Leaking Sugar, HELP!

[DocsMapleSyrup]

Tonight I had 400 gallons of 2.4% brix sap. I just built a two post, 4x40 membrane build. The membranes are from a well known membrane supplier to the maple industry. Last week I ran 200 gallons of softened well water through the unit, then did a 20 minute was as directed and flushed again with 200 gallons of fresh softened well water. I left the concentrate valve wide open during the rinses and wash. Tonight I started to RO the sap. My flow meter was at 0.5 gym concentrate and I decided to check my permeate line. I was getting 2.2 % brix. What the world. I ran through the entire 400 gallons and my permeate read 1.8 at the end. I could taste sugar. Needing help please.

[Thompson's Tree Farm]

check your u cup seals

[blissville maples]

Either seals aren't installed correctly or the valve configuration is incorrect, somehow somewhere a 3 way valve may be installed incorrectly, but it's really hard to say without being there to diagnose.

This is one thing about building your own machine is your the only one who knows about it and it's extremely hard to get any support.

But there's really only three reasons why you would pass sugar one is a blown membrane 2 is a bad seal on either end, or 3 valves configured wrong.

An ro is a very simple machine when it comes down to it.

[maple flats]

Also, assuming the seals are correct, when you flush you want the flows roughly equal, for both concentrate and permeate, if you had the valve wide open (and you plumbed correctly) you pushed a huge majority thru the housing and out on the concentrate side, and very little thru the membrane on the permeate portion. To flush both should be the same flow, and during the process adjust the pressure as necessary to keep them equal. That's even if you are small and get .1 gpm on each or larger and get 4 gpm on each or any other flows, just equalize them using the needle valve to raise or lower the pressure.

[maple flats]

Describe how it is plumbed please. From the high pressure pump what hoses connect to where on the membrane housings. The outter should always be sap or concentrate, out the center should be permeate.
Also, to others, can you use softened water to flush a membrane, I don't know. Would salt in the softened water cause any issues?

[DocsMapleSyrup]

The concentrate flows on the outside of the membranes. The permeate on the inside. The plumbing goes from the procon pump high pressure to the outside of the one membrane then to the next membrane, then to the needle valve and then through the flow meter. I did pull off the top caps tonight. I did find that the inner O-rings on the permeate side of the end caps (the smaller O-rings in the middle opening) seems to be off center. There is more O-ring exposed to one side of the O-ring than the other side by 1-2 mm and the rings fit in the grooves snug. ? manufacturing error? Also, One of the 4" O-rings on the outside of one of the end caps has some impurity embedded in the O-ring but that seems like it would affect the seal of the cap to the vessel and not interfere with the Permeate/Concentrate part.

[DocsMapleSyrup]

Problem solved! Took the membranes out of the housing and found that I had rolled an O-ring in the bottom cap of one of the canisters. Fixed that. I was able to totally clean up the permeate, zero sugar! I ran the pressure up to 300 psi and nothing blew. Hoping to run in the 250-275 range. Thanks for the ideas!

[SeanD]

Also, assuming the seals are correct, when you flush you want the flows roughly equal, for both concentrate and permeate, if you had the valve wide open (and you plumbed correctly) you pushed a huge majority thru the housing and out on the concentrate side, and very little thru the membrane on the permeate portion. To flush both should be the same flow, and during the process adjust the pressure as necessary to keep them equal. That's even if you are small and get .1 gpm on each or larger and get 4 gpm on each or any other flows, just equalize them using the needle valve to raise or lower the pressure.

Chad, I'm glad you had a simple fix! That's a good feeling.

Dave, for clarification when you are talking about flushing with equal flow rates are you just talking about the short flush of the sugar out of the membranes after concentrating?

When I flush with permeate after a soap wash or even during a soap wash, I have the high pressure valve wide open and the needle valve closed.

[Super Sapper]

When you flush or clean you want as much scouring as possible so the max flow through the concentrate side will clean the best. There should be nothing to clean on the permeate side.