Plumbing third post

[Sap Raider]

I have a water guys 2 post RO and I want to add a third post. The pressure pump is capable of doing this. I am not sure how to plumb it in. The raw sap comes in at the center of the first post and the concentrate comes out of the second post from the center. Do I just have the concentrate from the second post to the center of the third post? These are 4" MES membranes in a stainless housing.

[maple flats]

Are you sure? I think most are plumbed so the sap enters the outer plug on each membrane and the premeate exits the center. That gives the larger surface area in each membrane to stop the concentrate, the permeate will not plug out the center. If plumbed with the center getting the inflow on each membrane it seems the membrane would fowl up much faster. After use, if you were to pull a membrane before washing, the outside is coated, not the center, just like when you change the pre-filter.

[iby]

I agree with Dave..

on mine, each end has 2 holes.. on the end where the sap enters the tube, the center hole is plugged/capped. at the other end, the permeate comes out the center, and the concentrated sap comes out the outer hole.. the permeate is sent off to a holding tank... the concentrated sap is then sent to the next RO tube in the exact same fashion... it goes in the outer hole and the center is capped/plugged and the permeate comes out the other end in the middle... so if you want to add a third, you just do the same thing... where the concentrated sap comes out of the second tube, you plumb that to go into the outter hole on the new tube and plug the center..

[ddociam]

Hey guys. My set is going to be a two post R.O. that will empty out my gathering tank. I have a heated shop where I plan to do that. My evaporator is in my barn where I have a head tank elevated and hooked up to my float box.
I also have a single post R.O. which I was thinking about using to pump my concentrate into my head tank while removing more water.
I have a couple question:
Will that remove more water after going through a two post R.O.?
Would it be more effective just to make a three post R.O.
my two post has a 330 procon and a two hp motor.
Thoughts?


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[maple flats]

The RO will remove more water going thru a second time, but likely will remove less than the first time. When doing a second pass it is most effective if you can draw from one tank and send the concentrate to another tank. If you try to do a re-circulation for the second pass a stratification happens, where the concentrate settles lower in the tank than what is on top. Those who do a second pass find it best if the can draw the RO input from the center level in the tank rather than drawing from the bottom. Another idea that could help is to stir the tank periodically.

[Sap Raider]

I will check on the location of the input.

[ddociam]

Thank you Dave. I’ll give it a try.
Jerry


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[MT Pockets Producer]

Hi Scott. We are using the same membranes and housings. Feed goes into the outside fitting and permeate comes out the center fitting. If you are plumbing in series the concentrate from the existing membrane(outer fitting) should be plumbed into the outer ( feed) fitting of the new membrane. If plumbing parallel then you need to T into your existing feed lines and plumb that into the outer feed fitting of the new membrane. The membrane can only be fed from one direction but I believe it does not matter which end you discharge the concentrate from. Just plug the opposite end. Give me a call if I can be any assistance.

Joe

Corrected based on Maple Flats comments.

[maple flats]

Wrong, the inside (center) fitting is only for permeate unless something radical has changed. It just makes absolutely no sense for the center to be concentrate. The concentrate is the portion that never goes thru the membrane because it has molecules too large to pass (unless the membrane is passing some sugar, which is not good). The idea of an RO is to remove water from the sap, thus the sap enters membrane #1 on the outer port, and #2, #2 and any others, it still stays on the outer ports, the water that does pass thru the membrane (permeate) is always going to exit the center port on all membranes built as a cylinder, if some industries have a different design, it is not the maple industry.
MT, look closer to your connections and reason it out. For the feed to go in the outer and exit the center how does it ever remove any water?

[maple flats]

Regardless of how many membranes are in series, the center ports will do best if the center ports are teed togeather for a greater pressure differential across the membranes. Sometimes membranes are plumbed in parallel too, but the concentrate still enters the outer fitting, that can be if one has 3 or more membranes, #1 and 2 plumbed in parallel, then a third in series with the parallel pair. Larger RO's may have several parallel sets, each going to one or some in series. However on any configuration the sap or infeed is in the outer fitting and the concentrate bout the outer because the sugars could or should not pass thru the membrane.