Float Seal for Atmospheric Pressure Application

I understand the problem.

explain the application

what is the purpose of the floating riser?

is the fluid water?

what is the range of movement?

what is the seal made out of?

can you make the float bigger?

more lift & more weight will reduce the effect of the seal friction

Hi Garth,

Thank you for the reply!

what is the purpose of the floating riser? - The riser is a gravity feed from a pond, as the level rises/falls, the riser matches the pond level. The water looks like a mushroom when it flows out of the riser & down onto a bell shaped filter. The water cascades through the 500micron screen filter. Algae, leaves, twigs, etc form an obstruction to flow & are washed down the sides of the filter into a catch basin, that is flushed out every few days. Pretty slick , it's self cleaning filter.

is the fluid water? - Yes sir, you got it.

what is the range of movement? - 3 inches

what is the seal made out of? - Currently a hydraulic seal, sized so that it just barely touches the riser

can you make the float bigger? - Unfortunately not, it in a limited space....too much float material reduces the amount of water available for suction. A problem is also sticking when lowering.

more lift & more weight will reduce the effect of the seal friction - Yepper, you got it

I'm thinking of machining a delrin "seal" with minimal clearance to keep leaves that are 10 to 20 mils in thickness out of the sump (improperly labeled accumulator in my first post), but don't have the background to figure out if it "should" work.

Unless of course someone has a better idea!!!!!!!!!

Thank You Again,

Jon

so the seal keeps the crud out of the sump then?

maybe some milk jug [UHMW] for a seal,

old inner tube, cloth, rubberized canvas?

It sounds like the riser is rocking and binding. Can you add a guide rod to the riser going through a guide ring way above? Or add a skirt to the riser below to keep it straight. The skirt only needs minimal contact with the sides, to reduce friction. Three little nylon buttons would do.

Show us a diagram, so we can get a better idea of what you have.

Garth & Mike,

You guys have nailed it. I realized that I thought it operated under a vacuum......no way, it's atmospheric. I need to machine a "trash guard" out of some delrin with about 0.004" clearance, and check for binding/poor alignment on the bottom. It can't be anything else, because the riser PVC rides on the uptake from the pond. I need to check the uptake to ensure it is precisely vertical & free of gouges/etc.

Garth, thanks for the UHMW suggestion, got me to thinking about low friction materials that I can machine. I have some delrin that I can use.

Mike, thanks for the nylon button/alignment suggestion, nailed the fact that misalignment and/or friction could also be the problem at the lower end.

I can't post pictures since it's a buddy's project & he's not ready to go public with it. I really do appreciate all of your input, you guys are awesome.

Thanks Again,

Jon