system from parts from a boat wrecking yard.