Home Made RO

[Teuchtar]

Here is the piping schematic

[Teuchtar]

Pump arrangement:
Grey pump is M1
Blue pump is M2
Black pump is M3

[Teuchtar]

Piping arrangement:

[Teuchtar]

Membranes and filter:

[DanE.]

wow. this is great! Thanks for posting. Dane

[KenWP]

So what percentage of sugar does it bring the sap down to. If a guy could get down to 4% you would have lost half the water already. This may sound dumb but could a guy make a gravity system useing one of the membranes. Some how fill it up and wait till tomorrow and have even a 1/3 of the water go through .That would shorten up a boil a lot even.

[Teuchtar]

At 340 psi I have driven the sap as high as 16% by recycling back to the sap tank. But such high concentration fouls the membrane too fast, and is not so efficient overall. On a single pass, I can get up over 7%.
I suppose the cutoff of efficiency is when the RO is down to below 0.5 gpm of permeate it makes sense to continue to concentrate. This is just below the boiling rate for a 2x6. Go much lower than that, and I'm better to start up the evaporator.
I suppose you could just pick up a membrane and its housing and use gravity feed to drive the sap through. But unless you were on a good hillside, the performance would be very weak, and you'd be down to a trickle after only a few minutes of concentrating.
Those small 1/4hp carbonator pumps are so cheap and plentiful, you would probably want to think about that as a minimum instead of gravity. To get 300 psi, you'd need 700 feet of vertical rise, that might be 1/4 mile up the mountainside. At that point, the piping costs way more than a pump.
I'm not sure what is the ideal system pressure for 4% concentration. There's a couple of RO's on the market that make such a low concentration, but I think most people prefer to get higher concentration, which means more pressure and more recirculation. Bear in mind that the permeate flow is always dropping (since your last wash), so you soon get tired of watching that trickle.
Brent tried the GE merlins, which are essentially an RO driven by city water pressure, but I believe he needed to add a pump to help the sap along, and to flush and wash too.
Last year was my first year using this machine. I added the recirculator pump this year to boost the membrane flow. They seem to be happy with 8gpm on each membrane (16 gpm at the pump for twin towers).

[twobears1224]

thanks for the pic's and info.last night i got on the membrane website which tube did you use?? i see they have a bunch of diffrent ones.

delbert

[Brent]

there's no free lunch

if you need to pump the sap up 700 feet to get the pressure in the column,
forget about plumping up the hill because you'll already have the 300 psi pump to make it go up.

[Teuchtar]

I picked up the 4040 Stainless vessels. Good for 300 psi. Maybe not quite as good for 340.
Who needs a pump to go up the hill ? Thats one more good reason to need a new ATV or snowmobile.