The threshhold amount requiring licensing and "proper" transporting vehicle may vary from state to state but in this neck of the woods folks transport 100 to 200 gallons of diesel in either drums or a fuel tank
on a pickup bed
all the time. Used for refueling equipment
. Given that most boats don't hold more than 100 gallons, legal
transportation doesn't sound like a real issue, although I'd be a lot more circumspect about gasoline than diesel. In any event, I have a couple of real questions...
(1) I've been looking at a variety of diesel transfer pumps and Racor filters (spin-on centrifugal type preferred?) and would like to turn the contents of each 40 gallon tank over at least
3 times during a single
polishing. That means 120 gallons total flow per tank which can be done in a couple of hours with a 60 gph pump or in an hour with a 120 gph unit. The pump and filter costs goes up rapidly with size so I'm leaning towards a 2 hour polishing at 60 gph. Sound reasonable? Or is the flow rate too low to stir up the tank contents?
(2) How important is it to balance the pump capacity with the filter capacity? Filter pressure drop doesn't look high enough to be a consideration, so a pump rated at 60 gph (likely rated wide open, against zero head) will probably put out almost that much flow through short large-diameter lines. But if I used a 120 gph pump with a 60 gph filter, what would be the consequence? Poor separation??? Or a pump that is struggling (overloaded) trying to suck too much fuel through too small a filter? Or something else I haven't though of?
(3) I've also seen setups that use two filters in series (NOT in parallel) --- why would anyone do this? Unless the first filter is 10 or 20 microns and the second is two microns, and longer run times can be had. Of course, two parallel filters will double the filtering rate but that might be more cheaply done with a single
(4) Does anyone see a problem with piping the system so that the polishing pump can also be used to force fuel through, and bleed, the main injection pump?
(5) What's the best pump type: diaphragm, vane, or gear
. All are positive displacement
and all should be self-priming to some extent. None of them like having a closed discharge (so some kind of pressure relief might be needed?) but does one of them have better characteristics in this application than the others?
I want to get this one right the fist time, so all input will be much appreciated.