Project RO

[jmayerl]

Well here is my new to me RO. I haven't gotten ahold of a manual for it yet. It is a 6 post (4x40) culligan. Was just removed from service and working well as far as I know. My plan is to get new membranes, probably bypass the extra non essential electronics, and add a feed pump. Has anyone seen or converted one like this. I'm not an expert on them but I do currently have an RO and plan on just adding this to my fleet.

[jmayerl]

Found the manual and specs on the pump. It is a 1hp, multi stage( I think 10) 10 gpm.
So for all you RO guys.....how many of the six 4x40 posts should I use?

[jmayerl]

Tag on the pump

[mellondome]

1 maybe 2..
Make sure you have a good lift pump.

[DrTimPerkins]

The main thing to keep in mind is the way it is plumbed, you need to keep what is normally rejected by this machine, and reject what is normally kept. Otherwise you're going to have a LOT of boiling to do, and not a lot of syrup to show for it. :)

[jmayerl]

1 maybe 2..
Make sure you have a good lift pump.
Hmmm, what makes you think that? I have a 2 post 4x40 with a smaller pump with half the GPM rating.

[jmayerl]

The main thing to keep in mind is the way it is plumbed, you need to keep what is normally rejected by this machine, and reject what is normally kept. Otherwise you're going to have a LOT of boiling to do, and not a lot of syrup to show for it. :)
Haha, thanks Doc!
I did forget to mention I need to swap out all the lines to beef it up to a 300 psi unit

[mellondome]

Without recircularion internal to the membrane posts, your max water removal will be some where between 150psi and 175psi. I used to run a 4x40 with a 1ph 10gpm multistage goulds pump with a 3/4hp lift pump feeding it. The flow @ pressure wasnt enough for 2 membranes in parallel. It may have been in series, but not sure. The 10gal/min is at no pressure. You need to find the pressure / flow curve for the pump to know. Also you will need the specs from the membrane manufacturer for max pressure loss across the membrane and flow rates across the membrane surface. For best performance you will want close to max surface flow allowed.

[jmayerl]

Interesting, I currently run a much smaller pump with 2 posts. No recirculating pump but a needle valve and recirculating loop. I run 250-275 psi and can go up to 10% but it is much more efficient time wise to go to 5-6% and then run a second time to 8-10.

[mellondome]

What is your other pump?
If it is the deer run in your signature, that is probably a pressure washer pump . ( piston pump ) .
2 completely different things

[neil2fish]

jmayerl,
I did a similar project last year having been given a 4x40 8 post unit that came out of a dialysis center. I pretty much tore it down and rebuilt using the parts and completely eliminating the electronics in favor of a VFD with a control circuit and my own pressure switches. I ended up using 3 posts- two in parallel feeding one in series. I got the pyramid idea from the guys at MES. We are using their 120gph membranes. When I got the unit it came with a 5hp, 3phase, 35 stage pump. I quickly abandoned that... The pile also included a 2hp 5 stage Grundfos that I coupled to a phase converting VFD also from MES. I was never able to achieve pressures higher than 150psi at 120 gph. I have been told by a commercial plumbing contractor that those pumps do not like viscosity and has suggested a positive displacement pump. This year I'll be looking at procons- probably 240-265gph and without the relief valve. I'm hoping to run 200-225psi. I anticipate i should get around 200gph at that pressure and theoretically get 8% in one pass. Just not sure yet how much motor I'll need for that. I will get a 3phase and use the VFD as a throttle to find the sweet spot - so to speak. If i can't get 8% I'll add a recirc loop which will slow my output, but I'm going to add a low pressure switch to the feed pump so I can turn it on in the morning and come home from work and boil concentrate. That's the plan...actual results may vary lol