RO pressure ?

[Daryl]

I built a 3 membrane RO. The feed pump is a 3/4 HP Sears shallow well pump and the pressure pump is a series 5 procom with a 1HP motor. When I went to rinse the membranes, it would not raise the pressure over 50psi. The procon pump doesn't have a releif valve.
Does anyone have a idea to why the pump will not build pressure?:confused:
Thanks for any help.

[Brent]

My guess too many membranes and not enough pump.

Mine has 1 Hp feed and 3 Hp hi pressure on only 2 4x40 membranes. If yours are the same size you need at least 3 hp., maybe 5.

If the membranes are the new XLEs, they run well at lower pressures and you may be OK with a 3 Hp. on 3 of them.

[Daryl]

Brent,

What make and or model would you recommend? Would you think it best to just go down to one or two?
Thank you
Daryl

[Brent]

We use Walrus pumps on our machine tools and I've got a couple of them at home. Used one constant pressure pump on a GE merlin RO that worked well ... but that model tops out at 80 PSI.

You can check out Walrus Ameraica at
http://www.walrusamerica.com/products.html

These are knock offs of the world's best ... Grunfoss (German)

The problems I think you'll run into are
1) getting a big 220/1/60 motor on a 3 or 5 Hp pump
2) the off the shelf pumps will not have the ports you'll need to replicate the re-circulation circuits that are welded into the pump stages at different places. I think the commercial builders buy stock pumps and modify them. Good luck, I think you've got a challenge ahead.

[Daryl]

3 Phase motors aren't a problem. I have the power in my tool shop beside my suger house. Would it just be best to drop back to one membrane until I can find a higher powered pump?

[Brent]

If you've got sap running, I'd try it with just one for now.

At this time of year it's pretty late to be experimenting.

I think I'd be calling one of the builders in Quebec and get a ready to go pump.

What's the spec on your membranes ??

[Daryl]

XLE 4 X 40.
Sap is turned on on the other side of the Lake Erie. Looks like a big week ahead.

[Brent]

Well at least you've got the best low pressure / energy efficient membrane out there. Hope it works one way or the other

[metalhead62]

wpould need to hear alot more of the setup but 1st ? that comes to mind is do u have a valve on the concintrate out line to control pressure and then have u run it yet or r u just trying to wash membranes?

[metalhead62]

let me also tell u i have not built 1 yet but have been doing alot of homework on these i will not be around 4 a couple of days but green4310 seems to know alot on this subject u might try to pm him

[metalhead62]

daryl what did u come up with get any answers

[Daryl]

The problem was a procon pump from E-bay was bad. I got a new pump and it works ok.Went from 1 3/4% to 5+% in one pass. sure saves time and wood. Tomarrow , we are going to run it thru 2 times to see how much more we get.
Daryl

[metalhead62]

can u give me a sketch of how u put that together u used 3 membranes right? and still only got it to 5%in 1 pass?????