Steve,
Just a quick reply since I'm about ready to hit the sack. I think you are
saying that the polishing system should be something that can be switched
inline on the way to the engine. That amounts to just more pre-engine
filtering.
What I want is a system that can recirculate fuel independent of the engine
system. From what I gather, recirculating fuel through a filtering system
will
result in clean fuel so that the engine system will not be stressed (lift
pump).
Also, much crud is built up while just sitting in the slip or on the hard
over
the winter. Better to clean it up prior to offering it up to the engine than
hitting the engine filters all at once.
Your ACSII schematic came across totally skewed. That is a problem
with proportional fonts and TABs
Doug
s/v Callista
"Steven Shelikoff" wrote in message
...
On Wed, 3 Dec 2003 21:10:23 -0500, "Doug Dotson" wrote:
Steve,
I understood that you were suggesting that I leave the polishing system
running while running the engine. Since I have 2 tanks it seems to me
to require two polishing systems to keep polishing while running. The
system I have designed allows me to polish either of the two tanks
at any time and run the engine out of either tank at any time as well. So
I can polish the same one I am running out of if I wish. I guess the
choice of which to polish while running is up for grabs.
I think I'd route it so that I can route either tank to the polishing
system then 'T' the polishing system to the engine and the return to
either tank. Just make sure you're returning to the same tank you're
drawing from. A simplified version (without bypass plumbing which is a
pain to draw) looks something like this: (view with fixed point font
like courier)
-------------- /--------------------------T---------|
| Y select / return to tanks | |
---------- | --------------- |
| | |(to tank 2) | check valve | |
| Tank 1 | --------------- |
| |---------- ------------- | |
---------- | | Polishing | -------- | ----------
|from | filters | | | | \ | |
Y select /----| with |-| Pump |-T- \-| Engine |
---------- /tanks| bypassing | | | | |
| | | ------------- -------- ----------
| Tank 2 | |
| |----------
---------- out
If the above ascii drawing looks horrible, sorry. But basically, the
supply from both tanks goes to a Y valve which feeds either to the
polishing filters. That's where you'd put the bypass valves so you can
go around any filter (GCF or Racor). Then to a T where one side goes to
a shutoff valve then to the engine. The shutoff valve is so that you
can turn off fuel to the engine while you're priming the system after
changing filters so air won't get in the engine. You can also plumb it
so that the engine can draw from the tanka bypassing the filters so you
can prime them and run the engine at the same time if that's a
requirement. I didn't care about that since I don't run the engine all
that much (sailboat.) Also not shown is that you want to install vacuum
gauges, one before the GCF filter, one between the GCF and the Racor and
one after the Racor before the Walbro pump. Any difference more than a
few psi across a filter means it's time for an element change.
The other side of the T goes to a check valve. That's there so that if
the electric pump fails the engine won't suck air from the return lines.
Then there's a T where the engine return and the polishing system return
join and go to another Y valve to select where to return the fuel to.
Just make sure both Y valves are in the same position. You can also use
this as a fuel transfering pump if you want to, by putting the Y valves
in different positions. But be careful you don't overflow the tank
being filled.
Steve