REFLECTOR: Check valves

[Al Gietzen]

Subject: Re: REFLECTOR: fuel feed - my solutions

 

Thanks Al. Since I draw fuel from the nearly bottom of the sump and with a
couple of inches of fuel in the tanks I would have thought I had about 15
inches. The pressure in the cabin while flying should be good most of a
pound. My alternate air for the airspeed seems to confirm that cabin
pressure is higher than static .

Oh well if they don't work  they don't weigh much.Next order from McMaster
carr perhaps I will order the 0 psi jobs.

Wayne

 

Wayne;

I guess I could have been less absolute, and said - almost more - and
probably won't open, but, you know - making a point.  

I'm thinking a caged ball check valve that is closed only by either gravity
or counter flow, that is installed at a slight incline to keep it closed, is
the way to go.  I think the ridiculously expensive Andair valve from AS
(http://www.aircraftspruce.com/catalog/appages/andaircheckvalve.php) is such
a valve, but the description is contradictory "The check valve is ideal for
tank vents and high pressure fuel pump bypass lines. Its extremely light
weight internal shuttle operates with the slightest pressure yet the
internal O-ring seals allow the unit to be used up to 50 PSI. Other
qualities include break out pressure less than 1 PSI. . . "  I suppose 0 is
less than 1 PSI.  I don't see anything at Mcmaster-Carr that looks reliable
that aren't also described with breakout pressures of some value.  With a
non spring loaded ball valve it must depend on orientation, and is rated for
the highest pressure position. Anybody know?

 

Al

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