Depends on the pump.
Roller cell pumps won't/can't backflow. That is until some dirt has been
through it (or it has been run dry) and has shredded the roller tracks.
However, these types of pump normally have (and/or can be specified to have)
a built-in check valve that additionally prevents backflow.
Duncan McF.
----- Original Message -----
From: "Fergus Kyle" <VE3LVO@rac.ca>
Subject: Europa-List: Fuel pumps - par'l or series?
>
> Cheers,
> I have not monitored the net for the last three days, due new
> system, but I asked locally about the query regarding fuel pump
> installation, and the answer I got follows [permission not requested so
> source not divulged]:
>
> "| Rotax only recommends the series system with check valves. (As shown in
> the
> | maintenance manual Page 32) The reason is that at very high fuel demands
> the
> | parallel system may allow some fuel to bypass thru one of the pumps. We
> have
> | never witnessed this in practical application but it is the factories
> | opinion that it could happen.
> |
> | We have a neat fuel manifold that tidies up the fuel pump installation
but
> | it is not been tested yet. The factory has agreed it meets the drawing
> | criteria from the maintenance manual. See pic."
>
> I am looking into the manifold suggestion. Factory may wish to comment.
> Happy landings,
> Ferg
> A064
>
>
|