HP pump size

[MillbrookMaple]

I have a 7.5 High Pressure Pump on my system. I was wondering if that would be enough to run 3 membranes. One single and one double housing all in series.

[Thad Blaisdell]

Yes it will run it. You wont get the 1800 gph, but you will be able to concentrate higher.

[doocat]

How do you make a two or three membrane machine concentrate higher? I have a two membrane 600 expandable. I get more flow but not higher brix in one pass. Is there a secret we are not using?

Craig

[TunbridgeDave]

doocat does it have a recirc pump? Mine doesn't but it does have a recirc valve. If i just one pass it, i get less than half the water out, but if I open the recirc valve and let the concentrate re-enter the hp pump I can get it up to as much as 75% water removal. The downside is I have to reduce the flow tremendously. So instead I just send the concentrate back to my bulk tank until it gets up to the level I want. Then I direct it up to the feed tank. It's more of a hands on approach but more efficient. I think the idea with RO is to maximize your permeate flow however you can removing the most water per hour.

[MillbrookMaple]

Our current post has the recirc pump mounted to the top of the housing(single). The new housing would be 2 membranes in one housing with recirculation plumbing running from the concentrate output before it goes into the other housing. I figured I should put a pump on that and pump it back into the feed side of the housing or between the feed pump and the HP pump. Any suggestions? With the housings in series I figured it would be like I am running 2 passes in one shot. I also thought I would put in bypasses on each housing so that when I run a rinse I can isolate each housing to maximize flow for cleaning. Material costs look to be around $4000 for the new 2 element housing, 2 new e8 membranes, a recirc pump and plumbing.

[Thad Blaisdell]

For that money I would sell the 600 gph RO and take the 4000 and buy a new 1200. H20 machines are not that much more. You may have to kick in a little more but you would have all the machine you need. Now is 2000 taps what you really have? Because if it is, a 2 post machine is way more than you need.

[MillbrookMaple]

For that money I would sell the 600 gph RO and take the 4000 and buy a new 1200. H20 machines are not that much more. You may have to kick in a little more but you would have all the machine you need. Now is 2000 taps what you really have? Because if it is, a 2 post machine is way more than you need.

If everything goes well we should be between 5000-6000 taps next season. We run 15% sap in our evaporator, which we plan to extend to a 10' this year also. We had a terrible time with sugar sand build up in the flue pan this year and the extra surface area will help our gph too.

[TunbridgeDave]

Get in touch with Joe at AtlanticRO. He has great prices on membranes and vessels.

[wiam]

Get in touch with Joe at AtlanticRO. He has great prices on membranes and vessels.

I have not found better prices for xle membranes. I have found better vessel prices.

[Jeff E]

As I understand it, one way to get the concentrate up is to run the membranes in series. Your concentrate output from membrane #1 is the feed for membrane #2. If your first membrane takes 50% of the water off, and the final removes lets say 75%. That would take 3% to 6%, then 6% to 18%.
Running the membranes parallel will give you much higher permeate capacity, but concentrate wont go above 75% water removal.

[Thad Blaisdell]

As I understand it, one way to get the concentrate up is to run the membranes in series. Your concentrate output from membrane #1 is the feed for membrane #2. If your first membrane takes 50% of the water off, and the final removes lets say 75%. That would take 3% to 6%, then 6% to 18%.
Running the membranes parallel will give you much higher permeate capacity, but concentrate wont go above 75% water removal.

That is not exactly how it works at all. One thing to figure into the equation, is that the higher you go the harder it gets. 2-8 is easy 8-16 much harder. Even though you are removing less water it is physically harder. Picture a tennis racquet, the sugar bounces back every time, the water only bounces back when it hits the strings. Now when you go higher the water is also bouncing off more sugar molecules. There are more and more sugars in the way to keep the water from escaping.

[doocat]

So is a two stage pump for two membranes the answer of how to get higher brix out of a two membrane machine?