RO membranes

[mac]

I have a simple question on how a membrane is plumbed in a pressure vessle, at least i thought it was an easy question. It's my understanding that the feed water to the membrane goes to the fitting on the outside of the end cap, the the RO water comes out the middle port. My question concerns which end does the cup seal on the membrane go? Is it the same end as the feed, or the opposite end?

 

[Washmee]

I have a simple question on how a membrane is plumbed in a pressure vessle, at least i thought it was an easy question. It's my understanding that the feed water to the membrane goes to the fitting on the outside of the end cap, the the RO water comes out the middle port. My question concerns which end does the cup seal on the membrane go? Is it the same end as the feed, or the opposite end?

..........

 

[Greg Pack]

http://msdssearch.dow.com/Published...seps/pdfs/noreg/609-00349.pdf&fromPage=GetDoc

 

[car washing systems inc]

I have a simple question on how a membrane is plumbed in a pressure vessle, at least i thought it was an easy question. It's my understanding that the feed water to the membrane goes to the fitting on the outside of the end cap, the the RO water comes out the middle port. My question concerns which end does the cup seal on the membrane go? Is it the same end as the feed, or the opposite end?

If you are talking about the seal that is on one side of the membrane it goes on the water feed side

 

[mac]

Thanks for your input. When I looked at the link that cfcw put up, it shows a diagram from Dow on the flow, and it shows the cup seal on the opposite end of the feed water. My supplier said the same thing as car washing systems inc though. Can both be right? Or does it matter? Inquiring minds want to know.

 

[MEP001]

The diagram linked doesn't actually show the V-seal at all. It just looks darker on that end in the drawing.

The V-seal is to stop water from flowing around the outside of the membrane and not through the filter. The water inlet should go on the end with the V-seal, as this is how V-seals work.

 

[Greg Pack]

More docs that might assist with proper installation and startup:

http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_07d0/0901b803807d0495.pdf?filepath=liquidseps/pdfs/noreg/609-02069.pdf&fromPage=GetDoc

http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_01c5/0901b803801c569b.pdf?filepath=liquidseps/pdfs/noreg/609-02077.pdf&fromPage=GetDoc

 

[mac]

Just so we can be referring to the same configuration, the membranes that I get have the V or cup seal facing down the length of the membrane, so that in order for it to expand and seal the feed water should come in from the opposite end, unless I'm missing something.

 

[MEP001]

So the side view looks like this?

________________>

That would be backwards from any that I've seen, but that would mean the water inlet would be on the left. The Dow membranes look like this:

________________<

 

[waright]

seal goes on the end opposite of flow, in other words on the feed end. some housings have a flow arrow on the side showing the water direction.

 

[mac]

Just got off the phone with mu supplier, Crane Environmental in FL, and was told that the seal goes on the end where the water feeds into, and this is the best part, it supposedly doesn't matter how the cup seal is orientated. We just got six of the 4 by 40 membranes from them and not all of the seals were on the same way. The reason I really want to know this is that this system dhould be producing about 6 gpm anf we're only getting about 2 out of it. Can't get NS, who made this, to even return a call.

 

[MEP001]

Since there's not really any pressure on the V-seal it probably doesn't matter which way it faces or which end it's on as long as there's a snug fit in the housing, but even if the seal were missing completely it wouldn't affect production by that much. The volume you get is more about the pressure on the membrane than the flow through it.