Thinking of adding recirc

[Diesel Pro]

I have plenty of extra parts from my home build. I used a Procon 240 gph (have 265 as backup because the 240 weeps) and a single XLE 4040 membrane. No recirc at present, but I return to the same tank that I am condensing. I understand that I want to feed the recirc to the inlet of the Procon pump and that I want a needle valve to adjust flow.

Do I tee in my bypass feed into the high pressure between the membrane and the concentrate flow meter/needle valve or do I take my bypass from after the meter? I assume before?

I'm also not sure that I grasp what the bypass will do for me exactly other than send concentrate back to tank at a lower flow rate and higher concentration.

[Urban Sugarmaker]

I would search on here for Teuchtar's RO build. Also check out the MES Dolly. I think the pump they used for recirc is well-suited to that application. They use a Fluid-o-tek rotary vane pump for feed and a Goulds vertical multistage pump for recirc. I'm not sure a procon style pump is really all that good the recirc. I have been thinking about this too but I'm leaning toward just adding a membrane instead.

The recirc loop will keep the sap running through at high speed across the membrane and help delay membrane fouling. You would have a needle valve to "draw off" concentrate to boil. I think this also helps achieve a higher single pass brix but don't quote me. All the pro manufactured models seem to use recirc.

[Quabbin Hill Farms]

Where did you buy the membrane canisters?
THANKS

[Urban Sugarmaker]

Quabbin Hill, I'm not sure which one of us you are asking, but I got mine from Midwest RO.

[Flat Lander Sugaring]

you wont believe the difference with the recirc line. It T's off from the last membrane before the concentrate needle valve to a second needle valve and back to the input of the feed pump. bowhunter set me up with mine, cant believe i went 3 years before I did it.

[maple flats]

Many smaller commercial RO's do not use a recirc. pump, just tee off before the needle valve, put a needle valve in the recirc. line to regulate that flow and tee into the high pressure pump inlet.

[Flat Lander Sugaring]

if you have a feed pump and you T in between the feed pump and the high pressure you might find that the pressure coming out of the last membrane and the feed pump will fight each other.

you will be best to T in before the feed pump I think.

[Wanabe1972]

I know this is an old thread but im setting up a recirculation line on my homebuilt RO. I understand to T off between membrane and concentration needle and send it back to the inlet to the feed pump. Does everyone send concentrate back through the inline filter? I have always run batch through the RO once all the sap gets into the concentrate tank i will remove the filter and run it back through again. Ive really never thought about this before but i guess the filter doesnt affect the sap at lower concentrations but does it at higher concentrations. Jeff

[bowhunter]

I like to tee in between the filter and the pump bypassing the filter with the recirculation. Minimizing the flow through the filter minimizes the pressure drop through the filter which is a good thing for your pump.

[Wanabe1972]

Thanks Bowhunter this is what I was thimkimg. I'm going to replumb this week.