RO/DI filter flow restictor question

[scottfarcuz]

Nah just pretty bored, and thought it would be good for a laugh...


Haven't hijacked a thread in a few weeks.

 

[mike660r]

It was worth the comical relief on a Friday while sitting at the office.

Don't tell my boss that

 

[mike660r]

I think I am going to go back to my original plan of just having one membrane in the 100-150 GPD range. I have the parts and thought I could easily build a frankenstien RO/DI. Its turning out to be more of a pain that I was anticipating.

 

[Bowman]

<a href=showthread.php?s=&postid=10859551#post10859551 target=_blank>Originally posted</a> by Rizing
i have a dual membrane spectrapure and it has the waste from membrane 1 going to membrane 2. then both product lines are merged into a t. spectrapure site has some manuals

Mike I have the same setup and the flow restrictor is placed in the final waste line. Mine uses 2 membranes of the same GPD and the flow restrictor is matched to that.. I.E. 2-75 GPD membranes with 1-75 GPD restrictor. My instructions also say to "tune" the restrictor to a 4 to 1 ratio by trimming the length of the restrictor to achieve the correct ratio. HTH

 

[funkyman]

Mike......print this out. The Flow Restrictor Table is on page 9:

http://www.spectrapure.com/manuals/MPDI_SYSTEM.pdf

 

[mike660r]

SWEEEET! This is the document I was looking for.

Thank you sir!

 

[Rizing]

heh work second shift sorry forgot about the whole original question. i use 2 75gpd as well with a slightly cut flow restrictor.

 

[funkyman]

 

[Buckeye Hydro]

You can plumb the membranes in parralel, with each membrane's waste water flowing through its own flow restrictor.

Especially if you have good pressure, You can plumb the membranes in series, with the waste water from the first going to the in port on the second membrane. In this case the two membranes function as a single long membrane, If you use two 75 gpd membranes in this way, you'd want a single flow restrictor for a 150 gpd membrane. Make sense?

 

[itZme]

Nice. So you can flow 150gpd through two 75gpd membranes in series? That's interesting. Is there any problem with matching the membranes such as if I wanted to add a second RO membrane to my Kent Maxxima 50 gpd can I just add another 50gpd and set a restrictor at 100gpd?

Another question about this is if you use 2 membranes in series will the first one go bad much earlier than the second one since it is seeing way more of the impurities or is it flowing through faster therefore removing less impurities during the first stage? Will this remove ~98% of the impurities and not end up going through much more DI resin?

Thanks for dropping in on this thread with some definitive answers.

 

[Buckeye Hydro]

<a href=showthread.php?s=&postid=10874931#post10874931 target=_blank>Originally posted</a> by itZme
Nice. So you can flow 150gpd through two 75gpd membranes in series? That's interesting. Is there any problem with matching the membranes such as if I wanted to add a second RO membrane to my Kent Maxxima 50 gpd can I just add another 50gpd and set a restrictor at 100gpd?

Correct

Another question about this is if you use 2 membranes in series will the first one go bad much earlier than the second one since it is seeing way more of the impurities or is it flowing through faster therefore removing less impurities during the first stage? Will this remove ~98% of the impurities and not end up going through much more DI resin?

The second membrane sees higher tds feed water than the first. The rejection will be based upon the factory specs for the membranes. What you may find is that a second DI stage may be needed to handle the higher flow rates (e.g., with two 100 gpd membranes).